Effect of ketamine on endogenous pain modulation in healthy volunteers.

PubMed

Niesters, Marieke; Dahan, Albert; Swartjes, Maarten; Noppers, Ingeborg; Fillingim, Roger B; Aarts, Leon; Sarton, Elise Y

2011-03-01

Inhibitory and facilitatory descending pathways, originating at higher central nervous system sites, modulate activity of dorsal horn nociceptive neurons, and thereby influence pain perception. Dysfunction of inhibitory pain pathways or a shift in the balance between pain facilitation and pain inhibition has been associated with the development of chronic pain. The N-methyl-d-aspartate receptor antagonist ketamine has a prolonged analgesic effect in chronic pain patients. This effect is due to desensitization of sensitized N-methyl-d-aspartate receptors. Additionally, ketamine may modulate or enhance endogenous inhibitory control of pain perception. Diffuse noxious inhibitory control (DNIC) and offset analgesia (OA) are 2 mechanisms involved in descending inhibition. The present study investigates the effect of a ketamine infusion on subsequent DNIC and OA responses to determine whether ketamine has an influence on descending pain control. Ten healthy subjects (4 men/6 women) received a 1-hour placebo or S(+)-ketamine (40mg per 70kg) infusion on 2 separate occasions in random order. Upon the termination of the infusion, DNIC and OA responses were obtained. After placebo treatment, significant descending inhibition of pain responses was present for DNIC and OA. In contrast, after ketamine infusion, no DNIC was observed, but rather a significant facilitatory pain response (P<0.01); the OA response remained unchanged. These findings suggest that the balance between pain inhibition and pain facilitation was shifted by ketamine towards pain facilitation. The absence of an effect of ketamine on OA indicates differences in the mechanisms and neurotransmitter influences between OA and DNIC. Diffuse noxious inhibitory control responses following a 1-hour low-dose ketamine treatment displayed facilitation of pain in response to experimental noxious thermal stimulation. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Seeing and identifying with a virtual body decreases pain perception.

PubMed

Hänsel, Alexander; Lenggenhager, Bigna; von Känel, Roland; Curatolo, Michele; Blanke, Olaf

2011-09-01

Pain and the conscious mind (or the self) are experienced in our body. Both are intimately linked to the subjective quality of conscious experience. Here, we used virtual reality technology and visuo-tactile conflicts in healthy subjects to test whether experimentally induced changes of bodily self-consciousness (self-location; self-identification) lead to changes in pain perception. We found that visuo-tactile stroking of a virtual body but not of a control object led to increased pressure pain thresholds and self-location. This increase was not modulated by the synchrony of stroking as predicted based on earlier work. This differed for self-identification where we found as predicted that synchrony of stroking increased self-identification with the virtual body (but not a control object), and positively correlated with an increase in pain thresholds. We discuss the functional mechanisms of self-identification, self-location, and the visual perception of human bodies with respect to pain perception. Copyright © 2011 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

5-HT modulation of pain perception in humans.

PubMed

Martin, Sarah L; Power, Andrea; Boyle, Yvonne; Anderson, Ian M; Silverdale, Monty A; Jones, Anthony K P

2017-10-01

Although there is clear evidence for the serotonergic regulation of descending control of pain in animals, little direct evidence exists in humans. The majority of our knowledge comes from the use of serotonin (5-HT)-modulating antidepressants as analgesics in the clinical management of chronic pain. Here, we have used an acute tryptophan depletion (ATD) to manipulate 5-HT function and examine its effects of ATD on heat pain threshold and tolerance, attentional manipulation of nociceptive processing and mood in human volunteers. Fifteen healthy participants received both ATD and balanced amino acid (BAL) drinks on two separate sessions in a double-blind cross-over design. Pain threshold and tolerance were determined 4 h post-drink via a heat thermode. Additional attention, distraction and temperature discrimination paradigms were completed using a laser-induced heat pain stimulus. Mood was assessed prior and throughout each session. Our investigation reported that the ATD lowered plasma TRP levels by 65.05 ± 7.29% and significantly reduced pain threshold and tolerance in response to the heat thermode. There was a direct correlation between the reduction in total plasma TRP levels and reduction in thermode temperature. In contrast, ATD showed no effect on laser-induced pain nor significant impact of the distraction-induced analgesia on pain perception but did reduce performance of the painful temperature discrimination task. Importantly, all findings were independent of any effects of ATD on mood. As far as we are aware, it is the first demonstration of 5-HT effects on pain perception which are not confounded by mood changes.

Mood influences supraspinal pain processing separately from attention.

PubMed

Villemure, Chantal; Bushnell, M Catherine

2009-01-21

Studies show that inducing a positive mood or diverting attention from pain decreases pain perception. Nevertheless, induction manipulations, such as viewing interesting movies or performing mathematical tasks, often influence both emotional and attentional states. Imaging studies have examined the neural basis of psychological pain modulation, but none has explicitly separated the effects of emotion and attention. Using odors to modulate mood and shift attention from pain, we previously showed that the perceptual consequences of changing mood differed from those of altering attention, with mood primarily altering pain unpleasantness and attention preferentially altering pain intensity. These findings suggest that brain circuits involved in pain modulation provoked by mood or attention are partially separable. Here we used functional magnetic resonance imaging to directly compare the neurocircuitry involved in mood- and attention-related pain modulation. We manipulated independently mood state and attention direction, using tasks involving heat pain and pleasant and unpleasant odors. Pleasant odors, independent of attentional focus, induced positive mood changes and decreased pain unpleasantness and pain-related activity within the anterior cingulate (ACC), medial thalamus, and primary and secondary somatosensory cortices. The effects of attentional state were less robust, with only the activity in anterior insular cortex (aIC) showing possible attentional modulation. Lateral inferior frontal cortex [LinfF; Brodmann's area (BA) 45/47] activity correlated with mood-related modulation, whereas superior posterior parietal (SPP; BA7) and entorhinal activity correlated with attention-related modulation. ACC activity covaried with LinfF and periacqueductal gray activity, whereas aIC activity covaried with SPP activity. These findings suggest that separate neuromodulatory circuits underlie emotional and attentional modulation of pain.

Love as a Modulator of Pain

PubMed Central

Tamam, Sofina; Ahmad, Asma Hayati

2017-01-01

Pain is modulated by various factors, the most notable of which is emotions. Since love is an emotion, it can also modulate pain. The answer to the question of whether it enhances or reduces pain needs to be determined. A review was conducted of animal and human studies in which this enigmatic emotion and its interaction with pain was explored. Recent advances in neuroimaging have revealed similarities in brain activation relating to love and pain. At the simplest level, this interaction can be explained by the overlapping network structure in brain functional connectivity, although the explanation is considerably more complex. The effect of love can either result in increased or decreased pain perception. An explanation of the interaction between pain and love relates to the functional connectivity of the brain and to the psychological construct of the individual, as well as to his or her ability to engage resources relating to emotion regulation. In turn, this determines how a person relates to love and reacts to pain. PMID:28814928

Effects of psychological state on pain perception in the dental environment.

PubMed

Loggia, Marco L; Schweinhardt, Petra; Villemure, Chantal; Bushnell, M Catherine

2008-09-01

Psychological factors have an important influence on pain perception. Both in the clinic and in experimental settings, distraction has been shown to reduce pain. Further, negative emotions increase pain, whereas positive emotions have the opposite effect. Other more complex psychological states alter the way we feel pain. For instance, empathy for another person who is suffering increases our own pain experience, and expectation of pain relief underlies much of the placebo effect. Neuroimaging studies show a physiological basis for psychological pain modulation, with activity in pain pathways altered by attentional state, positive and negative emotions, empathy and the administration of a placebo. The same psychological factors activate intrinsic modulatory systems in the brain, including those stimulated when opiates are given for pain relief. It is important for the dentist and patients to understand the influence of psychological state on pain transmission. Such an understanding will not only help patients learn how to participate in their own pain control, but will also help the clinician create a fostering environment.

The influence of music and music therapy on pain-induced neuronal oscillations measured by magnetencephalography.

PubMed

Hauck, Michael; Metzner, Susanne; Rohlffs, Fiona; Lorenz, Jürgen; Engel, Andreas K

2013-04-01

Modern forms of music therapy are clinically established for various therapeutic or rehabilitative goals, especially in the treatment of chronic pain. However, little is known about the neuronal mechanisms that underlie pain modulation by music. Therefore, we attempted to characterize the effects of music therapy on pain perception by comparing the effects of 2 different therapeutic concepts, referred to as receptive and entrainment methods, on cortical activity recorded by magnetencephalography in combination with laser heat pain. Listening to preferred music within the receptive method yielded a significant reduction of pain ratings associated with a significant power reduction of delta-band activity in the cingulate gyrus, which suggests that participants displaced their focus of attention away from the pain stimulus. On the other hand, listening to self-composed "pain music" and "healing music" within the entrainment method exerted major effects on gamma-band activity in primary and secondary somatosensory cortices. Pain music, in contrast to healing music, increased pain ratings in parallel with an increase in gamma-band activity in somatosensory brain structures. In conclusion, our data suggest that the 2 music therapy approaches operationalized in this study seem to modulate pain perception through at least 2 different mechanisms, involving changes of activity in the delta and gamma bands at different stages of the pain processing system. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Joint Mobilization Enhances Mechanisms of Conditioned Pain Modulation in Individuals With Osteoarthritis of the Knee.

PubMed

Courtney, Carol A; Steffen, Alana D; Fernández-de-Las-Peñas, César; Kim, John; Chmell, Samuel J

2016-03-01

An experimental laboratory study with a repeated-measures crossover design. Treatment effects of joint mobilization may occur in part by decreasing excitability of central nociceptive pathways. Impaired conditioned pain modulation (CPM) has been found experimentally in persons with knee and hip osteoarthritis, indicating impaired inhibition of central nociceptive pathways. We hypothesized increased effectiveness of CPM following application of joint mobilization, determined via measures of deep tissue hyperalgesia. To examine the effect of joint mobilization on impaired CPM. An examination of 40 individuals with moderate/severe knee osteoarthritis identified 29 (73%) with impaired CPM. The subjects were randomized to receive 6 minutes of knee joint mobilization (intervention) or manual cutaneous input only, 1 week apart. Deep tissue hyperalgesia was examined via pressure pain thresholds bilaterally at the knee medial joint line and the hand at baseline, postintervention, and post-CPM testing. Further, vibration perception threshold was measured at the medial knee epicondyle at baseline and post-CPM testing. Joint mobilization, but not cutaneous input intervention, resulted in a global increase in pressure pain threshold, indicated by diminished hyperalgesic responses to pressure stimulus. Further, CPM was significantly enhanced following joint mobilization. Diminished baseline vibration perception threshold acuity was enhanced following joint mobilization at the knee that received intervention, but not at the contralateral knee. Resting pain was also significantly lower following the joint intervention. Conditioned pain modulation was enhanced following joint mobilization, demonstrated by a global decrease in deep tissue pressure sensitivity. Joint mobilization may act via enhancement of descending pain mechanisms in patients with painful knee osteoarthritis.

Nurses' perceptions and experiences regarding Morphine usage in burn pain management.

PubMed

Bayuo, J; Agbenorku, P

2015-06-01

Morphine, a classical example of opioid has been described as one of the analgesics of choice for burn pain management but there have been reports of under utilization of the medication and subsequent poor pain management. Nurses have a pivotal role in successful burn pain management and should therefore possess positive perception as well as strong knowledge base of pain care. In light of this realization, this study sought to investigate the perception and experiences of nurses working in the burns unit possess towards the medication. Purposive sampling approach was used to select twenty (20) nurses. Descriptive and themed content analysis approaches were used to analyze data. Mean years in general nursing practice and practice in the burns unit were obtained as 7.4 and 3.4 years respectively. Results indicate that nurses have a clear understanding of the intensity of burn pain but perception towards morphine was mixed and some respondents were unsure about some of the pertinent facts of morphine and thus, would prefer other medications such as paracetamol, diclofenac and pethidine. Addiction to the medication and morphine causing death were major themes identified. The resultant effect of these perception and experiences imply and confirm the under usage of morphine. It is therefore recommended that nurses within the burn unit be taken through training modules on the suitability of morphine in burn pain management. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

Intramuscular temperature modulates glutamate-evoked masseter muscle pain intensity in humans.

PubMed

Sato, Hitoshi; Castrillon, Eduardo E; Cairns, Brian E; Bendixen, Karina H; Wang, Kelun; Nakagawa, Taneaki; Wajima, Koichi; Svensson, Peter

2015-01-01

To determine whether glutamate-evoked jaw muscle pain is altered by the temperature of the solution injected. Sixteen healthy volunteers participated and received injections of hot (48°C), neutral (36°C), or cold (3°C) solutions (0.5 mL) of glutamate or isotonic saline into the masseter muscle. Pain intensity was assessed with an electronic visual analog scale (eVAS). Numeric rating scale (NRS) scores of unpleasantness and temperature perception, pain-drawing areas, and pressure pain thresholds (PPTs) were also measured. Participants filled out the McGill Pain Questionnaire (MPQ). Two-way or three-way repeated measures ANOVA were used for data analyses. Injection of hot glutamate and cold glutamate solutions significantly increased and decreased, respectively, the peak pain intensity compared with injection of neutral glutamate solution. The duration of glutamate-evoked pain was significantly longer when hot glutamate was injected than when cold glutamate was injected. No significant effect of temperature on pain intensity was observed when isotonic saline was injected. No effect of solution temperature was detected on unpleasantness, heat perception, cold perception, area of pain drawings, or PPTs. There was a significantly greater use of the "numb" term in the MPQ to describe the injection of cold solutions compared to the injection of both neutral and hot solutions. Glutamate-evoked jaw muscle pain was significantly altered by the temperature of the injection solution. Although temperature perception in the jaw muscle is poor, pain intensity is increased when the muscle tissue temperature is elevated.

Magnitude and Temporal Variability of Inter-stimulus EEG Modulate the Linear Relationship Between Laser-Evoked Potentials and Fast-Pain Perception

PubMed Central

Li, Linling; Huang, Gan; Lin, Qianqian; Liu, Jia; Zhang, Shengli; Zhang, Zhiguo

2018-01-01

The level of pain perception is correlated with the magnitude of pain-evoked brain responses, such as laser-evoked potentials (LEP), across trials. The positive LEP-pain relationship lays the foundation for pain prediction based on single-trial LEP, but cross-individual pain prediction does not have a good performance because the LEP-pain relationship exhibits substantial cross-individual difference. In this study, we aim to explain the cross-individual difference in the LEP-pain relationship using inter-stimulus EEG (isEEG) features. The isEEG features (root mean square as magnitude and mean square successive difference as temporal variability) were estimated from isEEG data (at full band and five frequency bands) recorded between painful stimuli. A linear model was fitted to investigate the relationship between pain ratings and LEP response for fast-pain trials on a trial-by-trial basis. Then the correlation between isEEG features and the parameters of LEP-pain model (slope and intercept) was evaluated. We found that the magnitude and temporal variability of isEEG could modulate the parameters of an individual's linear LEP-pain model for fast-pain trials. Based on this, we further developed a new individualized fast-pain prediction scheme, which only used training individuals with similar isEEG features as the test individual to train the fast-pain prediction model, and obtained improved accuracy in cross-individual fast-pain prediction. The findings could help elucidate the neural mechanism of cross-individual difference in pain experience and the proposed fast-pain prediction scheme could be potentially used as a practical and feasible pain prediction method in clinical practice. PMID:29904336

Seeing the Body Distorts Tactile Size Perception

ERIC Educational Resources Information Center

Longo, Matthew R.; Sadibolova, Renata

2013-01-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of…

Rehabilitation Medicine Approaches to Pain Management.

PubMed

Cheville, Andrea L; Smith, Sean R; Basford, Jeffrey R

2018-06-01

Rehabilitation medicine offers strategies that reduce musculoskeletal pain, targeted approaches to alleviate movement-related pain, and interventions to optimize patients' function despite the persistence of pain. These approaches fall into four categories: modulating nociception, stabilizing and unloading painful structures, influencing pain perception, and alleviating soft tissue musculotendinous pain. Incorporating these interventions into individualized, comprehensive pain management programs offers the potential to empower patients and limit pain associated with mobility and required daily activities. Rehabilitative approach may be particularly helpful for patients with refractory movement-associated pain and functional vulnerability, and for those who do not wish for, or cannot, tolerate pharmacoanalgesia. Copyright © 2018 Elsevier Inc. All rights reserved.

Altered neural responses to heat pain in drug-naive patients with Parkinson disease.

PubMed

Forkmann, Katarina; Grashorn, Wiebke; Schmidt, Katharina; Fründt, Odette; Buhmann, Carsten; Bingel, Ulrike

2017-08-01

Pain is a frequent but still neglected nonmotor symptom of Parkinson disease (PD). However, neural mechanisms underlying pain in PD are poorly understood. Here, we explored whether the high prevalence of pain in PD might be related to dysfunctional descending pain control. Using functional magnetic resonance imaging we explored neural responses during the anticipation and processing of heat pain in 21 PD patients (Hoehn and Yahr I-III) and 23 healthy controls (HC). Parkinson disease patients were naive to dopaminergic medication to avoid confounding drug effects. Fifteen heat pain stimuli were applied to the participants' forearm. Intensity and unpleasantness ratings were provided for each stimulus. Subjective pain perception was comparable for PD patients and HC. Neural processing, however, differed between groups: PD patients showed lower activity in several descending pain modulation regions (dorsal anterior cingulate cortex [dACC], subgenual anterior cingulate cortex, and dorsolateral prefrontal cortex [DLPFC]) and lower functional connectivity between dACC and DLPFC during pain anticipation. Parkinson disease symptom severity was negatively correlated with dACC-DLPFC connectivity indicating impaired functional coupling of pain modulatory regions with disease progression. During pain perception PD patients showed higher midcingulate cortex activity compared with HC, which also scaled with PD severity. Interestingly, dACC-DLPFC connectivity during pain anticipation was negatively associated with midcingulate cortex activity during the receipt of pain in PD patients. This study indicates altered neural processing during the anticipation and receipt of experimental pain in drug-naive PD patients. It provides first evidence for a progressive decline in descending pain modulation in PD, which might be related to the high prevalence of pain in later stages of PD.

Future directions for the management of pain in osteoarthritis

PubMed Central

Sofat, Nidhi; Kuttapitiya, Anasuya

2014-01-01

Osteoarthritis (OA) is the predominant form of arthritis worldwide, resulting in a high degree of functional impairment and reduced quality of life owing to chronic pain. To date, there are no treatments that are known to modify disease progression of OA in the long term. Current treatments are largely based on the modulation of pain, including NSAIDs, opiates and, more recently, centrally acting pharmacotherapies to avert pain. This review will focus on the rationale for new avenues in pain modulation, including inhibition with anti-NGF antibodies and centrally acting analgesics. The authors also consider the potential for structure modification in cartilage/bone using growth factors and stem cell therapies. The possible mismatch between structural change and pain perception will also be discussed, introducing recent techniques that may assist in improved patient phenotyping of pain subsets in OA. Such developments could help further stratify subgroups and treatments for people with OA in future. PMID:25018771

Future directions for the management of pain in osteoarthritis.

PubMed

Sofat, Nidhi; Kuttapitiya, Anasuya

2014-04-01

Osteoarthritis (OA) is the predominant form of arthritis worldwide, resulting in a high degree of functional impairment and reduced quality of life owing to chronic pain. To date, there are no treatments that are known to modify disease progression of OA in the long term. Current treatments are largely based on the modulation of pain, including NSAIDs, opiates and, more recently, centrally acting pharmacotherapies to avert pain. This review will focus on the rationale for new avenues in pain modulation, including inhibition with anti-NGF antibodies and centrally acting analgesics. The authors also consider the potential for structure modification in cartilage/bone using growth factors and stem cell therapies. The possible mismatch between structural change and pain perception will also be discussed, introducing recent techniques that may assist in improved patient phenotyping of pain subsets in OA. Such developments could help further stratify subgroups and treatments for people with OA in future.

Ethnicity and OPRM variant independently predict pain perception and patient-controlled analgesia usage for post-operative pain.

PubMed

Tan, Ene-choo; Lim, Eileen C P; Teo, Yik-ying; Lim, Yvonne; Law, Hai-yang; Sia, Alex T

2009-06-23

Morphine consumption can vary widely between individuals even for identical surgical procedures. As mu-opioid receptor (OPRM1) is known to modulate pain perception and mediate the analgesic effects of opioid compounds in the central nervous system, we examined the influence of two OPRM polymorphisms on acute post-operative pain and morphine usage in women undergoing elective caesarean delivery. Data on self-reported pain scores and amount of total morphine use according to patient-controlled analgesia were collected from 994 women from the three main ethnic groups in Singapore. We found statistically significant association of the OPRM 118A>G with self-administered morphine during the first 24-hour postoperative period both in terms of total morphine (p = 1.7 x 10(-5)) and weight-adjusted morphine (p = 6.6 x 10(-5)). There was also significant association of this OPRM variant and time-averaged self-rated pain scores (p = 0.024). OPRM 118G homozygotes used more morphine and reported higher pain scores than 118A carriers. Other factors which influenced pain score and morphine usage include ethnicity, age and paying class. Our results suggest that ethnicity and OPRM 118A>G genotype are independent and significant contributors to variation in pain perception and postoperative morphine use in patients undergoing cesarean delivery.

Modulation of neural circuits underlying temporal production by facial expressions of pain.

PubMed

Ballotta, Daniela; Lui, Fausta; Porro, Carlo Adolfo; Nichelli, Paolo Frigio; Benuzzi, Francesca

2018-01-01

According to the Scalar Expectancy Theory, humans are equipped with a biological internal clock, possibly modulated by attention and arousal. Both emotions and pain are arousing and can absorb attentional resources, thus causing distortions of temporal perception. The aims of the present single-event fMRI study were to investigate: a) whether observation of facial expressions of pain interferes with time production; and b) the neural network subserving this kind of temporal distortions. Thirty healthy volunteers took part in the study. Subjects were asked to perform a temporal production task and a concurrent gender discrimination task, while viewing faces of unknown people with either pain-related or neutral expressions. Behavioural data showed temporal underestimation (i.e., longer produced intervals) during implicit pain expression processing; this was accompanied by increased activity of right middle temporal gyrus, a region known to be active during the perception of emotional and painful faces. Psycho-Physiological Interaction analyses showed that: 1) the activity of middle temporal gyrus was positively related to that of areas previously reported to play a role in timing: left primary motor cortex, middle cingulate cortex, supplementary motor area, right anterior insula, inferior frontal gyrus, bilateral cerebellum and basal ganglia; 2) the functional connectivity of supplementary motor area with several frontal regions, anterior cingulate cortex and right angular gyrus was correlated to the produced interval during painful expression processing. Our data support the hypothesis that observing emotional expressions distorts subjective time perception through the interaction of the neural network subserving processing of facial expressions with the brain network involved in timing. Within this frame, middle temporal gyrus appears to be the key region of the interplay between the two neural systems.

Increased Sensitivity to Thermal Pain and Reduced Subcutaneous Lidocaine Efficacy in Redheads

PubMed Central

Liem, Edwin B.; Joiner, Teresa V.; Tsueda, Kentaro; Sessler, Daniel I.

2005-01-01

Background: Anesthetic requirement in redheads is exaggerated, suggesting that redheads may be especially sensitive to pain. We therefore tested the hypotheses that women with natural red hair are more sensitive to pain, and that redheads are resistant to topical and subcutaneous lidocaine. Methods: We evaluated pain sensitivity in red-haired (n=30) or dark-haired (n=30) women by determining the electrical current perception threshold, pain perception, and maximum pain tolerance with a Neurometer CPT/C (Neurotron, Inc., Baltimore, MD). We evaluated the analogous warm and cold temperature thresholds with the TSA-II Neurosensory Analyzer (Medoc Ltd., Minneapolis, MN). Volunteers were tested with both devices at baseline and with the Neurometer after 1-hour exposure to 4% liposomal lidocaine and after subcutaneous injection of 1% lidocaine. Data are presented as medians [interquartile ranges]. Results: Current perception, pain perception, and pain tolerance thresholds were similar in the red-haired and dark-haired women at 2000, 250, and 5 Hz. In contrast, redheads were more sensitive to cold pain perception (22.6°C [15.1, 26.1] vs. 12.6°C [0, 20], P=0.004), cold pain tolerance (6.0°C [0, 9.7] vs. 0.0°C [0.0, 2.0], P=0.001), and heat pain (46.3°C [45.7, 47.5] vs. 47.7°C [46.6, 48.7], P=0.009). Subcutaneous, lidocaine was significantly less effective in redheads, e.g., pain tolerance threshold at 2000 Hz stimulation in redheads was 11.0 mA [8.5, 16.5] vs. >20.0 mA [14.5, >20] in others, P=0.005). Conclusion: Red hair is the phenotype for mutations of the melanocortin 1 receptor. Our results indicate that redheads are more sensitive to thermal pain and are resistant to the analgesic effects of subcutaneous lidocaine. Mutations of the melanocortin 1 receptor, or a consequence thereof, thus modulate pain sensitivity. PMID:15731586

µ-Conotoxins Modulating Sodium Currents in Pain Perception and Transmission: A Therapeutic Potential

PubMed Central

Tosti, Elisabetta; Boni, Raffaele

2017-01-01

The Conus genus includes around 500 species of marine mollusks with a peculiar production of venomous peptides known as conotoxins (CTX). Each species is able to produce up to 200 different biological active peptides. Common structure of CTX is the low number of amino acids stabilized by disulfide bridges and post-translational modifications that give rise to different isoforms. µ and µO-CTX are two isoforms that specifically target voltage-gated sodium channels. These, by inducing the entrance of sodium ions in the cell, modulate the neuronal excitability by depolarizing plasma membrane and propagating the action potential. Hyperexcitability and mutations of sodium channels are responsible for perception and transmission of inflammatory and neuropathic pain states. In this review, we describe the current knowledge of µ-CTX interacting with the different sodium channels subtypes, the mechanism of action and their potential therapeutic use as analgesic compounds in the clinical management of pain conditions. PMID:28937587

Has aerobic exercise effect on pain perception in persons with migraine and coexisting tension-type headache and neck pain? A randomized, controlled, clinical trial.

PubMed

Krøll, L S; Sjödahl Hammarlund, C; Gard, G; Jensen, R H; Bendtsen, L

2018-04-10

A large subset of persons with migraine suffers from coexisting tension-type headache and neck pain which may adversely affect the prognosis of migraine. Aerobic exercise has been shown to decrease migraine burden in these persons. Therefore, the aim of this study was to investigate whether the effect of aerobic exercise in persons with migraine and coexisting tension-type headache and neck pain can be explained by changes in pain perception. Seventy consecutively recruited persons with migraine and coexisting tension-type headache and neck pain were randomized into exercise group or control group. Aerobic exercise consisted of bike/cross-trainer/brisk walking for 45 min, three times/week for 3 months. Controls continued their usual daily activities. Pericranial tenderness, pain thresholds, supra-thresholds and temporal summation were assessed at baseline, after treatment and at follow-up (6 months from baseline). Fifty-two persons with migraine and coexisting tension-type headache and neck pain completed the study. Aerobic exercise did not induce consistent changes in nociceptive pathways measured by pericranial tenderness, pressure pain thresholds and sensitivity to electrical stimulation. The effect of aerobic exercise cannot be explained by measurable effects on the pain modulation system. Thus, the positive effect on migraine burden may rather be explained by positive alteration of avoidance behaviour. Aerobic exercise can be recommended as a safe and inexpensive migraine treatment strategy. This study adds further knowledge about the positive effect of aerobic exercise for persons with migraine and coexisting tension-type headache and neck pain. This effect cannot be measured by changes in pain modulation, but may rather be explained by positive alteration of avoidance behaviour. © 2018 European Pain Federation - EFIC®.

Reward Circuitry Plasticity in Pain Perception and Modulation

PubMed Central

DosSantos, Marcos F.; Moura, Brenda de Souza; DaSilva, Alexandre F.

2017-01-01

Although pain is a widely known phenomenon and an important clinical symptom that occurs in numerous diseases, its mechanisms are still barely understood. Owing to the scarce information concerning its pathophysiology, particularly what is involved in the transition from an acute state to a chronic condition, pain treatment is frequently unsatisfactory, therefore contributing to the amplification of the chronic pain burden. In fact, pain is an extremely complex experience that demands the recruitment of an intricate set of central nervous system components. This includes cortical and subcortical areas involved in interpretation of the general characteristics of noxious stimuli. It also comprises neural circuits that process the motivational-affective dimension of pain. Hence, the reward circuitry represents a vital element for pain experience and modulation. This review article focuses on the interpretation of the extensive data available connecting the major components of the reward circuitry to pain suffering, including the nucleus accumbens, ventral tegmental area, and the medial prefrontal cortex; with especial attention dedicated to the evaluation of neuroplastic changes affecting these structures found in chronic pain syndromes, such as migraine, trigeminal neuropathic pain, chronic back pain, and fibromyalgia. PMID:29209204

FMRI connectivity analysis of acupuncture effects on an amygdala-associated brain network

PubMed Central

Qin, Wei; Tian, Jie; Bai, Lijun; Pan, Xiaohong; Yang, Lin; Chen, Peng; Dai, Jianping; Ai, Lin; Zhao, Baixiao; Gong, Qiyong; Wang, Wei; von Deneen, Karen M; Liu, Yijun

2008-01-01

Background Recently, increasing evidence has indicated that the primary acupuncture effects are mediated by the central nervous system. However, specific brain networks underpinning these effects remain unclear. Results In the present study using fMRI, we employed a within-condition interregional covariance analysis method to investigate functional connectivity of brain networks involved in acupuncture. The fMRI experiment was performed before, during and after acupuncture manipulations on healthy volunteers at an acupuncture point, which was previously implicated in a neural pathway for pain modulation. We first identified significant fMRI signal changes during acupuncture stimulation in the left amygdala, which was subsequently selected as a functional reference for connectivity analyses. Our results have demonstrated that there is a brain network associated with the amygdala during a resting condition. This network encompasses the brain structures that are implicated in both pain sensation and pain modulation. We also found that such a pain-related network could be modulated by both verum acupuncture and sham acupuncture. Furthermore, compared with a sham acupuncture, the verum acupuncture induced a higher level of correlations among the amygdala-associated network. Conclusion Our findings indicate that acupuncture may change this amygdala-specific brain network into a functional state that underlies pain perception and pain modulation. PMID:19014532

[Hypertension, cardiovascular reactivity to stress and sensibility to pain].

PubMed

Conde-Guzón, P A; Bartolomé-Albistegui, M T; Quirós-Expósito, P; Grzib-Schlosky, G

To provide a review of empirical evidence of decreased pain perception in hypertensive persons or exaggerated cardiovascular reactivity to stress. To following article will briefly review the existing literature on the association between hypoalgesia and high blood pressure. In particular, evidence of hypoalgesia in normotensive individuals at increased risk for hypertension (exaggerated cardiovascular reactivity to stress) will be offered in support of the notion that high cardiovascular reactivity to stress and decreased pain perception may result from a common physiological dysfunction. Cardiovascular reactivity refers to changes in cardiovascular activity associated primarily with exposure to psychological stress. Different individuals show different amounts of reactivity under the same conditions. The greater cardiovascular reactivity to behavioral stressors may play some role in the development of sustained arterial hypertension. Central opioid hyposensitivity is hypothesized as a mechanism of both hypoalgesia and exaggerated autonomic and neuroendocrine responses to stress in individuals at risk for hypertension. The paraventricular nucleus of the hypothalamus (PVN) serves the crucial function of integrating cardiovascular and painful responses. The central opioid hyposensitivity model of hypoalgesia asserts that attenuation of inhibitory opioid input to the PVN may have important consequences for pain modulation. These consequences includes: 1) greater activation of baroreceptor reflex arcs, 2) enhanced release of endogenous opioids during stress, and 3) increased stimulation of descending pain modulation pathways. High elevated thresholds to painful thermal stressors might serve as a behavioral marker of risk for hypertension before the onset of high blood pressure levels.

Effects of Stress and Relaxation on Central Pain Modulation in Chronic Whiplash and Fibromyalgia Patients Compared to Healthy Controls.

PubMed

Coppieters, Iris; Cagnie, Barbara; Nijs, Jo; van Oosterwijck, Jessica; Danneels, Lieven; De Pauw, Robby; Meeus, Mira

2016-03-01

Compelling evidence has demonstrated that impaired central pain modulation contributes to persistent pain in patients with chronic whiplash associated disorders (WAD) and fibromyalgia (FM). However, there is limited research concerning the influence of stress and relaxation on central pain modulation in patients with chronic WAD and FM. The present study aims to investigate the effects of acute cognitive stress and relaxation on central pain modulation in chronic WAD and FM patients compared to healthy individuals. A randomized crossover design was employed. The present study took place at the University of Brussels, the University Hospital Brussels, and the University of Antwerp. Fifty-nine participants (16 chronic WAD patients, 21 FM, 22 pain-free controls) were enrolled and subjected to various pain measurements. Temporal summation (TS) of pain and conditioned pain modulation (CPM) were evaluated. Subsequently, participants were randomly allocated to either a group that received progressive relaxation therapy or a group that performed a battery of cognitive tests (= cognitive stressor). Afterwards, all pain measurements were repeated. One week later participant groups were switched. A significant difference was found between the groups in the change in TS in response to relaxation (P = 0.008) and cognitive stress (P = 0.003). TS decreased in response to relaxation and cognitive stress in chronic WAD patients and controls. In contrast, TS increased after both interventions in FM patients. CPM efficacy decreased in all 3 groups in response to relaxation (P = 0.002) and cognitive stress (P = 0.001). The obtained results only apply for a single session of muscle relaxation therapy and cognitive stress, whereby no conclusions can be made for effects on pain perception and modulation of chronic cognitive stress and long-term relaxation therapies. A single relaxation session as well as cognitive stress may have negative acute effects on pain modulation in patients with FM, while cognitive stress and relaxation did not worsen bottom-up sensitization in chronic WAD patients and healthy persons. However, endogenous pain inhibition, assessed using a CPM paradigm, worsened in chronic WAD and FM patients, as well as in healthy people following both interventions.

Asymmetric pain processing in Parkinson's disease.

PubMed

Granovsky, Y; Schlesinger, I; Fadel, S; Erikh, I; Sprecher, E; Yarnitsky, D

2013-10-01

Reduced endogenous pain inhibition, as part of the degenerative process, is presumed to be the mechanism underlying the common presence of pain in patients with Parkinson's disease (PD). The present study aimed to assess an endogenous pain inhibitory system in PD using the conditioned pain modulation paradigm. Twenty-six predominantly unilateral PD patients and 19 controls underwent psychophysical pain assessment before and after patients' morning dopaminergic medication. An unexpected increase in several parameters of pain perception for PD patients was found after dopaminergic medication (e.g. for 49°C noxious heat stimulation an increase from 70.6 ± 4.0 to 77.6 ± 4.0 on the numerical pain scale, P < 0.001). This increase was seen in patients with predominantly left-sided PD, regardless of the stimulated side (for 49°C noxious heat stimulation, predominantly left-sided PD patients, pain perception increased from 73.5 ± 6.8 to 85.0 ± 6.8, P < 0.001, whereas predominantly right-sided PD patients did not show a significant increase, 68.3 ± 6.8 to 70.4 ± 6.5, P = 0.777). Baseline efficiency of conditioned pain modulation inversely correlated with age at disease onset (r = -0.522; P = 0.009) and disease severity (Unified PD Rating Scale, r = 0.447; P = 0.032) but did not differ between patients and controls. Increased sensory response causing hyperalgesia occurs after dopaminergic medication in patients with predominantly left-sided PD. © 2013 The Author(s) European Journal of Neurology © 2013 EFNS.

Altered attentional control over the salience network in complex regional pain syndrome.

PubMed

Kim, Jungyoon; Kang, Ilhyang; Chung, Yong-An; Kim, Tae-Suk; Namgung, Eun; Lee, Suji; Oh, Jin Kyoung; Jeong, Hyeonseok S; Cho, Hanbyul; Kim, Myeong Ju; Kim, Tammy D; Choi, Soo Hyun; Lim, Soo Mee; Lyoo, In Kyoon; Yoon, Sujung

2018-05-10

The degree and salience of pain have been known to be constantly monitored and modulated by the brain. In the case of maladaptive neural responses as reported in centralized pain conditions such as complex regional pain syndrome (CRPS), the perception of pain is amplified and remains elevated even without sustained peripheral pain inputs. Given that the attentional state of the brain greatly influences the perception and interpretation of pain, we investigated the role of the attention network and its dynamic interactions with other pain-related networks of the brain in CRPS. We examined alterations in the intra- and inter-network functional connectivities in 21 individuals with CRPS and 49 controls. CRPS-related reduction in intra-network functional connectivity was found in the attention network. Individuals with CRPS had greater inter-network connectivities between the attention and salience networks as compared with healthy controls. Furthermore, individuals within the CRPS group with high levels of pain catastrophizing showed greater inter-network connectivities between the attention and salience networks. Taken together, the current findings suggest that these altered connectivities may be potentially associated with the maladaptive pain coping as found in CRPS patients.

Intensity Modulation: A Novel Approach to Percept Control in Spinal Cord Stimulation.

PubMed

Tan, Daniel; Tyler, Dustin; Sweet, Jennifer; Miller, Jonathan

2016-04-01

Spinal cord stimulation (SCS) can be effective for neuropathic pain, but clinical benefit is sometimes inadequate or is offset by stimulation-induced side-effects, and response can be inconsistent among patients. Intensity-modulated stimulation (IMS) is an alternative to tonic stimulation (TS) that involves continuous variation of stimulation intensity in a sinusoidal pattern between two different values, sequentially activating distinct axonal populations to produce an effect that resembles natural physiological signals. The purpose of this study is to evaluate the effect of IMS on the clinical effect of SCS. Seven patients undergoing a percutaneous SCS trial for postlaminectomy syndrome were enrolled. Thresholds for perception, pain relief, and discomfort were measured and used to create patient-specific models of axonal activation and charge delivery for both TS and IMS. All participants underwent three two-min periods of blinded stimulation using TS, IMS, and placebo, and were asked to describe the effect on quality of the sensory percept and pain relief. All participants perceived IMS differently from placebo, and five noted significant differences from TS that resulted in a more comfortable sensation. TS was described as electric and tingling, whereas IMS was described as producing a focal area of deep pressure with a sense of motion away from that focus. The anatomic location of coverage was similar between the two forms of stimulation, although one participant reported better lower back coverage with IMS. Computer modeling revealed that, compared with TS, IMS involved 36.4% less charge delivery and produced 78.7% less suprathreshold axonal activation. IMS for SCS is feasible, produces a more comfortable percept than conventional TS, and appears to provide a similar degree of pain relief with significantly lower energy requirements. Further studies are necessary to determine whether this represents an effective alternative to tonic SCS for treatment of neuropathic pain. © 2015 International Neuromodulation Society.

Intergroup relationships do not reduce racial bias in empathic neural responses to pain.

PubMed

Contreras-Huerta, Luis Sebastian; Hielscher, Emily; Sherwell, Chase S; Rens, Natalie; Cunnington, Ross

2014-11-01

Perceiving the pain of others activates similar neural structures to those involved in the direct experience of pain, including sensory and affective-motivational areas. Empathic responses can be modulated by race, such that stronger neural activation is elicited by the perception of pain in people of the same race compared with another race. In the present study, we aimed to identify when racial bias occurs in the time course of neural empathic responses to pain. We also investigated whether group affiliation could modulate the race effect. Using the minimal group paradigm, we assigned participants to one of two mixed-race teams. We examined event-related potentials from participants when viewing members of their own and the other team receiving painful or non-painful touch. We identified a significant racial bias in early ERP components at N1 over frontal electrodes, where Painful stimuli elicited a greater negative shift relative to Non-Painful stimuli in response to own race faces only. A long latency empathic response was also found at P3, where there was significant differentiation between Painful and Non-Painful stimuli regardless of Race or Group. There was no evidence that empathy-related brain activity was modulated by minimal group manipulation. These results support a model of empathy for pain that consists of early, automatic bias towards own-race empathic responses and a later top-down cognitive evaluation that does not differentiate between races and may ultimately lead to unbiased behaviour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modulation of laser-evoked potentials and pain perception by transcutaneous electrical nerve stimulation (TENS): a placebo-controlled study in healthy volunteers.

PubMed

Vassal, François; Créac'h, C; Convers, Ph; Laurent, B; Garcia-Larrea, L; Peyron, R

2013-09-01

To investigate the effects of transcutaneous electrical nerve stimulation (TENS) on brain nociceptive responses (laser-evoked potentials, LEPs) and pain perception. Twenty healthy subjects were included. Nociceptive CO(2)-laser pulses were sequentially delivered to the dorsum of both feet. The amplitude of LEPs and nociceptive thresholds were collected in three consecutive conditions: T1: "sham" TENS (2 Hz/low-intensity) positioned heterotopically, over the left thigh; T2: "active" TENS (120 Hz/low-intensity) applied homotopically, over the left common peroneal nerve; and T3: "sham" TENS (replication of condition T1). Compared with "sham" TENS, "active" TENS significantly decreased the LEPs amplitude. This effect was observed exclusively when "active" TENS was applied ipsilaterally to the painful stimulus. Nociceptive thresholds increased with sessions in both limbs, but the increase observed during the "active" condition of TENS (T2) exceeded significantly that observed during the condition T3 only on the foot ipsilateral to TENS. Compared with a credible placebo TENS, high-frequency TENS induced a significant attenuation of both the acute pain and LEPs induced by noxious stimuli applied on the same dermatome. This modulation of subjective and objective concomitants of pain processing reflects a real neurophysiological TENS-related effect on nociceptive transmission. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Cultural modulation of the neural correlates of emotional pain perception: the role of other-focusedness.

PubMed

Cheon, Bobby K; Im, Dong-Mi; Harada, Tokiko; Kim, Ji-Sook; Mathur, Vani A; Scimeca, Jason M; Parrish, Todd B; Park, Hyunwook; Chiao, Joan Y

2013-06-01

Cultures vary in the extent to which they emphasize group members to habitually attend to the needs, perspectives, and internal experiences of others compared to the self. Here we examined the influence that collectivistic and individualistic cultural environments may play on the engagement of the neurobiological processes that underlie the perception and processing of emotional pain. Using cross-cultural fMRI, Korean and Caucasian-American participants passively viewed scenes of others in situations of emotional pain and distress. Regression analyses revealed that the value of other-focusedness was associated with heightened neural response within the affective pain matrix (i.e. anterior cingulate cortex and insula) to a greater extent for Korean relative to Caucasian-American participants. These findings suggest that mindsets promoting attunement to the subjective experience of others may be especially critical for pain-related and potentially empathic processing within collectivistic relative to individualistic cultural environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

Can brief measures effectively screen for pain and somatic malingering? Examination of the Modified Somatic Perception Questionnaire and Pain Disability Index.

PubMed

Crighton, Adam H; Wygant, Dustin B; Applegate, Kathryn C; Umlauf, Robert L; Granacher, Robert P

2014-09-01

Recent rise in fraudulent disability claims in the United States has resulted in psychologists being increasingly called upon to use psychological tests to determine whether disability claims based on psychological or somatic/pain complaints are legitimate. To examine two brief measures, Modified Somatic Perception Questionnaire (MSPQ) and the Pain Disability Index (PDI), and their ability to screen for malingering in relation to the Bianchini et al. criteria for malingered pain-related disability published in The Spine Journal (2005). Examined brief self-report measures between litigating and nonlitigating pain samples. We compared 144 disability litigants, predominantly presenting a history of musculoskeletal injuries with psychiatric overlay, with 167 nonlitigating pain patients who were predominantly in treatment for chronic back pain issues and other musculoskeletal conditions. Modified Somatic Perception Questionnaire, Pain Disability Index, Minnesota Multiphasic Personality Inventory-2 Restructured Form, Test of Memory Malingering, Letter Memory Test, Victoria Symptom Validity Test, Structured Interview of Reported Symptoms-second edition, Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders somatoform disorders module. We examined a sample of 144 individuals undergoing compensation-seeking evaluations in relation to 167 nonlitigating pain patients. Group differences on both the MSPQ and PDI were calculated, as well as sensitivities, specificities, and positive and negative predictive powers for both measures at selected cutoffs. The results suggest that both the MSPQ and PDI are useful to screen for pain malingering in forensic evaluations, especially the MSPQ, which performed the best in differentiating between the groups. Copyright © 2014 Elsevier Inc. All rights reserved.

Music modulation of pain perception and pain-related activity in the brain, brain stem, and spinal cord: a functional magnetic resonance imaging study.

PubMed

Dobek, Christine E; Beynon, Michaela E; Bosma, Rachael L; Stroman, Patrick W

2014-10-01

The oldest known method for relieving pain is music, and yet, to date, the underlying neural mechanisms have not been studied. Here, we investigate these neural mechanisms by applying a well-defined painful stimulus while participants listened to their favorite music or to no music. Neural responses in the brain, brain stem, and spinal cord were mapped with functional magnetic resonance imaging spanning the cortex, brain stem, and spinal cord. Subjective pain ratings were observed to be significantly lower when pain was administered with music than without music. The pain stimulus without music elicited neural activity in brain regions that are consistent with previous studies. Brain regions associated with pleasurable music listening included limbic, frontal, and auditory regions, when comparing music to non-music pain conditions. In addition, regions demonstrated activity indicative of descending pain modulation when contrasting the 2 conditions. These regions include the dorsolateral prefrontal cortex, periaqueductal gray matter, rostral ventromedial medulla, and dorsal gray matter of the spinal cord. This is the first imaging study to characterize the neural response of pain and how pain is mitigated by music, and it provides new insights into the neural mechanism of music-induced analgesia within the central nervous system. This article presents the first investigation of neural processes underlying music analgesia in human participants. Music modulates pain responses in the brain, brain stem, and spinal cord, and neural activity changes are consistent with engagement of the descending analgesia system. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

Viewing a needle pricking a hand that you perceive as yours enhances unpleasantness of pain.

PubMed

Höfle, Marion; Hauck, Michael; Engel, Andreas K; Senkowski, Daniel

2012-05-01

"Don't look and it won't hurt" is commonly heard advice when receiving an injection, which implies that observing needle pricks enhances pain perception. Throughout our lives, we repeatedly learn that sharp objects cause pain when penetrating our skin, but situational expectations, like information given by the clinician prior to an injection, may also influence how viewing needle pricks affects forthcoming pain. How both previous experiences and acute situational expectations related to viewing needle pricks modulate pain perception is unknown. We presented participants with video clips of a hand perceived as their own being either pricked by a needle or touched by a Q-tip, while concurrently applying painful or nonpainful electrical stimuli. Intensity and unpleasantness ratings, as well as pupil dilation responses, were monitored. Effects of situational expectations about the strength of electrical stimuli were investigated by manipulating the contingency between clips and electrical stimuli across experimental blocks. Participants were explicitly informed about the contingency. Intensity ratings of electrical stimuli were higher when a clip was associated with expectation of painful compared to nonpainful stimuli, suggesting that situational expectations about forthcoming pain bias perceived intensity. Unpleasantness ratings and pupil dilation responses were higher when participants viewed a needle prick, compared to when they viewed a Q-tip touch, suggesting that previous experiences with viewing needle pricks primarily act upon perceived unpleasantness. Thus, remote painful experiences with viewing needle pricks, together with information given prior to an injection, differentially shape the impact of viewing a needle prick on pain perception. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Pain assessment by continuous EEG: association between subjective perception of tonic pain and peak frequency of alpha oscillations during stimulation and at rest.

PubMed

Nir, Rony-Reuven; Sinai, Alon; Raz, Einat; Sprecher, Elliot; Yarnitsky, David

2010-07-16

Recordings of neurophysiological brain responses to noxious stimuli have been traditionally based on short stimuli, in the order of milliseconds, which induce distinct event-related potentials (ERPs). However, using such stimuli in the experimental setting is disadvantageous as they are too brief to faithfully simulate clinical pain. We aimed at utilizing continuous EEG to investigate the properties of peak alpha frequency (PAF) as an objective cortical measure associated with subjective perception of tonic pain. Five minute long continuous EEG was recorded in 18 healthy volunteers under: (i) resting-state; (ii) innocuous temperature; and (iii) psychophysically-anchored noxious temperature. Numerical pain scores (NPSs) collected during the application of tonic noxious stimuli were tested for correlation with peak frequencies of alpha power-curves derived from central, temporal and frontal electrodes. NPSs and PAFs remained stable throughout the recording conditions (RM-ANOVAs; Ps>0.51). In the noxious condition, PAFs obtained at the bilateral temporal scalp were correlated with NPSs (Ps<0.001). Moreover, resting-state PAFs recorded at the bilateral temporal scalp were correlated with NPSs reported during the noxious condition (Ps<0.01). These psychophysical-neurophysiological relations attest to the properties of PAF as a novel cortical objective measure of subjective perception of tonic pain. Moreover, resting-state PAFs might hold inherent pain modulation attributes, possibly enabling the prediction of individual responsiveness to prolonged pain. The relevance of PAF to the neural processing of tonic pain may indicate its potential to advance pain research as well as clinical pain characterization. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Hopes for the Future of Pain Control.

PubMed

Bannister, Kirsty; Kucharczyk, Mateusz; Dickenson, Anthony H

2017-12-01

Here we aim to present an accessible review of the pharmacological targets for pain management, and succinctly discuss the newest trends in pain therapy. A key task for current pain pharmacotherapy is the identification of receptors and channels orchestrating nociception. Notwithstanding peripheral alterations in the receptors and channels following pathophysiological events, the modulatory mechanisms in the central nervous system are also fundamental to the regulation of pain perception. Bridging preclinical and clinical studies of peripheral and central components of pain modulation, we present the different types of pain and relate these to pharmacological interventions. We firstly highlight the roles of several peripheral nociceptors, such as NGF, CGRP, sodium channels, and TRP-family channels that may become novel targets for therapies. In the central nervous system, the roles of calcium channels and gabapentinoids as well as NMDA receptors in generating excitability are covered including ideas on central sensitization. We then turn to central modulatory systems and discuss opioids and monoamines. We aim to explain the importance of central sensitization and the dialogue of the spinal circuits with the brain descending modulatory controls before discussing a mechanism-based effectiveness of antidepressants in pain therapy and their potential to modulate the descending controls. Emphasizing the roles of conditioned pain modulation and its animal's equivalent, diffuse noxious inhibitory controls, we discuss these unique descending modulations as a potential tool for understanding mechanisms in patients suffering from pain. Mechanism-based therapy is the key to picking the correct treatments and recent clinical studies using sensory symptoms of patients as surrogates for underlying mechanisms can be used to subgroup patients and reveal actions of drugs that may be lost when studying heterogenous groups of patients. Key advances in the understanding of basic pain principles will impact our thinking about therapy targets. The complexity of pain syndromes will require tailored pharmacological drugs, often in combination or through drugs with more than one action, and often psychotherapy, to fully control pain.

Analgesia and hyperalgesia from GABA-mediated modulation of the cerebral cortex.

PubMed

Jasmin, Luc; Rabkin, Samuel D; Granato, Alberto; Boudah, Abdennacer; Ohara, Peter T

2003-07-17

It is known that pain perception can be altered by mood, attention and cognition, or by direct stimulation of the cerebral cortex, but we know little of the neural mechanisms underlying the cortical modulation of pain. One of the few cortical areas consistently activated by painful stimuli is the rostral agranular insular cortex (RAIC) where, as in other parts of the cortex, the neurotransmitter gamma-aminobutyric acid (GABA) robustly inhibits neuronal activity. Here we show that changes in GABA neurotransmission in the RAIC can raise or lower the pain threshold--producing analgesia or hyperalgesia, respectively--in freely moving rats. Locally increasing GABA, by using an enzyme inhibitor or gene transfer mediated by a viral vector, produces lasting analgesia by enhancing the descending inhibition of spinal nociceptive neurons. Selectively activating GABA(B)-receptor-bearing RAIC neurons produces hyperalgesia through projections to the amygdala, an area involved in pain and fear. Whereas most studies focus on the role of the cerebral cortex as the end point of nociceptive processing, we suggest that cerebral cortex activity can change the set-point of pain threshold in a top-down manner.

The effect of deep and slow breathing on pain perception, autonomic activity, and mood processing--an experimental study.

PubMed

Busch, Volker; Magerl, Walter; Kern, Uwe; Haas, Joachim; Hajak, Göran; Eichhammer, Peter

2012-02-01

Deep and slow breathing (DSB) techniques, as a component of various relaxation techniques, have been reported as complementary approaches in the treatment of chronic pain syndromes, but the relevance of relaxation for alleviating pain during a breathing intervention was not evaluated so far. In order to disentangle the effects of relaxation and respiration, we investigated two different DSB techniques at the same respiration rates and depths on pain perception, autonomic activity, and mood in 16 healthy subjects. In the attentive DSB intervention, subjects were asked to breathe guided by a respiratory feedback task requiring a high degree of concentration and constant attention. In the relaxing DSB intervention, the subjects relaxed during the breathing training. The skin conductance levels, indicating sympathetic tone, were measured during the breathing maneuvers. Thermal detection and pain thresholds for cold and hot stimuli and profile of mood states were examined before and after the breathing sessions. The mean detection and pain thresholds showed a significant increase resulting from the relaxing DSB, whereas no significant changes of these thresholds were found associated with the attentive DSB. The mean skin conductance levels indicating sympathetic activity decreased significantly during the relaxing DSB intervention but not during the attentive DSB. Both breathing interventions showed similar reductions in negative feelings (tension, anger, and depression). Our results suggest that the way of breathing decisively influences autonomic and pain processing, thereby identifying DSB in concert with relaxation as the essential feature in the modulation of sympathetic arousal and pain perception. Wiley Periodicals, Inc.

Endogenous Pain Modulation Induced by Extrinsic and Intrinsic Psychological Threat in Healthy Individuals.

PubMed

Gibson, William; Moss, Penny; Cheng, Tak Ho; Garnier, Alexandre; Wright, Anthony; Wand, Benedict M

2018-03-01

Many factors interact to influence threat perception and the subsequent experience of pain. This study investigated the effect of observing pain (extrinsic threat) and intrinsic threat of pain to oneself on pressure pain threshold (PPT). Forty socially connected pairs of healthy volunteers were threat-primed and randomly allocated to experimental or control roles. An experimental pain modulation paradigm was applied, with non-nociceptive threat cues used as conditioning stimuli. In substudy 1, the extrinsic threat to the experimental participant was observation of the control partner in pain. The control participant underwent hand immersion in noxious and non-noxious water baths in randomized order. Change in the observing participant's PPT from baseline to mid- and postimmersion was calculated. A significant interaction was found for PPT between conditions and test time (F 2,78  = 24.9, P < .005). PPT increased by 23.6% ± 19.3% between baseline and during hand immersion (F 1,39  = 43.7, P < .005). Substudy 2 investigated threat of imminent pain to self. After a 15-minute break, the experimental participant's PPT was retested ("baseline 2"). Threat was primed by suggestion of whole arm immersion in an icier, larger water bath. PPT was tested immediately before anticipated arm immersion, after which the experiment ended. A significant increase in PPT between "baseline 2" and "pre-immersion" was seen (t = -7.6, P = .005), a pain modulatory effect of 25.8 ± 20.7%. Extrinsic and intrinsic threat of pain, in the absence of any afferent input therefore influences pain modulation. This may need to be considered in studies that use noxious afferent input with populations who show dysfunctional pain modulation. The effect on endogenous analgesia of observing another's pain and of threat of pain to oneself was investigated. Extrinsic as well as intrinsic threat cues, in the absence of any afferent input, increased pain thresholds, suggesting that mere threat of pain may initiate analgesic effects in traditional noxious experimental paradigms. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Spatially defined modulation of skin temperature and hand ownership of both hands in patients with unilateral complex regional pain syndrome.

PubMed

Moseley, G Lorimer; Gallace, Alberto; Iannetti, Gian Domenico

2012-12-01

Numerous clinical conditions, including complex regional pain syndrome, are characterized by autonomic dysfunctions (e.g. altered thermoregulation, sometimes confined to a single limb), and disrupted cortical representation of the body and the surrounding space. The presence, in patients with complex regional pain syndrome, of a disruption in spatial perception, bodily ownership and thermoregulation led us to hypothesize that impaired spatial perception might result in a spatial-dependent modulation of thermoregulation and bodily ownership over the affected limb. In five experiments involving a total of 23 patients with complex regional pain syndrome of one arm and 10 healthy control subjects, we measured skin temperature of the hand with infrared thermal imaging, before and after experimental periods of either 9 or 10 min each, during which the hand was held on one or the other side of the body midline. Tactile processing was assessed by temporal order judgements of pairs of vibrotactile stimuli, delivered one to each hand. Pain and sense of ownership over the hand were assessed by self-report scales. Across experiments, when kept on its usual side of the body midline, the affected hand was 0.5 ± 0.3°C cooler than the healthy hand (P < 0.02 for all, a common finding in cold-type complex regional pain syndrome), and tactile stimuli delivered to the healthy hand were prioritized over those delivered to the affected hand. Simply crossing both hands over the midline resulted in (i) warming of the affected hand (the affected hand became 0.4 ± 0.3°C warmer than when it was in the uncrossed position; P = 0.01); (ii) cooling of the healthy hand (by 0.3 ± 0.3°C; P = 0.02); and (iii) reversal of the prioritization of tactile processing. When only the affected hand was crossed over the midline, it became warmer (by 0.5 ± 0.3°C; P = 0.01). When only the healthy hand was crossed over the midline, it became cooler (by 0.3 ± 0.3°C; P = 0.01). The temperature change of either hand was positively related to its distance from the body midline (pooled data: r = 0.76, P < 0.001). Crossing the affected hand over the body midline had small but significant effects on both spontaneous pain (which was reduced) and the sense of ownership over the hand (which was increased) (P < 0.04 for both). We conclude that impaired spatial perception modulated temperature of the limbs, tactile processing, spontaneous pain and the sense of ownership over the hands. These results show that complex regional pain syndrome involves more complex neurological dysfunction than has previously been considered.

Subliminal presentation of other faces (but not own face) primes behavioral and evoked cortical processing of empathy for pain.

PubMed

Ibáñez, Agustín; Hurtado, Esteban; Lobos, Alejandro; Escobar, Josefina; Trujillo, Natalia; Baez, Sandra; Huepe, David; Manes, Facundo; Decety, Jean

2011-06-29

Current research on empathy for pain emphasizes the overlap in the neural response between the first-hand experience of pain and its perception in others. However, recent studies suggest that the perception of the pain of others may reflect the processing of a threat or negative arousal rather than an automatic pro-social response. It can thus be suggested that pain processing of other-related, but not self-related, information could imply danger rather than empathy, due to the possible threat represented in the expressions of others (especially if associated with pain stimuli). To test this hypothesis, two experiments considering subliminal stimuli were designed. In Experiment 1, neutral and semantic pain expressions previously primed with own or other faces were presented to participants. When other-face priming was used, only the detection of semantic pain expressions was facilitated. In Experiment 2, pictures with pain and neutral scenarios previously used in ERP and fMRI research were used in a categorization task. Those pictures were primed with own or other faces following the same procedure as in Experiment 1 while ERPs were recorded. Early (N1) and late (P3) cortical responses between pain and no-pain were modulated only in the other-face priming condition. These results support the threat value of pain hypothesis and suggest the necessity for the inclusion of own- versus other-related information in future empathy for pain research. Copyright © 2011 Elsevier B.V. All rights reserved.

Meditation reduces pain-related neural activity in the anterior cingulate cortex, insula, secondary somatosensory cortex, and thalamus

PubMed Central

Nakata, Hiroki; Sakamoto, Kiwako; Kakigi, Ryusuke

2014-01-01

Recent studies have shown that meditation inhibits or relieves pain perception. To clarify the underlying mechanisms for this phenomenon, neuroimaging methods, such as functional magnetic resonance imaging, and neurophysiological methods, such as magnetoencephalography and electroencephalography, have been used. However, it has been difficult to interpret the results, because there is some paradoxical evidence. For example, some studies reported increased neural responses to pain stimulation during meditation in the anterior cingulate cortex (ACC) and insula, whereas others showed a decrease in these regions. There have been inconsistent findings to date. Moreover, in general, since the activities of the ACC and insula are correlated with pain perception, the increase in neural activities during meditation would be related to the enhancement of pain perception rather than its reduction. These contradictions might directly contribute to the ‘mystery of meditation.’ In this review, we presented previous findings for brain regions during meditation and the anatomical changes that occurred in the brain with long-term meditation training. We then discussed the findings of previous studies that examined pain-related neural activity during meditation. We also described the brain mechanisms responsible for pain relief during meditation, and possible reasons for paradoxical evidence among previous studies. By thoroughly overviewing previous findings, we hypothesized that meditation reduces pain-related neural activity in the ACC, insula, secondary somatosensory cortex, and thalamus. We suggest that the characteristics of the modulation of this activity may depend on the kind of meditation and/or number of years of experience of meditation, which were associated with paradoxical findings among previous studies that investigated pain-related neural activities during meditation. PMID:25566158

Reduced Modulation of Pain in Older Adults After Isometric and Aerobic Exercise.

PubMed

Naugle, Kelly M; Naugle, Keith E; Riley, Joseph L

2016-06-01

Laboratory-based studies show that acute aerobic and isometric exercise reduces sensitivity to painful stimuli in young healthy individuals, indicative of a hypoalgesic response. However, little is known regarding the effect of aging on exercise-induced hypoalgesia (EIH). The purpose of this study was to examine age differences in EIH after submaximal isometric exercise and moderate and vigorous aerobic exercise. Healthy older and younger adults completed 1 training session and 4 testing sessions consisting of a submaximal isometric handgrip exercise, vigorous or moderate intensity stationary cycling, or quiet rest (control). The following measures were taken before and after exercise/quiet rest: 1) pressure pain thresholds, 2) suprathreshold pressure pain ratings, 3) pain ratings during 30 seconds of prolonged noxious heat stimulation, and 4) temporal summation of heat pain. The results revealed age differences in EIH after isometric and aerobic exercise, with younger adults experiencing greater EIH compared with older adults. The age differences in EIH varied across pain induction techniques and exercise type. These results provide evidence for abnormal pain modulation after acute exercise in older adults. This article enhances our understanding of the influence of a single bout of exercise on pain sensitivity and perception in healthy older compared with younger adults. This knowledge could help clinicians optimize exercise as a method of pain management. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Virtual patient training to improve reproductive health care for women with intellectual disabilities.

PubMed

Boyd, Sara E; Sanders, Carla L; Kleinert, Harold L; Huff, Marlene B; Lock, Sharon; Johnson, Stephanie; Clevenger, Kim; Bush, Nathania A; Van Dyke, Eileen; Clark, Tara L

2008-01-01

A multimedia virtual patient module, involving the case of a young woman with mild intellectual disabilities with a complaint of diffuse abdominal pain, was developed as a clinical training tool for students in health care professions. Primary objectives following use of the module included improved knowledge and reduced perception of difficulty in treating women's health patients with intellectual disabilities. The module was developed using an iterative, collaborative process of a core development team that included medical professionals, multimedia specialists, the parent of a child with intellectual disability, and a disability advocate. Over the course of the module, students were required to identify appropriate and effective clinician-patient interactions in addition to relevant medical and developmental concerns for this patient population. Pilot data from a sample of nursing, physician assistant, and medical students suggest that the module is an effective tool for both improving students' knowledge and reducing their perception of difficulty in providing care to women's health patients with intellectual disabilities.

Group III metabotropic glutamate receptors inhibit hyperalgesia in animal models of inflammation and neuropathic pain.

PubMed

Goudet, Cyril; Chapuy, Eric; Alloui, Abdelkrim; Acher, Francine; Pin, Jean-Philippe; Eschalier, Alain

2008-07-01

Glutamate plays a key role in modulation of nociceptive processing. This excitatory amino acid exerts its action through two distinct types of receptors, ionotropic and metabotropic glutamate receptors (mGluRs). Eight mGluRs have been identified and divided in three groups based on their sequence similarity, pharmacology and G-protein coupling. While the role of group I and II mGluRs is now well established, little is known about the part played by group III mGluRs in pain. In this work, we studied comparatively the involvement of spinal group III mGluR in modulation of acute, inflammatory and neuropathic pain. While intrathecal injection of ACPT-I, a selective group III mGluR agonist, failed to induce any change in vocalization thresholds of healthy animals submitted to mechanical or thermal stimuli, it dose-dependently inhibited the nociceptive behavior of rats submitted to the formalin test and the mechanical hyperalgesia associated with different animal models of inflammatory (carrageenan-treated and monoarthritic rats) or neuropathic pain (mononeuropathic and vincristine-treated rats). Similar effects were also observed following intrathecal injection of PHCCC, a positive allosteric modulator of mGlu4. Antihyperalgesia induced by ACPT-I was blocked either by LY341495, a nonselective antagonist of mGluR, by MAP4, a selective group III antagonist. This study provide new evidences supporting the role of spinal group III mGluRs in the modulation of pain perception in different pathological pain states of various etiologies but not in normal conditions. It more particularly highlights the specific involvement of mGlu4 in this process and may be a useful therapeutic approach to chronic pain treatment.

Spinal Manipulative Therapy Has an Immediate Effect on Thermal Pain Sensitivity in People With Low Back Pain: A Randomized Controlled Trial

PubMed Central

Bishop, Mark D.; Robinson, Michael E.; Zeppieri, Giorgio; George, Steven Z.

2009-01-01

Background Current evidence suggests that spinal manipulative therapy (SMT) is effective in the treatment of people with low back pain (LBP); however, the corresponding mechanisms are unknown. Hypoalgesia is associated with SMT and is suggestive of specific mechanisms. Objective The primary purpose of this study was to assess the immediate effects of SMT on thermal pain perception in people with LBP. A secondary purpose was to determine whether the resulting hypoalgesia was a local effect and whether psychological influences were associated with changes in pain perception. Design This study was a randomized controlled trial. Setting A sample of convenience was recruited from community and outpatient clinics. Participants Thirty-six people (10 men, 26 women) currently experiencing LBP participated in the study. The average age of the participants was 32.39 (SD=12.63) years, and the average duration of LBP was 221.79 (SD=365.37) weeks. Intervention and Measurements Baseline demographic and psychological measurements were obtained, followed by quantitative sensory testing to assess temporal summation and Aδ fiber–mediated pain perception. Next, participants were randomly assigned to ride a stationary bicycle, perform low back extension exercises, or receive SMT. Finally, the same quantitative sensory testing protocol was reassessed to determine the immediate effects of each intervention on thermal pain sensitivity. Results Hypoalgesia to Aδ fiber–mediated pain perception was not observed. Group-dependent hypoalgesia of temporal summation specific to the lumbar innervated region was observed. Pair-wise comparisons indicated significant hypoalgesia in participants who received SMT, but not in those who rode a stationary bicycle or performed low back extension exercises. Psychological factors did not significantly correlate with changes in temporal summation in participants who received SMT. Limitations Only immediate effects of SMT were measured, so the authors are unable to comment on whether the inhibition of temporal summation is a lasting effect. Furthermore, the authors are unable to comment on the relationship between their findings and changes in clinical pain. Conclusions Inhibition of Aδ fiber–mediated pain perception was similar for all groups. However, inhibition of temporal summation was observed only in participants receiving SMT, suggesting a modulation of dorsal horn excitability that was observed primarily in the lumbar innervated area. PMID:19797305

Perceptions of children and their parents about the pain experienced during their hospitalization and its impact on parents' quality of life.

PubMed

Matziou, Vasiliki; Vlachioti, Efrosini; Megapanou, Eustathia; Ntoumou, Agapi; Dionisakopoulou, Christina; Dimitriou, Vasia; Tsoumakas, Konstantinos; Matziou, Theodora; Perdikaris, Pantelis

2016-09-01

The aim of the study was to assess pain levels and perceptions concerning pain by both children and their parents during hospitalization, as well as the impact of that pain upon parents' quality of life. The sample of the study consisted of 92 pediatric cancer patients, 159 pediatric patients with musculoskeletal problems and one of their parents. The study was performed between November 2010 and May 2011. The Pediatric Pain Questionnaire (Parent Version) and the PedsQL-Family Impact Module were used for pain assessment and the quality of life by the parents. Young patients completed the pediatric version of the Pediatric Pain Questionnaire for the evaluation of pediatric pain. Pain was measured by using the Wong-Baker facial pain scale, included in both parent and child version of the Pediatric Pain Questionnaire. This rating scale is recommended for children 3 years and older. Young patients reported higher acute pain scores than their parents (z = -2.5, P = 0.011; 99% confidence interval: 0.008-0.013). Young patients with orthopedic disorders had higher acute and chronic pain scores in comparison to their parents' reports (z = -3.4, P = 0.001; 99% confidence interval: 0.000-0.001 and z = -2.3, P = 0.021; 99% confidence interval: 0.017-0.025, respectively). Girls reported higher pain scores than boys (z = -2.0, P = 0.047; 99% CI: 0.041-0.052). Parental reports tended to underestimated children's pain, especially acute pain. The sex of children, the age and the marital status affect the perceptions of both children and their parents about pain. The parental quality of life is affected especially when the pain is caused by life-threatening diseases such as cancer. However, it improves as the treatment of their children is completed with no complications. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Outcomes and perception of lung surgery with implementation of a patient video education module: a prospective cohort study.

PubMed

Crabtree, Traves D; Puri, Varun; Bell, Jennifer M; Bontumasi, Nicholas; Patterson, G Alexander; Kreisel, Daniel; Krupnick, Alexander Sasha; Meyers, Bryan F

2012-05-01

Although surgeons are constantly making efforts to improve efficiency of care, it is important to also optimize the patients' understanding and satisfaction with their surgical experience. We investigated the effect of a preoperative educational video on patient outcomes and perception of surgery. An educational video was developed outlining preoperative, operative, and postoperative expectations for patients undergoing pulmonary resection. A prospective study was conducted with 150 patients undergoing surgery with routine preoperative discussion (control group, January 2008 to June 2009) and 150 patients who were provided a supplemental video module (video or study group, September 2009 to October 2010) in addition to routine discussion. Demographics and outcomes data were recorded. Patients completed a pain survey (McGill Questionnaire) and a standardized patient satisfaction survey at discharge and within 1 month of operation. The groups were similar in sex, age, comorbidities, and forced expiratory volume, 1 second, % predicted. Length of hospital stay (5.19 ± 7.4 days vs 4.31 ± 4.3 days; p = 0.2) and hospital readmission rates (12 of 134 [9%] vs 5 of 103 [4.9%]; p = 0.3) were similar for the 2 groups. At discharge, patients in the study group reported less pain at rest (0.98 ± 0.09) vs controls (1.39 ± 0.11) (p = 0.01) with no difference in pain with lifting or coughing. Patients in the study group reported better overall satisfaction with their operation (2.14 ± 0.07 vs 1.85 ± 0.07; p = 0.02), believed they were better prepared (2.01 ± 0.07 vs 1.70 ± 0.06; p = 0.006), and reported less anxiety about the surgical experience (2.79 ± 0.10 vs 2.24 ± 0.09; p = 0.0001). Implementation of a pulmonary resection education module improves patient preparedness, relieves anxiety, and improves pain perception. Additional development and dissemination of a comprehensive education program can improve patients' experience with lung surgery and impact outcomes. Copyright © 2012 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Human Mendelian pain disorders: a key to discovery and validation of novel analgesics.

PubMed

Goldberg, Y P; Pimstone, S N; Namdari, R; Price, N; Cohen, C; Sherrington, R P; Hayden, M R

2012-10-01

We have utilized a novel application of human genetics, illuminating the important role that rare genetic disorders can play in the development of novel drugs that may be of relevance for the treatment of both rare and common diseases. By studying a very rare Mendelian disorder of absent pain perception, congenital indifference to pain, we have defined Nav1.7 (endocded by SCN9A) as a critical and novel target for analgesic development. Strong human validation has emerged with SCN9A gain-of-function mutations causing inherited erythromelalgia (IEM) and paroxysmal extreme pain disorder, both Mendelian disorder of spontaneous or easily evoked pain. Furthermore, variations in the Nav1.7 channel also modulate pain perception in healthy subjects as well as in painful conditions such as osteoarthritis and Parkinson disease. On the basis of this, we have developed a novel compound (XEN402) that exhibits potent, voltage-dependent block of Nav1.7. In a small pilot study, we showed that XEN402 blocks Nav1.7 mediated pain associated with IEM thereby demonstrating the use of rare genetic disorders with mutant target channels as a novel approach to rapid proof-of-concept. Our approach underscores the critical role that human genetics can play by illuminating novel and critical pathways pertinent for drug discovery. © 2012 John Wiley & Sons A/S.

Effects of Listening to Music versus Environmental Sounds in Passive and Active Situations on Levels of Pain and Fatigue in Fibromyalgia.

PubMed

Mercadíe, Lolita; Mick, Gérard; Guétin, Stéphane; Bigand, Emmanuel

2015-10-01

In fibromyalgia, pain symptoms such as hyperalgesia and allodynia are associated with fatigue. Mechanisms underlying such symptoms can be modulated by listening to pleasant music. We expected that listening to music, because of its emotional impact, would have a greater modulating effect on the perception of pain and fatigue in patients with fibromyalgia than listening to nonmusical sounds. To investigate this hypothesis, we carried out a 4-week study in which patients with fibromyalgia listened to either preselected musical pieces or environmental sounds when they experienced pain in active (while carrying out a physical activity) or passive (at rest) situations. Concomitant changes of pain and fatigue levels were evaluated. When patients listened to music or environmental sounds at rest, pain and fatigue levels were significantly reduced after 20 minutes of listening, with no difference of effect magnitude between the two stimuli. This improvement persisted 10 minutes after the end of the listening session. In active situations, pain did not increase in presence of the two stimuli. Contrary to our expectations, music and environmental sounds produced a similar relieving effect on pain and fatigue, with no benefit gained by listening to pleasant music over environmental sounds. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Effect of expectation on pain assessment of lower- and higher-intensity stimuli.

PubMed

Ružić, Valentina; Ivanec, Dragutin; Modić Stanke, Koraljka

2017-01-01

Pain modulation via expectation is a well-documented phenomenon. So far it has been shown that expectations about effectiveness of a certain treatment enhance the effectiveness of different analgesics and of drug-free pain treatments. Also, studies demonstrate that people assess same-intensity stimuli differently, depending on the experimentally induced expectations regarding the characteristics of the stimuli. Prolonged effect of expectation on pain perception and possible symmetry in conditions of lower- and higher-intensity stimuli is yet to be studied. Aim of this study is to determine the effect of expectation on the perception of pain experimentally induced by the series of higher- and lower-intensity stimuli. 192 healthy participants were assigned to four experimental groups differing by expectations regarding the intensity of painful stimuli series. Expectations of two groups were congruent with actual stimuli; one group expected and received lower-intensity stimuli and the other expected and received higher-intensity stimuli. Expectations of the remaining two groups were not congruent with actual stimuli; one group expected higher-intensity stimuli, but actually received lower-intensity stimuli while the other group expected lower-intensity stimuli, but in fact received higher-intensity ones. Each group received a series of 24 varied-intensity electrical stimuli rated by the participants on a 30° intensity scale. Expectation manipulation had statistically significant effect on pain intensity assessment. When expecting lower-intensity stimuli, the participants underestimated pain intensity and when expecting higher-intensity stimuli, they overestimated pain intensity. The effect size of expectations upon pain intensity assessment was equal for both lower- and higher-intensity stimuli. The obtained results imply that expectation manipulation can achieve the desired effect of decreasing or increasing both slight and more severe pain for a longer period of time. Manipulation via expectation before the stimuli series was proven to be effective for pain modulation in the entire series of stimuli which lasted around 10min. The results suggest a potential benefit of manipulating expectations to alleviate emerging pain, since the obtained effects are moderate to large. It seems that expectation effect is strong enough to "overcome" even the direct effect of stimulus intensity (at least in the low to moderate intensity range), which suggests potential benefits of verbal instructions even in rather painful stimuli. Copyright © 2016 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Activation of Corticostriatal Circuitry Relieves Chronic Neuropathic Pain

PubMed Central

Lee, Michelle; Manders, Toby R.; Eberle, Sarah E.; Su, Chen; D'amour, James; Yang, Runtao; Lin, Hau Yueh; Deisseroth, Karl; Froemke, Robert C.

2015-01-01

Neural circuits that determine the perception and modulation of pain remain poorly understood. The prefrontal cortex (PFC) provides top-down control of sensory and affective processes. While animal and human imaging studies have shown that the PFC is involved in pain regulation, its exact role in pain states remains incompletely understood. A key output target for the PFC is the nucleus accumbens (NAc), an important component of the reward circuitry. Interestingly, recent human imaging studies suggest that the projection from the PFC to the NAc is altered in chronic pain. The function of this corticostriatal projection in pain states, however, is not known. Here we show that optogenetic activation of the PFC produces strong antinociceptive effects in a rat model (spared nerve injury model) of persistent neuropathic pain. PFC activation also reduces the affective symptoms of pain. Furthermore, we show that this pain-relieving function of the PFC is likely mediated by projections to the NAc. Thus, our results support a novel role for corticostriatal circuitry in pain regulation. PMID:25834050

Gender differences in pain: do emotions play a role?

PubMed

Rhudy, Jamie L; Williams, Amy E

2005-12-01

Research suggests that the influence of gender on the processing and experience of pain is a result of several mechanisms. One mediating variable is emotion, which may modulate pain through an interaction of valence (pleasant-unpleasant) and arousal (calm-excited). This review examines whether gender differences in the experience and processing of emotion contribute to differences in the modulation and perception of pain. An English-language search of MEDLINE and PsycINFO was conducted from 1887 to May 2005. Additional literature was obtained from reference lists of articles retained in the initial search. Emotion appears to influence pain through a valence-by-arousal interaction. Specifically, negatively valenced emotions with low to moderate arousal (eg, anxiety) enhance pain, whereas negatively valenced emotions with high arousal (eg, fear) reduce pain. In contrast, positively valenced emotions always reduce pain, as long as minimal arousal is achieved. Some evidence suggests that women are more sensitive than men to threat-related stimuli and thus experience more negative affect than men. This would generally lead to enhanced pain perception in women. It is also possible that women are more likely than men to experience negative affect with high arousal (intense fear) and thus pain inhibition. However, the relatively lower base rate of intense negative emotions is not likely to contribute much to gender differences in pain. Evidence also suggests that men may be more sensitive to positive events, particularly sexual/erotic stimuli, which may lead to more positive emotion-induced pain reduction in men, relative to women. This review suggests that gender differences in the experience of pain may arise from differences in the experience and processing of emotion that, in turn, differentially alter pain processing. Specifically, the system associated with negative affect may be more attuned to threatening stimuli in women, and the system associated with positive affect may be more attuned to pleasurable stimuli in men. However, there is a paucity of research directly addressing this issue; much of the research on this topic has failed to test a comprehensive model of emotion, failed to use adequate manipulation checks, or failed to use within-subject experimental designs that control for intra- and interindividual differences. Therefore, it is concluded that additional research is warranted.

Pain-related anxiety influences pain perception differently in men and women: a quantitative sensory test across thermal pain modalities.

PubMed

Thibodeau, Michel A; Welch, Patrick G; Katz, Joel; Asmundson, Gordon J G

2013-03-01

The sexes differ with respect to perception of experimental pain. Anxiety influences pain perception more in men than in women; however, there lacks research exploring which anxiety constructs influence pain perception differentially between men and women. Furthermore, research examining whether depression is associated with pain perception differently between the sexes remains scant. The present investigation was designed to examine how trait anxiety, pain-related anxiety constructs (ie, fear of pain, pain-related anxiety, anxiety sensitivity), and depression are associated with pain perception between the sexes. A total of 95 nonclinical participants (55% women) completed measures assessing the constructs of interest and participated in quantitative sensory testing using heat and cold stimuli administered by a Medoc Pathway Pain and Sensory Evaluation System. The findings suggest that pain-related anxiety constructs, but not trait anxiety, are associated with pain perception. Furthermore, these constructs are associated with pain intensity ratings in men and pain tolerance levels in women. This contrasts with previous research suggesting that anxiety influences pain perception mostly or uniquely in men. Depression was not systematically associated with pain perception in either sex. Systematic relationships were not identified that allow conclusions regarding how fear of pain, pain-related anxiety, and anxiety sensitivity may contribute to pain perception differentially in men and women; however, anxiety sensitivity was associated with increased pain tolerance, a novel finding needing further examination. The results provide directions for future research and clinical endeavors and support that fear and anxiety are important features associated with hyperalgesia in both men and women. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Linking pain and the body: neural correlates of visually induced analgesia.

PubMed

Longo, Matthew R; Iannetti, Gian Domenico; Mancini, Flavia; Driver, Jon; Haggard, Patrick

2012-02-22

The visual context of seeing the body can reduce the experience of acute pain, producing a multisensory analgesia. Here we investigated the neural correlates of this "visually induced analgesia" using fMRI. We induced acute pain with an infrared laser while human participants looked either at their stimulated right hand or at another object. Behavioral results confirmed the expected analgesic effect of seeing the body, while fMRI results revealed an associated reduction of laser-induced activity in ipsilateral primary somatosensory cortex (SI) and contralateral operculoinsular cortex during the visual context of seeing the body. We further identified two known cortical networks activated by sensory stimulation: (1) a set of brain areas consistently activated by painful stimuli (the so-called "pain matrix"), and (2) an extensive set of posterior brain areas activated by the visual perception of the body ("visual body network"). Connectivity analyses via psychophysiological interactions revealed that the visual context of seeing the body increased effective connectivity (i.e., functional coupling) between posterior parietal nodes of the visual body network and the purported pain matrix. Increased connectivity with these posterior parietal nodes was seen for several pain-related regions, including somatosensory area SII, anterior and posterior insula, and anterior cingulate cortex. These findings suggest that visually induced analgesia does not involve an overall reduction of the cortical response elicited by laser stimulation, but is consequent to the interplay between the brain's pain network and a posterior network for body perception, resulting in modulation of the experience of pain.

Somatosensory nociceptive characteristics differentiate subgroups in people with chronic low back pain: a cluster analysis.

PubMed

Rabey, Martin; Slater, Helen; OʼSullivan, Peter; Beales, Darren; Smith, Anne

2015-10-01

The objectives of this study were to explore the existence of subgroups in a cohort with chronic low back pain (n = 294) based on the results of multimodal sensory testing and profile subgroups on demographic, psychological, lifestyle, and general health factors. Bedside (2-point discrimination, brush, vibration and pinprick perception, temporal summation on repeated monofilament stimulation) and laboratory (mechanical detection threshold, pressure, heat and cold pain thresholds, conditioned pain modulation) sensory testing were examined at wrist and lumbar sites. Data were entered into principal component analysis, and 5 component scores were entered into latent class analysis. Three clusters, with different sensory characteristics, were derived. Cluster 1 (31.9%) was characterised by average to high temperature and pressure pain sensitivity. Cluster 2 (52.0%) was characterised by average to high pressure pain sensitivity. Cluster 3 (16.0%) was characterised by low temperature and pressure pain sensitivity. Temporal summation occurred significantly more frequently in cluster 1. Subgroups were profiled on pain intensity, disability, depression, anxiety, stress, life events, fear avoidance, catastrophizing, perception of the low back region, comorbidities, body mass index, multiple pain sites, sleep, and activity levels. Clusters 1 and 2 had a significantly greater proportion of female participants and higher depression and sleep disturbance scores than cluster 3. The proportion of participants undertaking <300 minutes per week of moderate activity was significantly greater in cluster 1 than in clusters 2 and 3. Low back pain, therefore, does not appear to be homogeneous. Pain mechanisms relating to presentations of each subgroup were postulated. Future research may investigate prognoses and interventions tailored towards these subgroups.

Brain mediators of predictive cue effects on perceived pain

PubMed Central

Atlas, Lauren Y.; Bolger, Niall; Lindquist, Martin A.; Wager, Tor D.

2010-01-01

Information about upcoming pain strongly influences pain experience in experimental and clinical settings, but little is known about the brain mechanisms that link expectation and experience. To identify the pathways by which informational cues influence perception, analyses must jointly consider both the effects of cues on brain responses and the relationship between brain responses and changes in reported experience. Our task and analysis strategy were designed to test these relationships. Auditory cues elicited expectations for low or high painful thermal stimulation, and we assessed how cues influenced human subjects’ pain reports and BOLD fMRI responses to matched levels of noxious heat. We used multi-level mediation analysis to identify brain regions that 1) are modulated by predictive cues, 2) predict trial-to-trial variations in pain reports, and 3) formally mediate the relationship between cues and reported pain. Cues influenced heat-evoked responses in most canonical pain-processing regions, including both medial and lateral pain pathways. Effects on several regions correlated with pre-task expectations, suggesting that expectancy plays a prominent role. A subset of pain-processing regions, including anterior cingulate cortex, anterior insula, and thalamus, formally mediated cue effects on pain. Effects on these regions were in turn mediated by cue-evoked anticipatory activity in the medial orbitofrontal cortex (OFC) and ventral striatum, areas not previously directly implicated in nociception. These results suggest that activity in pain-processing regions reflects a combination of nociceptive input and top-down information related to expectations, and that anticipatory processes in OFC and striatum may play a key role in modulating pain processing. PMID:20881115

Associative fear learning and perceptual discrimination: a perceptual pathway in the development of chronic pain.

PubMed

Zaman, Jonas; Vlaeyen, Johan W S; Van Oudenhove, Lukas; Wiech, Katja; Van Diest, Ilse

2015-04-01

Recent neuropsychological theories emphasize the influence of maladaptive learning and memory processes on pain perception. However, the precise relationship between these processes as well as the underlying mechanisms remain poorly understood; especially the role of perceptual discrimination and its modulation by associative fear learning has received little attention so far. Experimental work with exteroceptive stimuli consistently points to effects of fear learning on perceptual discrimination acuity. In addition, clinical observations have revealed that in individuals with chronic pain perceptual discrimination is impaired, and that tactile discrimination training reduces pain. Based on these findings, we present a theoretical model of which the central tenet is that associative fear learning contributes to the development of chronic pain through impaired interoceptive and proprioceptive discrimination acuity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Neurophysiology of hypnosis.

PubMed

Vanhaudenhuyse, A; Laureys, S; Faymonville, M-E

2014-10-01

We here review behavioral, neuroimaging and electrophysiological studies of hypnosis as a state, as well as hypnosis as a tool to modulate brain responses to painful stimulations. Studies have shown that hypnotic processes modify internal (self awareness) as well as external (environmental awareness) brain networks. Brain mechanisms underlying the modulation of pain perception under hypnotic conditions involve cortical as well as subcortical areas including anterior cingulate and prefrontal cortices, basal ganglia and thalami. Combined with local anesthesia and conscious sedation in patients undergoing surgery, hypnosis is associated with improved peri- and postoperative comfort of patients and surgeons. Finally, hypnosis can be considered as a useful analogue for simulating conversion and dissociation symptoms in healthy subjects, permitting better characterization of these challenging disorders by producing clinically similar experiences. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Pharmacologic Modulation of Hand Pain in Osteoarthritis: A Double-Blind Placebo-Controlled Functional Magnetic Resonance Imaging Study Using Naproxen

PubMed Central

Sanders, Duncan; Krause, Kristina; O'Muircheartaigh, Jonathan; Thacker, Michael A; Huggins, John P; Vennart, William; Massat, Nathalie J; Choy, Ernest; Williams, Steven C R; Howard, Matthew A

2015-01-01

Objective In an attempt to shed light on management of chronic pain conditions, there has long been a desire to complement behavioral measures of pain perception with measures of underlying brain mechanisms. Using functional magnetic resonance imaging (fMRI), we undertook this study to investigate changes in brain activity following the administration of naproxen or placebo in patients with pain related to osteoarthritis (OA) of the carpometacarpal (CMC) joint. Methods A placebo-controlled, double-blind, 2-period crossover study was performed in 19 individuals with painful OA of the CMC joint of the right hand. Following placebo or naproxen treatment periods, a functionally relevant task was performed, and behavioral measures of the pain experience were collected in identical fMRI examinations. Voxelwise and a priori region of interest analyses were performed to detect between-period differences in brain activity. Results Significant reductions in brain activity following treatment with naproxen, compared to placebo, were observed in brain regions commonly associated with pain perception, including the bilateral primary somatosensory cortex, thalamus, and amygdala. Significant relationships between changes in perceived pain intensity and changes in brain activity were also observed in brain regions previously associated with pain intensity. Conclusion This study demonstrates the sensitivity of fMRI to detect the mechanisms underlying treatments of known efficacy. The data illustrate the enticing potential of fMRI as an adjunct to self-report for detecting early signals of efficacy of novel therapies, both pharmacologic and nonpharmacologic, in small numbers of individuals with persistent pain. PMID:25533872

The Role of Positive Traits and Pain Catastrophizing in Pain Perception

PubMed Central

Hood, Anna

2013-01-01

A variety of biological, psychological, and social factors interact to influence pain. This article focuses on two distinct, but connected, psychological factors—positive personality traits and pain catastrophizing—and their link with pain perception in healthy and clinical populations. First, we review the protective link between positive personality traits, such as optimism, hope, and self-efficacy, and pain perception. Second, we provide evidence of the well-established relationship between pain catastrophizing and pain perception and other related outcomes. Third, we outline the inverse relationship between positive traits and pain catastrophizing, and offer a model that explains the inverse link between positive traits and pain perception through lower pain catastrophizing. Finally, we discuss clinical practice recommendations based on the aforementioned relationships. PMID:23512722

Suppressive effect of electromagnetic field on analgesic activity of tramadol in rats.

PubMed

Bodera, P; Stankiewicz, W; Antkowiak, B; Paluch, M; Kieliszek, J; Sobiech, J; Zdanowski, R; Wojdas, A; Siwicki, A K; Skopińska-Rózewska, E

2012-01-01

The electromagnetic fields (EMFs) have been shown to alter animal and human behavior, such as directional orientation, learning, pain perception (nociception or analgesia) and anxiety-related behaviors. The aim of this study was to evaluate the influence of electromagnetic fields of high-frequency microwaves on pain perception and anti-nociceptive activity of tramadol (TRAM) - analgetic effective in the treatment of moderate to severe acute and chronic pain states. Electromagnetic fields exposures of a)1500 MHz frequency and b) modulated, 1800 MHz (which is identical to that generated by mobile phones) were applied. Paw withdrawal latency (PWL) to thermal stimulus was measured in vehicle or tramadol (TRAM) treated animals before and after 30, 60 and 90 minutes from injections. The differences in the level of pain (PWL) between control group and rats exposed to EMF alone in three measurements, were not observed. Tramadol alone significantly increased PWLs to thermal stimulus in comparison to vehicle results at 30 (p < 0.001) and 60 minutes (p < 0.05) after drug injection. EMF exposure of both frequencies transiently suppressed analgesic effect of tramadol, significantly reducing paw withdrawal latency in animals treated with this drug at 30 minutes from the drug injection.

Temporal changes in cortical activation during conditioned pain modulation (CPM), a LORETA study.

PubMed

Moont, Ruth; Crispel, Yonatan; Lev, Rina; Pud, Dorit; Yarnitsky, David

2011-07-01

For most healthy subjects, both subjective pain ratings and pain-evoked potentials are attenuated under conditioned pain modulation (CPM; formerly termed diffuse noxious inhibitory controls, or DNIC). Although essentially spinal-bulbar, this inhibition is under cortical control. This is the first study to observe temporal as well as spatial changes in cortical activations under CPM. Specifically, we aimed to investigate the interplay of areas involved in the perception and processing of pain and those involved in controlling descending inhibition. We examined brief consecutive poststimulus time windows of 50 ms using a method of source-localization from pain evoked potentials, sLORETA. This enabled determination of dynamic changes in localized cortical generators evoked by phasic noxious heat stimuli to the left volar forearm in healthy young males, with and without conditioning hot-water pain to the right hand. We found a CPM effect characterized by an initial increased activation in the orbitofrontal cortex (OFC) and amygdala at 250-300 ms poststimulus, which was correlated with the extent of psychophysical pain reduction. This was followed by reduced activations in the primary and secondary somatosensory cortices, supplementary motor area, posterior insula, and anterior cingulate cortex from 400 ms poststimulus. Our findings show that the prefrontal pain-controlling areas of OFC and amygdala increase their activity in parallel with subjective pain reduction under CPM, and that this increased activity occurs prior to reductions in activations of the pain sensory areas. In conclusion, achieving pain inhibition by the CPM process seems to be under control of the OFC and the amygdala. Copyright © 2011 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Ecological aspects of pain in sensory modulation disorder.

PubMed

Bar-Shalita, T; Deutsch, L; Honigman, L; Weissman-Fogel, I

2015-01-01

Sensory Modulation Disorder (SMD) interferes with the daily life participation of otherwise healthy individuals and is characterized by over-, under- or seeking responsiveness to naturally occurring sensory stimuli. Previous laboratory findings indicate pain hyper-sensitivity in SMD individuals suggesting CNS alteration in pain processing and modulation. However, laboratory studies lack ecological validity, and warrant clinical completion in order to elicit a sound understanding of the phenomenon studied. Thus, this study explored the association between sensory modulation and pain in a daily life context in a general population sample. Daily life context of pain and sensations were measured in 250 adults (aged 23-40 years; 49.6% males) using 4 self-report questionnaires: Pain Sensitivity Questionnaire (PSQ) and Pain Catastrophizing Scale (PCS) to evaluate the sensory and cognitive aspects of pain; the Sensory Responsiveness Questionnaire (SRQ) to appraise SMD; and the Short Form - 36 Health Survey, version 2 (SF36) to assess health related Quality of Life (QoL). Thirty two individuals (12.8%) were found with over-responsiveness type of SMD, forming the SOR-SMD group. While no group differences (SOR-SMD vs. Non-SMD) were found, low-to-moderate total sample correlations were demonstrated between the SRQ-Aversive sub-scale and i) PSQ total (r=0.31, p<0.01) and sub-scales scores (r=0.27-0.28, p<0.01), as well as ii) PCS total and the sub-scales of Rumination and Helplessness scores (r=0.15, p<0.05). PSQ total and sub-scale scores were more highly correlated with SRQ-Aversive in the SOR-SMD group (r=0.57-0.68, p=0.03-<0.01) compared to Non-SMD group. The Physical Health - Total score (but not the Mental Health - Total) of the SF36 was lower for the SOR-SMD group (p=0.03), mainly due to the difference in the Body pain sub-scale (p=0.04). Results suggest that SOR-SMD is strongly associated with the sensory aspect of pain but weakly associated with the cognitive aspect. This indicates that SMD co-occurs with daily pain sensitivity, thus reducing QoL, but less with the cognitive-catastrophizing manifestation of pain perception. Copyright © 2015 Elsevier Ltd. All rights reserved.

Conditioned Pain Modulation Is Associated with Common Polymorphisms in the Serotonin Transporter Gene

PubMed Central

Lindstedt, Fredrik; Berrebi, Jonathan; Greayer, Erik; Lonsdorf, Tina B.; Schalling, Martin; Ingvar, Martin; Kosek, Eva

2011-01-01

Background Variation in the serotonin transporter (5-HTT) gene (SLC6A4) has been shown to influence a wide range of affective processes. Low 5-HTT gene-expression has also been suggested to increase the risk of chronic pain. Conditioned pain modulation (CPM) - i.e. ‘pain inhibits pain’ - is impaired in chronic pain states and, reciprocally, aberrations of CPM may predict the development of chronic pain. Therefore we hypothesized that a common variation in the SLC6A4 is associated with inter-individual variation in CPM. Forty-five healthy subjects recruited on the basis of tri-allelic 5-HTTLPR genotype, with inferred high or low 5-HTT-expression, were included in a double-blind study. A submaximal-effort tourniquet test was used to provide a standardized degree of conditioning ischemic pain. Individualized noxious heat and pressure pain thresholds (PPTs) were used as subjective test-modalities and the nociceptive flexion reflex (NFR) was used to provide an objective neurophysiological window into spinal processing. Results The low, as compared to the high, 5-HTT-expressing group exhibited significantly reduced CPM-mediated pain inhibition for PPTs (p = 0.02) and heat-pain (p = 0.02). The CPM-mediated inhibition of the NFR, gauged by increases in NFR-threshold, did not differ significantly between groups (p = 0.75). Inhibition of PPTs and heat-pain were correlated (Spearman’s rho = 0.35, p = 0.02), whereas the NFR-threshold increase was not significantly correlated with degree of inhibition of these subjectively reported modalities. Conclusions Our results demonstrate the involvement of the tri-allelic 5-HTTLPR genotype in explaining clinically relevant inter-individual differences in pain perception and regulation. Our results also illustrate that shifts in NFR-thresholds do not necessarily correlate to the modulation of experienced pain. We discuss various possible mechanisms underlying these findings and suggest a role of regulation of 5-HT receptors along the neuraxis as a function of differential 5-HTT-expression. PMID:21464942

Virtual visual effect of hospital waiting room on pain modulation in healthy subjects and patients with chronic migraine.

PubMed

de Tommaso, Marina; Ricci, Katia; Laneve, Luigi; Savino, Nicola; Antonaci, Vincenzo; Livrea, Paolo

2013-01-01

Environmental context has an important impact on health and well being. We aimed to test the effects of a visual distraction induced by classical hospital waiting room (RH) versus an ideal room with a sea view (IH), both represented in virtual reality (VR), on subjective sensation and cortical responses induced by painful laser stimuli (LEPs) in healthy volunteers and patients with chronic migraine (CM). Sixteen CM and 16 controls underwent 62 channels LEPs from the right hand, during a fully immersive VR experience, where two types of waiting rooms were simulated. The RH simulated a classical hospital waiting room while the IH represented a room with sea viewing. CM patients showed a reduction of laser pain rating and vertex LEPs during the IH vision. The sLORETA analysis confirmed that in CM patients the two VR simulations induced a different modulation of bilateral parietal cortical areas (precuneus and superior parietal lobe), and superior frontal and cingulate girus, in respect to controls. The architectural context may interfere with pain perception, depending upon the status of subject. Many variables may change patients' outcome and support the use of VR technology to test the best conditions for their management.

Strengthening exercises improve symptoms and quality of life but do not change autonomic modulation in fibromyalgia: a randomized clinical trial.

PubMed

Gavi, Maria Bernadete Renoldi Oliveira; Vassalo, Dalton Valentin; Amaral, Fabian Tadeu; Macedo, Danielle Constância Felício; Gava, Pablo Lúcio; Dantas, Eduardo Miranda; Valim, Valéria

2014-01-01

Autonomic dysfunction is an important mechanism that could explain many symptoms observed in fibromyalgia (FM). Exercise is an effective treatment, with benefits potentially mediated through changes in autonomic modulation. Strengthening is one of the less studied exercises in FM, and the acute and chronic effects of strengthening on the autonomic system remain unknown. The objective of this study was to assess the chronic effects of strengthening exercises (STRE) on autonomic modulation, pain perception and the quality of life (QOL) of FM patients. Eighty sedentary women with FM (ACR 1990) were randomly selected to participate in STRE or flexibility (FLEX) exercises in a blinded controlled trial. The intensity of STRE was set at 45% of the estimated load of 1 Repetition Maximum (RM) in 12 different exercises. Outcomes were Visual Analog Scale (VAS) for pain, Heart Rate Variability (HRV) analysis, treadmill test, the sit and reach test (Wells and Dillon's Bench), maximal repetitions test and handgrip dynamometry; and quality of life by the Fibromyalgia Impact Questionnaire (FIQ), the Beck and Idate Trait-State Inventory (IDATE), a short-form health survey (SF-36). The STRE group was more effective to strength gain for all muscles and pain control after 4 and 16 weeks (p<0.05). The FLEX group showed higher improvements in anxiety (p<0.05). Both groups showed improvements in the QOL, and there was no significant difference observed between the groups. There was no change in the HRV of the STRE and FLEX groups. Strengthening exercises show greater and more rapid improvements in pain and strength than flexibility exercises. Despite the benefits in fitness, pain, depression, anxiety and quality of life, no effect was observed on the autonomic modulation in both groups. This observation suggests that changes in autonomic modulation are not a target tobe clinically achieved in fibromyalgia. ClinicalTrials.gov NCT02004405.

Changes of Pain Perception, Autonomic Function, and Endocrine Parameters during Treatment of Anorectic Adolescents

ERIC Educational Resources Information Center

Bar, Karl-Jurgen; Boettger, Silke; Wagner, Gerd; Wilsdorf, Christine; Gerhard, Uwe Jens; Boettger, Michael K.; Blanz, Bernhard; Sauer, Heinrich

2006-01-01

Objectives: The underlying mechanisms of reduced pain perception in anorexia nervosa (AN) are unknown. To gain more insight into the pathology, the authors investigated pain perception, autonomic function, and endocrine parameters before and during successful treatment of adolescent AN patients. Method: Heat pain perception was assessed in 15…

Anticipation of electric shocks modulates low beta power and event-related fields during memory encoding.

PubMed

Bauch, Eva M; Bunzeck, Nico

2015-09-01

In humans, the temporal and oscillatory dynamics of pain anticipation and its effects on long-term memory are largely unknown. Here, we investigated this open question by using a previously established behavioral paradigm in combination with magnetoencephalography (MEG). Healthy human subjects encoded a series of scene images, which was combined with cues predicting an aversive electric shock with different probabilities (0.2, 0.5 or 0.8). After encoding, memory for the studied images was tested using a remember/know recognition task. Behaviorally, pain anticipation did not modulate recollection-based recognition memory per se, but interacted with the perceived unpleasantness of the electric shock [visual analogue scale rating from 1 (not unpleasant) to 10 (highly unpleasant)]. More precisely, the relationship between pain anticipation and recollection followed an inverted u-shaped function the more unpleasant the shocks were rated by a subject. At the physiological level, this quadratic effect was mimicked in the event-related magnetic fields associated with successful memory formation ('DM-effect') ∼450ms after image onset at left frontal sensors. Importantly, across all subjects, shock anticipation modulated oscillatory power in the low beta frequency range (13-20Hz) in a linear fashion at left temporal sensors. Taken together, our findings indicate that beta oscillations provide a generic mechanism underlying pain anticipation; the effect on subsequent long-term memory, on the other hand, is much more variable and depends on the level of individual pain perception. As such, our findings give new and important insights into how aversive motivational states can drive memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

The translocator protein gene is associated with symptom severity and cerebral pain processing in fibromyalgia.

PubMed

Kosek, Eva; Martinsen, Sofia; Gerdle, Björn; Mannerkorpi, Kaisa; Löfgren, Monika; Bileviciute-Ljungar, Indre; Fransson, Peter; Schalling, Martin; Ingvar, Martin; Ernberg, Malin; Jensen, Karin B

2016-11-01

The translocator protein (TSPO) is upregulated during glia activation in chronic pain patients. TSPO constitutes the rate-limiting step in neurosteroid synthesis, thus modulating synaptic transmission. Related serotonergic mechanisms influence if pro- or anti-nociceptive neurosteroids are produced. This study investigated the effects of a functional genetic polymorphism regulating the binding affinity to the TSPO, thus affecting symptom severity and cerebral pain processing in fibromyalgia patients. Gene-to-gene interactions with a functional polymorphism of the serotonin transporter gene were assessed. Fibromyalgia patients (n=126) were genotyped regarding the polymorphisms of the TSPO (rs6971) and the serotonin transporter (5-HTTLPR/rs25531). Functional magnetic resonance imaging (n=24) was used to study brain activation during individually calibrated pressure pain. Compared to mixed/low TSPO affinity binders, the high TSPO affinity binders rated more severe pain (p=0.016) and fibromyalgia symptoms (p=0.02). A significant interaction was found between the TSPO and the serotonin transporter polymorphisms regarding pain severity (p<0.0001). Functional connectivity analyses revealed that the TSPO high affinity binding group had more pronounced pain-evoked functional connectivity in the right frontoparietal network, between the dorsolateral prefrontal area and the parietal cortex. In conclusion, fibromyalgia patients with the TSPO high affinity binding genotype reported a higher pain intensity and more severe fibromyalgia symptoms compared to mixed/low affinity binders, and this was modulated by interaction with the serotonin transporter gene. To our knowledge this is the first evidence of functional genetic polymorphisms affecting pain severity in FM and our findings are in line with proposed glia-related mechanisms. Furthermore, the functional magnetic resonance findings indicated an effect of translocator protein on the affective-motivational components of pain perception. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Facing the experience of pain: A neuropsychological perspective

NASA Astrophysics Data System (ADS)

Fabbro, Franco; Crescentini, Cristiano

2014-09-01

Pain is an experience that none of us would like to have but that each one of us is destined to experience in our lives. Despite its pervasiveness, the experience of pain remains problematic and complex in its depth. Pain is a multidimensional experience that involves nociception as well as emotional and cognitive aspects that can modulate its perception. Following a brief discussion of the neurobiological mechanisms underlying pain, the purpose of this review is to discuss the main psychological, neuropsychological, cultural, and existential aspects which are the basis of diverse forms of pain, like the pain of separation from caregivers or from ourselves (e.g., connected to the thought of our death), the suffering that we experience observing other people's pain, the pain of change and the existential pain connected to the temporal dimension of the mind. Finally, after a discussion of how the mind is able to not only create but also alleviate the pain, through mechanisms such as the expectation of the treatment and the hope of healing, we conclude by discussing neuropsychological research data and the attitude promoted by mindfulness meditation in relation to the pain. An attitude in which, instead to avoid and reject the pain, one learns to face mindfully the experience of pain.

Facing the experience of pain: a neuropsychological perspective.

PubMed

Fabbro, Franco; Crescentini, Cristiano

2014-09-01

Pain is an experience that none of us would like to have but that each one of us is destined to experience in our lives. Despite its pervasiveness, the experience of pain remains problematic and complex in its depth. Pain is a multidimensional experience that involves nociception as well as emotional and cognitive aspects that can modulate its perception. Following a brief discussion of the neurobiological mechanisms underlying pain, the purpose of this review is to discuss the main psychological, neuropsychological, cultural, and existential aspects which are the basis of diverse forms of pain, like the pain of separation from caregivers or from ourselves (e.g., connected to the thought of our death), the suffering that we experience observing other people's pain, the pain of change and the existential pain connected to the temporal dimension of the mind. Finally, after a discussion of how the mind is able to not only create but also alleviate the pain, through mechanisms such as the expectation of the treatment and the hope of healing, we conclude by discussing neuropsychological research data and the attitude promoted by mindfulness meditation in relation to the pain. An attitude in which, instead to avoid and reject the pain, one learns to face mindfully the experience of pain. Copyright © 2013 Elsevier B.V. All rights reserved.

Low-frequency brain stimulation to the left dorsolateral prefrontal cortex increases the negative impact of social exclusion among those high in personal distress.

PubMed

Fitzgibbon, Bernadette Mary; Kirkovski, Melissa; Bailey, Neil Wayne; Thomson, Richard Hilton; Eisenberger, Naomi; Enticott, Peter Gregory; Fitzgerald, Paul Bernard

2017-06-01

The dorsolateral prefrontal cortex (DLPFC) is thought to play a key role in the cognitive control of emotion and has therefore, unsurprisingly, been implicated in the regulation of physical pain perception. This brain region may also influence the experience of social pain, which has been shown to activate similar neural networks as seen in response to physical pain. Here, we applied sham or active low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC, previously shown to exert bilateral effects in pain perception, in healthy participants. Following stimulation, participants played the "Cyberball Task"; an online ball-tossing game in which the subject participant is included or excluded. Compared to sham, rTMS did not modulate behavioural response to social exclusion. However, within the active rTMS group only, greater trait personal distress was related to enhanced negative outcomes to social exclusion. These results add further support to the notion that the effect of brain stimulation is not homogenous across individuals, and indicates the need to consider baseline individual differences when assessing response to brain stimulation. This seems particularly relevant in social neuroscience investigations, where trait factors may have a meaningful effect.

Hypnotizability and Placebo Analgesia in Waking and Hypnosis as Modulators of Auditory Startle Responses in Healthy Women: An ERP Study.

PubMed

De Pascalis, Vilfredo; Scacchia, Paolo

2016-01-01

We evaluated the influence of hypnotizability, pain expectation, placebo analgesia in waking and hypnosis on tonic pain relief. We also investigated how placebo analgesia affects somatic responses (eye blink) and N100 and P200 waves of event-related potentials (ERPs) elicited by auditory startle probes. Although expectation plays an important role in placebo and hypnotic analgesia, the neural mechanisms underlying these treatments are still poorly understood. We used the cold cup test (CCT) to induce tonic pain in 53 healthy women. Placebo analgesia was initially produced by manipulation, in which the intensity of pain induced by the CCT was surreptitiously reduced after the administration of a sham analgesic cream. Participants were then tested in waking and hypnosis under three treatments: (1) resting (Baseline); (2) CCT-alone (Pain); and (3) CCT plus placebo cream for pain relief (Placebo). For each painful treatment, we assessed pain and distress ratings, eye blink responses, N100 and P200 amplitudes. We used LORETA analysis of N100 and P200 waves, as elicited by auditory startle, to identify cortical regions sensitive to pain reduction through placebo and hypnotic analgesia. Higher pain expectation was associated with higher pain reductions. In highly hypnotizable participants placebo treatment produced significant reductions of pain and distress perception in both waking and hypnosis condition. P200 wave, during placebo analgesia, was larger in the frontal left hemisphere while placebo analgesia, during hypnosis, involved the activity of the left hemisphere including the occipital region. These findings demonstrate that hypnosis and placebo analgesia are different processes of top-down regulation. Pain reduction was associated with larger EMG startle amplitudes, N100 and P200 responses, and enhanced activity within the frontal, parietal, and anterior and posterior cingulate gyres. LORETA results showed that placebo analgesia modulated pain-responsive areas known to reflect the ongoing pain experience.

Hypnotizability and Placebo Analgesia in Waking and Hypnosis as Modulators of Auditory Startle Responses in Healthy Women: An ERP Study

PubMed Central

De Pascalis, Vilfredo; Scacchia, Paolo

2016-01-01

We evaluated the influence of hypnotizability, pain expectation, placebo analgesia in waking and hypnosis on tonic pain relief. We also investigated how placebo analgesia affects somatic responses (eye blink) and N100 and P200 waves of event-related potentials (ERPs) elicited by auditory startle probes. Although expectation plays an important role in placebo and hypnotic analgesia, the neural mechanisms underlying these treatments are still poorly understood. We used the cold cup test (CCT) to induce tonic pain in 53 healthy women. Placebo analgesia was initially produced by manipulation, in which the intensity of pain induced by the CCT was surreptitiously reduced after the administration of a sham analgesic cream. Participants were then tested in waking and hypnosis under three treatments: (1) resting (Baseline); (2) CCT-alone (Pain); and (3) CCT plus placebo cream for pain relief (Placebo). For each painful treatment, we assessed pain and distress ratings, eye blink responses, N100 and P200 amplitudes. We used LORETA analysis of N100 and P200 waves, as elicited by auditory startle, to identify cortical regions sensitive to pain reduction through placebo and hypnotic analgesia. Higher pain expectation was associated with higher pain reductions. In highly hypnotizable participants placebo treatment produced significant reductions of pain and distress perception in both waking and hypnosis condition. P200 wave, during placebo analgesia, was larger in the frontal left hemisphere while placebo analgesia, during hypnosis, involved the activity of the left hemisphere including the occipital region. These findings demonstrate that hypnosis and placebo analgesia are different processes of top-down regulation. Pain reduction was associated with larger EMG startle amplitudes, N100 and P200 responses, and enhanced activity within the frontal, parietal, and anterior and posterior cingulate gyres. LORETA results showed that placebo analgesia modulated pain-responsive areas known to reflect the ongoing pain experience. PMID:27486748

Posttraumatic Stress Disorder, Orientation to Pain, and Pain Perception in Ex-Prisoners of War Who Underwent Torture.

PubMed

Tsur, Noga; Defrin, Ruth; Ginzburg, Karni

Studies suggest that torture survivors often experience long-term chronic pain and increased pain perception. However, it is unclear whether the actual experience of torture or rather the subsequent posttraumatic stress disorder (PTSD) explains these pain problems. Furthermore, although catastrophic and fearful orientations to pain have been suggested to play a significant role in the association between trauma and pain, the underlying mechanisms remain unclear. This study examined whether chronic pain and pain perception among torture survivors are associated with torture experience or PTSD and whether catastrophic and fearful orientations mediate or moderate these associations. Fifty-nine ex-prisoners of war who underwent torture and 44 matched veterans participated in this study. Pain perception was evaluated by assessing pain threshold and reactivity to experimental suprathreshold noxious stimuli. Participants completed self-administered questionnaires assessing PTSD, chronic pain, pain catastrophizing, and fear of pain. Although chronic pain was associated with PTSD (0.44 < β < 0.49, p < .002), increased pain perception was correlated with torture (0.33 < β < 0.65, p < .05). Pain catastrophizing was found to mediate the association between PTSD and chronic pain (β = 0.18 and 0.19, respectively; p < .05). Fear of pain moderated the association between torture and pain perception (β = 0.41 and 0.42, respectively; p < .017). The findings suggest that chronic pain is contingent upon the psychological toll of torture, that is, PTSD. This study also indicates that PTSD exacerbates catastrophic orientation, which in turn may amplify chronic pain. Reactivity to experimental noxious stimuli was related to previous experiences of torture, which enhances perceived pain intensity when interacting with a fearful pain orientation. These findings highlight the significance of orientation to bodily experiences after trauma.

Was it less painful for knights? Influence of appearance on pain perception.

PubMed

Weeth, A; Mühlberger, A; Shiban, Y

2017-11-01

Pain perception is a subjective experience shaped by different factors. In this study, we investigated the influence of a visually manipulated appearance of a virtual arm on pain perception. Specifically, we investigated how pain perception and vegetative skin responses were modified by inducing a virtual protection on the right arm by a virtual armour. Participants (n = 32) immersed in virtual reality embodied a virtual arm, which appeared in three different versions (uncovered, neutral or protected). During the virtual reality simulation, the participants received electrical stimulations of varying intensities. Skin conductance level (SCL) was analysed for the phase anticipation (from the moment the arm appeared until the electric stimulation) and perception of pain (after the electric stimulation). Pain ratings were acquired after the painful stimuli occurred. The sense of embodiment was positive for the unprotected and neutral condition and lower for the protected than for the neutral arm. Pain ratings were significantly decreased in the protected arm condition compared with both the unprotected arm and the neutral arm conditions. The SCL measurements showed no significant differences for the three arm types. According to the pain ratings, participants felt significantly less pain in the covered arm condition compared with the unprotected and the neutral arm condition. Subjective pain perception was decreased by a virtual protection of the arm in VR. The simplicity of the manipulation suggests possible practical uses in pain therapy by strengthening the patients' own capacities to influence their pain using simple cognitive manipulations via virtual reality. A virtual, covered arm causes differences in reported pain ratings. Physiological measurements do not confirm the findings. Visual information about body protection can have an impact on pain perception. © 2017 European Pain Federation - EFIC®.

Stress-Induced Chronic Visceral Pain of Gastrointestinal Origin

PubMed Central

Greenwood-Van Meerveld, Beverley; Johnson, Anthony C.

2017-01-01

Visceral pain is generally poorly localized and characterized by hypersensitivity to a stimulus such as organ distension. In concert with chronic visceral pain, there is a high comorbidity with stress-related psychiatric disorders including anxiety and depression. The mechanisms linking visceral pain with these overlapping comorbidities remain to be elucidated. Evidence suggests that long term stress facilitates pain perception and sensitizes pain pathways, leading to a feed-forward cycle promoting chronic visceral pain disorders such as irritable bowel syndrome (IBS). Early life stress (ELS) is a risk-factor for the development of IBS, however the mechanisms responsible for the persistent effects of ELS on visceral perception in adulthood remain incompletely understood. In rodent models, stress in adult animals induced by restraint and water avoidance has been employed to investigate the mechanisms of stress-induce pain. ELS models such as maternal separation, limited nesting, or odor-shock conditioning, which attempt to model early childhood experiences such as neglect, poverty, or an abusive caregiver, can produce chronic, sexually dimorphic increases in visceral sensitivity in adulthood. Chronic visceral pain is a classic example of gene × environment interaction which results from maladaptive changes in neuronal circuitry leading to neuroplasticity and aberrant neuronal activity-induced signaling. One potential mechanism underlying the persistent effects of stress on visceral sensitivity could be epigenetic modulation of gene expression. While there are relatively few studies examining epigenetically mediated mechanisms involved in visceral nociception, stress-induced visceral pain has been linked to alterations in DNA methylation and histone acetylation patterns within the brain, leading to increased expression of pro-nociceptive neurotransmitters. This review will discuss the potential neuronal pathways and mechanisms responsible for stress-induced exacerbation of chronic visceral pain. Additionally, we will review the importance of specific experimental models of adult stress and ELS in enhancing our understanding of the basic molecular mechanisms of pain processing. PMID:29213232

African Americans' Perceptions of Pain and Pain Management: A Systematic Review.

PubMed

Booker, Staja Q

2016-01-01

The purpose of this systematic review is to explore the perceptions of acute, persistent, and disease-specific pain and treatment options held by adult African Americans. Underassessment and undermanagement of pain in African Americans has been well documented; however, the cultural continuum of pain perceptions and their influence on pain assessment and management has not been synthesized. Electronic database searches of the Cumulative Index for Nursing and Allied Health Literature and PubMed, Web-based searches of the pain-specific journals plus a manual search of reference lists identified 41 relevant articles addressing perceptions of pain and/or pain management. Analysis of the literature revealed six themes: (a) meaning of pain, (b) description of pain, (c) coping with pain, (d) impact of pain, (e) patient-provider relationship, and (f) treatment approaches. These findings warrant further research and indicate the need for more precise evaluation of pain in African Americans, highlighting an imperative to incorporate cultural patterns into pain management practice and education. © The Author(s) 2014.

Thoughts of Death Modulate Psychophysical and Cortical Responses to Threatening Stimuli

PubMed Central

Valentini, Elia; Koch, Katharina; Aglioti, Salvatore Maria

2014-01-01

Existential social psychology studies show that awareness of one's eventual death profoundly influences human cognition and behaviour by inducing defensive reactions against end-of-life related anxiety. Much less is known about the impact of reminders of mortality on brain activity. Therefore we explored whether reminders of mortality influence subjective ratings of intensity and threat of auditory and painful thermal stimuli and the associated electroencephalographic activity. Moreover, we explored whether personality and demographics modulate psychophysical and neural changes related to mortality salience (MS). Following MS induction, a specific increase in ratings of intensity and threat was found for both nociceptive and auditory stimuli. While MS did not have any specific effect on nociceptive and auditory evoked potentials, larger amplitude of theta oscillatory activity related to thermal nociceptive activity was found after thoughts of death were induced. MS thus exerted a top-down modulation on theta electroencephalographic oscillatory amplitude, specifically for brain activity triggered by painful thermal stimuli. This effect was higher in participants reporting higher threat perception, suggesting that inducing a death-related mind-set may have an influence on body-defence related somatosensory representations. PMID:25386905

Affective touch and attachment style modulate pain: a laser-evoked potentials study

PubMed Central

Drabek, Marianne M.; Paloyelis, Yannis; Fotopoulou, Aikaterini

2016-01-01

Affective touch and cutaneous pain are two sub-modalities of interoception with contrasting affective qualities (pleasantness/unpleasantness) and social meanings (care/harm), yet their direct relationship has not been investigated. In 50 women, taking into account individual attachment styles, we assessed the role of affective touch and particularly the contribution of the C tactile (CT) system in subjective and electrophysiological responses to noxious skin stimulation, namely N1 and N2-P2 laser-evoked potentials. When pleasant, slow (versus fast) velocity touch was administered to the (non-CT-containing) palm of the hand, higher attachment anxiety predicted increased subjective pain ratings, in the same direction as changes in N2 amplitude. By contrast, when pleasant touch was administered to CT-containing skin of the arm, higher attachment anxiety predicted attenuated N1 and N2 amplitudes. Higher attachment avoidance predicted opposite results. Thus, CT-based affective touch can modulate pain in early and late processing stages (N1 and N2 components), with the direction of effects depending on attachment style. Affective touch not involving the CT system seems to affect predominately the conscious perception of pain, possibly reflecting socio-cognitive factors further up the neurocognitive hierarchy. Affective touch may thus convey information about available social resources and gate pain responses depending on individual expectations of social support. This article is part of the themed issue ‘Interoception beyond homeostasis: affect, cognition and mental health’. PMID:28080967

Disrupted Self-Perception in People With Chronic Low Back Pain. Further Evaluation of the Fremantle Back Awareness Questionnaire.

PubMed

Wand, Benedict Martin; Catley, Mark Jon; Rabey, Martin Ian; O'Sullivan, Peter Bruce; O'Connell, Neil Edward; Smith, Anne Julia

2016-09-01

Several lines of evidence suggest that body perception is altered in people with chronic back pain. Maladaptive perceptual awareness of the back might contribute to the pain experience as well as serve as a target for treatment. The Fremantle Back Awareness Questionnaire (FreBAQ) is a simple questionnaire recently developed to assess back-specific altered self-perception. The aims of this study were to present the outcomes of a comprehensive evaluation of the questionnaire's psychometric properties and explore the potential relationships between body perception, nociceptive sensitivity, distress, and beliefs about back pain and the contribution these factors might play in explaining pain and disability. Two hundred fifty-one people with chronic back pain completed the questionnaire as well as a battery of clinical tests. The Rasch model was used to explore the questionnaires' psychometric properties and correlation and multiple linear regression analyses were used to explore the relationship between altered body perception and clinical status. The FreBAQ appears unidimensional with no redundant items, has minimal ceiling and floor effects, acceptable internal consistency, was functional on the category rating scale, and was not biased by demographic or clinical variables. FreBAQ scores were correlated with sensitivity, distress, and beliefs and were uniquely associated with pain and disability. Several lines of evidence suggest that body perception might be disturbed in people with chronic low back pain, possibly contributing to the condition and offering a potential target for treatment. The FreBAQ was developed as a quick and simple way of measuring back-specific body perception in people with chronic low back pain. The questionnaire appears to be a psychometrically sound way of assessing altered self-perception. The level of altered self-perception is positively correlated with pain intensity and disability as well as showing associations with psychological distress, pain catastrophization, fear avoidance beliefs, and lumbar pressure pain threshold. In this sample, it appears that altered self-perception might be a more important determinant of clinical severity than psychological distress, pain catastrophization, fear avoidance beliefs, or lumbar pressure pain threshold. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Seeing the body distorts tactile size perception.

PubMed

Longo, Matthew R; Sadibolova, Renata

2013-03-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception. Copyright © 2012 Elsevier B.V. All rights reserved.

Dopamine Precursor Depletion Influences Pain Affect Rather than Pain Sensation

PubMed Central

Schulz, Enrico; Baumkötter, Jochen; Ploner, Markus

2014-01-01

Pain is a multidimensional experience, which includes sensory, cognitive, and affective aspects. Converging lines of evidence indicate that dopaminergic neurotransmission plays an important role in human pain perception. However, the precise effects of dopamine on different aspects of pain perception remain to be elucidated. To address this question, we experimentally decreased dopaminergic neurotransmission in 22 healthy human subjects using Acute Phenylalanine and Tyrosine Depletion (APTD). During APTD and a control condition we applied brief painful laser stimuli to the hand, assessed different aspects of pain perception, and recorded electroencephalographic responses. APTD-induced decreases of cerebral dopaminergic activity did not influence sensory aspects of pain perception. In contrast, APTD yielded increases of pain unpleasantness. The increases of unpleasantness ratings positively correlated with effectiveness of APTD. Our finding of an influence of dopaminergic neurotransmission on affective but not sensory aspects of phasic pain suggests that analgesic effects of dopamine might be mediated by indirect effects on pain affect rather than by direct effects on ascending nociceptive signals. These findings contribute to our understanding of the complex relationship between dopamine and pain perception, which may play a role in various clinical pain states. PMID:24760082

Serotonin-1A Receptor Polymorphism (rs6295) Associated with Thermal Pain Perception

PubMed Central

Lindstedt, Fredrik; Karshikoff, Bianka; Schalling, Martin; Olgart Höglund, Caroline; Ingvar, Martin; Lekander, Mats; Kosek, Eva

2012-01-01

Background Serotonin (5-HT) is highly involved in pain regulation and serotonin-1A (5-HT1A) receptors are important in determining central 5-HT tone. Accordingly, variation in the 5-HT1A receptor gene (HTR1A) may contribute to inter-individual differences in human pain sensitivity. The minor G-allele of the HTR1A single nucleotide polymorphism (SNP) rs6295 attenuates firing of serotonergic neurons and reduces postsynaptic expression of the receptor. Experiments in rodents suggest that 5-HT1A-agonism modulates pain in opposite directions at mild compared to high noxious intensities. Based upon this and several other similar observations, we hypothesized that G-carriers would exhibit a relative hypoalgesia at mild thermal stimuli but tend towards hyperalgesia at higher noxious intensities. Methods Fourty-nine healthy individuals were selectively genotyped for rs6295. Heat- and cold-pain thresholds were assessed along with VAS-ratings of a range of suprathreshold noxious heat intensities (45°C–49°C). Nociceptive-flexion reflex (NFR) thresholds were also assessed. Results Volunteers did not deviate significantly from Hardy-Weinberg equilibrium. G-carriers were less sensitive to threshold-level thermal pain. This relative hypoalgesia was abolished at suprathreshold noxious intensities where G-carriers instead increased their ratings of heat-pain significantly more than C-homozygotes. No differences with regard to NFR-thresholds emerged. Conclusion/Significance To the best of our knowledge this is the first study of human pain perception on the basis of variation in HTR1A. The results illustrate the importance of including a range of stimulus intensities in assessments of pain sensitivity. In speculation, we propose that an attenuated serotonergic tone may be related to a ‘hypo- to hyperalgesic’ response-pattern. The involved mechanisms could be of clinical interest as variation in pain regulation is known to influence the risk of developing pain pathologies. Further investigations are therefore warranted. PMID:22952650

Racial bias in sport medical staff's perceptions of others' pain.

PubMed

Druckman, James N; Trawalter, Sophie; Montes, Ivonne; Fredendall, Alexandria; Kanter, Noah; Rubenstein, Allison Paige

2017-11-27

Unequal treatment based on race is well documented in higher education and healthcare settings. In the present work, we examine racial bias at the intersection of these domains: racial bias in pain-related perceptions among National Collegiate Athletic Association (NCAA) Division 1 sport medical staff. Using experimental vignettes about a student-athlete who injured his/her anterior cruciate ligament (ACL), we find, like prior work, that respondents perceived Black (vs. White) targets as having higher initial pain tolerance. Moreover, this bias was mediated by perceptions of social class. We extend prior work by showing racial bias was not evident on other outcome measures, including perception of recovery process pain, likelihood of over-reporting pain, and over-use of drugs to combat pain. This suggests stricter boundary conditions on bias in pain perceptions than had been previously recognized.

Orbitofrontal cortex mediates pain inhibition by monetary reward.

PubMed

Becker, Susanne; Gandhi, Wiebke; Pomares, Florence; Wager, Tor D; Schweinhardt, Petra

2017-04-01

Pleasurable stimuli, including reward, inhibit pain, but the level of the neuraxis at which they do so and the cerebral processes involved are unknown. Here, we characterized a brain circuitry mediating pain inhibition by reward. Twenty-four healthy participants underwent functional magnetic resonance imaging while playing a wheel of fortune game with simultaneous thermal pain stimuli and monetary wins or losses. As expected, winning decreased pain perception compared to losing. Inter-individual differences in pain modulation by monetary wins relative to losses correlated with activation in the medial orbitofrontal cortex (mOFC). When pain and reward occured simultaneously, mOFCs functional connectivity changed: the signal time course in the mOFC condition-dependent correlated negatively with the signal time courses in the rostral anterior insula, anterior-dorsal cingulate cortex and primary somatosensory cortex, which might signify moment-to-moment down-regulation of these regions by the mOFC. Monetary wins and losses did not change the magnitude of pain-related activation, including in regions that code perceived pain intensity when nociceptive input varies and/or receive direct nociceptive input. Pain inhibition by reward appears to involve brain regions not typically involved in nociceptive intensity coding but likely mediate changes in the significance and/or value of pain. © The Author (2017). Published by Oxford University Press.

Roller massage decreases spinal excitability to the soleus.

PubMed

Young, James D; Spence, Alyssa-Joy; Behm, David G

2018-04-01

Roller massage (RM) interventions have shown acute increases in range of motion (ROM) and pain pressure threshold (PPT). It is unclear whether the RM-induced increases can be attributed to changes in neural or muscle responses. The purpose of this study was to evaluate the effect of altered afferent input via application of RM on spinal excitability, as measured with the Hoffmann (H-) reflex. A randomized within-subjects design was used. Three 30-s bouts of RM were implemented on a rested, nonexercised, injury-free muscle with 30 s of rest between bouts. The researcher applied RM to the plantar flexors at three intensities of pain: high, moderate, and sham. Measures included normalized M-wave and H-reflex peak-to-peak amplitudes before, during, and up to 3 min postintervention. M-wave and H-reflex measures were highly reliable. RM resulted in significant decreases in soleus H-reflex amplitudes. High-intensity, moderate-intensity, and sham conditions decreased soleus H-reflex amplitudes by 58%, 43%, and 19%, respectively. H-reflexes induced with high-intensity rolling discomfort or pain were significantly lower than moderate and sham conditions. The effects were transient in nature, with an immediate return to baseline following RM. This is the first evidence of RM-induced modulation of spinal excitability. The intensity-dependent response observed indicates that rolling pressure or pain perception may play a role in modulation of the inhibition. Roller massage-induced neural modulation of spinal excitability may explain previously reported increases in ROM and PPT. NEW & NOTEWORTHY Recent evidence indicates that the benefits of foam rolling and roller massage are primarily accrued through neural mechanisms. The present study attempts to determine the neuromuscular response to roller massage interventions. We provide strong evidence of roller massage-induced neural modulation of spinal excitability to the soleus. It is plausible that reflex inhibition may explain subsequent increases in pain pressure threshold.

The efficacy of relaxation training on stress, anxiety, and pain perception in hemodialysis patients.

PubMed

Heidari Gorji, M A; Davanloo, A Abbaskhani; Heidarigorji, A M

2014-11-01

Patients on dialysis experience psychological distress, which can impact pain perception. Reduction of stress and anxiety in patients provides psychological resources to cope with their physical condition. We examined the efficacy of relaxation training on stress, anxiety, and pain perception of hemodialysis (HD) patients. eighty HD patients were randomized into two groups (intervention and control). Benson relaxation training was implemented in the intervention group for 15 min twice daily during 4 weeks. Pain perception, stress, and anxiety scale were evaluated before and after intervention. There were significant differences between pain perception, stress, and anxiety levels in case group before and after intervention (P < 0.001) and there was a correlation between pain perception with stress and anxiety. Instructing Benson's relaxation technique is accompanied by reducing pain, stress, and anxiety level of HD patients. Reducing stress and anxiety can provide calmness for the patients so that pursuing medical therapy would be accompanied with more tranquility and low pain intensity. We suggest improving and preventing the patients' psychological problems as well as other chronic disorders through applying nonpharmacological interventions.

Determining the longitudinal validity and meaningful differences in HRQL of the PedsQL™ Sickle Cell Disease Module.

PubMed

Panepinto, Julie A; Paul Scott, J; Badaki-Makun, Oluwakemi; Darbari, Deepika S; Chumpitazi, Corrie E; Airewele, Gladstone E; Ellison, Angela M; Smith-Whitley, Kim; Mahajan, Prashant; Sarnaik, Sharada A; Charles Casper, T; Cook, Larry J; Leonard, Julie; Hulbert, Monica L; Powell, Elizabeth C; Liem, Robert I; Hickey, Robert; Krishnamurti, Lakshmanan; Hillery, Cheryl A; Brousseau, David C

2017-06-12

Detecting change in health status over time and ascertaining meaningful changes are critical elements when using health-related quality of life (HRQL) instruments to measure patient-centered outcomes. The PedsQL™ Sickle Cell Disease module, a disease specific HRQL instrument, has previously been shown to be valid and reliable. Our objectives were to determine the longitudinal validity of the PedsQL™ Sickle Cell Disease module and the change in HRQL that is meaningful to patients. An ancillary study was conducted utilizing a multi-center prospective trial design. Children ages 4-21 years with sickle cell disease admitted to the hospital for an acute painful vaso-oclusive crisis were eligible. Children completed HRQL assessments at three time points (in the Emergency Department, one week post-discharge, and at return to baseline (One to three months post-discharge). The primary outcome was change in HRQL score. Both distribution (effect size, standard error of measurement (SEM)) and anchor (global change assessment) based methods were used to determine the longitudinal validity and meaningful change in HRQL. Changes in HRQL meaningful to patients were identified by anchoring the change scores to the patient's perception of global improvement in pain. Moderate effect sizes (0.20-0.80) were determined for all domains except the Communication I and Cognitive Fatigue domains. The value of 1 SEM varied from 3.8-14.6 across all domains. Over 50% of patients improved by at least 1 SEM in Total HRQL score. A HRQL change score of 7-10 in the pain domains represented minimal perceived improvement in HRQL and a HRQL change score of 18 or greater represented moderate to large improvement. The PedsQL™ Sickle Cell Disease Module is responsive to changes in HRQL in patients experiencing acute painful vaso-occlusive crises. The study data establish longitudinal validity and meaningful change parameters for the PedsQL™ Sickle Cell Disease Module. ClinicalTrials.gov (study identifier: NCT01197417 ). Date of registration: 08/30/2010.

Perception of labour pain among the Yoruba ethnic group in Nigeria.

PubMed

Kuti, O; Faponle, A F

2006-05-01

In Nigeria, it is generally assumed that labour is well tolerated and pain relief is not usually considered an important part of intra-partum care. This prospective study was carried out to assess mothers' perception of labour pain and determine any factor that may influence it. During the period of study, 281 women who delivered at Wesley Guild Hospital Ilesa, Nigeria were interviewed within 2 h of delivery to assess the severity of labour pain and desire for analgesia. Perception of labour pain was assessed using a 3-point verbal rating. The majority (68.3%) of women described labour pain as severe with only 5.3% describing it as mild. More than 86% of the women would want the pain relieved. Perception of pain was not influenced by age, parity and educational level. Management of pain in labour should form an important part of intra-partum care as is the case in developed countries.

[Psychosocial stressors and pain sensitivity in chronic pain disorder with somatic and psychological factors (F45.41)].

PubMed

Studer, M; Stewart, J; Egloff, N; Zürcher, E; von Känel, R; Brodbeck, J; Grosse Holtforth, M

2017-02-01

Increased pain sensitivity is characteristic for patients with chronic pain disorder with somatic and psychological factors (F45.41). Persistent stress can induce, sustain, and intensify pain sensitivity, thereby modulating pain perception. In this context, it would be favorable to investigate which psychosocial stressors are empirically linked to pain sensitivity. The aim of this study was to examine the relationship between psychosocial stressors and pain sensitivity in a naturalistic sample of patients with chronic pain disorder with somatic and psychological factors (F45.41). We assessed 166 patients with chronic pain disorder with somatic and psychological factors (F45.41) at entry into an inpatient pain clinic. Pain sensitivity was measured with a pain provocation test (Algopeg) at the middle finger and earlobe. Stressors assessed were exposure to war experiences, adverse childhood experiences, illness-related inability to work, relationship problems, and potentially life-threatening accidents. Correlation analyses and structural equation modeling were used to examine which stressors showed the strongest prediction of pain sensitivity. Patients exhibited generally heightened pain sensitivity. Both exposure to war and illness-related inability to work showed significant bivariate correlations with pain sensitivity. In addition to age, they also predicted a further increase in pain sensitivity in the structural equation model. Bearing in mind the limitations of this cross-sectional study, these findings may contribute to a better understanding of the link between psychosocial stressors and pain sensitivity.

The language of pain: A short study

PubMed Central

Rathnam, Arun; Madan, Nidhi; Madan, Neeti

2010-01-01

Background: Pain perception is a very controversial topic in child patients. It is affected by various factors such as fear, anxiety, previous experiences, parental factors, and pain threshold. The communication of such pain by the child to the parent is also very confusing with children having rudimentary and developing communication skills. A study to evaluate the pain perception of children and the parental understanding of the children's pain would be helpful in this scenario. The effect on behavior due to pain is also attempted in this particular study. Materials and Methods: A cross-sectional study of 100 children aged between 5-13 years accompanied by either parent was performed. Data collection was done with the help of questionnaires, which assessed the parental understanding of the child's pain. Pain perception recording was done with the Visual Analog Scale of Faces (VASOF). The behavior of the child was noted using the Frankl's behavior rating scale. Data was collated and statistical analysis was performed using the SPSS (version 10) software. Results and conclusion: The results show that parental factors such as education, work culture, influence parental understanding of pain. VASOF proves to be a reliable tool for pain perception in children. Behavior of the child shows a positive correlation to pain perception. PMID:22114404

Racial bias in pain perception and response: experimental examination of automatic and deliberate processes

PubMed Central

Mathur, Vani A.; Richeson, Jennifer A.; Paice, Judith A.; Muzyka, Michael; Chiao, Joan Y.

2014-01-01

Racial disparities in pain treatment pose a significant public health and scientific problem. Prior studies demonstrate clinicians and non-clinicians are less perceptive, and suggest less treatment for, the pain of African Americans, relative to European Americans. Here we investigate the effects of explicit/implicit patient race presentation, patient race, and perceiver race on pain perception and response. African American and European American participants rated pain perception, empathy, helping motivation, and treatment suggestion in response to vignettes about patients’ pain. Vignettes were accompanied by a rapid (implicit), or static (explicit) presentation of an African or European American patient’s face. Participants perceived and responded more to European American patients in the implicit prime condition, when the effect of patient race was below the level of conscious regulation. This effect was reversed when patient race was presented explicitly. Additionally, female participants perceived and responded more to the pain of all patients, relative to male participants, and in the implicit prime condition, African American participants were more perceptive and responsive than European Americans to the pain of all patients. Taken together, these results suggest that known disparities in pain treatment may be largely due to automatic (below the level of conscious regulation), rather than deliberate (subject to conscious regulation) biases. These biases were not associated with traditional implicit measures of racial attitudes, suggesting that biases in pain perception and response may be independent of general prejudice. Perspective Results suggest racial biases in pain perception and treatment are at least partially due to automatic processes. When the relevance of patient race is made explicit, however, biases are attenuated and even reversed. We also find preliminary evidence that African Americans may be more sensitive to the pain of others than European Americans. PMID:24462976

Do ethnicity and gender have an impact on pain thresholds in minor dermatologic procedures? A study on thermal pain perception thresholds in Asian ethinic groups.

PubMed

Yosipovitch, Gil; Meredith, Gregory; Chan, Yiong Huak; Goh, Chee Leok

2004-02-01

The perception of pain is a personal experience influenced by many factors, including genetic, ethnic and cultural issues. Understanding these perceptions is especially important in dermatologic patients undergoing minor surgical operations and who often differ in their pain response to surgical treatments. Little is known about how these differences affect the perception of experimental pain. The purpose of this study was to determine experimental pain perception differences in three distinct East Asian ethnic populations. Pain thresholds were examined with a psychophysical computerized quantitative thermal sensory testing device (TSA 2001) in healthy volunteers recruited from three different Asian ethnic groups. Using the methods of limits, experimental pain perception threshold was measured on the forehead and volar aspect of the forearm in 49 healthy subjects. The measurements were then repeated after skin barrier perturbation with adhesive tape stripping of the stratum corneum. All three ethnic groups were analyzed separately with respect to age, gender educational level and skin type. A total of 20 Chinese, 14 Malay and 15 Indian subjects completed the study. Thermal pain thresholds were similar in all three ethnic groups before and after tape strippings. No significant differences were noted between genders. Using quantitative sensory thermal testing, we demonstrated that no significant differences in pain occur between different races and genders.

Tonic blood pressure modulates the relationship between baroreceptor cardiac reflex sensitivity and cognitive performance.

PubMed

Del Paso, Gustavo A Reyes; González, M Isabel; Hernández, José Antonio; Duschek, Stefan; Gutiérrez, Nicolás

2009-09-01

This study explored the effects of tonic blood pressure on the association between baroreceptor cardiac reflex sensitivity and cognitive performance. Sixty female participants completed a mental arithmetic task. Baroreceptor reflex sensitivity was assessed using sequence analysis. An interaction was found, indicating that the relationship between baroreceptor reflex sensitivity and cognitive performance is modulated by blood pressure levels. Reflex sensitivity was inversely associated to performance indices in the subgroup of participants with systolic blood pressure above the mean, whereas the association was positive in participants with systolic values below the mean. These results are in accordance with the findings in the field of pain perception and suggest that tonic blood pressure modulates the inhibitory effects of baroreceptor stimulation on high central nervous functions.

The Efficacy of a Perceptive Rehabilitation on Postural Control in Patients with Chronic Nonspecific Low Back Pain

ERIC Educational Resources Information Center

Paolucci, Teresa; Fusco, Augusto; Iosa, Marco; Grasso, Maria R.; Spadini, Ennio; Paolucci, Stefano; Saraceni, Vincenzo M.; Morone, Giovanni

2012-01-01

Patients with chronic low back pain have a worse posture, probably related to poor control of the back muscles and altered perception of the trunk midline. The aim of this study was to evaluate the efficacy of a perceptive rehabilitation in terms of stability and pain relief in patients with chronic nonspecific low back pain. Thirty patients were…

Conditioned Pain Modulation and Situational Pain Catastrophizing as Preoperative Predictors of Pain following Chest Wall Surgery: A Prospective Observational Cohort Study

PubMed Central

Grosen, Kasper; Vase, Lene; Pilegaard, Hans K.; Pfeiffer-Jensen, Mogens; Drewes, Asbjørn M.

2014-01-01

Background Variability in patients' postoperative pain experience and response to treatment challenges effective pain management. Variability in pain reflects individual differences in inhibitory pain modulation and psychological sensitivity, which in turn may be clinically relevant for the disposition to acquire pain. The aim of this study was to investigate the effects of conditioned pain modulation and situational pain catastrophizing on postoperative pain and pain persistency. Methods Preoperatively, 42 healthy males undergoing funnel chest surgery completed the Spielberger's State-Trait Anxiety Inventory and Beck's Depression Inventory before undergoing a sequential conditioned pain modulation paradigm. Subsequently, the Pain Catastrophizing Scale was introduced and patients were instructed to reference the conditioning pain while answering. Ratings of movement-evoked pain and consumption of morphine equivalents were obtained during postoperative days 2–5. Pain was reevaluated at six months postoperatively. Results Patients reporting persistent pain at six months follow-up (n = 15) were not significantly different from pain-free patients (n = 16) concerning preoperative conditioned pain modulation response (Z = 1.0, P = 0.3) or level of catastrophizing (Z = 0.4, P = 1.0). In the acute postoperative phase, situational pain catastrophizing predicted movement-evoked pain, independently of anxiety and depression (β = 1.0, P = 0.007) whereas conditioned pain modulation predicted morphine consumption (β = −0.005, P = 0.001). Conclusions Preoperative conditioned pain modulation and situational pain catastrophizing were not associated with the development of persistent postoperative pain following funnel chest repair. Secondary outcome analyses indicated that conditioned pain modulation predicted morphine consumption and situational pain catastrophizing predicted movement-evoked pain intensity in the acute postoperative phase. These findings may have important implications for developing strategies to treat or prevent acute postoperative pain in selected patients. Pain may be predicted and the malfunctioning pain inhibition mechanism as tested with CPM may be treated with suitable drugs augmenting descending inhibition. PMID:24587268

Transcranial Direct Current Stimulation Targeting Primary Motor Versus Dorsolateral Prefrontal Cortices: Proof-of-Concept Study Investigating Functional Connectivity of Thalamocortical Networks Specific to Sensory-Affective Information Processing.

PubMed

Sankarasubramanian, Vishwanath; Cunningham, David A; Potter-Baker, Kelsey A; Beall, Erik B; Roelle, Sarah M; Varnerin, Nicole M; Machado, Andre G; Jones, Stephen E; Lowe, Mark J; Plow, Ela B

2017-04-01

The pain matrix is comprised of an extensive network of brain structures involved in sensory and/or affective information processing. The thalamus is a key structure constituting the pain matrix. The thalamus serves as a relay center receiving information from multiple ascending pathways and relating information to and from multiple cortical areas. However, it is unknown how thalamocortical networks specific to sensory-affective information processing are functionally integrated. Here, in a proof-of-concept study in healthy humans, we aimed to understand this connectivity using transcranial direct current stimulation (tDCS) targeting primary motor (M1) or dorsolateral prefrontal cortices (DLPFC). We compared changes in functional connectivity (FC) with DLPFC tDCS to changes in FC with M1 tDCS. FC changes were also compared to further investigate its relation with individual's baseline experience of pain. We hypothesized that resting-state FC would change based on tDCS location and would represent known thalamocortical networks. Ten right-handed individuals received a single application of anodal tDCS (1 mA, 20 min) to right M1 and DLPFC in a single-blind, sham-controlled crossover study. FC changes were studied between ventroposterolateral (VPL), the sensory nucleus of thalamus, and cortical areas involved in sensory information processing and between medial dorsal (MD), the affective nucleus, and cortical areas involved in affective information processing. Individual's perception of pain at baseline was assessed using cutaneous heat pain stimuli. We found that anodal M1 tDCS and anodal DLPFC tDCS both increased FC between VPL and sensorimotor cortices, although FC effects were greater with M1 tDCS. Similarly, anodal M1 tDCS and anodal DLPFC tDCS both increased FC between MD and motor cortices, but only DLPFC tDCS modulated FC between MD and affective cortices, like DLPFC. Our findings suggest that M1 stimulation primarily modulates FC of sensory networks, whereas DLPFC stimulation modulates FC of both sensory and affective networks. Our findings when replicated in a larger group of individuals could provide useful evidence that may inform future studies on pain to differentiate between effects of M1 and DLPFC stimulation. Notably, our finding that individuals with high baseline pain thresholds experience greater FC changes with DLPFC tDCS implies the role of DLPFC in pain modulation, particularly pain tolerance.

Transcranial Direct Current Stimulation Targeting Primary Motor Versus Dorsolateral Prefrontal Cortices: Proof-of-Concept Study Investigating Functional Connectivity of Thalamocortical Networks Specific to Sensory-Affective Information Processing

PubMed Central

Sankarasubramanian, Vishwanath; Cunningham, David A.; Potter-Baker, Kelsey A.; Beall, Erik B.; Roelle, Sarah M.; Varnerin, Nicole M.; Machado, Andre G.; Jones, Stephen E.; Lowe, Mark J.

2017-01-01

Abstract The pain matrix is comprised of an extensive network of brain structures involved in sensory and/or affective information processing. The thalamus is a key structure constituting the pain matrix. The thalamus serves as a relay center receiving information from multiple ascending pathways and relating information to and from multiple cortical areas. However, it is unknown how thalamocortical networks specific to sensory-affective information processing are functionally integrated. Here, in a proof-of-concept study in healthy humans, we aimed to understand this connectivity using transcranial direct current stimulation (tDCS) targeting primary motor (M1) or dorsolateral prefrontal cortices (DLPFC). We compared changes in functional connectivity (FC) with DLPFC tDCS to changes in FC with M1 tDCS. FC changes were also compared to further investigate its relation with individual's baseline experience of pain. We hypothesized that resting-state FC would change based on tDCS location and would represent known thalamocortical networks. Ten right-handed individuals received a single application of anodal tDCS (1 mA, 20 min) to right M1 and DLPFC in a single-blind, sham-controlled crossover study. FC changes were studied between ventroposterolateral (VPL), the sensory nucleus of thalamus, and cortical areas involved in sensory information processing and between medial dorsal (MD), the affective nucleus, and cortical areas involved in affective information processing. Individual's perception of pain at baseline was assessed using cutaneous heat pain stimuli. We found that anodal M1 tDCS and anodal DLPFC tDCS both increased FC between VPL and sensorimotor cortices, although FC effects were greater with M1 tDCS. Similarly, anodal M1 tDCS and anodal DLPFC tDCS both increased FC between MD and motor cortices, but only DLPFC tDCS modulated FC between MD and affective cortices, like DLPFC. Our findings suggest that M1 stimulation primarily modulates FC of sensory networks, whereas DLPFC stimulation modulates FC of both sensory and affective networks. Our findings when replicated in a larger group of individuals could provide useful evidence that may inform future studies on pain to differentiate between effects of M1 and DLPFC stimulation. Notably, our finding that individuals with high baseline pain thresholds experience greater FC changes with DLPFC tDCS implies the role of DLPFC in pain modulation, particularly pain tolerance. PMID:28142257

Pain-related psychological issues in hand therapy.

PubMed

Hamasaki, Tokiko; Pelletier, René; Bourbonnais, Daniel; Harris, Patrick; Choinière, Manon

Literature review. Pain is a subjective experience that results from the modulation of nociception conveyed to the brain via the nervous system. Perception of pain takes place when potential or actual noxious stimuli are appraised as threats of injury. This appraisal is influenced by one's cognitions and emotions based on her/his pain-related experiences, which are processed in the forebrain and limbic areas of the brain. Unarguably, patients' psychological factors such as cognitions (eg, pain catastrophizing), emotions (eg, depression), and pain-related behaviors (eg, avoidance) can influence perceived pain intensity, disability, and treatment outcomes. Therefore, hand therapists should address the patient pain experience using a biopsychosocial approach. However, in hand therapy, a biomedical perspective predominates in pain management by focusing solely on tissue healing. This review aims to raise awareness among hand therapists of the impact of pain-related psychological factors. This literature review allowed to describe (1) how the neurophysiological mechanisms of pain can be influenced by various psychological factors, (2) several evidence-based interventions that can be integrated into hand therapy to address these psychological issues, and (3) some approaches of psychotherapy for patients with maladaptive pain experiences. Restoration of sensory and motor functions as well as alleviating pain is at the core of hand therapy. Numerous psychological factors including patients' beliefs, cognitions, and emotions alter their pain experience and may impact on their outcomes. Decoding the biopsychosocial components of the patients' pain is thus essential for hand therapists. Copyright © 2018 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Neurophysiology of the cortical pain network: revisiting the role of S1 in subjective pain perception via standardized low-resolution brain electromagnetic tomography (sLORETA).

PubMed

Nir, Rony-Reuven; Lev, Rina; Moont, Ruth; Granovsky, Yelena; Sprecher, Elliot; Yarnitsky, David

2008-11-01

Multiple studies have supported the usefulness of standardized low-resolution brain electromagnetic tomography (sLORETA) in localizing generators of scalp-recorded potentials. The current study implemented sLORETA on pain event-related potentials, primarily aiming at validating this technique for pain research by identifying well-known pain-related regions. Subsequently, we pointed at investigating the still-debated and ambiguous topic of pain intensity coding at these regions, focusing on their relative impact on subjective pain perception. sLORETA revealed significant activations of the bilateral primary somatosensory (SI) and anterior cingulate cortices and of the contralateral operculoinsular and dorsolateral prefrontal (DLPFC) cortices (P < .05 for each). Activity of these regions, excluding DLPFC, correlated with subjective numerical pain scores (P < .05 for each). However, a multivariate regression analysis (R = .80; P = .024) distinguished the contralateral SI as the only region whose activation magnitude significantly predicted the subjective perception of noxious stimuli (P = .020), further substantiated by a reduced regression model (R = .75, P = .008). Based on (1) correspondence of the pain-activated regions identified by sLORETA with the acknowledged imaging-based pain-network and (2) the contralateral SI proving to be the most contributing region in pain intensity coding, we found sLORETA to be an appropriate tool for relevant pain research and further substantiated the role of SI in pain perception. Because the literature of pain intensity coding offers inconsistent findings, the current article used a novel tool for revisiting this controversial issue. Results suggest that it is the activation magnitude of SI, which solely establishes the significant correlation with subjective pain ratings, in accordance with the classical clinical thinking, relating SI lesions to diminished perception of pain. Although this study cannot support a causal relation between SI activation magnitude and pain perception, such relation might be insinuated.

The Relationship between Strategies of Coping and Perception of Pain in Three Chronic Pain Groups.

ERIC Educational Resources Information Center

Anderson, Louis P.; Rehm, Lynn P.

1984-01-01

Examined the relationship between perception of pain, personality, coping, and the reaction of family members in three chronic pain groups (sickle cell anemia, arthritis, and low back pain) (N=60). Analyses suggested that the three groups were not distinguishable in coping, personality, or in their experience of pain. (LLL)

Racial bias in pain perception and response: experimental examination of automatic and deliberate processes.

PubMed

Mathur, Vani A; Richeson, Jennifer A; Paice, Judith A; Muzyka, Michael; Chiao, Joan Y

2014-05-01

Racial disparities in pain treatment pose a significant public health and scientific problem. Prior studies have demonstrated that clinicians and nonclinicians are less perceptive of, and suggest less treatment for, the pain of African Americans relative to European Americans. Here we investigate the effects of explicit/implicit patient race presentation, patient race, and perceiver race on pain perception and response. African American and European American participants rated pain perception, empathy, helping motivation, and treatment suggestion in response to vignettes about patients' pain. Vignettes were accompanied by a rapid (implicit) or static (explicit) presentation of an African or European American patient's face. Participants perceived and responded more to European American patients in the implicit prime condition, when the effect of patient race was below the level of conscious regulation. This effect was reversed when patient race was presented explicitly. Additionally, female participants perceived and responded more to the pain of all patients, relative to male participants, and in the implicit prime condition, African American participants were more perceptive and responsive than European Americans to the pain of all patients. Taken together, these results suggest that known disparities in pain treatment may be largely due to automatic (below the level of conscious regulation) rather than deliberate (subject to conscious regulation) biases. These biases were not associated with traditional implicit measures of racial attitudes, suggesting that biases in pain perception and response may be independent of general prejudice. Results suggest that racial biases in pain perception and treatment are at least partially due to automatic processes. When the relevance of patient race is made explicit, however, biases are attenuated and even reversed. We also find preliminary evidence that African Americans may be more sensitive to the pain of others than are European Americans. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

Anxiety and stress can predict pain perception following a cognitive stress.

PubMed

Hoeger Bement, Marie; Weyer, Andy; Keller, Manda; Harkins, April L; Hunter, Sandra K

2010-08-04

Hoeger Bement, M.K., A. Weyer, M. Keller, A. Harkins, and S.K. Hunter. Anxiety and stress can predict pain perception following a cognitive stressor. PHYSIOL BEHAV 000-000. The purpose of this study was to investigate the influence of a cognitive stressor on pain perception and determine individual characteristics that may predict the pain response. Twenty-five subjects participated in three sessions: one familiarization and two experimental. The experimental sessions involved measurement of pain perception before and after 1) mental math tasks (stressor session) and 2) quiet rest (control session). Pain threshold and ratings were assessed with a mechanical noxious stimulus. Changes in stress and anxiety were examined with self-reported and physiological measures including questionnaires, visual analogue scales, and salivary cortisol levels. During the control session, stress and anxiety decreased and pain reports remain unchanged. During the stressor session, stress and anxiety increased and pain reports were variable among subjects. Based on the pain response to mental math, subjects were divided into three groups (increase, decrease or no change in pain). The increase-pain group (n=8) had lower baseline stress and anxiety, lower baseline pain reports, and large anxiety response following the mental math. In contrast, the decrease-pain group (n=9) had higher baseline stress and anxiety levels, higher baseline pain reports, and a large increase in cortisol levels. Thus, the differential response in the changes in pain perception was related to anxiety and stress levels prior to and during the cognitive stressor, indicating that psychosocial characteristics can help determine the stress-induced pain response. Copyright 2010 Elsevier Inc. All rights reserved.

Beliefs about expectations moderate the influence of expectations on pain perception.

PubMed

Handley, Ian M; Fowler, Stephanie L; Rasinski, Heather M; Helfer, Suzanne G; Geers, Andrew L

2013-03-01

Expectations congruently influence, or bias, pain perception. Recent social psychological research reveals that individuals differ in the extent to which they believe in expectation biases and that individuals who believe in expectation biases may adjust for this bias in their perceptions and reactions. That is, idiosyncratic beliefs about expectations can moderate the influence of expectations on experience. Prior research has not examined whether idiosyncratic beliefs about expectations can alter the degree to which one's expectations influence pain perception. Using a laboratory pain stimulus, we examined the possibility that beliefs about expectation biases alter pain responses following both pain- and placebo-analgesic expectations. Participants' beliefs about expectation biases were measured. Next, participants were randomly assigned to receive either a pain expectation or a placebo-analgesia expectation prior to a cold-pressor task. After the task, participants rated their pain. Beliefs about expectation biases significantly influenced pain reports. Specifically, pain reports were more influenced by provided expectations the less participants believed in expectation biases (i.e., pain expectations resulted in more pain than analgesia expectations). Beliefs about the expectation bias are an important and under-examined predictor of pain and placebo analgesia.

Improving student dentist competencies and perception of difficulty in delivering care to children with developmental disabilities using a virtual patient module.

PubMed

Kleinert, Harold L; Sanders, Carla; Mink, John; Nash, David; Johnson, Jeff; Boyd, Sara; Challman, Sandra

2007-02-01

An interactive, multimedia, virtual patient module was designed and developed on compact disc (CD-ROM) to address the need for student dentists to increase their competence and decrease their perception of difficulty in caring for children with developmental disabilities. A development team consisting of pediatric dentistry faculty members, parents of children with developmental disabilities, an individual with a developmental disability, and educational specialists developed an interactive virtual patient case. The case involved a ten-year-old child with Down syndrome presenting with a painful tooth. Student dentists were required to make decisions regarding proper interactions with the child, as well as appropriate clinical procedures throughout the case. Differences in perceived difficulty level and knowledge change were measured, as well as the student dentists' overall satisfaction with the learning experience. Significant results were obtained in both perceived difficulty level and knowledge-based measures for student dentists. Participants reported overall satisfaction with the modules. Preparing student dentists to provide sensitive and competent care for children with developmental disabilities is a critical need within dentistry. This study demonstrated that an interactive, multimedia (CD-ROM), virtual patient learning module for student dentists is potentially an effective tool in meeting this need.

Measurement of acute nonspecific low back pain perception in primary care physical therapy: reliability and validity of the brief illness perception questionnaire.

PubMed

Hallegraeff, Joannes M; van der Schans, Cees P; Krijnen, Wim P; de Greef, Mathieu H G

2013-02-01

The eight-item Brief Illness Perception Questionnaire is used as a screening instrument in physical therapy to assess mental defeat in patients with acute low back pain, besides patient perception might determine the course and risk for chronic low back pain. However, the psychometric properties of the Brief Illness Perception Questionnaire in common musculoskeletal disorders like acute low back pain have not been adequately studied. Patients' perceptions vary across different populations and affect coping styles. Thus, our aim was to determine the internal consistency, test-retest reliability and validity of the Dutch language version of the Brief Illness Perception Questionnaire in acute non-specific low back pain patients in primary care physical therapy. A non-experimental cross-sectional study with two measurements was performed. Eighty-four acute low back pain patients, in multidisciplinary health care center in Dutch primary care with a sample mean (SD) age of 42 (12) years, participated in the study. Internal consistency (Cronbach's α) and test-retest procedures (Intraclass Correlation Coefficients and limits of agreement) were evaluated at a one-week interval. The concurrent validity of the Brief Illness Perception Questionnaire was examined by using the Mental Health Component of the Short Form 36 Health Survey. The Cronbach's α for internal consistency was 0.73 (95% CI, 0.67 - 0.83); and the Intraclass Correlation Coefficient test-retest reliability was acceptable: 0.72 (95% CI, 0.53 - 0.82), however, the limits of agreement were large. The Intraclass Correlation Coefficient measuring concurrent validity 0.65 (95% CI, 0.46 - 0.80). The Dutch version of the Brief Illness Perception Questionnaire is an appropriate instrument for measuring patients' perceptions in acute low back pain patients, showing acceptable internal consistency and reliability. Concurrent validity is adequate, however, the instrument may be unsuitable for detecting changes in low back pain perception over time.

[The Recognition of Emotions, Empathy and Moral Judgment in the National Mental Health Survey in Colombia, 2015].

PubMed

Matallana, Diana; Gómez-Restrepo, Carlos; Ramirez, Paulina; Martínez, Nathalie Tamayo; Rondon, Martin

2016-12-01

Social cognition refers to the mental processes involved in social interactions. Different aspects, such as the perception of others, self-knowledge, motivation and the cultural context, can modulate empathy responses and moral judgments regarding the actions of others. The National Mental Health Survey (ENSM for its acronym in Spanish) explored aspects of social cognition such as the perception of emotions, empathy and moral judgment in situations in which another person experiences pain. To describe the overall findings of the ENSM in relation to the emotional perception and empathic responses to situations where pain is inflicted on others in an intentional or accidental manner. A total of 3863 people aged 18-96 years old completed the social cognition module. They were asked to identify the emotions expressed in the images of several faces. A modified version of the awareness of social inference test (TASIT) was used. Additionally, the cognitive, affective, and moral elements of empathy were assessed with a modified version of the empathy for pain task (EPT), which uses a sequence of images in which someone is being hurt. Happiness was identified by 91.5% of those interviewed; neutral or emotionless faces were identified by 65%; 55% of respondents correctly identified surprise. Only 19.7%, 21.8% and 27.4% could identify negative emotions like fear, disgust and sadness, respectively. When the data were analysed by age, poverty status, and different regions of the country, the results tend to vary. As regards empathy, 73.7% correctly identified intentional actions, and accidental actions were identified by 56.6%. According to the moral judgment of some respondents, even in situations where the pain was caused by accident, there must be some kind of punishment (20.7% deserved a low punishment and 26.8% a moderate one). Noteworthy findings include the high recognition of happiness by the respondents, in contrast to the apparent difficulty in recognising sadness, and paradoxical results regarding punishment and empathy. This should be studied in greater detail, but these results can contribute to a deeper understanding of the complex Colombian social context. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Sex differences and hormonal modulation of deep tissue pain

PubMed Central

Traub, Richard J.; Ji, Yaping

2013-01-01

Women disproportionately suffer from many deep tissue pain conditions. Experimental studies show that women have lower pain thresholds, higher pain ratings and less tolerance to a range of painful stimuli. Most clinical and epidemiological reports suggest female gonadal hormones modulate pain for some, but not all, conditions. Similarly, animal studies support greater nociceptive sensitivity in females in many deep tissue pain models. Gonadal hormones modulate responses in primary afferents, dorsal horn neurons and supraspinal sites, but the direction of modulation is variable. This review will examine sex differences in deep tissue pain in humans and animals focusing on the role of gonadal hormones (mainly estradiol) as an underlying component of the modulation of pain sensitivity. PMID:23872333

The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership.

PubMed

Martini, Matteo; Kilteni, Konstantina; Maselli, Antonella; Sanchez-Vives, Maria V

2015-09-29

The feeling of "ownership" over an external dummy/virtual body (or body part) has been proven to have both physiological and behavioural consequences. For instance, the vision of an "embodied" dummy or virtual body can modulate pain perception. However, the impact of partial or total invisibility of the body on physiology and behaviour has been hardly explored since it presents obvious difficulties in the real world. In this study we explored how body transparency affects both body ownership and pain threshold. By means of virtual reality, we presented healthy participants with a virtual co-located body with four different levels of transparency, while participants were tested for pain threshold by increasing ramps of heat stimulation. We found that the strength of the body ownership illusion decreases when the body gets more transparent. Nevertheless, in the conditions where the body was semi-transparent, higher levels of ownership over a see-through body resulted in an increased pain sensitivity. Virtual body ownership can be used for the development of pain management interventions. However, we demonstrate that providing invisibility of the body does not increase pain threshold. Therefore, body transparency is not a good strategy to decrease pain in clinical contexts, yet this remains to be tested.

The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership

PubMed Central

Martini, Matteo; Kilteni, Konstantina; Maselli, Antonella; Sanchez-Vives, Maria V.

2015-01-01

The feeling of “ownership” over an external dummy/virtual body (or body part) has been proven to have both physiological and behavioural consequences. For instance, the vision of an “embodied” dummy or virtual body can modulate pain perception. However, the impact of partial or total invisibility of the body on physiology and behaviour has been hardly explored since it presents obvious difficulties in the real world. In this study we explored how body transparency affects both body ownership and pain threshold. By means of virtual reality, we presented healthy participants with a virtual co-located body with four different levels of transparency, while participants were tested for pain threshold by increasing ramps of heat stimulation. We found that the strength of the body ownership illusion decreases when the body gets more transparent. Nevertheless, in the conditions where the body was semi-transparent, higher levels of ownership over a see-through body resulted in an increased pain sensitivity. Virtual body ownership can be used for the development of pain management interventions. However, we demonstrate that providing invisibility of the body does not increase pain threshold. Therefore, body transparency is not a good strategy to decrease pain in clinical contexts, yet this remains to be tested. PMID:26415748

Predictors and perception of pain in women undergoing first trimester surgical abortion.

PubMed

Singh, Rameet H; Ghanem, Khalil G; Burke, Anne E; Nichols, Mark D; Rogers, Kathy; Blumenthal, Paul D

2008-08-01

The aim of the study was to evaluate pain and predictors of pain in women undergoing electric (EVA) or manual vacuum aspiration (MVA) for first trimester surgical abortions and to examine how perceptions of pain differ among participants, advocates (participant support person) and physicians. In this randomized controlled study, women presenting for first trimester abortion underwent standardized EVA or MVA. Participants completed questionnaires, visual analog scales (VAS) and Likert scales for pain. Logistic and linear regression models were used to analyze the data. Nonwhite women and women who preoperatively expected more pain reported higher procedure-related pain scores. Vacuum source, previous history of abortion, comfort with decision to have an abortion and partner involvement did not affect participant pain scores. In the multivariable analyses, no single factor predicted procedure-associated pain. The advocates perceived that more educated women had less pain. Physicians felt longer procedures and a woman's fear of pelvic examinations caused more pain. Physicians believed women had less pain than the participants reported themselves (p<.001). Only physicians thought that EVA was less painful than MVA (p<.01). Distinct factors other than vacuum source affect the perception of abortion-related pain. Understanding these factors may help inform counseling strategies aimed at ameliorating pain perception during first trimester abortions.

How Does Anodal Transcranial Direct Current Stimulation of the Pain Neuromatrix Affect Brain Excitability and Pain Perception? A Randomised, Double-Blind, Sham-Control Study

PubMed Central

Vaseghi, Bita; Zoghi, Maryam; Jaberzadeh, Shapour

2015-01-01

Background Integration of information between multiple cortical regions of the pain neuromatrix is thought to underpin pain modulation. Although altered processing in the primary motor (M1) and sensory (S1) cortices is implicated in separate studies, the simultaneous changes in and the relationship between these regions are unknown yet. The primary aim was to assess the effects of anodal transcranial direct current stimulation (a-tDCS) over superficial regions of the pain neuromatrix on M1 and S1 excitability. The secondary aim was to investigate how M1 and S1 excitability changes affect sensory (STh) and pain thresholds (PTh). Methods Twelve healthy participants received 20 min a-tDCS under five different conditions including a-tDCS of M1, a-tDCS of S1, a-tDCS of DLPFC, sham a-tDCS, and no-tDCS. Excitability of dominant M1 and S1 were measured before, immediately, and 30 minutes after intervention respectively. Moreover, STh and PTh to peripheral electrical and mechanical stimulation were evaluated. All outcome measures were assessed at three time-points of measurement by a blind rater. Results A-tDCS of M1 and dorsolateral prefrontal cortex (DLPFC) significantly increased brain excitability in M1 (p < 0.05) for at least 30 min. Following application of a-tDCS over the S1, the amplitude of the N20-P25 component of SEPs increased immediately after the stimulation (p < 0.05), whilst M1 stimulation decreased it. Compared to baseline values, significant STh and PTh increase was observed after a-tDCS of all three stimulated areas. Except in M1 stimulation, there was significant PTh difference between a-tDCS and sham tDCS. Conclusion a-tDCS of M1 is the best spots to enhance brain excitability than a-tDCS of S1 and DLPFC. Surprisingly, a-tDCS of M1 and S1 has diverse effects on S1 and M1 excitability. A-tDCS of M1, S1, and DLPFC increased STh and PTh levels. Given the placebo effects of a-tDCS of M1 in pain perception, our results should be interpreted with caution, particularly with respect to the behavioural aspects of pain modulation. Trial Registration Australian New Zealand Clinical Trials, ACTRN12614000817640, http://www.anzctr.org.au/. PMID:25738603

Attenuation of pCREB and Egr1 expression in the insular and anterior cingulate cortices associated with enhancement of CFA-evoked mechanical hypersensitivity after repeated forced swim stress.

PubMed

Imbe, Hiroki; Kimura, Akihisa

2017-09-01

The perception and response to pain are severely impacted by exposure to stressors. In some animal models, stress increases pain sensitivity, which is termed stress-induced hyperalgesia (SIH). The insular cortex (IC) and anterior cingulate cortex (ACC), which are typically activated by noxious stimuli, affect pain perception through the descending pain modulatory system. In the present study, we examined the expression of phospho-cAMP response element-binding protein (pCREB) and early growth response 1 (Egr1) in the IC and ACC at 3h (the acute phase of peripheral tissue inflammation) after complete Freund's adjuvant (CFA) injection in naïve rats and rats preconditioned with forced swim stress (FS) to clarify the effect of FS, a stressor, on cortical cell activities in the rats showing SIH induced by FS. The CFA injection into the hindpaw induced mechanical hypersensitivity and increased the expression of the pCREB and Egr1 in the IC and ACC at 3h after the injection. FS (day 1, 10min; days 2-3, 20min) prior to the CFA injection enhanced the CFA-induced mechanical hypersensitivity and attenuated the increase in the expression of pCREB and Egr1 in the IC and ACC. These findings suggested that FS modulates the CFA injection-induced neuroplasticity in the IC and ACC to enhance the mechanical hypersensitivity. These findings are thought to signify stressor-induced dysfunction of the descending pain modulatory system. Copyright © 2017 Elsevier Inc. All rights reserved.

Structural Health Monitoring: Leveraging Pain in the Human Body

NASA Astrophysics Data System (ADS)

Nayak, Subhadarshi

2012-07-01

Tissue damage, or the perception thereof, is managed through pain experience. The neurobiological process of pain triggers most effective defense mechanisms for our safety. Structural health monitoring (SHM) is also a very similar function, albeit in engineering systems. SHM technology can leverage many aspects of pain mechanisms to progress in several critical areas. Discrimination between features from the undamaged and damaged structures can follow the threshold gate mechanism of the pain perception. Furthermore, the sensing mechanisms can be adaptive to changes by adjusting the threshold as does the pain perception. A distributed sensor network, often advanced by SHM, can be made fault-tolerant and robust by following the perception way of self-organization and redundancy. Data handling in real life is a huge challenge for large-scale SHM. As sensory data of pain is first cleaned, the threshold is then processed through experiential information gathering and use.

Being Moved by the Self and Others: Influence of Empathy on Self-Motion Perception

PubMed Central

Lopez, Christophe; Falconer, Caroline J.; Mast, Fred W.

2013-01-01

Background The observation of conspecifics influences our bodily perceptions and actions: Contagious yawning, contagious itching, or empathy for pain, are all examples of mechanisms based on resonance between our own body and others. While there is evidence for the involvement of the mirror neuron system in the processing of motor, auditory and tactile information, it has not yet been associated with the perception of self-motion. Methodology/Principal Findings We investigated whether viewing our own body, the body of another, and an object in motion influences self-motion perception. We found a visual-vestibular congruency effect for self-motion perception when observing self and object motion, and a reduction in this effect when observing someone else's body motion. The congruency effect was correlated with empathy scores, revealing the importance of empathy in mirroring mechanisms. Conclusions/Significance The data show that vestibular perception is modulated by agent-specific mirroring mechanisms. The observation of conspecifics in motion is an essential component of social life, and self-motion perception is crucial for the distinction between the self and the other. Finally, our results hint at the presence of a “vestibular mirror neuron system”. PMID:23326302

Gender-related differences in irritable bowel syndrome: Potential mechanisms of sex hormones

PubMed Central

Meleine, Mathieu; Matricon, Julien

2014-01-01

According to epidemiological studies, twice as many women as men are affected by irritable bowel syndrome (IBS) in western countries, suggesting a role for sex hormones in IBS pathophysiology. Despite growing evidence about the implications of sex hormones in IBS symptom modulation, data on mechanisms by which they influence disease development are sparse. This review aims to determine the state of knowledge about the role of sex hormones in sensorimotor dysfunctions and to address the possible interplay of sex hormones with common risk factors associated with IBS. The scientific bibliography was searched using the following keywords: irritable bowel syndrome, sex, gender, ovarian hormone, estradiol, progesterone, testosterone, symptoms, pain, sensitivity, motility, permeability, stress, immune system, brain activity, spinal, supraspinal, imaging. Ovarian hormones variations along the menstrual cycle affect sensorimotor gastrointestinal function in both healthy and IBS populations. They can modulate pain processing by interacting with neuromodulator systems and the emotional system responsible for visceral pain perception. These hormones can also modulate the susceptibility to stress, which is a pivotal factor in IBS occurrence and symptom severity. For instance, estrogen-dependent hyper-responsiveness to stress can promote immune activation or impairments of gut barrier function. In conclusion, whereas it is important to keep in mind that ovarian hormones cannot be considered as a causal factor of IBS, they arguably modulate IBS onset and symptomatology. However, our understanding of the underlying mechanisms remains limited and studies assessing the link between IBS symptoms and ovarian hormone levels are needed to improve our knowledge of the disease evolution with regard to gender. Further studies assessing the role of male hormones are also needed to understand fully the role of sex hormones in IBS. Finally, investigation of brain-gut interactions is critical to decipher how stress, ovarian hormones, and female brain processing of pain can translate into gut dysfunctions. PMID:24944465

Gender-related differences in irritable bowel syndrome: potential mechanisms of sex hormones.

PubMed

Meleine, Mathieu; Matricon, Julien

2014-06-14

According to epidemiological studies, twice as many women as men are affected by irritable bowel syndrome (IBS) in western countries, suggesting a role for sex hormones in IBS pathophysiology. Despite growing evidence about the implications of sex hormones in IBS symptom modulation, data on mechanisms by which they influence disease development are sparse. This review aims to determine the state of knowledge about the role of sex hormones in sensorimotor dysfunctions and to address the possible interplay of sex hormones with common risk factors associated with IBS. The scientific bibliography was searched using the following keywords: irritable bowel syndrome, sex, gender, ovarian hormone, estradiol, progesterone, testosterone, symptoms, pain, sensitivity, motility, permeability, stress, immune system, brain activity, spinal, supraspinal, imaging. Ovarian hormones variations along the menstrual cycle affect sensorimotor gastrointestinal function in both healthy and IBS populations. They can modulate pain processing by interacting with neuromodulator systems and the emotional system responsible for visceral pain perception. These hormones can also modulate the susceptibility to stress, which is a pivotal factor in IBS occurrence and symptom severity. For instance, estrogen-dependent hyper-responsiveness to stress can promote immune activation or impairments of gut barrier function. In conclusion, whereas it is important to keep in mind that ovarian hormones cannot be considered as a causal factor of IBS, they arguably modulate IBS onset and symptomatology. However, our understanding of the underlying mechanisms remains limited and studies assessing the link between IBS symptoms and ovarian hormone levels are needed to improve our knowledge of the disease evolution with regard to gender. Further studies assessing the role of male hormones are also needed to understand fully the role of sex hormones in IBS. Finally, investigation of brain-gut interactions is critical to decipher how stress, ovarian hormones, and female brain processing of pain can translate into gut dysfunctions.

[A gender perspective analysis of perception and practices in coronary disease in women from northern México].

PubMed

Juárez-Herrera Y Cairo, Lucero Aída; Castro-Vásquez, María Del Carmen; Ruiz-Cantero, María Teresa

2016-08-01

To analyze the perception of coronary risk and health care practices in a group of Mexican women, from a gendered perspective. Mixed methods: survey of 140 women; nine in-depth interviews to women with coronary disease; eight semi-structured interviews to physicians. proportions contrast for quantitative data; and procedures of grounded theory for qualitative information. More than 50% of women don't know their coronary risk and how to reduce it. Despite having information about heart disease, vulnerable women with chest pain sought medical attendance less than non-vulnerable women (p=0.0l); and are blamed by physicians. Women consider they lack sufficient information about how to reduce the risk of coronary disease, and blame themselves when ill. There are vulnerability conditions in women that modulate a low perception of their being at risk, and the scarcity of health care practices.

The analgesic effect of benzocaine mucoadhesive patches on orthodontic pain caused by elastomeric separators, a preliminary study.

PubMed

Eslamian, Ladan; Borzabadi-Farahani, Ali; Edini, Hosniye Zia; Badiee, Mohammad R; Lynch, Edward; Mortazavi, Alireza

2013-09-01

To study the effect of benzocaine mucoadhesive patches (20%) on orthodontic pain caused by elastomeric separators. A split-mouth design was used in 30 patients (12 female, 18 male, aged 23 ± 3.75 years). They were instructed to apply benzocaine and placebo patches randomly for right or left first permanent molars of maxillary/mandibular arches for 20 min and repeat this procedure every 6 h with a similar type patch. A 10 cm Visual Analogue Scale (VAS) was used for pain perception assessment in patients who were given benzocaine (benzocaine group) or placebo (placebo group) patches. Pain perception (VAS) was recorded immediately after separator placement and after 2, 6, 12, 18, 24, 48 and 72 h. The mean VAS (SD) for the placebo and benzocaine groups were 2.28 (1.08) and 1.63 (0.67), respectively. The pain peaked at 24 h. Significant pain perception differences were observed between groups at 2, 18, 24, 48 and 72 h. Pain perception was not different between genders or jaws investigated (p > 0.05). The Friedman test revealed significant differences in pain perception among various time intervals for benzocaine (χ (2) = 99.84, p = 0.000) and placebo (χ (2) = 102.361, p = 0.000) groups. Significant negative correlations (ρ) were found only between pain perception scores and patient's ages in the placebo group at 18 (-0.438), 24 (-0.526), 48 (-0.565) and 72 h (-0.458). The recorded mean VAS values were relatively low; however, the benzocaine 20% patches significantly reduced the post-separation orthodontic pain.

Knowledge, perception and practices of healthcare professionals at tertiary level hospitals in Kingston, Jamaica, regarding neonatal pain management.

PubMed

Young, J; Barton, M; Richards-Dawson, M A; Trotman, H

2008-01-01

To determine knowledge, perception and practices of healthcare professionals at tertiary level hospitals in Kingston, Jamaica, regarding neonatal pain management. Physicians and nurses actively involved in providing neonatal care at three tertiary level hospitals were invited to participate. A 21-item self-administered questionnaire was used to obtain information on knowledge, perception and practice of neonatal pain management. Descriptive analyses were performed. A total of 147 healthcare workers participated giving a response rate of 85%. Male to female ratio was 1: 4.4. Nurses accounted for 76 (52%) of the respondents while 70 (48%) were physicians. Seventy-three (50%) individuals were unaware of the degree of pain neonates were capable of experiencing and only 38 (27%) knew that premature infants were capable of feeling pain. One hundred and four (71%) respondents were able to identify physiological markers of pain and most respondents were able to discriminate between painful and non-painful procedures. However, 100 (68%) respondents rarely prescribed analgesia for procedures previously rated as painful. Seventy-one (51%) respondents admitted to not using analgesia for alleviating procedural pain in neonates. Twenty-five (18%) individuals thought that the procedure was too short to require analgesic support while 41 (30%) stated that medication was not usually prescribed for procedural pain. Physician scores were significantly higher than those attained by nurses for knowledge (p = 0.003) and for pain perception (p = 0.001) but no significant differences were noted for practice (p = 0.18). There is an overwhelming deficiency in the knowledge, perception and practice of neonatal pain management at tertiary level institutions in Kingston, Jamaica. There is the urgent need for the education of health professionals on neonatal pain management. This will in turn facilitate change in perception and eventually, along with the institution of local policies and protocols, influence practice.

Current pain education within undergraduate medical studies across Europe: Advancing the Provision of Pain Education and Learning (APPEAL) study.

PubMed

Briggs, Emma V; Battelli, Daniele; Gordon, David; Kopf, Andreas; Ribeiro, Sofia; Puig, Margarita M; Kress, Hans G

2015-08-10

Unrelieved pain is a substantial public health concern necessitating improvements in medical education. The Advancing the Provision of Pain Education and Learning (APPEAL) study aimed to determine current levels and methods of undergraduate pain medicine education in Europe. Using a cross-sectional design, publicly available curriculum information was sought from all medical schools in 15 representative European countries in 2012-2013. Descriptive analyses were performed on: the provision of pain teaching in dedicated pain modules, other modules or within the broader curriculum; whether pain teaching was compulsory or elective; the number of hours/credits spent teaching pain; pain topics; and teaching and assessment methods. Curriculum elements were publicly available from 242 of 249 identified schools (97%). In 55% (133/242) of schools, pain was taught only within compulsory non-pain-specific modules. The next most common approaches were for pain teaching to be provided wholly or in part via a dedicated pain module (74/242; 31%) or via a vertical or integrated approach to teaching through the broader curriculum, rather than within any specific module (17/242; 7%). The curricula of 17/242 schools (7%) showed no evidence of any pain teaching. Dedicated pain modules were most common in France (27/31 schools; 87%). Excluding France, only 22% (47/211 schools) provided a dedicated pain module and in only 9% (18/211) was this compulsory. Overall, the median number of hours spent teaching pain was 12.0 (range 4-56.0 h; IQR: 12.0) for compulsory dedicated pain modules and 9.0 (range 1.0-60.0 h; IQR: 10.5) for other compulsory (non-pain specific) modules. Pain medicine was principally taught in classrooms and assessed by conventional examinations. There was substantial international variation throughout. Documented pain teaching in many European medical schools falls far short of what might be expected given the prevalence and public health burden of pain. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

What Are the Predictors of Altered Central Pain Modulation in Chronic Musculoskeletal Pain Populations? A Systematic Review.

PubMed

Clark, Jacqui; Nijs, Jo; Yeowell, Gillian; Goodwin, Peter Charles

2017-09-01

Altered central pain modulation is the predominant pain mechanism in a proportion of chronic musculoskeletal pain disorders and is associated with poor outcomes. Although existing studies predict poor outcomes such as persistent pain and disability, to date there is little consensus on what factors specifically predict altered central pain modulation. To review the existing literature on the predictive factors specifically for altered central pain modulation in musculoskeletal pain populations. This is a systematic review in accordance with supplemented PRISMA guidelines. A systematic search was performed by 2 mutually blinded reviewers. Relevant articles were screened by title and abstract from Medline, Embase, PubMed, CINAHL, and Web of Science electronic databases. Alternative sources were also sought to locate missed potential articles. Eligibility included studies published in English, adults aged 18 to 65, musculoskeletal pain, baseline measurements taken at the pre-morbid or acute stage, > 3-month follow-up time after pain onset, and primary outcome measures specific to altered central pain modulation. Studies were excluded where there were concurrent diseases or they were non-predictive studies. Risk of bias was assessed using the quality in prognostic studies (QUIPS) tool. Study design, demographics, musculoskeletal region, inclusion/exclusion criteria, measurement timelines, predictor and primary outcome measures, and results were extracted. Data were synthesized qualitatively and strength of evidence was scored using the grading of recommendations, assessment, development, and evaluations (GRADE) scoring system. Nine eligible articles were located, in various musculoskeletal populations (whiplash, n = 2; widespread pain, n = 5; temporomandibular disorder, n = 2). Moderate evidence was found for 2 predictive factors of altered central pain modulation: 1) high sensory sensitivity (using genetic testing or quantitative sensory tests), and 2) psychological factors (somatization and poor self-expectation of recovery), at a pre-morbid or acute stage baseline. At the times of the article publications, the current definitions and clinical guidelines for identifying altered central pain modulation were not yet available. Careful interpretation of the information provided using current knowledge and published guidelines was necessary to extract information specific to altered central pain modulation in some of the studies, avoiding unwarranted assumptions. Premorbid and acute stage high sensory sensitivity and/or somatization are the strongest predictors of altered central pain modulation in chronic musculoskeletal pain to date. This is the first systematic review specifically targeting altered central pain modulation as the primary outcome in musculoskeletal pain populations. Early identification of people at risk of developing chronic pain with altered central pain modulation may guide clinicians in appropriate management, diminishing the burden of persistent pain on patients and heath care providers alike. Systematic Review Registration no.: PROSPERO 2015:CRD42015032394.Key words: Predictive factors, pre-morbid and acute stage baselines, altered central pain modulation, chronic musculoskeletal pain, sensory processing, somatization.

AMPK Phosphorylation Modulates Pain by Activation of NLRP3 Inflammasome

PubMed Central

Bullón, Pedro; Alcocer-Gómez, Elísabet; Carrión, Angel M.; Marín-Aguilar, Fabiola; Garrido-Maraver, Juan; Román-Malo, Lourdes; Ruiz-Cabello, Jesus; Culic, Ognjen; Ryffel, Bernhard; Apetoh, Lionel; Ghiringhelli, François; Battino, Maurizio; Sánchez-Alcazar, José Antonio

2016-01-01

Abstract Aims: Impairment in adenosine monophosphate-activated protein kinase (AMPK) activity and NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation are associated with several metabolic and inflammatory diseases. In this study, we investigated the role of AMPK/NLRP3 inflammasome axis in the molecular mechanism underlying pain perception. Results: Impairment in AMPK activation induced by compound C or sunitinib, two AMPK inhibitors, provoked hyperalgesia in mice (p<0.001) associated with marked NLRP3 inflammasome protein activation and increased serum levels of interleukin-1β (IL-1β) (24.56±0.82 pg/ml) and IL-18 (23.83±1.882 pg/ml) compared with vehicle groups (IL-1β: 8.15±0.44; IL-18: 4.92±0.4). This effect was rescued by increasing AMPK phosphorylation via metformin treatment (p<0.001), caloric restriction diet (p<0.001), or NLRP3 inflammasome genetic inactivation using NLRP3 knockout (nlrp3−/−) mice (p<0.001). Deficient AMPK activation and overactivation of NLRP3 inflammasome axis were also observed in blood cells from patients with fibromyalgia (FM), a prevalent human chronic pain disease. In addition, metformin treatment (200 mg/daily), which increased AMPK activation, restored all biochemical alterations examined by us in blood cells and significantly improved clinical symptoms, such as, pain, fatigue, depression, disturbed sleep, and tender points, in patients with FM. Innovation and Conclusions: These data suggest that AMPK/NLRP3 inflammasome axis participates in chronic pain and that NLRP3 inflammasome inhibition by AMPK modulation may be a novel therapeutic target to fight against chronic pain and inflammatory diseases as FM. Antioxid. Redox Signal. 24, 157–170. PMID:26132721

Sex-dependent effects of stress on brain correlates to empathy for pain.

PubMed

Gonzalez-Liencres, Cristina; Breidenstein, Anja; Wolf, Oliver T; Brüne, Martin

2016-07-01

Empathy is a fundamental attribute required for appropriate social functioning. The extent to which we empathize with others in pain is influenced by numerous factors. Being highly social species, humans face social stress on a regular basis, which undoubtedly affects how we react to our environment. It is not yet known how social stress may modulate our neural mechanisms when we empathize with others in painful circumstances, and its effects on empathic behavior are still unclear. For this reason, we recorded the electroencephalography (EEG) of healthy men and women, half of which were previously exposed to psychosocial stress, while they observed photographs of hands in painful and neutral situations. At the behavioral level, stress induced higher unpleasantness ratings to painful stimuli, and lower ratings to neutral pictures, independent of sex. At the neurophysiological level, we found that early (N110 over fronto-central sites) event-related potentials (ERPs) were not affected by stress, while late (P3 over centro-parietal regions) components showed a sex-dependent differential effect of stress. Correlation analyses further indicated a strong association between N110 with trait markers of empathy in all participants, while P3 was associated with the change in cortisol in stressed males. Our findings suggest that sex-dependent effects of social stress on the neural responses to empathy for pain give rise to comparable behaviors in men and women in the paradigm we employed, implying that each sex may engage in distinct mechanisms to cope with stress. Moreover, stress seems to modulate late neural mechanisms of empathy but not our early perception. Copyright © 2016 Elsevier B.V. All rights reserved.

Representational momentum in dynamic facial expressions is modulated by the level of expressed pain: Amplitude and direction effects.

PubMed

Prigent, Elise; Amorim, Michel-Ange; de Oliveira, Armando Mónica

2018-01-01

Humans have developed a specific capacity to rapidly perceive and anticipate other people's facial expressions so as to get an immediate impression of their emotional state of mind. We carried out two experiments to examine the perceptual and memory dynamics of facial expressions of pain. In the first experiment, we investigated how people estimate other people's levels of pain based on the perception of various dynamic facial expressions; these differ both in terms of the amount and intensity of activated action units. A second experiment used a representational momentum (RM) paradigm to study the emotional anticipation (memory bias) elicited by the same facial expressions of pain studied in Experiment 1. Our results highlighted the relationship between the level of perceived pain (in Experiment 1) and the direction and magnitude of memory bias (in Experiment 2): When perceived pain increases, the memory bias tends to be reduced (if positive) and ultimately becomes negative. Dynamic facial expressions of pain may reenact an "immediate perceptual history" in the perceiver before leading to an emotional anticipation of the agent's upcoming state. Thus, a subtle facial expression of pain (i.e., a low contraction around the eyes) that leads to a significant positive anticipation can be considered an adaptive process-one through which we can swiftly and involuntarily detect other people's pain.

[Influence of early childhood stress exposure and traumatic life events on pain perception].

PubMed

Tesarz, J; Gerhardt, A; Eich, W

2018-06-05

Adult pain perception is influenced substantially by interactions between mind, body, and social environment during early life. Early stress exposure and traumatic life events induce powerful psychophysical stress reactions that exert multiple neurofunctional processes. This has significant implications for pain perception and pain processing. As part of this review, the complex relationships between traumatic stress experiences and associated psychobiological mechanisms of chronic pain will be discussed. Based on selected studies, psychophysiological findings are presented and possible underlying mechanisms are discussed. The article concludes with a discussion of potential implications for treatment.

Allodynia mediated by C-tactile afferents in human hairy skin.

PubMed

Nagi, Saad S; Rubin, Troy K; Chelvanayagam, David K; Macefield, Vaughan G; Mahns, David A

2011-08-15

We recently showed a contribution of low-threshold cutaneous mechanoreceptors to vibration-evoked changes in the perception of muscle pain. Neutral-touch stimulation (vibration) of the hairy skin during underlying muscle pain evoked an overall increase in pain intensity, i.e. allodynia. This effect appeared to be dependent upon cutaneous afferents, as allodynia was abolished by intradermal anaesthesia. However, it remains unclear whether allodynia results from activation of a single class of cutaneous afferents or the convergence of inputs from multiple classes. Intriguingly, no existing human study has examined the contribution of C-tactile (CT) afferents to allodynia. Detailed psychophysical observations were made in 29 healthy subjects (18 males and 11 females). Sustained muscle pain was induced by infusing hypertonic saline (HS: 5%) into tibialis anterior muscle (TA). Sinusoidal vibration (200 Hz–200 μm) was applied to the hairy skin overlying TA. Pain ratings were recorded using a visual analogue scale (VAS). In order to evaluate the role of myelinated and unmyelinated cutaneous afferents in the expression of vibration-evoked allodynia, compression block of the sciatic nerve, and low-dose intradermal anaesthesia (Xylocaine 0.25%) were used, respectively. In addition, the modulation of muscle pain by gentle brushing (1.0 and 3.0 cm s(−1))--known to excite CT fibres--was examined. Brushing stimuli were applied to the hairy skin with all fibres intact and following the blockade of myelinated afferents. During tonic muscle pain (VAS 4–6), vibration evoked a significant and reproducible increase in muscle pain (allodynia) that persisted following compression of myelinated afferents. During compression block, the sense of vibration was abolished, but the vibration-evoked allodynia persisted. In contrast, selective anaesthesia of unmyelinated cutaneous afferents abolished the allodynia, whereas the percept of vibration remained unaffected. Furthermore, allodynia was preserved in the adjacent non-anaesthetized skin. Conformingly, gentle brushing produced allodynia (at both brushing speeds) that persisted during the blockade of myelinated afferents. Prior to the induction and following cessation of muscle pain, all subjects reported vibration and brushing as non-painful (VAS = 0). These results demonstrate that CT fibres in hairy skin mediate allodynia, and that CT-mediated inputs have a pluripotent central effect.

Evidence for a central mode of action for etoricoxib (COX-2 inhibitor) in patients with painful knee osteoarthritis.

PubMed

Arendt-Nielsen, Lars; Egsgaard, Line Lindhardt; Petersen, Kristian Kjær

2016-08-01

The COX-2 inhibitor etoricoxib modulates the peripheral and central nociceptive mechanisms in animals. This interaction has not been studied in patients with pain. This randomized, double-blind, placebo-controlled, 2-way crossover, 4-week treatment study investigated the pain mechanisms modulated by etoricoxib in patients with painful knee osteoarthritis. Patients were randomized to group A (60 mg/d etoricoxib followed by placebo) or B (placebo followed by 60 mg/d etoricoxib). The quantitative, mechanistic pain biomarkers were pressure pain thresholds, temporal summation (TS), and conditioning pain modulation. Clinical readouts were Brief Pain Inventory, WOMAC, painDETECT questionnaire (PD-Q), and time and pain intensity during walking and stair climbing. Etoricoxib as compared with placebo significantly modulated the pressure pain thresholds (P = 0.012, localized sensitization) at the knee and leg (control site) (P = 0.025, spreading sensitization) and TS assessed from the knee (P = 0.038) and leg (P = 0.045). Conditioning pain modulation was not modulated. The Brief Pain Inventory (pain scores), PD-Q, WOMAC, and walking and stair climbing tests were all significantly improved by etoricoxib. Based on a minimum of 30% or 50% pain alleviation (day 0-day 28), responders and nonresponders were defined. The nonresponders showed a significant association between increased facilitation of TS and increased pain alleviation. None of the other parameters predicted the degree of pain alleviation. Generally, a responder to etoricoxib has the most facilitated TS. In conclusion, etoricoxib (1) modulated central pain modulatory mechanisms and (2) improved pain and function in painful osteoarthritis. Stronger facilitation of TS may indicate a better response to etoricoxib, supporting the central mode-of-action of the drug.

Dissatisfaction with own body makes patients with eating disorders more sensitive to pain

PubMed Central

Yamamotova, Anna; Bulant, Josef; Bocek, Vaclav; Papezova, Hana

2017-01-01

Body image represents a multidimensional concept including body image evaluation and perception of body appearance. Disturbances of body image perception are considered to be one of the central aspects of anorexia nervosa and bulimia nervosa. There is growing evidence that body image distortion can be associated with changes in pain perception. The aim of our study was to examine the associations between body image perception, body dissatisfaction, and nociception in women with eating disorders and age-matched healthy control women. We measured body dissatisfaction and pain sensitivity in 61 patients with Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition diagnoses of eating disorders (31 anorexia nervosa and 30 bulimia nervosa) and in 30 healthy women. Thermal pain threshold latencies were evaluated using an analgesia meter and body image perception and body dissatisfaction were assessed using Anamorphic Micro software (digital pictures of their own body distorted into larger-body and thinner-body images). Patients with eating disorders overestimated their body size in comparison with healthy controls, but the two groups did not differ in body dissatisfaction. In anorexia and bulimia patient groups, body dissatisfaction (calculated in pixels as desired size/true image size) correlated with pain threshold latencies (r=0.55, p=0.001), while between body image perception (determined as estimation size/true image size) and pain threshold, no correlation was found. Thus, we demonstrated that in patients with eating disorders, pain perception is significantly associated with emotional contrary to sensory (visual) processing of one’s own body image. The more the patients desired to be thin, the more pain-sensitive they were. Our findings based on some shared mechanisms of body dissatisfaction and pain perception support the significance of negative emotions specific for eating disorders and contribute to better understanding of the psychosomatic characteristics of this spectrum of illnesses. PMID:28761371

Rational Basis for the Use of Bergamot Essential Oil in Complementary Medicine to Treat Chronic Pain.

PubMed

Rombolà, L; Amantea, D; Russo, R; Adornetto, A; Berliocchi, L; Tridico, L; Corasaniti, M T; Sakurada, S; Sakurada, T; Bagetta, G; Morrone, L A

2016-01-01

In complementary medicine, aromatherapy uses essential oils to improve agitation and aggression observed in dementia, mood, depression, anxiety and chronic pain. Preclinical research studies have reported that the essential oil obtained from bergamot (BEO) fruit (Citrus bergamia, Risso) modifies normal and pathological synaptic plasticity implicated, for instance, in nociceptive and neuropathic pain. Interestingly, recent results indicated that BEO modulates sensitive perception of pain in different models of nociceptive, inflammatory and neuropathic pain modulating endogenous systems. Thus, local administration of BEO inhibited the nociceptive behavioral effect induced by intraplantar injection of capsaicin or formalin in mice. Similar effects were observed with linalool and linalyl acetate, major volatile components of the phytocomplex, Pharmacological studies showed that the latter effects are reversed by local or systemic pretreatment with the opioid antagonist naloxone hydrochloride alike with naloxone methiodide, high affinity peripheral μ-opioid receptor antagonist. These results and the synergistic effect observed following systemic or intrathecal injection of an inactive dose of morphine with BEO or linalool indicated an activation of peripheral opioid system. Recently, in neuropathic pain models systemic or local administration of BEO or linalool induced antiallodynic effects. In particular, in partial sciatic nerve ligation (PSNL) model, intraplantar injection of the phytocomplex or linalool in the ipsilateral hindpaw, but not in the contralateral, reduced PSNL-induced extracellularsignal- regulated kinase (ERK) activation and mechanical allodynia. In neuropathic pain high doses of morphine are needed to reduce pain. Interestingly, combination of inactive doses of BEO or linalool with a low dose of morphine induced antiallodynic effects in mice. Peripheral cannabinoid and opioid systems appear to be involved in the antinociception produced by intraplantar injection of β -caryophyllene, present in different essential oils including BEO. The data gathered so far indicate that the essential oil of bergamot is endowed with antinociceptive and antiallodynic effects and contribute to form the rational basis for rigorous testing of its efficacy in complementary medicine.

Expectancy-induced placebo analgesia in children and the role of magical thinking.

PubMed

Krummenacher, Peter; Kossowsky, Joe; Schwarz, Caroline; Brugger, Peter; Kelley, John M; Meyer, Andrea; Gaab, Jens

2014-12-01

Expectations and beliefs shape the experience of pain. This is most evident in context-induced, placebo analgesia, which has recently been shown to interact with the trait of magical thinking (MT) in adults. In children, placebo analgesia and the possible roles that MT and gender might play as modulators of placebo analgesia have remained unexplored. Using a paradigm in which heat pain stimuli were applied to both forearms, we investigated whether MT and gender can influence the magnitude of placebo analgesia in children. Participants were 49 right-handed children (aged 6-9 years) who were randomly assigned-stratified for MT and gender-to either an analgesia-expectation or a control-expectation condition. For both conditions, the placebo was a blue-colored hand disinfectant that was applied to the children's forearms. Independent of MT, the placebo treatment significantly increased both heat pain threshold and tolerance. The threshold placebo effect was more pronounced for girls than boys. In addition, independent of the expectation treatment, low-MT boys showed a lower tolerance increase on the left compared to the right side. Finally, MT specifically modulated tolerance on the right forearm side: Low-MT boys showed an increase, whereas high-MT boys showed a decrease in heat pain tolerance. This study documented a substantial expectation-induced placebo analgesia response in children (girls > boys) and demonstrated MT and gender-dependent laterality effects in pain perception. The findings may help improve individualized pain management for children. The study documents the first experimental evidence for a substantial expectancy-induced placebo analgesia response in healthy children aged 6 to 9 years (girls > boys). Moreover, the effect was substantially higher than the placebo response typically found in adults. The findings may help improve individualized pain management for children. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

Self-regulation of brain activity in patients with postherpetic neuralgia: a double-blind randomized study using real-time FMRI neurofeedback.

PubMed

Guan, Min; Ma, Lijia; Li, Li; Yan, Bin; Zhao, Lu; Tong, Li; Dou, Shewei; Xia, Linjie; Wang, Meiyun; Shi, Dapeng

2015-01-01

A pilot study has shown that real-time fMRI (rtfMRI) neurofeedback could be an alternative approach for chronic pain treatment. Considering the relative small sample of patients recruited and not strictly controlled condition, it is desirable to perform a replication as well as a double-blinded randomized study with a different control condition in chronic pain patients. Here we conducted a rtfMRI neurofeedback study in a subgroup of pain patients - patients with postherpetic neuralgia (PHN) and used a different sham neurofeedback control. We explored the feasibility of self-regulation of the rostral anterior cingulate cortex (rACC) activation in patients with PHN through rtfMRI neurofeedback and regulation of pain perception. Sixteen patients (46-71 years) with PHN were randomly allocated to a experimental group (n = 8) or a control group (n = 8). 2 patients in the control group were excluded for large head motion. The experimental group was given true feedback information from their rACC whereas the control group was given sham feedback information from their posterior cingulate cortex (PCC). All subjects were instructed to perform an imagery task to increase and decrease activation within the target region using rtfMRI neurofeedback. Online analysis showed 6/8 patients in the experimental group were able to increase and decrease the blood oxygen level dependent (BOLD) fMRI signal magnitude during intermittent feedback training. However, this modulation effect was not observed in the control group. Offline analysis showed that the percentage of BOLD signal change of the target region between the last and first training in the experimental group was significantly different from the control group's and was also significantly different than 0. The changes of pain perception reflected by numerical rating scale (NRS) in the experimental group were significantly different from the control group. However, there existed no significant correlations between BOLD signal change and NRS change. Patients with PHN could learn to voluntarily control over activation in rACC through rtfMRI neurofeedback and alter their pain perception level. The present study may provide new evidence that rtfMRI neurofeedback training may be a supplemental approach for chronic clinical pain management.

Self-Regulation of Brain Activity in Patients with Postherpetic Neuralgia: A Double-Blind Randomized Study Using Real-Time fMRI Neurofeedback

PubMed Central

Li, Li; Yan, Bin; Zhao, Lu; Tong, Li; Dou, Shewei; Xia, Linjie; Wang, Meiyun; Shi, Dapeng

2015-01-01

Background A pilot study has shown that real-time fMRI (rtfMRI) neurofeedback could be an alternative approach for chronic pain treatment. Considering the relative small sample of patients recruited and not strictly controlled condition, it is desirable to perform a replication as well as a double-blinded randomized study with a different control condition in chronic pain patients. Here we conducted a rtfMRI neurofeedback study in a subgroup of pain patients – patients with postherpetic neuralgia (PHN) and used a different sham neurofeedback control. We explored the feasibility of self-regulation of the rostral anterior cingulate cortex (rACC) activation in patients with PHN through rtfMRI neurofeedback and regulation of pain perception. Methods Sixteen patients (46–71 years) with PHN were randomly allocated to a experimental group (n = 8) or a control group (n = 8). 2 patients in the control group were excluded for large head motion. The experimental group was given true feedback information from their rACC whereas the control group was given sham feedback information from their posterior cingulate cortex (PCC). All subjects were instructed to perform an imagery task to increase and decrease activation within the target region using rtfMRI neurofeedback. Results Online analysis showed 6/8 patients in the experimental group were able to increase and decrease the blood oxygen level dependent (BOLD) fMRI signal magnitude during intermittent feedback training. However, this modulation effect was not observed in the control group. Offline analysis showed that the percentage of BOLD signal change of the target region between the last and first training in the experimental group was significantly different from the control group’s and was also significantly different than 0. The changes of pain perception reflected by numerical rating scale (NRS) in the experimental group were significantly different from the control group. However, there existed no significant correlations between BOLD signal change and NRS change. Conclusion Patients with PHN could learn to voluntarily control over activation in rACC through rtfMRI neurofeedback and alter their pain perception level. The present study may provide new evidence that rtfMRI neurofeedback training may be a supplemental approach for chronic clinical pain management. PMID:25848773

Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing

PubMed Central

Goodin, Burel; Kindler, Lindsay L.; Caudle, Robert M.; Edwards, Robert R.; Gravenstein, Nikolaus; Riley, Joseph L.; Fillingim, Roger B.

2013-01-01

The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). Compared to baseline heat pain ratings, concurrent foot immersion lowered pain intensity ratings, which suggests an inhibitory effect, was reduced with naltrexone, suggesting at least partial dependence of inhibition on endogenous opioids. An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain. PMID:22534819

The influence of pain-related expectations on intensity perception of non-painful somatosensory stimuli.

PubMed

Zaman, Jonas; Wiech, Katja; Claes, Nathalie; Van Oudenhove, Lukas; Van Diest, Ilse; Vlaeyen, Johan W S

2018-04-03

The extent to which pain-related expectations, known to affect pain perception, also affect perception of non-painful sensations remains unclear, as well as the potential role of unpredictability in this context. In a proprioceptive fear conditioning paradigm, various arm extension movements were associated with predictable and unpredictable electrocutaneous pain or its absence. During a subsequent test phase non-painful electrocutaneous stimuli with a high or low intensity were presented during movement execution. We used hierarchical drift diffusion modeling to examine the influence of expecting pain on the perceptual decision-making process underlying intensity perception of non-painful sensations. In the first experiment (n=36), the pain stimulus was never presented during the test phase after conditioning. In the second experiment (n=39), partial reinforcement was adopted to prevent extinction of pain expectations. In both experiments, movements that were associated with (un)predictable pain led to higher pain-expectancy, self-reported fear, unpleasantness and arousal, as compared to movements that were never paired with pain (effect sizes ηp ranging from .119 - .557; all p-values < .05). Only in the second experiment - when the threat of the pain US remained present - we found that the expectation of pain affected decision-making. Compared to the no pain condition, an a priori decision-making bias towards the high intensity decision threshold was found with the strongest bias during unpredictable pain (effect sizes ηp ranging from .469 - .504; all p-values < .001). Thus, the expectation of pain not only affects inferential processes for subsequent painful but also for non-painful bodily stimuli, with unpredictability moderating these effects, and only when the threat of pain remains present due to partial reinforcement.

Age effects on pain thresholds, temporal summation and spatial summation of heat and pressure pain.

PubMed

Lautenbacher, Stefan; Kunz, Miriam; Strate, Peter; Nielsen, Jesper; Arendt-Nielsen, Lars

2005-06-01

Experimental data on age-related changes in pain perception have so far been contradictory. It has appeared that the type of pain induction method is critical in this context, with sensitivity to heat pain being decreased whereas sensitivity to pressure pain may be even enhanced in the elderly. Furthermore, it has been shown that temporal summation of heat pain is more pronounced in the elderly but it has remained unclear whether age differences in temporal summation are also evident when using other pain induction methods. No studies on age-related changes in spatial summation of pain have so far been conducted. The aim of the present study was to provide a comprehensive survey on age-related changes in pain perception, i.e. in somatosensory thresholds (warmth, cold, vibration), pain thresholds (heat, pressure) and spatial and temporal summation of heat and pressure pain. We investigated 20 young (mean age 27.1 years) and 20 elderly (mean age 71.6 years) subjects. Our results confirmed and extended previous findings by showing that somatosensory thresholds for non-noxious stimuli increase with age whereas pressure pain thresholds decrease and heat pain thresholds show no age-related changes. Apart from an enhanced temporal summation of heat pain, pain summation was not found to be critically affected by age. The results of the present study provide evidence for stimulus-specific changes in pain perception in the elderly, with deep tissue (muscle) nociception being affected differently by age than superficial tissue (skin) nociception. Summation mechanisms contribute only moderately to age changes in pain perception.

Sustained deep-tissue pain alters functional brain connectivity.

PubMed

Kim, Jieun; Loggia, Marco L; Edwards, Robert R; Wasan, Ajay D; Gollub, Randy L; Napadow, Vitaly

2013-08-01

Recent functional brain connectivity studies have contributed to our understanding of the neurocircuitry supporting pain perception. However, evoked-pain connectivity studies have employed cutaneous and/or brief stimuli, which induce sensations that differ appreciably from the clinical pain experience. Sustained myofascial pain evoked by pressure cuff affords an excellent opportunity to evaluate functional connectivity change to more clinically relevant sustained deep-tissue pain. Connectivity in specific networks known to be modulated by evoked pain (sensorimotor, salience, dorsal attention, frontoparietal control, and default mode networks: SMN, SLN, DAN, FCN, and DMN) was evaluated with functional-connectivity magnetic resonance imaging, both at rest and during a sustained (6-minute) pain state in healthy adults. We found that pain was stable, with no significant changes of subjects' pain ratings over the stimulation period. Sustained pain reduced connectivity between the SMN and the contralateral leg primary sensorimotor (S1/M1) representation. Such SMN-S1/M1 connectivity decreases were also accompanied by and correlated with increased SLN-S1/M1 connectivity, suggesting recruitment of activated S1/M1 from SMN to SLN. Sustained pain also increased DAN connectivity to pain processing regions such as mid-cingulate cortex, posterior insula, and putamen. Moreover, greater connectivity during pain between contralateral S1/M1 and posterior insula, thalamus, putamen, and amygdala was associated with lower cuff pressures needed to reach the targeted pain sensation. These results demonstrate that sustained pain disrupts resting S1/M1 connectivity by shifting it to a network known to process stimulus salience. Furthermore, increased connectivity between S1/M1 and both sensory and affective processing areas may be an important contribution to interindividual differences in pain sensitivity. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Pain perception and expression: the influence of gender, personal self-efficacy, and lifespan socialization.

PubMed

Miller, Carly; Newton, Sarah E

2006-12-01

There are differences between males and females regarding the perception, expression, and tolerance of pain that stems from a variety of social and psychologic influences. Personal self-efficacy and lifespan socialization are two such influences, and they provide new dimensions for nurses to better understand the pain experience. This article will present a review of the literature regarding personal self-efficacy and lifespan socialization and their effects on pain perception and expression among males and females. Finally, nursing implications related to the topic will be discussed.

Decreased ventral anterior cingulate cortex activity is associated with reduced social pain during emotional support.

PubMed

Onoda, Keiichi; Okamoto, Yasumasa; Nakashima, Ken'ichiro; Nittono, Hiroshi; Ura, Mitsuhiro; Yamawaki, Shigeto

2009-01-01

People feel psychological pain when they are excluded, and this pain is often attenuated when emotional support is received. It is therefore likely that a specific neural mechanism underlies the detection of social exclusion. Similarly, specific neural mechanisms may underlie the beneficial effects of emotional support. Although neuroimaging researchers have recently examined the neural basis of social pain, there is presently no agreement as to which part of the anterior cingulate cortex (ACC) is involved in the perception and modulation of social pain. We hypothesized that activity in those brain regions that are associated with social pain would be correlated with decrements in social pain induced by emotional support. To examine the effects of emotional support on social pain caused by exclusion, we conducted an fMRI study in which participants played a virtual ball-tossing game. Participants were initially included and later excluded from the game. In the latter half of the session from which participants were excluded, participants received emotionally supportive text messages. We found that emotional support led to increased activity in the left lateral/medial prefrontal cortices and some temporal regions. Those individuals who experienced greater attenuation of social pain exhibited lower ventral ACC and higher left lateral prefrontal cortex activation. These results suggest that the ventral ACC underlies social pain, and that emotional support enhances prefrontal cortex activity, which in turn may lead to a weakened affective response.

Emotional modulation of pain and spinal nociception in fibromyalgia.

PubMed

Rhudy, Jamie L; DelVentura, Jennifer L; Terry, Ellen L; Bartley, Emily J; Olech, Ewa; Palit, Shreela; Kerr, Kara L

2013-07-01

Fibromyalgia (FM) is characterized by widespread pain, as well as affective disturbance (eg, depression). Given that emotional processes are known to modulate pain, a disruption of emotion and emotional modulation of pain and nociception may contribute to FM. The present study used a well-validated affective picture-viewing paradigm to study emotional processing and emotional modulation of pain and spinal nociception. Participants were 18 individuals with FM, 18 individuals with rheumatoid arthritis (RA), and 19 healthy pain-free controls (HC). Mutilation, neutral, and erotic pictures were presented in 4 blocks; 2 blocks assessed only physiological-emotional reactions (ie, pleasure/arousal ratings, corrugator electromyography, startle modulation, skin conductance) in the absence of pain, and 2 blocks assessed emotional reactivity and emotional modulation of pain and the nociceptive flexion reflex (NFR, a physiological measure of spinal nociception) evoked by suprathreshold electric stimulations over the sural nerve. In general, mutilation pictures elicited displeasure, corrugator activity, subjective arousal, and sympathetic activation, whereas erotic pictures elicited pleasure, subjective arousal, and sympathetic activation. However, FM was associated with deficits in appetitive activation (eg, reduced pleasure/arousal to erotica). Moreover, emotional modulation of pain was observed in HC and RA, but not FM, even though all 3 groups evidenced modulation of NFR. Additionally, NFR thresholds were not lower in the FM group, indicating a lack of spinal sensitization. Together, these results suggest that FM is associated with a disruption of supraspinal processes associated with positive affect and emotional modulation of pain, but not brain-to-spinal cord circuitry that modulates spinal nociceptive processes. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

The role of pain catastrophizing in experimental pain perception.

PubMed

Kristiansen, Frederik L; Olesen, Anne E; Brock, Christina; Gazerani, Parisa; Petrini, Laura; Mogil, Jeffrey S; Drewes, Asbjørn M

2014-03-01

Pain is a subjective experience influenced by multiple factors, and tremendous variety within individuals is present. To evaluate emotional state of pain, catastrophizing score can be used. This study investigated pain catastrophizing ratings in association with experimental pain perception. Experimental pain was induced using thermal heat and cold stimulation of skin, mechanical stimulation of muscle and bone, and thermal, mechanical, and electrical stimulation of the gastrointestinal tract in healthy participants (N = 41). Prior to experimental sessions, a pain catastrophizing questionnaire was filled out by each participant. Based on the median catastophizing score, participants were divided into two groups: noncatastrophizers and low-catastrophizers. No significant difference was found between low-catastrophizers and noncatastrophizers in thermal heat stimulation of skin, mechanical stimulation of muscle and bone, and rectal electrical stimulation (All P > 0.05). Low-catastrophizers were more sensitive to visceral thermal stimulation (4.7%, P = 0.02) and visceral mechanical stimulation (29.7%, P = 0.03). For participants that completed the 120 seconds ice water stimulation, noncatastrophizers reported 13.8% less pain than low-catastrophizers (P = 0.02). A positive correlation between PCS score and pain perception on cold pressor test was found (r = 0.4, P = 0.02). By extrapolating data, further analysis of the total group was performed and no differences (both P > 0.05) were observed. Even small increments in pain catastrophizing score can influence pain perception to deep and tonic stimulations. Catatrophizing may partly explain the variability found in experimental pain studies. © 2013 World Institute of Pain.

Sustained deep-tissue pain alters functional brain connectivity

PubMed Central

Kim, Jieun; Loggia, Marco L.; Edwards, Robert; Wasan, Ajay D.; Gollub, Randy L.; Napadow, Vitaly

2013-01-01

Recent functional brain connectivity studies have contributed to our understanding of the neurocircuitry supporting pain perception. However, evoked-pain connectivity studies have employed cutaneous and/or brief stimuli, which induce sensations that differ appreciably from the clinical pain experience. Sustained myofascial pain evoked by pressure cuff affords an excellent opportunity to evaluate functional connectivity change to more clinically-relevant sustained deep-tissue pain. Connectivity in specific networks known to be modulated by evoked pain (sensorimotor, salience, dorsal attention, fronto-parietal control and default mode networks; SMN, SLN, DAN, FCN and DMN) was evaluated with functional-connectivity MRI, both at rest and during a sustained (6-minute) pain state in healthy adults. We found that pain was stable with no significant changes of subjects’ pain ratings over the stimulation period. Sustained pain reduced connectivity between the SMN and the contralateral leg primary sensorimotor (S1/M1) representation. Such SMN-S1/M1 connectivity decreases were also accompanied by and correlated with increased SLN-S1/M1 connectivity, suggesting recruitment of activated S1/M1 from SMN to SLN. Sustained pain also increased DAN connectivity to pain processing regions such as mid-cingulate cortex, posterior insula and putamen. Moreover, greater connectivity during pain between contralateral S1/M1 and posterior insula, thalamus, putamen, and amygdala, was associated with lower cuff pressures needed to reach the targeted pain sensation. These results demonstrate that sustained pain disrupts resting S1/M1 connectivity by shifting it to a network known to process stimulus salience. Furthermore, increased connectivity between S1/M1 and both sensory and affective processing areas may be an important contribution to inter-individual differences in pain sensitivity. PMID:23718988

Emotional modulation of pain and spinal nociception in fibromyalgia

PubMed Central

Rhudy, Jamie L.; DelVentura, Jennifer L.; Terry, Ellen L.; Bartley, Emily J.; Olech, Ewa; Palit, Shreela; Kerr, Kara L.

2013-01-01

Fibromyalgia (FM) is characterized by widespread pain, as well as affective disturbance (e.g., depression). Given that emotional processes are known to modulate pain, a disruption of emotion and emotional modulation of pain and nociception may contribute to FM. The present study used a well-validated affective picture-viewing paradigm to study emotional processing and emotional modulation of pain and spinal nociception. Participants were 18 individuals with FM, 18 individuals with rheumatoid arthritis (RA), and 19 healthy pain-free controls (HC). Mutilation, neutral, and erotic pictures were presented in four blocks; two blocks assessed only physiological-emotional reactions (i.e., pleasure/arousal ratings, corrugator EMG, startle modulation, skin conductance) in the absence of pain and two blocks assessed emotional reactivity and emotional modulation of pain and the nociceptive flexion reflex (NFR, a physiological measure of spinal nociception) evoked by suprathreshold electric stimulations over the sural nerve. In general, mutilation pictures elicited displeasure, corrugator activity, subjective arousal, and sympathetic activation, whereas erotic pictures elicited pleasure, subjective arousal, and sympathetic activation. However, FM was associated with deficits in appetitive activation (e.g., reduced pleasure/arousal to erotica). Moreover, emotional modulation of pain was observed in HC and RA, but not FM, even though all three groups evidenced modulation of NFR. Additionally, NFR thresholds were not lower in the FM group, indicating a lack of spinal sensitization. Together, these results suggest that FM is associated with a disruption of supraspinal processes associated with positive affect and emotional modulation of pain, but not brain-to-spinal cord circuitry that modulates spinal nociceptive processes. PMID:23622762

An observational study of the impact of genetic testing for pain perception in the clinical management of chronic non-cancer pain.

PubMed

Sharma, Maneesh; Kantorovich, Svetlana; Lee, Chee; Anand, Natasha; Blanchard, John; Fung, Eric T; Meshkin, Brian; Brenton, Ashley; Richeimer, Steven

2017-06-01

Pain levels are a key metric in clinical care. However, the assessment of pain is limited to basic questionnaires and physician interpretation, which yield subjective data. Genetic markers of pain sensitivity, such as single nucleotide polymorphisms in the catechol-O-methyltransferase gene, have been shown to be associated with pain perception and have been used to provide objective information about a patient's pain. The goal of this study was to determine if physician treatment adjustments based on genetic tests of pain perception resulted in improved outcomes for patients. A prospective, longitudinal study was conducted with 134 chronic non-cancer pain patients genotyped for pain perception-related catechol-O-methyltransferase haplotypes. Physicians were provided with patients' results and asked to document 1) their assessment of benefit of the genetic test; 2) treatment changes made based on the genetic test; and 3) patient clinical responses to changes implemented. Based on genetic testing results, physicians adjusted treatment plans for 40% of patients. When medication changes were made based on genetic testing results, 72% of patients showed improvement in clinical status. When non-pharmacological actions were performed, 69% of physicians felt their patients' clinical status improved. Moreover, physicians believed the genetic test results were consistent with patient pain levels in 85% of cases. These results demonstrate that providing personalized medicine with genetic information related to pain perception affected physician clinical decision-making for a substantial proportion of patients in this study, and that the availability and utilization of this information was a contributing factor in clinical improvement. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Effect of oxytocin on human pain perception].

PubMed

Pfeifer, A-C; Ditzen, B; Neubauer, E; Schiltenwolf, M

2016-10-01

Over the years the effect of the neuropeptide oxytocin and its possible utilization for pain management has been increasingly more investigated and discussed. Initial results emphasized the effects of oxytocin with respect to labor and breastfeeding. Diverse animals studies were also able to demonstrate the effectiveness of the peptide in attachment behavior and pain perception; however, it is still unclear how oxytocin affects pain perception in humans. The potential therapeutic effectiveness of oxytocin could be particularly important for primary and secondary treatment of pain patients because chronification of pain can occur more frequently in this area. For this review the databases PubMed, Medline und PsycINFO were searched using the terms oxytocin, pain, human and analgesic. The search resulted in a total of 89 original articles after excluding articles regarding labor pain, breastfeeding and animal studies. Only those studies were included which were carried out between 1994 and 2015. A total of 17 articles remained for inclusion in this review and included 13 studies on the exogenous application of oxytocin and 4 on measurement of oxytocin levels in plasma. This review article gives a summary of the current state of research on oxytocin and its direct and indirect association with human pain perception and emphasizes its relevance for the multimodal management of pain.

Complex regional pain syndrome (CRPS) impairs visuospatial perception,whereas post-herpetic neuralgia does not: possible implications for supraspinal mechanism of CRPS.

PubMed

Uematsu, Hironobu; Sumitani, Masahiko; Yozu, Arito; Otake, Yuko; Shibata, Masahiko; Mashimo, Takashi; Miyauchi, Satoru

2009-11-01

Complex regional pain syndrome (CRPS) patients show impaired visuospatial perception in the dark, as compared to normal patients with acute nociceptive pain. The purpose of this study is 2-fold: (i) to ascertain whether this distorted visuospatial perception is related to the chronicity of pain, and (ii) to analyse visuospatial perception of CRPS in comparison with another neuropathic pain condition. We evaluated visual subjective body-midline (vSM) representation in 27 patients with post-herpetic neuralgia (PHN) and 22 with CRPS under light and dark conditions. A red laser dot was projected onto a screen and moved horizontally towards the sagittal plane of the objective body-midline (OM). Each participant was asked to direct the dot to a position where it crossed their vSM. The distance between the vSM and OM was analysed to determine how and in which direction the vSM deviated. Under light condition, all vSM judgments approximately matched the OM. However, in the dark, CRPS patients, but not PHN patients, showed a shifted vSM towards the affected side. We demonstrated that chronic pain does not always impair visuospatial perception. The aetiology of PHN is limited to the peripheral nervous system, whereas the distorted visuospatial perception suggests a supraspinal aetiology of CRPS.

The Role of the Brain's Endocannabinoid System in Pain and Its Modulation by Stress.

PubMed

Corcoran, Louise; Roche, Michelle; Finn, David P

2015-01-01

Stress has a complex, bidirectional modulatory influence on pain. Stress may either reduce (stress-induced analgesia) or exacerbate (stress-induced hyperalgesia) pain depending on the nature, duration, and intensity of the stressor. The endogenous cannabinoid (endocannabinoid) system is present throughout the neuroanatomical pathways that mediate and modulate responses to painful stimuli. The specific role of the endocannabinoid system in the brain in pain and the modulation of pain by stress is reviewed herein. We first provide a brief overview of the endocannabinoid system, followed by a review of the evidence that the brain's endocannabinoid system modulates pain. We provide a comprehensive evaluation of the role of the endocannabinoid system supraspinally, and particularly in the rostral ventromedial medulla, periaqueductal gray, amygdala, and prefrontal cortex, in pain, stress-induced analgesia, and stress-induced hyperalgesia. Increased understanding of endocannabinoid-mediated regulation of pain and its modulation by stress will inform the development of novel therapeutic approaches for pain and its comorbidity with stress-related disorders. © 2015 Elsevier Inc. All rights reserved.

Deliberate or unintended: Intentions modulate empathic responses to others' economic payoffs in social interactions.

PubMed

Ma, Qingguo; Meng, Liang; Shen, Qiang

2017-12-01

Previous studies examining empathy have revealed the neural substrates of how the physical pain of others is represented in the human brain. However, little is known about the empathic modulation of behavioral and neural responses to others' economic payoffs, especially in the social context. In the present study, we engaged participants in a revised Dictator Game as observers who observe the powerless players receiving varied offers proposed by the dominant players, establishing the link between empathy and fairness perception. Results showed that unfair division schemes elicited a more pronounced FRN than fair ones only if a human agent proposed the initial offer. In addition, observers sacrificed their own payments to adjust unfair proposals, especially when a human agent proposed the offer. Thus, results of the current study demonstrated that perceived intention modulates behavioral and neural responses to others' economic payoffs in social interactions.

Opposite Effects of Stress on Pain Modulation Depend on the Magnitude of Individual Stress Response.

PubMed

Geva, Nirit; Defrin, Ruth

2018-04-01

The effect of acute stress on pain threshold and intolerance threshold are reported as producing either hypoalgesia or hyperalgesia. Yet, the contribution of individual stress reactivity in this respect has not been established. The aim was to test 2 pain modulation paradigms under acute stress manipulation, to our knowledge, for the first time, to study whether stress differentially affects pain modulation, and whether the effect is related to individual stress response. Participants were 31 healthy subjects. Conditioned pain modulation (CPM) and pain adaptation were measured before and after inducing an acute stress response using the Montreal Imaging Stress Task. Subjects' stress response was evaluated according to salivary cortisol, autonomic function, and perceived stress and anxiety. The Montreal Imaging Stress Task induced a validated stress response. On a group level, stress induced reduction in CPM magnitude and increase in pain adaptation compared with baseline. These responses correlated with stress reactivity. When the group was subdivided according to stress reactivity, only high stress responders exhibited reduced CPM whereas only low stress responders exhibited increased pain adaptation. The results suggest that acute stress may induce opposite effects on pain modulation, depending on individual stress reactivity magnitude, with an advantage to low stress responders. This study evaluated the effect of acute stress on pain modulation. Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders. Identification of high stress responders may promote better pain management. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

A preliminary study on how hypohydration affects pain perception.

PubMed

Bear, Tracey; Philipp, Michael; Hill, Stephen; Mündel, Toby

2016-05-01

Chronic pain is a prevalent health issue with one in five people suffering from some form of chronic pain, with loss of productivity and medical costs of chronic pain considerable. However, the treatment of pain can be difficult, as pain perception is complex and can be affected by factors other than tissue damage. This study investigated the effect of hypohydration (mild, voluntary dehydration from ∼24 h of limiting fluid intake, mimicking someone drinking less than usual) on a person's pain perception. Seventeen healthy males (age 27 ± 5 years) visited the laboratory on three occasions, once as a familiarization and then twice again while either euhydrated (urine specific gravity: 1.008 ± 0.005) or hypohydrated (urine specific gravity: 1.024 ± 0.003, and -1.4 ± 0.9% body mass). Each visit, they performed a cold pressor test, where their feet were placed in cold water (0-3 °C) for a maximum of 4 min. Measures of hydration status, pain sensitivity, pain threshold, and catastrophization were taken. We found that hypohydration predicted increased pain sensitivity (β = 0.43), trait pain catastrophizing, and baseline pain sensitivity (β = 0.37 and 0.47, respectively). These results are consistent with previous research, and suggest that a person's hydration status may be an important factor in their perception of acute pain. © 2016 Society for Psychophysiological Research.

Determinants of pain perception after external cephalic version in pregnant women.

PubMed

Truijens, Sophie E M; van der Zalm, Marieke; Pop, Victor J M; Kuppens, Simone M I

2014-03-01

A considerable proportion of pregnant women with a fetus in breech position refuses external cephalic version (ECV), with fear of pain as important barrier. As a consequence, they are at high risk for caesarean section at term. The current study investigated determinants of pain perception during ECV, with special attention to maternal mental state such as depression and fear of ECV. Prospective study of 249 third-trimester pregnant women with breech position with a request for an ECV attempt. Department of Obstetrics and Gynaecology in a large teaching hospital in the Netherlands. Prior to the ECV attempts, obstetric factors were registered, participants fulfilled the Edinburgh Depression Scale (EDS) and reported fear of ECV on a 10-point visual analog scale. Perception of pain intensity was measured with a 10-point visual analog scale, immediately after ECV. Multivariate linear regression analyses showed success of ECV to be the strongest predictor of pain perception. Furthermore, scores on the depression questionnaire and degree of fear of ECV independently explained pain perception, which was not the case for obstetrical or ECV related factors. Apart from ECV outcome, psychological factors like depression and fear of ECV were independently related to pain perception of an ECV attempt. Maternal mood state should be taken into account when offering an ECV attempt to women with a fetus in breech position. Due to the painful experience and the importance of successful outcome, ECV should only be attempted in institutions with experienced practitioners and with careful attention to maternal mood and the way a woman is coping with the ECV attempt. © 2013 Published by Elsevier Ltd.

What Influences How Patients Rate Their Hospital After Total Knee Arthroplasty?

PubMed

Chughtai, Morad; Jauregui, Julio J; Mistry, Jaydev B; Elmallah, Randa K; Diedrich, Aloise M; Bonutti, Peter M; Delanois, Ronald; Mont, Michael A

2016-04-01

There is increasing pressure from Centers for Medicare and Medicaid Services (CMS) to report quality measures for all hospitalizations. These quality measures are determined based on results from satisfaction surveys, such as Press Ganey® (PG) (Press Ganey® Performance Solutions, Wakefield, Massachusetts). Included in this particular survey element are questions regarding staff, including nurses and doctors, as well as items such as pain control. The results of these surveys will dictate the amount doctors are compensated for their services. Therefore, this study was undertaken to evaluate the effect of treating orthopaedists and nurses, as well as pain control, on PG surveys in patients who underwent total knee arthroplasty (TKA). Specifically, we aimed to ascertain the effect of these factors on how post-TKA patients perceive: 1) their orthopaedist, and 2) their overall surgical experience. We queried the Press Ganey® Database for all patients who underwent a TKA at our institution between November 2009 and January 2015. A weighted mean of question domains was utilized since each had multiple questions. In order to assess if pain management influences orthopaedist perception, a correlation analysis was performed between pain control and perception. In order to assess the influence of pain management on surgical experience, we performed a correlation analysis between pain control and overall hospital rating. A multiple regression analysis was performed using the hospital rating as the dependent variable to determine the most influential factors on surgical experience. Our analysis demonstrated a significantly positive correlation between patient perception of their pain control and their orthopaedist. There was a significant positive correlation between patient's perception of their pain control and their overall surgical experience. Multiple regression analysis using overall surgical experience as the dependent variable demonstrated a significant positive influence of perception of nurses and orthopaedists. Pain management positively influenced surgical experience; however, this was not significant. We found that perception of pain control in post-TKA patients affects perception of the treating orthopaedists, as well as their overall surgical experience. In addition, perception of orthopaedists and nurses both outweigh perception of pain control on overall surgical experience, with nurses being the most important. Orthopaedists should focus on staff education-particularly nurses-and educate them in order to optimize results on PG surveys and, ultimately, improve patient satisfaction. Further studies should correlate current standardized scoring systems and questionnaires for TKA with PG surveys in order to recognize gaps that need to be bridged to improve post-TKA patient satisfaction.

Validated Measures of Illness Perception and Behavior in People with Knee Pain and Knee Osteoarthritis: A Scoping Review.

PubMed

Hamilton, Clayon B; Wong, Ming-Kin; Gignac, Monique A M; Davis, Aileen M; Chesworth, Bert M

2017-01-01

To identify validated measures that capture illness perception and behavior and have been used to assess people who have knee pain/osteoarthritis. A scoping review was performed. Nine electronic databases were searched for records from inception through April 19, 2015. Search terms included illness perception, illness behavior, knee, pain, osteoarthritis, and their related terms. This review included English language publications of primary data on people with knee pain/osteoarthritis who were assessed with validated measures capturing any of 4 components of illness perception and behavior: monitor body, define and interpret symptoms, take remedial action, and utilize sources of help. Seventy-one publications included relevant measures. Two reviewers independently coded and analyzed each relevant measure within the 4 components. Sixteen measures were identified that capture components of illness perception and behavior in the target population. These measures were originally developed to capture constructs that include coping strategies/skills/styles, illness belief, illness perception, self-efficacy, and pain behavior. Coding results indicated that 5, 11, 12, and 5 of these measures included the monitor body, define and interpret symptoms, take remedial action, and utilize sources of help components, respectively. Several validated measures were interpreted as capturing some components, and only 1 measure was interpreted as capturing all of the components of illness perception and behavior in the target population. A measure that comprehensively captures illness perception and behavior could be valuable for informing and evaluating therapy for patients along a continuum of symptomatic knee osteoarthritis. © 2016 World Institute of Pain.

Stress perception and social indicators for low back, shoulder and joint pains in Japan: national surveys in 1995 and 2001.

PubMed

Takeuchi, Takeaki; Nakao, Mutsuhiro; Nishikitani, Mariko; Yano, Eiji

2004-07-01

This study aims to clarify the effects of stress perception and related social indicators on three major musculoskeletal symptoms: low back, shoulder, and joint pains in a Japanese population. Twenty health-related variables (stress perception and 19 social indicators) and the three symptoms were obtained from the following Japanese national surveys: the Comprehensive Survey of Living Condition of the People on Health and Welfare, the System of Social and Demographic Statistics of Japan, and the Statistical Report on Health Administration Services. The results were compared among 46 Japanese prefectures in 1995 and 2001. By factor analysis, the 19 indicators were classified into three factors of urbanization, aging and life-regularity, and individualization. The prevalence of stress perception was significantly correlated to the 8 indicators of urbanization factor. Although simple correlation analysis revealed a significant relationship of stress perception only to shoulder pain (in both years) and low back pain (in 2001), the results of multiple regression analysis showed that stress perception and some urbanization factors were significantly associated with all the three symptoms in both years exclusive of joint pain in 1995. Taking the effects of urbanization into consideration, stress perception seems to be closely related to the complaints of musculoskeletal symptoms in Japan.

Some Words Hurt More Than Others: Semantic Activation of Pain Concepts in Memory and Subsequent Experiences of Pain.

PubMed

Swannell, Ellen R; Brown, Christopher A; Jones, Anthony K P; Brown, Richard J

2016-03-01

Theory suggests that as activation of pain concepts in memory increases, so too does subsequent pain perception. Previously, researchers have found that activating pain concepts in memory increases pain perception of subsequent painful stimuli, relative to neutral information. However, they have not attempted to quantify the nature of the association between information studied and ensuing pain perception. We subliminally presented words that had either a low or high degree of association to the word 'pain,' although this was only partially successful and some words were consciously perceived. Participants then received randomized laser heat stimuli, delivered at 1 of 3 intensity levels (low, moderate, high), and we measured the effect of this on behavioral and electrophysiological measures of pain. Participants (N = 27) rated moderate- and high-intensity laser stimuli as more painful after viewing high relative to low associates of pain; these effects remained present when we controlled for measures of mood, anxiety, and physical symptom reporting. Similar effects were observed physiologically, with higher stimulus negativity preceding after high relative to low associates and greater amplitudes for the N2 component of the laser-evoked potential after presentation of high associates in the moderate and high laser intensity conditions. These data support activation-based models of the effects of memory on pain perception. Consistent with current theories of memory and pain, we found that high, relative to low activation of pain concepts in memory increased psychological and physiological responses to laser-induced pain. The effect remained regardless of whether participants showed conscious awareness of activation. Theoretical and clinical implications are discussed. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Polysomnographic Measurement of Sleep Duration and Bodily Pain Perception in the Sleep Heart Health Study.

PubMed

Weingarten, Jeremy A; Dubrovsky, Boris; Basner, Robert C; Redline, Susan; George, Liziamma; Lederer, David J

2016-08-01

To determine whether total sleep time (TST) and specific sleep stage duration are associated with bodily pain perception and whether sex, age, or subjective sleepiness modifies this relationship. Data from adults ages 39-90 y (n = 5,199) who took part in the Sleep Heart Health Study Exam 1 were analyzed. TST, rapid eye movement (REM) sleep time, and slow wave sleep (SWS) time were measured by unattended, in-home nocturnal polysomnography. Bodily pain perception was measured via the Short Form-36 questionnaire bodily pain component. We used logistic regression to examine associations between total and individual sleep stage durations and bodily pain perception controlling for age, sex, race, body mass index, apnea-hypopnea index, antidepressant use, and important cardiovascular conditions (smoking [pack-years], history of diabetes, and history of percutaneous coronary intervention and/or coronary artery bypass graft). In the fully adjusted model, REM sleep time and SWS time were not associated with "moderate to severe pain," whereas TST was: Each 1-h decrement in TST was associated with a 7% increased odds of "moderate to severe pain" (odds ratio 1.07, 95% confidence interval 1.002, 1.14). Due to modification of the association between SWS time and "moderate to severe pain" by sex (P for interaction = 0.01), we performed analyses stratified by sex: Each 1-h decrement in SWS time was associated with a 20% higher odds of "moderate to severe pain" among men (odds ratio 1.20, 95% confidence interval 1.03-1.42) whereas an association was not observed among women. Shorter TST among all subjects and shorter SWS time in men was associated with "moderate to severe pain." REM sleep time was not associated with bodily pain perception in this cohort. © 2016 Associated Professional Sleep Societies, LLC.

Pap Screening Goals and Perceptions of Pain among Black, Latina, and Arab Women: Steps toward Breaking down Psychological Barriers

PubMed Central

Gauss, Julie W.; Mabiso, Athur; Williams, Karen Patricia

2013-01-01

BACKGROUND Understanding women’s psychological barriers to getting Papanicolaou (Pap) screening has potential to impact cancer disparities. This study examined pain perceptions of Pap testing among Black, Latina and Arab women and goal setting to receive Pap tests. METHODS Data on 420 women, a longitudinal study, were analyzed using Chi-square tests of differences and generalized linear mixed models. RESULTS At baseline, 30.3% of Black and 35.5% of Latina women perceived Pap tests to be very painful compared to 24.2% of Arab women. Perceptions of pain influenced goal settings, such as scheduling a first ever Pap test (Odds ratio = 0.58, 95% Confidence interval: 0.14-0.94). Immediately following the intervention, women’s perception that Pap tests are very painful significantly declined (P-value<0.001) with Arab and Black women registering the greatest improvements (20.3 and 17.3 percent reduction, respectively compared to 8.4 percent for Latina). CONCLUSIONS Having the perception that the Pap test is very painful significantly reduces the likelihood of Black, Latina and Arab women setting the goal to schedule their first ever Pap test. Latina women are the least likely to improve their perception that the Pap test is very painful, though national statistics show they have the highest rates of morbidity and mortality from cervical cancer. These findings are instructive for designing tailored interventions to break down psychological barriers to Pap screening among underserved women. PMID:23288606

“Let’s Talk about OA Pain”: A Qualitative Analysis of the Perceptions of People Suffering from OA. Towards the Development of a Specific Pain OA-Related Questionnaire, the Osteoarthritis Symptom Inventory Scale (OASIS)

PubMed Central

Cedraschi, Christine; Delézay, Sylvie; Marty, Marc; Berenbaum, Francis; Bouhassira, Didier; Henrotin, Yves; Laroche, Françoise; Perrot, Serge

2013-01-01

Introduction Pain is the primary outcome measurement in osteoarthritis, and its assessment is mostly based on its intensity. The management of this difficult chronic condition could be improved by using pain descriptors to improve analyses of painful sensations. This should help to define subgroups of patients based on pain phenotype, for more adapted treatment. This study draws upon patients’ descriptions of their pain, to identify and understand their perception of osteoarthritis pain and to categorize pain dimensions. Methods This qualitative study was conducted with representative types of patients suffering from osteoarthritis. Two focus groups were conducted with a sample of 14 participants, with either recent or chronic OA, at one or multiple sites. Focus groups were semi-structured and used open-ended questions addressing personal experiences to explore the experiences of patients with OA pain and the meanings they attributed to these pains. Results Two main points emerged from content analyses: -A major difficulty in getting patients to describe their osteoarthritis pain: perception that nobody wants to hear about it; necessity to preserve one’s self and social image; notion of self-imposed stoicism; and perception of osteoarthritis as a complex, changing, illogical disease associated with aging. -Osteoarthritis pains were numerous and differed in intensity, duration, depth, type of occurrence, impact and rhythm, but also in painful sensations and associated symptoms. Based on analyses of the verbatim interviews, seven dimensions of OA pain emerged: pain sensory description, OA-related symptoms, pain variability profile, pain-triggering factors, pain and physical activity, mood and image, general physical symptoms. Summary In osteoarthritis, pain analysis should not be restricted to intensity. Our qualitative study identified pain descriptors and defined seven dimensions of osteoarthritis pain. Based on these dimensions, we aim to develop a specific questionnaire on osteoarthritis pain quality for osteoarthritis pain phenotyping: the OsteoArthritis Symptom Inventory Scale (OASIS). PMID:24244589

Dopamine D3 receptor knockout mice exhibit abnormal nociception in a sex-different manner.

PubMed

Liu, Peng; Xing, Bo; Chu, Zheng; Liu, Fei; Lei, Gang; Zhu, Li; Gao, Ya; Chen, Teng; Dang, Yong-Hui

2017-07-01

Pain is a complex and subjective experience. Previous studies have shown that mice lacking the dopamine D3 receptor (D3RKO) exhibit hypoalgesia, indicating a role of the D3 receptor in modulation of nociception. Given that there are sex differences in pain perception, there may be differences in responses to nociceptive stimuli between male and female D3RKO mice. In the current study, we examined the role of the D3 receptor in modulating nociception in male and female D3RKO mice. Acute thermal pain was modeled by hot-plate test. This test was performed at different temperatures including 52°C, 55°C, and 58°C. The von Frey hair test was applied to evaluate mechanical pain. And persistent pain produced by peripheral tissue injury and inflammation was modeled by formalin test. In the hot-plate test, compared with wild-type (WT) mice, D3RKO mice generally exhibited longer latencies at each of the three temperatures. Specially, male D3RKO mice showed hypoalgesia compared with male WT mice when the temperature was 55°C, while for the female mice, there was a statistical difference between genotypes when the test condition was 52°C. In the von Frey hair test, both male and female D3RKO mice exhibited hypoalgesia. In the formalin test, the male D3RKO mice displayed a similar nociceptive behavior as their sex-matched WT littermates, whereas significantly depressed late-phase formalin-induced nociceptive behaviors were observed in the female mutants. These findings indicated that the D3 receptor affects nociceptive behaviors in a sex-specific manner and that its absence induces more analgesic behavior in the female knockout mice. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Perceptions and practices of Finnish dairy producers on disbudding pain in calves.

PubMed

Hokkanen, A-H; Wikman, I; Korhonen, T; Pastell, M; Valros, A; Vainio, O; Hänninen, L

2015-02-01

Disbudding causes pain-related distress and behavioral changes in calves. Local anesthesia and non-steroidal anti-inflammatory drugs are effective for treating disbudding-related pain. Dairy producers play a key role in whether or not calves to be disbudded are properly medicated. Pain and distress related to disbudding of calves often remains untreated. Thus, we conducted this study to characterize perceptions and practices of dairy producers on disbudding and disbudding-related pain management. A questionnaire was sent to 1,000 randomly selected Finnish dairy producers (response rate: 45%). Our aim was to investigate producer perceptions about disbudding-related pain, the perceived need for pain alleviation before disbudding, and how these perceptions affect the valuing and use of pain alleviation before disbudding. More than 70% of Finnish dairy farms disbud their calves. Producers who ranked disbudding-related pain and need for pain alleviation higher called a veterinarian to medicate calves before disbudding more often than producers who ranked disbudding pain and need for pain alleviation lower. Among respondents who disbudded calves on their farms, 69% stated that disbudding caused severe pain, 63% stated that pain alleviation during disbudding is important, and 45% always had a veterinarian medicate their calves before disbudding. Producers with a herd healthcare agreement with their veterinarian estimated disbudding-related pain to be higher and had a veterinarian medicate calves more often than producers without such an agreement. Producers with tiestall systems and producers who did not use disbudding valued pain alleviation prior to disbudding higher than producers with freestalls and producers who used disbudding. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Basic science of pain.

PubMed

DeLeo, Joyce A

2006-04-01

The origin of the theory that the transmission of pain is through a single channel from the skin to the brain can be traced to the philosopher and scientist René Descartes. This simplified scheme of the reflex was the beginning of the development of the modern doctrine of reflexes. Unfortunately, Descartes' reflex theory directed both the study and treatment of pain for more than 330 years. It is still described in physiology and neuroscience textbooks as fact rather than theory. The gate control theory proposed by Melzack and Wall in 1965 rejuvenated the field of pain study and led to further investigation into the phenomena of spinal sensitization and central nervous system plasticity, which are the potential pathophysiologic correlates of chronic pain. The processing of pain takes place in an integrated matrix throughout the neuroaxis and occurs on at least three levels-at peripheral, spinal, and supraspinal sites. Basic strategies of pain control monopolize on this concept of integration by attenuation or blockade of pain through intervention at the periphery, by activation of inhibitory processes that gate pain at the spinal cord and brain, and by interference with the perception of pain. This article discusses each level of pain modulation and reviews the mechanisms of action of opioids and potential new analgesics. A brief description of animal models frames a discussion about recent advances regarding the role of glial cells and central nervous system neuroimmune activation and innate immunity in the etiology of chronic pain states. Future investigation into the discovery and development of novel, nonopioid drug therapy may provide needed options for the millions of patients who suffer from chronic pain syndromes, including syndromes in which the pain originates from peripheral nerve, nerve root, spinal cord, bone, muscle, and disc.

Pain perception studies in tension-type headache.

PubMed

Bezov, David; Ashina, Sait; Jensen, Rigmor; Bendtsen, Lars

2011-02-01

Tension-type headache (TTH) is a disorder with high prevalence and significant impact on society. Understanding of pathophysiology of TTH is paramount for development of effective treatments and prevention of chronification of TTH. Our aim was to review the findings from pain perception studies of pathophysiology of TTH as well as to review the research of pathophysiology of TTH. Pain perception studies such as measurement of muscle tenderness, pain detection thresholds, pain tolerance thresholds, pain response to suprathreshold stimulation, temporal summation and diffuse noxious inhibitory control (DNIC) have played a central role in elucidating the pathophysiology of TTH. It has been demonstrated that continuous nociceptive input from peripheral myofascial structures may induce central sensitization and thereby chronification of the headache. Measurements of pain tolerance thresholds and suprathreshold stimulation have shown presence of generalized hyperalgesia in chronic tension-type headache (CTTH) patients, while DNIC function has been shown to be reduced in CTTH. One imaging study showed loss of gray matter structures involved in pain processing in CTTH patients. Future studies should aim to integrate pain perception and imaging to confirm this finding. Pharmacological studies have shown that drugs like tricyclic anti-depressant amitriptyline and nitric oxide synthase inhibitors can reverse central sensitization and the chronicity of headache. Finally, low frequency electrical stimulation has been shown to rapidly reverse central sensitization and may be a new modality in treatment of CTTH and other chronic pain disorders. © 2010 American Headache Society.

Is appreciation of written education about pain neurophysiology related to changes in illness perceptions and health status in patients with fibromyalgia?

PubMed

van Ittersum, M W; van Wilgen, C P; Groothoff, J W; van der Schans, C P

2011-11-01

To investigate the appreciation of written education about pain neurophysiology in patients with fibromyalgia (FM) and its effects on illness perceptions and perceived health status. A booklet explaining pain neurophysiology was sent to participants with FM. Appreciation was assessed with 10 questions addressing relevance (0-30) and reassurance (0-30). Illness perceptions, catastrophizing and health status were measured with the Revised Illness Perception Questionnaire (IPQ-R), the Pain Catastrophizing Scale (PCS) and the Fibromyalgia Impact Questionnaire (FIQ) at baseline (T0), after a 2-week control period (T1) and 6 weeks after the intervention (T2). Forty-one patients participated. Mean (SD) scores for relevance and reassurance were 21.6 (5.6) and 18.7 (5.7), respectively. Only illness coherence, emotional representations, pain and fatigue changed significantly between T0 and T2. Correlations between appreciation and changes in outcomes ranged between r=0.00 and r=0.34. Although a majority of subjects appreciated the written information, it did not have clinically relevant effects on illness perceptions, catastrophizing or impact of FM on daily life. Written education about pain neurophysiology is inadequate toward changing illness perceptions, catastrophizing or perceived health status of participants with FM; education should be incorporated into a broader multidisciplinary self-management program. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Racial Bias in Neural Response for Pain Is Modulated by Minimal Group

PubMed Central

Shen, Fengtao; Hu, Yang; Fan, Mingxia; Wang, Huimin; Wang, Zhaoxin

2018-01-01

Whether empathic racial bias could be modulated is a subject of intense interest. The present study was carried out to explore whether empathic racial bias for pain is modulated by minimal group. Chinese/Western faces with neutral expressions receiving painful (needle penetration) or non-painful (Q-tip touch) stimulation were presented. Participants were asked to rate the pain intensity felt by Chinese/Western models of ingroup/outgroup members. Their implicit racial bias were also measured. Two lines of evidence indicated that the anterior cingulate cortex (ACC) was modulated by racial bias: (1) Chinese models elicited stronger activity than Western did in the ACC, and (2) activity in the ACC was modulated by implicit racial bias. Whereas the right anterior insula (rAI) were modulated by ingroup bias, in which ingroup member elicited stronger activity than outgroup member did. Furthermore, activity in the ACC was modulated by activity of rAI (i.e., ingroup bias) in the pain condition, while activity in the rAI was modulated by activity of ACC (i.e., racial bias) in the nopain condition. Our results provide evidence that there are different neural correlates for racial bias and ingroup bias, and neural racial bias for pain can be modulated by minimal group. PMID:29379429

Racial Bias in Neural Response for Pain Is Modulated by Minimal Group.

PubMed

Shen, Fengtao; Hu, Yang; Fan, Mingxia; Wang, Huimin; Wang, Zhaoxin

2017-01-01

Whether empathic racial bias could be modulated is a subject of intense interest. The present study was carried out to explore whether empathic racial bias for pain is modulated by minimal group. Chinese/Western faces with neutral expressions receiving painful (needle penetration) or non-painful (Q-tip touch) stimulation were presented. Participants were asked to rate the pain intensity felt by Chinese/Western models of ingroup/outgroup members. Their implicit racial bias were also measured. Two lines of evidence indicated that the anterior cingulate cortex (ACC) was modulated by racial bias: (1) Chinese models elicited stronger activity than Western did in the ACC, and (2) activity in the ACC was modulated by implicit racial bias. Whereas the right anterior insula (rAI) were modulated by ingroup bias, in which ingroup member elicited stronger activity than outgroup member did. Furthermore, activity in the ACC was modulated by activity of rAI (i.e., ingroup bias) in the pain condition, while activity in the rAI was modulated by activity of ACC (i.e., racial bias) in the nopain condition. Our results provide evidence that there are different neural correlates for racial bias and ingroup bias, and neural racial bias for pain can be modulated by minimal group.

Conditioned pain modulation: a predictor for development and treatment of neuropathic pain.

PubMed

Granovsky, Yelena

2013-09-01

Psychophysical evaluation of endogenous pain inhibition via conditioned pain modulation (CPM) represents a new generation of laboratory tests for pain assessment. In this review we discuss recent findings on CPM in neuropathic pain and refer to psychophysical, neurophysiological, and methodological aspects of its clinical implications. Typically, chronic neuropathic pain patients express less efficient CPM, to the extent that incidence of acquiring neuropathic pain (e.g. post-surgery) and its intensity can be predicted by a pre-surgery CPM assessment. Moreover, pre-treatment CPM evaluation may assist in the correct choice of serotonin-noradrenalin reuptake inhibitor analgesic agents for individual patients. Evaluation of pain modulation capabilities can serve as a step forward in individualizing pain medicine.

A single subcutaneous dose of tramadol for mild to moderate musculoskeletal trauma in the emergency department

PubMed Central

Cardozo, Alejandro; Silva, Carlos; Dominguez, Luis; Botero, Beatriz; Zambrano, Paulo; Bareno, Jose

2014-01-01

BACKGROUND: Mild to moderate musculoskeletal trauma is a common cause for an emergency room visit, and frequent pain is one of the cardinal symptoms of consultation. The objective of this study is to assess the perception of a single subcutaneous dose of 50 mg tramadol for pain management in patients with mild to moderate musculoskeletal trauma, likewise to appraise the perception of pain by subcutaneous injection. METHODS: A total of 77 patients, who met inclusion criteria, received a single subcutaneous dose of tramadol. Pain control was evaluated based on the verbal numerical pain scale (0–10) at baseline, 20 and 60 minutes; similarly, pain perception was evaluated secondary to subcutaneous injection of the analgesic. RESULTS: On admission, the average pain perceived by patients was 8; twenty minutes later, 89% of the patients reported five or less, and after sixty minutes, 94% had three or less on the verbal numerical pain scale. Of the patients, 88% reported pain perception by verbal numeric scale of 3 or less by injection of the drug, and 6.5% required a second analgesic for pain control. Two events with drug administration (soft tissue infection and mild abdominal rectus injection) were reported. CONCLUSION: We conclude that a single subcutaneous dose of tramadol is a safe and effective option for the management of patients with mild to moderate pain and musculoskeletal disease in the emergency department. PMID:25548601

Teaching Pain Management in Interprofessional Medical Education: A Review of Three Portal of Geriatric Online Education Modules.

PubMed

Madaus, Stacy M; Lim, Lionel S

2016-10-01

Chronic pain is an international healthcare crisis that affects an estimated 1.5 billion individuals worldwide, but pain management is not emphasized in the medical school curriculum, and thus supplemental education is essential. The Portal of Geriatric Online Education (POGOe) is a free repository of teaching modules for use by geriatric educators and learners. This article highlights three teaching modules available on this site: It's My Old Back Again: An Approach to Diagnosing and Managing Back Pain in the Older Adult (POGOe ID: 21670), Computer Based Learning Workbook, Third Edition module on Pain Management (POGOe ID: 21036), and Aging Q3 Curriculum on Pain Management of Older Adult Patients (POGOe ID: 21187). These modules were chosen based on their ability to address the major topics that the International Association for the Study of Pain proposes should be included in medical school curricula: mulitdimensional nature of pain, pain assessment and measurement, management of pain, and clinical conditions resulting in pain in older adults. They were also selected for their ability to be adapted for interprofessional education and how well they integrate basic science and clinical principles. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Preprocedural Anxiety and Pain Perception Following Root Surface Debridement in Chronic Periodontitis Patients.

PubMed

Naik, Vanaja Krishna; Balasundaram, Aruna; Appukuttan, Devapriya; Nainar, Deepavalli Arumuga; Milward, Michael Robert; Victor, Dhayanand John; Junaid, Mohammed

2018-01-01

The aim of this study was to evaluate and compare preprocedural dental anxiety levels and postprocedural pain perception in chronic periodontitis patients during conventional-staged root surface debridement (RSD) and single-stage RSD. Thirty-seven adult generalized chronic periodontitis patients requiring RSD were recruited in this study. Preprocedural anxiety levels were assessed using a self-reported questionnaire and postprocedural pain perceptions were assessed using 0-10 cm visual analog scale. The subject population was divided into two groups: staged RSD ( n = 18) and single-stage RSD ( n = 19). Staged RSD patients visited four times as opposed to single-stage RSD patients. Data were subjected to Pearson Chi-square test, Mann-Whitney U-test, and Spearman's rank correlation. There was no statistically significant difference in dental anxiety levels or pain perceptions in both the groups. Within Group 1, there was statistical significant difference in dental anxiety levels between visit 4 and visit 3 ( P = 0.037) and pain perception between visit 3 and visit 1 ( P = 0.005), visit 4 and visit 1 ( P = 0.002), and visit 4 and visit 2 (0.04) was statistically significant. There was a positive correlation of anxiety questionnaire (Q1-Q4) to the pain score in Group 1 which was statistically significant and in single-stage RSD. Conventional quadrant-wise RSD tends to cognitively condition the anxiety experience thus influencing pain experience.

Illness perception is significantly determined by depression and anxiety in systemic lupus erythematosus.

PubMed

Nowicka-Sauer, K; Hajduk, A; Kujawska-Danecka, H; Banaszkiewicz, D; Smoleńska, Ż; Czuszyńska, Z; Siebert, J

2018-03-01

Objectives Illness perception is a cognitive representation influencing physical and psychological functioning and adherence in patients with rheumatic disease. Studies exploring illness perception in systemic lupus erythematosus (SLE) are still scarce and none of them have investigated factors determining illness perception. We aimed to assess illness perception and to identify psychological, clinical and sociodemographic factors that might influence illness perception in SLE. Methods The study involved 80 patients with SLE (87.5% women, mean age 41.56 years). The Brief Illness Perception Questionnaire, State Trait Anxiety Inventory, Beck Depression Inventory, Pittsburgh Sleep Quality Index, Visual Analogue Scale-Pain and Fatigue Severity Scale were used. Clinical and sociodemographic data were collected via structured interview and medical files review. Results Illness perception was significantly positively correlated with anxiety, depression, sleep quality, fatigue and pain while it was not related to age, education, steroid treatment, disease duration and activity (SLEDAI) or organ damage (SLICC/ACR). Regression analysis revealed that state anxiety and depression explained 43% of illness perception variance. Cluster analysis identified three patient groups among which the middle-aged group had the most negative illness perception, the highest levels of anxiety, depression, pain and fatigue, and the poorest sleep quality. Conclusions The study has proved a significant relationship between negative illness perception and anxiety and depression. Patients reporting fatigue, poor sleep and pain might have special needs in terms of psychological intervention focused on negative illness perception and distress symptoms. Multidisciplinary care in managing SLE seems to be of great importance.

Pain patients' experiences of validation and invalidation from physicians before and after multimodal pain rehabilitation: Associations with pain, negative affectivity, and treatment outcome.

PubMed

Edlund, Sara M; Wurm, Matilda; Holländare, Fredrik; Linton, Steven J; Fruzzetti, Alan E; Tillfors, Maria

2017-10-01

Validating and invalidating responses play an important role in communication with pain patients, for example regarding emotion regulation and adherence to treatment. However, it is unclear how patients' perceptions of validation and invalidation relate to patient characteristics and treatment outcome. The aim of this study was to investigate the occurrence of subgroups based on pain patients' perceptions of validation and invalidation from their physicians. The stability of these perceptions and differences between subgroups regarding pain, pain interference, negative affectivity and treatment outcome were also explored. A total of 108 pain patients answered questionnaires regarding perceived validation and invalidation, pain severity, pain interference, and negative affectivity before and after pain rehabilitation treatment. Two cluster analyses using perceived validation and invalidation were performed, one on pre-scores and one on post-scores. The stability of patient perceptions from pre- to post-treatment was investigated, and clusters were compared on pain severity, pain interference, and negative affectivity. Finally, the connection between perceived validation and invalidation and treatment outcome was explored. Three clusters emerged both before and after treatment: (1) low validation and heightened invalidation, (2) moderate validation and invalidation, and (3) high validation and low invalidation. Perceptions of validation and invalidation were generally stable over time, although there were individuals whose perceptions changed. When compared to the other two clusters, the low validation/heightened invalidation cluster displayed significantly higher levels of pain interference and negative affectivity post-treatment but not pre-treatment. The whole sample significantly improved on pain interference and depression, but treatment outcome was independent of cluster. Unexpectedly, differences between clusters on pain interference and negative affectivity were only found post-treatment. This appeared to be due to the pre- and post-heightened invalidation clusters not containing the same individuals. Therefore, additional analyses were conducted to investigate the individuals who changed clusters. Results showed that patients scoring high on negative affectivity ended up in the heightened invalidation cluster post-treatment. Taken together, most patients felt understood when communicating with their rehabilitation physician. However, a smaller group of patients experienced the opposite: low levels of validation and heightened levels of invalidation. This group stood out as more problematic, reporting greater pain interference and negative affectivity when compared to the other groups after treatment. Patient perceptions were typically stable over time, but some individuals changed cluster, and these movements seemed to be related to negative affectivity and pain interference. These results do not support a connection between perceived validation and invalidation from physicians (meeting the patients pre- and post-treatment) and treatment outcome. Overall, our results suggest that there is a connection between negative affectivity and pain interference in the patients, and perceived validation and invalidation from the physicians. In clinical practice, it is important to pay attention to comorbid psychological problems and level of pain interference, since these factors may negatively influence effective communication. A focus on decreasing invalidating responses and/or increasing validating responses might be particularly important for patients with high levels of psychological problems and pain interference. Copyright © 2017. Published by Elsevier B.V.

Subthalamic deep brain stimulation modulates conscious perception of sensory function in Parkinson's disease.

PubMed

Cury, Rubens G; Galhardoni, Ricardo; Teixeira, Manoel J; Dos Santos Ghilardi, Maria G; Silva, Valquiria; Myczkowski, Martin L; Marcolin, Marco A; Barbosa, Egberto R; Fonoff, Erich T; Ciampi de Andrade, Daniel

2016-12-01

Subthalamic deep brain stimulation (STN-DBS) is used to treat refractory motor complications in Parkinson disease (PD), but its effects on nonmotor symptoms remain uncertain. Up to 80% of patients with PD may have pain relief after STN-DBS, but it is unknown whether its analgesic properties are related to potential effects on sensory thresholds or secondary to motor improvement. We have previously reported significant and long-lasting pain relief after DBS, which did not correlate with motor symptomatic control. Here we present secondary data exploring the effects of DBS on sensory thresholds in a controlled way and have explored the relationship between these changes and clinical pain and motor improvement after surgery. Thirty-seven patients were prospectively evaluated before STN-DBS and 12 months after the procedure compared with healthy controls. Compared with baseline, patients with PD showed lower thermal and mechanical detection and higher cold pain thresholds after surgery. There were no changes in heat and mechanical pain thresholds. Compared with baseline values in healthy controls, patients with PD had higher thermal and mechanical detection thresholds, which decreased after surgery toward normalization. These sensory changes had no correlation with motor or clinical pain improvement after surgery. These data confirm the existence of sensory abnormalities in PD and suggest that STN-DBS mainly influenced the detection thresholds rather than painful sensations. However, these changes may depend on the specific effects of DBS on somatosensory loops with no correlation to motor or clinical pain improvement.

Changes of spontaneous oscillatory activity to tonic heat pain.

PubMed

Peng, Weiwei; Hu, Li; Zhang, Zhiguo; Hu, Yong

2014-01-01

Transient painful stimuli could induce suppression of alpha oscillatory activities and enhancement of gamma oscillatory activities that also could be greatly modulated by attention. Here, we attempted to characterize changes in cortical activities during tonic heat pain perception and investigated the influence of directed/distracted attention on these responses. We collected 5-minute long continuous Electroencephalography (EEG) data from 38 healthy volunteers during four conditions presented in a counterbalanced order: (A) resting condition; (B) innoxious-distracted condition; (C) noxious-distracted condition; (D) noxious-attended condition. The effects of tonic heat pain stimulation and selective attention on oscillatory activities were investigated by comparing the EEG power spectra among the four experimental conditions and assessing the relationship between spectral power difference and subjective pain intensity. The change of oscillatory activities in condition D was characterized by stable and persistent decrease of alpha oscillation power over contralateral-central electrodes and widespread increase of gamma oscillation power, which were even significantly correlated with subjective pain intensity. Since EEG responses in the alpha and gamma frequency band were affected by attention in different manners, they are likely related to different aspects of the multidimensional sensory experience of pain. The observed contralateral-central alpha suppression (conditions D vs. B and D vs. C) may reflect primarily a top-down cognitive process such as attention, while the widespread gamma enhancement (conditions D vs. A) may partly reflect tonic pain processing, representing the summary effects of bottom-up stimulus-related and top-down subject-driven cognitive processes.

Changes of Spontaneous Oscillatory Activity to Tonic Heat Pain

PubMed Central

Zhang, Zhiguo; Hu, Yong

2014-01-01

Transient painful stimuli could induce suppression of alpha oscillatory activities and enhancement of gamma oscillatory activities that also could be greatly modulated by attention. Here, we attempted to characterize changes in cortical activities during tonic heat pain perception and investigated the influence of directed/distracted attention on these responses. We collected 5-minute long continuous Electroencephalography (EEG) data from 38 healthy volunteers during four conditions presented in a counterbalanced order: (A) resting condition; (B) innoxious-distracted condition; (C) noxious-distracted condition; (D) noxious-attended condition. The effects of tonic heat pain stimulation and selective attention on oscillatory activities were investigated by comparing the EEG power spectra among the four experimental conditions and assessing the relationship between spectral power difference and subjective pain intensity. The change of oscillatory activities in condition D was characterized by stable and persistent decrease of alpha oscillation power over contralateral-central electrodes and widespread increase of gamma oscillation power, which were even significantly correlated with subjective pain intensity. Since EEG responses in the alpha and gamma frequency band were affected by attention in different manners, they are likely related to different aspects of the multidimensional sensory experience of pain. The observed contralateral-central alpha suppression (conditions D vs. B and D vs. C) may reflect primarily a top-down cognitive process such as attention, while the widespread gamma enhancement (conditions D vs. A) may partly reflect tonic pain processing, representing the summary effects of bottom-up stimulus-related and top-down subject-driven cognitive processes. PMID:24603703

Written pain neuroscience education in fibromyalgia: a multicenter randomized controlled trial.

PubMed

van Ittersum, Miriam W; van Wilgen, C Paul; van der Schans, Cees P; Lambrecht, Luc; Groothoff, Johan W; Nijs, Jo

2014-11-01

Mounting evidence supports the use of face-to-face pain neuroscience education for the treatment of chronic pain patients. This study aimed at examining whether written education about pain neuroscience improves illness perceptions, catastrophizing, and health status in patients with fibromyalgia. A double-blind, multicenter randomized controlled clinical trial with 6-month follow-up was conducted. Patients with FM (n = 114) that consented to participate were randomly allocated to receive either written pain neuroscience education or written relaxation training. Written pain neuroscience education comprised of a booklet with pain neuroscience education plus a telephone call to clarify any difficulties; the relaxation group received a booklet with relaxation education and a telephone call. The revised illness perception questionnaire, Pain Catastrophizing Scale, and fibromyalgia impact questionnaire were used as outcome measures. Both patients and assessors were blinded. Repeated-measures analyses with last observation carried forward principle were performed. Cohen's d effect sizes (ES) were calculated for all within-group changes and between-group differences. The results reveal that written pain neuroscience education does not change the impact of FM on daily life, catastrophizing, or perceived symptoms of patients with FM. Compared with written relaxation training, written pain neuroscience education improved beliefs in a chronic timeline of FM (P = 0.03; ES = 0.50), but it does not impact upon other domains of illness perceptions. Compared with written relaxation training, written pain neuroscience education slightly improved illness perceptions of patients with FM, but it did not impart clinically meaningful effects on pain, catastrophizing, or the impact of FM on daily life. Face-to-face sessions of pain neuroscience education are required to change inappropriate cognitions and perceived health in patients with FM. © 2013 World Institute of Pain.

Transcutaneous Electrical Nerve Stimulation and Conditioned Pain Modulation Influence the Perception of Pain in Humans

PubMed Central

Liebano, Richard E.; Vance, Carol G.T.; Rakel, Barbara; Lee, Jennifer E.; Cooper, Nicholas A.; Marchand, Serge; Walsh, Deirdre M.; Sluka, Kathleen A.

2013-01-01

Background Research in animal models suggest that transcutaneous electrical nerve stimulation (TENS) and conditioned pain modulation (CPM) produce analgesia via two different supraspinal pathways. No known studies have examined whether TENS and CPM applied simultaneously in human subjects will enhance the analgesic effect of either treatment alone. The purpose of the current study was to investigate whether the simultaneous application of TENS and CPM will enhance the analgesic effect of that produced by either treatment alone. Methods Sixty healthy adults were randomly allocated into 2 groups: 1) CPM plus Active TENS; 2) CPM plus Placebo TENS. Pain threshold for heat (HPT) and pressure (PPT) was recorded from subject’s left forearm at baseline, during CPM, during Active or Placebo TENS, and during CPM plus Active or Placebo TENS. CPM was induced by placing the subjects’ contralateral arm in a hot water bath (46.5°C) for two minutes. TENS (100µs, 100Hz) was applied to the forearm for 20 minutes at a strong but comfortable intensity. Results Active TENS alone increased PPT (but not HPT) more than Placebo TENS alone (p=0.011). Combining CPM and Active TENS did not significantly increase PPT (p=0.232) or HPT (p=0.423) beyond CPM plus Placebo TENS. There was a significant positive association between PPT during CPM and during Active TENS (r2=0.46, p=0.003). Conclusions TENS application increases PPT, however combining CPM and TENS does not increase the CPM’s hypoalgesic response. CPM effect on PPT is associated with effects of TENS on PPT. PMID:23650092

Impact of pictorial story on pain perception, situational anxiety and behavior in children: a cognitive-behavioral schema.

PubMed

Aminabadi, N A; Vafaei, A; Erfanparast, L; Oskouei, S G; Jamali, Z

2011-01-01

The present study evaluated the effect of listening to a pictorial story about going to the dentist on pain perception, situational anxiety and behavioral feedback during dental treatment in pediatric dental patients. Eighty, 6-7-year-old children were included The childhood anxiety-related disorders using Screen for Child Anxiety Related Disorders (SCARED) Parent Version scale and intelligence quotient using Raven's Progressive Matrices were evaluated The subjects were randomly assigned to two groups, listening to a pictorial story about going to a dentist (test), or listening to a pictorial story about going to a barbershop (control). A dental treatment was performed on each subject, during which, behavior was assessed using Sound, Eye, and Motor Scale. Pain perception and situational anxiety were then assessed using Wong-Baker Fasces Pain Rating Scale and Faces version of the Modified Child Dental Anxiety Scale, respectively. There was a significant decrease in pain perception (P=0.02) and situational anxiety (P<0.001) in the test group. In addition, the test intervention significantly improved children behavioral feedback during dental treatment (P<0.001). Preparation of children with pictorial story can be effective in decreasing pain perception and situational anxiety as well as improving behavior during dental treatment.

Impaired insula functional connectivity associated with persistent pain perception in patients with complex regional pain syndrome

PubMed Central

Jang, Joon Hwan; Lee, Do-Hyeong; Lee, Kyung-Jun; Lee, Won Joon; Moon, Jee Youn; Kim, Yong Chul

2017-01-01

Given that the insula plays a contributory role in the perception of chronic pain, we examined the resting-state functional connectivity between the insular cortex and other brain regions to investigate neural underpinnings of persisting perception of background pain in patients with complex regional pain syndrome (CRPS). A total of 25 patients with CRPS and 25 matched healthy controls underwent functional magnetic resonance imaging at rest. With the anterior and posterior insular cortices as seed regions, we compared the strength of the resting-state functional connectivity between the two groups. Functional connectivity between the anterior and posterior insular cortices and the postcentral and inferior frontal gyri, cingulate cortices was reduced in patients with CRPS compared with controls. Additionally, greater reductions in functional connectivity between the anterior insula and right postcentral gyrus were associated with more severe sensory pain in patients with CRPS (short-form McGill Pain Questionnaire sensory subscores, r = -.517, P = .023). The present results imply a possible role of the insula in aberrant processing of pain information in patients with CRPS. The findings suggest that a functional derangement of the connection between one of the somatosensory cortical functions of perception and one of the insular functions of awareness can play a significant role in the persistent experience of regional pain that is not confined to a specific nerve territory. PMID:28692702

Endogenous pain modulation in chronic orofacial pain: a systematic review and meta-analysis.

PubMed

Moana-Filho, Estephan J; Herrero Babiloni, Alberto; Theis-Mahon, Nicole R

2018-06-15

Abnormal endogenous pain modulation was suggested as a potential mechanism for chronic pain, ie, increased pain facilitation and/or impaired pain inhibition underlying symptoms manifestation. Endogenous pain modulation function can be tested using psychophysical methods such as temporal summation of pain (TSP) and conditioned pain modulation (CPM), which assess pain facilitation and inhibition, respectively. Several studies have investigated endogenous pain modulation function in patients with nonparoxysmal orofacial pain (OFP) and reported mixed results. This study aimed to provide, through a qualitative and quantitative synthesis of the available literature, overall estimates for TSP/CPM responses in patients with OFP relative to controls. MEDLINE, Embase, and the Cochrane databases were searched, and references were screened independently by 2 raters. Twenty-six studies were included for qualitative review, and 22 studies were included for meta-analysis. Traditional meta-analysis and robust variance estimation were used to synthesize overall estimates for standardized mean difference. The overall standardized estimate for TSP was 0.30 (95% confidence interval: 0.11-0.49; P = 0.002), with moderate between-study heterogeneity (Q [df = 17] = 41.8, P = 0.001; I = 70.2%). Conditioned pain modulation's estimated overall effect size was large but above the significance threshold (estimate = 1.36; 95% confidence interval: -0.09 to 2.81; P = 0.066), with very large heterogeneity (Q [df = 8] = 108.3, P < 0.001; I = 98.0%). Sensitivity analyses did not affect the overall estimate for TSP; for CPM, the overall estimate became significant if specific random-effect models were used or if the most influential study was removed. Publication bias was not present for TSP studies, whereas it substantially influenced CPM's overall estimate. These results suggest increased pain facilitation and trend for pain inhibition impairment in patients with nonparoxysmal OFP.

When in doubt, ask the audience: potential users' perceptions of Internet-delivered cognitive behavioural therapy for chronic pain.

PubMed

Schneider, Luke H; Hadjistavropoulos, Heather D

2014-01-01

Although research has demonstrated that Internet-delivered cognitive behavioural therapy (ICBT) for chronic pain helps with adjustment to pain, it remains unclear how this treatment option would initially be perceived by individuals with chronic pain. To explore initial perceptions of ICBT and to examine variables that correlate with an expressed interest in ICBT as a treatment option among individuals with chronic pain. A total of 129 individuals with chronic pain completed a survey assessing perceptions of ICBT and individual difference variables that could be correlated with expressed interest in ICBT (eg, demographic characteristics, pain, computer self-efficacy). Results showed that most participants perceived ICBT as a potentially valuable service with multiple benefits. Being female, having greater pain severity and interference, and having greater computer self-efficacy and lower computer anxiety were positively correlated with interest in receiving ICBT. Combined with previous research on treatment efficacy of ICBT for chronic pain, the results should serve to stimulate further research on integrating ICBT within existing health care services.

The effect of social stress on chronic pain perception in female and male mice.

PubMed

Aghajani, Marjan; Vaez Mahdavi, Mohammad Reza; Khalili Najafabadi, Mohsen; Ghazanfari, Tooba

2012-01-01

The current investigations on social stress primarily point to the negative health consequences of being in a stressful social hierarchy. The repetitive nature of such stressors seems to affect behavioral response to pain both in rodents and humans. Moreover, a large discrepancy in the possibility of social stresses affecting pain perception in the two genders exists. The present study examined the effect of chronic social stress on nociceptive responses of both sexes by implementing of food deprivation, food intake inequality and unstable social status (cage-mate change every 3 days) for a period of 14 days in 96 Balb/c mice. In this regard we injected 20 µl formalin 2% into the plantar surface of hind paw at the end of stress period and scored pain behaviors of all subjects, then serum concentrations of proinflammatory cytokines were measured. Our results showed that there was significant difference in chronic phase of formalin test following implementation of food deprivation and inequality (P<0.05) as compared to control group, so that pain perception was decreased considerably and this decline in inequality exposed subjects was well above isolated ones (P<0.05); whereas unstable social situation did not affect pain perception. Moreover, IL-1 and IL-6 concentrations in serum of stressed mice of both genders were well above control group (p<0.05). Finally, despite chronic pain perception in control and unstable male subjects was larger than females; the decrease of chronic pain perception in male stressed animals (poverty and inequality experienced subjects) was much more than stressed females. These results revealed that although food deprivation and social inequality can induce hypoalgesia, some socioeconomic situations like social instability don't affect pain sensation, whereas there were similar increases of proinflammatory cytokines level in all socially stressed subjects. In addition, males display larger hypoalgesic responses to inequality as compared with females.

Personalized Pain Medicine: The Clinical Value of Psychophysical Assessment of Pain Modulation Profile

PubMed Central

Granovsky, Yelena; Yarnitsky, David

2013-01-01

Experimental pain stimuli can be used to simulate patients’ pain experience. We review recent developments in psychophysical pain testing, focusing on the application of the dynamic tests—conditioned pain modulation (CPM) and temporal summation (TS). Typically, patients with clinical pain of various types express either less efficient CPM or enhanced TS, or both. These tests can be used in prediction of incidence of acquiring pain and of its intensity, as well as in assisting the correct choice of analgesic agents for individual patients. This can help to shorten the commonly occurring long and frustrating process of adjusting analgesic agents to the individual patients. We propose that evaluating pain modulation can serve as a step forward in individualizing pain medicine. PMID:24228167

Personalized pain medicine: the clinical value of psychophysical assessment of pain modulation profile.

PubMed

Granovsky, Yelena; Yarnitsky, David

2013-01-01

Experimental pain stimuli can be used to simulate patients' pain experience. We review recent developments in psychophysical pain testing, focusing on the application of the dynamic tests-conditioned pain modulation (CPM) and temporal summation (TS). Typically, patients with clinical pain of various types express either less efficient CPM or enhanced TS, or both. These tests can be used in prediction of incidence of acquiring pain and of its intensity, as well as in assisting the correct choice of analgesic agents for individual patients. This can help to shorten the commonly occurring long and frustrating process of adjusting analgesic agents to the individual patients. We propose that evaluating pain modulation can serve as a step forward in individualizing pain medicine.

Efficient conditioned pain modulation despite pain persistence in painful diabetic neuropathy.

PubMed

Granovsky, Yelena; Nahman-Averbuch, Hadas; Khamaisi, Mogher; Granot, Michal

2017-05-01

Alleviation of pain, by either medical or surgical therapy, is accompanied by transition from less efficient, or pro-nociceptive, to efficient conditioned pain modulation (CPM). Spontaneous decrease or resolution of pain with disease progression is reported for some patients with painful diabetic neuropathy (PDN). To explore whether CPM changes similarly in parallel to spontaneous resolution of pain in PDN patients. In this cross-sectional study, thirty-three patients with PDN underwent psychophysical assessment of pain modulation on the forearm, remote from the clinical pain. Pain duration was not correlated with neuropathic pain intensity, yet, it correlated with CPM efficiency; patients with longer pain duration had same pain level, but more efficient CPM than those with short-pain duration (ρ = -0.417; P = 0.025, Spearman correlation). Patients with pain more than 2 years (median split) expressed efficient CPM that was not different from that of healthy controls. These patients also had lower temporal summation of pain than the short-pain duration patients group ( P < 0.05). The 2 patient groups did not differ in clinical pain characteristics or use of analgesics. Pro-nociception, expressed by less efficient CPM and high temporal summation that usually accompanies clinical painful conditions, seems to "normalize" with chronicity of the pain syndrome. This is despite continuing pain, suggesting that pro-nociceptivity in pain syndromes is multifactorial. Because the pain modulation profile affects success of therapy, this suggests that different drugs might express different efficacy pending on duration of the pain in patients with PDN.

Stress and visceral pain: from animal models to clinical therapies

PubMed Central

Larauche, Muriel; Mulak, Agata; Taché, Yvette

2011-01-01

Epidemiological studies have implicated stress (psychosocial and physical) as a trigger of first onset or exacerbation of irritable bowel syndrome (IBS) symptoms of which visceral pain is an integrant landmark. A number of experimental acute or chronic exteroceptive or interoceptive stressors induce visceral hyperalgesia in rodents although recent evidence also points to stress-related visceral analgesia as established in the somatic pain field. Underlying mechanisms of stress-related visceral hypersensitivity may involve a combination of sensitization of primary afferents, central sensitization in response to input from the viscera and dysregulation of descending pathways that modulate spinal nociceptive transmission or analgesic response. Biochemical coding of stress involves the recruitment of corticotropin releasing factor (CRF) signaling pathways. Experimental studies established that activation of brain and peripheral CRF receptor subtype 1 plays a primary role in the development of stress-related delayed visceral hyperalgesia while subtype 2 activation induces analgesic response. In line with stress pathways playing a role in IBS, non-pharmacologic and pharmacologic treatment modalities aimed at reducing stress perception using a broad range of evidence-based mind-body interventions and centrally-targeted medications to reduce anxiety impact on brain patterns activated by visceral stimuli and dampen visceral pain. PMID:21575632

Pain Perception: Computerized versus Traditional Local Anesthesia in Pediatric Patients.

PubMed

Mittal, M; Kumar, A; Srivastava, D; Sharma, P; Sharma, S

2015-01-01

Local anesthetic injection is one of the most anxiety- provoking procedure for both children and adult patients in dentistry. A computerized system for slow delivery of local anesthetic has been developed as a possible solution to reduce the pain related to the local anesthetic injection. The present study was conducted to evaluate and compare pain perception rates in pediatric patients with computerized system and traditional methods, both objectively and subjectively. It was a randomized controlled study in one hundred children aged 8-12 years in healthy physical and mental state, assessed as being cooperative, requiring extraction of maxillary primary molars. Children were divided into two groups by random sampling - Group A received buccal and palatal infiltration injection using Wand, while Group B received buccal and palatal infiltration using traditional syringe. Visual Analog scale (VAS) was used for subjective evaluation of pain perception by patient. Sound, Eye, Motor (SEM) scale was used as an objective method where sound, eye and motor reactions of patient were observed and heart rate measurement using pulse oximeter was used as the physiological parameter for objective evaluation. Patients experienced significantly less pain of injection with the computerized method during palatal infiltration, while less pain was not statistically significant during buccal infiltration. Heart rate increased during both buccal and palatal infiltration in traditional and computerized local anesthesia, but difference between traditional and computerized method was not statistically significant. It was concluded that pain perception was significantly more during traditional palatal infiltration injection as compared to computerized palatal infiltration, while there was no difference in pain perception during buccal infiltration in both the groups.

Serum dehydroepiandrosterone sulphate, psychosocial factors and musculoskeletal pain in workers.

PubMed

Marinelli, A; Prodi, A; Pesel, G; Ronchese, F; Bovenzi, M; Negro, C; Larese Filon, F

2017-12-30

The serum level of dehydroepiandrosterone sulphate (DHEA-S) has been suggested as a biological marker of stress. To assess the association between serum DHEA-S, psychosocial factors and musculoskeletal (MS) pain in university workers. The study population included voluntary workers at the scientific departments of the University of Trieste (Italy) who underwent periodical health surveillance from January 2011 to June 2012. DHEA-S level was analysed in serum. The assessment tools included the General Health Questionnaire (GHQ) and a modified Nordic musculoskeletal symptoms questionnaire. The relation between DHEA-S, individual characteristics, pain perception and psychological factors was assessed by means of multivariable linear regression analysis. There were 189 study participants. The study population was characterized by high reward and low effort. Pain perception in the neck, shoulder, upper limbs, upper back and lower back was reported by 42, 32, 19, 29 and 43% of people, respectively. In multivariable regression analysis, gender, age and pain perception in the shoulder and upper limbs were significantly related to serum DHEA-S. Effort and overcommitment were related to shoulder and neck pain but not to DHEA-S. The GHQ score was associated with pain perception in different body sites and inversely to DHEA-S but significance was lost in multivariable regression analysis. DHEA-S was associated with age, gender and perception of MS pain, while effort-reward imbalance dimensions and GHQ score failed to reach the statistical significance in multivariable regression analysis. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Pain as the Perception of Someone: An Analysis of the Interface Between Pain Medicine and Philosophy.

PubMed

Bäckryd, Emmanuel

2018-06-23

Based largely on the so-called problem of "asymmetry in concept application", philosopher Murat Aydede has argued for a non-perceptual view of pain. Aydede is of course not denying basic neurobiological facts about neurons, action potentials, and the like, but he nonetheless makes a strong philosophical case for pain not being the perception of something extramental. In the present paper, after having stated some of the presuppositions I hold as a physician and pain researcher, and after having shortly described Aydede's critique of perceptual theories of pain, I make a constructive proposal centred around the concept of pain as the perception of some-one, not some-thing. In doing so, I propose that there often is a problematic duality at work when we think about pain, namely the mental/extramental duality. This pre-reflective mindset creates difficulties when reflecting over pain. Instead, I propose the body/world duality as being more helpful. Two neologisms, cosmoception and egoception, are presented as an alternative to the twin concepts of exteroception and interoception. It is argued that the new concepts have the advantage of not pushing our thought into a mental/extra-mental dichotomy. Hence, when in pain (which is an instance of egoception), I get epistemic access to the body that is I, to how I fare in this world. From that perspective, pain is not the perception of something, but of someone-namely, the self. In the final part of the paper, this proposal is discussed in dialogue with a paper from phenomenological thinker Jennifer Bullington.

Single-trial laser-evoked potentials feature extraction for prediction of pain perception.

PubMed

Huang, Gan; Xiao, Ping; Hu, Li; Hung, Yeung Sam; Zhang, Zhiguo

2013-01-01

Pain is a highly subjective experience, and the availability of an objective assessment of pain perception would be of great importance for both basic and clinical applications. The objective of the present study is to develop a novel approach to extract pain-related features from single-trial laser-evoked potentials (LEPs) for classification of pain perception. The single-trial LEP feature extraction approach combines a spatial filtering using common spatial pattern (CSP) and a multiple linear regression (MLR). The CSP method is effective in separating laser-evoked EEG response from ongoing EEG activity, while MLR is capable of automatically estimating the amplitudes and latencies of N2 and P2 from single-trial LEP waveforms. The extracted single-trial LEP features are used in a Naïve Bayes classifier to classify different levels of pain perceived by the subjects. The experimental results show that the proposed single-trial LEP feature extraction approach can effectively extract pain-related LEP features for achieving high classification accuracy.

Pain modality- and sex-specific effects of COMT genetic functional variants

PubMed Central

Belfer, Inna; Segall, Samantha K.; Lariviere, William R.; Smith, Shad B.; Dai, Feng; Slade, Gary G.; Rashid, Naim U.; Mogil, Jeffrey S.; Campbell, Claudia; Edwards, Robert; Liu, Qian; Bair, Eric; Maixner, William; Diatchenko, Luda

2013-01-01

The enzyme catechol-O-methyltransferase (COMT) metabolizes catecholamine neurotransmitters involved in a number of physiological functions including pain perception. Both human and mouse COMT genes possess functional polymorphisms contributing to inter-individual variability in pain phenotypes such as sensitivity to noxious stimuli, severity of clinical pain and response to pain treatment. In this study, we found that the effects of Comt functional variation in mice are modality-specific. Spontaneous inflammatory nociception and thermal nociception behaviors were correlated the most with the presence of the B2 SINE transposon insertion residing in the 3’UTR mRNA region. Similarly, in humans, COMT functional haplotypes were associated with thermal pain perception and with capsaicin-induced pain. Furthermore, COMT genetic variations contributed to pain behaviors in mice and pain ratings in humans in a sex-specific manner. The ancestral Comt variant, without a B2 SINE insertion, was more strongly associated with sensitivity to capsaicin in female versus male mice. In humans, the haplotype coding for low COMT activity increased capsaicin-induced pain perception in women, but not men. These findings reemphasize the fundamental contribution of COMT to pain processes, and provide a fine-grained resolution of this contribution at the genetic level that can be used to guide future studies in the area of pain genetics. PMID:23701723

Do anxiety, stress, or depression have any impact on pain perception during shock wave lithotripsy?

PubMed

Altok, Muammer; Akpinar, Abdullah; Güneş, Mustafa; Umul, Mehmet; Demirci, Kadir; Baş, Ercan

2016-01-01

The most important adverse effect during shock wave lithotripsy (SWL) is pain perception. In this study, we evaluated the effect of anxiety, stress, and depression on pain perception during SWL. From November 2013 to December 2014, 189 consecutive patients undergoing SWL for kidney stones were evaluated prospectively. Patient characteristics (age, sex, body mass index [BMI], urologic intervention history, the presence of a double-j catheter, and stone-related parameters) were also recorded. Anxiety, stress, and depression states were assessed before the first procedure using the Depression, Anxiety, and Stress Scales (DASS-42), which is a self-report scale. The degree of pain perception was evaluated with a 10-point Visual Analogue Scale (VAS) at the end of the first SWL session. There were no statistically significant differences in terms of VAS scores during SWL between patients with and without anxiety, stress, or depression (p >0.05). Furthermore, no statistically significant relationships were found between VAS scores and patient age, sex, side of the stone, presence of a double-j stent, number of stones, and SWL experience (p >0.05). According to our findings, anxiety, stress, or depression seemed to have no impact on pain perception during SWL.

Controllability and hippocampal activation during pain expectation in fibromyalgia syndrome.

PubMed

González-Roldán, Ana María; Bomba, Isabelle C; Diesch, Eugen; Montoya, Pedro; Flor, Herta; Kamping, Sandra

2016-12-01

To examine the role of perceived control in pain perception, fibromyalgia patients and healthy controls participated in a reaction time experiment under different conditions of pain controllability. No significant differences between groups were found in pain intensity and unpleasantness ratings. However, during the expectation of uncontrollable pain, patients compared to controls showed higher hippocampal activation. In addition, hippocampal activity during the pain expectation period predicted activation of the posterior cingulate cortex (PCC), precuneus and hippocampus during pain stimulation in fibromyalgia patients. The increased activation of the hippocampus during pain expectation and subsequent activation of the PCC/precuneus during the lack of control phase points towards an influence of pain perception through heightening of alertness and anxiety responses to pain in fibromyalgia patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Pronociceptive pain modulation in patients with painful chemotherapy-induced polyneuropathy.

PubMed

Nahman-Averbuch, Hadas; Yarnitsky, David; Granovsky, Yelena; Sprecher, Elliot; Steiner, Mariana; Tzuk-Shina, Tzahala; Pud, Dorit

2011-08-01

Several chemotherapy agents induce polyneuropathy that is painful for some patients, but not for others. We assumed that these differences might be attributable to varying patterns of pain modulation. The aim of the present study was to evaluate pain modulation in such patients. Twenty-seven patients with chemotherapy-induced polyneuropathy were tested for detection thresholds (cold, warm, and mechanical) in both the forearm and foot, as well as for heat pain threshold, mechanical temporal summation (TS), and conditioned pain modulation (CPM; also known as the diffuse noxious inhibitory control-like effect), which were tested in the upper limbs. Positive correlations were found between clinical pain levels and both TS (r=0.52, P=0.005) and CPM (r=0.40, P=0.050) for all patients. In addition, higher TS was associated with less efficient CPM (r=0.56, P=0.004). The group of patients with painful polyneuropathy (n=12) showed a significantly higher warm detection threshold in the foot (P=0.03), higher TS (P<0.01), and less efficient CPM (P=0.03) in comparison to the group with nonpainful polyneuropathy. The painfulness of polyneuropathy is associated with a "pronociceptive" modulation pattern, which may be primary to the development of pain. The higher warm sensory thresholds in the painful polyneuropathy group suggest that the severity of polyneuropathy may be another factor in determining its painfulness. Copyright © 2011 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.

Triathletes Lose Their Advantageous Pain Modulation under Acute Psychosocial Stress.

PubMed

Geva, Nirit; Pruessner, Jens; Defrin, Ruth

2017-02-01

Triathletes, who constantly engage in intensely stressful sport, were recently found to exhibit greater pain tolerance and more efficient pain inhibition capabilities than nonathletes. However, pain inhibition correlated negatively with retrospective reports of mental stress during training and competition. The aim of the current study was to test pain inhibition capabilities of triathletes under acute, controlled psychological stress manipulation. Participants were 25 triathletes and ironman triathletes who underwent the measurement of pain threshold, pain intolerance, tonic suprathreshold pain, and conditioned pain modulation before and during exposure to the Montreal Imaging Stress Task (MIST). Perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol levels were obtained as indices of stress. The MIST induced a significant stress reaction manifested in the subjective and objective indices. Overall, a significant reduction in pain threshold and in conditioned pain modulation efficacy was observed after the MIST, which reached the baseline levels observed previously in nonathletes. Paradoxically, the magnitude of this stress-induced hyperalgesia (SIH) correlated negatively with the magnitude of the stress response; low-stress responders exhibited greater SIH than high-stress responders. The results suggest that under acute psychological stress, triathletes not only react with SIH and a reduction in pain modulation but also lose their advantageous pain modulation over nonathletes. The stronger the stress response recorded, the weaker the SIH. It appears that triathletes are not resilient to stress, responding with an increase in the sensitivity to pain as well as a decrease in pain inhibition. The possible effects of athletes' baseline pain profile and stress reactivity on SIH are discussed.

Low-threshold mechanoreceptors play a frequency-dependent dual role in subjective ratings of mechanical allodynia.

PubMed

Löken, Line S; Duff, Eugene P; Tracey, Irene

2017-12-01

In the setting of injury, myelinated primary afferent fibers that normally signal light touch are thought to switch modality and instead signal pain. In the absence of injury, touch is perceived as more intense when firing rates of Aβ afferents increase. However, it is not known if varying the firing rates of Aβ afferents have any consequence to the perception of dynamic mechanical allodynia (DMA). We hypothesized that, in the setting of injury, the unpleasantness of DMA would be intensified as the firing rates of Aβ afferents increase. Using a stimulus-response protocol established in normal skin, where an increase in brush velocity results in an increase of Aβ afferent firing rates, we tested if brush velocity modulated the unpleasantness of capsaicin-induced DMA. We analyzed how changes in estimated low-threshold mechanoreceptor firing activity influenced perception and brain activity (functional MRI) of DMA. Brushing on normal skin was perceived as pleasant, but brushing on sensitized skin produced both painful and pleasant sensations. Surprisingly, there was an inverse relationship between Aβ firing rates and unpleasantness such that brush stimuli that produced low firing rates were most painful and those that elicited high firing rates were rated as pleasant. Concurrently to this, we found increased cortical activity in response to low Aβ firing rates in regions previously implicated in pain processing during brushing of sensitized skin, but not normal skin. We suggest that Aβ signals do not merely switch modality to signal pain during injury. Instead, they exert a high- and low-frequency-dependent dual role in the injured state, with respectively both pleasant and unpleasant consequences. NEW & NOTEWORTHY We suggest that Aβ signals do not simply switch modality to signal pain during injury but play a frequency-dependent and dual role in the injured state with both pleasant and unpleasant consequences. These results provide a framework to resolve the apparent paradox of how touch can inhibit pain, as proposed by the Gate Control Theory and the existence of dynamic mechanical allodynia.

The Use of Music in Labor: Pain Perception

DTIC Science & Technology

1991-01-01

AD-A267 985liiiiiii ii ii iii lillinl lJtlflllllIi 1\\k . Music in Labor DTIC43.t ELECTE wN AUGt 1 1993UThe Use of Music in Labor: A C1 Pain...Perception Kathy Jo Keever Patricia A. Shepherd AFIT/Georgetown University School of Nursing Running head: MUSIC IN LABOR Ap9i" "r85T16x• ~ ;u~c r~eca _W...FUNDING NUMBERS The Use of Music in Labor: Pain Perception 6. AUTHOR(S) 1st Lt Kathy Keever Capt Patricia Shepherd PERFORMING ORGANIZATION NAME(S) AND

Ethnicity and patient's perception of risk in joint replacement surgery.

PubMed

Gandhi, Rajiv; Razak, Fahad; Davey, J Roderick; Mahomed, Nizar N

2008-08-01

Despite much evidence showing racial disparities in the use of surgical procedures, it is unknown whether ethnicity affects perception of surgical risk. We surveyed 1609 patients undergoing primary hip or knee replacement surgery. Relevant covariates including demographic data, body mass index (BMI), sex, comorbidities, education, and ethnicity were recorded. Pain and joint functional status were assessed at baseline and at 1-year followup with the Western Ontario McMaster University Osteoarthritis Index (WOMAC) pain and function scores. Risk perception was assessed with 3 survey questions. Non-European patients had greater functional disability and pain prior to surgery and demonstrated significantly greater perception of risk than European patients (p < 0.001). Independent of other covariates, non-European ethnicity was an independent predictor of a greater perception of risk (p < 0.05). Patient ethnicity is an important factor to consider in understanding a patient's perception of risk in joint replacement surgery.

Conditioned pain modulation predicts duloxetine efficacy in painful diabetic neuropathy.

PubMed

Yarnitsky, David; Granot, Michal; Nahman-Averbuch, Hadas; Khamaisi, Mogher; Granovsky, Yelena

2012-06-01

This study aims to individualize the selection of drugs for neuropathic pain by examining the potential coupling of a given drug's mechanism of action with the patient's pain modulation pattern. The latter is assessed by the conditioned pain modulation (CPM) and temporal summation (TS) protocols. We hypothesized that patients with a malfunctioning pain modulation pattern, such as less efficient CPM, would benefit more from drugs augmenting descending inhibitory pain control than would patients with a normal modulation pattern of efficient CPM. Thirty patients with painful diabetic neuropathy received 1 week of placebo, 1 week of 30 mg/d duloxetine, and 4 weeks of 60 mg/d duloxetine. Pain modulation was assessed psychophysically, both before and at the end of treatment. Patient assessment of drug efficacy, assessed weekly, was the study's primary outcome. Baseline CPM was found to be correlated with duloxetine efficacy (r=0.628, P<.001, efficient CPM is marked negative), such that less efficient CPM predicted efficacious use of duloxetine. Regression analysis (R(2)=0.673; P=.012) showed that drug efficacy was predicted only by CPM (P=.001) and not by pretreatment pain levels, neuropathy severity, depression level, or patient assessment of improvement by placebo. Furthermore, beyond its predictive value, the treatment-induced improvement in CPM was correlated with drug efficacy (r=-0.411, P=.033). However, this improvement occurred only in patients with less efficient CPM (16.8±16.0 to -1.1±15.5, P<.050). No predictive role was found for TS. In conclusion, the coupling of CPM and duloxetine efficacy highlights the importance of pain pathophysiology in the clinical decision-making process. This evaluative approach promotes personalized pain therapy. Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Pain perception and low back pain functional disability after a 10-week core and mobility training program: A pilot study.

PubMed

Lima, Vicente Pinheiro; de Alkmim Moreira Nunes, Rodolfo; da Silva, Jurandir Baptista; Paz, Gabriel Andrade; Jesus, Marco; de Castro, Juliana Brandão Pinto; Dantas, Estélio Henrique Martin; de Souza Vale, Rodrigo Gomes

2018-03-02

The aim of this study was to evaluate the effects of a 10-week core and mobility training program on pain perception and low back disability score in professors, students and employees of a university. Twenty-four individuals of a university who previously reported pain and low back disability were randomly assigned to an experimental group (EG; n= 8) that received 2 weekly sessions of 50 minutes of core and mobility training for 10 weeks; or to a control group (CG; n= 16). Both groups received a guideline to adopt ergonomic postures during work and activities of daily living. The visual analog pain scale (VAS) and the Roland-Morris questionnaire (RMQ) were applied pre and post intervention. Significant reductions in the pain intensity perception (p= 0.014) and low back functional disability (p= 0.011) were noted in the EG pre and post measures. However, no significant difference was observed in the CG. Thus, there was a significant difference between the EG and the CG in the post-intervention measures (p= 0.001). Core and mobility training and home-ergonomic instructions were effective to reduce the pain intensity perception and low back functional disability in the EG.

Mutations in the Heme Exporter FLVCR1 Cause Sensory Neurodegeneration with Loss of Pain Perception.

PubMed

Chiabrando, Deborah; Castori, Marco; di Rocco, Maja; Ungelenk, Martin; Gießelmann, Sebastian; Di Capua, Matteo; Madeo, Annalisa; Grammatico, Paola; Bartsch, Sophie; Hübner, Christian A; Altruda, Fiorella; Silengo, Lorenzo; Tolosano, Emanuela; Kurth, Ingo

2016-12-01

Pain is necessary to alert us to actual or potential tissue damage. Specialized nerve cells in the body periphery, so called nociceptors, are fundamental to mediate pain perception and humans without pain perception are at permanent risk for injuries, burns and mutilations. Pain insensitivity can be caused by sensory neurodegeneration which is a hallmark of hereditary sensory and autonomic neuropathies (HSANs). Although mutations in several genes were previously associated with sensory neurodegeneration, the etiology of many cases remains unknown. Using next generation sequencing in patients with congenital loss of pain perception, we here identify bi-allelic mutations in the FLVCR1 (Feline Leukemia Virus subgroup C Receptor 1) gene, which encodes a broadly expressed heme exporter. Different FLVCR1 isoforms control the size of the cytosolic heme pool required to sustain metabolic activity of different cell types. Mutations in FLVCR1 have previously been linked to vision impairment and posterior column ataxia in humans, but not to HSAN. Using fibroblasts and lymphoblastoid cell lines from patients with sensory neurodegeneration, we here show that the FLVCR1-mutations reduce heme export activity, enhance oxidative stress and increase sensitivity to programmed cell death. Our data link heme metabolism to sensory neuron maintenance and suggest that intracellular heme overload causes early-onset degeneration of pain-sensing neurons in humans.

Efficient conditioned pain modulation despite pain persistence in painful diabetic neuropathy

PubMed Central

Granovsky, Yelena; Nahman-Averbuch, Hadas; Khamaisi, Mogher; Granot, Michal

2017-01-01

Abstract Introduction: Alleviation of pain, by either medical or surgical therapy, is accompanied by transition from less efficient, or pro-nociceptive, to efficient conditioned pain modulation (CPM). Spontaneous decrease or resolution of pain with disease progression is reported for some patients with painful diabetic neuropathy (PDN). Objectives: To explore whether CPM changes similarly in parallel to spontaneous resolution of pain in PDN patients. Methods: In this cross-sectional study, thirty-three patients with PDN underwent psychophysical assessment of pain modulation on the forearm, remote from the clinical pain. Results: Pain duration was not correlated with neuropathic pain intensity, yet, it correlated with CPM efficiency; patients with longer pain duration had same pain level, but more efficient CPM than those with short-pain duration (ρ = −0.417; P = 0.025, Spearman correlation). Patients with pain more than 2 years (median split) expressed efficient CPM that was not different from that of healthy controls. These patients also had lower temporal summation of pain than the short-pain duration patients group (P < 0.05). The 2 patient groups did not differ in clinical pain characteristics or use of analgesics. Conclusion: Pro-nociception, expressed by less efficient CPM and high temporal summation that usually accompanies clinical painful conditions, seems to “normalize” with chronicity of the pain syndrome. This is despite continuing pain, suggesting that pro-nociceptivity in pain syndromes is multifactorial. Because the pain modulation profile affects success of therapy, this suggests that different drugs might express different efficacy pending on duration of the pain in patients with PDN. PMID:29392208

Corticomotor excitability during a noxious stimulus before and after exercise in women with fibromyalgia.

PubMed

Hoeger Bement, Marie K; Weyer, Andy D; Yoon, Tejin; Hunter, Sandra K

2014-02-01

The purposes of this study were to assess corticomotor excitability in people with fibromyalgia during a noxious stimulus before and after fatiguing exercise and examine associations with pain perception. Fifteen women with fibromyalgia completed three sessions: one familiarization and two experimental. The experimental sessions were randomized and involved measurement of pain perception and motor evoked potentials before and after (1) quiet rest and (2) isometric contraction of the elbow flexor muscles. Motor evoked potential amplitude of brachioradialis muscle was measured following transcranial magnetic stimulation delivered before, during, and after a noxious mechanical stimulus. After quiet rest, there was no change in pain perception. After the submaximal contraction, there was considerable variability in the pain response. Based on the changes in the experimental pain, subjects were divided into three groups (increase, decrease, and no change in pain). There was an interaction between pain response and the pain-induced change in motor evoked potentials. Those individuals who had an increase in motor evoked potentials during the pain test had an increase in pain after exercise. Thus, women with fibromyalgia were classified based on their pain response to exercise, and this response was associated with the change in corticomotor excitability during the application of a noxious stimulus.

Effect of manipulated state aggression on pain tolerance.

PubMed

Stephens, Richard; Allsop, Claire

2012-08-01

Swearing produces a pain lessening (hypoalgesic) effect for many people; an emotional response may be the underlying mechanism. In this paper, the role of manipulated state aggression on pain tolerance and pain perception is assessed. In a repeated-measures design, pain outcomes were assessed in participants asked to play for 10 minutes a first-person shooter video game vs a golf video game. Sex differences were explored. After playing the first-person shooter video game, aggressive cognitions, aggressive affect, heart rate, and cold pressor latency were increased, and pain perception was decreased. These data indicate that people become more pain tolerant with raised state aggression and support our theory that raised pain tolerance from swearing occurs via an emotional response.

Attention to pain! A neurocognitive perspective on attentional modulation of pain in neuroimaging studies.

PubMed

Torta, D M; Legrain, V; Mouraux, A; Valentini, E

2017-04-01

Several studies have used neuroimaging techniques to investigate brain correlates of the attentional modulation of pain. Although these studies have advanced the knowledge in the field, important confounding factors such as imprecise theoretical definitions of attention, incomplete operationalization of the construct under exam, and limitations of techniques relying on measuring regional changes in cerebral blood flow have hampered the potential relevance of the conclusions. Here, we first provide an overview of the major theories of attention and of attention in the study of pain to bridge theory and experimental results. We conclude that load and motivational/affective theories are particularly relevant to study the attentional modulation of pain and should be carefully integrated in functional neuroimaging studies. Then, we summarize previous findings and discuss the possible neural correlates of the attentional modulation of pain. We discuss whether classical functional neuroimaging techniques are suitable to measure the effect of a fluctuating process like attention, and in which circumstances functional neuroimaging can be reliably used to measure the attentional modulation of pain. Finally, we argue that the analysis of brain networks and spontaneous oscillations may be a crucial future development in the study of attentional modulation of pain, and why the interplay between attention and pain, as examined so far, may rely on neural mechanisms shared with other sensory modalities. Copyright © 2017 Elsevier Ltd. All rights reserved.

No significant correlation between the intensity of static stretching and subject's perception of pain.

PubMed

Lim, Wootaek; Park, Hyunju

2017-10-01

[Purpose] The purpose of this study was to determine whether the intensity of static stretching measured quantitatively is related to subjects' perception of pain. [Subjects and Methods] Sixty-eight participants were recruited. Static stretching was performed once for 30 seconds while maintaining the knee at 0° flexion and was continued to the point where pain was recognized. The intensity of stretching exerted by the practitioner was quantitatively measured by using a handheld dynamometer (HHD). A subject's pain scaled on one's perception was measured by using the visual analog scale (VAS). [Results] No significant correlation was found between the intensity of stretching and the VAS score representing the subject's pain scaled on one's perception. In this study, the most frequent VAS score was 7, and the mean VAS score was 5.57 ± 1.77. The stretching intensity measured by using a HHD ranged from 28.4 to 133.0 N (mean, 72.04 ± 22.37 N). [Conclusion] This study showed that the intensity of stretching quantitatively measured by using HHD did not correlate with the degree of pain reported by the subjects. Therefore, subjective responses cannot guarantee a consistent application of intensity.

Tonic pain and continuous EEG: prediction of subjective pain perception by alpha-1 power during stimulation and at rest.

PubMed

Nir, Rony-Reuven; Sinai, Alon; Moont, Ruth; Harari, Eyal; Yarnitsky, David

2012-03-01

Pain neurophysiology has been chiefly characterized via event-related potentials (ERPs), which are exerted using brief, phase-locked noxious stimuli. Striving for objectively characterizing clinical pain states using more natural, prolonged stimuli, tonic pain has been recently associated with the individual peak frequency of alpha oscillations. This finding encouraged us to explore whether alpha power, reflecting the magnitude of the synchronized activity within this frequency range, will demonstrate a corresponding relationship with subjective perception of tonic pain. Five-minute-long continuous EEG was recorded in 18 healthy volunteers under: (i) resting-state; (ii) innocuous temperature; and (iii) psychophysically-anchored noxious temperature. Numerical pain scores (NPSs) collected during the application of tonic noxious stimuli were tested for correlation with alpha-1 and alpha-2 power. NPSs and alpha power remained stable throughout the recording conditions (Ps⩾0.381). In the noxious condition, alpha-1 power obtained at the bilateral temporal scalp was negatively correlated with NPSs (Ps⩽0.04). Additionally, resting-state alpha-1 power recorded at the bilateral temporal scalp was negatively correlated with NPSs reported during the noxious condition (Ps⩽0.038). Current findings suggest alpha-1 power may serve as a direct, objective and experimentally stable measure of subjective perception of tonic pain. Furthermore, resting-state alpha-1 power might reflect individuals' inherent tonic pain responsiveness. The relevance of alpha-1 power to tonic pain perception may deepen the understanding of the mechanisms underlying the processing of prolonged noxious stimulation. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

A Qualitative Study of Hospitalists' Perceptions of Patient Satisfaction Metrics on Pain Management.

PubMed

Calcaterra, Susan L; Drabkin, Anne D; Doyle, Reina; Leslie, Sarah E; Binswanger, Ingrid A; Frank, Joseph W; Reich, Jennifer A; Koester, Stephen

2017-01-01

Hospital initiatives to promote pain management may unintentionally contribute to excessive opioid prescribing. To better understand hospitalists' perceptions of satisfaction metrics on pain management, the authors conducted 25 interviews with hospitalists. Transcribed interviews were systematically analyzed to identify emergent themes. Hospitalists felt institutional pressure to earn high satisfaction scores for pain, which they perceived influenced practices toward opioid prescribing. They felt tying compensation to satisfaction scores commoditized pain. Hospitalists believed satisfaction would improve with increased time spent at the bedside. Focusing on methods to improve patient-physician communication, while maintaining efficiency in clinical practice, may promote both patient-centered pain management and satisfaction.

Self-reported pain perception of patients after mucosal graft harvesting in the palatal area.

PubMed

Burkhardt, Rino; Hämmerle, Christoph H F; Lang, Niklaus P

2015-03-01

To evaluate the patient-reported pain perception after palatal graft harvesting during a 4 weeks healing period Ninety patients, scheduled for different periodontal and peri-implant plastic surgeries requiring palatal mucosal graft harvesting, were consecutively recruited. Mucosal thickness was measured at the donor sites with an ultrasonic device prior to the surgeries. Graft thickness, length, and width were assessed after harvesting, and the wound areas were calculated. Based on a Visual Analogue Scale (VAS), the patients were asked to report their perceived pain after the intervention and 1, 3, 7, 14, 21 and 28 days thereafter. Pain was most pronounced on the first postoperative day and decreased within the course of time. Graft thickness directly correlated with the amount of pain perceived while increased palatal mucosal thickness before and after graft harvesting decreased pain levels. The denuded wound surface area, however, did not influence the perceived pain level. The wound depth at the donor site (graft thickness) was positively correlated with the patient's perception for pain. The wound surface area, however, did not influence the perceived pain level. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Feelings of Clinician-Patient Similarity and Trust Influence Pain: Evidence From Simulated Clinical Interactions.

PubMed

Losin, Elizabeth A Reynolds; Anderson, Steven R; Wager, Tor D

2017-07-01

Pain is influenced by many factors other than external sources of tissue damage. Among these, the clinician-patient relationship is particularly important for pain diagnosis and treatment. However, the effects of the clinician-patient relationship on pain remain underexamined. We tested the hypothesis that patients who believe they share core beliefs and values with their clinician will report less pain than patients who do not. We also measured feelings of perceived clinician-patient similarity and trust to see if these interpersonal factors influenced pain. We did so by experimentally manipulating perceptions of similarity between participants playing the role of clinicians and participants playing the role of patients in simulated clinical interactions. Participants were placed in 2 groups on the basis of their responses to a questionnaire about their personal beliefs and values, and painful thermal stimulation was used as an analog of a painful medical procedure. We found that patients reported feeling more similarity and trust toward their clinician when they were paired with clinicians from their own group. In turn, patients' positive feelings of similarity and trust toward their clinicians-but not clinicians' feelings toward patients or whether the clinician and patient were from the same group-predicted lower pain ratings. Finally, the most anxious patients exhibited the strongest relationship between their feelings about their clinicians and their pain report. These findings increase our understanding of context-driven pain modulation and suggest that interventions aimed at increasing patients' feelings of similarity to and trust in health care providers may help reduce the pain experienced during medical care. We present novel evidence that the clinician-patient relationship can affect the pain experienced during medical care. We found that "patients" in simulated clinical interactions who reported feeling more similarity and trust toward their "clinicians" reported less pain, suggesting that increasing feelings of clinician-patient similarity and trust may reduce pain disparities. Copyright © 2017 American Pain Society. Published by Elsevier Inc. All rights reserved.

When pain meets … pain-related choice behavior and pain perception in different goal conflict situations.

PubMed

Schrooten, Martien G S; Wiech, Katja; Vlaeyen, Johan W S

2014-11-01

Individuals in pain often face the choice between avoiding pain and pursuing other equally valued goals. However, little is known about pain-related choice behavior and pain perception in goal conflict situations. Seventy-eight healthy volunteers performed a computerized task requiring repeated choices between incompatible options, differing in their effect on probability to receive painful stimulation and money. Depending on group assignment, participants chose between increased pain probability versus decreased money probability (avoidance-avoidance conflict situation); decreased pain probability versus increased money probability (approach-approach conflict situation); or decrease versus increase in both probabilities (double approach/avoidance conflict situation). During the choice task, participants rated painfulness, unpleasantness, threat, and fearfulness associated with the painful stimulation and how they felt. Longer choice latency and more choice switching were associated with higher retrospective ratings of conflict and of decision difficulty, and more equal importance placed on pain avoidance and earning money. Groups did not differ in choice behavior, pain stimulus ratings, or affect. Across groups, longer choice latencies were nonsignificantly associated with higher pain, unpleasantness, threat, and fearfulness. In the avoidance-avoidance group, more choice switching was associated with higher pain-related threat and fearfulness, and with more negative affect. These results of this study suggest that associations between choice behaviors, pain perception, and affect depend on conflict situation. We present a first experimental demonstration of the relationship between pain-related choice behaviors, pain, and affect in different goal conflict situations. This experimental approach allows us to examine these relationships in a controlled fashion. Better understanding of pain-related goal conflicts and their resolution may lead to more effective pain treatment. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

Efficacy of the "body movement and perception" method in the treatment of fibromyalgia syndrome: an open pilot study.

PubMed

Maddali Bongi, S; Di Felice, C; Del Rosso, A; Landi, G; Maresca, M; Giambalvo Dal Ben, G; Matucci-Cerinic, M

2011-01-01

Group exercises may be useful in fibromyalgia syndrome (FMS). The 'Body movement and perception' (BMP) method is based on low impact exercises, awareness of body perception and relaxation, aimed at treating small groups of patients following the Resseguier method (RM) and integrating RM with exercises derived from soft gymnastics. We assessed the effects of BMP method on FMS. 40 women with FMS (age and disease duration: 51.7±7.2 and 4.9±3.8 years) participated in an open pilot study. BMP sessions were performer twice a week (50 minutes each) for 8 weeks. Patients were assessed at enrolment (T0) and at the end of the study (T1) by a self-administered questionnaire (temporal characteristics of pain, pain interference in working and recreational activities and in night-time rest, awareness of pain, fatigue, irritability, well-being, quality of movement, ability to focus on perception and to perceive whole body, postural selfcontrol, ability to relax) and a clinical evaluation (tender points, assumption of analgesics/NSAIDs, distribution of pain, pain in sitting and standing position, pain during postural passages and gait, postural body alignment, muscular contractures). At T1, FMS patients significantly improved with respect to T0 in pain, fatigue, irritability, well-being, quality of movement, postural self-control, ability to relax mind and body, movement perception, tender point scores, assumption of analgesic/NSAIDs, body alignment and muscle contractures (p<0.05 for all the comparisons T1 versus T0). In FMS patients, rehabilitation with BMP improves pain and well being, reduces the number of tender points and muscle contractures, thus it is useful in FMS management.

[Chronic Pelvic Pain Syndrome and Personality--Association of Somatic Symptoms and Psychic Structure].

PubMed

Albrecht, Rebecca; Löwe, Bernd; A Brünahl, Christian; Riegel, Björn

2015-11-01

Despite its high prevalence, little is known about the aetiology and maintenance of Chronic Pelvic Pain Syndrome (CPPS). CPPS is is considered to be a multi-causal syndrome with discomfort and pain in the pelvis. Recent literature suggests that psychosocial factors are important for understanding CPPS. For example, CPPS has been associated with deficits in mentalization and bonding experiences. Our study aims to characterize features of personality disorders according to DSM-IV and psychic structure according to OPD-2 in CPPS patients. Furthermore, we examine the association of personality aspects with urological symptoms (NIH Questionnaire) and pain perception (MPQ Questionnaire). Personality aspects were assessed in a total of 109 patients from our CPPS outpatient clinic using standardized questionnaires. To characterize CPPS patients, we compared the sample's scores with reference groups, mostly the general population. In addition, the associations between personality aspects and both the urologic symptoms and pain perception were assessed using correlations. Missing data were replaced using multiple imputation methods. Compared to reference values, we found 'experiencing emotions' and 'creating relationships' as specific deficits in CPPS patients. Furthermore, patients' self-image (more dominant, higher depressive mood) differs from the general population. A higher pain perception was correlated with deficits in most personality aspects we measured. However, this was not the case for the severity of urological symptoms. Compared to the reference values, only a few personality aspects differed in CPPS patients but there was a correlational association between different personality traits and pain perception. Despite the extend of symptoms, pain perception is associated with difficulty (emotional ability) in dealing with emotions, self-management and relationships. These personality aspects should be taken into account when planning therapy. © Georg Thieme Verlag KG Stuttgart · New York.

Examining the relationship between endogenous pain modulation capacity and endurance exercise performance.

PubMed

Flood, Andrew; Waddington, Gordon; Cathcart, Stuart

2017-01-01

The aim of the current study was to examine the relationship between pain modulatory capacity and endurance exercise performance. Twenty-seven recreationally active males between 18 and 35 years of age participated in the study. Pain modulation was assessed by examining the inhibitory effect of a noxious conditioning stimulus (cuff occlusion) on the perceived intensity of a second noxious stimulus (pressure pain threshold). Participants completed two, maximal voluntary contractions followed by a submaximal endurance time task. Both performance tasks involved an isometric contraction of the non-dominant leg. The main analysis uncovered a correlation between pain modulatory capacity and performance on the endurance time task (r = -.425, p = .027), such that those with elevated pain modulation produced longer endurance times. These findings are the first to demonstrate the relationship between pain modulation responses and endurance exercise performance.

[Cross-sectional field pain medicine Q14 - the Mainz model : Development of the pain medicine curriculum in the standard study course at the University Medical School of the Johannes Gutenberg University Mainz].

PubMed

Kurz, S; Buggenhagen, H; Schwab, R; Laufenberg-Feldmann, R

2017-10-01

Following the amendment of the Medical Licensure Act (ÄAppO) in 2012, pain medicine was introduced as a mandatory subject for students during undergraduate medical training. Medical schools were required to define and to implement adequate curricular and formal teaching structures based on interdisciplinary and multiprofessional requirements according to the curriculum for pain medicine of the German Pain Society. These aspects were considered in the new interdisciplinary curriculum for pain medicine, the so-called Mainz model. A new curriculum based on the Kern cycle was developed and implemented at the Medical Center of the Johannes Gutenberg University in Mainz. Different teaching methods (lectures, interprofessional tutorials and bedside coaching in small groups) were used to impart professional expertise in pain medicine to medical students in an interdisciplinary clinical context. The new curriculum was put into practice and evaluated starting from the winter semester 2014/2015. Before and after the first implementation, medical students were asked about the relevance of pain medicine and their perception of personal competence. The interdisciplinary course in pain medicine was successfully introduced into the degree program based on the curriculum of the German Pain Society and the Kern cycle. With educational support, interdepartmental and multiprofessional collaboration the process of implementation of new interdisciplinary courses can be facilitated. In the future, the question how to increase the amount of practical lessons without increasing the load on teaching resources has to be resolved. Blended learning modules, such as a combination of E‑learning and practical lessons are currently being studied in smaller cohorts.

Effects of (S)-3,4-DCPG, an mGlu8 receptor agonist, on inflammatory and neuropathic pain in mice.

PubMed

Marabese, I; de Novellis, V; Palazzo, E; Scafuro, M A; Vita, D; Rossi, F; Maione, S

2007-02-01

In this study, the effect of (S)-3,4-dicarboxyphenylglycine (DCPG), a selective mGlu8 receptor agonist, has been investigated in inflammatory and neuropathic pain models in order to elucidate the role of mGlu8 receptor in modulating pain perception. Inflammatory pain was induced by the peripheral injection of formalin or carrageenan in awake mice. Systemic administration of (S)-3,4-DCPG, performed 15 min before formalin, decreased both early and delayed nociceptive responses of the formalin test. When this treatment was carried out 15 min after the peripheral injection of formalin it still reduced the late hyperalgesic phase. Similarly, systemic (S)-3,4-DCPG reduced carrageenan-induced thermal hyperalgesia and mechanical allodynia when administered 15 min before carrageenan, but no effect on pain behaviour was observed when (S)-3,4-DCPG was given after the development of carrageenan-induced inflammatory pain. When microinjected into the lateral PAG (RS)-alpha-methylserine-O-phoshate (MSOP), a group III receptor antagonist, antagonised the analgesic effect induced by systemic administration of (S)-3,4-DCPG in both of the inflammatory pain models. Intra-lateral PAG (S)-3,4-DCPG reduced pain behaviour when administered 10 min before formalin or carrageenan; both the effects were blocked by intra-lateral PAG MSOP. (S)-3,4-DCPG was ineffective in alleviating thermal hyperalgesia and mechanical allodynia 7 days after the chronic constriction injury of the sciatic nerve, whereas it proved effective 3 days after surgery. Taken together these results suggest that stimulation of mGlu8 receptors relieve formalin and carrageenan-induced hyperalgesia in inflammatory pain, whereas it would seem less effective in established inflammatory or neuropathic pain.

"I've Actually Changed How I Live"-Patients' Long-Term Perceptions of a Cognitive Behavioral Pain Management Program.

PubMed

Egan, Aine; Lennon, Olive; Power, Camillus K; Fullen, Brona M

2017-02-01

To determine patients’ perceptions regarding cognitive behavioral pain management programs, and to determine what, if any, strategies learned on the program patients continue to use long-term to manage their pain. A qualitative, focus-group based study. An outpatient multidisciplinary pain management program in a university teaching hospital. Patients with chronic pain who had previously completed a 4-week cognitive behavioral pain management program (2001–2014). Sixteen patients attended one of four focus groups. A battery of semi-structured questions explored their perceptions of the cognitive behavioral program, and which strategies they found useful and continued to use long-term to manage their pain. Six key themes emerged: 1) universal long-term positive feedback on the utility of the program; 2) the program facilitated long-term changes in daily life; 3) participants now considered themselves as the “new me”; 4) request for more updates on emerging new treatments/pain knowledge; 5) recognizing that the key to maximizing gain from the program was to be open, to listen, and accept; and 6) participants sharing pain management knowledge with others in pain. There was universal positive feedback for the pain management program. Despite the years since they participated in one, patients continue to use key strategies to effectively manage their pain (pacing, relaxation), embedding them in their daily lives to maximize their quality of life.

Reductions in Perceived Injustice are Associated With Reductions in Disability and Depressive Symptoms After Total Knee Arthroplasty.

PubMed

Yakobov, Esther; Scott, Whitney; Stanish, William D; Tanzer, Michael; Dunbar, Michael; Richardson, Glen; Sullivan, Michael J L

2018-05-01

Perceptions of injustice have been associated with problematic recovery outcomes in individuals with a wide range of debilitating pain conditions. It has been suggested that, in patients with chronic pain, perceptions of injustice might arise in response to experiences characterized by illness-related pain severity, depressive symptoms, and disability. If symptoms severity and disability are important contributors to perceived injustice (PI), it follows that interventions that yield reductions in symptom severity and disability should also contribute to reductions in perceptions of injustice. The present study examined the relative contributions of postsurgical reductions in pain severity, depressive symptoms, and disability to the prediction of reductions in perceptions of injustice. The study sample consisted of 110 individuals (69 women and 41 men) with osteoarthritis of the knee scheduled for total knee arthroplasty (TKA). Patients completed measures of perceived injustice, depressive symptoms, pain, and disability at their presurgical evaluation, and at 1-year follow-up. The results revealed that reductions in depressive symptoms and disability, but not pain severity, were correlated with reductions in perceived injustice. Regression analyses revealed that reductions in disability and reductions in depressive symptoms contributed modest but significant unique variance to the prediction of postsurgical reductions in perceived injustice. The present findings are consistent with current conceptualizations of injustice appraisals that propose a central role for symptom severity and disability as determinants of perceptions of injustice in patients with persistent pain. The results suggest that the inclusion of psychosocial interventions that target depressive symptoms and perceived injustice might augment the impact of rehabilitation programs made available for individuals recovering from TKA.

Interactions among sex, ethnicity, religion, and gender role expectations of pain.

PubMed

Defrin, Ruth; Eli, Ilana; Pud, Dorit

2011-06-01

Sex, gender, ethnicity, and religion are powerful factors that may affect pain experience. Recently, gender role expectations of pain (GREP) were suggested to account for some of the differences in pain perception between men and women. However, the interaction between GREP and ethnicity and religion was not examined. This interaction was studied with regard to pain sensitivity, pain endurance, and willingness to report pain. Our objective was to study the interaction among GREP, sex, and ethno-religious belonging. Participants (548 healthy men and women) of 3 different ethno-religious groups (341 Jews, 105 Muslim-Arabs, 102 Christian-Arabs) completed the GREP questionnaire; pain sensitivity, pain endurance, and willingness to report pain were analyzed. Men of all 3 ethno-religious groups perceived themselves and other men as less sensitive and less willing to report pain than typical women. Women of all 3 ethno-religious groups perceived themselves and other women as more sensitive and more willing to report pain than men. Ethno-religious differences were observed in the attitudes towards typical men and women, with Christian men and women exhibiting stronger stereotypical views regarding pain sensitivity and pain endurance. Individual's perceptions of pain regarding one's self compared with the same or opposite sex were similar regardless of ethno-religious belonging and were related to sex. However, attitudes on pain of typical men and women seemed to be influenced by ethno-religious belonging. This differential effect of ethno-religion on GREP with relation to sex suggests that these factors should be considered when pain perception is evaluated. Copyright © 2011 Elsevier HS Journals, Inc. All rights reserved.

Nursing ward managers' perceptions of pain prevalence at the aged-care facilities in Japan: a nationwide survey.

PubMed

Takai, Yukari; Yamamoto-Mitani, Noriko; Fukahori, Hiroki; Kobayashi, Sayuri; Chiba, Yumi

2013-09-01

This study aimed to examine nursing ward managers' perceptions of pain prevalence among older residents and the strategies of pain management at the Health Service Facilities for the Elderly Requiring Care (HSFERC) in Japan and to investigate the factors related to the prevalence. Nursing ward managers in 3,644 HSFERC were asked to participate in this study. Questionnaires were sent to them regarding pain prevalence among the older residents in their wards, their provisions for pain care, and other pain management strategies. The perceived pain prevalence factors were examined statistically. The final sample comprised 439 participants (12.0%). A total of 5,219 residents (22.3%) were recognized as suffering from pain on the investigation day. Only 8 wards (1.8%) used pain management guidelines or care manuals, and 14 (3.2%) used a standardized pain scale. The ward managers' age (p = .008) and nursing experience (p = .006) showed a significant negative association with pain prevalence estimation. Moreover, there was a significant association between the groups' pain prevalence estimation and the nursing managers' beliefs that older adults were less sensitive to pain (p = .01), that pain was common among older people (p = .007), and that the time to treat residents' pain was insufficient (p = .001). The ward managers' perceptions regarding pain prevalence varied; the perceived pain rates were possibly lower than the actual percentages. Insufficient pain management strategies at the HSFERC were also suggested. An appropriate pain management strategy for Japanese aged care and its dissemination are urgently required. Copyright © 2013 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Influence of structural integration and fascial fitness on body image and the perception of back pain.

PubMed

Baur, Heidi; Gatterer, Hannes; Hotter, Barbara; Kopp, Martin

2017-06-01

[Purpose] The aim of this study was to examine the influence of Structural Integration and Fascial Fitness, a new form of physical exercise, on body image and the perception of back pain. [Subjects and Methods] In total, 33 participants with non-specific back pain were split into two groups and performed three sessions of Structural Integration or Fascial Fitness within a 3-week period. Before and after the interventions, perception of back pain and body image were evaluated using standardized questionnaires. [Results] Structural Integration significantly decreased non-specified back pain and improved both "negative body image" and "vital body dynamics". Fascial Fitness led to a significant improvement on the "negative body image" subscale. Benefits of Structural Integration did not significantly vary in magnitude from those for fascial fitness. [Conclusion] Both Structural Integration and Fascial Fitness can lead to a more positive body image after only three sessions. Moreover, the therapeutic technique of Structural Integration can reduce back pain.

Aberrant pain perception in direct and indirect non-suicidal self-injury: an empirical test of Joiner's interpersonal theory.

PubMed

St Germain, Sarah A; Hooley, Jill M

2013-08-01

Using a community sample (N=148) we examined pressure pain perception in 3 study groups--people who engaged in non-suicidal self-injury, people who engaged in indirect forms of self-injury, and non-self-injuring controls. In so doing we tested hypotheses derived from Joiner's (2005) interpersonal theory of suicide. Consistent with previous studies and with Joiner's model, people who engaged in NSSI endured pain for significantly longer than non-self-injuring controls. Importantly, pain endurance in the Indirect self-injury group was comparable to that found in the NSSI group and significantly elevated relative to controls. This pattern of results suggests that abnormal pain perception may not be specific to forms of self-injury (e.g., NSSI) that involve immediate physical pain (e.g., cutting). Our findings further suggest that the concept of acquired capability for suicide might have relevance for both direct and indirect forms of self-injurious behavior. Copyright © 2013 Elsevier Inc. All rights reserved.

Barriers to Using Nonpharmacologic Approaches and Reducing Opioid Use in Primary Care.

PubMed

Giannitrapani, Karleen F; Ahluwalia, Sangeeta C; McCaa, Matthew; Pisciotta, Maura; Dobscha, Steven; Lorenz, Karl A

2017-10-20

Opioid prescribing for chronic pain, including the potential for over-reliance and misuse, is a public health concern. In the context of Veterans Administration (VA) primary care team-based pain management, we aimed to understand providers' perceptions of barriers to reducing opioid use and improving the use of nonpharmacologic pain management therapies (NPTs) for chronic pain. A semistructured interview elucidated provider experiences with assessing and managing pain. Emergent themes were mapped to known dimensions of VA primary care access. Informants included 60 primary care providers, registered nurses, licensed practical nurses, clerks, psychologists, and social workers at two VA Medical Centers. Nine multidisciplinary focus groups. Provider perceptions of barriers to reducing opioids and improving use of NPTs for patients with chronic pain clustered around availability and access. Barriers to NPT access included the following subthemes: geographical (patient distance from service), financial (out-of-pocket cost to patient), temporal (treatment time delays), cultural (belief that NPTs increased provider workload, perception of insufficient training on NPTs, perceptions of patient resistance to change, confrontation avoidance, and insufficient leadership support), and digital (measure used for pain assessment, older patients hesitant to use technology, providers overwhelmed by information). Decreasing reliance on opioids for chronic pain requires a commitment to local availability and provider-facing strategies that increase efficacy in prescribing NPTs. Policies and interventions for decreasing utilization of opioids and increasing use of NPTs should comprehensively consider access barriers. 2017 American Academy of Pain Medicine. This work is written by US Government employees and is in the public domain in the US.

Conservative nature of oestradiol signalling pathways in the brain lobes of octopus vulgaris involved in reproduction, learning and motor coordination.

PubMed

De Lisa, E; Paolucci, M; Di Cosmo, A

2012-02-01

Oestradiol plays crucial roles in the mammalian brain by modulating reproductive behaviour, neural plasticity and pain perception. The cephalopod Octopus vulgaris is considered, along with its relatives, to be the most behaviourally advanced invertebrate, although the neurophysiological basis of its behaviours, including pain perception, remain largely unknown. In the present study, using a combination of molecular and imaging techniques, we found that oestradiol up-regulated O. vulgaris gonadotrophin-releasing hormone (Oct-GnRH) and O. vulgaris oestrogen receptor (Oct-ER) mRNA levels in the olfactory lobes; in turn, Oct-ER mRNA was regulated by NMDA in lobes involved in learning and motor coordination. Fluorescence resonance energy transfer analysis revealed that oestradiol binds Oct-ER causing conformational modifications and nuclear translocation consistent with the classical genomic mechanism of the oestrogen receptor. Moreover, oestradiol triggered a calcium influx and cyclic AMP response element binding protein phosphorylation via membrane receptors, providing evidence for a rapid nongenomic action of oestradiol in O. vulgaris. In the present study, we demonstrate, for the first time, the physiological role of oestradiol in the brain lobes of O. vulgaris involved in reproduction, learning and motor coordination. © 2011 The Authors. Journal of Neuroendocrinology © 2011 Blackwell Publishing Ltd.

Pain perception and nonsuicidal self-injury: a laboratory investigation.

PubMed

Hooley, Jill M; Ho, Doreen T; Slater, Joshua; Lockshin, Amanda

2010-07-01

People who engage in self-injurious behaviors such as cutting and burning may have altered pain perception. Using a community sample, we examined group differences in pain threshold and pain endurance between participants who self-injured and control participants who were exposed to pressure pain applied to the finger. Participants who self-injured had higher pain thresholds (time to report pain) and endured pain for longer than control participants. Among participants who self-injured, those with longer histories of self-injury had higher pain thresholds. Duration of self-injury was unrelated to pain endurance. Instead, greater pain endurance was predicted by higher levels of introversion and neuroticism and by more negative beliefs about one's self-worth. A highly self-critical cognitive style was the strongest predictor of prolonged pain endurance. People who self-injure may regard suffering and pain as something that they deserve. Our findings also have implications for understanding factors that might be involved in the development and maintenance of self-injury. PsycINFO Database Record (c) 2010 APA, all rights reserved

Identification of Indirect Effects in a Cognitive Patient Education (COPE) Intervention for Low Back Pain.

PubMed

Mansell, Gemma; Storheim, Kjersti; Løchting, Ida; Werner, Erik L; Grotle, Margreth

2017-12-01

Many interventions for the treatment of low back pain exist, but the mechanisms through which such treatments work are not always clear. This situation is especially true for biopsychosocial interventions that incorporate several different components and methods of delivery. The study objective was to examine the indirect effects of the Cognitive Patient Education (COPE) intervention via illness perceptions, back pain myths, and pain catastrophizing on disability outcome. This study was a secondary analysis of the COPE randomized controlled trial. Mediation analysis techniques were employed to examine the indirect effects of the COPE intervention via residualized change (baseline - posttreatment) in the 3 variables hypothesized to be targeted by the COPE intervention on posttreatment disability outcome. Pain intensity at baseline, pain duration, clinician type, and a treatment-mediator interaction term were controlled for in the analysis. Preliminary analyses confirmed that changes in pain catastrophizing and illness perceptions (not back pain myths) were related to both allocation to the intervention arm and posttreatment disability score. The treatment exerted statistically significant indirect effects via changes in illness perceptions and pain catastrophizing on posttreatment disability score (illness perceptions standardized indirect effect = 0.09 [95% CI = 0.03 to 0.16]; pain catastrophizing standardized indirect effect = 0.05 [95% CI = 0.01 to 0.12]). However, the inclusion of an interaction term led to the indirect effects being significantly reduced, with the effects no longer being statistically significant. This study presents a secondary analysis of variables not identified a priori as being potentially important treatment targets; other, unmeasured factors could also be important in explaining treatment effects. The finding that small indirect effects of the COPE intervention via changes in illness perceptions and pain catastrophizing on posttreatment disability could be estimated indicates that these variables may be viable treatment targets for biopsychosocial interventions; however, this finding must be viewed in light of the adjusted analyses, which showed that the indirect effects were significantly reduced through the inclusion of a treatment-mediator interaction term. © Crown copyright 2015

Visceral Pain: The Neurophysiological Mechanism

PubMed Central

Sengupta, Jyoti N.

2011-01-01

The mechanism of visceral pain is still less understood compared with that of somatic pain. This is primarily due to the diverse nature of visceral pain compounded by multiple factors such as sexual dimorphism, psychological stress, genetic trait, and the nature of predisposed disease. Due to multiple contributing factors there is an enormous challenge to develop animal models that ideally mimic the exact disease condition. In spite of that, it is well recognized that visceral hypersensitivity can occur due to (1) sensitization of primary sensory afferents innervating the viscera, (2) hyperexcitability of spinal ascending neurons (central sensitization) receiving synaptic input from the viscera, and (3) dysregulation of descending pathways that modulate spinal nociceptive transmission. Depending on the type of stimulus condition, different neural pathways are involved in chronic pain. In early-life psychological stress such as maternal separation, chronic pain occurs later in life due to dysregulation of the hypothalamic–pituitary–adrenal axis and significant increase in corticotrophin releasing factor (CRF) secretion. In contrast, in early-life inflammatory conditions such as colitis and cystitis, there is dysregulation of the descending opioidergic system that results excessive pain perception (i.e., visceral hyperalgesia). Functional bowel disorders and chronic pelvic pain represent unexplained pain that is not associated with identifiable organic diseases. Often pain overlaps between two organs and approximately 35% of patients with chronic pelvic pain showed significant improvement when treated for functional bowel disorders. Animal studies have documented that two main components such as (1) dichotomy of primary afferent fibers innervating two pelvic organs and (2) common convergence of two afferent fibers onto a spinal dorsal horn are contributing factors for organ-to-organ pain overlap. With reports emerging about the varieties of peptide molecules involved in the pathological conditions of visceral pain, it is expected that better therapy will be achieved relatively soon to manage chronic visceral pain. PMID:19655104

Physiological and Psychological Predictors of Short-Term Disability in Workers with a History of Low Back Pain: A Longitudinal Study

PubMed Central

Dubois, Jean-Daniel; Cantin, Vincent; Piché, Mathieu; Descarreaux, Martin

2016-01-01

Despite an elusive pathophysiology, common characteristics are often observed in individuals with chronic low back pain (LBP). These include psychological symptoms, altered pain perception, altered pain modulation and altered muscle activation. These factors have been explored as possible determinants of disability, either separately or in cross-sectional studies, but were never assessed in a single longitudinal study. Therefore, the objective was to determine the relative contribution of psychological and neurophysiological factors to future disability in individuals with past LBP. The study included two experimental sessions (baseline and six months later) to assess cutaneous heat pain and pain tolerance thresholds, pain inhibition, as well as trunk muscle activation. Both sessions included the completion of validated questionnaires to determine clinical pain, disability, pain catastrophizing, fear-avoidance beliefs and pain vigilance. One hundred workers with a history of LBP and 19 healthy individuals took part in the first experimental session. The second experimental session was exclusively conducted on workers with a history of LBP (77/100). Correlation analyses between initial measures and disability at six months were conducted, and measures significantly associated with disability were used in multiple regression analyses. A first regression analysis showed that psychological symptoms contributed unique variance to future disability (R2 = 0.093, p = .009). To control for the fluctuating nature of LBP, a hierarchical regression was conducted while controlling for clinical pain at six months (R2 = 0.213, p < .001) where pain inhibition contributed unique variance in the second step of the regression (R2 change = 0.094, p = .005). These results indicate that pain inhibition processes may constitute potential targets for treatment to alleviate future disability in individuals with past or present LBP. Then again, the link between psychological symptoms and pain inhibition needs to be clarified as both of these factors are linked together and influence disability in their own way. PMID:27783666

Patient's pain perception during mandibular molar extraction with articaine: a comparison study between infiltration and inferior alveolar nerve block.

PubMed

Bataineh, Anwar B; Alwarafi, Majid A

2016-11-01

The aim of this study was to investigate the effectiveness of a local anesthetic agent comprising of 4 % articaine with 1:100,000 adrenaline, administered through an infiltration technique prior to the extraction of mandibular permanent first molar teeth. The study adopted a split mouth approach and involved patients who needed simple extractions of permanent mandibular first molar teeth on both sides. A combination of buccal and lingual infiltrations was used on one side, while the conventional inferior alveolar nerve block (IANB) technique, with a 1.8-ml cartridge of 4 % articaine with 1:100,000 epinephrine, was administered to the other. The patients' pain perception was assessed using visual analogue scale (VAS) and verbal rating scale (VRS) after the injection, followed by extraction. As a part of the study, 104 teeth were extracted from mouths of 52 patients. The difference in pain perception was statistically insignificant (p > .05) regarding the local anesthetic injection between the two techniques. The difference in pain perception regarding the extraction between the two techniques was also statistically insignificant (p < .05). No difference in pain perception between the two techniques among the study population was noted. This indicates that the extraction of permanent mandibular first molar teeth is possible without the administration of an IANB with the use of 4 % articaine with 1:100,000 epinephrine. The buccal and lingual infiltrations are slightly less painful than the conventional IANB technique.

Conditioned pain modulation in women with irritable bowel syndrome

USDA-ARS?s Scientific Manuscript database

Evidence suggests that patients with irritable bowel syndrome (IBS) are more vigilant to pain-associated stimuli. The aims of this study were to compare women with IBS (n = 20) to healthy control (HC, n = 20) women on pain sensitivity, conditioned pain modulation (CPM) efficiency, and salivary corti...

Digit ratio (2D:4D) and postoperative pain perception.

PubMed

Kasielska-Trojan, Anna; Stabryła, Piotr; Antoszewski, Bogusław

2017-07-01

It has not been established whether sex differences in pain perception are influenced by prenatal sex hormones. Digit ratio as an indicator of prenatal hormone exposure can be used as a simple measure of the influence of prenatal hormones on pain sensitivity or perception in adulthood. The aim of this study was to determine a correlation between the 2D:4D ratio and pain perception in the postoperative period after rhinoplasty. A prospective cohort study of 100 patients (50 women of the mean age of 30.74±8.09years and 50 men of the mean age of 30.98±10.86years) who underwent posttraumatic rhinoplasty due to the nose trauma in Plastic, Reconstructive and Aesthetic Surgery Clinic. The following measurements were taken the day before a surgery: body height, waist and hip circumference, II and IV digits' lengths and body weight. All subjects filled in a questionnaire including 0-10-point VAS scales to assess postoperative pain 1h after an operation (AO), 6h AO, 12h AO, 24h AO and 48h AO. Women with low 2D:4D reported significantly more pain 1h after an operation than women with high 2D:4D. Similar correlation was observed for low 2D:4D in women 48h AO. In men, low 2D:4D was associated with lower postoperative pain 12h AO (p=0.029). In conclusion, we showed that low 2D:4D in women was associated with high postoperative pain, and low right 2D:4D in men was associated with low postoperative pain. This may suggest that intrauterine estrogen exposure makes women more resistant to pain. Copyright © 2017 Elsevier B.V. All rights reserved.

Disturbed body perception, reduced sleep, and kinesiophobia in subjects with pregnancy-related persistent lumbopelvic pain and moderate levels of disability: An exploratory study.

PubMed

Beales, Darren; Lutz, Alison; Thompson, Judith; Wand, Benedict Martin; O'Sullivan, Peter

2016-02-01

For a small but significant group, pregnancy-related lumbopelvic pain may become persistent. While multiple factors may contribute to disability in this group, previous studies have not investigated sleep impairments, body perception or mindfulness as potential factors associated with disability post-partum. To compare women experiencing no pain post-pregnancy with those experiencing pregnancy-related persistent lumbopelvic pain (either low- or high-level disability) across multiple biopsychosocial domains. Cross-sectional. Participants completed questionnaires for thorough profiling of factors thought to be important in pregnancy-related lumbopelvic pain. Specific measures were the Urinary Distress Inventory, Medical Outcomes Study Sleep Scale, Back Beliefs Questionnaire, Tampa Scale for Kinesiophobia, Depression Anxiety Stress Scale, Coping Strategies Questionnaire, Pain Catastrophising Scale, The Fremantle Back Awareness Questionnaire and the Mindful Attention Awareness Scale. Women where categorised into three groups; pain free (n = 26), mild disability (n = 12) and moderate disability (n = 12) (based on Oswestry Disability Index scores). Non-parametric group comparisons were used to compare groups across the profiling variables. Differences were identified for kinesiophobia (p = 0.03), body perception (p = 0.02), sleep quantity (p < 0.01) and sleep adequacy (p = 0.02). Generally subjects in the moderate disability group had more negative findings for these variables. Disturbances in body-perception, sleep and elevated kinesiophobia were found in pregnancy-related lumbopelvic pain subjects with moderate disability, factors previously linked to persistent low back pain. The cross-sectional nature of this study does not allow for identification of directional pathways between factors. The results support the consideration of these factors in the assessment and management of pregnancy-related lumbopelvic pain. Copyright © 2015 Elsevier Ltd. All rights reserved.

Piloting a Text Message-based Social Support Intervention for Patients With Chronic Pain: Establishing Feasibility and Preliminary Efficacy.

PubMed

Guillory, Jamie; Chang, Pamara; Henderson, Charles R; Shengelia, Rouzi; Lama, Sonam; Warmington, Marcus; Jowza, Maryam; Waldman, Seth; Gay, Geri; Reid, M Carrington

2015-06-01

To examine preliminarily the effectiveness of a short message service (SMS) text message-based social support intervention for reducing daily pain and pain interference levels, improving affect and perceptions of social support in patients with chronic noncancer pain, and exploring the feasibility of a novel mobile application to track perceptions of pain and pain interference. Participants (17 men, 51 women) from 2 pain clinics in New York City downloaded a pain tracking application (App) on their Smartphone and used it to record twice-daily pain, pain interference, and affect scores over the 4-week study period. Participants were randomly assigned to receive standard care (control) or standard care along with receipt of twice-daily supportive SMS text messages delivered during the second and third week of the study (intervention). Demographic and clinical data were obtained at baseline, and social support measures were administered at baseline and at 4 weeks. Statistical analysis was carried out using general linear mixed models, taking into account variances associated with time of assessments and with patients. The social support intervention reduced perceptions of pain and pain interference and improved positive affect for chronic noncancer pain patients assigned to the intervention condition in comparison with controls. Participants completed approximately 80% of the daily measurements requested. These findings establish the feasibility of collecting daily pain data using a mobile tracking App and provide significant implications and insight into a nuanced approach to reducing the daily experience of pain through mobile technology, especially because of its accessibility.

Conditioned pain modulation in patients with nonspecific chronic back pain with chronic local pain, chronic widespread pain, and fibromyalgia.

PubMed

Gerhardt, Andreas; Eich, Wolfgang; Treede, Rolf-Detlef; Tesarz, Jonas

2017-03-01

Findings considering conditioned pain modulation (CPM) in chronic back pain (CBP) are contradictory. This might be because many patients with CBP report pain in further areas of the body, and altered CPM might influence spatial extent of pain rather than CBP per se. Therefore, we compared CPM in patients with CBP with different pain extent. Patients with fibromyalgia syndrome (FMS), for whom CPM impairment is reported most consistently, were measured for comparison. Based on clinical evaluation and pain drawings, patients were categorized into chronic local back pain (CLP; n = 53), chronic widespread back pain (CWP; n = 32), and FMS (n = 92). Conditioned pain modulation was measured by the difference in pressure pain threshold (test stimuli) at the lower back before and after tonic heat pain (conditioning stimulus). We also measured psychosocial variables. Pressure pain threshold was significantly increased in CLP patients after tonic heat pain (P < 0.001) indicating induction of CPM. Conditioned pain modulation in CLP was significantly higher than that in CWP and FMS (P < 0.001), but CPM in CWP and FMS did not differ. Interestingly, a higher number of painful areas (0-10) were associated with lower CPM (r = 0.346, P = 0.001) in CBP but not in FMS (r = -0.013, P = 0.903). Anxiety and depression were more pronounced in FMS than in CLP or CWP (P values <0.01). Our findings suggest that CPM dysfunction is associated with CWP and not with FMS as suggested previously. FMS seems to differ from CWP without FMS by higher psychosocial burden. Moreover, patients with CBP should be stratified into CLP and CWP, and centrally acting treatments targeting endogenous pain inhibition seem to be more indicated the higher the pain extent.

Descending pain modulation in irritable bowel syndrome (IBS): a systematic review and meta-analysis.

PubMed

Chakiath, Rosemary J; Siddall, Philip J; Kellow, John E; Hush, Julia M; Jones, Mike P; Marcuzzi, Anna; Wrigley, Paul J

2015-12-10

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. While abdominal pain is a dominant symptom of IBS, many sufferers also report widespread hypersensitivity and present with other chronic pain conditions. The presence of widespread hypersensitivity and extra-intestinal pain conditions suggests central nervous dysfunction. While central nervous system dysfunction may involve the spinal cord (central sensitisation) and brain, this review will focus on one brain mechanism, descending pain modulation. We will conduct a comprehensive search for the articles indexed in the databases Ovid MEDLINE, Ovid Embase, Ovid PsycINFO and Cochrane Central Register of Controlled Trial (CENTRAL) from their inception to August 2015, that report on any aspect of descending pain modulation in irritable bowel syndrome. Two independent reviewers will screen studies for eligibility, assess risk of bias and extract relevant data. Results will be tabulated and, if possible, a meta-analysis will be carried out. The systematic review outlined in this protocol aims to summarise current knowledge regarding descending pain modulation in IBS. PROSPERO CRD42015024284.

Immediate effects of spinal manipulation on thermal pain sensitivity: an experimental study

PubMed Central

George, Steven Z; Bishop, Mark D; Bialosky, Joel E; Zeppieri, Giorgio; Robinson, Michael E

2006-01-01

Background The underlying causes of spinal manipulation hypoalgesia are largely unknown. The beneficial clinical effects were originally theorized to be due to biomechanical changes, but recent research has suggested spinal manipulation may have a direct neurophysiological effect on pain perception through dorsal horn inhibition. This study added to this literature by investigating whether spinal manipulation hypoalgesia was: a) local to anatomical areas innervated by the lumbar spine; b) correlated with psychological variables; c) greater than hypoalgesia from physical activity; and d) different for A-delta and C-fiber mediated pain perception. Methods Asymptomatic subjects (n = 60) completed baseline psychological questionnaires and underwent thermal quantitative sensory testing for A-delta and C-fiber mediated pain perception. Subjects were then randomized to ride a stationary bicycle, perform lumbar extension exercise, or receive spinal manipulation. Quantitative sensory testing was repeated 5 minutes after the intervention period. Data were analyzed with repeated measures ANOVA and post-hoc testing was performed with Bonferroni correction, as appropriate. Results Subjects in the three intervention groups did not differ on baseline characteristics. Hypoalgesia from spinal manipulation was observed in lumbar innervated areas, but not control (cervical innervated) areas. Hypoalgesic response was not strongly correlated with psychological variables. Spinal manipulation hypoalgesia for A-delta fiber mediated pain perception did not differ from stationary bicycle and lumbar extension (p > 0.05). Spinal manipulation hypoalgesia for C-fiber mediated pain perception was greater than stationary bicycle riding (p = 0.040), but not for lumbar extension (p = 0.105). Conclusion Local dorsal horn mediated inhibition of C-fiber input is a potential hypoalgesic mechanism of spinal manipulation for asymptomatic subjects, but further study is required to replicate this finding in subjects with low back pain. PMID:16911795

Evaluating an Innovative eLearning Pain Education Interprofessional Resource: A Pre-Post Study.

PubMed

Watt-Watson, Judy; McGillion, Michael; Lax, Leila; Oskarsson, Jon; Hunter, Judith; MacLennan, Cameron; Knickle, Kerry; Victor, J Charles

2018-06-20

The challenges of moving the pain education agenda forward are significant worldwide, and resources, including online, are needed to help educators in curriculum development. Online resources are available but with insufficient evaluation in the context of prelicensure pain education. Therefore, this pre-post study examined the impact of an innovative eLearning model: the Pain Education Interprofessional Resource (PEIR) on usability, pain knowledge, beliefs, and understanding of pain assessment skills including empathy. Participants were students (N = 96) recruited from seven prelicensure health sciences programs at the University of Toronto. They worked through three multifaceted modules, developed by an interprofessional team, that followed a patient with acute to persistent postsurgical pain up to one year. Module objectives, content, and assessment were based on International Association for the Study of Pain Pain Curricula domains and related pain core competencies. Multimedia interactive components focused on pain mechanisms and key pain care issues. Outcome measures included previously validated tools; data were analyzed in SPSS. Online exercises provided concurrent individual feedback throughout all modules. The completion rate for modules and online assessments was 100%. Overall usability scores (SD) were strong 4.27/5 (0.56). On average, pain knowledge scores increased 20% (P < 0.001). The Pain Assessment Skills Tool was sensitive to differences in student and expert pain assessment evaluation ratings and was useful as a tool to deliver formative feedback while engaged in interactive eLearning about pain assessment. PEIR is an effective eLearning program with high student ratings for educational design and usability that significantly improved pain knowledge and understanding of collaborative care.

Immediate Changes After Manual Therapy in Patients With Persistent, Nonspecific Back Pain: A Randomized Controlled Trial.

PubMed

Espí-López, Gemma Victoria; Ruescas-Nicolau, Maria-Arantzazu; Sanchez-Sanchez, M Luz; Arnal-Gómez, Anna; Balasch-Bernat, Mercè; Marques-Sule, Elena

2018-02-10

Context • Thoracic manipulation decreases pain and disability. However, when such manipulation is contraindicated, the use of other manual techniques based on the regional interdependence of the thoracic spine, upper ribs, and shoulders is an alternative approach. Objective • The study intended to investigate the immediate changes resulting from 3 manual therapy treatments on spinal mobility, flexibility, comfort, and pain perception in patients with persistent, nonspecific back pain as well as changes in their sense of physical well-being and their perception of change after treatment. Design • The study was a randomized, double-blind, controlled trial. Setting • The study took place in the Department of Physiotherapy of the Faculty of Physiotherapy at the University of Valencia (Valencia, Spain). Participants • Participants were 112 individuals from the community-56.6% female, with a mean age of 21.8 ± 0.2 y-who had persistent, nonspecific back pain. Intervention • Participants were randomly assigned to 1 of 3 groups, receiving (1) neurolymphatic therapy (NL group), (2) articulatory spinal manual therapy (AS group), or (3) articulatory costal manual therapy (AC group). Outcome Measures • Cervical mobility, lumbar flexibility, comfort, pain perception, and physical well-being were assessed at baseline and immediately postintervention. Perception of change was evaluated postintervention. Results • Between baseline and postintervention, the AC group showed a significant increase in cervical flexion (P = .010), whereas the NL and AS groups improved in lumbar flexibility, P = .047 and P = .012, respectively. For that period, significant changes were found in lumbar comfort for the AS group (P < .001) and the NL group (P < .026) and in thoracic comfort (P < .001) for the AC group. All groups improved in physical well-being and pain perception (P < .05). Changes in thoracic comfort, lumbar comfort, and physical well-being differed among the groups, with some differences being statistically significant. Conclusions • All treatments improved pain perception and increased physical well-being. The NL and AS treatments were more effective in lumbar flexibility, the AC treatment in cervical flexion and thoracic comfort, and the NL treatment in lumbar comfort.

Perspectives, perceptions and experiences in postoperative pain management in developing countries: A focus group study conducted in Rwanda

PubMed Central

Johnson, Ana P; Mahaffey, Ryan; Egan, Rylan; Twagirumugabe, Theogene; Parlow, Joel L

2015-01-01

BACKGROUND: Access to postoperative acute pain treatment is an important component of perioperative care and is frequently managed by a multidisciplinary team of anesthesiologists, surgeons, pharmacists, technicians and nurses. In some developing countries, treatment modalities are often not performed due to scarce health care resources, knowledge deficiencies and cultural attitudes. OBJECTIVES: In advance of a comprehensive knowledge translation initiative, the present study aimed to determine the perspectives, perceptions and experiences of anesthesia residents regarding postoperative pain management strategies. METHODS: The present study was conducted using a qualitative assessment strategy in a large teaching hospital in Rwanda. During two sessions separated by seven days, a 10-participant semistructured focus group needs analysis was conducted with anesthesia residents at the Centre Hospitalier Universitaire de Kigali (Kigali, Rwanda). Field notes were analyzed using interpretative and descriptive phenomenological approaches. Participants were questioned regarding their perspectives, perceptions and experiences in pain management. RESULTS: The responses from the focus groups were related to five general areas: general patient and medical practice management; knowledge base regarding postoperative pain management; pain evaluation; institutional/system issues related to protocol implementation; and perceptions about resource allocation. Within these areas, challenges (eg, communication among stakeholders and with patients) and opportunities (eg, on-the-job training, use of protocols, routine pain assessment, participation in resource allocation decisions) were identified. CONCLUSIONS: The present study revealed the prevalent challenges residents perceive in implementing postoperative pain management strategies, and offers practical suggestions to overcoming them, primarily through training and the implementation of practice recommendations. PMID:26448971

Psychosocial factors partially mediate the relationship between mechanical hyperalgesia and self-reported pain.

PubMed

Mason, Kayleigh J; O'Neill, Terence W; Lunt, Mark; Jones, Anthony K P; McBeth, John

2018-01-26

Amplification of sensory signalling within the nervous system along with psychosocial factors contributes to the variation and severity of knee pain. Quantitative sensory testing (QST) is a non-invasive test battery that assesses sensory perception of thermal, pressure, mechanical and vibration stimuli used in the assessment of pain. Psychosocial factors also have an important role in explaining the occurrence of pain. The aim was to determine whether QST measures were associated with self-reported pain, and whether those associations were mediated by psychosocial factors. Participants with knee pain identified from a population-based cohort completed a tender point count and a reduced QST battery of thermal, mechanical and pressure pain thresholds, temporal summation, mechanical pain sensitivity (MPS), dynamic mechanical allodynia (DMA) and vibration detection threshold performed following the protocol by the German Research Network on Neuropathic Pain. QST assessments were performed at the most painful knee and opposite forearm (if pain-free). Participants were asked to score for their global and knee pain intensities within the past month (range 0-10), and complete questionnaire items investigating anxiety, depression, illness perceptions, pain catastrophising, and physical functioning. QST measures (independent variable) significantly correlated (Spearman's rho) with self-reported pain intensity (dependent variable) were included in structural equation models with psychosocial factors (latent mediators). Seventy-two participants were recruited with 61 participants (36 women; median age 64 years) with complete data included in subsequent analyses. Tender point count was significantly correlated with global pain intensity. DMA at the knee and MPS at the most painful knee and opposite pain-free forearm were significantly correlated with both global pain and knee pain intensities. Psychosocial factors including pain catastrophising sub-scales (rumination and helplessness) and illness perceptions (consequences and concern) were significant partial mediators of the association with global pain intensity when loaded on to a latent mediator for: tender point count [75% total effect; 95% confidence interval (CI) 22%, 100%]; MPS at the knee (49%; 12%, 86%); and DMA at the knee (63%; 5%, 100%). Latent psychosocial factors were also significant partial mediators of the association between pain intensity at the tested knee with MPS at the knee (30%; 2%, 58%), but not for DMA at the knee. Measures of mechanical hyperalgesia at the most painful knee and pain-free opposite forearm were associated with increased knee and global pain indicative of altered central processing. Psychosocial factors were significant partial mediators, highlighting the importance of the central integration of emotional processing in pain perception. Associations between mechanical hyperalgesia at the forearm and knee, psychosocial factors and increased levels of clinical global and knee pain intensity provide evidence of altered central processing as a key mechanism in knee pain, with psychological factors playing a key role in the expression of clinical pain.

Brain Functional Changes before, during, and after Clinical Pain.

PubMed

Hu, X; Racek, A J; Bellile, E; Nascimento, T D; Bender, M C; Toback, R L; Burnett, D; Khatib, L; McMahan, R; Kovelman, I; Ellwood, R P; DaSilva, A F

2018-05-01

This study used an emerging brain imaging technique, functional near-infrared spectroscopy (fNIRS), to investigate functional brain activation and connectivity that modulates sometimes traumatic pain experience in a clinical setting. Hemodynamic responses were recorded at bilateral somatosensory (S1) and prefrontal cortices (PFCs) from 12 patients with dentin hypersensitivity in a dental chair before, during, and after clinical pain. Clinical dental pain was triggered with 20 consecutive descending cold stimulations (32° to 0°C) to the affected teeth. We used a partial least squares path modeling framework to link patients' clinical pain experience with recorded hemodynamic responses at sequential stages and baseline resting-state functional connectivity (RSFC). Hemodynamic responses at PFC/S1 were sequentially elicited by expectation, cold detection, and pain perception at a high-level coefficient (coefficients: 0.92, 0.98, and 0.99, P < 0.05). We found that the pain ratings were positively affected only at a moderate level of coefficients by such sequence of functional activation (coefficient: 0.52, P < 0.05) and the baseline PFC-S1 RSFC (coefficient: 0.59, P < 0.05). Furthermore, when the dental pain had finally subsided, the PFC increased its functional connection with the affected S1 orofacial region contralateral to the pain stimulus and, in contrast, decreased with the ipsilateral homuncular S1 regions ( P < 0.05). Our study indicated for the first time that patients' clinical pain experience in the dental chair can be predicted concomitantly by their baseline functional connectivity between S1 and PFC, as well as their sequence of ongoing hemodynamic responses. In addition, this linked cascade of events had immediate after-effects on the patients' brain connectivity, even when clinical pain had already ceased. Our findings offer a better understating of the ongoing impact of affective and sensory experience in the brain before, during, and after clinical dental pain.

Objective correlate of subjective pain perception by contact heat-evoked potentials.

PubMed

Granovsky, Yelena; Granot, Michal; Nir, Rony-Reuven; Yarnitsky, David

2008-01-01

The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.

Efficacy of manual and manipulative therapy in the perception of pain and cervical motion in patients with tension-type headache: a randomized, controlled clinical trial.

PubMed

Espí-López, Gemma V; Gómez-Conesa, Antonia

2014-03-01

The purpose of this study was to evaluate the efficacy of manipulative and manual therapy treatments with regard to pain perception and neck mobility in patients with tension-type headache. A randomized clinical trial was conducted on 84 adults diagnosed with tension-type headache. Eighty-four subjects were enrolled in this study: 68 women and 16 men. Mean age was 39.76 years, ranging from 18 to 65 years. A total of 57.1% were diagnosed with chronic tension-type headache and 42.9% with tension-type headache. Participants were divided into 3 treatment groups (manual therapy, manipulative therapy, a combination of manual and manipulative therapy) and a control group. Four treatment sessions were administered during 4 weeks, with posttreatment assessment and follow-up at 1 month. Cervical ranges of motion pain perception, and frequency and intensity of headaches were assessed. All 3 treatment groups showed significant improvements in the different dimensions of pain perception. Manual therapy and manipulative treatment improved some cervical ranges of motion. Headache frequency was reduced with manipulative treatment (P < .008). Combined treatment reported improvement after the treatment (P < .000) and at follow-up (P < .002). Pain intensity improved after the treatment and at follow-up with manipulative therapy (P < .01) and combined treatment (P < .01). Both treatments, administered both separately and combined together, showed efficacy for patients with tension-type headache with regard to pain perception. As for cervical ranges of motion, treatments produced greater effect when separately administered.

What a car does to your perception: Distance evaluations differ from within and outside of a car.

PubMed

Moeller, Birte; Zoppke, Hartmut; Frings, Christian

2016-06-01

Almost a century ago it was first suggested that cars can be interpreted as tools, but consequences of this assumption were never tested. Research on hand-held tools that are used to manipulate objects in the environment suggests that perception of near space is extended by using tools. Literature on environment perception finds perception of far space to be modulated by the observer's potential to act in the environment. Here we argue that a car increases the action potential and modulates perception of far space in a way similar to how hand-held tools modulate perception of near space. Five distances (4 to 20 meters) were estimated by pedestrians and drivers before and after driving/walking. Drivers underestimated all distances to a larger percentage than did pedestrians. Underestimation was even stronger after driving. We conclude that cars modulate the perception of far distances because they modulate the driver's perception, like a tool typically does, and change the perceived action potential.

Pain Modulation in Waking and Hypnosis in Women: Event-Related Potentials and Sources of Cortical Activity

PubMed Central

De Pascalis, Vilfredo; Varriale, Vincenzo; Cacace, Immacolata

2015-01-01

Using a strict subject selection procedure, we tested in High and Low Hypnotizable subjects (HHs and LHs) whether treatments of hypoalgesia and hyperalgesia, as compared to a relaxation-control, differentially affected subjective pain ratings and somatosensory event-related potentials (SERPs) during painful electric stimulation. Treatments were administered in waking and hypnosis conditions. LHs showed little differentiation in pain and distress ratings between hypoalgesia and hyperalgesia treatments, whereas HHs showed a greater spread in the instructed direction. HHs had larger prefrontal N140 and P200 waves of the SERPs during hypnotic hyperalgesia as compared to relaxation-control treatment. Importantly, HHs showed significant smaller frontocentral N140 and frontotemporal P200 waves during hypnotic hypoalgesia. LHs did not show significant differences for these SERP waves among treatments in both waking and hypnosis conditions. Source localization (sLORETA) method revealed significant activations of the bilateral primary somatosensory (BA3), middle frontal gyrus (BA6) and anterior cingulate cortices (BA24). Activity of these contralateral regions significantly correlated with subjective numerical pain scores for control treatment in waking condition. Moreover, multivariate regression analyses distinguished the contralateral BA3 as the only region reflecting a stable pattern of pain coding changes across all treatments in waking and hypnosis conditions. More direct testing showed that hypnosis reduced the strength of the association of pain modulation and brain activity changes at BA3. sLORETA in HHs revealed, for the N140 wave, that during hypnotic hyperalgesia, there was an increased activity within medial, supramarginal and superior frontal gyri, and cingulated gyrus (BA32), while for the P200 wave, activity was increased in the superior (BA22), middle (BA37), inferior temporal (BA19) gyri and superior parietal lobule (BA7). Hypnotic hypoalgesia in HHs, for N140 wave, showed reduced activity within medial and superior frontal gyri (BA9,8), paraippocampal gyrus (BA34), and postcentral gyrus (BA1), while for the P200, activity was reduced within middle and superior frontal gyri (BA9 and BA10), anterior cingulate (BA33), cuneus (BA19) and sub-lobar insula (BA13). These findings demonstrate that hypnotic suggestions can exert a top-down modulatory effect on attention/preconscious brain processes involved in pain perception. PMID:26030417

Analgesic effect of Facebook: Priming with online social networking may boost felt relatedness that buffers against physical pain.

PubMed

Ho, Liang-Chu; Wu, Wen-Hsiung; Chiou, Wen-Bin

2016-10-01

Social networking sites (SNSs) are extremely popular for providing users with a convenient platform for acquiring social connections and thereby feeling relatedness. Plenty of literature has shown that mental representations of social support can reduce the perception of physical pain. The current study tested whether thinking about SNS would interfere with users' perceptions of experimentally induced pain. Ninety-six undergraduate Facebook users were recruited to participate in a priming-based experiment. They were randomly assigned to one of the three study conditions (SNS prime, neutral prime, or no prime) via rating the aesthetics of logos. The results showed that participants exposed to SNS primes reported less pain of immersion in hot water than did both control groups (neutral- and no-prime). Felt relatedness mediated the link between SNS primes and diminished pain perceptions. This research provides the first demonstration that thinking about SNS can lower experienced physical pain among Facebook users. Online social networking may serve as an analgesic buffer against pain experience than previously thought. The SNS-enabled analgesia has far reaching implications for pain relief applications and the enhancement of well-being in human-interaction techniques. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Using multilevel growth curve modeling to examine emotional modulation of temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR).

PubMed

Rhudy, Jamie L; Martin, Satin L; Terry, Ellen L; Delventura, Jennifer L; Kerr, Kara L; Palit, Shreela

2012-11-01

Emotion can modulate pain and spinal nociception, and correlational data suggest that cognitive-emotional processes can facilitate wind-up-like phenomena (ie, temporal summation of pain). However, there have been no experimental studies that manipulated emotion to determine whether within-subject changes in emotion influence temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR, a physiological measure of spinal nociception). The present study presented a series of emotionally charged pictures (mutilation, neutral, erotic) during which electric stimuli at 2 Hz were delivered to the sural nerve to evoke TS-pain and TS-NFR. Participants (n=46 healthy; 32 female) were asked to rate their emotional reactions to pictures as a manipulation check. Pain outcomes were analyzed using statistically powerful multilevel growth curve models. Results indicated that emotional state was effectively manipulated. Further, emotion modulated the overall level of pain and NFR; pain and NFR were highest during mutilation and lowest during erotic pictures. Although pain and NFR both summated in response to the 2-Hz stimulation series, the magnitude of pain summation (TS-pain) and NFR summation (TS-NFR) was not modulated by picture-viewing. These results imply that, at least in healthy humans, within-subject changes in emotions do not promote central sensitization via amplification of temporal summation. However, future studies are needed to determine whether these findings generalize to clinical populations (eg, chronic pain). Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Influence of catastrophizing, anxiety, and depression on in-hospital opioid consumption, pain, and quality of recovery after adult spine surgery

PubMed Central

Dunn, Lauren K.; Durieux, Marcel E.; Fernández, Lucas G.; Tsang, Siny; Smith-Straesser, Emily E.; Jhaveri, Hasan F.; Spanos, Shauna P.; Thames, Matthew R.; Spencer, Christopher D.; Lloyd, Aaron; Stuart, Russell; Ye, Fan; Bray, Jacob P.; Nemergut, Edward C.; Naik, Bhiken I.

2018-01-01

OBJECTIVE Perception of perioperative pain is influenced by various psychological factors. The aim of this study was to determine the impact of catastrophizing, anxiety, and depression on in-hospital opioid consumption, pain scores, and quality of recovery in adults who underwent spine surgery. METHODS Patients undergoing spine surgery were enrolled in this study, and the preoperatively completed questionnaires included the verbal rating scale (VRS), Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS), and Oswestry Disability Index (ODI). Quality of recovery was assessed using the 40-item Quality of Recovery questionnaire (QoR40). Opioid consumption and pain scores according to the VRS were recorded daily until discharge. RESULTS One hundred thirty-nine patients were recruited for the study, and 101 completed the QoR40 assessment postoperatively. Patients with higher catastrophizing scores were more likely to have higher maximum pain scores postoperatively (estimate: 0.03, SE: 0.01, p = 0.02), without increased opioid use (estimate: 0.44, SE: 0.27, p = 0.11). Preoperative anxiety (estimate: 1.18, SE: 0.65, p = 0.07) and depression scores (estimate: 1.06, SE: 0.71, p = 0.14) did not correlate with increased postoperative opioid use; however, patients with higher preoperative depression scores had lower quality of recovery after surgery (estimate: −1.9, SE: 0.56, p < 0.001). CONCLUSIONS Catastrophizing, anxiety, and depression play important roles in modulating postoperative pain. Preoperative evaluation of these factors, utilizing a validated tool, helps to identify patients at risk. This might allow for earlier psychological intervention that could reduce pain severity and improve the quality of recovery. PMID:29125426

One night of total sleep deprivation promotes a state of generalized hyperalgesia: a surrogate pain model to study the relationship of insomnia and pain.

PubMed

Schuh-Hofer, Sigrid; Wodarski, Rachel; Pfau, Doreen B; Caspani, Ombretta; Magerl, Walter; Kennedy, Jeffrey D; Treede, Rolf-Detlef

2013-09-01

Sleep disturbances are highly prevalent in chronic pain patients. Understanding their relationship has become an important research topic since poor sleep and pain are assumed to closely interact. To date, human experimental studies exploring the impact of sleep disruption/deprivation on pain perception have yielded conflicting results. This inconsistency may be due to the large heterogeneity of study populations and study protocols previously used. In addition, none of the previous studies investigated the entire spectrum of nociceptive modalities. To address these shortcomings, a standardized comprehensive quantitative sensory protocol was used in order to compare the somatosensory profile of 14 healthy subjects (6 female, 8 male, 23.5 ± 4.1 year; mean ± SD) after a night of total sleep deprivation (TSD) and a night of habitual sleep in a cross-over design. One night of TSD significantly increased the level of sleepiness (P<0.001) and resulted in higher scores of the State Anxiety Inventory (P<0.01). In addition to previously reported hyperalgesia to heat (P<0.05) and blunt pressure (P<0.05), study participants developed hyperalgesia to cold (P<0.01) and increased mechanical pain sensitivity to pinprick stimuli (P<0.05) but no changes in temporal summation. Paradoxical heat sensations or dynamic mechanical allodynia were absent. TSD selectively modulated nociception, since detection thresholds of non-nociceptive modalities remained unchanged. Our findings show that a single night of TSD is able to induce generalized hyperalgesia and to increase State Anxiety scores. In the future, TSD may serve as a translational pain model to elucidate the pathomechanisms underlying the hyperalgesic effect of sleep disturbances. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Numeric rating scale: patients' perceptions of its use in postoperative pain assessments.

PubMed

Eriksson, Kerstin; Wikström, Lotta; Årestedt, Kristofer; Fridlund, Bengt; Broström, Anders

2014-02-01

The purpose of this study was to describe how patients perceive the use of the numeric rating scale in postoperative pain assessments. There are recommendations to use a pain scale to follow patients' postoperative pain. Most patients prefer the NRS but there is a discrepancy between patients and healthcare professionals how to interpret the ratings from the pain assessments. A descriptive design with a phenomenographic approach was used. Semi structured interviews were held with 25 patients. Three description categories emerged that illustrate patients' perceptions; use of the NRS facilitated communication of pain, it put demands on healthcare professionals and care routines and it contained interpretation difficulties. The NRS has a place in pain management according to the patients but there is a need for a dialogue to give the patients the opportunity to describe their pain and set a common goal. Copyright © 2014 Elsevier Inc. All rights reserved.

Fetal pain perception and pain management.

PubMed

Van de Velde, Marc; Jani, Jacques; De Buck, Frederik; Deprest, J

2006-08-01

This paper gives an overview of current science related to the concept of fetal pain. We have answered three important questions: (1) does fetal pain exist? (2) does management of fetal pain benefit the unborn child? and (3) which techniques are available to provide good fetal analgesia?

Central Mechanisms in the Maintenance of Chronic Widespread Noninflammatory Muscle Pain

PubMed Central

DeSantana, Josimari M.; Sluka, Kathleen A.

2009-01-01

Chronic widespread pain (CWP) conditions such as fibromyalgia and myofascial syndromes are characterized by generalized pain, tenderness, morning stiffness, disturbed sleep, and pronounced fatigue. However, CWP pathophysiology is still unclear. A number of hypotheses have been proposed as the underlying pathophysiology of CWP: muscular dysfunction/ischemia, central sensitization, and a deficit in endogenous pain-modulating systems. This article reviews the current and emerging literature about the pathophysiology and neurobiology of chronic widespread musculoskeletal pain. Widespread musculoskeletal pain results in changes in the central nervous system in human subjects and animal models. These changes likely reflect alterations in supraspinal modulation of nociception, and include increases in excitatory and decreases in inhibitory modulation pathways. These alterations in excitation and inhibition likely drive changes observed in the spinal cord to result in central sensitization, and the consequent pain and hyperalgesia. PMID:18765138

[Pain in children in historical perspective].

PubMed

Pabis, Emilia; Kowalczyk, Michał; Kulik, Teresa Bernadetta

2010-01-01

Pain in children, especially in infancy, is frequently underestimated. Surprisingly, in ancient times, writers were more aware of the existence of pain in infancy and the need for its relief than in 20th century. They rated pain perception as being higher in infancy than in childhood. The study by McGraw (1941), although badly designed, convinced the vast majority of clinicians that infants do not feel pain and do not require analgesia. This theory, reinforced by the fear of using opioids in young children, dominated medical thinking for more than 30 years. Later studies on pain perception in foetuses, and careful analysis of infants' reactions to blood sampling, helped doctors to understand the necessity of adequate analgesia in young children. In this review, we present the approach to pain in children over centuries, from ancient times to the latest developments in this field.

The relationship between different facets of empathy, pain perception and compassion fatigue among physicians.

PubMed

Gleichgerrcht, Ezequiel; Decety, Jean

2014-01-01

Medical practitioners such as physicians are continuously exposed to the suffering and the distress of patients. Understanding the way pain perception relates to empathetic dispositions and professional quality of life can contribute to the development of strategies aimed at protecting health professionals from burnout and compassion fatigue. In the present study we investigate the way individual dispositions relate to behavioral measures of pain sensitivity, empathy, and professional quality of life. A secure Web-based series of self-report measures and a behavioral task were administered to 1,199 board-certified physicians. Additionally, surveys were used to obtain measures of demographic and professional background; dispositional empathy (empathic concern, personal distress, and perspective taking); positive (compassion satisfaction) and negative (burnout and secondary traumatic stress) aspects of their professional life. In the behavioral task, participants were asked to watch a series of video clips of patients experiencing different levels of pain and provide ratings of pain intensity and induced personal distress. Perceived pain intensity was significantly lower among more experienced physicians but similar across specialty fields with varying demands of emotional stress. Watching videos of patients in pain, however, elicited more personal distress among physicians in highly demanding medical fields, despite comparable empathy dispositions with other fields. The pain of male patients was perceived as less intense than the pain of female patients, and this effect was more marked for female physicians. The effect of dispositional empathy on pain perception and induced personal distress was different for each sub-component, with perspective taking and empathic concern (EC) being predictive of the behavioral outcomes. Physicians who experience both compassion satisfaction and fatigue perceive more pain and suffer more personal distress from it than those who only suffer the negative aspects of professional quality of life. Professional experience seems to desensitize physicians to the pain of others without necessarily helping them down-regulate their own personal distress. Pain perception is also related with specific aspects of empathy and varies depending on context, as is the case with the gender of their patients. Minimum levels of empathy appear necessary to benefit from the positive aspects of professional quality of life in medicine.

Blended-Learning Pain Neuroscience Education for People With Chronic Spinal Pain: Randomized Controlled Multicenter Trial.

PubMed

Malfliet, Anneleen; Kregel, Jeroen; Meeus, Mira; Roussel, Nathalie; Danneels, Lieven; Cagnie, Barbara; Dolphens, Mieke; Nijs, Jo

2018-05-01

Available evidence favors the use of pain neuroscience education (PNE) in patients with chronic pain. However, PNE trials are often limited to small sample sizes and, despite the current digital era, the effects of blended-learning PNE (ie, the combination of online digital media with traditional educational methods) have not yet been investigated. The study objective was to examine whether blended-learning PNE is able to improve disability, catastrophizing, kinesiophobia, and illness perceptions. This study was a 2-center, triple-blind randomized controlled trial (participants, statistician, and outcome assessor were masked). The study took place at university hospitals in Ghent and Brussels, Belgium. Participants were 120 people with nonspecific chronic spinal pain (ie, chronic neck pain and low back pain). The intervention was 3 sessions of PNE or biomedically focused back/neck school education (addressing spinal anatomy and physiology). Measurements were self-report questionnaires (Pain Disability Index, Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, Illness Perception Questionnaire, and Pain Vigilance and Awareness Questionnaire). None of the treatment groups showed a significant change in the perceived disability (Pain Disability Index) due to pain (mean group difference posteducation: 1.84; 95% CI = -2.80 to 6.47). Significant interaction effects were seen for kinesiophobia and several subscales of the Illness Perception Questionnaire, including negative consequences, cyclical time line, and acute/chronic time line. In-depth analysis revealed that only in the PNE group were these outcomes significantly improved (9% to 17% improvement; 0.37 ≤ Cohen d ≥ 0.86). Effect sizes are small to moderate, which might raise the concern of limited clinical utility; however, changes in kinesiophobia exceed the minimal detectable difference. PNE should not be used as the sole treatment modality but should be combined with other treatment strategies. Blended-learning PNE was able to improve kinesiophobia and illness perceptions in participants with chronic spinal pain. As effect sizes remained small to medium, PNE should not be used as a sole treatment but rather should be used as a key element within a comprehensive active rehabilitation program. Future studies should compare the effects of blended-learning PNE with offline PNE and should consider cost-effectiveness.

A machine-learned analysis of human gene polymorphisms modulating persisting pain points at major roles of neuroimmune processes.

PubMed

Kringel, Dario; Lippmann, Catharina; Parnham, Michael J; Kalso, Eija; Ultsch, Alfred; Lötsch, Jörn

2018-06-19

Human genetic research has implicated functional variants of more than one hundred genes in the modulation of persisting pain. Artificial intelligence and machine learning techniques may combine this knowledge with results of genetic research gathered in any context, which permits the identification of the key biological processes involved in chronic sensitization to pain. Based on published evidence, a set of 110 genes carrying variants reported to be associated with modulation of the clinical phenotype of persisting pain in eight different clinical settings was submitted to unsupervised machine-learning aimed at functional clustering. Subsequently, a mathematically supported subset of genes, comprising those most consistently involved in persisting pain, was analyzed by means of computational functional genomics in the Gene Ontology knowledgebase. Clustering of genes with evidence for a modulation of persisting pain elucidated a functionally heterogeneous set. The situation cleared when the focus was narrowed to a genetic modulation consistently observed throughout several clinical settings. On this basis, two groups of biological processes, the immune system and nitric oxide signaling, emerged as major players in sensitization to persisting pain, which is biologically highly plausible and in agreement with other lines of pain research. The present computational functional genomics-based approach provided a computational systems-biology perspective on chronic sensitization to pain. Human genetic control of persisting pain points to the immune system as a source of potential future targets for drugs directed against persisting pain. Contemporary machine-learned methods provide innovative approaches to knowledge discovery from previous evidence. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Smoked medicinal cannabis for neuropathic pain in HIV: a randomized, crossover clinical trial.

PubMed

Ellis, Ronald J; Toperoff, Will; Vaida, Florin; van den Brande, Geoffrey; Gonzales, James; Gouaux, Ben; Bentley, Heather; Atkinson, J Hampton

2009-02-01

Despite management with opioids and other pain modifying therapies, neuropathic pain continues to reduce the quality of life and daily functioning in HIV-infected individuals. Cannabinoid receptors in the central and peripheral nervous systems have been shown to modulate pain perception. We conducted a clinical trial to assess the impact of smoked cannabis on neuropathic pain in HIV. This was a phase II, double-blind, placebo-controlled, crossover trial of analgesia with smoked cannabis in HIV-associated distal sensory predominant polyneuropathy (DSPN). Eligible subjects had neuropathic pain refractory to at least two previous analgesic classes; they continued on their prestudy analgesic regimens throughout the trial. Regulatory considerations dictated that subjects smoke under direct observation in a hospital setting. Treatments were placebo and active cannabis ranging in potency between 1 and 8% Delta-9-tetrahydrocannabinol, four times daily for 5 consecutive days during each of 2 treatment weeks, separated by a 2-week washout. The primary outcome was change in pain intensity as measured by the Descriptor Differential Scale (DDS) from a pretreatment baseline to the end of each treatment week. Secondary measures included assessments of mood and daily functioning. Of 127 volunteers screened, 34 eligible subjects enrolled and 28 completed both cannabis and placebo treatments. Among the completers, pain relief was greater with cannabis than placebo (median difference in DDS pain intensity change, 3.3 points, effect size=0.60; p=0.016). The proportions of subjects achieving at least 30% pain relief with cannabis versus placebo were 0.46 (95%CI 0.28, 0.65) and 0.18 (0.03, 0.32). Mood and daily functioning improved to a similar extent during both treatment periods. Although most side effects were mild and self-limited, two subjects experienced treatment-limiting toxicities. Smoked cannabis was generally well tolerated and effective when added to concomitant analgesic therapy in patients with medically refractory pain due to HIV DSPN.

Smoked Medicinal Cannabis for Neuropathic Pain in HIV: A Randomized, Crossover Clinical Trial

PubMed Central

Ellis, Ronald J; Toperoff, Will; Vaida, Florin; van den Brande, Geoffrey; Gonzales, James; Gouaux, Ben; Bentley, Heather; Atkinson, J Hampton

2011-01-01

Despite management with opioids and other pain modifying therapies, neuropathic pain continues to reduce the quality of life and daily functioning in HIV-infected individuals. Cannabinoid receptors in the central and peripheral nervous systems have been shown to modulate pain perception. We conducted a clinical trial to assess the impact of smoked cannabis on neuropathic pain in HIV. This was a phase II, double-blind, placebo-controlled, crossover trial of analgesia with smoked cannabis in HIV-associated distal sensory predominant polyneuropathy (DSPN). Eligible subjects had neuropathic pain refractory to at least two previous analgesic classes; they continued on their prestudy analgesic regimens throughout the trial. Regulatory considerations dictated that subjects smoke under direct observation in a hospital setting. Treatments were placebo and active cannabis ranging in potency between 1 and 8% Δ-9-tetrahydrocannabinol, four times daily for 5 consecutive days during each of 2 treatment weeks, separated by a 2-week washout. The primary outcome was change in pain intensity as measured by the Descriptor Differential Scale (DDS) from a pretreatment baseline to the end of each treatment week. Secondary measures included assessments of mood and daily functioning. Of 127 volunteers screened, 34 eligible subjects enrolled and 28 completed both cannabis and placebo treatments. Among the completers, pain relief was greater with cannabis than placebo (median difference in DDS pain intensity change, 3.3 points, effect size = 0.60; p = 0.016). The proportions of subjects achieving at least 30% pain relief with cannabis versus placebo were 0.46 (95%CI 0.28, 0.65) and 0.18 (0.03, 0.32). Mood and daily functioning improved to a similar extent during both treatment periods. Although most side effects were mild and self-limited, two subjects experienced treatment-limiting toxicities. Smoked cannabis was generally well tolerated and effective when added to concomitant analgesic therapy in patients with medically refractory pain due to HIV DSPN. PMID:18688212

Independent psychophysical measurement of experimental modulations in the somatotopy of cutaneous heat-pain stimuli.

PubMed

Trojan, Jörg; Kleinböhl, Dieter; Stolle, Annette M; Andersen, Ole K; Hölzl, Rupert; Arendt-Nielsen, Lars

2009-03-01

Distortions of the body image have been repeatedly reported for various clinical conditions, but direct experimental analyses of the perceptual changes involved are still scarce. In addition, most experimental studies rely on cerebral activation patterns to assess neuroplastic changes in central representation, although the relationship between cerebral topography and the topology of the perceptual space is not clear. This study examines whether the direct psychophysical mapping approach we introduced recently (Trojan et al., Brain Res 2006;1120:106-113) is capable of tracking perceptual distortions in the somatotopic representation of heat-pain stimuli. Eleven healthy participants indicated the perceived positions of CO(2) laser stimuli, repetitively presented to the dorsal forearm, with a 3D tracking system in two consecutive sessions, separated by the topical application of capsaicin cream. In line with earlier reports, we expected that the resulting individual perceptual maps (i.e., one-dimensional projections of the perceived positions onto the forearm surface) would be subject to modulation through the altered sensory input, to be measured in terms of altered topological parameters. We found that the topology and metrics of the somatotopic representation were well preserved in the second session, but that the perceptual map was compressed to a smaller range in 9 out of 11 participants. By providing dimensional measures of perceptual representations, perceptual maps constitute an independent, genuinely psychological complement to the topography of cortical activations measured with neuroimaging methods. In addition, we expect them to be useful in diagnosing pathological changes in body perception accompanying chronic pain and other disorders.

Quantitative Sensory Testing and Current Perception Threshold Testing in Patients With Chronic Pain Following Lower Extremity Fracture.

PubMed

Griffioen, Mari A; Greenspan, Joel D; Johantgen, Meg; Von Rueden, Kathryn; O'Toole, Robert V; Dorsey, Susan G; Renn, Cynthia L

2018-01-01

Chronic pain is a significant problem for patients with lower extremity injuries. While pain hypersensitivity has been identified in many chronic pain conditions, it is not known whether patients with chronic pain following lower extremity fracture report pain hypersensitivity in the injured leg. To quantify and compare peripheral somatosensory function and sensory nerve activation thresholds in persons with chronic pain following lower extremity fractures with a cohort of persons with no history of lower extremity fractures. This was a cross-sectional study where quantitative sensory testing and current perception threshold testing were conducted on the injured and noninjured legs of cases and both legs of controls. A total of 14 cases and 28 controls participated in the study. Mean time since injury at the time of testing for cases was 22.3 (standard deviation = 12.1) months. The warmth detection threshold ( p = .024) and nerve activation thresholds at 2,000 Hz ( p < .001) and 250 Hz ( p = .002), respectively, were significantly higher in cases compared to controls. This study suggests that patients with chronic pain following lower extremity fractures may experience hypoesthesia in the injured leg, which contrasts with the finding of hyperesthesia previously observed in other chronic pain conditions but is in accord with patients with nerve injuries and surgeries. This is the first study to examine peripheral sensory nerve function at the site of injury in patients with chronic pain following lower extremity fractures using quantitative sensory testing and current perception threshold testing.

Reward modulates perception in binocular rivalry.

PubMed

Marx, Svenja; Einhäuser, Wolfgang

2015-01-14

Our perception does not provide us with an exact imprint of the outside world, but is continuously adapted to our internal expectations, task sets, and behavioral goals. Although effects of reward-or value in general-on perception therefore seem likely, how valuation modulates perception and how such modulation relates to attention is largely unknown. We probed effects of reward on perception by using a binocular-rivalry paradigm. Distinct gratings drifting in opposite directions were presented to each observer's eyes. To objectify their subjective perceptual experience, the optokinetic nystagmus was used as measure of current perceptual dominance. In a first experiment, one of the percepts was either rewarded or attended. We found that reward and attention similarly biased perception. In a second experiment, observers performed an attentionally demanding task either on the rewarded stimulus, the other stimulus, or both. We found that-on top of an attentional effect on perception-at each level of attentional load, reward still modulated perception by increasing the dominance of the rewarded percept. Similarly, penalizing one percept increased dominance of the other at each level of attentional load. In turn, rewarding-and similarly nonpunishing-a percept yielded performance benefits that are typically associated with selective attention. In conclusion, our data show that value modulates perception in a similar way as the volitional deployment of attention, even though the relative effect of value is largely unaffected by an attention task. © 2015 ARVO.

Knowledge, Perceptions and Attitudes toward Chronic Pain and Its Management: A Cross-Sectional Survey of Frontline Pharmacists in Ontario, Canada

PubMed Central

Patel, Tejal; Chang, Feng; Mohammed, Heba Tallah; Raman-Wilms, Lalitha; Jurcic, Jane; Khan, Ayesha; Sproule, Beth

2016-01-01

The treatment of chronic pain consumes a significant share of primary care. Community and family health team pharmacists frequently see patients with chronic pain, thus have the opportunity to improve their care. To assess the knowledge, perceptions, and attitudes of Ontario pharmacists, we invited 5,324 Ontario pharmacists, to participate in an online survey we developed using Qualtrics. The 31-question survey gathered demographic information, assessed pharmacists’ knowledge of three chronic pain conditions; chronic lower back pain (CLBP, eight true/false statements); chronic headache disorder (CHD, eight true/false statements) and painful diabetic neuropathy (PDN, seven true/false statements), and their attitudes toward and perceptions of patients with these conditions, and knowledge, attitudes, and perceptions of opioids in pain management. We received 688 responses (12.9%) and 392 pharmacists completed the survey. The mean age of respondents was 48.5 years and 48.5% were male. More than 50% of respondents were in practice for more than 20 years and 58.7% worked 25–40 hours per week. The mean knowledge scores were 4.5/8, 5.5/8, and 5.3/8 for CBLP, CHD, and PDN respectively. While 95% of respondents were aware of the increasing death rates due to opioid use, only half were familiar with the Canadian guideline for safe opioid prescribing for non-cancer use. Responses were compared based on gender, time in practice and location of practice. Pharmacists with more than ten years of experience scored significantly higher than those with less experience. Fewer differences were found in comparisons of gender and location of practice. Safe and effective care of chronic pain patients, particularly with opioids, will require additional pharmacist education. PMID:27270723

Knowledge, Perceptions and Attitudes toward Chronic Pain and Its Management: A Cross-Sectional Survey of Frontline Pharmacists in Ontario, Canada.

PubMed

Patel, Tejal; Chang, Feng; Mohammed, Heba Tallah; Raman-Wilms, Lalitha; Jurcic, Jane; Khan, Ayesha; Sproule, Beth

2016-01-01

The treatment of chronic pain consumes a significant share of primary care. Community and family health team pharmacists frequently see patients with chronic pain, thus have the opportunity to improve their care. To assess the knowledge, perceptions, and attitudes of Ontario pharmacists, we invited 5,324 Ontario pharmacists, to participate in an online survey we developed using Qualtrics. The 31-question survey gathered demographic information, assessed pharmacists' knowledge of three chronic pain conditions; chronic lower back pain (CLBP, eight true/false statements); chronic headache disorder (CHD, eight true/false statements) and painful diabetic neuropathy (PDN, seven true/false statements), and their attitudes toward and perceptions of patients with these conditions, and knowledge, attitudes, and perceptions of opioids in pain management. We received 688 responses (12.9%) and 392 pharmacists completed the survey. The mean age of respondents was 48.5 years and 48.5% were male. More than 50% of respondents were in practice for more than 20 years and 58.7% worked 25-40 hours per week. The mean knowledge scores were 4.5/8, 5.5/8, and 5.3/8 for CBLP, CHD, and PDN respectively. While 95% of respondents were aware of the increasing death rates due to opioid use, only half were familiar with the Canadian guideline for safe opioid prescribing for non-cancer use. Responses were compared based on gender, time in practice and location of practice. Pharmacists with more than ten years of experience scored significantly higher than those with less experience. Fewer differences were found in comparisons of gender and location of practice. Safe and effective care of chronic pain patients, particularly with opioids, will require additional pharmacist education.

Long-Time Exposure to Violent Video Games Does Not Show Desensitization on Empathy for Pain: An fMRI Study

PubMed Central

Gao, Xuemei; Pan, Wei; Li, Chao; Weng, Lei; Yao, Mengyun; Chen, Antao

2017-01-01

As a typical form of empathy, empathy for pain refers to the perception and appraisal of others’ pain, as well as the corresponding affective responses. Numerous studies investigated the factors affecting the empathy for pain, in which the exposure to violent video games (VVGs) could change players’ empathic responses to painful situations. However, it remains unclear whether exposure to VVG influences the empathy for pain. In the present study, in terms of the exposure experience to VVG, two groups of participants (18 in VVG group, VG; 17 in non-VVG group, NG) were screened from nearly 200 video game experience questionnaires. And then, the functional magnetic resonance imaging data were recorded when they were viewing painful and non-painful stimuli. The results showed that the perception of others’ pain were not significantly different in brain regions between groups, from which we could infer that the desensitization effect of VVGs was overrated. PMID:28512439

Long-Time Exposure to Violent Video Games Does Not Show Desensitization on Empathy for Pain: An fMRI Study.

PubMed

Gao, Xuemei; Pan, Wei; Li, Chao; Weng, Lei; Yao, Mengyun; Chen, Antao

2017-01-01

As a typical form of empathy, empathy for pain refers to the perception and appraisal of others' pain, as well as the corresponding affective responses. Numerous studies investigated the factors affecting the empathy for pain, in which the exposure to violent video games (VVGs) could change players' empathic responses to painful situations. However, it remains unclear whether exposure to VVG influences the empathy for pain. In the present study, in terms of the exposure experience to VVG, two groups of participants (18 in VVG group, VG; 17 in non-VVG group, NG) were screened from nearly 200 video game experience questionnaires. And then, the functional magnetic resonance imaging data were recorded when they were viewing painful and non-painful stimuli. The results showed that the perception of others' pain were not significantly different in brain regions between groups, from which we could infer that the desensitization effect of VVGs was overrated.

A Systematic Review of the Impact of Educational Programs on Factors That Affect Nurses' Post-Operative Pain Management for Children.

PubMed

AlReshidi, Nahar; Long, Tony; Darvill, Angela

2018-03-01

Despite extensive research in the international arena into pain and its management, there is, as yet, little research on the topic of pain in children in Saudi Arabia and in the Gulf countries generally. A systematic review was conducted to explore the impact of education programs on factors affecting paediatric nurses' postoperative pain management practice. This was done in order to advise the creation of an educational program for nurses in Saudi Arabia. Knowledge about pain, attitudes towards pain, beliefs about children's pain, perceptions of children's reports of pain, self-efficacy with regard to pain management, and perceptions of barriers to optimal practice were all considered to be relevant factors. The review was restricted to randomized controlled trials and quasi-experimental designs, excluding studies focussed on chronic pain or populations other than solely children. Studies published in English between 2000 and 2016 were identified using CINAHL, MEDLINE, Ovid SP, The Cochrane Library, ProQuest, and Google Scholar databases. Of 499 published studies identified by the search, 14 met the inclusion criteria and were included in the review. There was evidence of educational programs exerting a postive impact on enhancing pediatric nurses' knowledge of pain and modifing their attitudes towards it, but only limited evidence was available about the impact on nurses' beliefs and perceptions of children's reports of pain, nurses' self-efficacy, or barriers to optimal practice. None of the studies was conducted in Saudi Arabia. Studies were needed to address additional aspects of preparedness for effective postperative pain management. Details of educational programs used as experimental intervention must be included in reports.

Best candidates for cognitive treatment of illness perceptions in chronic low back pain: results of a theory-driven predictor study.

PubMed

Siemonsma, Petra C; Stuvie, Ilse; Roorda, Leo D; Vollebregt, Joke A; Lankhorst, Gustaaf J; Lettinga, Ant T

2011-04-01

The aim of this study was to identify treatment-specific predictors of the effectiveness of a method of evidence-based treatment: cognitive treatment of illness perceptions. This study focuses on what treatment works for whom, whereas most prognostic studies focusing on chronic non-specific low back pain rehabilitation aim to reduce the heterogeneity of the population of patients who are suitable for rehabilitation treatment in general. Three treatment-specific predictors were studied in patients with chronic non-specific low back pain receiving cognitive treatment of illness perceptions: a rational approach to problem-solving, discussion skills and verbal skills. Hierarchical linear regression analysis was used to assess their predictive value. Short-term changes in physical activity, measured with the Patient-Specific Functioning List, were the outcome measure for cognitive treatment of illness perceptions effect. A total of 156 patients with chronic non-specific low back pain participated in the study. Rational problem-solving was found to be a significant predictor for the change in physical activity. Discussion skills and verbal skills were non-significant. Rational problem-solving explained 3.9% of the total variance. The rational problem-solving scale results are encouraging, because chronic non-specific low back pain problems are complex by nature and can be influenced by a variety of factors. A minimum score of 44 points on the rational problem-solving scale may assist clinicians in selecting the most appropriate candidates for cognitive treatment of illness perceptions.

Self perceptions as predictors for return to work 2 years after rehabilitation in orthopedic trauma inpatients.

PubMed

Iakova, Maria; Ballabeni, Pierluigi; Erhart, Peter; Seichert, Nikola; Luthi, François; Dériaz, Olivier

2012-12-01

This study aimed to identify self-perception variables which may predict return to work (RTW) in orthopedic trauma patients 2 years after rehabilitation. A prospective cohort investigated 1,207 orthopedic trauma inpatients, hospitalised in rehabilitation, clinics at admission, discharge, and 2 years after discharge. Information on potential predictors was obtained from self administered questionnaires. Multiple logistic regression models were applied. In the final model, a higher likelihood of RTW was predicted by: better general health and lower pain at admission; health and pain improvements during hospitalisation; lower impact of event (IES-R) avoidance behaviour score; higher IES-R hyperarousal score, higher SF-36 mental score and low perceived severity of the injury. RTW is not only predicted by perceived health, pain and severity of the accident at the beginning of a rehabilitation program, but also by the changes in pain and health perceptions observed during hospitalisation.

Fear, Pain, Denial, and Spiritual Experiences in Dying Processes

PubMed Central

Reichmuth, O.; Bueche, D.; Traichel, B.; Mao, M. Schuett; Cerny, T.; Strasser, F.

2017-01-01

Purpose: Approaching death seems to be associated with physiological/spiritual changes. Trajectories including the physical–psychological–social–spiritual dimension have indicated a terminal drop. Existential suffering or deathbed visions describe complex phenomena. However, interrelationships between different constituent factors (e.g., fear and pain, spiritual experiences and altered consciousness) are largely unknown. We lack deeper understanding of patients’ inner processes to which care should respond. In this study, we hypothesized that fear/pain/denial would happen simultaneously and be associated with a transformation of perception from ego-based (pre-transition) to ego-distant perception/consciousness (post-transition) and that spiritual (transcendental) experiences would primarily occur in periods of calmness and post-transition. Parameters for observing transformation of perception (pre-transition, transition itself, and post-transition) were patients’ altered awareness of time/space/body and patients’ altered social connectedness. Method: Two interdisciplinary teams observed 80 dying patients with cancer in palliative units at 2 Swiss cantonal hospitals. We applied participant observation based on semistructured observation protocols, supplemented by the list of analgesic and psychotropic medication. Descriptive statistical analysis and Interpretative Phenomenological Analysis (IPA) were combined. International interdisciplinary experts supported the analysis. Results: Most patients showed at least fear and pain once. Many seemed to have spiritual experiences and to undergo a transformation of perception only partly depending on medication. Line graphs representatively illustrate associations between fear/pain/denial/spiritual experiences and a transformation of perception. No trajectory displayed uninterrupted distress. Many patients seemed to die in peace. Previous near-death or spiritual/mystical experiences may facilitate the dying process. Conclusion: Approaching death seems not only characterized by periods of distress but even more by states beyond fear/pain/denial. PMID:28823175

Recommendations on practice of conditioned pain modulation (CPM) testing.

PubMed

Yarnitsky, D; Bouhassira, D; Drewes, A M; Fillingim, R B; Granot, M; Hansson, P; Landau, R; Marchand, S; Matre, D; Nilsen, K B; Stubhaug, A; Treede, R D; Wilder-Smith, O H G

2015-07-01

Protocols for testing conditioned pain modulation (CPM) vary between different labs/clinics. In order to promote research and clinical application of this tool, we summarize the recommendations of interested researchers consensus meeting regarding the practice of CPM and report of its results. © 2014 European Pain Federation - EFIC®

Pain perception in people with Down syndrome: a synthesis of clinical and experimental research

PubMed Central

McGuire, Brian E.; Defrin, Ruth

2015-01-01

People with an intellectual disability experience both acute and chronic pain with at least the same frequency as the general population. However, considerably less is known about the pain perception of people with Down syndrome. In this review paper, we evaluated the available clinical and experimental evidence. Some experimental studies of acute pain have indicated that pain threshold was higher than normal but only when using a reaction time method to measure pain sensitivity. However, when reaction time is not part of the calculation of the pain threshold, pain sensitivity in people with Down syndrome is in fact lower than normal (more sensitive to pain). Clinical studies of chronic pain have shown that people with an intellectual disability experience chronic pain and within that population, people with Down syndrome also experience chronic pain, but the precise prevalence of chronic pain in Down syndrome has yet to be established. Taken together, the literature suggests that people with Down syndrome experience pain, both acute and chronic, with at least the same frequency as the rest of the population. Furthermore, the evidence suggests that although acute pain expression appears to be delayed, once pain is registered, there appears to be a magnified pain response. We conclude by proposing an agenda for future research in this area. PMID:26283936

Effects of physical activity programmes in the workplace (PAPW) on the perception and intensity of musculoskeletal pain experienced by garment workers.

PubMed

Pereira, Cynara Cristina Domingues Alves; López, Ramón Fabian Alonso; Vilarta, Roberto

2013-01-01

The physical activity programmes in the workplace (PAPW) are applied to minimize the prevalence, incidence and intensity of pain. This study evaluated the perception of pain and quantifies its intensity among garment workers before and after performing a PAPW. We included 61 workers of a clothing company, who were classified randomly into experimental group (n = 44) 28.7 ± 8.8 years old and a control group (n = 17) 27.8 ± 7.4 years (20-43 years). The Trigger Points test questionnaire was used to assess pain perception and quantify its intensity. The PAPW was conducted in 15-minute sessions per day, consisting of stretching exercises (40%), muscular endurance (40%), self-massage relaxation and massage techniques (10%), and group dynamics (10%). The garment workers who participated in the PAPW showed a significant reduction of pain felt in the neck and wrists, and also a reduction in pain intensity in shoulders, arms, fingers and wrists that are most often strained during sewing. Our findings suggest that PAPW that target muscle groups that are more tense in sewing tasks, may be considered by companies for supporting adaptation to the work environment and improving health by reducing muscle and joint pain.

Interprofessional Team's Perception of Care Delivery After Implementation of a Pediatric Pain and Sedation Protocol.

PubMed

Staveski, Sandra L; Wu, May; Tesoro, Tiffany M; Roth, Stephen J; Cisco, Michael J

2017-06-01

Pain and agitation are common experiences of patients in pediatric cardiac intensive care units. Variability in assessments by health care providers, communication, and treatment of pain and agitation creates challenges in management of pain and sedation. To develop guidelines for assessment and treatment of pain, agitation, and delirium in the pediatric cardiac intensive unit in an academic children's hospital and to document the effects of implementation of the guidelines on the interprofessional team's perception of care delivery and team function. Before and after implementation of the guidelines, interprofessional team members were surveyed about the members' perception of analgesia, sedation, and delirium management RESULTS: Members of the interprofessional team felt more comfortable with pain and sedation management after implementation of the guidelines. Team members reported improvements in team communication on patients' comfort. Members thought that important information was less likely to be lost during transfer of care. They also noted that the team carried out comfort management plans and used pharmacological and nonpharmacological therapies better after implementation of the guidelines than they did before implementation. Guidelines for pain and sedation management were associated with perceived improvements in team function and patient care by members of the interprofessional team. ©2017 American Association of Critical-Care Nurses.

Night-shift work increases cold pain perception.

PubMed

Pieh, Christoph; Jank, Robert; Waiß, Christoph; Pfeifer, Christian; Probst, Thomas; Lahmann, Claas; Oberndorfer, Stefan

2018-05-01

Although night-shift work (NSW) is associated with a higher risk for several physical and mental disorders, the impact of NSW on pain perception is still unclear. This study investigates the impact of NSW on cold pain perception considering the impact of mood and sleepiness. Quantitative sensory testing (QST) was performed in healthy night-shift workers. Cold pain threshold as well as tonic cold pain was assessed after one habitual night (T1), after a 12-hour NSW (T2) and after one recovery night (T3). Sleep quality was measured with the Pittsburgh Sleep Quality Index (PSQI) before T1, sleepiness with the Stanford Sleepiness Scale (SSS) and mood with a German short-version of the Profile of Mood States (ASTS) at T1, T2 and T3. Depending on the distribution of the data, ANOVAs or Friedman tests as well as t- or Wilcoxon tests were performed. Nineteen healthy shift-workers (13 females; 29.7 ± 7.5 years old; 8.1 ± 6.6 years in shift work, PSQI: 4.7 ± 2.2) were included. Tonic cold pain showed a significant difference between T1 (48.2 ± 27.5 mm), T2 (61.7 ± 26.6 mm; effect size: Cohen's d=.49; percent change 28%), and T3 (52.1 ± 28.7 mm) on a 0-100 mm Visual Analog Scale (p = 0.007). Cold pain threshold changed from 11.0 ± 7.9 °C (T1) to 14.5 ± 8.8 °C (T2) (p = 0.04), however, an ANOVA comparing T1, T2, and T3 was not significant (p = 0.095). Sleepiness (SSS) and mood (ASTS) changed significantly between T1, T2 and T3 (p-values < 0.01). The change of mood but not of sleepiness correlated with the difference in tonic cold pain from T1 to T2 (R: 0.53; R 2 : 0.29; p = 0.022). NSW increases cold pain perception. The same tonic cold pain stimulus is rated 28% more painful after NSW and normalizes after a recovery night. Increases in cold pain perception due to NSW appear to be more strongly related to changes in mood as compared to changes in sleepiness. Copyright © 2018 Elsevier B.V. All rights reserved.

Fibromyalgia Pain: Options for Coping

MedlinePlus

... to ourselves inside our heads can affect our perception of pain. Turning negative thoughts into positive ones ... org/diseases-conditions/fibromyalgia/in-depth/fibromyalgia-pain/ART-20047867 . Mayo Clinic Footer Legal Conditions and Terms ...

The association of perceived discrimination with low back pain.

PubMed

Edwards, Robert R

2008-10-01

A handful of recent studies have documented perceived discrimination as a correlate of poor physical and mental health status among ethnic and racial minority groups. To date, however, despite a proliferation of research on ethnic disparities in the severity and impact of a number of persistent pain conditions, there have been no reports on associations between perceived discrimination and pain-related symptoms. Using data from a national survey (the National Survey of Midlife Development in the United States; MIDUS), we explore the relationships between perceived discriminatory events and the report of back pain among African-American and white men and women. As expected, African-American participants reported substantially greater perceptions of discrimination than white participants. Moreover, in models that included a variety of physical and mental health variables, episodes of major lifetime discriminatory events were the strongest predictors of back pain report in African-Americans, and perceived day-to-day discrimination was the strongest predictor of back pain report specifically in African-American women. Among white participants, perceptions of discrimination were minimally related or unrelated to back pain. To our knowledge, these are the first data documenting an association between perceived discrimination and report of back pain; the fact that perceptions of discrimination were stronger predictors than physical health variables highlights the potential salience and adverse impact of perceived discrimination in ethnic and racial minority groups.

An investigation into the effects of frequency-modulated transcutaneous electrical nerve stimulation (TENS) on experimentally-induced pressure pain in healthy human participants.

PubMed

Chen, Chih-Chung; Johnson, Mark I

2009-10-01

Frequency-modulated transcutaneous electrical nerve stimulation (TENS) delivers currents that fluctuate between preset boundaries over a fixed period of time. This study compared the effects of constant-frequency TENS and frequency-modulated TENS on blunt pressure pain in healthy human volunteers. Thirty-six participants received constant-frequency TENS (80 pps), frequency-modulated TENS (20 to 100 pps), and placebo (no current) TENS at a strong nonpainful intensity in a randomized cross-over manner. Pain threshold was taken from the forearm using pressure algometry. There were no statistical differences between constant-frequency TENS and frequency-modulated TENS after 20 minutes (OR = 1.54; CI, 0.29, 8.23, P = 1.0). Both constant-frequency TENS and frequency-modulated TENS were superior to placebo TENS (OR = 59.5, P < .001 and OR = 38.5, P < .001, respectively). Frequency-modulated TENS does not influence hypoalgesia to any greater extent than constant-frequency TENS when currents generate a strong nonpainful paraesthesia at the site of pain. The finding that frequency-modulated TENS and constant-frequency TENS were superior to placebo TENS provides further evidence that a strong yet nonpainful TENS intensity is a prerequisite for hypoalgesia. This study provides evidence that TENS, delivered at a strong nonpainful intensity, increases pain threshold to pressure algometry in healthy participants over and above that seen with placebo (no current) TENS. Frequency-modulated TENS does not increase hypoalgesia to any appreciable extent to that seen with constant-frequency TENS.

White Cancer Patients’ Perception of Gender and Ethnic Differences in Pain Experience

PubMed Central

Im, Eun-Ok

2008-01-01

Not considering cancer patients’ own views and experience with pain, especially gender and ethnic differences in their cancer pain experience, was reported to be a major contributor to the miscommunication that frequently results in inadequate cancer pain management. The purpose of this study was to explore white cancer patients’ perception of gender and ethnic differences in pain experience through an online forum. This was a descriptive qualitative study among 29 white cancer patients based on a feminist approach. Nine topics related to cancer pain experience were used. The data were analyzed using thematic analysis: 5 themes were identified. First, the participants perceived that pain accompanies cancer throughout the diagnosis and treatment process. Second, the specific characteristics of the participants’ individual culture and its view of pain and cancer could result in different cancer pain experience even among white cancer patients. Third, the participants complained that women’s pain was not taken seriously by health care providers. Fourth, the participants reported highly individualized pain experience with emotional pain. Finally, the participants wanted to have a control of their own pain management process. Based on the findings, implications for nursing research and practice are proposed. PMID:17135816

Effects of Acupuncture on Sensory Perception: A Systematic Review and Meta-Analysis

PubMed Central

Baeumler, Petra I.; Fleckenstein, Johannes; Takayama, Shin; Simang, Michael; Seki, Takashi; Irnich, Dominik

2014-01-01

Background The effect of acupuncture on sensory perception has never been systematically reviewed; although, studies on acupuncture mechanisms are frequently based on the idea that changes in sensory thresholds reflect its effect on the nervous system. Methods Pubmed, EMBASE and Scopus were screened for studies investigating the effect of acupuncture on thermal or mechanical detection or pain thresholds in humans published in English or German. A meta-analysis of high quality studies was performed. Results Out of 3007 identified articles 85 were included. Sixty five studies showed that acupuncture affects at least one sensory threshold. Most studies assessed the pressure pain threshold of which 80% reported an increase after acupuncture. Significant short- and long-term effects on the pressure pain threshold in pain patients were revealed by two meta-analyses including four and two high quality studies, respectively. In over 60% of studies, acupuncture reduced sensitivity to noxious thermal stimuli, but measuring methods might influence results. Few but consistent data indicate that acupuncture reduces pin-prick like pain but not mechanical detection. Results on thermal detection are heterogeneous. Sensory threshold changes were equally frequent reported after manual acupuncture as after electroacupuncture. Among 48 sham-controlled studies, 25 showed stronger effects on sensory thresholds through verum than through sham acupuncture, but in 9 studies significant threshold changes were also observed after sham acupuncture. Overall, there is a lack of high quality acupuncture studies applying comprehensive assessments of sensory perception. Conclusions Our findings indicate that acupuncture affects sensory perception. Results are most compelling for the pressure pain threshold, especially in pain conditions associated with tenderness. Sham acupuncture can also cause such effects. Future studies should incorporate comprehensive, standardized assessments of sensory profiles in order to fully characterize its effect on sensory perception and to explore the predictive value of sensory profiles for the effectiveness of acupuncture. PMID:25502787

Effects of acupuncture on sensory perception: a systematic review and meta-analysis.

PubMed

Baeumler, Petra I; Fleckenstein, Johannes; Takayama, Shin; Simang, Michael; Seki, Takashi; Irnich, Dominik

2014-01-01

The effect of acupuncture on sensory perception has never been systematically reviewed; although, studies on acupuncture mechanisms are frequently based on the idea that changes in sensory thresholds reflect its effect on the nervous system. Pubmed, EMBASE and Scopus were screened for studies investigating the effect of acupuncture on thermal or mechanical detection or pain thresholds in humans published in English or German. A meta-analysis of high quality studies was performed. Out of 3007 identified articles 85 were included. Sixty five studies showed that acupuncture affects at least one sensory threshold. Most studies assessed the pressure pain threshold of which 80% reported an increase after acupuncture. Significant short- and long-term effects on the pressure pain threshold in pain patients were revealed by two meta-analyses including four and two high quality studies, respectively. In over 60% of studies, acupuncture reduced sensitivity to noxious thermal stimuli, but measuring methods might influence results. Few but consistent data indicate that acupuncture reduces pin-prick like pain but not mechanical detection. Results on thermal detection are heterogeneous. Sensory threshold changes were equally frequent reported after manual acupuncture as after electroacupuncture. Among 48 sham-controlled studies, 25 showed stronger effects on sensory thresholds through verum than through sham acupuncture, but in 9 studies significant threshold changes were also observed after sham acupuncture. Overall, there is a lack of high quality acupuncture studies applying comprehensive assessments of sensory perception. Our findings indicate that acupuncture affects sensory perception. Results are most compelling for the pressure pain threshold, especially in pain conditions associated with tenderness. Sham acupuncture can also cause such effects. Future studies should incorporate comprehensive, standardized assessments of sensory profiles in order to fully characterize its effect on sensory perception and to explore the predictive value of sensory profiles for the effectiveness of acupuncture.

Reticular Formation and Pain: The Past and the Future

PubMed Central

Martins, Isabel; Tavares, Isaura

2017-01-01

The involvement of the reticular formation (RF) in the transmission and modulation of nociceptive information has been extensively studied. The brainstem RF contains several areas which are targeted by spinal cord afferents conveying nociceptive input. The arrival of nociceptive input to the RF may trigger alert reactions which generate a protective/defense reaction to pain. RF neurons located at the medulla oblongata and targeted by ascending nociceptive information are also involved in the control of vital functions that can be affected by pain, namely cardiovascular control. The RF contains centers that belong to the pain modulatory system, namely areas involved in bidirectional balance (decrease or enhancement) of pain responses. It is currently accepted that the imbalance of pain modulation towards pain facilitation accounts for chronic pain. The medullary RF has the peculiarity of harboring areas involved in bidirectional pain control namely by the existence of specific neuronal populations involved in antinociceptive or pronociceptive behavioral responses, namely at the rostroventromedial medulla (RVM) and the caudal ventrolateral medulla (VLM). Furthermore the dorsal reticular nucleus (also known as subnucleus reticularis dorsalis; DRt) may enhance nociceptive responses, through a reverberative circuit established with spinal lamina I neurons and inhibit wide-dynamic range (WDR) neurons of the deep dorsal horn. The components of the triad RVM-VLM-DRt are reciprocally connected and represent a key gateway for top-down pain modulation. The RVM-VLM-DRt triad also represents the neurobiological substrate for the emotional and cognitive modulation of pain, through pathways that involve the periaqueductal gray (PAG)-RVM connection. Collectively, we propose that the RVM-VLM-DRt triad represents a key component of the “dynamic pain connectome” with special features to provide integrated and rapid responses in situations which are life-threatening and involve pain. The new available techniques in neurobiological studies both in animal and human studies are producing new and fascinating data which allow to understand the complex role of the RF in pain modulation and its integration with several body functions and also how the RF accounts for chronic pain. PMID:28725185

Reticular Formation and Pain: The Past and the Future.

PubMed

Martins, Isabel; Tavares, Isaura

2017-01-01

The involvement of the reticular formation (RF) in the transmission and modulation of nociceptive information has been extensively studied. The brainstem RF contains several areas which are targeted by spinal cord afferents conveying nociceptive input. The arrival of nociceptive input to the RF may trigger alert reactions which generate a protective/defense reaction to pain. RF neurons located at the medulla oblongata and targeted by ascending nociceptive information are also involved in the control of vital functions that can be affected by pain, namely cardiovascular control. The RF contains centers that belong to the pain modulatory system, namely areas involved in bidirectional balance (decrease or enhancement) of pain responses. It is currently accepted that the imbalance of pain modulation towards pain facilitation accounts for chronic pain. The medullary RF has the peculiarity of harboring areas involved in bidirectional pain control namely by the existence of specific neuronal populations involved in antinociceptive or pronociceptive behavioral responses, namely at the rostroventromedial medulla (RVM) and the caudal ventrolateral medulla (VLM). Furthermore the dorsal reticular nucleus (also known as subnucleus reticularis dorsalis; DRt) may enhance nociceptive responses, through a reverberative circuit established with spinal lamina I neurons and inhibit wide-dynamic range (WDR) neurons of the deep dorsal horn. The components of the triad RVM-VLM-DRt are reciprocally connected and represent a key gateway for top-down pain modulation. The RVM-VLM-DRt triad also represents the neurobiological substrate for the emotional and cognitive modulation of pain, through pathways that involve the periaqueductal gray (PAG)-RVM connection. Collectively, we propose that the RVM-VLM-DRt triad represents a key component of the "dynamic pain connectome" with special features to provide integrated and rapid responses in situations which are life-threatening and involve pain. The new available techniques in neurobiological studies both in animal and human studies are producing new and fascinating data which allow to understand the complex role of the RF in pain modulation and its integration with several body functions and also how the RF accounts for chronic pain.

Muscle pain perception and sympathetic nerve activity to exercise during opioid modulation

NASA Technical Reports Server (NTRS)

Cook, D. B.; O'Connor, P. J.; Ray, C. A.

2000-01-01

The purpose of this experiment was to examine the effects of the endogenous opioid system on forearm muscle pain and muscle sympathetic nerve activity (MSNA) during dynamic fatiguing exercise. Twelve college-age men (24 +/- 4 yr) performed graded (1-min stages; 30 contractions/min) handgrip to fatigue 1 h after the ingestion of either 60 mg codeine, 50 mg naltrexone, or placebo. Pain (0-10 scale) and exertion (0-10 and 6-20 scales) intensities were measured during the last 15 s of each minute of exercise and every 15 s during recovery. MSNA was measured continuously from the peroneal nerve in the left leg. Pain threshold occurred earlier [1.8 +/- 1, 2. 2 +/- 1, 2.2 +/- 1 J: codeine, naltrexone, and placebo, respectively] and was associated with a lower rating of perceived exertion (RPE) (2.7 +/- 2, 3.6 +/- 2, 3.8 +/- 2: codeine, naltrexone, and placebo, respectively) in the codeine condition compared with either the naltrexone or placebo conditions. There were no main effects (i.e., drugs) or interaction (i.e., drugs x time) for either forearm muscle pain or RPE during exercise [pain: F (2, 22) = 0.69, P = 0.51]. There was no effect of drug on MSNA, heart rate, or blood pressure during baseline, exercise, or recovery. Peak exercise MSNA responses were 21 +/- 1, 21 +/- 2.0, and 21 +/- 2.0 bursts/30 s for codeine, naltrexone, and placebo conditions, respectively. Peak mean arterial pressure responses were 135 +/- 4, 131 +/- 3, and 132 +/- 4 mmHg for codeine, naltrexone, and placebo conditions, respectively. It is concluded that neither 60 mg codeine nor 50 mg naltrexone has an effect on forearm muscle pain, exertion, or MSNA during high- intensity handgrip to fatigue.

Ion channel blockers for the treatment of neuropathic pain.

PubMed

Colombo, Elena; Francisconi, Simona; Faravelli, Laura; Izzo, Emanuela; Pevarello, Paolo

2010-05-01

Neuropathic pain, a severe chronic pain condition characterized by a complex pathophysiology, is a largely unmet medical need. Ion channels, which underlie cell excitability, are heavily implicated in the biological mechanisms that generate and sustain neuropathic pain. This review highlights the biological evidence supporting the involvement of voltage-, proton- and ligand-gated ion channels in the neuropathic pain setting. Ion channel modulators at different research or development stages are reviewed and referenced. Ion channel modulation is one of the main avenues to achieve novel, improved neuropathic pain treatments. Voltage-gated sodium and calcium channel and glutamate receptor modulators are likely to produce new, improved agents in the future. Rationally targeting subtypes of known ion channels, tackling recently discovered ion channel targets or combining drugs with different mechanism of action will be primary sources of new drugs in the longer term.

Does experimental pain affect auditory processing of speech-relevant signals? A study in healthy young adults.

PubMed

Sapir, Shimon; Pud, Dorit

2008-01-01

To assess the effect of tonic pain stimulation on auditory processing of speech-relevant acoustic signals in healthy pain-free volunteers. Sixty university students, randomly assigned to either a thermal pain stimulation (46 degrees C/6 min) group (PS) or no pain stimulation group (NPS), performed a rate change detection task (RCDT) involving sinusoidally frequency-modulated vowel-like signals. Task difficulty was manipulated by changing the rate of the modulated signals (henceforth rate). Perceived pain intensity was evaluated using a visual analog scale (VAS) (0-100). Mean pain rating was approximately 33 in the PS group and approximately 3 in the NPS group. Pain stimulation was associated with poorer performance on the RCDT, but this trend was not statistically significant. Performance worsened with increasing rate of signal modulation in both groups (p < 0.0001), with no pain by rate interaction. The present findings indicate a trend whereby mild or moderate pain appears to affect auditory processing of speech-relevant acoustic signals. This trend, however, was not statistically significant. It is possible that more intense pain would yield more pronounced (deleterious) effects on auditory processing, but this needs to be verified empirically.

Pain and other symptoms of CRPS can be increased by ambiguous visual stimuli--an exploratory study.

PubMed

Hall, Jane; Harrison, Simon; Cohen, Helen; McCabe, Candida S; Harris, N; Blake, David R

2011-01-01

Visual disturbance, visuo-spatial difficulties, and exacerbations of pain associated with these, have been reported by some patients with Complex Regional Pain Syndrome (CRPS). We investigated the hypothesis that some visual stimuli (i.e. those which produce ambiguous perceptions) can induce pain and other somatic sensations in people with CRPS. Thirty patients with CRPS, 33 with rheumatology conditions and 45 healthy controls viewed two images: a bistable spatial image and a control image. For each image participants recorded the frequency of percept change in 1 min and reported any changes in somatosensation. 73% of patients with CRPS reported increases in pain and/or sensory disturbances including changes in perception of the affected limb, temperature and weight changes and feelings of disorientation after viewing the bistable image. Additionally, 13% of the CRPS group responded with striking worsening of their symptoms which necessitated task cessation. Subjects in the control groups did not report pain increases or somatic sensations. It is possible to worsen the pain suffered in CRPS, and to produce other somatic sensations, by means of a visual stimulus alone. This is a newly described finding. As a clinical and research tool, the experimental method provides a means to generate and exacerbate somaesthetic disturbances, including pain, without moving the affected limb and causing nociceptive interference. This may be particularly useful for brain imaging studies. Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.

Short-term pre- and post-operative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception.

PubMed

Cao, Jing; Wang, Po-Kai; Tiwari, Vinod; Liang, Lingli; Lutz, Brianna Marie; Shieh, Kun-Ruey; Zang, Wei-Dong; Kaufman, Andrew G; Bekker, Alex; Gao, Xiao-Qun; Tao, Yuan-Xiang

2015-12-02

Chronic stress has been reported to increase basal pain sensitivity and/or exacerbate existing persistent pain. However, most surgical patients have normal physiological and psychological health status such as normal pain perception before surgery although they do experience short-term stress during pre- and post-operative periods. Whether or not this short-term stress affects persistent postsurgical pain is unclear. In this study, we showed that pre- or post-surgical exposure to immobilization 6 h daily for three consecutive days did not change basal responses to mechanical, thermal, or cold stimuli or peak levels of incision-induced hypersensitivity to these stimuli; however, immobilization did prolong the duration of incision-induced hypersensitivity in both male and female rats. These phenomena were also observed in post-surgical exposure to forced swimming 25 min daily for 3 consecutive days. Short-term stress induced by immobilization was demonstrated by an elevation in the level of serum corticosterone, an increase in swim immobility, and a decrease in sucrose consumption. Blocking this short-term stress via intrathecal administration of a selective glucocorticoid receptor antagonist, RU38486, or bilateral adrenalectomy significantly attenuated the prolongation of incision-induced hypersensitivity to mechanical, thermal, and cold stimuli. Our results indicate that short-term stress during the pre- or post-operative period delays postoperative pain recovery although it does not affect basal pain perception. Prevention of short-term stress may facilitate patients' recovery from postoperative pain.

The effect of chemically induced colitis, psychological stress and their combination on visceral pain in female Wistar rats.

PubMed

Deiteren, Annemie; Vermeulen, Wim; Moreels, Tom G; Pelckmans, Paul A; De Man, Joris G; De Winter, Benedicte Y

2014-09-01

Visceral sensitivity is of pathophysiological importance in abdominal pain disorders and can be modulated by inflammation and stress. However, it is unclear whether inflammation and stress alter visceral perception independently of each other or in conjunction through neuroendocrine interactions. Therefore, we compared the short- and long-term effects of experimental colitis and water avoidance stress (WAS), alone or in combination, on visceral sensitivity in female Wistar rats. Colitis was induced by trinitrobenzene sulfonic acid (TNBS) and colonoscopically confirmed. During WAS, rats were placed on a platform surrounded by water for 1 h. Visceral sensitivity was assessed by quantifying the visceromotor responses (VMRs) to colorectal distension. Activation of the hypothalamic-pituitary-adrenal axis was determined by measuring serum corticosterone in a separate protocol. TNBS instillation resulted in overt colitis, associated with significant visceral hypersensitivity during the acute inflammatory phase (3 days post-TNBS; n = 8/group); after colitis had subsided (28 days post-TNBS), hypersensitivity was resolved (n = 4-8/group). Single WAS was associated with increased VMRs of a magnitude comparable to acute TNBS-induced hypersensitivity (n = 8/group). However, after repetitive WAS no significant hypersensitivity was present (n = 8/group). No additive effect of colitis and stress was seen on visceral pain perception (n = 6-8/group). Corticosterone levels were only increased in acute TNBS-colitis, acute WAS and their combination. To conclude, both colitis and stress successfully induced short-term visceral hypersensitivity and activated the hypothalamic-pituitary-adrenal axis, but long-term effects were absent. In addition, our current findings do not support an additive effect of colitis and stress on visceral sensitivity in female Wistar rats.

Pharmacogenetics in obstetric anesthesia.

PubMed

Landau, Ruth; Kraft, John C

2010-06-01

Genomic research in pain, anesthesia and analgesia generated some hope that pharmacogenetics may guide anesthesiologists to provide effective medicine in a 'tailored' manner. Within the field of obstetric anesthesia, relatively few studies have evaluated the effect of polymorphisms on the perception of labor or postcesarean pain or the response to analgesics for childbirth. Because of the multifactorial nature of labor and delivery pain and particularly challenging clinical context, many consider that 'titration of drugs to the desired effect works just fine'. With recent evidence highlighting an association between severe postdelivery pain and persistent pain, early recognition of an increased susceptibility for acute pain has become particularly relevant. Neuraxial labor analgesia is influenced by a common polymorphism of the mu-opioid receptor gene. This polymorphism also affects the analgesic response to systemic opioids for postcesarean pain and other types of surgeries. Finally, the risk for persistent pain after cesarean deliveries may be associated with a certain genetic profile. Although still premature to anticipate clinical implications and a change in practice based on these recent discoveries, genetic variability clearly appears to affect pain perception, response to analgesics and predisposition for the development of chronic pain.

Cervical joint position sense in neck pain. Immediate effects of muscle vibration versus mental training interventions: a RCT.

PubMed

Beinert, K; Preiss, S; Huber, M; Taube, W

2015-12-01

Impaired cervical joint position sense is a feature of chronic neck pain and is commonly argued to rely on abnormal cervical input. If true, muscle vibration, altering afferent input, but not mental interventions, should have an effect on head repositioning acuity and neck pain perception. The aim of the present study was to determine the short-term effects of neck muscle vibration, motor imagery, and action observation on cervical joint position sense and pressure pain threshold in people with chronic neck pain. Forty-five blinded participants with neck pain received concealed allocation and were randomized in three treatment groups. A blinded assessor performed pre- and post-test measurement. Patients were recruited from secondary outpatient clinics in the southwest of Germany. Chronic, non specific neck pain patients without arm pain were recruited for this study. A single intervention session of 5 minutes was delivered to each blinded participant. Patients were either allocated to one of the following three interventions: (1) neck muscle vibration; (2) motor imagery; (3) action observation. Primary outcomes were cervical joint position sense acuity and pressure pain threshold. Repeated measures ANOVAs were used to evaluate differences between groups and subjects. Repositioning acuity displayed significant time effects for vibration, motor imagery, and action observation (all P<0.05), but revealed no time*group effect. Pressure pain threshold demonstrated a time*group effect (P=0.042) as only vibration significantly increased pressure pain threshold (P=0.01). Although motor imagery and action observation did not modulate proprioceptive, afferent input, they nevertheless improved cervical joint position sense acuity. This indicates that, against the common opinion, changes in proprioceptive input are not prerequisite to improve joint repositioning performance. However, the short-term applications of these cognitive treatments had no effect on pressure pain thresholds, whereas vibration reduced pressure pain thresholds. This implies different underlying mechanisms after vibration and mental training. Mental interventions were effective in improving cervical joint position sense and are easy to integrate in rehabilitation regimes. Neck muscle vibration is effective in improving cervical joint position sense and pressure pain thresholds within 5 minutes of application.

Spinal Cord Stimulation (SCS) and Functional Magnetic Resonance Imaging (fMRI): Modulation of Cortical Connectivity With Therapeutic SCS.

PubMed

Deogaonkar, Milind; Sharma, Mayur; Oluigbo, Chima; Nielson, Dylan M; Yang, Xiangyu; Vera-Portocarrero, Louis; Molnar, Gregory F; Abduljalil, Amir; Sederberg, Per B; Knopp, Michael; Rezai, Ali R

2016-02-01

The neurophysiological basis of pain relief due to spinal cord stimulation (SCS) and the related cortical processing of sensory information are not completely understood. The aim of this study was to use resting state functional magnetic resonance imaging (rs-fMRI) to detect changes in cortical networks and cortical processing related to the stimulator-induced pain relief. Ten patients with complex regional pain syndrome (CRPS) or neuropathic leg pain underwent thoracic epidural spinal cord stimulator implantation. Stimulation parameters associated with "optimal" pain reduction were evaluated prior to imaging studies. Rs-fMRI was obtained on a 3 Tesla, Philips Achieva MRI. Rs-fMRI was performed with stimulator off (300TRs) and stimulator at optimum (Opt, 300 TRs) pain relief settings. Seed-based analysis of the resting state functional connectivity was conducted using seeds in regions established as participating in pain networks or in the default mode network (DMN) in addition to the network analysis. NCUT (normalized cut) parcellation was used to generate 98 cortical and subcortical regions of interest in order to expand our analysis of changes in functional connections to the entire brain. We corrected for multiple comparisons by limiting the false discovery rate to 5%. Significant differences in resting state connectivity between SCS off and optimal state were seen between several regions related to pain perception, including the left frontal insula, right primary and secondary somatosensory cortices, as well as in regions involved in the DMN, such as the precuneus. In examining changes in connectivity across the entire brain, we found decreased connection strength between somatosensory and limbic areas and increased connection strength between somatosensory and DMN with optimal SCS resulting in pain relief. This suggests that pain relief from SCS may be reducing negative emotional processing associated with pain, allowing somatosensory areas to become more integrated into default mode activity. SCS reduces the affective component of pain resulting in optimal pain relief. Study shows a decreased connectivity between somatosensory and limbic areas associated with optimal pain relief due to SCS. © 2015 International Neuromodulation Society.

Neuropeptides and Microglial Activation in Inflammation, Pain, and Neurodegenerative Diseases

PubMed Central

2017-01-01

Microglial cells are responsible for immune surveillance within the CNS. They respond to noxious stimuli by releasing inflammatory mediators and mounting an effective inflammatory response. This is followed by release of anti-inflammatory mediators and resolution of the inflammatory response. Alterations to this delicate process may lead to tissue damage, neuroinflammation, and neurodegeneration. Chronic pain, such as inflammatory or neuropathic pain, is accompanied by neuroimmune activation, and the role of glial cells in the initiation and maintenance of chronic pain has been the subject of increasing research over the last two decades. Neuropeptides are small amino acidic molecules with the ability to regulate neuronal activity and thereby affect various functions such as thermoregulation, reproductive behavior, food and water intake, and circadian rhythms. Neuropeptides can also affect inflammatory responses and pain sensitivity by modulating the activity of glial cells. The last decade has witnessed growing interest in the study of microglial activation and its modulation by neuropeptides in the hope of developing new therapeutics for treating neurodegenerative diseases and chronic pain. This review summarizes the current literature on the way in which several neuropeptides modulate microglial activity and response to tissue damage and how this modulation may affect pain sensitivity. PMID:28154473

Functional dissociation of stimulus intensity encoding and predictive coding of pain in the insula

PubMed Central

Geuter, Stephan; Boll, Sabrina; Eippert, Falk; Büchel, Christian

2017-01-01

The computational principles by which the brain creates a painful experience from nociception are still unknown. Classic theories suggest that cortical regions either reflect stimulus intensity or additive effects of intensity and expectations, respectively. By contrast, predictive coding theories provide a unified framework explaining how perception is shaped by the integration of beliefs about the world with mismatches resulting from the comparison of these beliefs against sensory input. Using functional magnetic resonance imaging during a probabilistic heat pain paradigm, we investigated which computations underlie pain perception. Skin conductance, pupil dilation, and anterior insula responses to cued pain stimuli strictly followed the response patterns hypothesized by the predictive coding model, whereas posterior insula encoded stimulus intensity. This novel functional dissociation of pain processing within the insula together with previously observed alterations in chronic pain offer a novel interpretation of aberrant pain processing as disturbed weighting of predictions and prediction errors. DOI: http://dx.doi.org/10.7554/eLife.24770.001 PMID:28524817

CD26 modulates nociception in mice via its dipeptidyl-peptidase IV activity.

PubMed

Guieu, Regis; Fenouillet, Emmanuel; Devaux, Christiane; Fajloun, Ziad; Carrega, Louis; Sabatier, Jean-Marc; Sauze, Nicole; Marguet, Didier

2006-01-30

CD26 is a multifunctional cell surface glycoprotein expressed by T and B cells. It exhibits a dipeptidyl-peptidase activity (DPP-IV) that cleaves the penultimate proline from the N-terminus of polypeptides, thereby regulating their activity and concentration. Using CD26-/- mice resulting from targeted inactivation of the gene, we examined the consequences of a DPP-IV defect on behavioural response to nociceptive stimuli and concentration of the pain modulator peptides substance P (SP) and endomorphin 2, two DPP-IV substrates. CD26 inactivation induced a three-fold decrease in circulating endopeptidase activity while that found in brain extracts was normal, albeit very weak. CD26-/- mice had high SP concentrations in plasma (3.4+/-1 pg/ml versus 1.5+/-0.3 pg/ml, P<10(-3)) but not in brain extracts (35+/-12 pg/ml versus 32+/-9 pg/ml, P>0.05). Endomorphin-2 levels in the two groups were in the same range for plasma and brain extracts. CD26-/- mice displayed short latencies to nociceptive stimuli (hot plate test: 6.6+/-1.2 s versus 8.6+/-1.5 s, P<10(-4); tail pinch test: 3.1+/-0.6 s versus 4.2+/-0.8 s, P<10(-3)). Administration of an SP (NK1) receptor antagonist or DPP-IV to CD26-/- mice normalised latencies. DPP-IV inhibitors decreased latencies only in CD26+/+ mice. Our observations represent the first fundamental evidence showing that DPP-IV influences pain perception via modulation of the peripheral SP concentration. Our work also highlights the role of peripheral NK1 receptors in nociception.

Pain in context: Cues predicting a reward decrease fear of movement related pain and avoidance behavior.

PubMed

Claes, Nathalie; Vlaeyen, Johan W S; Crombez, Geert

2016-09-01

Previous research shows that goal-directed behavior might be modulated by cues that predict (dis)similar outcomes. However, the literature investigating this modulation with pain outcomes is scarce. Therefore, this experiment investigated whether environmental cues predicting pain or reward modulate defensive pain responding. Forty-eight healthy participants completed a joystick movement task with two different movement orientations. Performing one movement was associated with a painful stimulus, whereas performance of another movement was associated with reward, i.e. lottery tickets. In a subsequent task, participants learned to associate three different cues withpain, reward, or neither of the two. Next, these cues were integrated in the movement task. This study demonstrates that in general, aversive cues enhance and appetitive cues reduce pain-related fear. Furthermore, we found that incongruence between the outcomes predicted by the movement and the cue results in more oscillatory behavior, i.e., participants were more willing to perform a painful movement when a cue predicting reward was simultaneously presented, and vice versa. Similarly, when given a choice, participants preferred to perform the reward movement, unless there was an incongruence between the outcomes predicted by the movements and cues. Taken together, these results provide experimental evidence that environmental cues are capable of modulating pain-related fear and avoidance behavior. Copyright © 2016 Elsevier Ltd. All rights reserved.

Subliminal stimuli modulate somatosensory perception rhythmically and provide evidence for discrete perception.

PubMed

Baumgarten, Thomas J; Königs, Sara; Schnitzler, Alfons; Lange, Joachim

2017-03-09

Despite being experienced as continuous, there is an ongoing debate if perception is an intrinsically discrete process, with incoming sensory information treated as a succession of single perceptual cycles. Here, we provide causal evidence that somatosensory perception is composed of discrete perceptual cycles. We used in humans an electrotactile temporal discrimination task preceded by a subliminal (i.e., below perceptual threshold) stimulus. Although not consciously perceived, subliminal stimuli are known to elicit neuronal activity in early sensory areas and modulate the phase of ongoing neuronal oscillations. We hypothesized that the subliminal stimulus indirectly, but systematically modulates the ongoing oscillatory phase in S1, thereby rhythmically shaping perception. The present results confirm that, without being consciously perceived, the subliminal stimulus critically influenced perception in the discrimination task. Importantly, perception was modulated rhythmically, in cycles corresponding to the beta-band (13-18 Hz). This can be compellingly explained by a model of discrete perceptual cycles.

Text neck and neck pain in 18-21-year-old young adults.

PubMed

Damasceno, Gerson Moreira; Ferreira, Arthur Sá; Nogueira, Leandro Alberto Calazans; Reis, Felipe José Jandre; Andrade, Igor Caio Santana; Meziat-Filho, Ney

2018-06-01

The aim of this study was to investigate whether there is an association between text neck and neck pain in young adults. Observational cross-sectional study with 150 18-21-year-old young adults from a public high school in the state of Rio de Janeiro was performed. In the self-report questionnaire, the participants answered questions on sociodemographic factors, anthropometric factors, time spent texting or playing on a mobile phone, visual impairments, and concern with the body posture. The neck posture was assessed by participants' self-perception and physiotherapists' judgment during a mobile phone texting message task. The Young Spine Questionnaire was used to evaluate the neck pain. Four multivariate logistic regression models were fitted to investigate the association between neck posture during mobile phone texting and neck pain, considering potential confounding factors. There is no association between neck posture, assessed by self-perception, and neck pain (OR = 1.66, p = 0.29), nor between neck posture, assessed by physiotherapists' judgment, and neck pain (OR = 1.23, p = 0.61). There was also no association between neck posture, assessed by self-perception, and frequency of neck pain (OR = 2.19, p = 0.09), nor between neck posture, assessed by physiotherapists' judgment, and frequency of neck pain (OR = 1.17, p = 0.68). This study did not show an association between text neck and neck pain in 18-21-year-old young adults. The findings challenge the belief that neck posture during mobile phone texting is associated to the growing prevalence of neck pain.

A pilot study of the tolerability and effects of high-definition transcranial direct current stimulation (HD-tDCS) on pain perception.

PubMed

Borckardt, Jeffrey J; Bikson, Marom; Frohman, Heather; Reeves, Scott T; Datta, Abhishek; Bansal, Varun; Madan, Alok; Barth, Kelly; George, Mark S

2012-02-01

Several brain stimulation technologies are beginning to evidence promise as pain treatments. However, traditional versions of 1 specific technique, transcranial direct current stimulation (tDCS), stimulate broad regions of cortex with poor spatial precision. A new tDCS design, called high definition tDCS (HD-tDCS), allows for focal delivery of the charge to discrete regions of the cortex. We sought to preliminarily test the safety and tolerability of the HD-tDCS technique as well as to evaluate whether HD-tDCS over the motor cortex would decrease pain and sensory experience. Twenty-four healthy adult volunteers underwent quantitative sensory testing before and after 20 minutes of real (n = 13) or sham (n = 11) 2 mA HD-tDCS over the motor cortex. No adverse events occurred and no side effects were reported. Real HD-tDCS was associated with significantly decreased heat and cold sensory thresholds, decreased thermal wind-up pain, and a marginal analgesic effect for cold pain thresholds. No significant effects were observed for mechanical pain thresholds or heat pain thresholds. HD-tDCS appears well tolerated, and produced changes in underlying cortex that are associated with changes in pain perception. Future studies are warranted to investigate HD-tDCS in other applications, and to examine further its potential to affect pain perception. This article presents preliminary tolerability and efficacy data for a new focal brain stimulation technique called high definition transcranial direct current stimulation. This technique may have applications in the management of pain. Copyright © 2012. Published by Elsevier Inc.

A snap shot of patients' recall, attitudes, and perceptions of their pain contracts from a family medicine resident outpatient clinic.

PubMed

Bahniwal, Robinder; Sell, Jarrett; Waheed, Abdul

Determine patient recall, attitudes, and perceptions of their pain contract in a family medicine resident out-patient clinic. A cross-sectional study design using a telephone survey to all eligible subjects who signed a hardcopy pain contract from August 29, 2014 to May 19, 2016 at a resident outpatient clinic. Penn State Hershey Family and Community Medicine Residency clinic. All patients who signed a hardcopy pain contract at the practice site who met specific inclusion criteria. What proportions of items are remembered from the standardized Penn State Hershey pain contract and does recall vary with time of contract signing. Patient attitudes and perceptions of their pain contract. Ninety-five percent of patients recalled agreeing to random urine drug screens (UDS) and 60 percent recalled they were not to receive prescriptions from another provider unless approved by their practice site. The recall rate for the remaining 33 items in the contract ranged from 0 percent to 20 percent. The highest recall rate was for contracts signed between 0-3 months. Patient feedback regarding the pain contract was recorded and while five were positive or neutral, 15 patients recorded negative attitudes toward the process, the physician, and/or the UDS. This study highlights limited recall and negative patient attitudes toward the pain contract. Considering the public health concerns with regard to the current opioid epidemic in the United States, additional training of providers, redesign of pain contracts and new models for informing patients about safe chronic pain management may be warranted.

Attractiveness, diagnostic ambiguity, and disability cues impact perceptions of women with pain.

PubMed

LaChapelle, Diane L; Lavoie, Susan; Higgins, Nancy C; Hadjistavropoulos, Thomas

2014-05-01

This experimental study investigated how physical attractiveness, disability cue, and diagnostic ambiguity stereotypes impact perceptions of a patient's pain/disability and personality. After viewing photographs of women pictured with or without a cane, accompanied by descriptions of the women's diagnosis (fibromyalgia or rheumatoid arthritis), 147 university students rated the women's pain/disability and personality. Analyses revealed that more attractive women received lower ratings on pain/disability and higher ratings (more positive) on personality. Moreover, those pictured with a disability cue got higher ratings on both pain/disability and personality, and those with medical evidence of pathology (less ambiguity) got higher ratings on pain/disability and lower ratings on personality. Examination of the 3 stereotypes in a single study enabled an evaluation of their interactions. An Attractiveness × Disability Cue × Diagnostic Ambiguity interaction for ratings of pain/disability revealed that the presence of both medical evidence and a disability cue were needed to override the strong "beautiful is healthy" stereotype. Significant 2-way interactions for ratings of personality indicated that the impact of the disability stereotype tends to be overshadowed by the attractiveness stereotype. The results indicate that these stereotypes have a large effect on perceptions of women with chronic pain and that attractiveness, a contextual variable unrelated to the pain experience, exerts an even stronger effect when there is less objective information available. This could have clinical ramifications for assessment and treatment of patients with chronic pain, which often occurs in the absence of "objective" medical evidence or any external cues of disability. (c) 2014 APA, all rights reserved.

Nonpainful wide-area compression inhibits experimental pain.

PubMed

Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena

2016-09-01

Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM.

A common pronociceptive pain modulation profile typifying subgroups of chronic pelvic pain syndromes is interrelated with enhanced clinical pain.

PubMed

Grinberg, Keren; Granot, Michal; Lowenstein, Lior; Abramov, Liora; Weissman-Fogel, Irit

2017-06-01

Provoked vestibulodynia (PVD) and painful bladder syndrome (PBS), subgroups of chronic pelvic pain syndromes (CPPS), are considered to share common biophysiological peripheral mechanisms. In addition, indications of a pronociceptive pain profile coexisting with psychological vulnerability suggest common dysfunctional pain processing and pain modulation in these 2 subgroups of CPPS. We therefore aimed at comparing the pain profile and psychological traits of patients with PVD and PBS to see whether the pain profile contributes to intersubject variability of clinical pain symptoms. Patients with PVD (n = 18) and PBS (n = 21) were compared with healthy controls (n = 20) in their responses to (1) pain psychophysical tests applied to both referred (suprapubis) and remote (hand) body areas and (2) pain-related psychological factors (pain catastrophizing, depression, anxiety, and somatization). We found a similar pronociceptive pain profile in the 2 subgroups of CPPS-enhanced facilitation (ie, hyperalgesia in the referred body area [P < 0.001]) and inefficient inhibition (ie, reduced conditioned pain modulation [P < 0.001] that were associated with both enhanced pain ratings evoked during trigger point examination [P < 0.037]) and higher Brief Pain Inventory ratings (P = 0.002). The latter was also correlated with pain catastrophizing (r = 0.504, P = 0.001) and depression symptoms (r = 0.361, P = 0.024). The findings suggest common mechanisms underlying a dysfunctional nociceptive system in both PVD and PBS. The intersubject variability in the level of dysfunction and its association with disease severity recommends a personalized pain treatment that may alleviate daily pain and dysfunction in patients with CPPS.

Task modulations of racial bias in neural responses to others' suffering.

PubMed

Sheng, Feng; Liu, Qiang; Li, Hong; Fang, Fang; Han, Shihui

2014-03-01

Recent event related brain potential research observed a greater frontal activity to pain expressions of racial in-group than out-group members and such racial bias in neural responses to others' suffering was modulated by task demands that emphasize race identity or painful feeling. However, as pain expressions activate multiple brain regions in the pain matrix, it remains unclear which part of the neural circuit in response to others' suffering undergoes modulations by task demands. We scanned Chinese adults, using functional MRI, while they categorized Asian and Caucasian faces with pain or neutral expressions in terms of race or identified painful feelings of each individual face. We found that pain vs. neutral expressions of Asian but not Caucasian faces activated the anterior cingulate (ACC) and anterior insular (AI) activity during race judgments. However, pain compared to race judgments increased ACC and AI activity to pain expressions of Caucasian but not Asian faces. Moreover, race judgments induced increased activity in the dorsal medial prefrontal cortex whereas pain judgments increased activity in the bilateral temporoparietal junction. The results suggest that task demands emphasizing an individual's painful feeling increase ACC/AI activities to pain expressions of racial out-group members and reduce the racial bias in empathic neural responses. © 2013.

Reduced Pain Sensation and Reduced BOLD Signal in Parietofrontal Networks during Religious Prayer

PubMed Central

Elmholdt, Else-Marie; Skewes, Joshua; Dietz, Martin; Møller, Arne; Jensen, Martin S.; Roepstorff, Andreas; Wiech, Katja; Jensen, Troels S.

2017-01-01

Previous studies suggest that religious prayer can alter the experience of pain via expectation mechanisms. While brain processes related to other types of top-down modulation of pain have been studied extensively, no research has been conducted on the potential effects of active religious coping. Here, we aimed at investigating the neural mechanisms during pain modulation by prayer and their dependency on the opioidergic system. Twenty-eight devout Protestants performed religious prayer and a secular contrast prayer during painful electrical stimulation in two fMRI sessions. Naloxone or saline was administered prior to scanning. Results show that pain intensity was reduced by 11% and pain unpleasantness by 26% during religious prayer compared to secular prayer. Expectancy predicted large amounts (70–89%) of the variance in pain intensity. Neuroimaging results revealed reduced neural activity during religious prayer in a large parietofrontal network relative to the secular condition. Naloxone had no significant effect on ratings or neural activity. Our results thus indicate that, under these conditions, pain modulation by prayer is not opioid-dependent. Further studies should employ an optimized design to explore whether reduced engagement of the frontoparietal system could indicate that prayer may attenuate pain through a reduction in processing of pain stimulus saliency and prefrontal control rather than through known descending pain inhibitory systems. PMID:28701940

Reduced Pain Sensation and Reduced BOLD Signal in Parietofrontal Networks during Religious Prayer.

PubMed

Elmholdt, Else-Marie; Skewes, Joshua; Dietz, Martin; Møller, Arne; Jensen, Martin S; Roepstorff, Andreas; Wiech, Katja; Jensen, Troels S

2017-01-01

Previous studies suggest that religious prayer can alter the experience of pain via expectation mechanisms. While brain processes related to other types of top-down modulation of pain have been studied extensively, no research has been conducted on the potential effects of active religious coping. Here, we aimed at investigating the neural mechanisms during pain modulation by prayer and their dependency on the opioidergic system. Twenty-eight devout Protestants performed religious prayer and a secular contrast prayer during painful electrical stimulation in two fMRI sessions. Naloxone or saline was administered prior to scanning. Results show that pain intensity was reduced by 11% and pain unpleasantness by 26% during religious prayer compared to secular prayer. Expectancy predicted large amounts (70-89%) of the variance in pain intensity. Neuroimaging results revealed reduced neural activity during religious prayer in a large parietofrontal network relative to the secular condition. Naloxone had no significant effect on ratings or neural activity. Our results thus indicate that, under these conditions, pain modulation by prayer is not opioid-dependent. Further studies should employ an optimized design to explore whether reduced engagement of the frontoparietal system could indicate that prayer may attenuate pain through a reduction in processing of pain stimulus saliency and prefrontal control rather than through known descending pain inhibitory systems.

Nociceptive transmission and modulation via P2X receptors in central pain syndrome.

PubMed

Kuan, Yung-Hui; Shyu, Bai-Chuang

2016-05-26

Painful sensations are some of the most frequent complaints of patients who are admitted to local medical clinics. Persistent pain varies according to its causes, often resulting from local tissue damage or inflammation. Central somatosensory pathway lesions that are not adequately relieved can consequently cause central pain syndrome or central neuropathic pain. Research on the molecular mechanisms that underlie this pathogenesis is important for treating such pain. To date, evidence suggests the involvement of ion channels, including adenosine triphosphate (ATP)-gated cation channel P2X receptors, in central nervous system pain transmission and persistent modulation upon and following the occurrence of neuropathic pain. Several P2X receptor subtypes, including P2X2, P2X3, P2X4, and P2X7, have been shown to play diverse roles in the pathogenesis of central pain including the mediation of fast transmission in the peripheral nervous system and modulation of neuronal activity in the central nervous system. This review article highlights the role of the P2X family of ATP receptors in the pathogenesis of central neuropathic pain and pain transmission. We discuss basic research that may be translated to clinical application, suggesting that P2X receptors may be treatment targets for central pain syndrome.

Part-time, e-learning interprofessional pain management education for the primary and community care setting.

PubMed

Jenkins, M Sue; Bean, W Geinor; Luke, Karl

2014-02-01

Chronic pain is a long-term condition, which has a major impact on patients, carers and the health service. Despite the Chief Medical Officer setting chronic pain and its management as a national priority in 2008, the utilisation of health services by patients with long-term conditions is increasing, people with pain-related problems are not seen early enough and pain-related attendances to accident and emergency departments is increasing. Early assessment with appropriate evidence-based intervention and early recognition of when to refer to specialist and specialised services is key to addressing the growing numbers suffering with chronic pain. Pain education is recommended in many guidelines, as part of the process to address pain in these issues. Cardiff University validated an e-learning, master's level pain management module for healthcare professionals working in primary and community care. The learning outcomes revolve around robust early assessment and management of chronic pain in primary and community care and the knowledge when to refer on. The module focuses on the biopsychosocial aspects of pain and its management, using a blog as an online case study assessment for learners to demonstrate their knowledge, understanding and application to practice. The module has resulted in learners developing evidence-based recommendations, for pain management in clinical practice.

Effect of intraoperative analgesia on children's pain perception during recovery after painful dental procedures performed under general anaesthesia.

PubMed

El Batawi, H Y

2015-02-01

To investigate the possible effect of intraoperative analgesia, namely diclofenac sodium compared to acetaminophen on post-recovery pain perception in children undergoing painful dental procedures under general anaesthesia. A double-blind randomised clinical trial. A sample of 180 consecutive cases of children undergoing full dental rehabilitation under general anaesthesia in a private hospital in Saudi Arabia during 2013 was divided into three groups (60 children each) according to the analgesic used prior to extubation. Group A, children had diclofenac sodium suppository. Group B, children received acetaminophen suppository and Group C, the control group. Using an authenticated Arabic version of the Wong and Baker faces Pain assessment Scale, patients were asked to choose the face that suits best the pain he/she is suffering. Data were collected and recorded for statistical analysis. Student's t test was used for comparison of sample means. A preliminary F test to compare sample variances was carried out to determine the appropriate t test variant to be used. A "p" value less than 0.05 was considered significant. More than 93% of children had post-operative pain in varying degrees. High statistical significance was observed between children in groups A and B compared to control group C with the later scoring high pain perception. Diclofenac showed higher potency in multiple painful procedures, while the statistical difference was not significant in children with three or less painful dental procedures. Diclophenac sodium is more potent than acetaminophen, especially for multiple pain-provoking or traumatic procedures. A timely use of NSAID analgesia just before extubation helps provide adequate coverage during recovery. Peri-operative analgesia is to be recommended as an essential treatment adjunct for child dental rehabilitation under general anaesthesia.

[The phenomenon of pain in the history of music – observations of neurobiological mechanisms of pain and its expressions in western music].

PubMed

Gasenzer, E R; Neugebauer, E A M

2014-12-01

Purpose of this essay is to provide a historical overview how music has dealt with the emotion and sensation of pain, as well as an overview over the more recent medical research into the relationship of music and pain. Since the beginnings of western music humans have put their emotions into musical sounds. During the baroque era, composers developed musical styles that expressed human emotions and our experiences of nature. In some compositions, like in operas, we find musical representations of pain. During Romanticism artists began to intrude into the soul of their audience. New expressive harmonies and styles touch the soul and the consciousness of the listener. With the inception of atonality dissonant sounds where experienced as a physical pain.The physiology of deep brain structures (like thalamus, hypothalamus or limbic system) and the physiology of the acoustic pathway process consonant and dissonant sound and musical perceptions in ways, that are similar to the perception of pain. In the thalamus and in the limbic system music and pain meet.The relationships of music and pain is a wide open research field with such interesting questions as the role of dopamine in the perception of consonant or dissonant music, or the processing of pain during music listening. Musicology has not yet embarked on a general investigation of how musical compositions express pain and how that has developed or changed over the centuries. Music therapy, neuro-musicology and the performing arts medicine are scientific fields that offer a lot of ideas for medical and musical research projects. © Georg Thieme Verlag KG Stuttgart · New York.

The relationship between different facets of empathy, pain perception and compassion fatigue among physicians

PubMed Central

Gleichgerrcht, Ezequiel; Decety, Jean

2014-01-01

Background: Medical practitioners such as physicians are continuously exposed to the suffering and the distress of patients. Understanding the way pain perception relates to empathetic dispositions and professional quality of life can contribute to the development of strategies aimed at protecting health professionals from burnout and compassion fatigue. In the present study we investigate the way individual dispositions relate to behavioral measures of pain sensitivity, empathy, and professional quality of life. Methods: A secure Web-based series of self-report measures and a behavioral task were administered to 1,199 board-certified physicians. Additionally, surveys were used to obtain measures of demographic and professional background; dispositional empathy (empathic concern, personal distress, and perspective taking); positive (compassion satisfaction) and negative (burnout and secondary traumatic stress) aspects of their professional life. In the behavioral task, participants were asked to watch a series of video clips of patients experiencing different levels of pain and provide ratings of pain intensity and induced personal distress. Results: Perceived pain intensity was significantly lower among more experienced physicians but similar across specialty fields with varying demands of emotional stress. Watching videos of patients in pain, however, elicited more personal distress among physicians in highly demanding medical fields, despite comparable empathy dispositions with other fields. The pain of male patients was perceived as less intense than the pain of female patients, and this effect was more marked for female physicians. The effect of dispositional empathy on pain perception and induced personal distress was different for each sub-component, with perspective taking and empathic concern (EC) being predictive of the behavioral outcomes. Physicians who experience both compassion satisfaction and fatigue perceive more pain and suffer more personal distress from it than those who only suffer the negative aspects of professional quality of life. Conclusions: Professional experience seems to desensitize physicians to the pain of others without necessarily helping them down-regulate their own personal distress. Pain perception is also related with specific aspects of empathy and varies depending on context, as is the case with the gender of their patients. Minimum levels of empathy appear necessary to benefit from the positive aspects of professional quality of life in medicine. PMID:25071495

Salivary Alpha-Amylase Correlates with Subjective Heat Pain Perception.

PubMed

Wittwer, Amrei; Krummenacher, Peter; La Marca, Roberto; Ehlert, Ulrike; Folkers, Gerd

2016-06-01

Self-reports of pain are important for an adequate therapy. This is a problem with patients and infants who are restricted in providing an accurate verbal estimation of their pain. Reliable, real-time, economical, and non-invasive physiological correlates might contribute to a more comprehensive description of pain. Salivary alpha-amylase constitutes one candidate biomarker, which reflects predominantly sympathetic nervous system alterations under stressful conditions and can be measured non-invasively. The current study investigated the effects of acute heat pain on salivary alpha-amylase activity. Heat pain tolerance was measured on the non-dominant forearm. Participants completed visual analog scales on pain intensity and unpleasantness. Saliva samples were collected directly after pain induction. Twenty-seven healthy volunteers were recruited for this study. While salivary alpha-amylase levels correlated positively with intensity and unpleasantness ratings in response to acute heat pain stimuli, there was no corresponding association with pain tolerance. Salivary alpha-amylase is suggested to be an indirect physiologic correlate of subjective heat pain perception. Future studies should address the role of salivary alpha-amylase depending on the origin of pain, the concerned tissue, and other pain assessment methods. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Cerebral responses and role of the prefrontal cortex in conditioned pain modulation: an fMRI study in healthy subjects

PubMed Central

Bogdanov, Volodymyr B.; Viganò, Alessandro; Noirhomme, Quentin; Bogdanova, Olena V.; Guy, Nathalie; Laureys, Steven; Renshaw, Perry F.; Dallel, Radhouane; Phillips, Christophe; Schoenen, Jean

2017-01-01

The mechanisms underlying conditioned pain modulation (CPM) are multifaceted. We searched for a link between individual differences in prefrontal cortex activity during multi-trial heterotopic noxious cold conditioning and modulation of the cerebral response to phasic heat pain. In 24 healthy female subjects, we conditioned laser heat stimuli to the left hand by applying alternatively ice-cold or lukewarm compresses to the right foot. We compared pain ratings with cerebral fMRI BOLD responses. We also analyzed the relation between CPM and BOLD changes produced by the heterotopic cold conditioning itself, as well as the impact of anxiety and habituation of cold-pain ratings. Specific cerebral activation was identified in precuneus and left posterior insula/SII, respectively, during early and sustained phases of cold application. During cold conditioning, laser pain decreased (n = 7), increased (n = 10) or stayed unchanged (n = 7). At the individual level, the psychophysical effect was directly proportional to the cold-induced modulation of the laser-induced BOLD response in left posterior insula/SII. The latter correlated with the BOLD response recorded 80 s earlier during the initial 10-s phase of cold application in anterior cingulate, orbitofrontal and lateral prefrontal cortices. High anxiety and habituation of cold pain were associated with greater laser heat-induced pain during heterotopic cold stimulation. The habituation was also linked to the early cold-induced orbitofrontal responses. We conclude that individual differences in conditioned pain modulation are related to different levels of prefrontal cortical activation by the early part of the conditioning stimulus, possibly due to different levels in trait anxiety. PMID:25461267

Nipple pain associated with breastfeeding: incorporating current neurophysiology into clinical reasoning.

PubMed

Amir, Lisa H; Jones, Lester E; Buck, Miranda L

2015-03-01

New mothers frequently experience breastfeeding problems, in particular nipple pain. This is often attributed to compression, skin damage, infection or dermatitis. To outline an integrated approach to breastfeeding pain assessment that seeks to enhance current practice. Our clinical reasoning model resolves the complexity of pain into three categories: local stimulation, external influences and central modulation. Tissue pathology, damage or inflammation leads to local stimulation of nociceptors. External influences such as creams and breast pumps, as well as factors related to the mother, the infant and the maternal-infant interaction, may exacerbate the pain. Central nervous system modulation includes the enhancement of nociceptive transmission at the spinal cord and modification of the descending inhibitory influences. A broad range of factors can modulate pain through central mechanisms including maternal illness, exhaustion, lack of support, anxiety, depression or history of abuse. General practitioners (GPs) can use this model to explain nipple pain in complex settings, thus increasing management options for women.

Rab7-a novel redox target that modulates inflammatory pain processing.

PubMed

Kallenborn-Gerhardt, Wiebke; Möser, Christine V; Lorenz, Jana E; Steger, Mirco; Heidler, Juliana; Scheving, Reynir; Petersen, Jonas; Kennel, Lea; Flauaus, Cathrin; Lu, Ruirui; Edinger, Aimee L; Tegeder, Irmgard; Geisslinger, Gerd; Heide, Heinrich; Wittig, Ilka; Schmidtko, Achim

2017-07-01

Chronic pain is accompanied by production of reactive oxygen species (ROS) in various cells that are important for nociceptive processing. Recent data indicate that ROS can trigger specific redox-dependent signaling processes, but the molecular targets of ROS signaling in the nociceptive system remain largely elusive. Here, we performed a proteome screen for pain-dependent redox regulation using an OxICAT approach, thereby identifying the small GTPase Rab7 as a redox-modified target during inflammatory pain in mice. Prevention of Rab7 oxidation by replacement of the redox-sensing thiols modulates its GTPase activity. Immunofluorescence studies revealed Rab7 expression to be enriched in central terminals of sensory neurons. Knockout mice lacking Rab7 in sensory neurons showed normal responses to noxious thermal and mechanical stimuli; however, their pain behavior during inflammatory pain and in response to ROS donors was reduced. The data suggest that redox-dependent changes in Rab7 activity modulate inflammatory pain sensitivity.

Eina! Ouch! Eish! Professionals’ Perceptions of How Children with Cerebral Palsy Communicate About Pain in South African School Settings: Implications for the use of AAC

PubMed Central

Johnson, Ensa; Nilsson, Stefan; Adolfsson, Margareta

2015-01-01

Abstract Most children with severe cerebral palsy experience daily pain that affects their school performance. School professionals need to assess pain in these children, who may also have communication difficulties, in order to pay attention to the pain and support the children’s continued participation in school. In this study, South African school professionals’ perceptions of how they observed pain in children with cerebral palsy, how they questioned them about it and how the children communicated their pain back to them were investigated. Thirty-eight school professionals participated in five focus groups. Their statements were categorized using qualitative content analysis. From the results it became clear that professionals observed children’s pain communication through their bodily expressions, behavioral changes, and verbal and non-verbal messages. Augmentative and alternative communication (AAC) methods were rarely used. The necessity of considering pain-related vocabulary in a multilingual South African context, and of advocating for the use of AAC strategies to enable children with cerebral palsy to communicate their pain was highlighted in this study. PMID:26372118

Pain perception and cardiovascular system response among athletes playing contact sports.

PubMed

Leźnicka, Katarzyna; Pawlak, Matthias; Białecka, Monika; Safranow, Krzysztof; Cięszczyk, Paweł

2017-01-01

The aim of this study was to determine whether the contact sports change the perception of pain as assessed by the cold pressor test (CPT), and if the test induces the same reaction of the cardiovascular system in contact athletes and non-athletes. The study involved 321 healthy men; 140 contact athletes and 181 students of the University of Szczecin (control). Pain threshold and pain tolerance were evaluated using CPT. Cardiovascular measurements were made during CPT. The contact athletes showed a much higher tolerance to pain than the control group (median time 120 vs. 94 s, respectively, p = 0.0002). The thresholds of pain in both groups did not differ significantly between the groups. Systolic blood pressure measured before and during the test in all three measurements was statistically significantly higher in athletes compared with the control group. Heart rate and diastolic blood pressure did not differ significantly between the studied groups.

Being bullied in childhood, and pain and pain perception in adulthood.

PubMed

Sansone, Randy A; Watts, Daron A; Wiederman, Michael W

2014-08-01

While a number of negative health outcomes have been associated with bullying in childhood, we are not aware of any studies examining relationships between bullying in childhood, and pain symptoms and pain perception in adulthood - the focus of the present study. Using a cross-sectional consecutive sample and a self-report survey methodology, we examined among 243 primary-care outpatients a history of being bullied in childhood (yes/no) in relationship to three pain ratings (now, past month, past year) and catastrophic thoughts and feelings about pain as assessed by the Pain Catastrophizing Scale (PCS). Being bullied in childhood was statistically significantly associated with present pain ratings (p < .001) as well as pain ratings over the past month and the past year (p < .01), and with the total score on the PCS as well as each of its sub-scales (i.e. rumination, magnification, helplessness) (p < .001). Being bullied in childhood is associated with higher reported levels of pain at various time points as well as greater levels of self-reported catastrophic thoughts and feelings about pain. Importantly, the methodology of this study does not allow for the examination of a causal relationship. © The Author(s) 2013.

[Analgesia in intensive care medicine].

PubMed

Ortlepp, J R; Luethje, F; Walz, R

2016-02-01

The administration of sedatives and analgesics on the intensive care unit (ICU) is routine daily practice. The correct discrimination between delirium, pain and anxiety or confusion is essential for the strategy and selection of medication. The correct pain therapy and sedation are essential for patient quality of life on the ICU and for the prognosis. The aim of this article is to present state of the art recommendations on the classification of pain and pain therapy on the ICU. An online search was carried out in PubMed for publications on the topics of "pain" and "ICU". Critical care patients are frequently subjected to many procedures and situations which can cause pain. The perception of pain is, among other things, influenced by the degree of orientation, anxiety and the degree of sedation. The administration of analgesics and non-pharmacological approaches are effective in reducing the stress perceived by patients. The main aim is improvement in the awareness of nursing and medical personnel for pain inducers and pain perception in ICU patients. The classification of pain must be made objectively. Therapeutic targets must be defined and in addition to the correct selection of pain medication, non-pharmacological approaches must also be consistently implemented.

Temperament as a modulating factor of pain sensitivity in combat sport athletes.

PubMed

Leźnicka, Katarzyna; Starkowska, Anna; Tomczak, Maciej; Cięszczyk, Paweł; Białecka, Monika; Ligocka, Maria; Żmijewski, Piotr; Pawlak, Maciej

2017-10-15

The aim of this study was to characterise the temperament of combat athletes in comparison to that of individuals who do not practise any sports with regard to pain sensitivity measured with the cold pressor test (CPT) and pressure pain threshold (PPT). The study involved 284 healthy men, aged 18 to 43years. The first group consisted of 198 combat athletes, including boxing (n=19), mixed martial arts (MMA) (n=97) and karate (n=82), aged from 18 to 43years. The control group consisted of 86 subjects between the ages of 18 and 26years, academic students not practising any sport professionally. Pain threshold and pain tolerance were evaluated using the CPT and a pressure algometer. Temperament was measured with the Formal Characteristics of Behaviour - Temperament Inventory (FCB-TI). The contact athletes showed much higher tolerance to pain than the control group using both tools: CPT (p=0.007) and PPT (p<0.001). In athletes, but not in controls, relationships were noted between BMI and endurance (r=0.20; p=0.004), BMI and activity (r=-0.283; p<0.001), BMI and pain threshold (r=0.15; p<0.05), and BMI and pain tolerance (r=0.30; p<0.001), when measured by the algometer - this necessitating adjustment for further analysis. The athletes and students in the study groups differed significantly with regard to intensity of four temperamental traits, but after BMI adjustments only group differences in Preservation, Sensory sensitivity and Emotional reactivity remained significant'. These differences indicate individual differences in perception and reaction to external stimuli. Significantly higher pain tolerance (CPT and PPT) in the athletes studied was related to specific psychological features. The obtained results of temperamental characteristics may indicate higher resilience of the nervous system in combat athletes in comparison to non-athletes. Copyright © 2017 Elsevier Inc. All rights reserved.

Lumbopelvic Core Stabilization Exercise and Pain Modulation Among Individuals with Chronic Nonspecific Low Back Pain.

PubMed

Paungmali, Aatit; Joseph, Leonard H; Sitilertpisan, Patraporn; Pirunsan, Ubon; Uthaikhup, Sureeporn

2017-11-01

Lumbopelvic stabilization training (LPST) may provide therapeutic benefits on pain modulation in chronic nonspecific low back pain conditions. This study aimed to examine the effects of LPST on pain threshold and pain intensity in comparison with the passive automated cycling intervention and control intervention among patients with chronic nonspecific low back pain. A within-subject, repeated-measures, crossover randomized controlled design was conducted among 25 participants (7 males and 18 females) with chronic nonspecific low back pain. All the participants received 3 different types of experimental interventions, which included LPST, the passive automated cycling intervention, and the control intervention randomly, with 48 hours between the sessions. The pressure pain threshold (PPT), hot-cold pain threshold, and pain intensity were estimated before and after the interventions. Repeated-measures analysis of variance showed that LPST provided therapeutic effects as it improved the PPT beyond the placebo and control interventions (P < 0.01). The pain intensity under the LPST condition was significantly better than that under the passive automated cycling intervention and controlled intervention (P < 0.001). Heat pain threshold under the LPST condition also showed a significant trend of improvement beyond the control (P < 0.05), but no significant effects on cold pain threshold were evident. Lumbopelvic stabilization training may provide therapeutic effects by inducing pain modulation through an improvement in the pain threshold and reduction in pain intensity. LPST may be considered as part of the management programs for treatment of chronic low back pain. © 2017 World Institute of Pain.

Effectiveness of an Educational Physiotherapy and Therapeutic Exercise Program in Adult Patients With Hemophilia: A Randomized Controlled Trial.

PubMed

Cuesta-Barriuso, Rubén; Torres-Ortuño, Ana; Nieto-Munuera, Joaquín; López-Pina, José Antonio

2017-05-01

To assess the efficacy of an educational physiotherapy home exercise intervention for physical improvement, pain perception, quality of life, and illness behavior in patients with hemophilic arthropathy. Single-blind randomized controlled trial. Home. Patients with hemophilia (N=20) were randomly allocated to an educational intervention group or to a control group. The educational intervention was performed every 2 weeks over a 15-week period, and home exercises were carried out once a day, 6 days a week, over the same period. Joint status was evaluated using the Gilbert scale; pain was assessed using the visual analog scale; illness behavior was evaluated using the Illness Behavior Questionnaire; and the perception of the quality of life was evaluated using the A36 Hemophilia-QoL questionnaire. We observed significant differences in the intervention group and the control group for both quality of life and illness behavior. There was no significant improvement in joint status; however, an improvement was noted in terms of perception of pain in the ankle. A physiotherapy program based on educational sessions and home exercises can improve the perception of pain in patients with hemophilic arthropathy of the ankle. It improves some variables in the perception of the quality of life and illness behavior. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Pain Management and Use of Opioids in Pediatric Oncology in India: A Qualitative Approach.

PubMed

Angelini, Paola; Boydell, Katherine M; Breakey, Vicky; Kurkure, Purna A; Muckaden, Marian A; Bouffet, Eric; Arora, Brijesh

2017-08-01

Consumption of medical opium for pain relief in India is low, despite the country being one of the main world producers of the substance. We investigated obstacles to opioid use and physician perceptions about optimal pain management in pediatric oncology patients in India. Semistructured interviews were conducted with oncologists who work in pediatric oncology settings. A mixed sampling strategy was used, including maximum variation and confirmation and disconfirmation of cases, as well as snowball sampling. Key informants were identified. Interviews were audio recorded, transcribed verbatim, and analyzed by thematic analysis methodology. Twenty-three interviews were performed across 20 Indian institutions. The main obstacles identified were lack of financial resources, inadequate education of health care providers on pain management, insufficient human resources (particularly lack of dedicated trained oncology nurses), poor access to opioids, and cultural perceptions about pain. Children from rural areas, treated in public hospitals, and from lower socioeconomic classes appear disadvantaged. A significant equality gap exists between public institutions and private institutions, which provide state-of-the-art treatment. The study illuminates the complexity of pain management in pediatric oncology in India, where financial constraints, lack of education, and poor access to opioids play a dominant role, but lack of awareness and cultural perceptions about pain management among health care providers and parents emerged as important contributing factors. Urgent interventions are needed to optimize care in this vulnerable population.

Disrupted functional connectivity of the periaqueductal gray in chronic low back pain

PubMed Central

Yu, Rongjun; Gollub, Randy L.; Spaeth, Rosa; Napadow, Vitaly; Wasan, Ajay; Kong, Jian

2014-01-01

Chronic low back pain is a common neurological disorder. The periaqueductal gray (PAG) plays a key role in the descending modulation of pain. In this study, we investigated brain resting state PAG functional connectivity (FC) differences between patients with chronic low back pain (cLBP) in low pain or high pain condition and matched healthy controls (HCs). PAG seed based functional connectivity (FC) analysis of the functional MR imaging data was performed to investigate the difference among the connectivity maps in the cLBP in the low or high pain condition and HC groups as well as within the cLBP at differing endogenous back pain intensities. Results showed that FC between the PAG and the ventral medial prefrontal cortex (vmPFC)/rostral anterior cingulate cortex (rACC) increased in cLBP patients compared to matched controls. In addition, we also found significant negative correlations between pain ratings and PAG–vmPFC/rACC FC in cLBP patients after pain-inducing maneuver. The duration of cLBP was negatively correlated with PAG–insula and PAG–amygdala FC before pain-inducing maneuver in the patient group. These findings are in line with the impairments of the descending pain modulation reported in patients with cLBP. Our results provide evidence showing that cLBP patients have abnormal FC in PAG centered pain modulation network during rest. PMID:25379421

Evoked potentials after painful cutaneous electrical stimulation depict pain relief during a conditioned pain modulation.

PubMed

Höffken, Oliver; Özgül, Özüm S; Enax-Krumova, Elena K; Tegenthoff, Martin; Maier, Christoph

2017-08-29

Conditioned pain modulation (CPM) evaluates the pain modulating effect of a noxious conditioning stimulus (CS) on another noxious test stimulus (TS), mostly based solely on subjective pain ratings. We used painful cutaneous electrical stimulation (PCES) to induce TS in a novel CPM-model. Additionally, to evaluate a more objective parameter, we recorded the corresponding changes of cortical evoked potentials (PCES-EP). We examined the CPM-effect in 17 healthy subjects in a randomized controlled cross-over design during immersion of the non-dominant hand into 10 °C or 24 °C cold water (CS). Using three custom-built concentric surface electrodes, electrical stimuli were applied on the dominant hand, inducing pain of 40-60 on NRS 0-100 (TS). At baseline, during and after CS we assessed the electrically induced pain intensity and electrically evoked potentials recorded over the central electrode (Cz). Only in the 10 °C-condition, both pain (52.6 ± 4.4 (baseline) vs. 30.3 ± 12.5 (during CS)) and amplitudes of PCES-EP (42.1 ± 13.4 μV (baseline) vs. 28.7 ± 10.5 μV (during CS)) attenuated during CS and recovered there after (all p < 0.001). In the 10 °C-condition changes of subjective pain ratings during electrical stimulation and amplitudes of PCES-EP correlated significantly with each other (r = 0.5) and with CS pain intensity (r = 0.5). PCES-EPs are a quantitative measure of pain relief, as changes in the electrophysiological response are paralleled by a consistent decrease in subjective pain ratings. This novel CPM paradigm is a feasible method, which could help to evaluate the function of the endogenous pain modulation processes. German Clinical Trials Register DRKS-ID: DRKS00012779 , retrospectively registered on 24 July 2017.

Postoperative pain management techniques in hip and knee arthroplasty.

PubMed

Parvizi, Javad; Porat, Manny; Gandhi, Kishor; Viscusi, Eugene R; Rothman, Richard H

2009-01-01

Adequate control of postoperative pain following hip and knee arthroplasty can be a challenging task fraught with potential complications. Postoperative pain is perceived by the patient via a complex network and a multitude of molecular messengers in both the peripheral and central nervous systems. This allows the physician to modulate pain via an array of medications that act on different sites within the body. Using both contemporary and traditional pain modulators, the delivery and timing of these medications can affect postoperative pain and, ultimately, rehabilitation of the arthroplasty patient. Current techniques for controlling pain use both multimodal and preemptive analgesia to improve the outcome of the surgery while minimizing the potential adverse effects of the medications given.

Prevalence of Chronic Pain, Treatments, Perception, and Interference on Life Activities: Brazilian Population-Based Survey

PubMed Central

Perissinotti, Dirce Maria Navas; de Oliveira Junior, Jose Oswaldo; da Fonseca, Paulo Renato Barreiros; Posso, Irimar de Paula

2017-01-01

Background and Objectives Chronic pain affects between 30% and 50% of the world population. Our objective was to estimate the prevalence of chronic pain in Brazil, describe and compare differences between pain types and characteristics, and identify the types of therapies adopted and the impact of pain on daily life. Methods Cross-sectional study of a population-based survey with randomized sample from a private database. The interviews were conducted by phone. 78% of the respondents aged 18 years or more agreed to be interviewed, for a total of 723 respondents distributed throughout the country. Independent variables were demographic data, pain and treatment characteristics, and impact of pain on daily life. Comparative and associative statistical analyses were conducted to select variables for nonhierarchical logistic regression. Results Chronic pain prevalence was 39% and mean age was 41 years with predominance of females (56%). We found higher prevalence of chronic pain in the Southern and Southeastern regions. Pain treatment was not specific to gender. Dissatisfaction with chronic pain management was reported by 49% of participants. Conclusion 39% of interviewed participants reported chronic pain, with prevalence of females. Gender-associated differences were found in intensity perception and interference of pain on daily life activities. PMID:29081680

Parenting in the context of chronic pain: A controlled study of parents with chronic pain

PubMed Central

Wilson, Anna C.; Fales, Jessica L.

2014-01-01

Objectives This study aims to describe what adults with chronic pain experience in their role as parents, utilizing quantitative and qualitative methods. The first aim is to compare parents with chronic pain to parents without chronic pain on perceptions of their adolescent’s pain, parental response to pain, and catastrophizing beliefs about pain. The study also examined predictors of parental protective behaviors, and examined whether these associations differed by study group. Methods Parents with chronic pain (n=58) and parents without chronic pain (n=72) participated, and completed questionnaire measures of pain characteristics and pain interference, as well as measures of parental catastrophizing and protective pain responses. Parents with chronic pain also completed a structured interview about their experience of being a parent. Interview responses were videotaped and subsequently coded for content. Results Compared to controls, parents with chronic pain endorsed more pain in their adolescents, and were more likely to catastrophize about their adolescent’s pain and respond with protective behaviors. Parent’s own pain interference and the perception of higher pain in their adolescent was associated with increased protective parenting in the chronic pain group. Qualitative coding revealed a number of areas of common impact of chronic pain on parenting. Discussion Chronic pain impacts everyday parenting activities and emotions, and impacts pain-specific parent responses that are known to be related to increased pain and pain catastrophizing in children and adolescents. Parents with chronic pain might benefit from interventions that address potential parenting difficulties, and might improve outcomes for their children. PMID:25232862

Expectancy Effects on Conditioned Pain Modulation Are Not Influenced by Naloxone or Morphine.

PubMed

France, Christopher R; Burns, John W; Gupta, Rajnish K; Buvanendran, Asokumar; Chont, Melissa; Schuster, Erik; Orlowska, Daria; Bruehl, Stephen

2016-08-01

Recent studies suggest that participant expectations influence pain ratings during conditioned pain modulation testing. The present study extends this work by examining expectancy effects among individuals with and without chronic back pain after administration of placebo, naloxone, or morphine. This study aims to identify the influence of individual differences in expectancy on changes in heat pain ratings obtained before, during, and after a forearm ischemic pain stimulus. Participants with chronic low back pain (n = 88) and healthy controls (n = 100) rated heat pain experience (i.e., "test stimulus") before, during, and after exposure to ischemic pain (i.e., "conditioning stimulus"). Prior to testing, participants indicated whether they anticipated that their heat pain would increase, decrease, or remain unchanged during ischemic pain. Analysis of the effects of expectancy (pain increase, decrease, or no change), drug (placebo, naloxone, or morphine), and group (back pain, healthy) on changes in heat pain revealed a significant main effect of expectancy (p = 0.001), but no other significant main effects or interactions. Follow-up analyses revealed that individuals who expected lower pain during ischemia reported significantly larger decreases in heat pain as compared with those who expected either no change (p = 0.004) or increased pain (p = 0.001). The present findings confirm that expectancy is an important contributor to conditioned pain modulation effects, and therefore significant caution is needed when interpreting findings that do not account for this individual difference. Opioid mechanisms do not appear to be involved in these expectancy effects.

Decreased sensitivity to thermal pain in rats bred for high anxiety-related behaviour is attenuated by citalopram or diazepam treatment.

PubMed

Jochum, Thomas; Boettger, Michael Karl; Wigger, Alexandra; Beiderbeck, Daniela; Neumann, Inga D; Landgraf, Rainer; Sauer, Heinrich; Bär, Karl-Jürgen

2007-10-01

Complex interactions between pain perception, anxiety and depressive symptoms have repeatedly been described. However, pathophysiological or biochemical mechanisms underlying the alterations of pain perception in patients suffering from anxiety or depression still remain a matter of debate. Thus, we aimed to perform an investigation on pain perception in an animal model of extremes in anxiety-related behaviour, which might provide a tool for future studies. Here, thermal pain thresholds were obtained from rats with a genetic predisposition to high anxiety-related behaviour (HAB), including signs of comorbid depression-like behaviour and from controls (low-anxiety rats (LAB); cross-bred HAB and LAB rats; Wistar rats). Furthermore, the effect of eight-week antidepressive treatment using citalopram and of short-term anxiolytic treatment with diazepam on pain-related behaviour was assessed. Simultaneously, anxiety-related behaviour was monitored. At baseline, HAB animals showed 35% higher thresholds for thermal pain than controls. These were normalized to control levels after eight weeks of continuous citalopram treatment paralleled by a reduction of anxiety-related behaviour, but also acutely after diazepam administration. Overall, thermal pain thresholds in HAB animals are shifted in a similar fashion as seen in patients suffering from major depressive disorder. Antidepressive, as well as anxiolytic treatments, attenuated these differences. As the relative importance of the factors anxiety and depression cannot be derived from this study with certainty, extending these investigations to additional animal models might represent a valuable tool for future investigations concerning the interrelations between anxiety, depression, and pain at a molecular level.

Pain-processing abnormalities in bipolar I disorder, bipolar II disorder, and schizophrenia: A novel trait marker for psychosis proneness and functional outcome?

PubMed

Minichino, Amedeo; Delle Chiaie, Roberto; Cruccu, Giorgio; Piroso, Serena; Di Stefano, Giulia; Francesconi, Marta; Bersani, Francesco Saverio; Biondi, Massimo; Truini, Andrea

2016-11-01

Overlapping neural system dysfunctions, mainly involving the secondary somatosensory cortex (S2), the anterior cingulate cortex (ACC) and the anterior insular cortex (AIC), seem to be related to both pain-perception abnormalities and psychotic symptoms in schizophrenia (SCZ) and bipolar disorder (BD). Laser-evoked potentials (LEPs) were used to investigate pain-perception and central pain-processing abnormalities in SCZ, bipolar I disorder (BD-I), and bipolar II disorder (BD-II), and to evaluate their relationship with history of psychosis, and social-cognitive and functional impairments. Twenty patients with SCZ, 17 patients with BD-I, and 21 patients with BD-II who were all under similar pharmacological treatment underwent clinical, functional, and neuro-psychological assessment. LEPs were analyzed in patients and 19 healthy subjects (HS). LEPs elicit responses reflecting the activity of the S2 (N1 wave) and the ACC/AIC cortices (N2/P2 complex). A four-group ANOVA was conducted between patients and HS to compare pain-perceptive thresholds (PThs), N1, and N2/P2-LEP components. Compared to HS: (i) patients with SCZ showed pain-processing and pain-perception abnormalities, as revealed by significantly higher PTh (P<.01), and lower N1 (P<.01) and N2/P2 (P<.01) amplitudes, (ii) patients with BD-I showed only pain-processing abnormalities, as revealed by significantly lower N1 (P<.05) and N2 (P<.01) amplitudes; and patients with BD-II did not differ for any of the LEP variables investigated. N1 and N2 amplitudes negatively correlated to history of psychosis (P<.01), social-cognition (P<.05), and real-world functioning (P<.01) measures in the whole group of patients. To the best of our knowledge, this is the first study comparing central pain processing in patients with SCZ, BD-I, and BD-II. Our results suggest that pain-processing abnormalities may represent a novel locus of interest for research investigating trait markers of the psychosis spectrum. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Fear of pain, pain catastrophizing, and acute pain perception: relative prediction and timing of assessment.

PubMed

Hirsh, Adam T; George, Steven Z; Bialosky, Joel E; Robinson, Michael E

2008-09-01

Pain-related fear and catastrophizing are important variables of consideration in an individual's pain experience. Methodological limitations of previous studies limit strong conclusions regarding these relationships. In this follow-up study, we examined the relationships between fear of pain, pain catastrophizing, and experimental pain perception. One hundred healthy volunteers completed the Fear of Pain Questionnaire (FPQ-III), Pain Catastrophizing Scale (PCS), and Coping Strategies Questionnaire-Catastrophizing scale (CSQ-CAT) before undergoing the cold pressor test (CPT). The CSQ-CAT and PCS were completed again after the CPT, with participants instructed to complete these measures based on their experience during the procedure. Measures of pain threshold, tolerance, and intensity were collected and served as dependent variables in separate regression models. Sex, pain catastrophizing, and pain-related fear were included as predictor variables. Results of regression analyses indicated that after controlling for sex, pain-related fear was a consistently stronger predictor of pain in comparison to catastrophizing. These results were consistent when separate measures (CSQ-CAT vs PCS) and time points (pretask vs "in vivo") of catastrophizing were used. These findings largely corroborate those from our previous study and are suggestive of the absolute and relative importance of pain-related fear in the experimental pain experience. Although pain-related fear has received less attention in the experimental literature than pain catastrophizing, results of the current study are consistent with clinical reports highlighting this variable as an important aspect of the experience of pain.

The causal role of the somatosensory cortex in prosocial behaviour

PubMed Central

Gallo, Selene; Paracampo, Riccardo; Müller-Pinzler, Laura; Severo, Mario Carlo; Suttrup, Judith; Avenanti, Alessio; Keysers, Christian

2018-01-01

Witnessing another person’s suffering elicits vicarious brain activity in areas that are active when we ourselves are in pain. Whether this activity influences prosocial behavior remains the subject of debate. Here participants witnessed a confederate express pain through a reaction of the swatted hand or through a facial expression, and could decide to reduce that pain by donating money. Participants donate more money on trials in which the confederate expressed more pain. Electroencephalography shows that activity of the somatosensory cortex I (SI) hand region explains variance in donation. Transcranial magnetic stimulation (TMS) shows that altering this activity interferes with the pain–donation coupling only when pain is expressed by the hand. High-definition transcranial direct current stimulation (HD-tDCS) shows that altering SI activity also interferes with pain perception. These experiments show that vicarious somatosensory activations contribute to prosocial decision-making and suggest that they do so by helping to transform observed reactions of affected body-parts into accurate perceptions of pain that are necessary for decision-making. PMID:29735015

Discovery of unexpected pain in intubated and sedated patients.

PubMed

Clukey, Lory; Weyant, Ruth A; Roberts, Melanie; Henderson, Ann

2014-05-01

The perceptions of patients who are restrained and sedated while being treated with mechanical ventilation in the intensive care unit are not well understood. The effectiveness of sedation used to aid in recovery and enhance comfort during intubation is unknown. To explore the perceptions of patients who were intubated and receiving pain medication while sedated and restrained in the intensive care unit, in particular, their experience and their memories of the experience. In a phenomenological study, 14 patients who were intubated and receiving pain medication while sedated and restrained were interviewed at the bedside. A semistructured interview guide was used. Data were analyzed by using an inductive method consistent with qualitative research. Three major themes were identified from the data: lack of memory of being restrained; a perception of being intubated as horrific; nursing behaviors that were helpful and comforting. An unexpected discovery was that sedation may be interfering with pain assessment and management. Being intubated can be painful and traumatic despite administration of sedatives and analgesics. Sedation may mask uncontrolled pain for intubated patients and prevent them from communicating this condition to a nurse. Nurses may need to evaluate current interventions in order to provide maximum comfort and promote optimal positive outcomes for intensive care patients who are intubated.

Impact of reassurance on pain perception in patients with primary burning mouth syndrome.

PubMed

Brailo, V; Firić, M; Vučićević Boras, V; Andabak Rogulj, A; Krstevski, I; Alajbeg, I

2016-09-01

In spite of extensive research, no effective treatment of primary burning mouth syndrome (BMS) still exists. The aim of this study was to determine the impact of informative intervention/reassurance on pain perception and quality of life in patients with primary BMS. Informative intervention/reassurance was undertaken in 28 patients diagnosed with primary BMS. Patients received information about all aspects of BMS verbally and in an informative leaflet. Numerical scale (0-10), Pain Catastrophizing Scale and Oral Health Impact Profile-14 (OHIP-14) were used to assess pain intensity, pain perception, and quality of life before the intervention and 6 months after. No other treatment was given to the patients. Significant reduction in symptom intensity, pain catastrophizing along with positive increase in the quality of life compared with baseline, was observed on a follow-up examination 6 months after the informative intervention (P < 0.001). The results of this study confirm that objective informing/reassurance of patients with primary BMS can result in decreased catastrophizing and improvement in the quality of life. By eliminating/changing negative patterns of behavior, a reduction in symptoms comparable with pharmacological treatment can be achieved. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of interferential current therapy on pain perception and disability level in subjects with chronic low back pain: a randomized controlled trial.

PubMed

Albornoz-Cabello, Manuel; Maya-Martín, Julián; Domínguez-Maldonado, Gabriel; Espejo-Antúnez, Luis; Heredia-Rizo, Alberto Marcos

2017-02-01

To assess the short-term efficacy of transregional interferential current therapy on pain perception and disability level in chronic non-specific low back pain. A randomized, single-blinded (the assessor collecting the outcome data was blinded), controlled trial. A private physiotherapy research clinic. A total of 64 individuals, 20 men and 44 women, mean (SD) age was 51 years (11.93), with low back pain of more than three months, with or without pain radiating to the lower extremities above the knee, were distributed into a control ( n = 20) or an experimental group ( n = 44). A 2:1 randomization ratio was used in favour of the latter. A transregional interferential current electrotherapy protocol was performed for participants in the experimental group, while the control group underwent a 'usual care' treatment (massage, mobilization and soft-tissue techniques). All subjects received up to 10 treatment sessions of 25 minutes over a two-week period, and completed the intervention and follow-up evaluations. Self-perceived pain was assessed with a Visual Analogue Scale. Secondary measure included the Oswestry Low Back Disability Index. Evaluations were collected at baseline and after the intervention protocol. Significant between-group differences were found for interferential current therapy on pain perception ( p = 0.032) and disability level ( p = 0.002). The observed differences in the between-group mean changes were of 11.34 mm (1.77/20.91) and 13.38 points (4.97/21.78), respectively. A two-week transregional interferential current treatment has shown significant short-term efficacy, when compared with a 'usual care' protocol, on self-perceived pain and functionality in subjects with chronic low back pain.

Impaired conditioned pain modulation in youth with functional abdominal pain

PubMed Central

Morris, Matthew C.; Walker, Lynn S.; Bruehl, Stephen; Stone, Amanda L.; Mielock, Alyssa S.; Rao, Uma

2016-01-01

Functional abdominal pain (FAP) is associated with enhanced pain responsiveness. Although impaired conditioned pain modulation (CPM) characterizes adults with a variety of chronic pain conditions, relatively little is known about CPM in youth with FAP. The present study assessed CPM to evoked thermal pain in 140 youth (ages 10 to 17), 63 of whom had FAP and 77 of whom were healthy controls. Multilevel models demonstrated weaker CPM effects in FAP than healthy youth, as evident in slower within-person decreases in pain ratings during the conditioning phase. Weaker CPM effects were associated with greater somatic symptom severity and functional disability. Pain responses in FAP youth were heterogeneous, with 43% of youth showing an unexpected increase in pain ratings during the conditioning phase, suggesting sensitization rather than CPM-related pain inhibition. These findings highlight directions for future research on the emergence and maintenance of FAP in youth. PMID:27389918

Impaired conditioned pain modulation in youth with functional abdominal pain.

PubMed

Morris, Matthew C; Walker, Lynn S; Bruehl, Stephen; Stone, Amanda L; Mielock, Alyssa S; Rao, Uma

2016-10-01

Functional abdominal pain (FAP) is associated with enhanced pain responsiveness. Although impaired conditioned pain modulation (CPM) characterizes adults with a variety of chronic pain conditions, relatively little is known about CPM in youth with FAP. This study assessed CPM to evoked thermal pain in 140 youth (ages 10-17), 63 of whom had FAP and 77 of whom were healthy controls. Multilevel models demonstrated weaker CPM effects in youth with FAP than in healthy youth, as evident in slower within-person decreases in pain ratings during the conditioning phase. Weaker CPM effects were associated with greater somatic symptom severity and functional disability. Pain responses in youth with FAP were heterogeneous, with 43% of youth showing an unexpected increase in pain ratings during the conditioning phase, suggesting sensitization rather than CPM-related pain inhibition. These findings highlight directions for future research on the emergence and maintenance of FAP in youth.

Nonpainful wide-area compression inhibits experimental pain

PubMed Central

Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena

2016-01-01

Abstract Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM. PMID:27152691

Performing music can induce greater modulation of emotion-related psychophysiological responses than listening to music.

PubMed

Nakahara, Hidehiro; Furuya, Shinichi; Masuko, Tsutomu; Francis, Peter R; Kinoshita, Hiroshi

2011-09-01

The present study investigated the differential effects of music-induced emotion on heart rate (HR) and its variability (HRV) while playing music on the piano and listening to a recording of the same piece of music. Sixteen pianists were monitored during tasks involving emotional piano performance, non-emotional piano performance, emotional perception, and non-emotional perception. It was found that emotional induction during both perception and performance modulated HR and HRV, and that such modulations were significantly greater during musical performance than during perception. The results confirmed that musical performance was far more effective in modulating emotion-related autonomic nerve activity than musical perception in musicians. The findings suggest the presence of a neural network of reward-emotion-associated autonomic nerve activity for musical performance that is independent of a neural network for musical perception. Copyright © 2011 Elsevier B.V. All rights reserved.

Poor Illness Perceptions Are a Risk Factor for Depressive and Anxious Symptomatology in Fibromyalgia Syndrome: A Longitudinal Cohort Study.

PubMed

de Heer, Eric W; Vriezekolk, Johanna E; van der Feltz-Cornelis, Christina M

2017-01-01

Patients with widespread pain, such as in fibromyalgia, are vulnerable for depression and anxiety, which composes a relevant public health problem. Identifying risk factors for the onset of depression and anxiety is therefore warranted. Objective of this study was to determine whether severe pain, maladaptive coping, and poor illness perceptions are associated with depressive and anxious symptomatology in fibromyalgia. Consecutive patients referred to an outpatient clinic completed sets of physical and psychological questionnaires at baseline and at 18-month follow-up. A total of 452 patients with fibromyalgia syndrome (FMS) were eligible for inclusion, and subsequently, 280 patients returned the baseline questionnaire. Depressive and anxious symptomatology was measured with the Hospital Anxiety and Depression Scale. To measure pain severity, coping style, and illness perceptions, the Fibromyalgia Impact Questionnaire, Pain Coping Inventory, and the Illness Perception Questionnaire-Revised (IPQ-R) were used, respectively. Multivariable logistic regression analyses, bootstrapping and calibration, were performed to examine the association of pain severity, pain coping, and illness perception with depressive and anxiety symptoms at follow-up, adjusted for sociodemographic variables. Initial level of depressive and anxiety symptoms was selected as covariates. Mean age was 42.6 years and 95.4% were female. At 18-month follow-up, 68 (of the 195) patients were depressed and 80 (of the 197) were anxious. Only the IPQ-R subscale "emotional representations" showed a significant positive association with depressive symptoms at follow-up (OR = 1.10), next to the initial level of depressive symptoms (OR = 1.30). In case of anxiety, only the IPQ-R subscale "treatment control" showed a significant negative association with anxiety symptoms at follow-up (OR = 0.87), next to the initial level of anxiety symptoms (OR = 1.45). Our data suggest that not pain severity or maladaptive coping, but poor illness perceptions are important in elevated depressive and anxious symptomatology. Patients with fibromyalgia who think their illness negatively affects their mental well-being are at increased risk for more depressive symptoms, and those who think treatment of their illness will not be effective are at increased risk for more anxiety symptoms. Strengthening illness beliefs and reducing catastrophic thinking, therefore, seem crucial factors in the treatment of patients with FMS.

Subliminal stimuli modulate somatosensory perception rhythmically and provide evidence for discrete perception

PubMed Central

Baumgarten, Thomas J.; Königs, Sara; Schnitzler, Alfons; Lange, Joachim

2017-01-01

Despite being experienced as continuous, there is an ongoing debate if perception is an intrinsically discrete process, with incoming sensory information treated as a succession of single perceptual cycles. Here, we provide causal evidence that somatosensory perception is composed of discrete perceptual cycles. We used in humans an electrotactile temporal discrimination task preceded by a subliminal (i.e., below perceptual threshold) stimulus. Although not consciously perceived, subliminal stimuli are known to elicit neuronal activity in early sensory areas and modulate the phase of ongoing neuronal oscillations. We hypothesized that the subliminal stimulus indirectly, but systematically modulates the ongoing oscillatory phase in S1, thereby rhythmically shaping perception. The present results confirm that, without being consciously perceived, the subliminal stimulus critically influenced perception in the discrimination task. Importantly, perception was modulated rhythmically, in cycles corresponding to the beta-band (13–18 Hz). This can be compellingly explained by a model of discrete perceptual cycles. PMID:28276493

Separating brain processing of pain from that of stimulus intensity.

PubMed

Oertel, Bruno G; Preibisch, Christine; Martin, Till; Walter, Carmen; Gamer, Matthias; Deichmann, Ralf; Lötsch, Jörn

2012-04-01

Regions of the brain network activated by painful stimuli are also activated by nonpainful and even nonsomatosensory stimuli. We therefore analyzed where the qualitative change from nonpainful to painful perception at the pain thresholds is coded. Noxious stimuli of gaseous carbon dioxide (n = 50) were applied to the nasal mucosa of 24 healthy volunteers at various concentrations from 10% below to 10% above the individual pain threshold. Functional magnetic resonance images showed that these trigeminal stimuli activated brain regions regarded as the "pain matrix." However, most of these activations, including the posterior insula, the primary and secondary somatosensory cortex, the amygdala, and the middle cingulate cortex, were associated with quantitative changes in stimulus intensity and did not exclusively reflect the qualitative change from nonpainful to pain. After subtracting brain activations associated with quantitative changes in the stimuli, the qualitative change, reflecting pain-exclusive activations, could be localized mainly in the posterior insular cortex. This shows that cerebral processing of noxious stimuli focuses predominately on the quantitative properties of stimulus intensity in both their sensory and affective dimensions, whereas the integration of this information into the perception of pain is restricted to a small part of the pain matrix. Copyright © 2011 Wiley Periodicals, Inc.

Abnormal Pain Modulation in Patients with Spatially Distributed Chronic Pain: Fibromyalgia

PubMed Central

Staud, Roland

2009-01-01

Many chronic pain syndromes including fibromyalgia, irritable bowel syndrome, chronic fatigue syndrome, migraine headache, chronic back pain, and complex regional pain syndrome are associated with hypersensitivity to painful stimuli and with reduced endogenous pain inhibition. These findings suggest that modulation of pain-related information may be related to the onset and/or maintenance of chronic pain. Although pain sensitivity and pain inhibition are normally distributed in the general population, they are not useful as reliable predictors of future pain. The combination of heightened pain sensitivity and reduced pain-inhibition, however, appears to predispose individuals to greater risk for increased acute clinical pain (e.g., postoperative pain). It is unknown at this time whether such pain processing abnormalities may also place individuals at increased risk for chronic pain. Psychophysical methods, including heat sensory and pressure pain testing have become increasingly available and can be used for the evaluation of pain sensitivity and pain inhibition. However, long-term prospective studies in the general population are lacking which could yield insight into the role of heightened pain sensitivity and pain disinhibition for the development of chronic pain disorders like fibromyalgia. PMID:19647141

Dyadic analysis of child and parent trait and state pain catastrophizing in the process of children's pain communication.

PubMed

Birnie, Kathryn A; Chambers, Christine T; Chorney, Jill; Fernandez, Conrad V; McGrath, Patrick J

2016-04-01

When explored separately, child and parent catastrophic thoughts about child pain show robust negative relations with child pain. The objective of this study was to conduct a dyadic analysis to elucidate intrapersonal and interpersonal influences of child and parent pain catastrophizing on aspects of pain communication, including observed behaviours and perceptions of child pain. A community sample of 171 dyads including children aged 8 to 12 years (89 girls) and parents (135 mothers) rated pain catastrophizing (trait and state versions) and child pain intensity and unpleasantness following a cold pressor task. Child pain tolerance was also assessed. Parent-child interactions during the cold pressor task were coded for parent attending, nonattending, and other talk, and child symptom complaints and other talk. Data were analyzed using the actor-partner interdependence model and hierarchical multiple regressions. Children reporting higher state pain catastrophizing had greater symptom complaints regardless of level of parent state pain catastrophizing. Children reporting low state pain catastrophizing had similar high levels of symptom complaints, but only when parents reported high state pain catastrophizing. Higher child and parent state and/or trait pain catastrophizing predicted their own ratings of higher child pain intensity and unpleasantness, with child state pain catastrophizing additionally predicting parent ratings. Higher pain tolerance was predicted by older child age and lower child state pain catastrophizing. These newly identified interpersonal effects highlight the relevance of the social context to children's pain expressions and parent perceptions of child pain. Both child and parent pain catastrophizing warrant consideration when managing child pain.

Association of serum total antioxidant capacity and total oxidant status with pain perception in patients with myofacial pain dysfunction.

PubMed

Etoz, Osman A; Ataoglu, Hanife; Erel, Ozcan; Celik, Hakim; Herken, Emine Nur; Bayazit, Yildirim Ahmet

2009-01-01

We aimed to find out the association of total antioxidant capacity (TAC) and total oxidant status (TOS) with generalized pressure pain thresholds (PPT) of patients with myofacial pain dysfunction (MPD). PPT scores of patients with MPD (n = 37) and healthy individuals (n = 43) were measured on the hypothenar region of the hand using a mechanical algometer. Serum samples were collected and TAC and TOS were measured by novel methods. The TAC of patients was significantly lower than that of the control subjects. The difference between the TOS measurements of patients and control subjects was not significant. The PPT scores of the patients were significantly lower than that of control subjects. There may be an association between serum antioxidant capacity and MPD. Low serum TAC might also be related with pain perception.

[MODERN VIEWS ON THE PHARMACOGENETICS OF PAIN.

PubMed

Makharin, O A; Zhenilo, V M; Patyuchenko, O Yu

2017-09-01

Quality anesthesia during surgery and in the postoperative period remains a topical problem of modern anesthesiology. The study of genetic characteristics of a patient is a goal that may be allow us to develop a personalized approach to solve this problem. The purpose of the review is a synthesis of literature data about the influence of genetic factors on pain perception and its treatment. The review included information obtained from SCOPUS, MedLine, EMBASE. The search keywords were: pain, pharmacogenetics, polymorphism, analgesics.Describe the effect ofgene polymorphisms of OPRM, 5HTRIA, 5HTR2A, COMT GCHI, SCN9A, KCNSI, CACNA2D3, CACNG2, PTGSI, PTGS2, MDRJ/ABCB] on the perception of pain, and CYP2D6, CYP2C9, CYP3A4 on the pharmacokinetics and pharmacodynamics of medi- cations used in the treatment of pain.

E-learning module on chronic low back pain in older adults: evidence of effect on medical student objective structured clinical examination performance.

PubMed

Weiner, Debra K; Morone, Natalia E; Spallek, Heiko; Karp, Jordan F; Schneider, Michael; Washburn, Carol; Dziabiak, Michael P; Hennon, John G; Elnicki, D Michael

2014-06-01

The Institute of Medicine has highlighted the urgent need to close undergraduate and graduate educational gaps in treating pain. Chronic low back pain (CLBP) is one of the most common pain conditions, and older adults are particularly vulnerable to potential morbidities associated with misinformed treatment. An e-learning case-based interactive module was developed at the University of Pittsburgh Center of Excellence in Pain Education, one of 12 National Institutes of Health-designated centers, to teach students important principles for evaluating and managing CLBP in older adults. A team of six experts in education, information technology, pain management, and geriatrics developed the module. Teaching focused on common errors, interactivity, and expert modeling and feedback. The module mimicked a patient encounter using a standardized patient (the older adult with CLBP) and a pain expert (the patient provider). Twenty-eight medical students were not exposed to the module (Group 1) and 27 were exposed (Group 2). Their clinical skills in evaluating CLBP were assessed using an objective structured clinical examination (OSCE). Mean scores were 62.0 ± 8.6 for Group 1 and 79.5 ± 10.4 for Group 2 (P < .001). Using an OSCE pass-fail cutoff score of 60%, 17 of 28 Group 1 students (60.7%) and 26 of 27 Group 2 students (96.3%) passed. The CLBP OSCE was one of 10 OSCE stations in which students were tested at the end of a Combined Ambulatory Medicine and Pediatrics Clerkship. There were no between-group differences in performance on eight of the other nine OSCE stations. This module significantly improved medical student clinical skills in evaluating CLBP. Additional research is needed to ascertain the effect of e-learning modules on more-advanced learners and on improving the care of older adults with CLBP. © 2014, Copyright the Authors Journal compilation © 2014, The American Geriatrics Society.

E-Learning Module on Chronic Low Back Pain in Older Adults: Evidence of Effect on Medical Student Objective Structured Clinical Examination Performance

PubMed Central

Weiner, Debra K.; Morone, Natalia E.; Spallek, Heiko; Karp, Jordan F.; Schneider, Michael; Washburn, Carol; Dziabiak, Michael P.; Hennon, John G.; Elnicki, D. Michael

2015-01-01

The Institute of Medicine has highlighted the urgent need to close undergraduate and graduate educational gaps in treating pain. Chronic low back pain (CLBP) is one of the most common pain conditions, and older adults are particularly vulnerable to potential morbidities associated with misinformed treatment. An e-learning case-based interactive module was developed at the University of Pittsburgh Center of Excellence in Pain Education, one of 12 National Institutes of Health–designated centers, to teach students important principles for evaluating and managing CLBP in older adults. A team of six experts in education, information technology, pain management, and geriatrics developed the module. Teaching focused on common errors, interactivity, and expert modeling and feedback. The module mimicked a patient encounter using a standardized patient (the older adult with CLBP) and a pain expert (the patient provider). Twenty-eight medical students were not exposed to the module (Group 1) and 27 were exposed (Group 2). Their clinical skills in evaluating CLBP were assessed using an objective structured clinical examination (OSCE). Mean scores were 62.0 ± 8.6 for Group 1 and 79.5 ± 10.4 for Group 2 (P < .001). Using an OSCE pass–fail cutoff score of 60%, 17 of 28 Group 1 students (60.7%) and 26 of 27 Group 2 students (96.3%) passed. The CLBP OSCE was one of 10 OSCE stations in which students were tested at the end of a Combined Ambulatory Medicine and Pediatrics Clerkship. There were no between-group differences in performance on eight of the other nine OSCE stations. This module significantly improved medical student clinical skills in evaluating CLBP. Additional research is needed to ascertain the effect of e-learning modules on more-advanced learners and on improving the care of older adults with CLBP. PMID:24833496

Increased excitability of spinal pain reflexes and altered frequency-dependent modulation in the dopamine D3-receptor knockout mouse.

PubMed

Keeler, Benjamin E; Baran, Christine A; Brewer, Kori L; Clemens, Stefan

2012-12-01

Frequency-dependent modulation and dopamine (DA) receptors strongly modulate neural circuits in the spinal cord. Of the five known DA receptor subtypes, the D3 receptor has the highest affinity to DA, and D3-mediated actions are mainly inhibitory. Using an animal model of spinal sensorimotor dysfunction, the D3 receptor knockout mouse (D3KO), we investigated the physiological consequences of D3 receptor dysfunction on pain-associated signaling pathways in the spinal cord, the initial integration site for the processing of pain signaling. In the D3KO spinal cord, inhibitory actions of DA on the proprioceptive monosynaptic stretch reflex are converted from depression to facilitation, but its effects on longer-latency and pain-associated reflex responses and the effects of FM have not been studied. Using behavioral approaches in vivo, we found that D3KO animals exhibit reduced paw withdrawal latencies to thermal pain stimulation (Hargreaves' test) over wild type (WT) controls. Electrophysiological and pharmacological approaches in the isolated spinal cord in vitro showed that constant current stimulation of dorsal roots at a pain-associated frequency was associated with a significant reduction in the frequency-dependent modulation of longer-latency reflex (LLRs) responses but not monosynaptic stretch reflexes (MSRs) in D3KO. Application of the D1 and D2 receptor agonists and the voltage-gated calcium-channel ligand, pregabalin, but not DA, was able to restore the frequency-dependent modulation of the LLR in D3KO to WT levels. Thus we demonstrate that nociception-associated LLRs and proprioceptive MSRs are differentially modulated by frequency, dopaminergics and the Ca(2+) channel ligand, pregabalin. Our data suggest a role for the DA D3 receptor in pain modulation and identify the D3KO as a possible model for increased nociception. Copyright © 2012 Elsevier Inc. All rights reserved.

TRPV1 Antagonists and Chronic Pain: Beyond Thermal Perception

PubMed Central

Brandt, Michael R.; Beyer, Chad E.; Stahl, Stephen M.

2012-01-01

In the last decade, considerable evidence as accumulated to support the development of Transient Receptor Potential Vanilloid 1 (TRPV1) antagonists for the treatment of various chronic pain conditions. Whereas there is a widely accepted rationale for the development of TRPV1 antagonists for the treatment of various inflammatory pain conditions, their development for indications of chronic pain, where conditions of tactical, mechanical and spontaneous pain predominate, is less clear. Preclinical localization and expression studies provide a firm foundation for the use of molecules targeting TRPV1 for conditions of bone pain, osteoarthritis and neuropathic pain. Selective TRPV1 antagonists weakly attenuate tactile and mechanical hypersensivity and are partially effective for behavioral and electrophysiological endpoints that incorporate aspects of spontaneous pain. While initial studies with TRPV1 antagonist in normal human subjects indicate a loss of warm thermal perception, clinical studies assessing allelic variants suggests that TRPV1 may mediate other sensory modalities under certain conditions. The focus of this review is to summarize the current perspectives of TRPV1 for the treatment of conditions beyond those with a primary thermal sensitivity. PMID:24288084

Comparative Analysis of Registered Nurses' and Nursing Students' Attitudes and Use of Nonpharmacologic Methods of Pain Management.

PubMed

Stewart, Malcolm; Cox-Davenport, Rebecca A

2015-08-01

Despite the benefits that nonpharmacologic methods of pain management have to offer, nurses cite barriers that inhibit their use in practice. The purpose of this research study was to compare the perceptions of prelicensed student nurses (SNs) and registered nurses (RNs) toward nonpharmacologic methods of pain management. A sample size of 64 students and 49 RNs was recruited. Each participant completed a questionnaire about their use and perceptions nonpharmacologic pain control methods. Sixty-nine percent of RNs reported a stronger belief that nonpharmacologic methods gave relief to their patients compared with 59% of SNs (p = .028). Seventy-five percent of student nurses felt they had adequate education about nonpharmacologic pain modalities compared with 51% of RN who felt less than adequately educated (p = .016). These findings highlight the need for education about nonpharmacologic approaches to pain management. Applications of these findings may decrease barriers to the use of nonpharmacologic methods of pain management. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Single-Spot Yellow Laser Versus Conventional Green Laser on Panretinal Photocoagulation: Patient Pain Scores and Preferences.

PubMed

González-Saldivar, Gerardo; Rojas-Juárez, Sergio; Espinosa-Soto, Itzel; Sánchez-Ramos, Jorge; Jaurieta-Hinojosa, Noel; Ramírez-Estudillo, Abel

2017-11-01

Panretinal photocoagulation (PRP) is the mainstay therapy for proliferative diabetic retinopathy. Pain during and after its application is a complication that affects patients' therapeutic adherence. This study aimed to compare pain perception and patient preference for the 577-nm yellow laser (YL-577) (LIGHTL as 577; LIGHTMED, San Clemente, CA) and the conventional 532-nm green laser (GL-532) (Purepoint Laser; Alcon, Fort Worth, TX) with PRP. A total of 92 patient eyes with proliferative diabetic retinopathy treated with PRP were randomly assigned to receive both GL-532 and YL-577 (184 eyes) - one on each eye, with the order of application randomized, as well. Afterward, verbal rapid answer and visual analogue scale (VAS) scores for pain perception and patient preference were evaluated. VAS score was 7 ± 2 for the GL-532 group compared to 5 ± 3 in the YL-577 group (P = .001). Overall, 75% of the patients preferred YL-577 therapy if they were to receive a second PRP session. The use of YL-577 as an alternative approach for PRP reduces pain perception and is preferred by patients. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:902-905.]. Copyright 2017, SLACK Incorporated.

Modulation of thermal pain-related brain activity with virtual reality: evidence from fMRI.

PubMed

Hoffman, Hunter G; Richards, Todd L; Coda, Barbara; Bills, Aric R; Blough, David; Richards, Anne L; Sharar, Sam R

2004-06-07

This study investigated the neural correlates of virtual reality analgesia. Virtual reality significantly reduced subjective pain ratings (i.e. analgesia). Using fMRI, pain-related brain activity was measured for each participant during conditions of no virtual reality and during virtual reality (order randomized). As predicted, virtual reality significantly reduced pain-related brain activity in all five regions of interest; the anterior cingulate cortex, primary and secondary somatosensory cortex, insula, and thalamus (p<0.002, corrected). Results showed direct modulation of human brain pain responses by virtual reality distraction. Copyright 2004 Lippincott Williams and Wilkins

Disparities Between Clinician and Patient Perception of Breakthrough Pain Control.

PubMed

Webber, Katherine; Davies, Andrew N; Cowie, Martin R

2016-05-01

There are disparities in the level of symptom severity as perceived by patients and health professionals. There is limited information about patients' and clinicians' global assessment of breakthrough pain control, the need to change analgesics, and change in breakthrough pain over time. To establish whether patients and clinicians independently agree on adequacy of breakthrough pain control, management strategy, and impression of change over time. One hundred patients with breakthrough cancer pain were assessed and followed up one week later by a palliative medicine specialist. The patient and clinician independently answered the same questions about the adequacy of the patient's breakthrough pain control and breakthrough pain management. The results were compared with items on the Breakthrough Pain Assessment Tool (BAT). At initial consultation, 35% of patients rated their breakthrough cancer pain as inadequately controlled compared with 72% of clinicians. Breakthrough pain analgesics were changed in 68% of cases. At one-week follow-up consultation, 62% of patients considered their breakthrough cancer pain to be better, and in 57% of cases, the clinicians also categorized the pain this way. There are significant differences in global impressions of breakthrough pain between patients and pain clinicians that become less disparate as a therapeutic relationship evolves. Therapeutic decisions were based on clinical rather than patient perceptions. Copyright © 2016 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

Drug Management of Visceral Pain: Concepts from Basic Research

PubMed Central

Davis, Mellar P.

2012-01-01

Visceral pain is experienced by 40% of the population, and 28% of cancer patients suffer from pain arising from intra- abdominal metastasis or from treatment. Neuroanatomy of visceral nociception and neurotransmitters, receptors, and ion channels that modulate visceral pain are qualitatively or quantitatively different from those that modulate somatic and neuropathic pain. Visceral pain should be recognized as distinct pain phenotype. TRPV1, Na 1.8, and ASIC3 ion channels and peripheral kappa opioid receptors are important mediators of visceral pain. Mu agonists, gabapentinoids, and GABAB agonists reduce pain by binding to central receptors and channels. Combinations of analgesics and adjuvants in animal models have supra-additive antinociception and should be considered in clinical trials. This paper will discuss the neuroanatomy, receptors, ion channels, and neurotransmitters important to visceral pain and provide a basic science rationale for analgesic trials and management. PMID:22619712

Altered Pain Perception and Fear-Learning Deficits in Subjects With Posttraumatic Stress Disorder.

PubMed

Jenewein, Josef; Erni, Jeannine; Moergeli, Hanspeter; Grillon, Christian; Schumacher, Sonja; Mueller-Pfeiffer, Christoph; Hassanpour, Katayun; Seiler, Annina; Wittmann, Lutz; Schnyder, Ulrich; Hasler, Gregor

2016-12-01

There is growing evidence that fear-learning abnormalities are involved in the development of posttraumatic stress disorder (PTSD) and chronic pain. More than 50% of PTSD patients suffer from chronic pain. This study aimed to examine the role of fear-learning deficits in the link between pain perception and PTSD. We included 19 subjects with PTSD and 21 age- and sex-matched healthy control subjects in a fear-conditioning experiment. The conditioned stimulus (CS) consisted of visual signs flashed upon a screen in front of each subject. The unconditioned stimulus was either a low or high temperature impulse delivered through a thermal contact thermode on the subjects' hand. A designation of 'CS-' was assigned to CS always followed by nonpainful low-temperature stimuli; a designation of 'CS+' was given to CS that were randomly followed by either a low or a more painful high temperature. Skin conductance was used as a physiological marker of fear. In healthy control subjects, CS+ induced more fear than CS-, and a low-temperature stimulus induced less subjective pain after CS- than after CS+. PTSD subjects failed to demonstrate such adaptive conditioning. Fear ratings after CS presentation were significantly higher in the PTSD group than in the control group. There were significant interaction effects between group and the type of CS on fear and pain ratings. Fear-learning deficits are a potentially promising, specific psychopathological factor in altered pain perception associated with PTSD. Deficits in safety learning may increase fear and, consequently, pain sensations. These findings may contribute to elucidating the pathogenesis behind the highly prevalent comorbidity that exists between PTSD and pain disorders, and to developing new treatments. This study provides new insights into the pathogenesis of chronic pain in patients with PTSD. The findings may help to develop new treatment strategies for this highly prevalent comorbidity in PTSD. Copyright © 2016 American Pain Society. All rights reserved.

Young people's experiences of persistent musculoskeletal pain, needs, gaps and perceptions about the role of digital technologies to support their co-care: a qualitative study

PubMed Central

Jordan, Joanne E; Chua, Jason; Schütze, Robert; Wark, John D

2016-01-01

Objective To investigate young people's experiences of persistent musculoskeletal pain, including care needs and current service gaps as well as perceptions about the role of digital technologies to support their co-care. Methods A qualitative study employing two independent data collection modes: in-depth individual semistructured interviews and focus groups. Setting Community settings throughout Australia. Participants Participants were included if they had experienced persistent musculoskeletal pain of >3-month duration with an average of ≥3 on the visual analogue scale over the preceding 3 months, including non-specific conditions (eg, low back pain) and specific conditions (eg, juvenile idiopathic arthritis and other systemic arthritides), with/without pre-existing or current diagnosed mental health conditions. 23 young people (87.0% women; mean (SD) age: 20.8 (2.4) years) from across 6 Australian jurisdictions participated. Almost two-thirds of participants with persistent musculoskeletal pain reported comorbid mental health conditions. Main outcome measures Inductive and deductive approaches to analyse and derive key themes from verbatim transcripts. Results Participants described their daily experiences of living with persistent musculoskeletal pain, their fears and the challenges imposed by the invisibility of pain, and the two-way relationship between their pain and mental well-being. A lack of relevant and accessible information and resources tailored to young people's unique needs, integrated and youth-relevant healthcare services and adequately skilled healthcare practitioners were identified as key care gaps. Participants strongly advocated for the use of digital technologies to improve access to age-appropriate resources and support for co-care. Conclusions Young people living with persistent musculoskeletal pain described the absence of age-appropriate pain services and clearly articulated their perceptions on the role of, and opportunities provided by, digital technologies to connect with and support improved pain healthcare. Innovative and digitally-enabled models of pain care are likely to be helpful for this group. PMID:27940635

Understanding patient perspectives on management of their chronic pain - online survey protocol.

PubMed

Gaikwad, Manasi; Vanlint, Simon; Moseley, G Lorimer; Mittinty, Murthy N; Stocks, Nigel

2017-01-01

It is widely recognized that both doctors and patients report discontent regarding pain management provided and received. The impact of chronic pain on an individual's life resonates beyond physical and mental suffering; equal or at times even greater impact is observed on an individual's personal relationships, ability to work, and social interactions. The degree of these effects in each individual varies, mainly because of differences in biological factors, social environment, past experiences, support, and belief systems. Therefore, it is equally possible that these individual patient characteristics could influence their treatment outcome. Research shows that meeting patient expectations is a major challenge for health care systems attempting to provide optimal treatment strategies. However, patient perspectives and expectations in chronic pain management have not been studied extensively. The aim of this study is to investigate the views, perceptions, beliefs, and expectations of individuals who experience chronic pain on a daily basis, and the strategies used by them in managing chronic pain. This paper describes the study protocol to be used in a cross sectional survey of chronic pain patients. The study population will comprise of individuals aged ≥18 years, who have experienced pain for ≥3 months with no restrictions of sex, ethnicity, or region of residence. Ethics approval for our study was obtained from Humans research ethics committees, University of Adelaide and University of South Australia. Multinomial logistic regression will be used to estimate the effect of duration and character of pain, on patient's perception of time to recovery and supplement intake. Logistic regression will also be used for estimating the effect of patient-provider relationship and pain education on patient-reported recovery and pain intensity. Knowledge about the perceptions and beliefs of patients with chronic pain could inform future policies, research, health care professional education, and development of individualized treatment strategies.

Pain in People With Alzheimer Disease: Potential Applications for Psychophysical and Neurophysiological Research

PubMed Central

Monroe, Todd B.; Gore, John C.; Chen, Li Min; Mion, Lorraine C.; Cowan, Ronald L.

2015-01-01

Pain management in people with dementia is a critical problem. Recently, psychophysical and neuroimaging techniques have been used to extend our understanding of pain processing in the brain as well as to identify structural and functional changes in Alzheimer disease (AD). But interpreting the complex relationship between AD pathology, brain activation, and pain reports is challenging. This review proposes a conceptual framework for designing and interpreting psychophysical and neuroimaging studies of pain processing in people with AD. Previous human studies describe the lateral (sensory) and medial (affective) pain networks. Although the majority of the literature on pain supports the lateral and medial networks, some evidence supports an additional rostral pain network, which is believed to function in the production of pain behaviors. The sensory perception of pain as assessed through verbal report and behavioral display may be altered in AD. In addition, neural circuits mediating pain perception and behavioral expression may be hyperactive or underactive, depending on the brain region involved, stage of the disease, and type of pain (acute experimental stimuli or chronic medical conditions). People with worsening AD may therefore experience pain but be unable to indicate pain through verbal or behavioral reports, leaving them at great risk of experiencing untreated pain. Psychophysical (verbal or behavioral) and neurophysiological (brain activation) approaches can potentially address gaps in our knowledge of pain processing in AD by revealing the relationship between neural processes and verbal and behavioral outcomes in the presence of acute or chronic pain. PMID:23277361

Coherent modulation of stimulus colour can affect visually induced self-motion perception.

PubMed

Nakamura, Shinji; Seno, Takeharu; Ito, Hiroyuki; Sunaga, Shoji

2010-01-01

The effects of dynamic colour modulation on vection were investigated to examine whether perceived variation of illumination affects self-motion perception. Participants observed expanding optic flow which simulated their forward self-motion. Onset latency, accumulated duration, and estimated magnitude of the self-motion were measured as indices of vection strength. Colour of the dots in the visual stimulus was modulated between white and red (experiment 1), white and grey (experiment 2), and grey and red (experiment 3). The results indicated that coherent colour oscillation in the visual stimulus significantly suppressed the strength of vection, whereas incoherent or static colour modulation did not affect vection. There was no effect of the types of the colour modulation; both achromatic and chromatic modulations turned out to be effective in inhibiting self-motion perception. Moreover, in a situation where the simulated direction of a spotlight was manipulated dynamically, vection strength was also suppressed (experiment 4). These results suggest that observer's perception of illumination is critical for self-motion perception, and rapid variation of perceived illumination would impair the reliabilities of visual information in determining self-motion.

Priors in perception: Top-down modulation, Bayesian perceptual learning rate, and prediction error minimization.

PubMed

Hohwy, Jakob

2017-01-01

I discuss top-down modulation of perception in terms of a variable Bayesian learning rate, revealing a wide range of prior hierarchical expectations that can modulate perception. I then switch to the prediction error minimization framework and seek to conceive cognitive penetration specifically as prediction error minimization deviations from a variable Bayesian learning rate. This approach retains cognitive penetration as a category somewhat distinct from other top-down effects, and carves a reasonable route between penetrability and impenetrability. It prevents rampant, relativistic cognitive penetration of perception and yet is consistent with the continuity of cognition and perception. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of pre-cooling injection site on pain perception in pediatric dentistry: “A randomized clinical trial”

PubMed Central

Ghaderi, Faezeh; Banakar, Shahin; Rostami, Shima

2013-01-01

Background: Injection of local anesthesia is one of the most important reasons for development of avoidance behavior in children. Efforts have been performed to decrease pain perception of injection. The present research evaluated the effect of cooling the injection site on pain perception before infiltration of local anesthetics. Materials and Methods: A prospective single-blind crossover clinical trial was used to investigate pain perception in 50 healthy pediatric patients who needed bilateral buccal infiltration of local anesthetics for dental treatment. They received a topical anesthetic agent (Benzocaine) on one side (control) for 1 min and topical anesthetic agent plus one minute of ice pack on the other side (trial) prior to the injection. A dentist blind to the study assessed the patients’ reaction during injection. Wilcoxon and Mann-Whitney U tests were used for statistical analysis. Statistical significance was defined at P < 0.05. Results: The means of sound, eye, and motor scales (SEM) were 4.06 ± 1.32 and 5.44 ± 1.79 for the study and control groups, respectively. The means of visual analogue scales (VAS) for the study and control groups were 42.20 ± 12.70 and 58.40 ± 16.83, respectively; with statistically significant differences between the two groups (P < 0.05). Conclusion: Cooling the injection site before infiltration of local anesthetics in the buccal mucosa for 1 min, reduced pain perceived by pediatric patients. PMID:24379869

Action preparation modulates sensory perception in unseen personal space: An electrophysiological investigation.

PubMed

Job, Xavier E; de Fockert, Jan W; van Velzen, José

2016-08-01

Behavioural and electrophysiological evidence has demonstrated that preparation of goal-directed actions modulates sensory perception at the goal location before the action is executed. However, previous studies have focused on sensory perception in areas of peripersonal space. The present study investigated visual and tactile sensory processing at the goal location of upcoming movements towards the body, much of which is not visible, as well as visible peripersonal space. A motor task cued participants to prepare a reaching movement towards goals either in peripersonal space in front of them or personal space on the upper chest. In order to assess modulations of sensory perception during movement preparation, event-related potentials (ERPs) were recorded in response to task-irrelevant visual and tactile probe stimuli delivered randomly at one of the goal locations of the movements. In line with previous neurophysiological findings, movement preparation modulated visual processing at the goal of a movement in peripersonal space. Movement preparation also modulated somatosensory processing at the movement goal in personal space. The findings demonstrate that tactile perception in personal space is subject to similar top-down sensory modulation by motor preparation as observed for visual stimuli presented in peripersonal space. These findings show for the first time that the principles and mechanisms underlying adaptive modulation of sensory processing in the context of action extend to tactile perception in unseen personal space. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modulation of pain by estrogens.

PubMed

Craft, Rebecca M

2007-11-01

It has become increasingly apparent that women suffer a disproportionate amount of pain during their lifetime compared to men. Over the past 15 years, a growing number of studies have suggested a variety of causes for this sex difference, from cellular to psychosocial levels of analysis. From a biological perspective, sexual differentiation of pain appears to occur similarly to sexual differentiation of other phenomena: it results in large part from organizational and activational effects of gonadal steroid hormones. The focus of this review is the activational effects of a single group of ovarian hormones, the estrogens, on pain in humans and animals. The effects of estrogens (estradiol being the most commonly examined) on experimentally induced acute pain vs. clinical pain are summarized. For clinical pain, the review is limited to a few syndromes for which there is considerable evidence for estrogenic involvement: migraine, temporomandibular disorder (TMD) and arthritis. Because estrogens can modulate the function of the nervous, immune, skeletal, and cardiovascular systems, estrogenic modulation of pain is an exceedingly complex, multi-faceted phenomenon, with estrogens producing both pro- and antinociceptive effects that depend on the extent to which each of these systems of the body is involved in a particular type of pain. Forging a more complete understanding of the myriad ways that estrogens can ameliorate vs. facilitate pain will enable us to better prevent and treat pain in both women and men.

Optogenetic exploration and modulation of pain processing.

PubMed

Xie, Yu-Feng; Wang, Jing; Bonin, Robert P

2018-08-01

Intractable pain is the single most common cause of disability, affecting more than 20% of the population world-wide. There is accordingly a global effort to decipher how changes in nociceptive processing in the peripheral and central nervous systems contribute to the onset and maintenance of chronic pain. The past several years have brought rapid progress in the adaptation of optogenetic approaches to study and manipulate the activity of sensory afferents and spinal cord neurons in freely behaving animals, and to investigate cortical processing and modulation of pain responses. This review discusses methodological advances that underlie this recent progress, and discusses practical considerations for the optogenetic modulation of nociceptive sensory processing. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

Psychological interventions influence patients' attitudes and beliefs about their chronic pain.

PubMed

Vanhaudenhuyse, Audrey; Gillet, Aline; Malaise, Nicole; Salamun, Irène; Grosdent, Stéphanie; Maquet, Didier; Nyssen, Anne-Sophie; Faymonville, Marie-Elisabeth

2018-04-01

Patients' changing attitudes and beliefs about pain are considered as improvements in the treatment of chronic pain. Multidisciplinary approaches to pain allow modifications of coping strategies of patients, from passive to active. We investigate how two therapeutic treatments impact patients' attitudes and beliefs regarding pain, as measured with the Survey of Pain Attitudes (SOPA). We allocated 415 patients with chronic pain either to psychoeducation combined with physiotherapy, self-hypnosis combined with self-care learning, or to control groups. Pain intensity, global impression of change, and beliefs and attitudes regarding pain were assessed before and after treatment. Our main results showed a significant effect of psychoeducation/physiotherapy on control, harm, and medical cure SOPA subscales; and a significant effect of self-hypnosis/self-care on control, disability and medical cure subscales. Correlation results showed that pain perception was negatively associated with control, while positively associated with disability, and a belief that hurt signifies harm. Patients' impression of improvement was associated with greater control, lower disability, and lower belief that hurt signifies harm. The present study showed that self-hypnosis/self-care and psychoeducation/physiotherapy were associated with patients' evolution of coping strategies from passive to active, allowing them to reduce pain perception and improve their global impression of treatment effectiveness.

[Mirror therapy for inflammatory rheumatic pain: Potentials and limitations].

PubMed

Bekrater-Bodmann, R

2015-11-01

Mirror therapy reduces chronic pain and might also be suitable for the treatment of inflammatory rheumatic pain. On the basis of the relevant literature this article a) characterizes the universal alterations in body perception and body representation in chronic pain, b) describes the potential mechanisms underlying mirror therapy and c) discusses the chances of success of mirror therapy for the treatment of inflammatory rheumatic pain. Literature search on the effectiveness and mechanisms of mirror therapy and derived procedures for the potential treatment of pain in inflammatory rheumatic disorders. There is evidence that mirror therapy can alleviate chronic pain experiences by correcting the accompanying distorted body perception as well as body representation by multimodal sensory stimulation. As there is probably a similar distortion in persons with chronic pain related to inflammatory rheumatic disorders, mirror therapy might also have positive effects in this field; however, the accompanying characteristics of these disorders, such as motor impairment and motor-evoked pain, may complicate the implementation of this kind of treatment. Mirror therapy represents an intervention with few side effects and might have positive effects on the experience of chronic pain in patients with inflammatory rheumatic disorders. Further clinical research is required in order to evaluate the potential of mirror therapy and associated interventional methods for the treatment of inflammatory rheumatic pain.

The effects of physical training without equipment on pain perception and balance in the elderly: A randomized controlled trial.

PubMed

Patti, Antonino; Bianco, Antonino; Karsten, Bettina; Montalto, Maria Alessandra; Battaglia, Giuseppe; Bellafiore, Marianna; Cassata, Daniela; Scoppa, Fabio; Paoli, Antonio; Iovane, Angelo; Messina, Giuseppe; Palma, Antonio

2017-01-01

Research supports a link between exercise and falls prevention in the older population. Our aims were to evaluate pain perception and balance skills in a group of elderly subjects and to examine the consequences of a standardized equipment-free exercise program intervention on these variables. The study utilized a randomized controlled trial method. 92 subjects were recruited from a rural Sicilian village (Resuttano, Sicily, Italy). Subjects were randomly split into two groups, an experimental group (EG; n = 49) and a control group (CG; n = 43). Qualified fitness instructors delivered the standardized physical exercise program for the EG whilst the CG did not receive this exercise intervention. The Berg Balance Scale and the Oswestry Disability Index were administered in both groups before (T0) and after the intervention (T1). At T1, the EG group significantly improvement in balance (p < 0.0001) and pain perception (p < 0.0001). No significant differences were found within the CG both in BBS and ODI, respectively. Our findings suggest that a 13-weeks standardized exercise equipment-free program is effective in improving balance and perception of pain in the elderly. This type of intervention can consequently provide a low cost strategy to counteract the rate of disability in elderly.

Audiovisual distraction reduces pain perception during aural microsuction.

PubMed

Choudhury, N; Amer, I; Daniels, M; Wareing, M J

2013-01-01

Aural microsuction is a common ear, nose and throat procedure used in the outpatient setting. Some patients, however, find it difficult to tolerate owing to discomfort, pain or noise. This study evaluated the effect of audiovisual distraction on patients' pain perception and overall satisfaction. A prospective study was conducted for patients attending our aural care clinic requiring aural toileting of bilateral mastoid cavities over a three-month period. All microsuction was performed by a single clinical nurse specialist. Any patients with active infection were excluded. For each patient, during microsuction of one ear, they watched the procedure on a television screen while for the other ear they did not view the procedure. All patients received the same real time explanations during microsuction of both ears. After the procedure, each patient completed a visual analogue scale (VAS) to rate the pain they experienced for each ear, with and without access to the television screen. They also documented their preference and reasons why. A total of 37 patients were included in the study. The mean pain score for patients viewing the procedure was 2.43 compared with a mean of 3.48 for patients with no television view. This difference in patients' pain perception was statistically lower in the group who observed the procedure on the television (p=0.003), consistent with the majority of patients reporting a preference to viewing their procedure (65%). Audiovisual distraction significantly lowered patients' VAS pain scores during aural microsuction. This simple intervention can therefore reduce patients' perceived pain and help improve acceptance of this procedure.

Barriers to pediatric pain management: a nursing perspective.

PubMed

Czarnecki, Michelle L; Simon, Katherine; Thompson, Jamie J; Armus, Cheryl L; Hanson, Tom C; Berg, Kristin A; Petrie, Jodie L; Xiang, Qun; Malin, Shelly

2011-09-01

This study describes strategies used by the Joint Clinical Practice Council of Children's Hospital of Wisconsin to identify barriers perceived as interfering with nurses' (RNs) ability to provide optimal pain management. A survey was used to ascertain how nurses described optimal pain management and how much nurses perceived potential barriers as interfering with their ability to provide that level of care. The survey, "Barriers to Optimal Pain management" (adapted from Van Hulle Vincent & Denyes, 2004), was distributed to all RNs working in all patient care settings. Two hundred seventy-two surveys were returned. The five most significant barriers identified were insufficient physician (MD) orders, insufficient MD orders before procedures, insufficient time to premedicate patients before procedures, the perception of a low priority given to pain management by medical staff, and parents' reluctance to have patients receive pain medication. Additional barriers were identified through narrative comments. Information regarding the impact of the Acute Pain Service on patient care, RNs' ability to overcome barriers, and RNs' perception of current pain management practices is included, as are several specific interventions aimed at improving or ultimately eliminating identified barriers. Copyright © 2011 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Neurophysiology and functional neuroanatomy of pain perception.

PubMed

Schnitzler, A; Ploner, M

2000-11-01

The traditional view that the cerebral cortex is not involved in pain processing has been abandoned during the past decades based on anatomic and physiologic investigations in animals, and lesion, functional neuroimaging, and neurophysiologic studies in humans. These studies have revealed an extensive central network associated with nociception that consistently includes the thalamus, the primary (SI) and secondary (SII) somatosensory cortices, the insula, and the anterior cingulate cortex (ACC). Anatomic and electrophysiologic data show that these cortical regions receive direct nociceptive thalamic input. From the results of human studies there is growing evidence that these different cortical structures contribute to different dimensions of pain experience. The SI cortex appears to be mainly involved in sensory-discriminative aspects of pain. The SII cortex seems to have an important role in recognition, learning, and memory of painful events. The insula has been proposed to be involved in autonomic reactions to noxious stimuli and in affective aspects of pain-related learning and memory. The ACC is closely related to pain unpleasantness and may subserve the integration of general affect, cognition, and response selection. The authors review the evidence on which the proposed relationship between cortical areas, pain-related neural activations, and components of pain perception is based.

Dissociable influences of opiates and expectations on pain

PubMed Central

Atlas, Lauren Y.; Whittington, Robert A.; Lindquist, Martin A.; Wielgosz, Joe; Sonty, Nomita; Wager, Tor D.

2012-01-01

Placebo treatments and opiate drugs are thought to have common effects on the opioid system and pain-related brain processes. This has created excitement about the potential for expectations to modulate drug effects themselves. If drug effects differ as a function of belief, this would challenge the assumptions underlying the standard clinical trial. We conducted two studies to directly examine the relationship between expectations and opioid analgesia. We administered the opioid agonist remifentanil to human subjects during experimental thermal pain and manipulated participants’ knowledge of drug delivery using an open-hidden design. This allowed us to test drug effects, expectancy (knowledge) effects, and their interactions on pain reports and pain-related responses in the brain. Remifentanil and expectancy both reduced pain, but drug effects on pain reports and fMRI activity did not interact with expectancy. Regions associated with pain processing showed drug-induced modulation during both Open and Hidden conditions, with no differences in drug effects as a function of expectation. Instead, expectancy modulated activity in frontal cortex, with a separable time course from drug effects. These findings reveal that opiates and placebo treatments both influence clinically relevant outcomes and operate without mutual interference. PMID:22674280

Effect of Change in Position and Back Massage on Pain Perception during First Stage of Labor.

PubMed

Abdul-Sattar Khudhur Ali, Suad; Mirkhan Ahmed, Hamdia

2018-06-01

Labor is one of the most painful events in a women's life. Frequent change in positions and back massage may be effective in reducing pain during the first stage of labor. The focus of this study was to identify the impact of either change in position or back massage on pain perception during first stage of labor. A quasi-experimental study. Teaching hospital, Kurdistan Region, Iraq, November 2014 to October 2015. Eighty women were interviewed as a study sample when admitted to the labor and delivery area and divided into three groups: 20 women received frequent changes in position (group A), 20 women received back massage (Group B), and 40 women constituted the control group (group C). A structured interview questionnaire to collect background data was completed by the researcher in personal interviews with the mothers. The intervention was performed at three points in each group, and pain perception was measured after each intervention using the Face Pain Scale. The mean rank of the difference in pain scores among the study groups was as follows after the first, second, and third interventions, respectively: group A-52.33, 47.00, 49.2; group B-32.8, 30.28, 30.38; group C-38.44, 42.36, 41.21. There were significant differences between groups A, B, and C after the first, second, and third interventions (p 1  = .011, p 2  = .042, p 3  = .024). Back massage may be a more effective pain management approach than change in position during the first stage of labor. Copyright © 2018 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Effect of knee osteoarthritis on the perception of quality of life in Venezuelan patients.

PubMed

Chacón, José G; González, Nancy E; Véliz, Aleida; Losada, Benito R; Paul, Hernando; Santiago, Luís G; Antúnez, Ana; Finol, Yelitza; González, María E; Granados, Isabel; Maldonado, Irama; Maldonado, Teolinda; Marín, Francisco; Zambrano, Gisela; Rodríguez, Martín A

2004-06-15

To measure the perception of quality of life in Venezuelan patients with knee osteoarthritis and to identify those variables that may influence it. A multicenter, cross-sectional study of 126 mestizo patients with knee osteoarthritis recruited from 8 rheumatology centers in Venezuela. We used a Spanish-translated version of the Arthritis Impact Measurement Scales (AIMS), as adapted in Venezuela. One-way analysis of variance was used to compare the AIMS mean total score among subgroups of knee pain, anatomic stage, and socioeconomic status (SES); a post-hoc test was performed to identify significant intragroup differences. Pearson's correlation coefficient was used to examine correlations between age, body mass index (BMI), disease duration, knee pain, and AIMS score. Associations between radiologic stage, SES, and AIMS scores were examined using Spearman's rank correlation. Multiple regression analysis was used to estimate predictor factors of AIMS scores. A significant correlation was found between total AIMS scores and knee pain, age, and socioeconomic status, but not with BMI, disease duration, or anatomic stage. Patients with severe knee pain differed from those with mild and moderate pain, and the highest AIMS mean total score was seen in patients within the severe knee pain subset. Patients in the highest socioeconomic levels differed from those within lowest categories. Patients classified as being at the levels of relative and critical poverty showed the highest AIMS scores. Multiple regression analysis showed that knee pain was the only variable that exerted an independent effect on the quality of life in our patients. The perception of quality of life is negatively affected by increasing levels of joint pain, old age, and low socioeconomic status in Venezuelan patients with knee osteoarthritis. Our study supports the need for an early and vigorous approach to treat pain in this group of patients.

Parental involvement in neonatal pain management: an empirical and conceptual update.

PubMed

Franck, Linda S; Oulton, Kate; Bruce, Elizabeth

2012-03-01

New findings are emerging about parental perceptions and desires for involvement in infant pain management in the neonatal intensive care unit (NICU) setting, and the importance of building greater knowledge about this aspect of the patient care is beginning to be appreciated. The study had two aims: (a) to describe perceptions and feelings of parents who participated in a randomized controlled trial of an intervention to increase parent knowledge and involvement in infant pain management; and (b) to further refine the conceptual representation of the parental experience of involvement in infant pain management (or lack thereof) and the influencing factors. Thematic analysis was used to explore the content of parents' written comments and to integrate the present and previous research findings. Parents expressed strong preferences for more information about all aspects of infant pain care, improved timing of information giving, and involvement opportunities. They further desired increased sensitivity and consistency in infant care giving and increased use of specific pain-relieving interventions by NICU staff. Contextual factors such as parents' emotional state and the communication and support from NICU staff influenced parents' ability to achieve their desired level of involvement. The role of parents in infant pain management is a relatively new area of research. The discussion of conceptual models to guide research and practice is an important milestone representing new opportunity for further scientific developments with important clinical implications for the nursing care of critically ill infants and their families. New data continue to emerge about parental perceptions and desires for involvement in infant pain management. A new empirically based model may be useful to nurses in providing optimal pain management for NICU infants in partnership with parents. © 2012 Sigma Theta Tau International.

Emergency Department Patient Perceptions of Transvaginal Ultrasound for Complications of First-Trimester Pregnancy.

PubMed

Panebianco, Nova; Shofer, Frances; O'Conor, Katie; Wihbey, Tristan; Mulugeta, Lakeisha; Baston, Cameron M; Suzuki, Evan; Alghamdi, Adel; Dean, Anthony

2018-01-30

Emergency department (ED) transvaginal ultrasound (US) is underused in clinical practice. This study assessed pregnant women's perceptions of ED transvaginal US in terms of pain, embarrassment, anxiety, and willingness to receive the procedure. Secondary variables include physicians' perceptions of patients' experiences. Women undergoing US examinations for complications of first-trimester pregnancy were prospectively surveyed before any US and after ED and/or radiology transvaginal US. Patients' and physicians' assessments of pain, embarrassment, and anxiety were measured with visual analog scales (0-100). A total of 398 women were enrolled. In the pre-US survey, the median anxiety score was 14 (interquartile range, 3-51), and 96% of patients were willing to have an ED transvaginal US if necessary. Of those who had ED transvaginal US, 96% would agree to have another examination. Patients reported minimal pain/embarrassment, and there was no difference if performed in the ED versus radiology (median pain, 11.5 versus 13; P = .433; median embarrassment, 7 versus 4; P = .345). Of the 48 who had both ED and radiology transvaginal US, 85% thought the ED transvaginal US was worthwhile. Physicians accurately assessed patient's embarrassment and pain (mean differences, 3.5 and -1.9, respectively; P > .25 for both); however, they overestimated them relative to the pelvic examination (mean difference for embarrassment, 12.8; P < .0001; pain, 8.0; P = .01). Pregnant ED patients report low levels of anxiety, pain, and embarrassment, and after ED transvaginal US, 96% would agree to have the examination again. There is no difference in pain/embarrassment between ED and radiology transvaginal US. Emergency department physicians accurately assessed patients' pain and embarrassment with ED transvaginal US but overestimated them compared to the pelvic examination. © 2018 by the American Institute of Ultrasound in Medicine.

Lipid modulation of thermal transient receptor potential channels.

PubMed

Hernández-García, Enrique; Rosenbaum, Tamara

2014-01-01

There is a subgroup of transient receptor potential (TRP) ion channels that are responsive to temperature (thermo-TRP channels). These are important to a variety of sensory and physiological phenomena such as pain and taste perception. All thermo-TRP channels known to date are subject to modulation by lipidic molecules of many kinds, from the ubiquitous cholesterol to more specialized molecules such as prostaglandins. Although the mechanisms and sites of binding of lipids on thermo-TRPs are largely unknown, the explosion on research of lipids and ion channels has revealed previously unsuspected roles for them. Diacyl glycerol is a lipid produced by phospholipase C (PLC) and it was discovered to modulate TRP channels in the eye of the fly, and many mammal TRP channels have been found to interact with lipids. While most of the lipids acting on thermo-TRP channels have been found to activate them, there are a few capable of inhibition. Phosphatidylinositol 4,5-bisphosphate is even capable of both inhibition and activation on a couple of thermo-TRPs, depending on the cellular context. More data is required to assess the mechanism through which lipids affect thermo-TRP channel activity and the physiological importance of this interaction.

Pain Management and Use of Opioids in Pediatric Oncology in India: A Qualitative Approach

PubMed Central

Boydell, Katherine M.; Breakey, Vicky; Kurkure, Purna A.; Muckaden, Marian A.; Bouffet, Eric; Arora, Brijesh

2017-01-01

Purpose Consumption of medical opium for pain relief in India is low, despite the country being one of the main world producers of the substance. We investigated obstacles to opioid use and physician perceptions about optimal pain management in pediatric oncology patients in India. Methods Semistructured interviews were conducted with oncologists who work in pediatric oncology settings. A mixed sampling strategy was used, including maximum variation and confirmation and disconfirmation of cases, as well as snowball sampling. Key informants were identified. Interviews were audio recorded, transcribed verbatim, and analyzed by thematic analysis methodology. Results Twenty-three interviews were performed across 20 Indian institutions. The main obstacles identified were lack of financial resources, inadequate education of health care providers on pain management, insufficient human resources (particularly lack of dedicated trained oncology nurses), poor access to opioids, and cultural perceptions about pain. Children from rural areas, treated in public hospitals, and from lower socioeconomic classes appear disadvantaged. A significant equality gap exists between public institutions and private institutions, which provide state-of-the-art treatment. Conclusion The study illuminates the complexity of pain management in pediatric oncology in India, where financial constraints, lack of education, and poor access to opioids play a dominant role, but lack of awareness and cultural perceptions about pain management among health care providers and parents emerged as important contributing factors. Urgent interventions are needed to optimize care in this vulnerable population. PMID:28831441

Association Between Allergies and Psychiatric Disorders in Patients Undergoing Invasive Procedures.

PubMed

Aberle, Dwight; Wu, Stephanie E; Oklu, Rahmi; Erinjeri, Joseph; Deipolyi, Amy R

Associations between allergies and psychiatric disorders have been reported in the context of depression and suicide; psychiatric disorders may affect pain perception. To investigate the relationship of allergies with psychiatric disorders and pain perception in the context of invasive procedures, specifically during tunneled hemodialysis catheter placement. We identified 89 patients (51 men, 38 women), mean age 66 years (range: 23-96), who underwent tunneled hemodialysis catheter placement (1/2014-2/2015), recording numeric rating scale pain scores, medications, psychiatric history, allergies, and smoking status. Of 89 patients, 47 patients had no allergies, and 42 had ≥1 allergy. Patients with allergies were more likely to have a pre-existing psychiatric disorder compared to those without allergies, odds ratio 2.6 (95% CI: 1.0-6.8). Having allergies did not affect procedural sedation or postprocedural pain scores. Multiple logistic regression with age, sex, smoking, presence of allergies, psychiatric history, inpatient/outpatient status, procedure time, and procedural sedation administration as inputs and postprocedural pain as the outcome showed that the only independent predictor was receiving procedural sedation (P = 0.005). Findings corroborate anecdotal reports of allergies as a marker for psychiatric history. However, having allergies was not associated with increased pain or need for more sedation. Further studies could prospectively assess whether allergies and psychiatric disorders affect patient/doctor perceptions beyond pain during invasive procedures. Copyright © 2017 The Academy of Psychosomatic Medicine. Published by Elsevier Inc. All rights reserved.

Perception and duration of pain after office-based vocal fold injection augmentation.

PubMed

Crawley, Brianna K; Dehom, Salem; Kutzner, Emily; Murry, Thomas; Krishna, Priya; Hata, Justin

2018-04-01

In-office laryngology procedures are important in the treatment of voice and swallowing disorders. Patient tolerance determines which procedures can be performed without sedation or formal anesthesia. This study examines pain perception during and after in-office vocal fold injection augmentation. Prospective cohort study. Patients scheduled for office-based vocal fold injection augmentation were prospectively enrolled at an academic voice center. The short-form McGill Pain Questionnaire was administered before, during, and after the procedure and on postprocedure days 1, 3, and 7. Pre- and postprocedure vital signs were recorded and heart rate was continuously monitored. Telephone questionnaires were completed on postprocedure days 1 and 3. Forty-five patients consented to participate in our study (24 males, mean age 61 years). Most patients experienced mild to moderate pain with increasing heart rate during the procedure. Pain remained or increased 20 minutes after the procedure and improved but persisted for 1 day. Sensory and affective discomfort was endorsed by the majority. A minority of patients experienced bruising and changes in swallowing with diet modification for 3 days after the procedure. Sixteen percent had discomfort after 1 week. This is the first prospective study examining patient perception of pain during and after in-office injection augmentation using a validated scale and pain descriptors with extended follow-up. The results may offer guidance for patient counseling, consent, and treatment to improve tolerance and success. 4. Laryngoscope, 128:929-934, 2018. © 2018 The American Laryngological, Rhinological and Otological Society, Inc.

Involvement of α2-adrenoceptors in inhibitory and facilitatory pain modulation processes.

PubMed

Vo, L; Drummond, P D

2016-03-01

In healthy humans, high-frequency electrical stimulation (HFS) of the forearm not only produces hyperalgesia at the site of stimulation but also reduces sensitivity to pressure-pain on the ipsilateral side of the forehead. In addition, HFS augments the ipsilateral trigeminal nociceptive blink reflex and intensifies the ipsilateral component of conditioned pain modulation. The aim of this study was to determine whether α2-adrenoceptors mediate these ipsilateral nociceptive influences. The α2-adrenoceptor antagonist yohimbine was administered to 22 participants in a double-blind, placebo-controlled crossover study. In each session, thermal and mechanical sensitivity in the forearms and forehead was assessed before and after HFS. In addition, the combined effect of HFS and yohimbine on the nociceptive blink reflex and on conditioned pain modulation was explored. In this paradigm, the conditioning stimulus was cold pain in the ipsilateral or contralateral temple, and the test stimulus was electrically evoked pain in the forearm. Blood pressure and electrodermal activity increased for several hours after yohimbine administration, consistent with blockade of central α2-adrenoceptors. Yohimbine not only augmented the nociceptive blink reflex ipsilateral to HFS but also intensified the inhibitory influence of ipsilateral temple cooling on electrically evoked pain at the HFS-treated site in the forearm. Yohimbine had no consistent effect on primary or secondary hyperalgesia in the forearm or on pressure-pain in the ipsilateral forehead. These findings imply involvement of α2-adrenoceptors both in ipsilateral antinociceptive and pronociceptive pain modulation processes. However, a mechanism not involving α2-adrenoceptors appears to mediate analgesia in the ipsilateral forehead after HFS. © 2015 European Pain Federation - EFIC®

Pain perception of children undergoing nasendoscopy for investigation of voice and resonance disorders.

PubMed

Hay, Imogen; Oates, Jennifer; Giannini, Alessandra; Berkowitz, Robert; Rotenberg, Brian

2009-05-01

The primary objective of this descriptive and correlational study was to determine the level of pain and discomfort perceived by children undergoing nasendoscopy for investigation of voice and resonance disorders. The secondary objective was to explore whether gender, age, previous experience of painful or distressing medical procedures, and previous experience of nasendoscopy influenced the perception of pain during nasendoscopy. Twenty-three children self-reported the degree of pain perceived during nasendoscopy using the Wong-Baker Faces Pain Rating Scale. Parents also used this scale to rate their child's perceived pain. Otolaryngologists and speech pathologists rated the intensity and frequency of observed pain-related behaviors using the Child-Adult Medical Procedure Interaction Scale-Revised and the Procedure Behavior Checklist. Children perceived the procedure, on average, to be moderately painful, as did their parents. Only two children reported perceiving no pain during the procedure. The most frequently observed pain-related behaviors were muscle tension (86.96%), physical resistance (69.57%), requiring physical restraint (60.87%), crying (43.48%), and expressions of verbal pain (39.13%). No significant correlations were found between self-reported pain or observed pain and the variables of age, gender, previous experience of nasendoscopy, and previous experience of painful or distressing medical procedures, although children aged 4-7 years reported significantly more pain than children aged 8-18 years. Most children perceive nasendoscopy to be painful to some degree. This perceived pain occurred in conjunction with several observable pain-related behaviors that have the potential to interfere with the success of the procedure.

Contextual modulation of pain sensitivity utilising virtual environments

PubMed Central

Smith, Ashley; Carlow, Klancy; Biddulph, Tara; Murray, Brooke; Paton, Melissa; Harvie, Daniel S

2017-01-01

Background: Investigating psychological mechanisms that modulate pain, such as those that might be accessed by manipulation of context, is of great interest to researchers seeking to better understand and treat pain. The aim of this study was to better understand the interaction between pain sensitivity, and contexts with inherent emotional and social salience – by exploiting modern immersive virtual reality (VR) technology. Methods: A within-subjects, randomised, double-blinded, repeated measures (RM) design was used. In total, 25 healthy participants were exposed to neutral, pleasant, threatening, socially positive and socially negative contexts, using an Oculus Rift DK2. Pressure pain thresholds (PPTs) were recorded in each context, as well as prior to and following the procedure. We also investigated whether trait anxiety and pain catastrophisation interacted with the relationship between the different contexts and pain. Results: Pressure pain sensitivity was not modulated by context (p = 0.48). Anxiety and pain catastrophisation were not significantly associated with PPTs, nor did they interact with the relationship between context and PPTs. Conclusion: Contrary to our hypothesis, socially and emotionally salient contexts did not influence pain thresholds. In light of other research, we suggest that pain outcomes might only be tenable to manipulation by contextual cues if they specifically manipulate the meaning of the pain-eliciting stimulus, rather than manipulate psychological state generally – as per the current study. Future research might exploit immersive VR technology to better explore the link between noxious stimuli and contexts that directly alter its threat value. PMID:28491299

Partners' Overestimation of Patients' Pain Severity: Relationships with Partners' Interpersonal Responses.

PubMed

Junghaenel, Doerte U; Schneider, Stefan; Broderick, Joan E

2017-09-26

The present study examined whether concordance between patients' and their partners' reports of patient pain severity relates to partners' social support and behavioral responses in couples coping with chronic pain. Fifty-two couples completed questionnaires about the patient's pain severity. Both dyad members also rated the partner's social support and negative, solicitous, and distracting responses toward the patient when in pain. Bivariate correlations showed moderate correspondence between patient and partner ratings of pain severity (r = 0.55) and negative (r = 0.46), solicitous (r = 0.47), and distracting responses (r = 0.53), but lower correspondence for social support (r = 0.28). Twenty-eight couples (54%) were concordant in their perceptions of patient pain; partners overestimated pain in 14 couples (27%), and partners underestimated pain in 10 couples (19%). Couple concordance in pain perceptions was not related to patients' reports; however, it significantly predicted partners' reports: Partners who overestimated pain reported giving more social support (β = 0.383, P = 0.016), fewer negative responses (β = -0.332, P = 0.029), and more solicitous responses (β = 0.438, P = 0.016) than partners who were in agreement or who underestimated pain. Partner overestimation of pain severity is associated with partner-reported but not with patient-reported support-related responses. This finding has important clinical implications for couple interventions in chronic pain. © 2017 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Night-shift work is associated with increased pain perception.

PubMed

Matre, Dagfinn; Knardahl, Stein; Nilsen, Kristian Bernhard

2017-05-01

Objectives The aim of the present study was to determine whether shift workers exhibit increased perception of experimentally induced pain after working night shifts. Methods The study was a paired cross-over design with two sleep conditions, after at least two nights of habitual sleep and after two consecutive night shifts at work. Fifty-three nurses in rotating shift work participated. The sensitivity to electrically induced pain, heat pain, cold pain, pressure pain and pain inhibition was determined experimentally in each sleep condition. Sleepiness and vigilance were also assessed. Results Night-shift work (NSW) increased the sensitivity to electrically induced pain and heat pain (P≤0.001). Relative to habitual sleep, electrically induced pain increased by 22.3% and heat pain increased by 26.5%. The sensitivity to cold and pressure pain did not change, changes relative to habitual sleep was <5% (P>0.5). Pain inhibition was 66.9% stronger after NSW versus after habitual sleep (P<0.001). Sleepiness (measured with the Karolinska Sleepiness Scale) increased from 4.1 after habitual sleep to 6.9 after NSW (P<0.001). Vigilance decreased after NSW, measured as a 0.03-second decrease in reaction time (P<0.005). Conclusions Changes in pain sensitivity after NSW is measurable with clinically relevant effect sizes and may be an important marker for studies comparing the physiological effects of different shift work schedules. Explanations for the differential effect on different pain modalities should be a focus for future studies.

Emotional Modulation of Interval Timing and Time Perception

PubMed Central

Lake, Jessica I.; LaBar, Kevin S.; Meck, Warren H.

2017-01-01

Like other senses, our perception of time is not veridical, but rather, is modulated by changes in environmental context. Anecdotal experiences suggest that emotions can be powerful modulators of time perception; nevertheless, the functional and neural mechanisms underlying emotion-induced temporal distortions remain unclear. Widely accepted pacemaker-accumulator models of time perception suggest that changes in arousal and attention have unique influences on temporal judgments and contribute to emotional distortions of time perception. However, such models conflict with current views of arousal and attention suggesting that current models of time perception do not adequately explain the variability in emotion-induced temporal distortions. Instead, findings provide support for a new perspective of emotion-induced temporal distortions that emphasizes both the unique and interactive influences of arousal and attention on time perception over time. Using this framework, we discuss plausible functional and neural mechanisms of emotion-induced temporal distortions and how these temporal distortions may have important implications for our understanding of how emotions modulate our perceptual experiences in service of adaptive responding to biologically relevant stimuli. PMID:26972824

The soothing function of touch: affective touch reduces feelings of social exclusion.

PubMed

von Mohr, Mariana; Kirsch, Louise P; Fotopoulou, Aikaterini

2017-10-18

The mammalian need for social proximity, attachment and belonging may have an adaptive and evolutionary value in terms of survival and reproductive success. Consequently, ostracism may induce strong negative feelings of social exclusion. Recent studies suggest that slow, affective touch, which is mediated by a separate, specific C tactile neurophysiological system than faster, neutral touch, modulates the perception of physical pain. However, it remains unknown whether slow, affective touch, can also reduce feelings of social exclusion, a form of social pain. Here, we employed a social exclusion paradigm, namely the Cyberball task (N = 84), to examine whether the administration of slow, affective touch may reduce the negative feelings of ostracism induced by the social exclusion manipulations of the Cyberball task. As predicted, the provision of slow-affective, as compared to fast-neutral, touch led to a specific decrease in feelings of social exclusion, beyond general mood effects. These findings point to the soothing function of slow, affective touch, particularly in the context of social separation or rejection, and suggest a specific relation between affective touch and social bonding.

Learned control over spinal nociception in patients with chronic back pain.

PubMed

Krafft, S; Göhmann, H-D; Sommer, J; Straube, A; Ruscheweyh, R

2017-10-01

Descending pain inhibition suppresses spinal nociception, reducing nociceptive input to the brain. It is modulated by cognitive and emotional processes. In subjects with chronic pain, it is impaired, possibly contributing to pain persistence. A previously developed feedback method trains subjects to activate their descending inhibition. Participants are trained to use cognitive-emotional strategies to reduce their spinal nociception, as quantified by the nociceptive flexor reflex (RIII reflex), under visual feedback about their RIII reflex size. The aim of the present study was to test whether also subjects with chronic back pain can achieve a modulation of their descending pain inhibition under RIII feedback. In total, 33 subjects with chronic back pain received either true (n = 18) or sham RIII feedback (n = 15), 15 healthy control subjects received true RIII feedback. All three groups achieved significant RIII suppression, largest in controls (to 76 ± 26% of baseline), intermediate in chronic back pain subjects receiving true feedback (to 82 ± 13%) and smallest in chronic back pain subjects receiving sham feedback (to 89 ± 14%, all p < 0.05). However, only chronic pain subjects receiving true feedback significantly improved their descending inhibition over the feedback training, quantified by the conditioned pain modulation effect (test pain reduction of baseline before training: to 98 ± 26%, after: to 80 ± 21%, p < 0.01). Our results show that subjects with chronic back pain can achieve a reduction of their spinal nociception and improve their descending pain inhibition under RIII feedback training. Subjects with chronic back pain can learn to control their spinal nociception, quantified by the RIII reflex, when they receive feedback about the RIII reflex. © 2017 European Pain Federation - EFIC®.

Development of force sensing circuit to determine the optimal force required for effective dynamic tripod grip/writing

NASA Astrophysics Data System (ADS)

Suraj S., S.; Kulkarni, Palash; Bokadia, Pratik; Ramanathan, Prabhu; Nageswaran, Sharmila

2018-04-01

Handwriting is a combination of fine motor perceptions and cognitive skills to produce words on paper. For writing, the most commonly used and recommended grip is the dynamic tripod grip. A child's handwriting starts developing during the times of pre-schooling and improves over time. While writing, children apply excessive force on the writing instrument. This force is exerted by their fingers and as per the law of reaction, the writing instruments tend to exert an equal and opposite force, that could damage the delicate soft tissue structures in their fingers and initiate cramps and pains. This condition is also prevalent in adults who tend to write for long hours under pressure. An example would be adolescence student during the exams. Clinically this condition is termed as `Writer's Cramp', which is usually characterized by muscle fatigue and pain in the fingers. By understanding and fixing the threshold of the force that should be exerted by the fingers while gripping the instrument, the pain can be controlled or avoided. This research aims in designing an electronic module which can help in understanding the threshold of pressure which is optimum enough to establish a better contact between the fingers and the instrument and should be capable of controlling or avoiding the pain. The design of FSR based electronic system is explained with its circuitry and results of initial testing is presented in this paper.

Motor imagery in spinal cord injured people is modulated by somatotopic coding, perspective taking, and post-lesional chronic pain.

PubMed

Scandola, Michele; Aglioti, Salvatore M; Pozeg, Polona; Avesani, Renato; Moro, Valentina

2017-09-01

Motor imagery (MI) allows one to mentally represent an action without necessarily performing it. Importantly, however, MI is profoundly influenced by the ability to actually execute actions, as demonstrated by the impairment of this ability as a consequence of lesions in motor cortices, limb amputations, movement limiting chronic pain, and spinal cord injury. Understanding MI and its deficits in patients with motor limitations is fundamentally important as development of some brain-computer interfaces and daily life strategies for coping with motor disorders are based on this ability. We explored MI in a large sample of patients with spinal cord injury (SCI) using a comprehensive battery of questionnaires to assess the ability to imagine actions from a first-person or a third-person perspective and also imagine the proprioceptive components of actions. Moreover, we correlated MI skills with personality measures and clinical variables such as the level and completeness of the lesion and the presence of chronic pain. We found that the MI deficits (1) concerned the body parts affected by deafferentation and deefferentation, (2) were present in first- but not in third-person perspectives, and (3) were more altered in the presence of chronic pain. MI is thus closely related to bodily perceptions and representations. Every attempt to devise tools and trainings aimed at improving autonomy needs to consider the cognitive changes due to the body-brain disconnection. © 2016 The British Psychological Society.

Hypnotic analgesia reduces brain responses to pain seen in others.

PubMed

Braboszcz, Claire; Brandao-Farinelli, Edith; Vuilleumier, Patrik

2017-08-29

Brain responses to pain experienced by oneself or seen in other people show consistent overlap in the pain processing network, particularly anterior insula, supporting the view that pain empathy partly relies on neural processes engaged by self-nociception. However, it remains unresolved whether changes in one's own pain sensation may affect empathic responding to others' pain. Here we show that inducing analgesia through hypnosis leads to decreased responses to both self and vicarious experience of pain. Activations in the right anterior insula and amygdala were markedly reduced when participants received painful thermal stimuli following hypnotic analgesia on their own hand, but also when they viewed pictures of others' hand in pain. Functional connectivity analysis indicated that this hypnotic modulation of pain responses was associated with differential recruitment of right prefrontal regions implicated in selective attention and inhibitory control. Our results provide novel support to the view that self-nociception is involved during empathy for pain, and demonstrate the possibility to use hypnotic procedures to modulate higher-level emotional and social processes.

The perception threshold counterpart to dynamic and static mechanical allodynia assessed using von Frey filaments in peripheral neuropathic pain patients.

PubMed

Landerholm, Åsa H; Hansson, Per T

2017-12-29

Background and aim Pain due to a usually non-painful mechanical stimulus, mechanical allodynia, is an oppressive symptom in subgroups of patients with neuropathic pain. Dynamic mechanical allodynia (DMA) is evoked by a normally innocuous light moving mechanical stimulus on the skin and static mechanical allodynia (SMA) by a sustained, normally innocuous pressure against the skin. DMA is claimed to be mediated by myelinated fibres and SMA by C-fibres. Also A-delta fibres have been implicated in the static subtype. A low intensity vertically applied stimulus of 1 second (s) is expected to activate predominantly rapidly adapting A-beta mechanoreceptors thus recruiting the same peripheral substrate as a horizontally moving brush on top of the skin. In patients with SMA we assumed an activation of Cbut also A-delta fibres from a static 10 s von Frey filament stimulus. The aim was to investigate if DMA and SMA could be assessed at perception threshold level using short or longer lasting usually non-painful von Frey filament prodding of the neuropathic skin. Patients and methods Eighteen patients with painful unilateral partial peripheral traumatic nerve injury suffering from SMA (n = 9) and/or DMA (n = 18) in a limb were studied. A compression/ischemia-induced (differential) nerve block in conjunction with repeated quantitative sensory testing of A-delta and C-fibre function using cold and warm stimuli was used to assess which nerve fibre population that contributes to pain at perception threshold level using 1 s (vF1) and 10 s (vF10) von Frey filament stimulation of the skin. Results The main outcome was the finding that elevation of vF1 and vF10 occurred simultaneously and significantly prior to an increase in the perception level to cold or warmth during the continuous nerve block. Single patients demonstrated a slight decrease in cold perception levels at the time of elevation of vF1 or vF10 and a possible contribution to mechanical allodynia from A-delta-fibres can therefore not completely be ruled out although the recorded alterations were minor. None of the patients reported an elevation of the perception level to warmth at the time of elevation of vF1 or vF10 excluding contribution from C-fibres. Further, only patients with clinically established SMA (n = 9) reported continuous pain to a sustained 10 s von Frey filament stimulation (vF10). Patients with only DMA (n = 9) reported pain merely for the initial 1-3 s of the total stimulus duration of 10 s and for a few seconds after the filament was lifted from the skin. Conclusions These findings support the role of A-beta fibres as peripheral mediators of both vF1 and vF10 although different receptor organs may be involved, i.e., rapidly (RA) and slowly (SA-I) adapting mechanoreceptors. Implications Techniques to quantify the different allodynias at perception threshold level deserve further attention as possible adjuncts to suprathreshold stimuli in intervention studies aimed at modifying these stimulus-evoked phenomena.

Progressive Muscle Relaxation and Pain Perception in Abdominal Surgery Patients

DTIC Science & Technology

1989-05-01

Twenty-one females were randomly assigned to one of three treatment groups: dental splint and physiotherapy , a relaxation program, or a minimal...overall treatment effect was average weekly frequency of pain (F = 5.25, p < .05). The relaxation and dental physiotherapy groups reported lower pain...significantly less pain intensity than the control group (TENS), while the dental/ physiotherapy group reported significantly less frequency of pain than

The influence of working memory capacity on experimental heat pain.

PubMed

Nakae, Aya; Endo, Kaori; Adachi, Tomonori; Ikeda, Takashi; Hagihira, Satoshi; Mashimo, Takashi; Osaka, Mariko

2013-10-01

Pain processing and attention have a bidirectional interaction that depends upon one's relative ability to use limited-capacity resources. However, correlations between the size of limited-capacity resources and pain have not been evaluated. Working memory capacity, which is a cognitive resource, can be measured using the reading span task (RST). In this study, we hypothesized that an individual's potential working memory capacity and subjective pain intensity are related. To test this hypothesis, we evaluated 31 healthy participants' potential working memory capacity using the RST, and then applied continuous experimental heat stimulation using the listening span test (LST), which is a modified version of the RST. Subjective pain intensities were significantly lower during the challenging parts of the RST. The pain intensity under conditions where memorizing tasks were performed was compared with that under the control condition, and it showed a correlation with potential working memory capacity. These results indicate that working memory capacity reflects the ability to process information, including precise evaluations of changes in pain perception. In this work, we present data suggesting that changes in subjective pain intensity are related, depending upon individual potential working memory capacities. Individual working memory capacity may be a phenotype that reflects sensitivity to changes in pain perception. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

Neonatal nurses' perceptions of pain management.

PubMed

Collados-Gómez, L; Camacho-Vicente, V; González-Villalba, M; Sanz-Prades, G; Bellón-Vaquerizo, B

To describe the perceptions of nurses in neonatal units on pain management, meet the educational profile and describe the use of pain assessment tools and non-pharmacological management for treatment. Cross-sectional descriptive multicentre study, developed during the months of February to September 2015, in the neonatology services of three hospitals at the Community of Madrid, Spain. Data collection was performed through an ad hoc questionnaire on paper or electronically using Survey Monkey platform. The sample consisted of 142 professionals, with a response rate of 55%: 47.9% (68) confirmed they had received specific training in pain management; 39.5% (56) stated that pain is regularly assessed in the unit; only 43.6% reported using validated scales, the most used being the Premature Infant Pain Profile (PIPP). As for the non-pharmacological management, swaddling and non-nutritive sucking it is the most used, followed by sucrose. Intravenous cannulation was identified as the most painful procedure. Pain management is in the process of improvement, because of training and because there is little pain assessment using validated scales. The improvement in the use of non-pharmacological management for the relief of pain in minor procedures is noteworthy. Copyright © 2017 Sociedad Española de Enfermería Intensiva y Unidades Coronarias (SEEIUC). Publicado por Elsevier España, S.L.U. All rights reserved.

Effect of Audioanalgesia in 6- to 12-year-old Children during Dental Treatment Procedure.

PubMed

Ramar, Kavitha; Hariharavel, V P; Sinnaduri, Gayathri; Sambath, Gayathri; Zohni, Fathima; Alagu, Palani J

2016-12-01

To evaluate the effect of audioanalgesia in 6- to 12-year-old children during dental treatment procedure. A total of 40 children were selected and divided into two groups, study group - with audioanalgesia and control group - without audioanalgesia. The value of their pain was evaluated using Venham's pain rating scale. Data were compared using one-sample t-test using Statistical Package for the Social Sciences (SPSS) (Inc.; Chicago, IL, USA), version 17.0. The difference in the control group and study group was statistically significant (p < 0.05). The method of distraction using audioanalgesia instills better positive dental attitude in children and decreases their pain perception. Playing or hearing music during dental procedure significantly alters the perception of pain in 6- to 12-year-old children.

Public perception of the terms "cosmetic," "plastic," and "reconstructive" surgery.

PubMed

Hamilton, Grant S; Carrithers, Jeffrey S; Karnell, Lucy H

2004-01-01

To investigate potential differences in perception of the terms "cosmetic," "plastic," and "reconstructive" as descriptors for surgery. An anonymous questionnaire was offered to subjects over 18 years of age throughout the Unites States via the Internet and in person. The multiple-choice survey measured variables including permanence, risk, expense, recovery, reversibility, pain, technical difficulty, and surgeon training. The questionnaire also included several open-ended questions to capture qualitative perceptions. Semantic differential data were analyzed to measure statistical significance. For most variables--permanence, risk, recovery, reversibility, pain, and surgeon training--the 216 subjects had significantly lower mean responses for cosmetic surgery than those for plastic or reconstructive surgery (P < .002). Overall, the results of this study support the authors' hypothesis that there is a significant difference in perception of cosmetic surgery and plastic or reconstructive surgery. Cosmetic surgery is perceived to be more temporary and less technically difficult than plastic or reconstructive surgery. In addition, cosmetic surgery is believed to be associated with less risk, shorter recovery time, and less pain. Subjects also thought that cosmetic surgeons required significantly less training than plastic or reconstructive surgeons.

Brain responses to vestibular pain and its anticipation in women with Genito-Pelvic Pain/Penetration Disorder.

PubMed

Pazmany, Els; Ly, Huynh Giao; Aerts, Leen; Kano, Michiko; Bergeron, Sophie; Verhaeghe, Johan; Peeters, Ronald; Tack, Jan; Dupont, Patrick; Enzlin, Paul; Van Oudenhove, Lukas

2017-01-01

In DSM-5, pain-related fear during anticipation of vaginal penetration is a diagnostic criterion of Genito-Pelvic Pain/Penetration Disorder (GPPPD). We aimed to investigate subjective and brain responses during anticipatory fear and subsequent induction of vestibular pain in women with GPPPD. Women with GPPPD (n = 18) and age-matched healthy controls (HC) (n = 15) underwent fMRI scanning during vestibular pain induction at individually titrated pain threshold after a cued anticipation period. (Pain-related) fear and anxiety traits were measured with questionnaires prior to scanning, and anticipatory fear and pain intensity were rated during scanning using visual analog scales. Women with GPPPD reported significantly higher levels of anticipatory fear and pain intensity. During anticipation and pain induction they had stronger and more extensive brain responses in regions involved in cognitive and affective aspects of pain perception, but the group difference did not reach significance for the anticipation condition. Pain-related fear and anxiety traits as well as anticipatory fear ratings were positively associated with pain ratings in GPPPD, but not in HC. Further, in HC, a negative association was found between anticipatory fear ratings and brain responses in regions involved in cognitive and affective aspects of pain perception, but not in women with GPPPD. Women with GPPPD are characterized by increased subjective and brain responses to vestibular pain and, to a lesser extent, its anticipation, with fear and anxiety associated with responses to pain, supporting the introduction of anticipatory fear as a criterion of GPPPD in DSM-5.

Ethnic differences in thermal pain responses: a comparison of South Asian and White British healthy males.

PubMed

Watson, Paul J; Latif, R Khalid; Rowbotham, David J

2005-11-01

The expression and report of pain is influenced by social environment and culture. Previous studies have suggested ethnically determined differences in report of pain threshold, intensity and affect. The influence of ethnic differences between White British and South Asians has remained unexplored. Twenty age-matched, male volunteers in each group underwent evaluation. Cold and warm perception and cold and heat threshold were assessed using an ascending method of limits. Magnitude estimation of pain unpleasantness and pain intensity were investigated with thermal stimuli of 46, 47, 48 and 49 degrees C. Subjects also completed a pain anxiety questionnaire. Data was analysed using t-test, Mann-Whitney and repeated measures analysis of variance as appropriate. There were no differences in cold and warm perception between the two groups. There was a statistically significant difference between the two groups for heat pain threshold (P=0.006) and heat pain intensity demonstrated a significant effect for ethnicity (F=13.84, P=0.001). Although no group differences emerged for cold pain threshold and heat unpleasantness, South Asians demonstrated lower cold pain threshold and reported more unpleasantness at all temperatures but this was not statistically significant. Our study shows that ethnicity plays an important role in heat pain threshold and pain report, South Asian males demonstrated lower pain thresholds and higher pain report when compared with matched White British males. There were no differences in pain anxiety between the two groups and no correlations were identified between pain and pain anxiety Haemodynamic measures and anthropometry did not explain group differences.

Objective evaluation of chemotherapy-induced peripheral neuropathy using quantitative pain measurement system (Pain Vision®), a pilot study.

PubMed

Sato, Junya; Mori, Megumi; Nihei, Satoru; Takeuchi, Satoshi; Kashiwaba, Masahiro; Kudo, Kenzo

2017-01-01

In an evaluation of chemotherapy-induced peripheral neuropathy (CIPN), objectivity may be poor because the evaluation is determined by the patient's subjective assessment. In such cases, management of neuropathy may be delayed and CIPN symptoms may become severe. In this pilot study, we attempted an objective evaluation of CIPN using a quantitative pain measurement system (Pain Vision ® ). The subjects were patients with gynecologic cancer who underwent chemotherapy using taxane and platinum drugs. The grade of the peripheral sensory nerve disorder was based on the Common Terminology Criteria for Adverse Events (CTC-AE) ver. 4.0 and was evaluated before the initiation of therapy and up to six chemotherapy cycles. A symptom scale assessed by the patients using a peripheral neuropathy questionnaire (PNQ) was also evaluated. Simultaneously during these evaluations, graded electric current was applied from the probe to a fingertip and measured both the lowest perceptible current and lowest current perceived as pain by Pain Vision ® . From these values, the pain degree was calculated from the following formula: (pain perception current value - lowest perceptible current value) ÷ lowest perceptible current value × 100. We compared the pain degrees by Pain Vision ® during CIPN development with the value obtained before chemotherapy initiation. Forty-one patients were enrolled. In the evaluation by a medical professional, 28 (64.3%) patients developed CIPN during 2.5 ± 1.1 chemotherapy cycles (mean ± standard deviation). The pain degree by Pain Vision ® at grade 1 and 2 CIPN development according to the evaluation (CTC-AE) was significantly decreased compared to that before chemotherapy initiation (126.0 ± 114.5 vs. 69.8 ± 46.8, p  = 0.001, and 126.0 ± 114.5 vs. 32.8 ± 32.6, p  = 0.004). Changes in the pain degree by Pain Vision ® were also found during scale B and C, D CIPN development in the patient evaluation (PNQ) (115.9 ± 112.4 vs. 70.6 ± 56.5, p  = 0.005, and 115.9 ± 112.4 vs. 46.3 ± 42.9, p  = 0.004). In the 13 patients in whom CIPN did not occur, no significant decrease in the pain degree by Pain Vision ® was detected ( p  = 0.764). There was no discontinuation of the measurements because of adverse events such as discomfort from the electric current. The decrease in the pain degree measured by Pain Vision ® was associated with the onset of CIPN symptoms. Particularly, detection of CIPN by Pain Vision ® was possible, though most of the CIPN that occurred was low grade or mild symptom. Pain Vision ® might become a noninvasive and convenient objective CIPN detection tool to supplement subjective CIPN evaluation. The study approval number in the institution; H25-140. Registered December 17, 2013.

[School bathrooms: children's perceptions and prevalence of gastrointestinal and urinary disorders, a survey in 3 secondary schools near Saint-Etienne].

PubMed

Hoarau, Bénédicte; Vercherin, Paul; Bois, Christophe

2014-01-01

Irregular use of toilets can contribute to urinary and gastrointestinal disorders. The aim of this study was to assess the prevalence of gastrointestinal and urinary symptoms among a secondary school teenage population and to evaluate their perception and use of school toilets. 791 adolescents aged 12 to 16 filled in an anonymous questionnaire, which was administered in three secondary schools near Saint-Etienne, France. 22% reported abdominal pain at least once a week during the past two months and 26% experienced abdominal pain about once every month. 9% of schoolchildren suffered from urinary incontinence at least once during the two months before the study: 4% of boys and 13% of girls. Children had a negative perception of school toilets: 62% didn't feel safe and 54% of boys reported a lack of privacy. 34% of students avoided school toilets: 21% never used them to urinate and 85% never used them to defecate. 28% of children acknowledged they had experienced abdominal pain because they couldn't use school toilets and 29% said that they had experienced poor concentration as a result of their pain. Abdominal pain and urinary disorders are common among secondary schoolchildren. Stool and urine withholding behaviours are be widespread and affect students' concentration while at school.

Emerging targets and therapeutic approaches for the treatment of osteoarthritis pain.

PubMed

Rahman, Wahida; Dickenson, Anthony H

2015-06-01

Osteoarthritis is a complex and often painful disease that is inadequately controlled with current analgesics. This review discusses emerging targets and therapeutic approaches that may lead to the development of better analgesics. Aberrant excitability in peripheral and central pain pathways drives osteoarthritis pain, reversing this via modulation of nerve growth factor, voltage-gated sodium channel, voltage-gated calcium channel and transient receptor potential vanilloid one activity, and increasing inhibitory mechanisms through modulation of cannabinoid and descending modulatory systems hold promise for osteoarthritis pain therapy. Somatosensory phenotyping of chronic pain patients, as a surrogate of putative pain generating mechanisms, may predict patient response to treatment. Identification of new targets will inform and guide future research, aiding the development of more effective analgesics. Future clinical trial designs should implement sensory phenotyping of patients, as an inclusion or stratification criterion, in order to establish an individualized, mechanism-based treatment of osteoarthritis pain.

Mindfulness meditation-related pain relief: Evidence for unique brain mechanisms in the regulation of pain

PubMed Central

Zeidan, F.; Grant, J.A.; Brown, C.A.; McHaffie, J.G.; Coghill, R.C.

2013-01-01

The cognitive modulation of pain is influenced by a number of factors ranging from attention, beliefs, conditioning, expectations, mood, and the regulation of emotional responses to noxious sensory events. Recently, mindfulness meditation has been found attenuate pain through some of these mechanisms including enhanced cognitive and emotional control, as well as altering the contextual evaluation of sensory events. This review discusses the brain mechanisms involved in mindfulness meditation-related pain relief across different meditative techniques, expertise and training levels, experimental procedures, and neuroimaging methodologies. Converging lines of neuroimaging evidence reveal that mindfulness meditation-related pain relief is associated with unique appraisal cognitive processes depending on expertise level and meditation tradition. Moreover, it is postulated that mindfulness meditation-related pain relief may share a common final pathway with other cognitive techniques in the modulation of pain. PMID:22487846

Effect of gender and hand laterality on pain processing in human neonates.

PubMed

Ozawa, Mio; Kanda, Katsuya; Hirata, Michio; Kusakawa, Isao; Suzuki, Chieko

2011-01-01

Previous studies in adults have reported that handedness and gender can affect pain perception. However, it is currently unclear when these differences emerge in human development. Therefore, we examined prefrontal responses to pain stimulation among newborns during their first acute pain experience after birth. Forty newborns at 4-6 days postnatal age were observed during clinically required blood sampling while prefrontal activation was measured with near infrared spectroscopy. Blood sampling in this study was the first experience of a procedure involving skin breaking for these infants. We divided subjects into a right-hand stimulation group (n=21) and a left-hand stimulation group (n=19), depending on whether blood was sampled from the right or the left hand. A three-way analysis of variance (ANOVA) was conducted to examine the effects of several variables on the magnitude of the oxy-Hb value in response to pain stimulus, including stimulus side (right hand or left hand), gender (male or female), recording side (right prefrontal area or left prefrontal area) and interactions between these variables. The data revealed a significant effect of stimulus side (F (1, 72)=9.892, P=0.002), showing that the right-hand stimulation induced a greater prefrontal activation than the left-hand stimulation. No significant gender difference or interactions were found. Our findings suggest that hand laterality affects pain perception even in neonates. However, gender differences in pain perception did not appear to occur during the neonatal period. Further investigations using brain-imaging techniques are required to identify laterality- or gender-related differences in pain processing in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Mechanistic experimental pain assessment in computer users with and without chronic musculoskeletal pain.

PubMed

Ge, Hong-You; Vangsgaard, Steffen; Omland, Øyvind; Madeleine, Pascal; Arendt-Nielsen, Lars

2014-12-06

Musculoskeletal pain from the upper extremity and shoulder region is commonly reported by computer users. However, the functional status of central pain mechanisms, i.e., central sensitization and conditioned pain modulation (CPM), has not been investigated in this population. The aim was to evaluate sensitization and CPM in computer users with and without chronic musculoskeletal pain. Pressure pain threshold (PPT) mapping in the neck-shoulder (15 points) and the elbow (12 points) was assessed together with PPT measurement at mid-point in the tibialis anterior (TA) muscle among 47 computer users with chronic pain in the upper extremity and/or neck-shoulder pain (pain group) and 17 pain-free computer users (control group). Induced pain intensities and profiles over time were recorded using a 0-10 cm electronic visual analogue scale (VAS) in response to different levels of pressure stimuli on the forearm with a new technique of dynamic pressure algometry. The efficiency of CPM was assessed using cuff-induced pain as conditioning pain stimulus and PPT at TA as test stimulus. The demographics, job seniority and number of working hours/week using a computer were similar between groups. The PPTs measured at all 15 points in the neck-shoulder region were not significantly different between groups. There were no significant differences between groups neither in PPTs nor pain intensity induced by dynamic pressure algometry. No significant difference in PPT was observed in TA between groups. During CPM, a significant increase in PPT at TA was observed in both groups (P < 0.05) without significant differences between groups. For the chronic pain group, higher clinical pain intensity, lower PPT values from the neck-shoulder and higher pain intensity evoked by the roller were all correlated with less efficient descending pain modulation (P < 0.05). This suggests that the excitability of the central pain system is normal in a large group of computer users with low pain intensity chronic upper extremity and/or neck-shoulder pain and that increased excitability of the pain system cannot explain the reported pain. However, computer users with higher pain intensity and lower PPTs were found to have decreased efficiency in descending pain modulation.

Social hierarchy modulates neural responses of empathy for pain

PubMed Central

Feng, Chunliang; Li, Zhihao; Feng, Xue; Wang, Lili; Tian, Tengxiang

2016-01-01

Recent evidence indicates that empathic responses to others’ pain are modulated by various situational and individual factors. However, few studies have examined how empathy and underlying brain functions are modulated by social hierarchies, which permeate human society with an enormous impact on social behavior and cognition. In this study, social hierarchies were established based on incidental skill in a perceptual task in which all participants were mediumly ranked. Afterwards, participants were scanned with functional magnetic resonance imaging while watching inferior-status or superior-status targets receiving painful or non-painful stimulation. The results revealed that painful stimulation applied to inferior-status targets induced higher activations in the anterior insula (AI) and anterior medial cingulate cortex (aMCC), whereas these empathic brain activations were significantly attenuated in response to superior-status targets’ pain. Further, this neural empathic bias to inferior-status targets was accompanied by stronger functional couplings of AI with brain regions important in emotional processing (i.e. thalamus) and cognitive control (i.e. middle frontal gyrus). Our findings indicate that emotional sharing with others’ pain is shaped by relative positions in a social hierarchy such that underlying empathic neural responses are biased toward inferior-status compared with superior-status individuals. PMID:26516169

Nurse Perceptions of Pain in Pediatric Traumatic Brain Injury: A Pilot Study.

PubMed

McCaa, Robin

2017-01-01

Pain assessment in the pediatric population is challenging because of age, developmental stage, and patient cooperation. Cognitive impairment, impaired communication, and physical disability that may accompany traumatic brain injury (TBI) further complicate pain assessments. A pilot descriptive qualitative research study was conducted to investigate nurse perceptions of pain in pediatric patients diagnosed with TBI. Specifically, this study sought to answer the following questions: a) Is pain accurately assessed in this population? b) Is pain adequately treated in this population? and c) What obstacles exist, if any, to the assessment and treatment of pain? A convenience sample of three registered nurses employed in a pediatric neurosurgery setting participated in this study. Each nurse participated in one individual, semi-structured, face-to-face interview lasting approximately 30 minutes. Interviews were transcribed verbatim and analyzed for common themes. Common themes identified across all interviews were a) challenging assessments; b) limited, although effective, treatments; and c) communication as an area of opportunity for improvement. Implications for practice and policy include a need for more sensitive pain assessment tools to improve the objectivity and accuracy of pain assessment, clarification of care priorities and organization of care from clinical and management perspectives, and additional research in alternative pain treatments for this population. Findings from this study will guide the development of a larger, more comprehensive study, with the aim of improving practice and policy in pain management for this population.

Perceptions of adults with overweight/obesity and chronic musculoskeletal pain: An interpretative phenomenological analysis.

PubMed

Cooper, Lesley; Ells, Louisa; Ryan, Cormac; Martin, Denis

2018-03-01

To gain insight into the lived experience of adults with overweight/obesity and chronic musculoskeletal pain. Knowledge gained will inform healthcare professionals about the complexity of the weight-pain relationship and enable more effective engagement with this population. Quantitative studies show links between weight and pain. Adults with overweight/obesity are more likely to experience comorbidity; however, qualitative research describing the complexities of the relationship is limited. A purposive sample of adults with overweight/obesity and chronic musculoskeletal pain participated in face-to-face interviews. Interviews were audio-recorded, transcribed verbatim and analysed using interpretive phenomenological analysis. Eighteen adults (16 female) aged 29-71, body mass index ≥25-46, participated in this study. Three superordinate themes emerged: "pain as a motivator and barrier to weight loss"; "fear of weight causing more damage"; and "activity is positive." Pain motivates some individuals to lose weight while simultaneously inhibiting weight loss efforts. Participants' perception that extra pressure caused by their weight further damaged joints contributed to fear and catastrophising. Fear is often exacerbated by healthcare professionals' descriptions of musculoskeletal damage, or participants' perception of healthcare professionals' attitude towards people with overweight/obesity. Conversely, individuals acknowledged the benefits of increased activity. Adults with overweight/obesity and chronic musculoskeletal pain in this study identified a bidirectional relationship between their weight and pain that challenged their weight loss efforts. Overweight/obesity contributed to fear and catastrophising, which resulted in avoidance of exercise that would have assisted their weight loss. Healthcare professionals need to understand the complex relationship between weight and pain, and their patients' understanding of that relationship. Healthcare professionals should use therapeutic communication to reduce the fear of weight causing damage, and thus promote physical activities that will contribute to weight loss. It is also important to ensure that the language used with this patient group does not stigmatise individuals, or cause or exacerbate fear of normal movement. © 2017 John Wiley & Sons Ltd.

Dynamic Neural State Identification in Deep Brain Local Field Potentials of Neuropathic Pain.

PubMed

Luo, Huichun; Huang, Yongzhi; Du, Xueying; Zhang, Yunpeng; Green, Alexander L; Aziz, Tipu Z; Wang, Shouyan

2018-01-01

In neuropathic pain, the neurophysiological and neuropathological function of the ventro-posterolateral nucleus of the thalamus (VPL) and the periventricular gray/periaqueductal gray area (PVAG) involves multiple frequency oscillations. Moreover, oscillations related to pain perception and modulation change dynamically over time. Fluctuations in these neural oscillations reflect the dynamic neural states of the nucleus. In this study, an approach to classifying the synchronization level was developed to dynamically identify the neural states. An oscillation extraction model based on windowed wavelet packet transform was designed to characterize the activity level of oscillations. The wavelet packet coefficients sparsely represented the activity level of theta and alpha oscillations in local field potentials (LFPs). Then, a state discrimination model was designed to calculate an adaptive threshold to determine the activity level of oscillations. Finally, the neural state was represented by the activity levels of both theta and alpha oscillations. The relationship between neural states and pain relief was further evaluated. The performance of the state identification approach achieved sensitivity and specificity beyond 80% in simulation signals. Neural states of the PVAG and VPL were dynamically identified from LFPs of neuropathic pain patients. The occurrence of neural states based on theta and alpha oscillations were correlated to the degree of pain relief by deep brain stimulation. In the PVAG LFPs, the occurrence of the state with high activity levels of theta oscillations independent of alpha and the state with low-level alpha and high-level theta oscillations were significantly correlated with pain relief by deep brain stimulation. This study provides a reliable approach to identifying the dynamic neural states in LFPs with a low signal-to-noise ratio by using sparse representation based on wavelet packet transform. Furthermore, it may advance closed-loop deep brain stimulation based on neural states integrating multiple neural oscillations.

Dynamic Neural State Identification in Deep Brain Local Field Potentials of Neuropathic Pain

PubMed Central

Luo, Huichun; Huang, Yongzhi; Du, Xueying; Zhang, Yunpeng; Green, Alexander L.; Aziz, Tipu Z.; Wang, Shouyan

2018-01-01

In neuropathic pain, the neurophysiological and neuropathological function of the ventro-posterolateral nucleus of the thalamus (VPL) and the periventricular gray/periaqueductal gray area (PVAG) involves multiple frequency oscillations. Moreover, oscillations related to pain perception and modulation change dynamically over time. Fluctuations in these neural oscillations reflect the dynamic neural states of the nucleus. In this study, an approach to classifying the synchronization level was developed to dynamically identify the neural states. An oscillation extraction model based on windowed wavelet packet transform was designed to characterize the activity level of oscillations. The wavelet packet coefficients sparsely represented the activity level of theta and alpha oscillations in local field potentials (LFPs). Then, a state discrimination model was designed to calculate an adaptive threshold to determine the activity level of oscillations. Finally, the neural state was represented by the activity levels of both theta and alpha oscillations. The relationship between neural states and pain relief was further evaluated. The performance of the state identification approach achieved sensitivity and specificity beyond 80% in simulation signals. Neural states of the PVAG and VPL were dynamically identified from LFPs of neuropathic pain patients. The occurrence of neural states based on theta and alpha oscillations were correlated to the degree of pain relief by deep brain stimulation. In the PVAG LFPs, the occurrence of the state with high activity levels of theta oscillations independent of alpha and the state with low-level alpha and high-level theta oscillations were significantly correlated with pain relief by deep brain stimulation. This study provides a reliable approach to identifying the dynamic neural states in LFPs with a low signal-to-noise ratio by using sparse representation based on wavelet packet transform. Furthermore, it may advance closed-loop deep brain stimulation based on neural states integrating multiple neural oscillations. PMID:29695951

Endogenous inhibition of pain and spinal nociception in women with premenstrual dysphoric disorder

PubMed Central

Palit, Shreela; Bartley, Emily J; Kuhn, Bethany L; Kerr, Kara L; DelVentura, Jennifer L; Terry, Ellen L; Rhudy, Jamie L

2016-01-01

Purpose Premenstrual dysphoric disorder (PMDD) is characterized by severe affective and physical symptoms, such as increased pain, during the late-luteal phase of the menstrual cycle. The mechanisms underlying hyperalgesia in women with PMDD have yet to be identified, and supraspinal pain modulation has yet to be examined in this population. The present study assessed endogenous pain inhibitory processing by examining conditioned pain modulation (CPM, a painful conditioning stimulus inhibiting pain evoked by a test stimulus at a distal body site) of pain and the nociceptive flexion reflex (NFR, a spinally-mediated withdrawal reflex) during the mid-follicular, ovulatory, and late-luteal phases of the menstrual cycle. Methods Participants were regularly-cycling women (14 without PMDD; 14 with PMDD). CPM was assessed by delivering electrocutaneous test stimuli to the sural nerve before, during, and after a painful conditioning ischemia task. Participants rated their pain to electrocutaneous stimuli, and NFR magnitudes were measured. A linear mixed model analysis was used to assess the influence of group and menstrual phase on CPM. Results Compared with controls, women with PMDD experienced greater pain during the late-luteal phase and enhanced spinal nociception during the ovulation phase, both of which were independent of CPM. Both groups showed CPM inhibition of pain that did not differ by menstrual phase. Only women with PMDD evidenced CPM inhibition of NFR. Conclusion Endogenous modulation of pain and spinal nociception is not disrupted in women with PMDD. Additionally, greater NFR magnitudes during ovulation in PMDD may be due to tonically-engaged descending mechanisms that facilitate spinal nociception, leading to enhanced pain during the premenstrual phase. PMID:26929663

Social stress exacerbates the aversion to painful experiences in rats exposed to chronic pain: the role of the locus coeruleus.

PubMed

Bravo, Lidia; Alba-Delgado, Cristina; Torres-Sanchez, Sonia; Mico, Juan Antonio; Neto, Fani L; Berrocoso, Esther

2013-10-01

Stressful experiences seem to negatively influence pain perception through as yet unknown mechanisms. As the noradrenergic locus coeruleus (LC) nucleus coordinates many components of the stress response, as well as nociceptive transmission, we evaluated whether the sensory and affective dimension of chronic neuropathic pain worsens in situations of stress due to adaptive changes of LC neurons. Accordingly, male rats were socially isolated for 5 weeks, and in the last 2 weeks, neuropathic pain was induced by chronic constriction injury. In this situation of stress, chronic pain selectively heightened the animal's aversion to painful experiences (affective pain), as measured in the place escape/avoidance test, although no changes were observed in the sensory dimension of pain. In addition, electrophysiological recordings of LC neurons showed a low tonic but exacerbated nociceptive-evoked activity when the injured paw was stimulated. These changes were accompanied by an increase in tyrosine hydroxylase and gephyrin expression in the LC. Furthermore, intra-LC administration of bicuculline, a γ-aminobutyric acid-A receptor antagonist, attenuated the negative affective effects of pain. These data show that changes in the LC are greater than those expected from the simple summation of each independent factor (pain and stress), revealing mechanisms through which stressors may exacerbate pain perception without affecting the sensorial dimension. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Comparison of personality traits, attitude toward orthodontic treatment, and pain perception and experience before and after orthodontic treatment.

PubMed

Abu Alhaija, Elham S; Abu Nabaa, Mona A; Al Maaitah, Emad F; Al-Omairi, Mahmoud K

2015-05-01

To compare personality traits, attitude toward orthodontic treatment, and pain perception and experience before and after orthodontic treatment. One hundred subjects (50 male and 50 female) were included in this study. The mean (SD) age was 17.5 (2.05) years at T1 and 19.15 (2.32) years at T2. The instruments for data collection were questionnaires that included assessment of patients' personality traits, attitudes toward orthodontic treatment, and pain perception/experience. Subjects completed the questionnaires at two different times: before orthodontic treatment (T1) and after fixed orthodontic treatment (T2). Subjects were treated by fixed orthodontic appliances for an average (SD) period of 18.64 (0.35) months. Paired sample t-test and chi-square test were used to detect any differences. Significant changes in personality traits were detected after orthodontic treatment irrespective of gender. Neuroticism, openness, agreeableness, and conscientiousness scores were improved (P < .001). A positive attitude toward orthodontic treatment was reported at T1 (4.31 [±1.26]) and improved at T2 (3.98 [±1.16]) irrespective of gender (P < .05). The average (SD) expected pain score (T1) was 4.73 (1.88) and the average (SD) experienced pain score (T2) was 4.63 (1.58). Significant difference in the expected and experienced pain scores was not detected (P  =  .11). Personality traits and attitude toward orthodontic treatment improved after orthodontic treatment. Reported actual pain experience during orthodontic treatment was similar to that expected before treatment.

New Strategies to Develop Novel Pain Therapies: Addressing Thermoreceptors from Different Points of View

PubMed Central

Fernández-Carvajal, Asia; Fernández-Ballester, Gregorio; Devesa, Isabel; González-Ros, José Manuel; Ferrer-Montiel, Antonio

2011-01-01

One approach to develop successful pain therapies is the modulation of dysfunctional ion channels that contribute to the detection of thermal, mechanical and chemical painful stimuli. These ion channels, known as thermoTRPs, promote the sensitization and activation of primary sensory neurons known as nociceptors. Pharmacological blockade and genetic deletion of thermoTRP have validated these channels as therapeutic targets for pain intervention. Several thermoTRP modulators have progressed towards clinical development, although most failed because of the appearance of unpredicted side effects. Thus, there is yet a need to develop novel channel modulators with improved therapeutic index. Here, we review the current state-of-the art and illustrate new pharmacological paradigms based on TRPV1 that include: (i) the identification of activity-dependent modulators of this thermoTRP channel; (ii) the design of allosteric modulators that interfere with protein-protein interaction involved in the functional coupling of stimulus sensing and gate opening; and (iii) the development of compounds that abrogate the inflammation-mediated increase of receptor expression in the neuronal surface. These new sites of action represent novel strategies to modulate pathologically active TRPV1, while minimizing an effect on the TRPV1 subpopulation involved in physiological and protective roles, thus increasing their potential therapeutic use. PMID:24288041

The effects of physical training without equipment on pain perception and balance in the elderly: A randomized controlled trial

PubMed Central

Patti, Antonino; Bianco, Antonino; Karsten, Bettina; Montalto, Maria Alessandra; Battaglia, Giuseppe; Bellafiore, Marianna; Cassata, Daniela; Scoppa, Fabio; Paoli, Antonio; Iovane, Angelo; Messina, Giuseppe; Palma, Antonio

2017-01-01

BACKGROUND: Research supports a link between exercise and falls prevention in the older population. OBJECTIVES: Our aims were to evaluate pain perception and balance skills in a group of elderly subjects and to examine the consequences of a standardized equipment-free exercise program intervention on these variables. The study utilized a randomized controlled trial method. METHODS: 92 subjects were recruited from a rural Sicilian village (Resuttano, Sicily, Italy). Subjects were randomly split into two groups, an experimental group (EG; n = 49) and a control group (CG; n = 43). Qualified fitness instructors delivered the standardized physical exercise program for the EG whilst the CG did not receive this exercise intervention. The Berg Balance Scale and the Oswestry Disability Index were administered in both groups before (T0) and after the intervention (T1). RESULTS: At T1, the EG group significantly improvement in balance (p < 0.0001) and pain perception (p < 0.0001). No significant differences were found within the CG both in BBS and ODI, respectively. CONCLUSIONS: Our findings suggest that a 13-weeks standardized exercise equipment-free program is effective in improving balance and perception of pain in the elderly. This type of intervention can consequently provide a low cost strategy to counteract the rate of disability in elderly. PMID:28506013

Cognitive modulation of pain and predictive coding. Comment on “Facing the experience of pain: A neuropsychological perspective” by Fabbro and Crescentini

NASA Astrophysics Data System (ADS)

Pagnoni, Giuseppe; Porro, Carlo A.

2014-09-01

Pain is a phenomenologically complex experience whose sensory and psychological dimensions are deeply intertwined. In their perspective article, Fabbro and Crescentini [1] review the physiological and neural mechanisms underlying nociception and its cognitive modulation within the broader concept of suffering, which includes psychological pain [2] in its culturally mediated and existentially nuanced forms. The tight link between affective and cognitive processes, on the one hand, and pain, on the other, is illustrated by examining in turn the placebo effect, empathy for other people's afflictions, clinical depression, and the role that mindfulness-based practices may play in alleviating suffering.

Paradoxical Pain Perception in Posttraumatic Stress Disorder: The Unique Role of Anxiety and Dissociation.

PubMed

Defrin, Ruth; Schreiber, Shaul; Ginzburg, Karni

2015-10-01

Posttraumatic stress disorder (PTSD) and chronic pain often co-occur and exacerbate each other. Elucidating the mechanism of this co-occurrence therefore has clinical importance. Previously, patients with PTSD with chronic pain were found to demonstrate a unique paradoxical pain profile: hyperresponsiveness together with hyposensitivity to pain. Our aim was to examine whether 2 seemingly paradoxical facets of PTSD (anxiety and dissociation) underlie this paradoxical profile. Patients with PTSD (n = 32) and healthy control individuals (n = 43) underwent psychophysical testing and completed questionnaires. Patients with PTSD had higher pain thresholds and higher pain ratings to suprathreshold stimuli than control individuals. Pain thresholds were positively associated with dissociation levels and negatively associated with anxiety sensitivity levels. Experimental pain ratings were positively associated with anxiety sensitivity and negatively related to dissociation levels. Chronic pain intensity was associated with anxiety, anxiety sensitivity, and pain catastrophizing. It appears that reduced conscious attention toward incoming stimuli, resulting from dissociation, causes delayed response in pain threshold measurement, whereas biases toward threatening stimuli and decreased inhibition, possibly caused by increased anxiety, are responsible for the intensification of experimental and chronic pain. The paradoxical facets of PTSD and their particular influences over pain perception seem to reinforce the coexistence of PTSD and chronic pain, and should be considered when treating traumatized individuals. This article provides new information regarding the underlying mechanism of the coexistence of PTSD and chronic pain. This knowledge could help to provide better management of PTSD and chronic pain among individuals in the aftermath of trauma. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Pain Perception in Phacoemulsification with Topical Anesthesia and Evaluation of Factors Related with Pain

PubMed Central

Dadacı, Zeynep; Borazan, Mehmet; Öncel Acır, Nurşen

2016-01-01

Objectives: Evaluation of pain during and after phacoemulsification with topical anesthesia in patients with senile cataract and investigation of factors related with pain. Materials and Methods: Ninety-two adult patients scheduled for routine clear corneal phacoemulsification with topical anesthesia who had no previous cataract surgery in their fellow eyes were included in the study. Verbal pain scale and visual analog scale were used to measure pain intensity. Demographic characteristics, concomitant systemic diseases, drug consumption, need of additional anesthesia during surgery, surgical complications, duration of surgery and surgeon comfort were also evaluated for each patient. Results: Seventy-two patients (78.3%) reported pain during surgery and 68 patients (73.9%) reported pain in the period after the surgery. When the intensity of pain during the surgery was evaluated, the percentage of patients reporting mild, moderate and intense pain was 35.9%, 25.0% and 17.4%, respectively. The average verbal pain score during the surgery was 1.4±1.0 (0-3). Reported pain level was not associated with age or gender (p>0.05). Diabetic patients and patients who consumed nonsteroidal anti-inflammatory drugs in the morning before operation reported less pain during and after the surgery (p<0.05). There were no complications except posterior capsule rupture in one patient. Duration of surgery was longer in patients who reported pain during surgery (p<0.05). There was no significant difference between pain reported during surgery and surgeon comfort (p>0.05). Conclusion: Patients frequently experience pain during phacoemulsification with topical anesthesia. Although pain perception does not affect surgical success, preoperative administration of analgesics in suitable patients or giving additional anesthesia to patients reporting severe pain during surgery may increase patient comfort. PMID:28058148

Effect of ambient temperature on human pain and temperature perception.

PubMed

Strigo, I A; Carli, F; Bushnell, M C

2000-03-01

Animal studies show reduced nociceptive responses to noxious heat stimuli and increases in endogenous beta-endorphin levels in cold environments, suggesting that human pain perception may be dependent on ambient temperature. However, studies of changes in local skin temperature on human pain perception have yielded variable results. This study examines the effect of both warm and cool ambient temperature on the perception of noxious and innocuous mechanical and thermal stimuli. Ten subjects (7 men and 3 women, aged 20-23 yr) used visual analog scales to rate the stimulus intensity, pain intensity, and unpleasantness of thermal (0-50 degrees C) and mechanical (1.2-28.9 g) stimuli applied on the volar forearm with a 1-cm2 contact thermode and von Frey filaments, respectively. Mean skin temperatures were measured throughout the experiment by infrared pyrometer. Each subject was tested in ambient temperatures of 15 degrees C (cool), 25 degrees C (neutral), and 35 degrees C (warm) on separate days, after a 30-min acclimation to the environment. Studies began in the morning after an 8-h fast. Mean skin temperature was altered by ambient temperature (cool room: 30.1 degrees C; neutral room: 33.4 degrees C; warm room: 34.5 degrees C; P < 0.0001). Ambient temperature affected both heat (44-50 degrees C) and cold (25-0 degrees C) perception (P < 0.01). Stimulus intensity ratings tended to be lower in the cool than in the neutral environment (P < 0.07) but were not different between the neutral and warm environments. Unpleasantness ratings revealed that cold stimuli were more unpleasant than hot stimuli in the cool room and that noxious heat stimuli were more unpleasant in a warm environment. Environmental temperature did not alter ratings of warm (37 and 40 degrees C) or mechanical stimuli. These results indicate that, in humans, a decrease in skin temperature following exposure to cool environments reduces thermal pain. Suppression of Adelta primary afferent cold fiber activity has been shown to increase cold pain produced by skin cooling. Our current findings may represent the reverse phenomenon, i.e., a reduction in thermal nociceptive transmission by the activation of Adelta cutaneous cold fibers.

Young people's experiences of persistent musculoskeletal pain, needs, gaps and perceptions about the role of digital technologies to support their co-care: a qualitative study.

PubMed

Slater, Helen; Jordan, Joanne E; Chua, Jason; Schütze, Robert; Wark, John D; Briggs, Andrew M

2016-12-09

To investigate young people's experiences of persistent musculoskeletal pain, including care needs and current service gaps as well as perceptions about the role of digital technologies to support their co-care. A qualitative study employing two independent data collection modes: in-depth individual semistructured interviews and focus groups. Community settings throughout Australia. Participants were included if they had experienced persistent musculoskeletal pain of >3-month duration with an average of ≥3 on the visual analogue scale over the preceding 3 months, including non-specific conditions (eg, low back pain) and specific conditions (eg, juvenile idiopathic arthritis and other systemic arthritides), with/without pre-existing or current diagnosed mental health conditions. 23 young people (87.0% women; mean (SD) age: 20.8 (2.4) years) from across 6 Australian jurisdictions participated. Almost two-thirds of participants with persistent musculoskeletal pain reported comorbid mental health conditions. Inductive and deductive approaches to analyse and derive key themes from verbatim transcripts. Participants described their daily experiences of living with persistent musculoskeletal pain, their fears and the challenges imposed by the invisibility of pain, and the two-way relationship between their pain and mental well-being. A lack of relevant and accessible information and resources tailored to young people's unique needs, integrated and youth-relevant healthcare services and adequately skilled healthcare practitioners were identified as key care gaps. Participants strongly advocated for the use of digital technologies to improve access to age-appropriate resources and support for co-care. Young people living with persistent musculoskeletal pain described the absence of age-appropriate pain services and clearly articulated their perceptions on the role of, and opportunities provided by, digital technologies to connect with and support improved pain healthcare. Innovative and digitally-enabled models of pain care are likely to be helpful for this group. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Does anodal transcranial direct current stimulation modulate sensory perception and pain? A meta-analysis study.

PubMed

Vaseghi, B; Zoghi, M; Jaberzadeh, S

2014-09-01

The primary aim of this systematic review was to evaluate the effects of anodal transcranial direct current stimulation (a-tDCS) on sensory (STh) and pain thresholds (PTh) in healthy individuals and pain levels (PL) in patients with chronic pain. Electronic databases were searched for a-tDCS studies. Methodological quality was examined using the PEDro and Downs and Black (D&B) assessment tools. a-tDCS of the primary motor cortex (M1) increases both STh (P<0.005, with the effect size of 22.19%) and PTh (P<0.001, effect size of 19.28%). In addition, STh was increased by a-tDCS of the primary sensory cortex (S1) (P<0.05 with an effect size of 4.34). Likewise, PL decreased significantly in the patient group following application of a-tDCS to both the M1 and dorsolateral prefrontal cortex (DLPFC). The average decrease in visual analogue score was 14.9% and 19.3% after applying a-tDCS on the M1 and DLPFC. Moreover, meta-analysis showed that in all subgroups (except a-tDCS of S1) active a-tDCS and sham stimulation produced significant differences. This review provides evidence for the effectiveness of a-tDCS in increasing STh/PTh in healthy group and decreasing PL in patients. However, due to small sample sizes in the included studies, our results should be interpreted cautiously. Given the level of blinding did not considered in inclusion criteria, the result of current study should be interpreted with caution. Site of stimulation should have a differential effect over pain relief. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Gender Differences Among Military Combatants: Does Social Support, Ostracism, and Pain Perception Influence Psychological Health?

PubMed

McGraw, Kate

2016-01-01

The literature on gender differences related to psychological health among in-theater service members who are deployed in a combatant role is limited. Much focuses on retrospective reports of service members who have returned from deployment. Potential key factors that contribute to gender differences in psychological health among combatants are found in literature across several topic areas, but integration of findings across disciplines is lacking. A growing body of literature on gender differences related to psychological health of postdeployment military populations suggests males and females respond differently to perceived levels of social support pre-and postdeployment. One study on service members who were deployed suggested no significant gender differences related to reported psychological health symptoms, but did appear to find significant gender differences related to reported perception of unit morale. In another related area, research explores how ostracism impacts physical and psychological health of individuals and organizations, and can result in perceptions of physical pain, although research on gender differences related to the impact of ostracism is scarce. Research has also begun to focus on sex differences in pain responses, and has identified multiple biopsychosocial, genetic, and hormonal factors that may contribute as potential underlying mechanisms. In this brief review, we focus on and begin to integrate relevant findings related to the psychological health of females in combat roles, gender differences in the impact of perception of social support on psychological health, the psychological and physical impact of ostracism on individuals and organizations, and the current literature on sex differences in pain perception. We conclude with a synthesis and discussion of research gaps identified through this review, implications for clinical practice, and potential future research directions. In conclusion, there appear to be gender differences related to the presence or absence of social support, the impact of ostracism, and the perception of pain. These differences may play a critical role in the psychological health of female combatants. More research on this topic is needed. Reprint & Copyright © 2016 Association of Military Surgeons of the U.S.

Implantation of hyaluronic acid hydrogel prevents the pain phenotype in a rat model of intervertebral disc injury

PubMed Central

Sakai, Daisuke; Dockery, Peter

2018-01-01

Painful intervertebral disc degeneration is mediated by inflammation that modulates glycosylation and induces hyperinnervation and sensory sensitization, which result in discogenic pain. Hyaluronic acid (HA) used as a therapeutic biomaterial can reduce inflammation and pain, but the effects of HA therapy on glycosylation and pain associated with disc degeneration have not been previously determined. We describe a novel rat model of pain induced by intervertebral disc injury, with validation of the pain phenotype by morphine treatment. Using this model, we assessed the efficacy of HA hydrogel for the alleviation of pain, demonstrating that it reduced nociceptive behavior, an effect associated with down-regulation of nociception markers and inhibition of hyperinnervation. Furthermore, HA hydrogel altered glycosylation and modulated key inflammatory and regulatory signaling pathways, resulting in attenuation of inflammation and regulation of matrix components. Our results suggest that HA hydrogel is a promising clinical candidate for the treatment of back pain caused by degenerated discs. PMID:29632893

Clinical presentation and manual therapy for upper quadrant musculoskeletal conditions

PubMed Central

Isabel de-la-Llave-Rincón, Ana; Puentedura, Emilio J; Fernández-de-las-Peñas, César

2011-01-01

In recent years, increased knowledge of the pathogenesis of upper quadrant pain syndromes has translated to better management strategies. Recent studies have demonstrated evidence of peripheral and central sensitization mechanisms in different local pain syndromes of the upper quadrant such as idiopathic neck pain, lateral epicondylalgia, whiplash-associated disorders, shoulder impingement, and carpal tunnel syndrome. Therefore, a treatment-based classification approach where subjects receive matched interventions has been developed and, it has been found that these patients experience better outcomes than those receiving non-matched interventions. There is evidence suggesting that the cervical and thoracic spine is involved in upper quadrant pain. Spinal manipulation has been found to be effective for patients with elbow pain, neck pain, or cervicobrachial pain. Additionally, it is known that spinal manipulative therapy exerts neurophysiological effects that can activate pain modulation mechanisms. This paper exposes some manual therapies for upper quadrant pain syndromes, based on a nociceptive pain rationale for modulating central nervous system including trigger point therapy, dry needling, mobilization or manipulation, and cognitive pain approaches. PMID:23115473

Effects of analgesics on olfactory function and the perception of intranasal trigeminal stimuli.

PubMed

Mizera, L; Gossrau, G; Hummel, T; Haehner, A

2017-01-01

There is some evidence suggesting that analgesics have an impact on human chemosensory function, especially opioids and cannabinoids are known to interfere with olfactory function. However, largely unknown is the effect of a long-term use of analgesics on the intranasal trigeminal system so far. Here, we investigated olfactory function and the perception of intranasal trigeminal stimuli in pain patients with long-term use of analgesics compared to age-matched healthy controls. For this purpose, a psychophysical approach was chosen to measure these sensory functions in 100 chronic pain patients and 95 controls. Olfactory testing was performed using the 'Sniffin' Sticks' test kit, which involves tests for odour threshold, odour discrimination and odour identification. Further, participants were asked to rate the intensity of trigeminal stimuli by using a visual analogue scale. We observed that the chronic use of pain medication was associated with significantly reduced perception of intranasal trigeminal stimuli and olfactory function compared to age-matched controls without intake of analgesics. Results indicate that non-opioid and opioid drugs, or a combination of both did not differ in their effects on chemosensory function. Further, after eliminating the effect of a co-existing depression and the use of co-analgesics, the negative influence of analgesics on olfactory function and trigeminal perception was still evident. The observed effect might be mediated due to interaction with opioid receptors in trigeminal ganglia and nuclei or due to trigeminal/olfactory interaction. As a practical consequence, patients should be made aware of a possible impairment of their olfactory and trigeminal function under long-term analgesic treatment. WHAT DOES THIS STUDY ADD?: We observed that the chronic use of pain medication was associated with significantly reduced olfactory function and perception of intranasal trigeminal stimuli compared to age-matched controls without intake of analgesics. Non-opioid and opioid drugs did not differ in their effects on chemosensory function. © 2016 European Pain Federation - EFIC®.

Colour expectations during object perception are associated with early and late modulations of electrophysiological activity.

PubMed

Stojanoski, Bobby Boge; Niemeier, Matthias

2015-10-01

It is well known that visual expectation and attention modulate object perception. Yet, the mechanisms underlying these top-down influences are not completely understood. Event-related potentials (ERPs) indicate late contributions of expectations to object processing around the P2 or N2. This is true independent of whether people expect objects (vs. no objects) or specific shapes, hence when expectations pertain to complex visual features. However, object perception can also benefit from expecting colour information, which can facilitate figure/ground segregation. Studies on attention to colour show attention-sensitive modulations of the P1, but are limited to simple transient detection paradigms. The aim of the current study was to examine whether expecting simple features (colour information) during challenging object perception tasks produce early or late ERP modulations. We told participants to expect an object defined by predominantly black or white lines that were embedded in random arrays of distractor lines and then asked them to report the object's shape. Performance was better when colour expectations were met. ERPs revealed early and late phases of modulation. An early modulation at the P1/N1 transition arguably reflected earlier stages of object processing. Later modulations, at the P3, could be consistent with decisional processes. These results provide novel insights into feature-specific contributions of visual expectations to object perception.

Postoperative pain management experiences among school-aged children: a qualitative study.

PubMed

Sng, Qian Wen; Taylor, Beverley; Liam, Joanne Lw; Klainin-Yobas, Piyanee; Wang, Wenru; He, Hong-Gu

2013-04-01

To explore postoperative pain management experiences among school-aged children. Ineffective postoperative pain management among children has been commonly reported. School-aged children are able to evaluate how their pain is managed and what their preferred strategies are. Most studies in pain management have adopted quantitative methods and have overlooked children's pain management experiences. This is a qualitative study using face-to-face interviews. Data were collected from 15 school-aged children admitted to a tertiary hospital in Singapore by in-depth interviews conducted between November 2010 and January 2011. Data were analysed by thematic analysis. Five themes were identified: children's self-directed actions to relieve their postoperative pain (e.g. using cognitive-behavioural methods of distraction and imagery, physical method of positioning, sleeping and drinking, seeking other people's help by informing parents and crying and using pain medications); children's perceptions of actions parents take for their postoperative pain relief (assessing pain, administering pain medications, using various cognitive-behavioural, physical methods and emotional support strategies, assisting in activities and alerting health professionals); children's perception of actions nurses take for their postoperative pain relief (administering medication, using cognitive-behavioural methods, emotional support strategies and helping with activities of daily living) and suggestions for parents (using distraction and presence) and nurses (administering medications, distraction and positioning) for their postoperative pain relief improvement. This study contributed to the existing knowledge about children's postoperative pain management based on their own experiences. Children, their parents and nurses used various strategies, including pain medication and non-pharmacological methods, especially distraction, for children's postoperative pain relief. This study provides evidence for health care professionals to consider using more pain relief strategies when caring for children postoperatively and provide guidance for children to practice these strategies. © 2013 Blackwell Publishing Ltd.

Novel Signs and Their Clinical Utility in Diagnosing Complex Regional Pain Syndrome (CRPS): A Prospective Observational Cohort Study.

PubMed

Kuttikat, Anoop; Shaikh, Maliha; Oomatia, Amin; Parker, Richard; Shenker, Nicholas

2017-06-01

Delays in diagnosis occur with complex regional pain syndrome (CRPS). We define and prospectively demonstrate that novel bedside tests measuring body perception disruption can identify patients with CRPS postfracture. The objectives of our study were to define and validate 4 bedside tests, to identify the prevalence of positive tests in patients with CRPS and other chronic pain conditions, and to assess the clinical utility (sensitivity, specificity, positive predictive value, negative predictive value) for identifying CRPS within a Fracture cohort. This was a single UK teaching hospital prospective cohort study with 313 recruits from pain-free volunteers and patients with chronic pain conditions.Four novel tests were Finger Perception (FP), Hand Laterality identification (HL), Astereognosis (AS), and Body Scheme (BS) report. Five questionnaires (Brief Pain Inventory, Upper Extremity Functional Index, Lower Extremity Functional Index, Neglect-like Symptom Questionnaire, Hospital Anxiety and Depression Score) assessed the multidimensional pain experience. FP and BS were the best performing tests. Prospective monitoring of fracture patients showed that out of 7 fracture patients (total n=47) who had both finger misperception and abnormal BS report at initial testing, 3 developed persistent pain with 1 having a formal diagnosis of CRPS. Novel signs are reliable, easy to perform, and present in chronic pain patients. FP and BS have significant clinical utility in predicting persistent pain in a fracture group thereby allowing targeted early intervention.

Differential pain modulation in patients with peripheral neuropathic pain and fibromyalgia.

PubMed

Gormsen, Lise; Bach, Flemming W; Rosenberg, Raben; Jensen, Troels S

2017-12-29

Background The definition of neuropathic pain has recently been changed by the International Association for the Study of Pain. This means that conditions such as fibromyalgia cannot, as sometimes discussed, be included in the neuropathic pain conditions. However, fibromyalgia and peripheral neuropathic pain share common clinical features such as spontaneous pain and hypersensitivity to external stimuli. Therefore, it is of interest to directly compare the conditions. Material and methods In this study we directly compared the pain modulation in neuropathic pain versus fibromyalgia by recording responses to a cold pressor test in 30 patients with peripheral neuropathic pain, 28 patients with fibromyalgia, and 26 pain-free age-and gender-matched healthy controls. Patients were asked to rate their spontaneous pain on a visual analog scale (VAS (0-100 mm) immediately before and immediately after the cold pressor test. Furthermore the duration (s) of extremity immersion in cold water was used as a measure of the pain tolerance threshold, and the perceived pain intensity at pain tolerance on the VAS was recorded on the extremity in the water after the cold pressor test. In addition, thermal (thermo tester) and mechanical stimuli (pressure algometer) were used to determine sensory detection, pain detection, and pain tolerance thresholds in different body parts. All sensory tests were done by the same examiner, in the same room, and with each subject in a supine position. The sequence of examinations was the following: (1) reaction time, (2) pressure thresholds, (3) thermal thresholds, and (4) cold pressor test. Reaction time was measured to ensure that psychomotoric inhibitions did not influence pain thresholds. Results Pain modulation induced by a cold pressor test reduced spontaneous pain by 40% on average in neuropathic pain patients, but increased spontaneous pain by 2.6% in fibromyalgia patients. This difference between fibromyalgia and neuropathic pain patients was significant (P < 0.002). Fibromyalgia patients withdrew their extremity from the cold water significantly earlier than neuropathic pain patients and healthy controls; however, they had a higher perceived pain intensity on the VAS than neuropathic pain patients and control subjects. Furthermore, neuropathic pain patients had a localized hypersensitivity to mechanical and thermal stimuli in the affected area of the body. In contrast, fibromyalgia patients displayed a general hypersensitivity to mechanical and thermal stimuli when the stimuli were rated by the VAS, and hypersensitivity to some of the sensory stimuli. Conclusions These findings are the first to suggest that a conditioning stimulus evoked by a cold pressor test reduced spontaneous ongoing pain in patients with peripheral neuropathic pain, but not in fibromyalgia patients when directly compared. The current study supports the notion that fibromyalgia and neuropathic pain are distinct pain conditions with separate sensory patterns and dysfunctions in pain-modulating networks. Fibromyalgia should therefore not, as sometimes discussed, be included in NP conditions. Implications On the basis of the findings, it is of interest to speculate on the underlying mechanisms. The results are consistent with the idea that peripheral neuropathic pain is primarily driven from damaged nerve endings in the periphery, while chronic fibromyalgia pain may be a central disorder with increased activity in pain-facilitating systems.

Extenuating Circumstances in Perceptions of Suicide: Disease Diagnosis (AIDS, Cancer), Pain Level, and Life Expectancy.

ERIC Educational Resources Information Center

Martin, Stephen K.; Range, Lillian M.

1991-01-01

Examined whether illness type, pain level, and life expectancy affected reactions of undergraduates (n=160) toward a terminal illness suicide with Acquired Immune Deficiency Syndrome (AIDS) or cancer. AIDS patients were more stigmatized than cancer patients; suicide was more tolerated if victim was suffering greater pain. (Author/ABL)

Enhanced pain perception prior to smoking cessation is associated with early relapse.

PubMed

Nakajima, Motohiro; al'Absi, Mustafa

2011-09-01

Accumulated evidence suggests that nicotine induces analgesia, and endogenous pain regulatory mechanisms may be altered by chronic smoking. The extent to which individual differences in pain perception are related to smokers' ability to abstain from smoking has not been directly examined. Seventy-one smokers who were interested in quitting completed a pre-cessation laboratory session which included the cold pressor test (CPT). Pain ratings were collected during and after CPT. Also, mood changes, cardiovascular measures, and salivary cortisol samples were evaluated prior to, during, and after CPT. Participants attended 4 weekly follow-up assessment sessions after their quit day. Cox regression analysis revealed that higher pain ratings during and after CPT predicted greater risk for smoking relapse. These results remained significant after affective and physiological responses to CPT were controlled, suggesting that pain ratings prior to smoking cessation are potentially useful in identifying smokers who are at greater risk of early smoking relapse and may reflect underlying putative risk for nicotine dependence and relapse. Copyright © 2011 Elsevier B.V. All rights reserved.

Transcranial Direct Current Stimulation (tDCS) Targeting Left Dorsolateral Prefrontal Cortex Modulates Task-Induced Acute Pain in Healthy Volunteers.

PubMed

Mariano, Timothy Y; Van't Wout, Mascha; Garnaat, Sarah L; Rasmussen, Steven A; Greenberg, Benjamin D

2016-04-01

Current chronic pain treatments target nociception rather than affective "suffering" and its associated functional and psychiatric comorbidities. The left dorsolateral prefrontal cortex (DLPFC) has been implicated in affective, cognitive, and attentional aspects of pain and is a primary target of neuromodulation for affective disorders. Transcranial direct current stimulation (tDCS) can non-invasively modulate cortical activity. The present study tests whether anodal tDCS targeting the left DLPFC will increase tolerability of acute painful stimuli vs cathodal tDCS. Forty tDCS-naive healthy volunteers received anodal and cathodal stimulation targeting the left DLPFC in two randomized and counterbalanced sessions. During stimulation, each participant performed cold pressor (CP) and breath holding (BH) tasks. We measured pain intensity with the Defense and Veterans Pain Rating Scale (DVPRS) before and after each task. Mixed ANOVA revealed no main effect of stimulation polarity for mean CP threshold, tolerance, or endurance, or mean BH time (allP > 0.27). However, DVPRS rise associated with CP was significantly smaller with anodal vs cathodal tDCS (P = 0.024). We further observed a significant tDCS polarity × stimulation order interaction (P = 0.042) on CP threshold, suggesting task sensitization. Although our results do not suggest that polarity of tDCS targeting the left DLPFC differentially modulates the tolerability of CP- and BH-related pain distress in healthy volunteers, there was a significant effect on DVPRS pain ratings. This contrasts with our previous findings that tDCS targeting the left dorsal anterior cingulate cortex showed a trend toward higher mean CP tolerance with cathodal vs anodal stimulation. The present results may suggest tDCS-related effects on nociception or DLPFC-mediated attention, or preferential modulation of the affective valence of pain as captured by the DVPRS. Sham-controlled clinical studies are needed. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

An imaging informatics-based system utilizing DICOM objects for treating pain in spinal cord injury patients utilizing proton beam radiotherapy

NASA Astrophysics Data System (ADS)

Verma, Sneha K.; Liu, Brent J.; Chun, Sophia; Gridley, Daila S.

2014-03-01

Many US combat personnel have sustained nervous tissue trauma during service, which often causes Neuropathic pain as a side effect and is difficult to manage. However in select patients, synapse lesioning can provide significant pain control. Our goal is to determine the effectiveness of using Proton Beam radiotherapy for treating spinal cord injury (SCI) related neuropathic pain as an alternative to invasive surgical lesioning. The project is a joint collaboration of USC, Spinal Cord Institute VA Healthcare System, Long Beach, and Loma Linda University. This is first system of its kind that supports integration and standardization of imaging informatics data in DICOM format; clinical evaluation forms outcomes data and treatment planning data from the Treatment planning station (TPS) utilized to administer the proton therapy in DICOM-RT format. It also supports evaluation of SCI subjects for recruitment into the clinical study, which includes the development, and integration of digital forms and tools for automatic evaluation and classification of SCI pain. Last year, we presented the concept for the patient recruitment module based on the principle of Bayesian decision theory. This year we are presenting the fully developed patient recruitment module and its integration to other modules. In addition, the DICOM module for integrating DICOM and DICOM-RT-ION data is also developed and integrated. This allows researchers to upload animal/patient study data into the system. The patient recruitment module has been tested using 25 retrospective patient data and DICOM data module is tested using 5 sets of animal data.

The association of greater dispositional optimism with less endogenous pain facilitation is indirectly transmitted through lower levels of pain catastrophizing

PubMed Central

Goodin, Burel R.; Glover, Toni L.; Sotolongo, Adriana; King, Christopher D.; Sibille, Kimberly T.; Herbert, Matthew S.; Cruz-Almeida, Yenisel; Sanden, Shelley H.; Staud, Roland; Redden, David T.; Bradley, Laurence A.; Fillingim, Roger B.

2012-01-01

Dispositional optimism has been shown to beneficially influence various experimental and clinical pain experiences. One possibility that may account for decreased pain sensitivity among individuals who report greater dispositional optimism is less use of maladaptive coping strategies like pain catastrophizing, a negative cognitive/affective response to pain. An association between dispositional optimism and conditioned pain modulation (CPM), a measure of endogenous pain inhibition, has previously been reported. However, it remains to be determined whether dispositional optimism is also associated with temporal summation (TS), a measure of endogenous pain facilitation. The current study examined whether pain catastrophizing mediated the association between dispositional optimism and TS among 140 older, community-dwelling adults with symptomatic knee osteoarthritis. Individuals completed measures of dispositional optimism and pain catastrophizing. TS was then assessed using a tailored heat pain stimulus on the forearm. Greater dispositional optimism was significantly related to lower levels of pain catastrophizing and TS. Bootstrapped confidence intervals revealed that less pain catastrophizing was a significant mediator of the relation between greater dispositional optimism and diminished TS. These findings support the primary role of personality characteristics such as dispositional optimism in the modulation of pain outcomes by abatement of endogenous pain facilitation and less use of catastrophizing. PMID:23218934

An Evaluation of the Effectiveness of a Vibrating Syringe Attachment in Decreasing Intraoral Injection Pain Perception

DTIC Science & Technology

2012-06-01

mucosa penetrations to periosteum by a 27-gauge short needle attached to a dental cartridge syringe . New needles were used for each injection, and the...of the American Dental Association, 134(2), 228-234. 7. Bonjar AHS. (2011) Syringe micro vibrator (SMV) a new device being introduced in dentistry...Lautenbacher S. (2004) Pathophysiology of Pain Perception. New York , New York : Kluwer and Plenum. 16 Flanagan T, Wahl MJ, Schmitt MM, Wahl JA. (2007) Size

Evaluating the advances and use of hypodermic needles in dentistry.

PubMed

Boynes, Sean G

2014-10-01

Different injection techniques and patient management methodologies have been proposed to decrease the fear patients may have concerning dental needles. Dental providers should have an understanding of the technological advances, changes in techniques, and patient perceptions associated with the hypodermic needle. This article provides an overview of the pain perception process associated with dental injections. It reviews the two main sensory nerve fibers associated with injection pain and discusses needle properties as well as complications and adverse occurrences.

Modulating the Delicate Glial-Neuronal Interactions in Neuropathic Pain: Promises and Potential Caveats

PubMed Central

Tiwari, Vinod; Guan, Yun; Raja, Srinivasa N.

2014-01-01

During neuropathic pain, glial cells (mainly astrocytes and microglia) become activated and initiate a series of signaling cascades that modulate pain processing at both spinal and supraspinal levels. It has been generally accepted that glial cell activation contributes to neuropathic pain because glia release proinflammatory cytokines, chemokines, and factors such as calcitonin gene-related peptide, substance P, and glutamate, which are known to facilitate pain signaling. However, recent research has shown that activation of glia also leads to some beneficial outcomes. Glia release anti-inflammatory factors that protect against neurotoxicity and restore normal pain. Accordingly, use of glial inhibitors might compromise the protective functions of glia in addition to suppressing their detrimental effects. With a better understanding of how different conditions affect glial cell activation, we may be able to promote the protective function of glia and pave the way for future development of novel, safe, and effective treatments of neuropathic pain. PMID:24820245

Mindful Yoga Pilot Study Shows Modulation of Abnormal Pain Processing in Fibromyalgia Patients.

PubMed

Carson, James W; Carson, Kimberly M; Jones, Kim D; Lancaster, Lindsay; Mist, Scott D

2016-01-01

Published findings from a randomized controlled trial have shown that Mindful Yoga training improves symptoms, functional deficits, and coping abilities in individuals with fibromyalgia and that these benefits are replicable and can be maintained 3 months post-treatment. The aim of this study was to collect pilot data in female fibromyalgia patients (n = 7) to determine if initial evidence indicates that Mindful Yoga also modulates the abnormal pain processing that characterizes fibromyalgia. Pre- and post-treatment data were obtained on quantitative sensory tests and measures of symptoms, functional deficits, and coping abilities. Separation test analyses indicated significant improvements in heat pain tolerance, pressure pain threshold, and heat pain after-sensations at post-treatment. Fibromyalgia symptoms and functional deficits also improved significantly, including physical tests of strength and balance, and pain coping strategies. These findings indicate that further investigation is warranted into the effect of Mindful Yoga on neurobiological pain processing.

The effect of hydromorphone therapy on psychophysical measurements of the descending inhibitory pain systems in patients with chronic radicular pain.

PubMed

Suzan, Erica; Treister, Roi; Pud, Dorit; Haddad, May; Eisenberg, Elon

2015-01-01

Conditioned pain modulation (CPM) and offset analgesia (OA) are considered to represent paradigms of descending inhibitory pain modulation in humans. This study tested the effects of hydromorphone therapy on descending inhibitory pain modulation, as measured by changes from baseline in the magnitudes of CPM and OA. Prospective evaluation. Institute of Pain Medicine, Rambam Health Care Campus. Patients with chronic radicular pain. Thirty patients received 4 weeks of oral hydromorphone treatment at an individually titrated dose (mean ± standard deviation dose of 11.6 ± 4.8 mg/day). CPM and OA were assessed before and after hydromorphone treatment. CPM was assessed by subtracting the response to a painful phasic heat stimulus administered simultaneously with a conditioning cold pain stimulus, from the response to the same heat stimulus administered alone. The OA paradigm consisted of a three-temperature stimuli train (T1 = 49°C [5 seconds], T2 = 50°C [5 seconds], and T3 = 49°C [20 seconds]). The magnitude of OA was quantified by subtracting minimal pain scores obtained during T3 from the maximal pain scores obtained during T2. CPM scores changed from a baseline of 17.7 ± 20.6 to 21 ± 20.4 following treatment, and OA scores changed from 7.8 ± 20.5 to 9.7 ± 14.6. Wilcoxon signed rank test indicated that these changes were not significant (CPM: P = 0.22; OA: P = 0.44). McNemar test revealed that the percentage of patients who exhibited a change in the direction of CPM or OA in response to hydromorphone treatment was not significant (CPM: P = 0.37; OA: P = 0.48). These results suggest that the descending inhibitory pain modulation, as manifested in humans by CPM and OA, is unlikely to be mediated by hydromorphone therapy. Wiley Periodicals, Inc.

Flexible Magnets Are Not Effective in Decreasing Pain Perception and Recovery Time After Muscle Microinjury

PubMed Central

Borsa, Paul A.; Liggett, Charles L.

1998-01-01

Objective: To assess the therapeutic effects of flexible magnets on pain perception, intramuscular swelling, range of motion, and muscular strength in individuals with a muscle microinjury. Design and Setting: This experiment was a single-blind, placebo study using a repeated-measures design. Subjects performed an intense exercise protocol to induce a muscle microinjury. After pretreatment measurements were recorded, subjects were randomly assigned to an experimental (magnet), placebo (imitation magnet), or control (no magnet) group. Posttreatment measurements were repeated at 24, 48, and 72 hours. Subjects: Forty-five healthy subjects participated in the study. Measurements: Subjects were measured repeatedly for pain perception, upper arm girth, range of motion, and static force production. Four separate univariate analyses of variances were used to reveal statistically significant mean (±SD) differences between variables over time. Interaction effects were analyzed using Scheffe post hoc analysis. Results: Analysis of variance revealed no statistically significant (P > .05) mean differences between conditions for any dependent pretreatment and posttreatment measurements. No significant interaction effects were demonstrated between conditions and times. Conclusions: No significant therapeutic effects on pain control and muscular dysfunction were observed in subjects wearing flexible magnets. ImagesFig 2.Fig 3. PMID:16558503

Abnormal pain perception in patients with Multiple System Atrophy.

PubMed

Ory-Magne, F; Pellaprat, J; Harroch, E; Galitzsky, M; Rousseau, V; Pavy-Le Traon, A; Rascol, O; Gerdelat, A; Brefel-Courbon, C

2018-03-01

Patients with Parkinson's disease or Multiple System Atrophy frequently experience painful sensations. The few studies investigating pain mechanisms in Multiple System Atrophy patients have reported contradictory results. In our study, we compared pain thresholds in Multiple System Atrophy and Parkinson's disease patients and healthy controls and evaluated the effect of l-DOPA on pain thresholds. We assessed subjective and objective pain thresholds (using a thermotest and RIII reflex), and pain tolerance in OFF and ON conditions, clinical pain, motor and psychological evaluation. Pain was reported in 78.6% of Multiple System Atrophy patients and in 37.5% of Parkinson's disease patients. In the OFF condition, subjective and objective pain thresholds were significantly lower in Multiple System Atrophy patients than in healthy controls (43.8 °C ± 1.3 vs 45.7 °C ± 0.8; p = 0.0005 and 7.4 mA ± 3.8 vs 13.7 mA ± 2.8; p = 0.002, respectively). They were also significantly reduced in Multiple System Atrophy compared to Parkinson's disease patients. No significant difference was found in pain tolerance for the 3 groups and in the effect of l-DOPA on pain thresholds in Multiple System Atrophy and Parkinson's disease patients. In the ON condition, pain tolerance tended to be reduced in Multiple System Atrophy versus Parkinson's disease patients (p = 0.05). Multiple System Atrophy patients had an increase in pain perception compared to Parkinson's disease patients and healthy controls. The l-DOPA effect was similar for pain thresholds in Multiple System Atrophy and Parkinson's disease patients, but tended to worsen pain tolerance in Multiple System Atrophy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Central Pain Processing in Early-Stage Parkinson's Disease: A Laser Pain fMRI Study

PubMed Central

Petschow, Christine; Scheef, Lukas; Paus, Sebastian; Zimmermann, Nadine; Schild, Hans H.; Klockgether, Thomas; Boecker, Henning

2016-01-01

Background & Objective Pain is a common non-motor symptom in Parkinson’s disease. As dopaminergic dysfunction is suggested to affect intrinsic nociceptive processing, this study was designed to characterize laser-induced pain processing in early-stage Parkinson’s disease patients in the dopaminergic OFF state, using a multimodal experimental approach at behavioral, autonomic, imaging levels. Methods 13 right-handed early-stage Parkinson’s disease patients without cognitive or sensory impairment were investigated OFF medication, along with 13 age-matched healthy control subjects. Measurements included warmth perception thresholds, heat pain thresholds, and central pain processing with event-related functional magnetic resonance imaging (erfMRI) during laser-induced pain stimulation at lower (E = 440 mJ) and higher (E = 640 mJ) target energies. Additionally, electrodermal activity was characterized during delivery of 60 randomized pain stimuli ranging from 440 mJ to 640 mJ, along with evaluation of subjective pain ratings on a visual analogue scale. Results No significant differences in warmth perception thresholds, heat pain thresholds, electrodermal activity and subjective pain ratings were found between Parkinson’s disease patients and controls, and erfMRI revealed a generally comparable activation pattern induced by laser-pain stimuli in brain areas belonging to the central pain matrix. However, relatively reduced deactivation was found in Parkinson’s disease patients in posterior regions of the default mode network, notably the precuneus and the posterior cingulate cortex. Conclusion Our data during pain processing extend previous findings suggesting default mode network dysfunction in Parkinson’s disease. On the other hand, they argue against a genuine pain-specific processing abnormality in early-stage Parkinson’s disease. Future studies are now required using similar multimodal experimental designs to examine pain processing in more advanced stages of Parkinson’s disease. PMID:27776130

Short-Term Sleep Disturbance-Induced Stress Does not Affect Basal Pain Perception, but Does Delay Postsurgical Pain Recovery.

PubMed

Wang, Po-Kai; Cao, Jing; Wang, Hongzhen; Liang, Lingli; Zhang, Jun; Lutz, Brianna Marie; Shieh, Kun-Ruey; Bekker, Alex; Tao, Yuan-Xiang

2015-11-01

Chronic sleep disturbance-induced stress is known to increase basal pain sensitivity. However, most surgical patients frequently report short-term sleep disturbance/deprivation during the pre- and postoperation periods and have normal pain perception presurgery. Whether this short-term sleep disturbance affects postsurgical pain is elusive. Here, we report that pre- or postexposure to rapid eye movement sleep disturbance (REMSD) for 6 hours daily for 3 consecutive days did not alter basal responses to mechanical, heat, and cold stimuli, but did delay recovery in incision-induced reductions in paw withdrawal threshold to mechanical stimulation and paw withdrawal latencies to heat and cold stimuli on the ipsilateral side of male or female rats. This short-term REMSD led to stress shown by an increase in swim immobility time, a decrease in sucrose consumption, and an increase in the level of corticosterone in serum. Blocking this stress via intrathecal RU38486 or bilateral adrenalectomy abolished REMSD-caused delay in recovery of incision-induced reductions in behavioral responses to mechanical, heat, and cold stimuli. Moreover, this short-term REMSD produced significant reductions in the levels of mu opioid receptor and kappa opioid receptor, but not Kv1.2, in the ipsilateral L4/5 spinal cord and dorsal root ganglia on day 9 after incision (but not after sham surgery). Our findings show that short-term sleep disturbance either pre- or postsurgery does not alter basal pain perception, but does exacerbate postsurgical pain hypersensitivity. The latter may be related to the reductions of mu and kappa opioid receptors in the spinal cord and dorsal root ganglia caused by REMSD plus incision. Prevention of short-term sleep disturbance may help recovery from postsurgical pain in patients. Copyright © 2015 American Pain Society. Published by Elsevier Inc. All rights reserved.

Pain Perception and Stabilometric Parameters in People With Chronic Low Back Pain After a Pilates Exercise Program

PubMed Central

Patti, Antonino; Bianco, Antonino; Paoli, Antonio; Messina, Giuseppe; Montalto, Maria Alessandra; Bellafiore, Marianna; Battaglia, Giuseppe; Iovane, Angelo; Palma, Antonio

2016-01-01

Abstract Various exercise interventions, such as Pilates exercises and traditional physical therapy methods, are employed to decrease low back pain (LBP). Nonspecific low back pain (NSLBP) is distinct from LBP, however, as the distribution of pain is restricted to the region between the costal margin and the inferior gluteal. The aim of our randomized controlled trial was to evaluate the effects of a program of Pilates exercises on pain perception and stabilometric parameters in patients with NSLBP. Thirty-eight participants were randomly allocated, using a 1:1 scheme, to either the experimental group (EG) or control group (CG). The EG completed a 14-week program of Pilates exercises, performed thrice per week under the supervision of an exercise specialist, while the CG was managed with a social program only. Measures of posturography and Oswestry Disability Index (ODI) for pain perception were obtained at baseline (T0) and after the 14 weeks of intervention (T1). Posturography measures improved for patients in the EG, with both eyes open and eyes closed (P < 0.05). There were no statistical differences in posturography in the CG. ODI decreased significantly in both groups over the 14 weeks of the study protocol: EG, T0, 13.7 ± 5.0 compared with T1, 6.5 ± 4.0 (P < 0.001); and CG, T0, 10.7 ± 7.8 compared with T1, 8.4 ± 7.8 (P < 0.01). A greater extent of reduction in pain was achieved in the EG. The Pilates exercise program yielded improvements in pain and posturography outcomes. Our study also confirms the applicability of posturography in evaluating postural instability in patients with NSLBP. Due to our relatively small study group, future studies would be necessary to confirm our findings. PMID:26765419

The pain of existing and religion from the perspective of Catholics 1

PubMed Central

Saltareli, Simone; Raminelli-da-Silva, Talita de Cássia; Castanho, Ana Carolina Ferreira; Falconi-Gomez, Rodrigo Ramon; Colhado, Orlando Carlos Gomes; Faleiros-Sousa, Fátima Aparecida Emm

2015-01-01

Abstract Objective: to characterize the understanding of leaders and members of the Catholic religion on pain of existing. Method: 80 Catholics participated in the study. Data collection was carried out using the Religious Content Assessment Tool. The content analysis was carried out and arithmetic mean and standard deviation were calculated. Results: the following categories emerged: length of affiliation, beginning of the religious practice and affiliation changes, responsibility for the actions and relationship with death, description of God, awareness of the existence of profound experiences, possibility of reward, increased faith in proximity to death, religion as an attempt to explain human limitations, relationship between religion and science and religion of the past and present in relation to science. On the instrument, the highest assigning items were: I believe that nature should be respected (9.96±0.19); I believe that all living beings deserve respect (9.70±0.67); make life worth living (9.70±0.78); my life is a transformation process (9.63±1.04) and I respect the diversity of people (9.56±0.91). Conclusion: it was observed associations between the participants' perceptions and religious constructs, highlighting the need to approach the religious phenomenon as part of the human being and potential resource for management and modulation of the pain of existing. PMID:26444171

Analgesic effect of clobazam in chronic low-back pain but not in experimentally induced pain.

PubMed

Schliessbach, J; Vuilleumier, P H; Siegenthaler, A; Bütikofer, L; Limacher, A; Juni, P; Zeilhofer, H U; Arendt-Nielsen, L; Curatolo, M

2017-09-01

Chronic pain is frequently associated with hypersensitivity of the nervous system, and drugs that increase central inhibition are therefore a potentially effective treatment. Benzodiazepines are potent modulators of GABAergic neurotransmission and are known to exert antihyperalgesic effects in rodents, but translation into patients are lacking. This study investigates the effect of the benzodiazepine clobazam in chronic low-back pain in humans. The aim of this study is to explore the effect of GABA modulation on chronic low-back pain and on quantitative sensory tests. In this double-blind cross-over study, 49 patients with chronic low-back pain received a single oral dose of clobazam 20 mg or active placebo tolterodine 1 mg. Pain intensity on the 0-10 numeric rating scale and quantitative sensory tests were assessed during 2 h after drug intake. Pain intensity in the supine position was significantly reduced by clobazam compared to active placebo (60 min: 2.9 vs. 3.5, p = 0.008; 90 min: 2.7 vs. 3.3, p = 0.024; 120 min: 2.4 vs. 3.1, p = 0.005). Pain intensity in the sitting position was not significantly different between groups. No effects on quantitative sensory tests were observed. This study suggests that clobazam has an analgesic effect in patients with chronic low-back pain. Muscle relaxation or sedation may have contributed to the effect. Development of substances devoid of these side effects would offer the potential to further investigate the antihyperalgesic action of GABAergic compounds. Modulation of GABAergic pain-inhibitory pathways may be a potential future therapeutic target. © 2017 European Pain Federation - EFIC®.

Characterization of peripheral and central sensitization after dorsal root ganglion intervention in patients with unilateral lumbosacral radicular pain: a prospective pilot study.

PubMed

Mehta, V; Snidvongs, S; Ghai, B; Langford, R; Wodehouse, T

2017-06-01

Quantitative sensory testing (QST) has been used to predict the outcome of epidural steroid injections in lumbosacral radicular pain and has the potential to be an important tool in the selection of appropriate treatment (such as epidural steroid injections vs surgery) for patients with chronic radicular pain. In addition, QST assists in identification of the pain pathways of peripheral and central sensitization in selected groups of patients. Twenty-three patients were given dorsal root ganglion (DRG) infiltration with local anaesthesia and steroid ('DRG block'), and those who demonstrated at least 50% pain relief were offered pulsed radiofrequency (PRF) to the DRG. Questionnaires and QST scores were measured before the DRG blocks and at 1 week and 3 months after their procedure. Those who received PRF also answered questionnaires and underwent QST measurements at 1 week and 3 months after their procedure. There was a significant increase in pressure pain threshold scores after DRG blocks. A reduced conditioned pain modulation response was seen before DRG, which increased after the procedure. Ten out of 23 patients underwent PRF to the DRG, and an increase in pressure pain threshold scores after PRF was observed. The conditioned pain modulation response was maintained in this group and increased after PRF. The study demonstrates that patients with unilateral radicular low back pain who receive dorsal root ganglion interventions show changes in pressure pain thresholds and conditioned pain modulation that are consistent with a 'normalization' of peripheral and central sensitization. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

The Cannabinoid System and Pain

PubMed Central

Woodhams, Stephen G.; Chapman, Victoria; Finn, David P.; Hohmann, Andrea G.; Neugebauer, Volker

2018-01-01

Chronic pain states are highly prevalent and yet poorly controlled by currently available analgesics, representing an enormous clinical, societal, and economic burden. Existing pain medications have significant limitations and adverse effects including tolerance, dependence, gastrointestinal dysfunction, cognitive impairment, and a narrow therapeutic window, making the search for novel analgesics ever more important. In this article, we review the role of an important endogenous pain control system, the endocannabinoid (EC) system, in the sensory, emotional, and cognitive aspects of pain. Herein, we briefly cover the discovery of the EC system and its role in pain processing pathways, before concentrating on three areas of current major interest in EC pain research; 1. Pharmacological enhancement of endocannabinoid activity (via blockade of EC metabolism or allosteric modulation of CB1 receptors); 2. The EC System and stress-induced modulation of pain; and 3. The EC system & medial prefrontal cortex (mPFC) dysfunction in pain states. Whilst we focus predominantly on the preclinical data, we also include extensive discussion of recent clinical failures of endocannabinoid-related therapies, the future potential of these approaches, and important directions for future research on the EC system and pain. PMID:28625720

Attitudes and concerns of Canadian animal health technologists toward postoperative pain management in dogs and cats.

PubMed

Dohoo, S E; Dohoo, I R

1998-08-01

Three hundred and twenty-two Canadian animal health technologists (AHTs) were surveyed to determine their attitudes toward postoperative pain management in dogs and cats following 6 surgical procedures, their concerns regarding the use of opioid analgesics, and their role within veterinary practices with respect to postoperative pain control. Two hundred and sixty-four (82%) returned the questionnaire. Pain perception was defined as the average of pain rankings for dogs and cats (on a scale of 1 to 10) following abdominal surgery, or the value for dogs or cats if the AHT worked with only 1 of the 2 species. Maximum concern about the risks associated with the postoperative use of morphine or oxymorphone was defined as the highest rating assigned to any of the 6 risks evaluated in either dogs or cats. Animal health technologists reported significantly higher pain perception scores than did veterinarians who completed a similar survey 2 years previously. Higher pain perception scores were associated with decreased satisfaction with the adequacy of analgesic therapy in their practice, higher pain control goals, and attendance at continuing education within the previous 12 months. The majority of AHTs (55%) agreed that one or more risks associated with the use of morphine or oxymorphone outweighed the benefits. The 3 issues that were perceived to pose the greatest risk were respiratory depression, bradycardia, and sedation and excitement, for dogs and cats, respectively. Most AHTs (68%) considered their knowledge related to the recognition and control of pain to be adequate, compared with 24% of veterinarians who responded to a similar previous survey. As for veterinarians, experience gained while in practice was ranked as the most important source of knowledge, while the technical program attended was ranked as least important. Over 88% of the AHTs provided nursing care during the postoperative period, monitored animals for side effects of postoperative analgesic therapy, informed veterinarians when animals were in pain, recommended analgesic therapy when they believed it was warranted, reported that animals received analgesics when they believed it was warranted, administered analgesics under the instruction of a veterinarian, and believed they were part of a team working to provide adequate postoperative pain control.

Factors influencing the postoperative use of analgesics in dogs and cats by Canadian veterinarians.

PubMed

Dohoo, S E; Dohoo, I R

1996-09-01

Four hundred and seventeen Canadian veterinarians were surveyed to determine their postoperative use of analgesics in dogs and cats following 6 categories of surgeries, and their opinion toward pain perception and perceived complications associated with the postoperative use of potent opioid analgesics. Three hundred and seventeen (76%) returned the questionnaire. An analgesic user was defined as a veterinarian who administers analgesics to at least 50% of dogs or 50% of cats following abdominal surgery, excluding ovariohysterectomy. The veterinarians responding exhibited a bimodal distribution of analgesic use, with 49.5% being defined as analgesic users. These veterinarians tended to use analgesics in 100% of animals following abdominal surgery. Veterinarians defined as analgesic nonusers rarely used postoperative analgesics following any abdominal surgery. Pain perception was defined as the average of pain rankings (on a scale of 1 to 10) following abdominal surgery, or the value for dogs or cats if the veterinarian worked with only 1 of the 2 species. Maximum concern about the risks associated with the postoperative use of potent opioid agonists was defined as the highest ranking assigned to any of the 7 risks evaluated in either dogs or cats. Logistic regression analysis identified the pain perception score and the maximum concern regarding the use of potent opioid agonists in the postoperative period as the 2 factors that distinguished analgesic users from analgesic nonusers. This model correctly classified 68% of veterinarians as analgesic users or nonusers. Linear regression analysis identified gender and the presence of an animal health technologist in the practice as the 2 factors that influenced pain perception by veterinarians. Linear regression analysis identified working with an animal health technologist, graduation within the past 10 years, and attendance at continuing education as factors that influenced maximum concern about the postoperative use of opioid agonists.

Talking About Sex When Sex Is Painful: Dyadic Sexual Communication Is Associated With Women's Pain, and Couples' Sexual and Psychological Outcomes in Provoked Vestibulodynia.

PubMed

Rancourt, Kate M; Rosen, Natalie O; Bergeron, Sophie; Nealis, Logan J

2016-11-01

Provoked vestibulodynia (PVD) is a recurrent vulvovaginal pain condition associated with psychological and sexual consequences for affected women and their partners, including lower quality of dyadic sexual communication compared to pain-free couples. Although greater sexual communication is associated with positive sexual and relational outcomes for both pain-free couples and couples experiencing painful sex, little is known about its role in women's pain and psychological outcomes, especially in a relational context. The present study examined associations between dyadic sexual communication and pain, sexual satisfaction, sexual functioning, and depressive symptoms in a sample of 107 couples in which the woman was diagnosed with PVD via a standardized gynecological assessment. Women completed a measure of pain intensity, and both members of the couple completed measures of their dyadic sexual communication, sexual satisfaction, sexual functioning, and depressive symptoms. Analyses were guided by the actor-partner interdependence model. Women and partners' own perceptions of greater dyadic sexual communication were associated with their own greater sexual satisfaction and sexual functioning, and lower depressive symptoms. Partners' perceptions of greater dyadic sexual communication were also associated with women's lower pain and greater sexual satisfaction. Results point to the importance of dyadic coping conceptualizations for both individual and interpersonal outcomes in PVD. Dyadic sexual communication may be a key treatment target for interventions aimed at improving the pain and psychological and sexual impairments of women with PVD and their partners.

Social hierarchy modulates neural responses of empathy for pain.

PubMed

Feng, Chunliang; Li, Zhihao; Feng, Xue; Wang, Lili; Tian, Tengxiang; Luo, Yue-Jia

2016-03-01

Recent evidence indicates that empathic responses to others' pain are modulated by various situational and individual factors. However, few studies have examined how empathy and underlying brain functions are modulated by social hierarchies, which permeate human society with an enormous impact on social behavior and cognition. In this study, social hierarchies were established based on incidental skill in a perceptual task in which all participants were mediumly ranked. Afterwards, participants were scanned with functional magnetic resonance imaging while watching inferior-status or superior-status targets receiving painful or non-painful stimulation. The results revealed that painful stimulation applied to inferior-status targets induced higher activations in the anterior insula (AI) and anterior medial cingulate cortex (aMCC), whereas these empathic brain activations were significantly attenuated in response to superior-status targets' pain. Further, this neural empathic bias to inferior-status targets was accompanied by stronger functional couplings of AI with brain regions important in emotional processing (i.e. thalamus) and cognitive control (i.e. middle frontal gyrus). Our findings indicate that emotional sharing with others' pain is shaped by relative positions in a social hierarchy such that underlying empathic neural responses are biased toward inferior-status compared with superior-status individuals. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Stability of conditioned pain modulation in two musculoskeletal pain models: investigating the influence of shoulder pain intensity and gender

PubMed Central

2013-01-01

Background Several chronic pain populations have demonstrated decreased conditioned pain modulation (CPM). However there is still a need to investigate the stability of CPM paradigms before the measure can be recommended for implementation. The purpose of the present study was to assess whether shoulder pain intensity and gender influence CPM stability within and between sessions. Methods This study examined two different musculoskeletal pain models, clinical shoulder pain and an experimental model of shoulder pain induced with eccentric exercise in healthy participants. Patients in the clinical cohort (N = 134) were tested before surgery and reassessed 3 months post-surgery. The healthy cohort (N = 190) was examined before inducing pain at the shoulder, and 48 and 96 hours later. Results Our results provide evidence that 1) stability of inhibition is not related to changes in pain intensity, and 2) there are sex differences for CPM stability within and between days. Conclusions Fluctuation of pain intensity did not significantly influence CPM stability. Overall, the more stable situations for CPM were females from the clinical cohort and males from the healthy cohort. PMID:23758907

[Pain in undernourished children: the mother's perception].

PubMed

Barbosa, Larissa Coelho; Martins, Mariana Cavalcante; Silva, Vanessa Aghata Guimarães da; Carvalho, Quitéria Clarice Magalhães

2005-01-01

This qualitative study aimed to identify how mothers perceive pain in their undernourished children. Semistructured interviews were realized at the Institute for the Prevention of Malnutrition and Exceptionality--IPREDE (Fortaleza-Ceará-Brazil). Participants were mothers who accompanied their undernourished children. Data analysis revealed the following categories: Coming to the Institution; Pain description and How to take care of the pain. Society needs to take actions, in respect of citizens' rights and culture, with a view to reverting this picture of pain in undernourished children.

Two Different Epidural Analgesic Combinations: Morphine vs. Fentanyl/Bupivacaine or Fentanyl/Ropivacaine and Their Post Operative Effects

DTIC Science & Technology

2001-10-01

Association for the Study of Pain defines pain as, "the sensory and emotional experiences associated with actual or potential tissue damage," (Taber, 1989...accentuating the pain response (Taber, 1989). In addition to the patients’ perception and experience of pain, the healthcare providers’ beliefs, biases...provide patients with quick recovery and pain-free postoperative experiences is a priority. The goal of this study was to compare the effectiveness

A Pilot Study of the Correlation between the Numeric Rating Scale used to Evaluate "Geop" and Questionnaires on Pain Perception.

PubMed

Koo, Bon Sung; Jung, Myung Jin; Lee, Joon Ho; Jin, Hee Cheol; Lee, Jeong Seok; Kim, Yong Ik

2015-01-01

The word "geop" is a unique Korean term commonly used to describe fright, fear and anxiety, and similar concepts. The purpose of this pilot study is to examine the correlation between the Numeric Rating Scale (NRS) score of geop and three different questionnaires on pain perception. Patients aged 20 to 70 years who visited our outpatient pain clinics were evaluated. They were requested to rate the NRS score (range: 0-100) if they felt geop. Next, they completed questionnaires on pain perception, in this case the Korean version of the Pain Sensitivity Questionnaire (PSQ), the Pain Catastrophizing Scale (PCS), and the Pain Anxiety Symptoms Scale (PASS). The correlations among each variable were evaluated by statistical analyses. There was no statistically significant correlation between the NRS score of geop and the PSQ score (r = 0.075, P = 0.5605). The NRS score of geop showed a significant correlation with the PCS total score (r = 0.346, P = 0.0063). Among the sub-scales, Rumination (r = 0.338, P = 0.0077) and Magnification (r = 0.343, P = 0.0069) were correlated with the NRS score of geop. In addition, the NRS score of geop showed a significant correlation with the PASS total score (r = 0.475, P = 0.0001). The cognitive (r = 0.473, P = 0.0002) and fear factors (r = 0.349, P = 0.0063) also showed significant correlations with the NRS score of geop. This study marks the first attempt to introduce the concept of "geop." The NRS score of geop showed a moderate positive correlation with the total PCS and PASS score. However, further investigations are required before the "geop" concept can be used practically in clinical fields.

Ionotropic glutamate receptors contribute to pain transmission and chronic pain.

PubMed

Zhuo, Min

2017-01-01

Investigation of the synaptic mechanisms for sensory transmission and modulation provide us with critical information about the transmission of painful sensation as well as the basic mechanisms of chronic pain. Recent studies consistently demonstrate that glutamatergic synapses not only play an important role in sensory transmission, including pain and itch transmission, but also contribute to nociceptive sensitization at different levels of the brain. Different subtypes of glutamate receptors play selective roles in synaptic transmission and long-term potentiation (LTP), as well as synaptic modulation. Understanding the contribution of each subtype of glutamate receptors, and related downstream signaling pathways may provide a new opportunity to design better medicine for the treatment of different forms of chronic pain. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'. Copyright © 2016 Elsevier Ltd. All rights reserved.

Targeting nociceptive transient receptor potential channels to treat chronic pain: current state of the field.

PubMed

Moran, Magdalene M; Szallasi, Arpad

2018-06-01

Control of chronic pain is frequently inadequate and/or associated with intolerable adverse effects, prompting a frantic search for new therapeutics and new therapeutic targets. Nearly two decades of preclinical and clinical research supports the involvement of transient receptor potential (TRP) channels in temperature perception, nociception and sensitization. Although there has been considerable excitement around the therapeutic potential of this channel family since the cloning and identification of TRPV1 cation channels as the capsaicin receptor more than 20 years ago, only modulators of a few channels have been tested clinically. TRPV1 channel antagonists have suffered from side effects related to the channel's role in temperature sensation; however, high dose formulations of capsaicin have reached the market and shown therapeutic utility. A number of potent, small molecule antagonists of TRPA1 channels have recently advanced into clinical trials for the treatment of inflammatory and neuropathic pain, and TRPM8 antagonists are following closely behind for cold allodynia. TRPV3, TRPV4, TRPM2 and TRPM3 channels have also been of significant interest. This review discusses the preclinical promise and status of novel analgesic agents that target TRP channels and the challenges that these compounds may face in development and clinical practice. This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc. © 2017 The British Pharmacological Society.

The effects of elevated pain inhibition on endurance exercise performance.

PubMed

Flood, Andrew; Waddington, Gordon; Keegan, Richard J; Thompson, Kevin G; Cathcart, Stuart

2017-01-01

The ergogenic effects of analgesic substances suggest that pain perception is an important regulator of work-rate during fatiguing exercise. Recent research has shown that endogenous inhibitory responses, which act to attenuate nociceptive input and reduce perceived pain, can be increased following transcranial direct current stimulation of the hand motor cortex. Using high-definition transcranial direct current stimulation (HD-tDCS; 2 mA, 20 min), the current study aimed to examine the effects of elevated pain inhibitory capacity on endurance exercise performance. It was hypothesised that HD-tDCS would enhance the efficiency of the endogenous pain inhibitory response and improve endurance exercise performance. Twelve healthy males between 18 and 40 years of age ( M  = 24.42 ± 3.85) were recruited for participation. Endogenous pain inhibitory capacity and exercise performance were assessed before and after both active and sham (placebo) stimulation. The conditioned pain modulation protocol was used for the measurement of pain inhibition. Exercise performance assessment consisted of both maximal voluntary contraction (MVC) and submaximal muscular endurance performance trials using isometric contractions of the non-dominant leg extensors. Active HD-tDCS (pre-tDCS, -.32 ± 1.33 kg; post-tDCS, -1.23 ± 1.21 kg) significantly increased pain inhibitory responses relative to the effects of sham HD-tDCS (pre-tDCS, -.91 ± .92 kg; post-tDCS, -.26 ± .92 kg; p  = .046). Irrespective of condition, peak MVC force and muscular endurance was reduced from pre- to post-stimulation. HD-tDCS did not significantly influence this reduction in maximal force (active: pre-tDCS, 264.89 ± 66.87 Nm; post-tDCS, 236.33 ± 66.51 Nm; sham: pre-tDCS, 249.25 ± 88.56 Nm; post-tDCS, 239.63 ± 67.53 Nm) or muscular endurance (active: pre-tDCS, 104.65 ± 42.36 s; post-tDCS, 93.07 ± 33.73 s; sham: pre-tDCS, 123.42 ± 72.48 s; post-tDCS, 100.27 ± 44.25 s). Despite increasing pain inhibitory capacity relative to sham stimulation, active HD-tDCS did not significantly elevate maximal force production or muscular endurance. These findings question the role of endogenous pain inhibitory networks in the regulation of exercise performance.

Therapeutic Massage During Chemotherapy and/or Biotherapy Infusions: Patient Perceptions of Pain, Fatigue, Nausea, Anxiety, and Satisfaction.

PubMed

Robison, Jeanene G; Smith, Cheryl L

2016-04-01

Patients with cancer commonly experience disease or treatment side effects, including pain, fatigue, nausea, and anxiety. An expanding body of literature supports the use of therapeutic massage (TM) as an adjunct to conventional therapies to manage these side effects. This article describes patients' perceptions of pain, fatigue, nausea, and anxiety and their overall satisfaction with TM provided concurrently with chemotherapy and/or biotherapy. In an academic outpatient comprehensive cancer center, consenting patients were asked to identify massage site preference (hands and/or feet). The licensed massage therapist delivered TM for 20 minutes to patients concurrently receiving chemotherapy and/or biotherapy. Patients rated their pain, fatigue, nausea, and anxiety pre- and post-TM using a Likert-type scale. Qualitative and quantitative data related to patients' perceived value of TM were obtained postintervention. Participants (N = 58) reported a statistically significant reduction in each of the following variables.

Specific conditions of distress in the dental situation.

PubMed

Hentschel, U; Allander, L; Winholt, A S

1977-01-01

The general feeling of distress in the dental situation has been studied in 60 female dental patients and correlated to the following variables: Experimentally evaluated sensitivity to pain, self-rating and the dentist's rating of sensitivity to pain, the pain-threshold value in the teeth, the need of local anesthesia, extraversion-introversion, neuroticism, and some percept-genetic psychological measures of adaptive behavior. The subjects have also answered a questionnaire for grading their distress in regard to different aspects of the treatment-situation, which were combined into eight groups using factor analysis and then correlated to the general distress. The variables having a significant relation to distress in the dental situation were: the dentist's rating of the patient's sensitivity, the need of anesthesia, four groups of treatment-components and two of the percept-genetic measures. There was also a certain relation to the pain threshold in the teeth.

Waning of "conditioned pain modulation": a novel expression of subtle pronociception in migraine.

PubMed

Nahman-Averbuch, Hadas; Granovsky, Yelena; Coghill, Robert C; Yarnitsky, David; Sprecher, Elliot; Weissman-Fogel, Irit

2013-01-01

To assess the decay of the conditioned pain modulation (CPM) response along repeated applications as a possible expression of subtle pronociception in migraine. One of the most explored mechanisms underlying the pain modulation system is "diffuse noxious inhibitory controls," which is measured psychophysically in the lab by the CPM paradigm. There are contradicting reports on CPM response in migraine, questioning whether migraineurs express pronociceptive pain modulation. Migraineurs (n = 26) and healthy controls (n = 35), all females, underwent 3 stimulation series, consisting of repeated (1) "test-stimulus" (Ts) alone that was given first followed by (2) parallel CPM application (CPM-parallel), and (3) sequential CPM application (CPM-sequential), in which the Ts is delivered during or following the conditioning-stimulus, respectively. In all series, the Ts repeated 4 times (0-3). In the CPM series, repetition "0" consisted of the Ts-alone that was followed by 3 repetitions of the Ts with a conditioning-stimulus application. Although there was no difference between migraineurs and controls for the first CPM response in each series, we found waning of CPM-parallel efficiency along the series for migraineurs (P = .005 for third vs first CPM), but not for controls. Further, greater CPM waning in the CPM-sequential series was correlated with less reported extent of pain reduction by episodic medication (r = 0.493, P = .028). Migraineurs have subtle deficits in endogenous pain modulation which requires a more challenging test protocol than the commonly used single CPM. Waning of CPM response seems to reveal this pronociceptive state. The clinical relevance of the CPM waning effect is highlighted by its association with clinical parameters of migraine. © 2013 American Headache Society.

Postoperative Pain and Analgesia: Is There a Genetic Basis to the Opioid Crisis?

PubMed

Elmallah, Randa K; Ramkumar, Prem N; Khlopas, Anton; Ramkumar, Rathika R; Chughtai, Morad; Sodhi, Nipun; Sultan, Assem A; Mont, Michael A

2018-06-01

Multiple factors have been implicated in determining why certain patients have increased postoperative pain, with the potential to develop chronic pain. The purpose of this study was to: 1) identify and describe genes that affect postoperative pain perception and control; 2) address modifiable risk factors that result in epigenetic altered responses to pain; and 3) characterize differences in pain sensitivity and thresholds between opioid-naïve and opioid-dependent patients. Three electronic databases were used to conduct the literature search: Pubmed, EBSCO host, and SCOPUS. A total of 372 abstracts were reviewed, of which 46 studies were deemed relevant and are included in this review. Specific gene alterations that were shown to affect postoperative pain control included single nucleotide polymorphisms in the mu, kappa, and delta opioid receptors, ion channel genes, cytotoxic T-cells, glutamate receptors and cytokine genes, among others. Alcoholism, obesity, and smoking were all linked with genetic polymorphisms that altered pain sensitivity. Opioid abuse was found to be associated with a poorer response to analgesics postoperatively, as well as a risk for prescription overdose. Although pain perception has multiple complex influences, the greatest variability seen in response to opioids among postoperative patients known to date can be traced to genetic differences in opioid metabolism. Further study is needed to determine the clinical significance of these genetic associations.

Thirst modulates a perception.

PubMed

Changizi, M A; Hall, W G

2001-01-01

Does thirst make you more likely to think you see water? Tales of thirsty desert travelers and oasis mirages are consistent with our intuitions that appetitive state can influence what we see in the world. Yet there has been surprisingly little scrutiny of this appetitive modulation of perception. We tested whether dehydrated subjects would be biased towards perceptions of transparency, a common property of water. We found that thirsty subjects have a greater tendency to perceive transparency in ambiguous stimuli, revealing an ecologically appropriate modulation of the visual system by a basic appetitive motive.

Multiple sites and actions of gabapentin-induced relief of ongoing experimental neuropathic pain.

PubMed

Bannister, Kirsty; Qu, Chaoling; Navratilova, Edita; Oyarzo, Janice; Xie, Jennifer Yanhua; King, Tamara; Dickenson, Anthony H; Porreca, Frank

2017-12-01

Gabapentin (GBP) is a first-line therapy for neuropathic pain, but its mechanisms and sites of action remain uncertain. We investigated GBP-induced modulation of neuropathic pain following spinal nerve ligation (SNL) in rats. Intravenous or intrathecal GBP reversed evoked mechanical hypersensitivity and produced conditioned place preference (CPP) and dopamine (DA) release in the nucleus accumbens (NAc) selectively in SNL rats. Spinal GBP also significantly inhibited dorsal horn wide-dynamic-range neuronal responses to a range of evoked stimuli in SNL rats. By contrast, GBP microinjected bilaterally into the rostral anterior cingulate cortex (rACC), produced CPP, and elicited NAc DA release selectively in SNL rats but did not reverse tactile allodynia and had marginal effects on wide-dynamic-range neuronal activity. Moreover, blockade of endogenous opioid signaling in the rACC prevented intravenous GBP-induced CPP and NAc DA release but failed to block its inhibition of tactile allodynia. Gabapentin, therefore, can potentially act to produce its pain relieving effects by (a) inhibition of injury-induced spinal neuronal excitability, evoked hypersensitivity, and ongoing pain and (b) selective supraspinal modulation of affective qualities of pain, without alteration of reflexive behaviors. Consistent with previous findings of pain relief from nonopioid analgesics, GBP requires engagement of rACC endogenous opioid circuits and downstream activation of mesolimbic reward circuits reflected in learned pain-motivated behaviors. These findings support the partial separation of sensory and affective dimensions of pain in this experimental model and suggest that modulation of affective-motivational qualities of pain may be the preferential mechanism of GBP's analgesic effects in patients.

Multiple sites and actions of gabapentin-induced relief of ongoing experimental neuropathic pain

PubMed Central

Bannister, Kirsty; Qu, Chaoling; Navratilova, Edita; Oyarzo, Janice; Xie, Jennifer Yanhua; King, Tamara; Dickenson, Anthony H.; Porreca, Frank

2017-01-01

Gabapentin is a first-line therapy for neuropathic pain but its mechanisms and sites of action remain uncertain. We investigated gabapentin-induced modulation of neuropathic pain following spinal nerve ligation (SNL) in rats. Intravenous or intrathecal gabapentin reversed evoked mechanical hypersensitivity, produced conditioned place preference (CPP) and dopamine release in the nucleus accumbens (NAc) selectively in SNL rats. Spinal gabapentin also significantly inhibited dorsal horn wide dynamic range (WDR) neuronal responses to a range of evoked stimuli in SNL rats. In contrast, gabapentin microinjected bilaterally into the rostral anterior cingulate cortex (rACC), produced CPP and elicited NAc dopamine release selectively in SNL rats but did not reverse tactile allodynia and had marginal effects on WDR neuronal activity. Moreover, blockade of endogenous opioid signaling in the rACC prevented intravenous gabapentin-induced CPP and NAc dopamine release but failed to block its inhibition of tactile allodynia. Gabapentin therefore can potentially act to produce its pain relieving effects by (a) inhibition of injury-induced spinal neuronal excitability, evoked hypersensitivity and ongoing pain and (b) selective supraspinal modulation of affective qualities of pain, without alteration of reflexive behaviors. Consistent with previous findings of pain relief from non-opioid analgesics, gabapentin requires engagement of rACC endogenous opioid circuits and downstream activation of mesolimbic reward circuits reflected in learned pain motivated behaviors. These findings support the partial separation of sensory and affective dimensions of pain in this experimental model and suggest that modulation of affective-motivational qualities of pain may be the preferential mechanism of gabapentin’s analgesic effects in patients. PMID:28832395

Deficiency in endogenous modulation of prolonged heat pain in patients with Irritable Bowel Syndrome and Temporomandibular Disorder

PubMed Central

King, Christopher D.; Wong, Fong; Currie, Tom; Mauderli, Andre P.; Fillingim, Roger B.; Riley, Joseph L.

2013-01-01

Females with Irritable Bowel Syndrome (IBS) and Temporomandibular Disorder (TMD) are characterized by enhanced sensitivity to experimental pain. One possible explanation for this observation is deficiencies in pain modulation systems like Diffuse Noxious Inhibitory Control (DNIC). In a few studies that used brief stimuli, chronic pain patients demonstrate reduced DNIC. The purpose of this study was to compare sensitivity to prolonged heat pain and the efficacy of DNIC in controls to IBS and TMD patients. Heat pain (experimental stimulus; 44.0-49.0°C), which was applied to left palm, was continuously rated during three 30-second trials across three separate testing sessions under the following conditions: without a conditioning stimulus; during concurrent immersion of the right foot in a 23.0°C (control); and during noxious cold immersion in a (DNIC; 8.0-16.0°C) water bath. Compared to controls, IBS and TMD patients reported increased sensitivity to heat pain and failed to demonstrate pain inhibition due to DNIC. Controls showed a significant reduction in pain during the DNIC session. These findings support the idea that chronic pain patients are not only more pain sensitive and demonstrate reduced pain inhibition by pain, possibly because of dysfunction of endogenous pain inhibition systems. PMID:19278784

Nociception at the diabetic foot, an uncharted territory

PubMed Central

Chantelau, Ernst A

2015-01-01

The diabetic foot is characterised by painless foot ulceration and/or arthropathy; it is a typical complication of painless diabetic neuropathy. Neuropathy depletes the foot skin of intraepidermal nerve fibre endings of the afferent A-delta and C-fibres, which are mostly nociceptors and excitable by noxious stimuli only. However, some of them are cold or warm receptors whose functions in diabetic neuropathy have frequently been reported. Hence, it is well established by quantitative sensory testing that thermal detection thresholds at the foot skin increase during the course of painless diabetic neuropathy. Pain perception (nociception), by contrast, has rarely been studied. Recent pilot studies of pinprick pain at plantar digital skinfolds showed that the perception threshold was always above the upper limit of measurement of 512 mN (equivalent to 51.2 g) at the diabetic foot. However, deep pressure pain perception threshold at musculus abductor hallucis was beyond 1400 kPa (equivalent to 14 kg; limit of measurement) only in every fifth case. These discrepancies of pain perception between forefoot and hindfoot, and between skin and muscle, demand further study. Measuring nociception at the feet in diabetes opens promising clinical perspectives. A critical nociception threshold may be quantified (probably corresponding to a critical number of intraepidermal nerve fibre endings), beyond which the individual risk of a diabetic foot rises appreciably. Staging of diabetic neuropathy according to nociception thresholds at the feet is highly desirable as guidance to an individualised injury prevention strategy. PMID:25897350

Feature-Based Attention in Early Vision for the Modulation of Figure–Ground Segregation

PubMed Central

Wagatsuma, Nobuhiko; Oki, Megumi; Sakai, Ko

2013-01-01

We investigated psychophysically whether feature-based attention modulates the perception of figure–ground (F–G) segregation and, based on the results, we investigated computationally the neural mechanisms underlying attention modulation. In the psychophysical experiments, the attention of participants was drawn to a specific motion direction and they were then asked to judge the side of figure in an ambiguous figure with surfaces consisting of distinct motion directions. The results of these experiments showed that the surface consisting of the attended direction of motion was more frequently observed as figure, with a degree comparable to that of spatial attention (Wagatsuma et al., 2008). These experiments also showed that perception was dependent on the distribution of feature contrast, specifically the motion direction differences. These results led us to hypothesize that feature-based attention functions in a framework similar to that of spatial attention. We proposed a V1–V2 model in which feature-based attention modulates the contrast of low-level feature in V1, and this modulation of contrast changes directly the surround modulation of border-ownership-selective cells in V2; thus, perception of F–G is biased. The model exhibited good agreement with human perception in the magnitude of attention modulation and its invariance among stimuli. These results indicate that early-level features that are modified by feature-based attention alter subsequent processing along afferent pathway, and that such modification could even change the perception of object. PMID:23515841

Feature-based attention in early vision for the modulation of figure-ground segregation.

PubMed

Wagatsuma, Nobuhiko; Oki, Megumi; Sakai, Ko

2013-01-01

We investigated psychophysically whether feature-based attention modulates the perception of figure-ground (F-G) segregation and, based on the results, we investigated computationally the neural mechanisms underlying attention modulation. In the psychophysical experiments, the attention of participants was drawn to a specific motion direction and they were then asked to judge the side of figure in an ambiguous figure with surfaces consisting of distinct motion directions. The results of these experiments showed that the surface consisting of the attended direction of motion was more frequently observed as figure, with a degree comparable to that of spatial attention (Wagatsuma et al., 2008). These experiments also showed that perception was dependent on the distribution of feature contrast, specifically the motion direction differences. These results led us to hypothesize that feature-based attention functions in a framework similar to that of spatial attention. We proposed a V1-V2 model in which feature-based attention modulates the contrast of low-level feature in V1, and this modulation of contrast changes directly the surround modulation of border-ownership-selective cells in V2; thus, perception of F-G is biased. The model exhibited good agreement with human perception in the magnitude of attention modulation and its invariance among stimuli. These results indicate that early-level features that are modified by feature-based attention alter subsequent processing along afferent pathway, and that such modification could even change the perception of object.

Transcranial Direct Current Stimulation (tDCS) Targeting Left Dorsolateral Prefrontal Cortex Modulates Task-Induced Acute Pain in Healthy Volunteers

PubMed Central

Mariano, Timothy Y.; Wout, Mascha van't; Garnaat, Sarah L.; Rasmussen, Steven A.; Greenberg, Benjamin D.

2016-01-01

Objective Current chronic pain treatments target nociception rather than affective “suffering” and its associated functional and psychiatric comorbidities. Left dorsolateral prefrontal cortex (DLPFC) has been implicated in affective, cognitive, and attentional aspects of pain and is a primary target of neuromodulation for affective disorders. Transcranial direct current stimulation (tDCS) can noninvasively modulate cortical activity. The present study tests if anodal tDCS targeting left DLPFC will increase tolerability of acute painful stimuli versus cathodal tDCS. Methods Forty tDCS-naive healthy volunteers received anodal and cathodal stimulation targeting left DLPFC in two randomized and counterbalanced sessions. During stimulation, each participant performed cold pressor (CP) and breath holding (BH) tasks. We measured pain intensity with the Defense and Veterans Pain Rating Scale (DVPRS) before and after each task. Results Mixed ANOVA revealed no main effect of stimulation polarity for mean CP threshold, tolerance, or endurance, or mean BH time (all p > 0.27). However, DVPRS rise associated with CP was significantly smaller with anodal versus cathodal tDCS (p = 0.024). We further observed a significant tDCS polarity × stimulation order interaction (p = 0.042) on CP threshold suggesting task sensitization. Conclusions Although our results do not suggest that polarity of tDCS targeting left DLPFC differentially modulates tolerability of CP- and BH-related pain distress in healthy volunteers, there was a significant effect on DVPRS pain ratings. This contrasts with our previous findings that tDCS targeting left dorsal anterior cingulate cortex showed a trend towards higher mean CP tolerance with cathodal versus anodal stimulation. The present results may suggest tDCS-related effects on nociception or DLPFC-mediated attention, or preferential modulation of the affective valence of pain as captured by DVPRS. Sham-controlled clinical studies are needed. PMID:26814276

Partner Loss in Monogamous Rodents: Modulation of Pain and Emotional Behavior in Male Prairie Voles.

PubMed

Osako, Yoji; Nobuhara, Reiko; Arai, Young-Chang P; Tanaka, Kenjiro; Young, Larry J; Nishihara, Makoto; Mitsui, Shinichi; Yuri, Kazunari

2018-01-01

Pain is modulated by psychosocial factors, and social stress-induced hyperalgesia is a common clinical symptom in pain disorders. To provide a new animal model for studying social modulation of pain, we examined pain behaviors in monogamous prairie voles experiencing partner loss. After cohabitation with novel females, males (n = 79) were divided into two groups on the basis of preference test scores. Half of the males of each group were separated from their partner (loss group), whereas the other half remained paired (paired group). Thus, males from both groups experienced social isolation. Open field tests, plantar tests, and formalin tests were then conducted on males to assess anxiety and pain-related behaviors. Loss males showing partner preferences (n = 20) displayed a significant increase in anxiety-related behavior in the open-field test (central area/total distance: 13.65% [1.58%] for paired versus 6.45% [0.87%] for loss; p < .001), a low threshold of thermal stimulus in the plantar test (withdrawal latencies: 9.69 [0.98] seconds for paired versus 6.15 [0.75] seconds for loss; p = .037), and exacerbated pain behaviors in the formalin test (total number of lifts: 40.33 [4.46] for paired versus 54.42 [1.91] for loss; p = .042) as compared with paired males (n = 20). Thermal thresholds in the plantar test significantly correlated with anxiety-related behavior in the open-field test (r = 0.64). No such differences were observed in the males that did not display partner preferences (r = 0.15). Results indicate that social bonds and their disruption, but not social housing without bonding followed by isolation, modulate pain and emotion in male prairie voles. The prairie vole is a useful model for exploring the neural mechanisms by which social relationships contribute to pain and nociceptive processing in humans.

Recurrent pain and discomfort in relation to fitness and physical activity among young school children.

PubMed

Sollerhed, Ann-Christin; Andersson, Ingemar; Ejlertsson, Göran

2013-01-01

As an increase in pain symptoms among children has been shown in the last decades, the aim of this study was to describe perceptions of recurrent pain, measured physical fitness and levels of reported physical activity (PA) in children, and to investigate if any associations between PA, fitness and recurrent pain could be identified. A school-based study comprised 206 Swedish children 8-12 years old, 114 boys, 92 girls. A questionnaire with questions about perceived pain, self-reported PA and lifestyle factors was used. Health-related fitness was assessed by 11 physical tests. A physical index was calculated from these tests as a z score. High physical index indicated high fitness and low physical index indicated low fitness. ANOVA test, chi-square test and logistic regression analysis were used to compare active and inactive children. The prevalence of one pain location (head, abdomen or back) was 26%, two 11% and three 4% (n=206). Female gender, living in single-parent families, low PA and low subjective health were associated with reported recurrent pain. Children reporting high levels of PA had high physical index and reported low prevalence of pain symptoms. The physical index and level of self-reported PA decreased gradually the more pain locations. Physically active children had higher fitness levels and reported less pain symptoms than inactive peers. Coping with pain is an integral part of PA, and active children learn to cope with unpleasant body sensations which together with high fitness may reduce the perception of pain.

An Insight Into Neurophysiology of Pulpal Pain: Facts and Hypotheses

PubMed Central

Gupta, Abhishek; N., Meena

2013-01-01

Pain and pain control are important to the dental profession because the general perception of the public is that dental treatment and pain go hand in hand. Successful dental treatment requires that the source of pain be detected. If the origin of pain is not found, inappropriate dental care and, ultimately, extraction may result. Pain experienced before, during, or after endodontic therapy is a serious concern to both patients and endodontists, and the variability of discomfort presents a challenge in terms of diagnostic methods, endodontic therapy, and endodontic knowledge. This review will help clinicians understand the basic neurophysiology of pulpal pain and other painful conditions of the dental pulp that are not well understood. PMID:24156000

An insight into neurophysiology of pulpal pain: facts and hypotheses.

PubMed

Jain, Niharika; Gupta, Abhishek; N, Meena

2013-10-01

Pain and pain control are important to the dental profession because the general perception of the public is that dental treatment and pain go hand in hand. Successful dental treatment requires that the source of pain be detected. If the origin of pain is not found, inappropriate dental care and, ultimately, extraction may result. Pain experienced before, during, or after endodontic therapy is a serious concern to both patients and endodontists, and the variability of discomfort presents a challenge in terms of diagnostic methods, endodontic therapy, and endodontic knowledge. This review will help clinicians understand the basic neurophysiology of pulpal pain and other painful conditions of the dental pulp that are not well understood.

Effect of pinching-evoked pain on jaw-stretch reflexes and exteroceptive suppression periods in healthy subjects.

PubMed

Biasiotta, A; Peddireddy, A; Wang, K; Romaniello, A; Frati, A; Svensson, P; Arendt-Nielsen, L

2007-10-01

To investigate the influence of conditioning cutaneous nociceptive inputs by a new "pinch" model on the jaw-stretch reflex and the exteroceptive suppression periods (ES1 and ES2) in jaw muscles. The jaw-stretch reflex was evoked with the use of a custom-made muscle stretcher and electrical stimuli were used to evoke an early and late exteroceptive suppression period (ES1 and ES2) in the jaw-closing muscles. Electromyographic (EMG) activity was recorded bilaterally from the masseter and temporalis muscles. These brainstem reflexes were recorded in 19 healthy men (28.8+/-1.1 years) during three different conditions: one painful clip applied to the earlobe; one painful clip applied to the nostril, and four painful clips applied simultaneously to the earlobe, nostril, eyebrow, and lower lip. Pain intensity induced by the application of the clips was scored continuously by the subjects on a 100mm visual analogue scale (VAS). The highest VAS pain scores were evoked by placement of four clips (79+/-0.5mm). There was no significant modulation of the jaw-stretch reflex (ANOVAs: P=0.929), the ES1 (P=0.298) or ES2 (P=0.082) in any of the three painful conditions. Intense and tonic cutaneous pain could be elicited by this new "pinch" pain model; however, there was no significant modulation on either excitatory or inhibitory brainstem reflex responses. The novel observation that high-intensity pinch stimuli applied to the craniofacial region fail to modulate two different brainstem reflexes is in contrast to other experimental pain studies documented facilitation of the jaw-stretch reflexes or inhibition of exteroceptive suppression periods. The clinical implication of the present findings is that only some craniofacial pain conditions could be expected to show perturbation of the brainstem reflex responses.

Deep brain stimulation of the ventral striatal area for poststroke pain syndrome: a magnetoencephalography study.

PubMed

Gopalakrishnan, Raghavan; Burgess, Richard C; Malone, Donald A; Lempka, Scott F; Gale, John T; Floden, Darlene P; Baker, Kenneth B; Machado, Andre G

2018-06-01

Poststroke pain syndrome (PSPS) is an often intractable disorder characterized by hemiparesis associated with unrelenting chronic pain. Although traditional analgesics have largely failed, integrative approaches targeting affective-cognitive spheres have started to show promise. Recently, we demonstrated that deep brain stimulation (DBS) of the ventral striatal area significantly improved the affective sphere of pain in patients with PSPS. In the present study, we examined whether electrophysiological correlates of pain anticipation were modulated by DBS that could serve as signatures of treatment effects. We recorded event-related fields (ERFs) of pain anticipation using magnetoencephalography (MEG) in 10 patients with PSPS preoperatively and postoperatively in DBS OFF and ON states. Simple visual cues evoked anticipation as patients awaited a painful (PS) or nonpainful stimulus (NPS) to the nonaffected or affected extremity. Preoperatively, ERFs showed no difference between PS and NPS anticipation to the affected extremity, possibly due to loss of salience in a network saturated by pain experience. DBS significantly modulated the early N1, consistent with improvements in affective networks involving restoration of salience and discrimination capacity. Additionally, DBS suppressed the posterior P2 (aberrant anticipatory anxiety) while enhancing the anterior N1 (cognitive and emotional regulation) in responders. DBS-induced changes in ERFs could potentially serve as signatures for clinical outcomes. NEW & NOTEWORTHY We examined the electrophysiological correlates of pain affect in poststroke pain patients who underwent deep brain stimulation (DBS) targeting the ventral striatal area under a randomized, controlled trial. DBS significantly modulated early event-related components, particularly N1 and P2, measured with magnetoencephalography during a pain anticipatory task, compared with baseline and the DBS-OFF condition, pointing to possible mechanisms of action. DBS-induced changes in event-related fields could potentially serve as biomarkers for clinical outcomes.

A geriatric assessment in general practice: prevalence, location, impact and doctor-patient perceptions of pain.

PubMed

Kruschinski, Carsten; Wiese, Birgitt; Dierks, Marie-Luise; Hummers-Pradier, Eva; Schneider, Nils; Junius-Walker, Ulrike

2016-01-28

To investigate what a geriatric assessment in general practice adds towards previous findings of prevalence, location, impact and the dyadic doctor-patient perception of pain in this age group. Cross-sectional study. Consecutive patients aged 70 and over underwent a comprehensive geriatric assessment in general practice that included a basic pain assessment (severity, sites and impact). Patients with pain and their doctors then independently rated its importance. Pain was correlated with further findings from the assessment, such as overall health, physical impairments, everyday function, falls, mood, health related lifestyle, social circumstances, using bivariate and multivariate statistics. Patient-doctor agreement on the importance of pain was calculated using kappa statistics. 219 out of 297 patients (73.7 %) reported pain at any location. Pain was generally located at multiple sites. It was most often present at the knee (33.9%), the lumbar spine (33.5%) as well as the hip (13.8%) and correlated with specific impairments such as restrictions of daily living (knee) or sleep problems (spine). Patients with pain and their physicians poorly agreed on the importance of the pain problem. A basic pain assessment can identify older patients with pain in general practice. It has resulted in a high prevalence exceeding that determined by encounters in consultations. It has been shown that a geriatric assessment provides an opportunity to address pain in a way that is adapted to older patients' needs - addressing all sites, its specific impact on life, and the patients' perceived importance of pain. Since there is little doctor-patient agreement, this seems a valuable strategy to optimize concrete treatment decisions and patient centered care. This study is registered in the German Clinical Trial Register ( DRKS00000792 ).

The Effect of Pain on Task Performance: A Review of the Literature.

DTIC Science & Technology

1992-07-01

Pharmacology. 11 (2), 123-127 (1989) 8. J. D. Benson, Application of manual handling task in the control of low back pain. In Trends in Ergonomics /Human...Factors IV. Proceedings of the Annual International Industrial Ergonomics and Safety Conference. Amsterdam: Elsevier Science Publishers (1987). 9. T...development of a motor performance method for the measurement of pain. Ergonomics . 32 (3), 307-316 (1989) 67. K. Sedlak, Low-back pain perception and