Video head impulse test: a review of the literature.

PubMed

Alhabib, Salman F; Saliba, Issam

2017-03-01

Video head impulse test (vHIT) is a new testing which able to identify the overt and covert saccades and study the gain of vestibulo-ocular reflex (VOR) of each semicircular canal. The aim of this study is to review the clinical use of vHIT in patients with vestibular disorders in different diseases. PubMed and Cochrane databases were searched for all articles that defined vHIT, compared vHIT with another clinical test, and studied the efficacy of vHIT as diagnostic tools with vestibular disease. 37 articles about vHIT were reviewed. All articles studied the vHIT in English and French languages up to May 2015 were included in the review. Editorial articles or short comments, conference abstracts, animal studies, and language restriction were excluded from the review. Four systems were used in the literature to do the vHIT. vHIT is physiological quick test, which studied the VOR at high frequency of each semicircular canal by calculating the duration ratio between the head impulse and gaze deviation. vHIT is more sensitive than clinical head impulse test (cHIT), especially in patient with isolated covert saccades. vHIT test is diagnostic of vestibular weakness by gain reduction and the appearance of overt and covert saccades. If the vHIT is normal, then caloric test is mandatory to rule out a peripheral origin of vertigo. It is recommended to test each semicircular canal, as isolated vertical canal weakness was identified in the literature. More investigation would be required to determine the evolution of the VOR gain with the progression of the vestibular disease.

Development of a head-phantom and measurement setup for lightning effects.

PubMed

Machts, Rene; Hunold, Alexander; Leu, Carsten; Haueisen, Jens; Rock, Michael

2016-08-01

Direct lightning strikes to human heads lead to various effects ranging from Lichtenberg figures, over loss of consciousness to death. The evolution of the induced current distribution in the head is of great interest to understand the effect mechanisms. This work describes a technique to model a simplified head-phantom to investigate effects during direct lightning strike. The head-phantom geometry, conductive and dielectric parameters were chosen similar to that of a human head. Three layers (brain, skull, and scalp) were created for the phantom using agarose hydrogel doped with sodium chloride and carbon. The head-phantom was tested on two different impulse generators, which reproduce approximate lightning impulses. The effective current and the current distribution in each layer were analyzed. The biggest part of the current flowed through the brain layer, approx. 70 % in cases without external flashover. Approx. 23 % of the current flowed through skull layer and 6 % through the scalp layer. However, the current decreased within the head-phantom to almost zero after a complete flashover on the phantom occurred. The flashover formed faster with a higher impulse current level. Exposition time of current through the head decreases with a higher current level of the lightning impulse. This mechanism might explain the fact that people can survive a lightning strike. The experiments help to understand lightning effects on humans.

Effect of aging and direction of impulse in video head impulse test.

PubMed

Kim, Tae Hwan; Kim, Min-Beom

2017-09-12

The aim of this study was to identify the difference of gain value in the video head impulse test (vHIT) according to the age of the patient and the direction of the impulse. All participants were subjected to vHIT with horizontal semicircular canal (HSCC). vHIT with vertical canal (posterior and anterior semicircular canal [PSCC and ASCC]) additionally was performed in 434 participants. The mean vestibulo-ocular reflex (VOR) gain was maintained in patients in the HSCC at below 70 years (1.025 ± 0.08) and in the vertical canal at below 80 years (PSCC: 0.965 ± 0.12, ASCC: 0.975 ± 0.14). However, the decrease of VOR gain was significant in patients over 70 years in the HSCC (0.978 ± 0.35, P < .001) and in patients over 80 years in the vertical canal (PSCC: 0.828 ± 0.16, ASCC: 0.851 ± 0.13, P < .001). In addition, a VOR gain of rightward impulse was higher than the leftward impulse, but there was no difference based on the direction of impulse in the vertical impulse test. VOR gain declines with increasing age, over 70 years on the horizontal canal, and over 80 years on the vertical canal. Additionally, horizontal VOR gain of rightward impulse was higher than the leftward impulse in right-eye recordings only, but the vertical canal showed no difference of gain according to the direction of impulse. 2b. Laryngoscope, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

[Assessment of the horizontal semicircular canal function after cochlear implantation by video head impulse test and caloric test].

PubMed

Zeng, Jie; Huang, Hong Ming; Wang, Xiao Qian; Zhong, Kai Bang; Wu, Pei Na

2018-01-20

Objective: To analyze the functional change of horizontal semicircular canals after cochlear implantation. Method: Eighteen patients were enrolled in this study.Their vestibular function was evaluated by using the caloric test and video head impulse test before and one week,one month after CI surgery,respectively.The unilateral weakness(UW),slow phase velocity(SPV)in caloric test and gain in video head impulse test(vHIT-G)were observed.Caloric test was abnormal when UW>25% or SPV mean<6°/s,while vHIT was abnormal when vHIT-G<0.8. Result: The SPV of the implanted ear were[(10.36±8.01)°/s;(14.77±14.24)°/s]pre-operatively,[(6.45±7.52)°/s;(5.14±4.67)°/s]1 week post-operatively and[(6.05±3.86)°/s;(6.27±4.17)°/s]1 month post-operatively.Statistically significant difference( P <0.05)was found between pre-and post-operative period.The vHIT-G of the implanted ear were(0.73±0.33)pre-operatively,(0.65±0.32)1 week post-operatively and(0.71±0.36)1 month post-operatively.There was no statistically significant difference of vHIT-G between preand post-operative period( P (pre-operative/1 week post-operative)=0.084, P (pre-operative/1 month post-operative)=0.679).Four patients presented with vertigo and one of them manifested slight unsteadiness post-operatively.All symptoms resolved within 7 days.These symptoms had no correlate with age,gender,implantedear and results of vestibular test. Conclusion: Cochlear implantation can affect the horizontal semicircular canal function,and the video head impulse test and caloric test should be used in a complementary fashion.

Are juvenile domestic pigs (Sus scrofa domestica) sensitive to the attentive states of humans?--The impact of impulsivity on choice behaviour.

PubMed

Nawroth, Christian; Ebersbach, Mirjam; von Borell, Eberhard

2013-06-01

Previous studies have shown that apes, dogs and horses seem to be able to attribute attentive states to humans. Subjects had to choose between two persons: one who was able to see the animal and one who was not. Using a similar paradigm, we tested a species that does not rely strongly on visual cues, the domestic pig (Sus scrofa domestica). Subjects could choose between two unfamiliar persons, with only one showing attention, in three different conditions (body, head away, body turned - head front). Subjects (n=16) only showed a tendency towards the attentive human in the head away condition. However, by pooling those two conditions where the position of the human head was the only salient cue, we found a significant preference for the attentive person. Moreover, two approach styles could be distinguished - an impulsive style with short response times and a non-impulsive style where response times were relatively long. With the second approach style, pigs chose the attentive person significantly more often than expected by chance level, which was not the case when subjects chose impulsively. These first results suggest that pigs are able to use head cues to discriminate between different attentive states of humans. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparison of Video Head Impulse Test (vHIT) Gains Between Two Commercially Available Devices and by Different Gain Analytical Methods.

PubMed

Lee, Sang Hun; Yoo, Myung Hoon; Park, Jun Woo; Kang, Byung Chul; Yang, Chan Joo; Kang, Woo Suk; Ahn, Joong Ho; Chung, Jong Woo; Park, Hong Ju

2018-06-01

To evaluate whether video head impulse test (vHIT) gains are dependent on the measuring device and method of analysis. Prospective study. vHIT was performed in 25 healthy subjects using two devices simultaneously. vHIT gains were compared between these instruments and using five different methods of comparing position and velocity gains during head movement intervals. The two devices produced different vHIT gain results with the same method of analysis. There were also significant differences in the vHIT gains measured using different analytical methods. The gain analytic method that compares the areas under the velocity curve (AUC) of the head and eye movements during head movements showed lower vHIT gains than a method that compared the peak velocities of the head and eye movements. The former method produced the vHIT gain with the smallest standard deviation among the five procedures tested in this study. vHIT gains differ in normal subjects depending on the device and method of analysis used, suggesting that it is advisable for each device to have its own normal values. Gain calculations that compare the AUC of the head and eye movements during the head movements show the smallest variance.

The Video Head Impulse Test to Assess the Efficacy of Vestibular Implants in Humans

PubMed Central

Guinand, Nils; Van de Berg, Raymond; Cavuscens, Samuel; Ranieri, Maurizio; Schneider, Erich; Lucieer, Floor; Kingma, Herman; Guyot, Jean-Philippe; Pérez Fornos, Angélica

2017-01-01

The purpose of this study was to evaluate whether it is possible to restore the high-frequency angular vestibulo-ocular reflex (aVOR) in patients suffering from a severe bilateral vestibulopathy (BV) and implanted with a vestibular implant prototype. Three patients (S1–3) participated in the study. They received a prototype vestibular implant with one to three electrode branches implanted in the proximity of the ampullary branches of the vestibular nerve. Five electrodes were available for electrical stimulation: one implanted in proximity of the left posterior ampullary nerve in S1, one in the left lateral and another one in the superior ampullary nerves in S2, and one in the right lateral and another one in the superior ampullary nerves in S3. The high-frequency aVOR was assessed using the video head impulse test (EyeSeeCam; EyeSeeTec, Munich, Germany), while motion-modulated electrical stimulation was delivered via one of the implanted vestibular electrodes at a time. aVOR gains were compared to control measurements obtained in the same patients when the device was not activated. In three out of the five tested electrodes the aVOR gain increased monotonically with increased stimulation strength when head impulses were delivered in the plane of the implanted canal. In these cases, gains ranging from 0.4 to values above 1 were measured. A “reversed” aVOR could also be generated when inversed stimulation paradigms were used. In most cases, the gain for excitatory head impulses was superior to that recorded for inhibitory head impulses, consistent with unilateral vestibular stimulation. Improvements of aVOR gain were generally accompanied by a concomitant decrease of corrective saccades, providing additional evidence of an effective aVOR. High inter-electrode and inter-subject variability were observed. These results, together with previous research, demonstrate that it is possible to restore the aVOR in a broad frequency range using motion-modulated electrical stimulation of the vestibular afferents. This provides additional encouraging evidence of the possibility of achieving a useful rehabilitation alternative for patients with BV in the near future. PMID:29184530

Saccadic entropy of head impulses in acute unilateral vestibular loss.

PubMed

Hsieh, Li-Chun; Lin, Hung-Ching; Lee, Guo-She

2017-10-01

To evaluate the complexity of vestibular-ocular reflex (VOR) in patients with acute unilateral vestibular loss (AUVL) via entropy analysis of head impulses. Horizontal head impulse test (HIT) with high-velocity alternating directions was used to evaluate 12 participants with AUVL and 16 healthy volunteers. Wireless electro-oculography and electronic gyrometry were used to acquire eye positional signals and head velocity signals. The eye velocity signals were then obtained through differentiation, band-pass filtering. The approximate entropy of eye velocity to head velocity (R ApEn ) was used to evaluate chaos property. VOR gain, gain asymmetry ratio, and R ApEn asymmetry ratio were also used to compare the groups. For the lesion-side HIT of the patient group, the mean VOR gain was significantly lower and the mean R ApEn was significantly greater compared with both nonlesion-side HIT and healthy controls (p < 0.01, one-way analysis of variance). Both the R ApEn asymmetry ratio and gain asymmetry ratio of the AUVL group were significantly greater compared with those of the control group (p < 0.05, independent sample t test). Entropy and gain analysis of HIT using wireless electro-oculography system could be used to detect the VOR dysfunctions of AUVL and may become effective methods for evaluating vestibular disorders. Copyright © 2017. Published by Elsevier B.V.

Clinical experience with video Head Impulse Test in children.

PubMed

Hülse, Roland; Hörmann, Karl; Servais, Jerôme José; Hülse, Manfred; Wenzel, Angela

2015-08-01

A standardized diagnostic protocol for children's vestibular assessment is still missing in daily clinical life. As rotatory chair testing and caloric test are usually not tolerated well by children, the aim of our study was not only to evaluate the importance and practicability of the video head impulse test performed in children with and without balance problems, but also to outline a diagnostic algorithm for children with balance problems. Fifty-five children aged 3-16 years have been included in this prospective monocentric study. Balance was assessed using results from health screening examinations of the participants and results from a specific dizziness questionnaire for children. The children were then divided in two groups: group I without any sign of vestibular development disorder and group II with possible signs for a pathological equilibrium development. Horizontal vestibulo-ocular reflex (HVOR) was assessed using a video-oculography system device (EyeSeeCam(©)). Gain at 40, 60, and 80ms and gain variance has been measured. Furthermore, it was evaluated how calibration of the system was tolerated by the participants, how the test itself was accomplishable in children, and which difficulties arose during testing. Reproducible test results were accomplished in 42 children (75%). Children with no balance problems in history showed a median gain of 1.02 (±0.28). A significant gain reduction between 40 and 80ms was found (P<0.05). Catch-up saccades were found in none of the children. Children with balance problems had a significantly reduced gain. (0.47±0.3; P<0.05) In this group, catch-up saccades could be detected in 4 out of 6 patients. For both groups, performing the test approximately took 20min, which is significantly longer than in adults (P<0.05). Calibration of the system with laser dots was easily doable in children aged 6 and older, whereas children between 3 and 5 years had better calibration results using colorful little icons. Video head impulse test is a sensitive and efficient vestibular test in children, which is tolerated well by children aged 3-16 years. Therefore, video head impulse test can be easily used as a screening tool to detect vestibular dysfunction in the pediatric population. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Characterizing high-velocity angular vestibulo-ocular reflex function in service members post-blast exposure

PubMed Central

Scherer, Matthew R.; Shelhamer, Mark J.; Schubert, Michael C.

2011-01-01

Blasts (explosions) are the most common mechanism of injury in modern warfare. Traumatic brain injury (TBI) and dizziness are common sequelae associated with blasts, and many service members (SMs) report symptoms worsen with activity. The purpose of this study was to measure angular vestibulo-ocular reflex gain (aVOR) of blast-exposed SMs with TBI during head impulse testing. We also assessed their symptoms during exertion. Twenty-four SMs recovering from TBI were prospectively assigned to one of two groups based on the presence or absence of dizziness. Wireless monocular scleral search coil and rate sensor were used to characterize active and passive yaw and pitch head and eye rotations. Visual analog scale (VAS) was used to monitor symptoms during fast walking/running. For active yaw head impulses, aVOR gains were significantly lower in the symptomatic group (0.79 ± 0.15) versus asymptomatic (0.87 ± 0.18), but not for passive head rotation. For pitch head rotation, the symptomatic group had both active (0.915 ± 0.24) and passive (0.878 ± 0.22) aVOR gains lower than the asymptomatic group (active 1.03 ± 0.27, passive 0.97 ± 0.23). Some SMs had elevated aVOR gain. VAS scores for all symptoms were highest during exertion. Our data suggest symptomatic SMs with TBI as a result of blast have varied aVOR gain during high-velocity head impulses and provide compelling evidence of pathology affecting the vestibular system. Potential loci of injury in this population include the following: disruption of pathways relaying vestibular efference signals, differential destruction of type I vestibular hair cells, or selective damage to irregular afferent pathways—any of which may explain the common discrepancy between reports of vestibular-like symptoms and laboratory testing results. significantly reduced pitch aVOR in symptomatic SMs and peak symptom severity during exertional testing support earlier findings in the chronic blast-exposed active duty SMs. PMID:21113582

Axis of Eye Rotation Changes with Head-Pitch Orientation during Head Impulses about Earth-Vertical

PubMed Central

Schubert, Michael C.; Clendaniel, Richard A.; Carey, John P.; Della Santina, Charles C.; Minor, Lloyd B.; Zee, David S.

2006-01-01

The goal of this study was to assess how the axis of head rotation, Listing's law, and eye position influence the axis of eye rotation during brief, rapid head rotations. We specifically asked how the axis of eye rotation during the initial angular vestibuloocular reflex (VOR) changed when the pitch orientation of the head relative to Earth-vertical was varied, but the initial position of the eye in the orbit and the orientation of Listing's plane with respect to the head were fixed. We measured three-dimensional eye and head rotation axes in eight normal humans using the search coil technique during head-and-trunk (whole-body) and head-on-trunk (head-only) “impulses” about an Earth-vertical axis. The head was initially oriented at one of five pitch angles (30° nose down, 15° nose down, 0°, 15° nose up, 30° nose up). The fixation target was always aligned with the nasooccipital axis. Whole-body impulses were passive, unpredictable, manual, rotations with peak-amplitude of ∼20°, peak-velocity of ∼80°/s, and peak-acceleration of ∼1000°/s2. Head-only impulses were also passive, unpredictable, manual, rotations with peak-amplitude of ∼20°, peak-velocity of ∼150°/s, and peak-acceleration of ∼3000°/s2. During whole-body impulses, the axis of eye rotation tilted in the same direction, and by an amount proportional (0.51 ± 0.09), to the starting pitch head orientation (P < 0.05). This proportionality constant decreased slightly to 0.39 ± 0.08 (P < 0.05) during head-only impulses. Using the head-only impulse data, with the head pitched up, we showed that only 50% of the tilt in the axis of eye rotation could be predicted from vectorial summation of the gains (eye velocity/head velocity) obtained for rotations about the pure yaw and roll head axes. Thus, even when the orientation of Listing's plane and eye position in the orbit are fixed, the axis of eye rotation during the VOR reflects a compromise between the requirements of Listing's law and a perfectly compensatory VOR. PMID:16552499

Effect of neck muscle strength and anticipatory cervical muscle activation on the kinematic response of the head to impulsive loads.

PubMed

Eckner, James T; Oh, Youkeun K; Joshi, Monica S; Richardson, James K; Ashton-Miller, James A

2014-03-01

Greater neck strength and activating the neck muscles to brace for impact are both thought to reduce an athlete's risk of concussion during a collision by attenuating the head's kinematic response after impact. However, the literature reporting the neck's role in controlling postimpact head kinematics is mixed. Furthermore, these relationships have not been examined in the coronal or transverse planes or in pediatric athletes. In each anatomic plane, peak linear velocity (ΔV) and peak angular velocity (Δω) of the head are inversely related to maximal isometric cervical muscle strength in the opposing direction (H1). Under impulsive loading, ΔV and Δω will be decreased during anticipatory cervical muscle activation compared with the baseline state (H2). Descriptive laboratory study. Maximum isometric neck strength was measured in each anatomic plane in 46 male and female contact sport athletes aged 8 to 30 years. A loading apparatus applied impulsive test forces to athletes' heads in flexion, extension, lateral flexion, and axial rotation during baseline and anticipatory cervical muscle activation conditions. Multivariate linear mixed models were used to determine the effects of neck strength and cervical muscle activation on head ΔV and Δω. Greater isometric neck strength and anticipatory activation were independently associated with decreased head ΔV and Δω after impulsive loading across all planes of motion (all P < .001). Inverse relationships between neck strength and head ΔV and Δω presented moderately strong effect sizes (r = 0.417 to r = 0.657), varying by direction of motion and cervical muscle activation. In male and female athletes across the age spectrum, greater neck strength and anticipatory cervical muscle activation ("bracing for impact") can reduce the magnitude of the head's kinematic response. Future studies should determine whether neck strength contributes to the observed sex and age group differences in concussion incidence. Neck strength and impact anticipation are 2 potentially modifiable risk factors for concussion. Interventions aimed at increasing athletes' neck strength and reducing unanticipated impacts may decrease the risk of concussion associated with sport participation.

Preoperative vestibular assessment protocol of cochlear implant surgery: an analytical descriptive study.

PubMed

Bittar, Roseli Saraiva Moreira; Sato, Eduardo Setsuo; Ribeiro, Douglas Jósimo Silva; Tsuji, Robinson Koji

Cochlear implants are undeniably an effective method for the recovery of hearing function in patients with hearing loss. To describe the preoperative vestibular assessment protocol in subjects who will be submitted to cochlear implants. Our institutional protocol provides the vestibular diagnosis through six simple tests: Romberg and Fukuda tests, assessment for spontaneous nystagmus, Head Impulse Test, evaluation for Head Shaking Nystagmus and caloric test. 21 patients were evaluated with a mean age of 42.75±14.38 years. Only 28% of the sample had all normal test results. The presence of asymmetric vestibular information was documented through the caloric test in 32% of the sample and spontaneous nystagmus was an important clue for the diagnosis. Bilateral vestibular areflexia was present in four subjects, unilateral arreflexia in three and bilateral hyporeflexia in two. The Head Impulse Test was a significant indicator for the diagnosis of areflexia in the tested ear (p=0.0001). The sensitized Romberg test using a foam pad was able to diagnose severe vestibular function impairment (p=0.003). The six clinical tests were able to identify the presence or absence of vestibular function and function asymmetry between the ears of the same individual. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Characterizing high-velocity angular vestibulo-ocular reflex function in service members post-blast exposure.

PubMed

Scherer, Matthew R; Shelhamer, Mark J; Schubert, Michael C

2011-02-01

Blasts (explosions) are the most common mechanism of injury in modern warfare. Traumatic brain injury (TBI) and dizziness are common sequelae associated with blasts, and many service members (SMs) report symptoms worsen with activity. The purpose of this study was to measure angular vestibulo-ocular reflex gain (aVOR) of blast-exposed SMs with TBI during head impulse testing. We also assessed their symptoms during exertion. Twenty-four SMs recovering from TBI were prospectively assigned to one of two groups based on the presence or absence of dizziness. Wireless monocular scleral search coil and rate sensor were used to characterize active and passive yaw and pitch head and eye rotations. Visual analog scale (VAS) was used to monitor symptoms during fast walking/running. For active yaw head impulses, aVOR gains were significantly lower in the symptomatic group (0.79 ± 0.15) versus asymptomatic (0.87 ± 0.18), but not for passive head rotation. For pitch head rotation, the symptomatic group had both active (0.915 ± 0.24) and passive (0.878 ± 0.22) aVOR gains lower than the asymptomatic group (active 1.03 ± 0.27, passive 0.97 ± 0.23). Some SMs had elevated aVOR gain. VAS scores for all symptoms were highest during exertion. Our data suggest symptomatic SMs with TBI as a result of blast have varied aVOR gain during high-velocity head impulses and provide compelling evidence of pathology affecting the vestibular system. Potential loci of injury in this population include the following: disruption of pathways relaying vestibular efference signals, differential destruction of type I vestibular hair cells, or selective damage to irregular afferent pathways-any of which may explain the common discrepancy between reports of vestibular-like symptoms and laboratory testing results. Significantly reduced pitch aVOR in symptomatic SMs and peak symptom severity during exertional testing support earlier findings in the chronic blast-exposed active duty SMs.

Video Head Impulse Test for Early Diagnosis of Vestibular Neuritis Among Acute Vertigo.

PubMed

Guan, Qiongfeng; Zhang, Lisan; Hong, Wenke; Yang, Yi; Chen, Zhaoying; Lu, Peilin; Zhang, Dan; Hu, Xingyue

2017-09-01

This study assesses the value of the video head impulse test (vHIT) for early diagnosis of vestibular neuritis (VN) among acute vertigo. Thirty-three cases of vestibular neuritis (VN), 96 patients with other acute vertigo (AV), and 50 cases of normal controls used vHIT to quantitatively test a pair of horizontal vestibulo-ocular reflection (VOR) gains, two pairs of vertical VOR gains, and the corresponding three pairs of VOR gain asymmetry. The peculiarity of VOR gains in VN and the differences between VN and other AV, normal controls by vHIT, were collected and analyzed. There were statistically significant differences in the three pairs of VOR gains asymmetry between VN and other AV, and normal controls (P<0.01). The sensitivity was 87.9% and specificity was 94.3% in differentiating VN from normal and other acute vertigo by vHIT. This study shows vHIT has advantages in the diagnosis of VN in acute vertigo with good sensitivity and specificity and indicates a widespread clinical application.

Instrumental head impulse test changes after intratympanic gentamicin for unilateral definite Ménière's disease: A systematic review and meta-analysis.

PubMed

Marques, Pedro Santos; Dias, Claudia Camila; Perez-Fernandez, Nicolas; Spratley, Jorge

2018-02-02

To estimate how much could intratympanic gentamicin (ITG) interfere with the vestibular-ocular reflex (VOR) parameters on instrumental head impulse test (HIT), either with scleral search coil or video head impulse test and, eventually, foresee the control of vertigo crisis in unilateral intractable Ménière's disease (MD). A literature search was conducted in PubMed, Scopus, Web of Science and Cochrane search engines. The search terms used were "vestibular ocular reflex", "head impulse test", "gentamicin," and "Meniere's disease". Limitations included text availability to be full text, species to be humans and language to be English. All study types were included. 89 articles were screened identifying four eligible studies were identified. Studies were included after consensus of the authors. Meta-analysis was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data was analysed using Review Manager software. Instrumental HIT, after ITG for MD, demonstrated, in the treated ear, a decreased gain in the horizontal, posterior and superior semicircular canals (SCC), of 0.36 (0.26; 0.47; 95% CI), 0.35 (0.22; 0.48; 95% CI) and 0.28 (0.21; 0.35; 95% CI), respectively. Gain asymmetry increases between the treated and non-treated ear of 23.78 (7.22; 40.35; 95% CI), 32.01 (12.27; 51.76; 95% CI) and 17.49 (9.99; 24.99; 95% CI), were similarly detected in the horizontal, posterior and superior SCC, respectively. Significantly smaller gain values after the first treatment were observed for a single injection group versus multiple injection group in the horizontal (p=0.002) and superior SCCs (p=0.016). Instrumental HIT is effective in evaluating the SCC function after ITG for intractable unilateral MD. VOR gain changes in the direction of the treated ear in the three SCC have been clearly registered. An increased reduction of the VOR gain in the horizontal and anterior SCC also seemed to foresee the control of vertigo crisis. Still, after meta-analysis, the small number of patients' data available did not allow to define a treatment end-point value. This review also indicated that further and better-designed studies are warranted. Copyright © 2018 Elsevier B.V. All rights reserved.

False-Positive Head-Impulse Test in Cerebellar Ataxia

PubMed Central

Kremmyda, Olympia; Kirchner, Hanni; Glasauer, Stefan; Brandt, Thomas; Jahn, Klaus; Strupp, Michael

2012-01-01

The objective of this study was to compare the findings of the bedside head-impulse test (HIT), passive head rotation gain, and caloric irrigation in patients with cerebellar ataxia (CA). In 16 patients with CA and bilaterally pathological bedside HIT, vestibuloocular reflex (VOR) gains were measured during HIT and passive head rotation by scleral search coil technique. Eight of the patients had pathologically reduced caloric responsiveness, while the other eight had normal caloric responses. Those with normal calorics showed a slightly reduced HIT gain (mean ± SD: 0.73 ± 0.15). In those with pathological calorics, gains 80 and 100 ms after the HIT as well as the passive rotation VOR gains were significantly lower. The corrective saccade after head turn occurred earlier in patients with pathological calorics (111 ± 62 ms after onset of the HIT) than in those with normal calorics (191 ± 17 ms, p = 0.0064). We identified two groups of patients with CA: those with an isolated moderate HIT deficit only, probably due to floccular dysfunction, and those with combined HIT, passive rotation, and caloric deficit, probably due to a peripheral vestibular deficit. From a clinical point of view, these results show that the bedside HIT alone can be false-positive for establishing a diagnosis of a bilateral peripheral vestibular deficit in patients with CA. PMID:23162531

Reduced order modeling of head related transfer functions for virtual acoustic displays

NASA Astrophysics Data System (ADS)

Willhite, Joel A.; Frampton, Kenneth D.; Grantham, D. Wesley

2003-04-01

The purpose of this work is to improve the computational efficiency in acoustic virtual applications by creating and testing reduced order models of the head related transfer functions used in localizing sound sources. State space models of varying order were generated from zero-elevation Head Related Impulse Responses (HRIRs) using Kungs Single Value Decomposition (SVD) technique. The inputs to the models are the desired azimuths of the virtual sound sources (from minus 90 deg to plus 90 deg, in 10 deg increments) and the outputs are the left and right ear impulse responses. Trials were conducted in an anechoic chamber in which subjects were exposed to real sounds that were emitted by individual speakers across a numbered speaker array, phantom sources generated from the original HRIRs, and phantom sound sources generated with the different reduced order state space models. The error in the perceived direction of the phantom sources generated from the reduced order models was compared to errors in localization using the original HRIRs.

Reliability and comparison of gain values with occurrence of saccades in the EyeSeeCam video head impulse test (vHIT).

PubMed

Korsager, Leise Elisabeth Hviid; Schmidt, Jesper Hvass; Faber, Christian; Wanscher, Jens Højberg

2016-12-01

The vHIT (video head impulse test) investigates the vestibular function in two ways: a VOR (vestibulo-ocular reflex) gain value and a head impulse diagram. From the diagram covert and overt saccades can be detected. Evaluation of the vestibular function based on vHIT depends on both parameters. There is a lack of knowledge regarding the reliability of the two parameters. The objective was to investigate the reliability of vHIT by comparing gain values between examiners on the same subjects, and to see how differences affected the occurrence of saccades. 25 subjects who had undergone cochlear implant (CI) surgery. Subjects were tested using the vHIT by two of four different examiners. Two judges interpreted the occurrence of saccades in the diagram. VOR gain values and the occurrence of saccades in the diagram. Differences in gain values between examiners varied from 0.2 to 0.58 with an average of 0.14 (95 % CI 0.12-0.16) on the right ear and 0.17 (95 % CI 0.15-0.19) on the left ear. Occurrences of saccades in the same patient were reproduced in 93 % of the cases by all examiners. Kappa's coefficient on the occurrence of saccades was 0.83. Interclass correlation coefficient (ICC) of the gain values between examiners ranged from 0.62 to 0.70. Differences in gain values amongst examiners did not seem to affect the occurrence of saccades in the same patient. The occurrence of saccades, therefore, seems to be more reliable than the gain value in the evaluation of the vestibular function. Interpretation of vHIT results should, therefore, first depend on the occurrence of saccades and second on the gain value.

[Preliminary application of video head impulse test in the diagnosis of vertigo].

PubMed

Zhang, Yanmei; Chen, Siqi; Zhong, Zhen; Chen, Li; Wu, Yuanding; Zhao, Guiping; Liu, Yuhe

2015-06-01

To investigate clinical application of head impulse test with video recording eye movements in the diagnosis of vertigo. The video head impulse test(vHIT) was used to measure the eye saccades and velocity gain in 95 patients with vertigo which were divided into two groups, peripheral vertigo (47 cases) and central vertigo(48 cases); the characteristics of eye saccades and velocity gain of six semicircular canals in different patients with vertigo were analyzed, and were compared between the two groups. The vHIT result in patients with peripheral vertigo: in 22 patients (23 affected ears) with Meniere's disease, 21 ears were abnormal (91. 3%); the vHIT results in 4 patients with vestibular schwannoma, 2 patients with vestibular neuritis, 5 patients with delayed endolymphatic hydrops, 6 patients with sudden hearing loss accompanied vertigo, and 8 patients with vestibular dysfunction, were abnormal with correct saccades and/or lower velocity gain of vHIT. The abnormal vHIT results were also found in 35 of 48 patients (72. 9%) with central vertigo, which including posterior cerebral circulation ischemia(7 patients), cerebral infarction/stroke(6 patients), and dizziness with vertigo(17 patients) and others(18 patients). Abnormal rate of vHIT in patients with peripheral vertigo was 95. 7% (45/47), which was significantly higher than that (72. 9%) in patients with central vertigo. It is easy to perform the vHIT which without adverse reactions. We can record high-frequency characteristics of vestibular-ocular reflex among six semicircular canals through vHIT. The vHIT results which show the function of vestibular ocular reflex in different diseases with vertigo, can help discriminate peripheral vertigo from central vertigo, and it is a practical assessment method for vertigo.

Are Covert Saccade Functionally Relevant in Vestibular Hypofunction?

PubMed

Hermann, R; Pelisson, D; Dumas, O; Urquizar, Ch; Truy, E; Tilikete, C

2018-06-01

The vestibulo-ocular reflex maintains gaze stabilization during angular or linear head accelerations, allowing adequate dynamic visual acuity. In case of bilateral vestibular hypofunction, patients use saccades to compensate for the reduced vestibulo-ocular reflex function, with covert saccades occurring even during the head displacement. In this study, we questioned whether covert saccades help maintain dynamic visual acuity, and evaluated which characteristic of these saccades are the most relevant to improve visual function. We prospectively included 18 patients with chronic bilateral vestibular hypofunction. Subjects underwent evaluation of dynamic visual acuity in the horizontal plane as well as video recording of their head and eye positions during horizontal head impulse tests in both directions (36 ears tested). Frequency, latency, consistency of covert saccade initiation, and gain of covert saccades as well as residual vestibulo-ocular reflex gain were calculated. We found no correlation between residual vestibulo-ocular reflex gain and dynamic visual acuity. Dynamic visual acuity performance was however positively correlated with the frequency and gain of covert saccades and negatively correlated with covert saccade latency. There was no correlation between consistency of covert saccade initiation and dynamic visual acuity. Even though gaze stabilization in space during covert saccades might be of very short duration, these refixation saccades seem to improve vision in patients with bilateral vestibular hypofunction during angular head impulses. These findings emphasize the need for specific rehabilitation technics that favor the triggering of covert saccades. The physiological origin of covert saccades is discussed.

Impact of Target Distance, Target Size, and Visual Acuity on the Video Head Impulse Test.

PubMed

Judge, Paul D; Rodriguez, Amanda I; Barin, Kamran; Janky, Kristen L

2018-05-01

The video head impulse test (vHIT) assesses the vestibulo-ocular reflex. Few have evaluated whether environmental factors or visual acuity influence the vHIT. The purpose of this study was to evaluate the influence of target distance, target size, and visual acuity on vHIT outcomes. Thirty-eight normal controls and 8 subjects with vestibular loss (VL) participated. vHIT was completed at 3 distances and with 3 target sizes. Normal controls were subdivided on the basis of visual acuity. Corrective saccade frequency, corrective saccade amplitude, and gain were tabulated. In the normal control group, there were no significant effects of target size or visual acuity for any vHIT outcome parameters; however, gain increased as target distance decreased. The VL group demonstrated higher corrective saccade frequency and amplitude and lower gain as compared with controls. In conclusion, decreasing target distance increases gain for normal controls but not subjects with VL. Preliminarily, visual acuity does not affect vHIT outcomes.

Multi-channel spatialization systems for audio signals

NASA Technical Reports Server (NTRS)

Begault, Durand R. (Inventor)

1993-01-01

Synthetic head related transfer functions (HRTF's) for imposing reprogrammable spatial cues to a plurality of audio input signals included, for example, in multiple narrow-band audio communications signals received simultaneously are generated and stored in interchangeable programmable read only memories (PROM's) which store both head related transfer function impulse response data and source positional information for a plurality of desired virtual source locations. The analog inputs of the audio signals are filtered and converted to digital signals from which synthetic head related transfer functions are generated in the form of linear phase finite impulse response filters. The outputs of the impulse response filters are subsequently reconverted to analog signals, filtered, mixed, and fed to a pair of headphones.

Multi-channel spatialization system for audio signals

NASA Technical Reports Server (NTRS)

Begault, Durand R. (Inventor)

1995-01-01

Synthetic head related transfer functions (HRTF's) for imposing reprogramable spatial cues to a plurality of audio input signals included, for example, in multiple narrow-band audio communications signals received simultaneously are generated and stored in interchangeable programmable read only memories (PROM's) which store both head related transfer function impulse response data and source positional information for a plurality of desired virtual source locations. The analog inputs of the audio signals are filtered and converted to digital signals from which synthetic head related transfer functions are generated in the form of linear phase finite impulse response filters. The outputs of the impulse response filters are subsequently reconverted to analog signals, filtered, mixed and fed to a pair of headphones.

Impulse Pump

DTIC Science & Technology

2016-06-17

APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention relates to an impulse pump for generating...impulse pump 15. The sleeve bearings 98 are affixed to the head block 90 to ease axial motion while the plunger 72 is under torsional loads. [0041

Vergence-mediated modulation of the human horizontal vestibulo-ocular reflex is eliminated by a partial peripheral gentamicin lesion.

PubMed

Migliaccio, Americo A; Minor, Lloyd B; Carey, John P

2004-11-01

The angular vestibulo-ocular reflex normally has an increased response during vergence on a near target. Surgical unilateral vestibular deafferentation reduces the horizontal vestibulo-ocular reflex (VOR) in response to far target viewing and eliminates this vergence effect. Intratympanic gentamicin treatment reduces VOR gain during far viewing, but the reduction is less severe than that after unilateral vestibular deafferentation. We sought to determine how gentamicin would affect vergence-mediated modulation of the VOR. The VOR in response to passive head impulses in the horizontal plane while viewing a far (124 cm) or near (15 cm) target was evaluated in 11 subjects following intratympanic gentamicin treatment. Three of these subjects had also been tested immediately prior to receiving gentamicin. The impulses were low amplitude (approximately 20 degrees ), high velocity (approximately 150 degrees /s), high acceleration (approximately 3,000 degrees /s2) horizontal head rotations administered manually by the investigator. Binocular eye and head velocity were recorded using the scleral search coil technique. The VOR gain was defined as eye velocity divided by inverted head velocity. Prior to intratympanic gentamicin, the VOR gain during rotations to either side was symmetric and showed the same vergence-mediated increase. Following gentamicin, head impulses towards the untreated side yielded VOR gains of 0.91+/-0.12 while viewing a far target and 1.27+/-0.22 while viewing a near target, an increase of 33%. Head impulses towards the treated side produced a hypometric VOR with no increase between far and near viewing. The average latency of the VOR was 7.6+/-2.5 ms towards the untreated side for either near or far viewing and 20.7+/-13.1 ms towards the treated side for either near or far viewing. Our findings show that a peripheral lesion caused by gentamicin does not ablate the VOR but does eliminate a component of the vestibular signal that is necessary for vergence-mediated modulation of the VOR. Gentamicin has preferential toxicity for the hair cells in the central zone of the crista, where irregular afferents predominate. Our findings are consistent with the hypothesis that irregular afferents provide the necessary signal for vergence-mediated modulation of the VOR.

Intra- and Interexaminer Variability of Two Separate Video Head Impulse Test Systems Assessing All Six Semicircular Canals.

PubMed

Abrahamsen, Emil Riis; Christensen, Ann-Eva; Hougaard, Dan Dupont

2018-02-01

To evaluate intra- and interexaminer variability of the video Head Impulse Test (v-HIT) when assessing all six semicircular canals (SCCs) of two separate v-HIT systems. Prospective study. Department of Otolaryngology, Head and Neck Surgery, Aalborg University Hospital, Denmark. One hundred twenty healthy subjects. Four separate tests of all six SCCs with either system A or system B. Two examiners tested all subjects twice. Pretest randomization included type of v-HIT system, order of paired SCC testing, as well as initial examiner. Gain values and the presence of pathological saccades were registered. Ninety-five percent limits of agreement (LOAs) were calculated for both intra- and interexaminer variability. Adding or subtracting the value from the mean difference achieves the upper and lower bound LOA. Ninety-five percent of the differences lie within these limits. Interexaminer reliability: System A: LOAs between 0.13 and 0.24 for the horizontal SCCs and between 0.42 and 0.74 for the vertical SCCs. System B: LOAs between 0.09 and 0.13 for the horizontal SCCs and between 0.13 and 0.20 for the vertical SCCs. Intraexaminer reliability: System A: LOAs were 0.19 and 0.14 for the horizontal SCCs and varied from 0.43 to 0.53 for the vertical SCCs. System B: LOAs were 0.14 for the horizontal SCCs and varied from 0.13 to 0.22 for the vertical SCCs. Horizontal SCC testing: both v-HIT systems displayed good intra- and interexaminer variability. Vertical SCC testing: System B displayed good intra- and interexaminer variability whereas the opposite was true with system A.

Comparison of Video Head Impulse Test and Caloric Reflex Test in advanced unilateral definite Menière's disease.

PubMed

Rubin, F; Simon, F; Verillaud, B; Herman, P; Kania, R; Hautefort, C

2018-06-01

There have been very few studies of the Video Head Impulse Test (VHIT) in patients with Menière's Disease (MD). Some reported 100% normal VHIT results, others not. These discrepancies may be due to differences in severity. The present study compared VHIT and caloric reflex test results in advanced unilateral definite MD. A prospective study included 37 consecutive patients, with a mean age of 56±12 years. Mean hearing loss was 59±18dB HL; 12 patients were subject to Tumarkin's otolithic crises. Abnormal caloric reflex was defined as ≥20% deficit, and abnormal VHIT as presence of saccades or <0.64 gain in vertical semicircular canals and <0.78 in horizontal canals. All patients had normal VHIT results, and 3 had normal caloric reflex; mean caloric reflex deficit was 45%. The present study is the only one to use the August 2015 updated definition of MD. The results showed that, outside of episodes of crisis, VHIT was normal during advanced unilateral definite MD, in contrast to abnormal caloric reflex. This feature could help distinguish MD from other inner ear diseases, and it would be interesting to try to confirm this hypothesis by studying MD patients. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Role of muscle pulleys in producing eye position-dependence in the angular vestibuloocular reflex: a model-based study

NASA Technical Reports Server (NTRS)

Thurtell, M. J.; Kunin, M.; Raphan, T.; Wall, C. C. (Principal Investigator)

2000-01-01

It is well established that the head and eye velocity axes do not always align during compensatory vestibular slow phases. It has been shown that the eye velocity axis systematically tilts away from the head velocity axis in a manner that is dependent on eye-in-head position. The mechanisms responsible for producing these axis tilts are unclear. In this model-based study, we aimed to determine whether muscle pulleys could be involved in bringing about these phenomena. The model presented incorporates semicircular canals, central vestibular pathways, and an ocular motor plant with pulleys. The pulleys were modeled so that they brought about a rotation of the torque axes of the extraocular muscles that was a fraction of the angle of eye deviation from primary position. The degree to which the pulleys rotated the torque axes was altered by means of a pulley coefficient. Model input was head velocity and initial eye position data from passive and active yaw head impulses with fixation at 0 degrees, 20 degrees up and 20 degrees down, obtained from a previous experiment. The optimal pulley coefficient required to fit the data was determined by calculating the mean square error between data and model predictions of torsional eye velocity. For active head impulses, the optimal pulley coefficient varied considerably between subjects. The median optimal pulley coefficient was found to be 0.5, the pulley coefficient required for producing saccades that perfectly obey Listing's law when using a two-dimensional saccadic pulse signal. The model predicted the direction of the axis tilts observed in response to passive head impulses from 50 ms after onset. During passive head impulses, the median optimal pulley coefficient was found to be 0.21, when roll gain was fixed at 0.7. The model did not accurately predict the alignment of the eye and head velocity axes that was observed early in the response to passive head impulses. We found that this alignment could be well predicted if the roll gain of the angular vestibuloocular reflex was modified during the initial period of the response, while pulley coefficient was maintained at 0.5. Hence a roll gain modification allows stabilization of the retinal image without requiring a change in the pulley effect. Our results therefore indicate that the eye position-dependent velocity axis tilts could arise due to the effects of the pulleys and that a roll gain modification in the central vestibular structures may be responsible for countering the pulley effect.

[Video-Head impulse test with little diagnostic impact in vertigo-patients].

PubMed

Patscheke, Jochen Henrik; Plenz, Pauline; Ernst, Stephan; Klußmann, Jens-Peter

2018-03-01

Video-head impulse test (V-HIT) is more and more becoming a routine test in patients with vertigo, contributing information about the vestibulo-ocular reflex (VOR). According to Ewald's second law, the unilateral pathological test points to this side's peripheral organ as being diseased. The value in clinical routine is still unclear. 171 consecutive patients with vertigo that had received a V-HIT and caloric testing at presentation in an academic ENT-department were included. By chart-review, they were categorized in different groups with unilateral peripheral, central and other etiology of vertigo, irrespective of their V-HIT result. Then the latter was analyzed within the different groups with respect to Gain, Gain-Asymmetry (GA) and Catch-up Saccades (CS). Canal Paresis (CP) from caloric testing was compared to GA. In patients with unilateral peripheral disease, 31 % showed a pathological gain (< 0.8), the mean GA was 4.53 % (± 16.72 %) and 60 % had CSs. In patients with presumed or assured central etiology, these data were 28 %, -1,56 % (± 17,89 %) and 45 %. Isolated CS occurred only sporadically. CP was not correlated with GA in all groups (p = 0,114). In this study V-HIT showed little diagnostic use, especially in separating peripheral from central disease. The lacking correlation between asymmetry in caloric testing and asymmetry of V-HIT gain challenges current pathophysiological concepts of impaired VOR. Georg Thieme Verlag KG Stuttgart · New York.

Motor Inhibition Test: Technical Report 13. Disadvantaged Children and Their First School Experiences. ETS-Head Start Longitudinal Study. Technical Report Series.

ERIC Educational Resources Information Center

Ward, William C.

The Motor Inhibition Test, which measures "impulse control," requires the child to perform three motor acts. These acts are: walking a distance of six feet on a five-ince wide runway; drawing a line, using ruler and pencil, between two points 8-1/2 inches apart; and winding a toy jeep up to the rear of a toy two truck, a distance of 30…

Vestibular neurolabyrinthitis: a follow-up study with cervical and ocular vestibular evoked myogenic potentials and the video head impulse test.

PubMed

Magliulo, Giuseppe; Gagliardi, Silvia; Ciniglio Appiani, Mario; Iannella, Giannicola; Re, Massimo

2014-03-01

The aim of this study was to evaluate prospectively, in a group of patients affected by vestibular neurolabyrinthitis (VN), a diagnostic protocol including cervical vestibular evoked myogenic potentials (C-VEMPs), ocular vestibular evoked myogenic potentials (O-VEMPs), and the video head impulse test (vHIT). The diagnosis of VN was based on the patient's clinical history, an absence of associated auditory or neurologic symptoms, and a neuro-otological examination with an evaluation of lateral semicircular canal function by use of the Fitzgerald-Hallpike caloric vestibular test and the ice test. In our series, 55% of the cases were superior and inferior VN, 40% were superior VN, and 5% were inferior VN. These cases, however, comprised different degrees of vestibular involvement, as the individual vestibular end organs have different prognoses. Four patients had only deficits of the horizontal and superior semicircular canals or their ampullary nerves. The implementation of C-VEMPs, O-VEMPs, and the vHIT in a vestibular diagnostic protocol has made it possible to observe patients with ampullary VN in a way that has not been feasible with other types of vestibular examinations. The age of the patient seems to have some impact on recovery from VN. When recovery occurs in the utricular and saccular nerves first and in the ampullary nerves subsequently, it may be reasonable to expect a more favorable outcome.

[Vertigo and dizziness in the emergency room].

PubMed

Zwergal, A; Möhwald, K; Dieterich, M

2017-06-01

Vertigo and dizziness are among the most common chief complaints in the emergency department. Etiologies can be categorized into three subgroups: neurootological (vestibular), medical (especially cardiovascular, metabolic), and psychiatric disorders. The diagnostic approach in the emergency department is based on a systematic analysis of case history (type, time course of symptoms, modulating factors, associated symptoms), clinical examination of the vestibular, ocular motor, and cerebellar systems (head impulse test, nystagmus, skew deviation, positioning maneuver, test of gait and stance), as well as a basal monitoring (vital signs, 12-lead ECG, blood tests). For differentiation of peripheral and central etiologies in acute vestibular syndrome, the HINTS exam (head impulse test, nystagmus, test of skew) and examination of smooth pursuit and saccades should be applied. Nonselective use of neuroimaging is not indicated due to a low diagnostic yield. Cranial imaging should be done in the following constellations: (1) detection of focal neurological or central ocular motor and vestibular signs on clinical exam, (2) acute abasia with only minor ocular motor signs, (3) presence of various cardiovascular risk factors, (4) headache of unknown quality as an accompanying symptom. Besides the symptomatic therapy of vertigo and dizziness with antiemetics or analgesics, further diagnostic differentiation is urgent to guide proper treatment. Examples are the acute therapy in cerebral ischemia, the execution of positioning maneuvers in benign paroxysmal positional vertigo, the use of corticosteroids in acute unilateral vestibulopathy, as well as the readjustment of metabolic homeostasis in medical disorders.

Computerized neuropsychological test performance of youth football players at different positions: A comparison of high and low contact players.

PubMed

Tsushima, William T; Ahn, Hyeong Jun; Siu, Andrea M; Fukuyama, Tama; Murata, Nathan M

2017-02-28

The aim of this study was to examine the effects of head impact frequency on the neuropsychological test results of football players who participate in different positions on the team. Based on the biomechanical measures of head impact frequency reported in high school football, a High Contact group (n = 480) consisting of offensive and defensive linemen was compared with a Low Contact group (n = 640) comprised of receivers and defensive backs. The results revealed that the High Contact group obtained poorer performances on the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) on three Composite scores (Verbal Memory, Visual Motor Speed, Impulse Control) and the Total Symptom score compared to the Low Contact group. The present study is the first, to date, to report differences in the neuropsychological test performances of athletes who participate in high and low contact football positions. The findings raise tentative concerns that youth football players exposed to repetitive head trauma, including subconcussive impacts, may be at risk for lowered neuropsychological functioning and increased symptoms.

Compensatory Saccades Are Associated With Physical Performance in Older Adults: Data From the Baltimore Longitudinal Study of Aging.

PubMed

Xie, Yanjun; Anson, Eric R; Simonsick, Eleanor M; Studenski, Stephanie A; Agrawal, Yuri

2017-03-01

To determine whether compensatory saccade metrics observed in the video head impulse test, specifically saccade amplitude and latency, predict physical performance. Cross-sectional analysis of the Baltimore Longitudinal Study of Aging, a prospective cohort study. National Institute on Aging Intramural Research Program Clinical Research Unit in Baltimore, Maryland. Community-dwelling older adults. Video head impulse testing was performed, and compensatory saccades and horizontal vestibulo-ocular reflex (VOR) gain were measured. Physical performance was assessed using the Short Physical Performance Battery (SPPB), which included the feet side-by-side, semitandem, tandem, and single-leg stance; repeated chair stands; and usual gait speed measurements. Compensatory saccade amplitude and latency, VOR gain, and SPPB performance. In 183 participants who underwent vestibular and SPPB testing (mean age 71.8 yr; 53% females), both higher mean saccade amplitude (odds ratio [OR] =1.62, p = 0.010) and shorter mean saccade latency (OR = 0.88, p = 0.004) were associated with a higher odds of failing the tandem stand task. In contrast, VOR gain was not associated with any physical performance measure. We observed in a cohort of healthy older adults that compensatory saccade amplitude and latency were associated with tandem stance performance. Compensatory saccade metrics may provide insights into capturing the impact of vestibular loss on physical function in older adults.

The Role of Predictability in Saccadic Eye Responses in the Suppression Head Impulse Test of Horizontal Semicircular Canal Function.

PubMed

Rey-Martinez, Jorge; Yanes, Joaquin; Esteban, Jonathan; Sanz, Ricardo; Martin-Sanz, Eduardo

2017-01-01

In the suppression head impulse paradigm (SHIMP) vHIT protocol, the participant is instructed to follow with his gaze a mobile target generated by a laser placed on the participant's head. Recent studies have reported that the refixation saccade latencies are in relation with the time evolution of the vestibular dysfunction in both (standard and SHIMP) procedures. We hypothesized that some central mechanisms like head impulse prediction could be one of the causes for the differences in the saccadic eye responses. A prospective cohort non-randomized study was designed. For the SHIMP protocol, recorded with the ICS Impulse ver. 4.0 ® (Otometrics A/S, Taastrup, Denmark) vHIT device, three different algorithms were performed: "predictable," "less predictable," and "unpredictable" depending on the target's predictability. A mathematical method was developed to analyze the SHIMP responses. The method was implemented as an additional tool to the MATLAB open source script for the extended analysis of the vHIT responses named HITCal. In cohort 1, 52 participants were included in "predictable" SHIMP protocol. In cohort 2, 60 patients were included for the "less predictable" and 35 patients for the "unpredictable" SHIMP protocol. The participants made more early saccades when instructed to perform the "predictable" paradigm compared with the "less predictable" paradigm ( p  < 0.001). The less predictable protocol did not reveal any significant difference when compared with the unpredictable protocol ( p  = 0.189). For the latency of the first saccade, there was statistical difference between the "unpredictable" and "predictable" protocols ( p  < 0.001) and between the "less predictable" and "predictable" protocols ( p  < 0.001). Finally, we did not find any relationship between the horizontal vestibulo-ocular reflex (hVOR) gain and the latency of the saccades. We developed a specific method to analyze and detect early SHIMP saccades. Our findings offer evidence regarding the influence of predictability on the latency of the SHIMP saccadic responses, suggesting that early saccades are probably caused by a conditioned response of the participant. The lack of relationship between the hVOR gain and the latency of the saccades suggests that the predictive behavior that caused the early eye saccades are independent of the vestibular function.

Vestibular Restoration and Adaptation in Vestibular Neuritis and Ramsay Hunt Syndrome With Vertigo.

PubMed

Martin-Sanz, Eduardo; Rueda, Almudena; Esteban-Sanchez, Jonathan; Yanes, Joaquin; Rey-Martinez, Jorge; Sanz-Fernandez, Ricardo

2017-08-01

To evaluate vestibular restoration and the evolution of the compensatory saccades in acute severe inflammatory vestibular nerve paralysis, including vestibular neuritis and Ramsay Hunt syndrome with vertigo. Prospective. Tertiary referral center. Vestibular neuritis (n = 18) and Ramsay Hunt syndrome patients with vertigo (n = 13) were enrolled. After treatment with oral corticosteroids, patients were followed up for 6 months. Functional recovery of the facial nerve was scored according to the House-Brackman grading system. Caloric and video head impulse tests were performed in every patient at the time of enrolment. Subsequently, successive video head impulse test (vHIT) exploration was performed at the 1, 3, and 6-month follow-up. Eighteen patients with vestibular neuritis and 13 with Ramsay Hunt syndrome and associated vertigo were included. Vestibular function was significantly worse in patients with Ramsay Hunt syndrome than in those with vestibular neuritis. Similar compensatory saccades velocity and latency values were observed in both groups, in both the caloric and initial vHIT tests. Successive vHIT results showed a significantly higher vestibulo-ocular reflex gain recovery in vestibular neuritis patients than in Ramsay Hunt syndrome patients. A significantly faster reduction in the latency, velocity, and organization of the compensatory saccades was observed in neuritis than in Ramsay Hunt syndrome patients. In addition to the recovery of the vestibulo-ocular reflex, the reduction of latency, velocity and the organization of compensatory saccades play a role in vestibular compensation.

Video Head Impulse Test to Preoperatively Identify the Nerve of Origin of Vestibular Schwannomas.

PubMed

Constanzo, Felipe; Sens, Patricia; Teixeira, Bernardo Corrêa de Almeida; Ramina, Ricardo

2018-05-10

Identification of the nerve of origin in vestibular schwannoma (VS) is an important prognostic factor for hearing preservation surgery. Thus far, vestibular functional tests and magnetic resonance imaging have not yielded reliable results to preoperatively evaluate this information. The development of the video head impulse test (vHIT) has allowed a precise evaluation of each semicircular canal, and its localizing value has been tested for some peripheral vestibular diseases, but not for VS. To correlate patterns of semicircular canal alteration on vHIT to intraoperative identification of the nerve of origin of VSs. A total 31 patients with sporadic VSs were preoperatively evaluated with vHIT (gain of vestibule-ocular reflex, overt and covert saccades on each semicircular canal) and then the nerve of origin was surgically identified during surgical resection via retrosigmoid approach. vHIT results were classified as normal, isolated superior vestibular nerve (SVN) pattern, isolated inferior vestibular nerve (IVN) pattern, predominant SVN pattern, and predominant IVN pattern. Hannover classification, cystic component, and distance between the tumor and the end of the internal auditory canal were also considered for analysis. Three patients had a normal vHIT, 12 had an isolated SVN pattern, 5 had an isolated IVN pattern, 7 had a predominant SVN pattern, and 4 had a predominant IVN pattern. vHIT was able to correctly identify the nerve of origin in 89.7% of cases (100% of altered exams). The pattern of semicircular canal dysfunction on vHIT has a localizing value to identify the nerve of origin in VSs.

Importance of spontaneous nystagmus detection in the differential diagnosis of acute vertigo.

PubMed

Pavlin-Premrl, Davor; Waterston, John; McGuigan, Sean; Infeld, Bernard; Sultana, Ron; O'Sullivan, Richard; Gerraty, Richard P

2015-03-01

Vertigo is a common cause of emergency department attendance. Detection of spontaneous nystagmus may be a useful sign in distinguishing vestibular neuritis from other vestibular diagnoses. We aimed to assess the contribution of spontaneous nystagmus in the diagnosis of acute vertigo. We enrolled consecutive consenting patients arriving at a single emergency department with acute vertigo. There was no declared protocol for the emergency department staff. A standardized history and examination was conducted by the investigators. Observation for spontaneous nystagmus, its response to visual fixation, and testing the vestibulo-ocular reflex with the horizontal head impulse test were the chief examination components. MRI was obtained within 24 hours. Clinical criteria and MRI were used to reach the final diagnosis. The investigators' physical findings and final neurological diagnosis were compared with the initial emergency department examination findings and the referral diagnosis. There were 28 patients, 15 with vestibular neuritis, six with benign paroxysmal positional vertigo, one with stroke, suspected clinically, and three with migraine. In three the diagnosis remained uncertain. Spontaneous nystagmus was seen in all 15 patients with vestibular neuritis, fixation-suppressed in eight of 11 tested for this. The head impulse test was positive in 12 of 15 with vestibular neuritis. The emergency department referral diagnosis was correct in six of 23 patients. The ability to detect spontaneous nystagmus is useful in vestibular diagnosis, both in support of a diagnosis of vestibular neuritis and in avoiding false positive diagnoses of benign paroxysmal positional vertigo. Copyright © 2014 Elsevier Ltd. All rights reserved.

Unique Contributions of Impulsivity and Inhibition to Prereading Skills in Preschoolers at Head Start

ERIC Educational Resources Information Center

Fuhs, Mary Wagner; Wyant, Autumn B.; Day, Jeanne D.

2011-01-01

The goal of this study was to explore the relationship between temperament (specifically impulsivity and inhibition) and prereading skills (letter knowledge and print concepts) in preschool children from disadvantaged backgrounds. The participants in the study were 111 preschool children with a mean age of 58.09 months (SD = 5.80) attending Head…

Variability in the control of head movements in seated humans: a link with whiplash injuries?

PubMed Central

Vibert, N; MacDougall, H G; de Waele, C; Gilchrist, D P D; Burgess, A M; Sidis, A; Migliaccio, A; Curthoys, I S; Vidal, P P

2001-01-01

The aim of this study was to determine how context and on-line sensory information are combined to control posture in seated subjects submitted to high-jerk, passive linear accelerations. Subjects were seated with eyes closed on a servo-controlled linear sled. They were asked to relax and received brief accelerations either sideways or in the fore-aft direction. The stimuli had an abrupt onset, comparable to the jerk experienced during a minor car collision. Rotation and translation of the head and body were measured using an Optotrak system. In some of the subjects, surface electromyographic (EMG) responses of selected neck and/or back muscles were recorded simultaneously. For each subject, responses were highly stereotyped from the first trial, and showed little sign of habituation or sensitisation. Comparable results were obtained with sideways and fore-aft accelerations. During each impulse, the head lagged behind the trunk for several tens of milliseconds. The subjects' head movement responses were distributed as a continuum in between two extreme categories. The ‘stiff’ subjects showed little rotation or translation of the head relative to the trunk for the whole duration of the impulse. In contrast, the ‘floppy’ subjects showed a large roll or pitch of the head relative to the trunk in the direction opposite to the sled movement. This response appeared as an exaggerated ‘inertial’ response to the impulse. Surface EMG recordings showed that most of the stiff subjects were not contracting their superficial neck or back muscles. We think they relied on bilateral contractions of their deep, axial musculature to keep the head-neck ensemble in line with the trunk during the movement. About half of the floppy subjects displayed reflex activation of the neck muscles on the side opposite to the direction of acceleration, which occurred before or during the head movement and tended to exaggerate it. The other floppy subjects seemed to rely on only the passive biomechanical properties of their head-neck ensemble to compensate for the perturbation. In our study, proprioception was the sole source of sensory information as long as the head did not move. We therefore presume that the EMG responses and head movements we observed were mainly triggered by the activation of stretch receptors in the hips, trunk and/or neck. The visualisation of an imaginary reference in space during sideways impulses significantly reduced the head roll exhibited by floppy subjects. This suggests that the adoption by the central nervous system of an extrinsic, ‘allocentric’ frame of reference instead of an intrinsic, ‘egocentric’ one may be instrumental for the selection of the stiff strategy. The response of floppy subjects appeared to be maladaptive and likely to increase the risk of whiplash injury during motor vehicle accidents. Evolution of postural control may not have taken into account the implications of passive, high-acceleration perturbations affecting seated subjects. PMID:11313451

Effect of cervicolabyrinthine impulsation on the spinal reflex apparatus

NASA Technical Reports Server (NTRS)

Yarotskiy, A. I.

1980-01-01

In view of the fact that the convergence effect of vestibular impulsation may both stimulate and inhibit intra and intersystemic coordination of physiological processes, an attempt was made to define the physiological effect on the spinal reflex apparatus of the convergence of cervicolabyrinthine impulsation on a model of the unconditioned motor reflex as a mechanism of the common final pathway conditioning the formation and realization of a focused beneficial result of human motor activities. More than 100 persons subjected to rolling effect and angular acceleration during complexly coordinated muscular loading were divided according to typical variants of the functional structure of the patella reflex in an experiment requiring 30 rapid counterclockwise head revolutions at 2/sec with synchronous recording of a 20 item series of patella reflex acts. A knee jerk coefficient was used in calculations. In 85 percent of the cases 2 patellar reflexograms show typical braking and release of knee reflex and 1 shows an extreme local variant. The diagnostic and prognostic value of these tests is suggested for determining adaptive possibilities of functional systems in respect to acceleration and proprioceptive stimuli.

Preference for Progressive Delays and Concurrent Physical Therapy Exercise in an Adult with Acquired Brain Injury

ERIC Educational Resources Information Center

Dixon, Mark R.; Falcomata, Terry S.

2004-01-01

The purpose of this study was to increase self-control and engagement in a physical therapy task (head holding) for a man with acquired traumatic brain injury. Once impulsivity was observed (i.e., repeated impulsive choices), an experimental condition was introduced that consisted of choices between a small immediate reinforcer, a large…

Nucleus prepositus hypoglossi lesions produce a unique ocular motor syndrome

PubMed Central

Kim, Sung-Hee; Zee, David S.; du Lac, Sascha; Kim, Hyo Jung

2016-01-01

Objective: To describe the ocular motor abnormalities in 9 patients with a lesion involving the nucleus prepositus hypoglossi (NPH), a key constituent of a vestibular-cerebellar-brainstem neural network that ensures that the eyes are held steady in all positions of gaze. Methods: We recorded eye movements, including the vestibulo-ocular reflex during head impulses, in patients with vertigo and a lesion involving the NPH. Results: Our patients showed an ipsilesional-beating spontaneous nystagmus, horizontal gaze-evoked nystagmus more intense on looking toward the ipsilesional side, impaired pursuit more to the ipsilesional side, central patterns of head-shaking nystagmus, contralateral eye deviation, and decreased vestibulo-ocular reflex gain during contralesionally directed head impulses. Conclusions: We attribute these findings to an imbalance in the NPH–inferior olive–flocculus–vestibular nucleus loop, and the ocular motor abnormalities provide a new brainstem localization for patients with acute vertigo. PMID:27733568

Effects of humoral factors on ventilation kinetics during recovery after impulse-like exercise.

PubMed

Afroundeh, R; Arimitsu, T; Yamanaka, R; Lian, C; Yunoki, T; Yano, Tokuo

2012-06-01

To clarify the ventilatory kinetics during recovery after impulse-like exercise, subjects performed one impulse-like exercise test (one-impulse) and a five-times repeated impulse-like exercises test (five-impulse). Duration and intensity of the impulse-like exercise were 20 sec and 400 watts (80 rpm), respectively. Although blood pH during recovery (until 10 min) was significantly lower in the five-impulse test than in the one-impulse test, ventilation (.VE) in the two tests was similar except during the first 30 sec of recovery, in which it was higher in the five-impulse test. In one-impulse, blood CO2 pressure (PCO2) was significantly increased at 1 min during recovery and then returned to the pre-exercise level at 5 min during recovery. In the five-impulse test, PCO2 at 1 min during recovery was similar to the pre-exercise level, and then it decreased to a level lower than the pre-exercise level at 5 min during recovery. Accordingly, PCO2 during recovery (until 30 min) was significantly lower in the five-impulse than in one-impulse test..VE and pH during recovery showed a curvilinear relationship, and at the same pH, ventilation was higher in the one-impulse test. These results suggest that ventilatory kinetics during recovery after impulse-like exercise is attributed partly to pH, but the stimulatory effect of lower pH is diminished by the inhibitory effect of lower PCO2.

Role of helmet in the mechanics of shock wave propagation under blast loading conditions.

PubMed

Ganpule, S; Gu, L; Alai, A; Chandra, N

2012-01-01

The effectiveness of helmets in extenuating the primary shock waves generated by the explosions of improvised explosive devices is not clearly understood. In this work, the role of helmet on the overpressurisation and impulse experienced by the head were examined. The shock wave-head interactions were studied under three different cases: (i) unprotected head, (ii) head with helmet but with varying head-helmet gaps and (iii) head covered with helmet and tightly fitting foam pads. The intensification effect was discussed by examining the shock wave flow pattern and verified with experiments. A helmet with a better protection against shock wave is suggested.

The Spectrum of Sociopathy in Dementia

PubMed Central

Mendez, Mario F.; Shapira, Jill S.; Saul, Ronald E.

2012-01-01

Although well-known from head trauma and acute strokes, sociopathic behavior from dementia is less known and understood. This study reviewed 33 dementia patients who had been in trouble with the law. They were divided into two groups: 22 who committed impulsive sociopathic acts and 11 who committed non-impulsive acts. The impulsive patients demonstrated nonviolent acts, such as dis-inhibited sexual behavior or pathological stealing, and had disproportionate frontal-caudate atrophy on neuroimaging. The majority of non-impulsive patients demonstrated agitation-paranoia, sometimes with reactive aggression, delusional beliefs, or aphasic paranoia, and had advanced memory and other cognitive impairment. The impulsive patients tended to have frontally predominant illnesses such as frontotemporal dementia or Huntington’s disease, whereas the non-impulsive group tended to have Alzheimer’s disease or prominent aphasia. Sociopathy has different causes in dementia. Two common mechanisms are disinhibition, with frontally predominant disease, and agitation-paranoia, with greater cognitive impairment. These forms of sociopathy differ significantly from the antisocial/ psychopathic personality. PMID:21677240

Impulsive force on the head during performance of typical ukemi techniques following different judo throws.

PubMed

Hashimoto, Toshihiko; Ishii, Takanori; Okada, Naoyuki; Itoh, Masahiro

2015-01-01

In this study, eight judo athletes who are major candidates for the Japan national team were recruited as participants. Kinematic analysis of exemplary ukemi techniques was carried out using two throws, o-soto-gari, a throw linked to frequent injury, and o-uchi-gari. The aim of this study was to kinematically quantify the timing patterns of exemplary ukemi techniques and to obtain kinematic information of the head, in a sequence of ukemi from the onset of the throw to the completion of ukemi. The results indicated that the vertical velocity with which the uke's head decelerated was reduced by increasing the body surface exposed to the collision with the tatami and by increasing the elapsed time. In particular, overall upper limb contact with the tatami is greatly associated with deceleration. In o-soto-gari, the impulsive force on the faller's head as the head reached the lowest point was 204.82 ± 19.95 kg m · s(-2) while in o-uchi-gari it was 118.46 ± 63.62 kg m · s(-2), z = -1.75, P = 0.08, and it did present a large-sized effect with r = 0.78. These findings indicate that the exemplary o-soto-gari as compared to o-uchi-gari is the technique that causes more significant damage to the uke's head.

Murder or Not? Cold Temperature Makes Criminals Appear to Be Cold-Blooded and Warm Temperature to Be Hot-Headed

PubMed Central

Gockel, Christine; Kolb, Peter M.; Werth, Lioba

2014-01-01

Temperature-related words such as cold-blooded and hot-headed can be used to describe criminal behavior. Words associated with coldness describe premeditated behavior and words associated with heat describe impulsive behavior. Building on recent research about the close interplay between physical and interpersonal coldness and warmth, we examined in a lab experiment how ambient temperature within a comfort zone influences judgments of criminals. Participants in rooms with low temperature regarded criminals to be more cold-blooded than participants in rooms with high temperature. Specifically, they were more likely to attribute premeditated crimes, ascribed crimes resulting in higher degrees of penalty, and attributed more murders to criminals. Likewise, participants in rooms with high temperature regarded criminals to be more hot-headed than participants in rooms with low temperature: They were more likely to attribute impulsive crimes. Results imply that cognitive representations of temperature are closely related to representations of criminal behavior and attributions of intent. PMID:24788725

Murder or not? Cold temperature makes criminals appear to be cold-blooded and warm temperature to be hot-headed.

PubMed

Gockel, Christine; Kolb, Peter M; Werth, Lioba

2014-01-01

Temperature-related words such as cold-blooded and hot-headed can be used to describe criminal behavior. Words associated with coldness describe premeditated behavior and words associated with heat describe impulsive behavior. Building on recent research about the close interplay between physical and interpersonal coldness and warmth, we examined in a lab experiment how ambient temperature within a comfort zone influences judgments of criminals. Participants in rooms with low temperature regarded criminals to be more cold-blooded than participants in rooms with high temperature. Specifically, they were more likely to attribute premeditated crimes, ascribed crimes resulting in higher degrees of penalty, and attributed more murders to criminals. Likewise, participants in rooms with high temperature regarded criminals to be more hot-headed than participants in rooms with low temperature: They were more likely to attribute impulsive crimes. Results imply that cognitive representations of temperature are closely related to representations of criminal behavior and attributions of intent.

Hearing Protection Evaluation for the Combat Arms Earplug at Idaho National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

James Lovejoy

2007-03-01

The Idaho National Laboratory (INL) is managed by Battelle Energy Alliance, LLC (BEA) for the Department of Energy. The INL Protective Security Forces (Pro Force) are involved in training exercises that generate impulse noise by small arms fire. Force-on-force (FOF) training exercises that simulate real world scenarios require the Pro Force to engage the opposition force (OPFOR) while maintaining situational awareness through verbal communications. The Combat Arms earplug was studied to determine if it provides adequate hearing protection in accordance with the requirements of MIL-STD-1474C/D. The Combat Arms earplug uses a design that allows continuous noise through a critical orificemore » while effectively attenuating high-energy impulse noise. The earplug attenuates noise on a non linear scale, as the sound increases the attenuation increases. The INL studied the effectiveness of the Combat Arms earplug with a Bruel & Kjaer (B&K) head and torso simulator used with a selection of small arms to create impulse sound pressures. The Combat Arms earplugs were inserted into the B&K head and torso ears, and small arms were then discharged to generate the impulse noise. The INL analysis of the data indicates that the Combat Arms earplug does provide adequate protection, in accordance with MIL-STD-1474C/D, when used to protect against impulse noise generated by small arms fire using blank ammunition. Impulse noise generated by small arms fire ranged from 135–160 dB range unfiltered un-weighted. The Combat Arms earplug attenuated the sound pressure 10–25 dB depending on the impulse noise pressure. This assessment is consistent with the results of previously published studies on the Combat Arms earplug (see Section 5, “References”). Based upon these result, the INL intends to use the Combat Arms earplug for FOF training exercises.« less

Can emergency physicians accurately and reliably assess acute vertigo in the emergency department?

PubMed

Vanni, Simone; Nazerian, Peiman; Casati, Carlotta; Moroni, Federico; Risso, Michele; Ottaviani, Maddalena; Pecci, Rudi; Pepe, Giuseppe; Vannucchi, Paolo; Grifoni, Stefano

2015-04-01

To validate a clinical diagnostic tool, used by emergency physicians (EPs), to diagnose the central cause of patients presenting with vertigo, and to determine interrater reliability of this tool. A convenience sample of adult patients presenting to a single academic ED with isolated vertigo (i.e. vertigo without other neurological deficits) was prospectively evaluated with STANDING (SponTAneousNystagmus, Direction, head Impulse test, standiNG) by five trained EPs. The first step focused on the presence of spontaneous nystagmus, the second on the direction of nystagmus, the third on head impulse test and the fourth on gait. The local standard practice, senior audiologist evaluation corroborated by neuroimaging when deemed appropriate, was considered the reference standard. Sensitivity and specificity of STANDING were calculated. On the first 30 patients, inter-observer agreement among EPs was also assessed. Five EPs with limited experience in nystagmus assessment volunteered to participate in the present study enrolling 98 patients. Their average evaluation time was 9.9 ± 2.8 min (range 6-17). Central acute vertigo was suspected in 16 (16.3%) patients. There were 13 true positives, three false positives, 81 true negatives and one false negative, with a high sensitivity (92.9%, 95% CI 70-100%) and specificity (96.4%, 95% CI 93-38%) for central acute vertigo according to senior audiologist evaluation. The Cohen's kappas of the first, second, third and fourth steps of the STANDING were 0.86, 0.93, 0.73 and 0.78, respectively. The whole test showed a good inter-observer agreement (k = 0.76, 95% CI 0.45-1). In the hands of EPs, STANDING showed a good inter-observer agreement and accuracy validated against the local standard of care. © 2015 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Vestibular evoked myogenic potentials and video head impulse test in patients with vertigo, dizziness and imbalance.

PubMed

Skorić, Magdalena Krbot; Adamec, Ivan; Pavičić, Tin; Pavlović, Ivan; Ruška, Berislav; Crnošija, Luka; Habek, Mario

2017-05-01

The aim of this study was to compare vestibular evoked myogenic potentials (VEMP) and video head impulse test (vHIT) results in patients presenting with vertigo and dizziness. We retrospectively analyzed data of all patients with the chief complaint of vertigo, dizziness, or imbalance that underwent VEMP and vHIT from January 2015 to January 2016. A total of 117 patients (73 females, mean age 53.92±16.76) fulfilled inclusion criteria: group 1 included patients with the final diagnosis of vestibular neuritis (VN) (N=31 (16 right and 15 left VN)), group 2 included patients with the final diagnosis of vertigo of central origin (N=23) and group 3 included patients with the final diagnosis of unspecified dizziness (N=63). There was significant correlation between oVEMP asymmetry and asymmetry of the lateral canals 60ms gains on vHIT (r=0.225, p=0.026). Significant correlation between oVEMP and vHIT asymmetry was present in VN patients (r=0.749, p<0.001), while no correlation was found in the groups 2 and 3. oVEMP and vHIT lateral canals asymmetries were significantly greater in patients with vestibular neuritis. Furthermore, positive correlations of oVEMP amplitudes with 60ms gain of the lateral semicircular canal and slope of the anterior semicircular canal on vHIT, and cVEMP with slope of the posterior semicircular canal on the vHIT were found. These changes were significantly more pronounced in patients with vestibular neuritis. In conclusion, VEMPs and vHIT data should be used complementarily; asymmetry on both tests strongly supports peripheral vestibular system involvement. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neurofeedback training with virtual reality for inattention and impulsiveness.

PubMed

Cho, Baek-Hwan; Kim, Saebyul; Shin, Dong Ik; Lee, Jang Han; Lee, Sang Min; Kim, In Young; Kim, Sun I

2004-10-01

In this research, the effectiveness of neurofeedback, along with virtual reality (VR), in reducing the level of inattention and impulsiveness was investigated. Twenty-eight male participants, aged 14-18, with social problems, took part in this study. They were separated into three groups: a control group, a VR group, and a non-VR group. The VR and non-VR groups underwent eight sessions of neurofeedback training over 2 weeks, while the control group just waited during the same period. The VR group used a head-mounted display (HMD) and a head tracker, which let them look around the virtual world. Conversely, the non-VR group used only a computer monitor with a fixed viewpoint. All participants performed a continuous performance task (CPT) before and after the complete training session. The results showed that both the VR and non-VR groups achieved better scores in the CPT after the training session, while the control group showed no significant difference. Compared with the other groups, the VR group presented a tendency to get better results, suggesting that immersive VR is applicable to neurofeedback for the rehabilitation of inattention and impulsiveness.

Comparative Assessment of Torso and Seat Mounted Restraint Systems using Manikins on the Horizontal Impulse Accelerator

DTIC Science & Technology

2017-11-01

rearward rotation of the head towards the back or shoulder blades ). The y- axis of the head runs from right ear canal to the left ear canal with...PERSON (Monitor) a. REPORT Unclassified b. ABSTRACT Unclassified c . THIS PAGE Unclassified Chris Burneka 19b. TELEPHONE NUMBER...92 APPENDIX C . SAMPLE DATA SHEETS

Pathological gambling: an impulse control disorder? Measurement of impulsivity using neurocognitive tests.

PubMed

Dannon, Pinhas N; Shoenfeld, Netta; Rosenberg, Oded; Kertzman, Semion; Kotler, Moshe

2010-04-01

Pathological gambling is classified in the DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders) and in the ICD-10 (International Classification of Disease) as an impulse control disorder. The association between impulsivity and pathological gambling remains a matter of debate: some researchers find high levels of impulsivity within pathological gamblers, others report no difference compared to controls, and yet others even suggest that it is lower. In this review we examine the relationship between pathological gambling and impulsivity assessed by various neurocognitive tests. These tests--the Stroop task, the Stop Signal Task, the Matching Familiar Figures Task, the Iowa Gambling Task, the Wisconsin Card Sorting Test, the Tower of London test, and the Continuous Performance Test--demonstrated less impulsivity in gambling behavior. The differences in performance between pathological gamblers and healthy controls on the neurocognitive tasks could be due to addictive behavior features rather than impulsive behavior.

The effect of binocular eye position and head rotation plane on the human torsional vestibuloocular reflex.

PubMed

Migliaccio, Americo A; Della Santina, Charles C; Carey, John P; Minor, Lloyd B; Zee, David S

2006-08-01

We examined how the gain of the torsional vestibulo-ocular reflex (VOR) (defined as the instantaneous eye velocity divided by inverted head velocity) in normal humans is affected by eye position, target distance, and the plane of head rotation. In six normal subjects we measured three-dimensional (3D) eye and head rotation axes using scleral search coils, and 6D head position using a magnetic angular and linear position measurement device, during low-amplitude (approximately 20 degrees ), high-velocity (approximately 200 degrees/s), high-acceleration (approximately 4000 degrees /s2) rapid head rotations or 'impulses.' Head impulses were imposed manually and delivered in five planes: yaw (horizontal canal plane), pitch, roll, left anterior-right posterior canal plane (LARP), and right anterior-left posterior canal plane (RALP). Subjects were instructed to fix on one of six targets at eye level. Targets were either straight-ahead, 20 degrees left or 20 degrees right from midline, at distance 15 or 124 cm from the subject. Two subjects also looked at more eccentric targets, 30 degrees left or 30 degrees right from midline. We found that the vertical and horizontal VOR gains increased with the proximity of the target to the subject. Previous studies suggest that the torsional VOR gain should decrease with target proximity. We found, however, that the torsional VOR gain did not change for all planes of head rotation and for both target distances. We also found a dynamic misalignment of the vertical positions of the eyes during the torsional VOR, which was greatest during near viewing with symmetric convergence. This dynamic vertical skew during the torsional VOR arises, in part, because when the eyes are converged, the optical axes are not parallel to the naso-occipital axes around which the eyes are rotating. In five of six subjects, the average skew ranged 0.9 degrees -2.9 degrees and was reduced to <0.4 degrees by a 'torsional' quick-phase (around the naso-occipital axis) occurring <110 ms after the onset of the impulse. We propose that the torsional quick-phase mechanism during the torsional VOR could serve at least three functions: (1) resetting the retinal meridians closer to their usual orientation in the head, (2) correcting for the 'skew' deviation created by misalignment between the axes around which the eyes are rotating and the line of sight, and (3) taking the eyes back toward Listing's plane.

Hyperactivity persists in male and female adults with ADHD and remains a highly discriminative feature of the disorder: a case-control study

PubMed Central

2012-01-01

Background Symptoms of hyperactivity are believed to fade with age leaving ADHD adults mostly inattentive and impulsive. Our aim was to test this assertion using objective measures of hyperactivity, impulsivity and inattention. Method Participants were 40 subjects with ADHD (23M/17F; 35±10 yrs) and 60 healthy adults (28M/32F; 29±9 yrs) blindly assessed using Wender-Reimherr interview ratings, Structured Clinical Interview for DSM-IV Disorders and DSM-IV criteria. Infrared motion capture systems tracked head and leg movements during performance of a No-4’s cognitive control task. Subjects also completed the Conners’ CPT-II. Results ADHD and controls differed significantly in activity and attention. Effect sizes for activity measures (d’ = 0.7–1.6) were, on average, two-fold larger than differences in attention or impulsivity, correlated more strongly with executive function ratings and were more discriminatory (ROC area = 0.83 for activity composite, 0.65 for No-4’s distraction composite, 0.63 for Conners’ CPT-II confidence index, 0.96 for the combined activity and attention diagnostic index). This finding was true for subjects with the predominantly inattentive subtype as well as subjects with combined or predominantly hyperactive/impulsive subtype. Males and females with ADHD were equally active. The superior accuracy of activity measures was confirmed using Random Forest and predictive modeling techniques. Conclusions Objectively measured hyperactivity persists in adults with ADHD and is a more discriminative feature of the disorder than computerized measures of inattention or impulsivity. This finding supports the hypothesis that a deficient ability to sit still remains a defining feature of the disorder in adults when it is measured objectively. PMID:23134619

Antenatal betamethasone and fetal growth in prematurely born children: implications for temperament traits at the age of 2 years.

PubMed

Pesonen, Anu-Katriina; Räikkönen, Katri; Lano, Aulikki; Peltoniemi, Outi; Hallman, Mikko; Kari, M Anneli

2009-01-01

We explored whether repeated dose of antenatal betamethasone and variation in intrauterine growth of prematurely born children predict temperament characteristics at the age of 2 years. The patients (n = 142) were prematurely born children (mean gestational age: 31.0 weeks; range: 24.6-35.0 weeks) who participated in a randomized and blinded trial testing the effects of a repeated dose of antenatal betamethasone in imminent preterm birth. Fetal growth was estimated as weight, length, and head circumference in SDs according to Finnish growth charts. Parents assessed their toddlers' temperament with 201 items of the Early Childhood Temperament Questionnaire (mean child corrected age: 2.1 years). No significant main effects of repeated betamethasone on toddler temperament existed. However, a significant interaction between study group and duration of exposure to betamethasone emerged; those exposed to a repeated dose for >24 hours before delivery were more impulsive. One-SD increases in weight, length, and head circumference at birth were associated with 0.14- to 0.19-SD lower levels of negative affectivity (fearfulness, anger proneness, and sadness); 1-SD increases in length, weight, and head circumference at birth were associated with 0.14- to 0.18-SD higher levels of effortful control (self-regulation). Repeated antenatal betamethasone did not induce alterations in toddler temperament. The results, however, suggest that a longer duration of exposure is associated with higher impulsivity scores. Regardless of betamethasone exposure, slower fetal growth exerted influences on temperament. Our findings indicate prenatal programming of psychological development and imply that more attention is needed to support the development of infants born at the lower end of the fetal growth distribution.

Effects of Device on Video Head Impulse Test (vHIT) Gain.

PubMed

Janky, Kristen L; Patterson, Jessie N; Shepard, Neil T; Thomas, Megan L A; Honaker, Julie A

2017-10-01

Numerous video head impulse test (vHIT) devices are available commercially; however, gain is not calculated uniformly. An evaluation of these devices/algorithms in healthy controls and patients with vestibular loss is necessary for comparing and synthesizing work that utilizes different devices and gain calculations. Using three commercially available vHIT devices/algorithms, the purpose of the present study was to compare: (1) horizontal canal vHIT gain among devices/algorithms in normal control subjects; (2) the effects of age on vHIT gain for each device/algorithm in normal control subjects; and (3) the clinical performance of horizontal canal vHIT gain between devices/algorithms for differentiating normal versus abnormal vestibular function. Prospective. Sixty-one normal control adult subjects (range 20-78) and eleven adults with unilateral or bilateral vestibular loss (range 32-79). vHIT was administered using three different devices/algorithms, randomized in order, for each subject on the same day: (1) Impulse (Otometrics, Schaumberg, IL; monocular eye recording, right eye only; using area under the curve gain), (2) EyeSeeCam (Interacoustics, Denmark; monocular eye recording, left eye only; using instantaneous gain), and (3) VisualEyes (MicroMedical, Chatham, IL, binocular eye recording; using position gain). There was a significant mean difference in vHIT gain among devices/algorithms for both the normal control and vestibular loss groups. vHIT gain was significantly larger in the ipsilateral direction of the eye used to measure gain; however, in spite of the significant mean differences in vHIT gain among devices/algorithms and the significant directional bias, classification of "normal" versus "abnormal" gain is consistent across all compared devices/algorithms, with the exception of instantaneous gain at 40 msec. There was not an effect of age on vHIT gain up to 78 years regardless of the device/algorithm. These findings support that vHIT gain is significantly different between devices/algorithms, suggesting that care should be taken when making direct comparisons of absolute gain values between devices/algorithms. American Academy of Audiology

Effects of repetitive subconcussive head trauma on the neuropsychological test performance of high school athletes: A comparison of high, moderate, and low contact sports.

PubMed

Tsushima, William T; Ahn, Hyeong Jun; Siu, Andrea M; Yoshinaga, Kara; Choi, So Yung; Murata, Nathan M

2018-02-02

The aim of this study was to examine the neuropsychological test results of non-concussed high school athletes playing at three different levels of contact sports. Based on the concussion risk data of 12 different sports, a High Contact group (n=2819; wrestling/martial arts, cheerleading, track and field, football), a Moderate Contact group (n=2323; softball, basketball, soccer), and a Low Contact group (n=1580; baseball, volleyball, water polo, tennis, cross-country) were formed and compared in terms of their scores on the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT). The results revealed that the High Contact group obtained small but statistically poorer performances in ImPACT Visual Memory, Visual Motor Speed, Impulse Control, and Total Symptom scores compared to the Moderate and Low Contact groups. The High Contact group also had poorer Reaction Time scores compared to the Low Contact group. No differences between the Moderate and Low Contact groups were noted. The findings, along with prior similar results, tentatively raise concerns that participant in high contact sports, exposed to repetitive subconcussive head trauma, may be at greater risk for lowered neuropsychological functioning and increased symptoms, compared to other high school athletes. In view of the preliminary nature of this investigation, more research into the effects of frequent head impacts in high school sports is strongly recommended.

Performance Evaluation of Pressure Transducers for Water Impacts

NASA Technical Reports Server (NTRS)

Vassilakos, Gregory J.; Stegall, David E.; Treadway, Sean

2012-01-01

The Orion Multi-Purpose Crew Vehicle is being designed for water landings. In order to benchmark the ability of engineering tools to predict water landing loads, test programs are underway for scale model and full-scale water impacts. These test programs are predicated on the reliable measurement of impact pressure histories. Tests have been performed with a variety of pressure transducers from various manufacturers. Both piezoelectric and piezoresistive devices have been tested. Effects such as thermal shock, pinching of the transducer head, and flushness of the transducer mounting have been studied. Data acquisition issues such as sampling rate and anti-aliasing filtering also have been studied. The response of pressure transducers have been compared side-by-side on an impulse test rig and on a 20-inch diameter hemisphere dropped into a pool of water. The results have identified a range of viable configurations for pressure measurement dependent on the objectives of the test program.

The effects of padded surfaces on the risk for cervical spine injury.

PubMed

Nightingale, R W; Richardson, W J; Myers, B S

1997-10-15

This is an in vitro study comparing cervical spine injuries produced in rigid head impacts and in padded head impacts. To test the hypothesis that deformable impact surfaces pose a greater risk for cervical spine injury than rigid surfaces using a cadaver-based model that includes the effects of the head and torso masses. It is widely assumed that energy-absorbing devices that protect the head from injury also reduce the risk for neck injury. However, this has not been demonstrated in any experimental or epidemiologic study. On the contrary, some studies have shown that padded surfaces have no effect on neck injury risk, and others have suggested that they can increase risk. Experiments were performed on 18 cadaveric cervical spines to test 6 combinations of impact angle and impact surface padding. The impact surface was oriented at -15 degrees (posterior impact), 0 degree (vertex impact), or +15 degrees (anterior impact). The impact surface was either a 3-mm sheet of lubricated Teflon or 5 cm of polyurethane foam. Impacts onto padded surfaces produced significantly larger neck impulses (P = 0.00023) and a significantly greater frequency of cervical spine injuries than rigid impacts (P = 0.0375). The impact angle was also correlated with injury risk (P < 0.00001). These experiments suggest that highly deformable, padded contact surfaces should be used carefully in environments where there is the risk for cervical spine injury. The results also suggest that the orientation of the head, neck, and torso relative to the impact surface is of equal if not greater importance in neck injury risk.

Impulsivity in borderline personality disorder: a matter of disturbed impulse control or a facet of emotional dysregulation?

PubMed

Sebastian, Alexandra; Jacob, Gitta; Lieb, Klaus; Tüscher, Oliver

2013-02-01

Impulsivity is regarded as a clinical, diagnostic and pathophysiological hallmark of borderline personality disorder (BPD). Self-report measures of impulsivity consistently support the notion of higher impulsive traits in BPD patients as compared to healthy control subjects. Laboratory tests of impulsivity, i.e. neuropsychological tests of impulse control render weak and inconsistent results both across different cognitive components of impulse control and within the same cognitive component of impulse control. One important factor worsening impulsive behaviors and impulse control deficits in BPD is comorbid attention-deficit/hyperactivity disorder (ADHD). In addition, emotional dysregulation interacts with impulse control especially for BPD salient emotions. In sum, although basic mechanisms of impulse control seem not to be disturbed in BPD, clinically well observed impulsive behaviors may be explained by comorbid ADHD or may be the consequence of dysregulation of BPD salient emotions.

The Contribution of Head Movement to the Externalization and Internalization of Sounds

PubMed Central

Brimijoin, W. Owen; Boyd, Alan W.; Akeroyd, Michael A.

2013-01-01

Background When stimuli are presented over headphones, they are typically perceived as internalized; i.e., they appear to emanate from inside the head. Sounds presented in the free-field tend to be externalized, i.e., perceived to be emanating from a source in the world. This phenomenon is frequently attributed to reverberation and to the spectral characteristics of the sounds: those sounds whose spectrum and reverberation matches that of free-field signals arriving at the ear canal tend to be more frequently externalized. Another factor, however, is that the virtual location of signals presented over headphones moves in perfect concert with any movements of the head, whereas the location of free-field signals moves in opposition to head movements. The effects of head movement have not been systematically disentangled from reverberation and/or spectral cues, so we measured the degree to which movements contribute to externalization. Methodology/Principal Findings We performed two experiments: 1) Using motion tracking and free-field loudspeaker presentation, we presented signals that moved in their spatial location to match listeners’ head movements. 2) Using motion tracking and binaural room impulse responses, we presented filtered signals over headphones that appeared to remain static relative to the world. The results from experiment 1 showed that free-field signals from the front that move with the head are less likely to be externalized (23%) than those that remain fixed (63%). Experiment 2 showed that virtual signals whose position was fixed relative to the world are more likely to be externalized (65%) than those fixed relative to the head (20%), regardless of the fidelity of the individual impulse responses. Conclusions/Significance Head movements play a significant role in the externalization of sound sources. These findings imply tight integration between binaural cues and self motion cues and underscore the importance of self motion for spatial auditory perception. PMID:24312677

Head injury as a PTSD predictor among Oklahoma City bombing survivors.

PubMed

Walilko, Timothy; North, Carol; Young, Lee Ann; Lux, Warren E; Warden, Deborah L; Jaffee, Michael S; Moore, David F

2009-12-01

The aim of the Oklahoma City (OKC) bombing retrospective review was to investigate the relationship between physical injury, environmental contributors, and psychiatric disorders such as posttraumatic stress disorder (PTSD) in an event-based, matched design study focused on injury. The 182 selected participants were a random subset of the 1,092 direct survivors from the OKC bombing. Only 124 of these 182 cases had a full complement of medical/clinical data in the OKC database. These 124 cases were assessed to explore relationships among PTSD diagnoses, levels of blast exposure, and physical injuries. Associations among variables were statistically tested using contingency analysis and logistic regression. Comparison of the PTSD cases to symptoms/diagnoses reported in the medical records reveals a statistically significant association between PTSD and head/brain injuries associated with head acceleration. PTSD was not highly correlated with other injuries. Although blast pressure and impulse were highly correlated with head injuries, the correlation with PTSD was not statistically significant. Thus, a correlation between blast pressure and PTSD may exist, but higher fidelity pressure calculations are required to elucidate this potential relationship. This study provides clear evidence that head injury is associated with subsequent PTSD, giving caregivers' information on what physical injuries may suggest the development of psychologic disorders to aid them in developing a profile for the identification of future survivors of terrorist attacks and Warfighters with brain injuries and potential PTSD.

Leg stiffness and expertise in men jumping.

PubMed

Laffaye, Guillaume; Bardy, Benoît G; Durey, Alain

2005-04-01

The aim of the present study is to investigate: a) the leg spring behavior in the one-leg vertical jump, b) the contribution of impulse parameters to this behavior, and c) the effect of jumping expertise on leg stiffness. Four categories of experts (handball, basketball, volleyball players, and Fosbury athletes), as well as novice subjects performed a run-and-jump test to touch a ball with the head. Five experimental conditions were tested from 55 to 95% of the maximum jump height. Kinematic and kinetic data were collected using six cameras and a force plate. The mechanical behavior of the musculoskeleton component of the human body can be modeled as a simple mass-spring system, from which leg stiffness values can be extracted to better understand energy transfer during running or jumping. The results indicate that leg stiffness (mean value of 11.5 kN.m) decreased with jumping height. Leg shortening at takeoff also increased with jumping height, whereas contact time decreased (-18%). No difference was found between experts and novices for leg stiffness. However, a principal components analysis (PCA) indicated the contribution of two main factors to the performance. The first factor emerged out of vertical force, stiffness, and duration of impulse. The second factor included leg shortening and jumping height. Differences between experts and novices were observed in terms of the contribution of leg stiffness to jump height, and more importantly, clear differences existed between experts in jumping parameters. The analysis performed on the sport categories indeed revealed different jumping profiles, characterized by specific, sport-related impulse parameters.

Evaluation of Stiffness of the Spastic Lower Extremity Muscles in Early Spinal Cord Injury by Acoustic Radiation Force Impulse Imaging

PubMed Central

Cho, Kang Hee

2015-01-01

Objective To investigate intrinsic viscoelastic changes using shear wave velocities (SWVs) of spastic lower extremity muscles in patients with early spinal cord injury (SCI) via acoustic radiation force impulse (ARFI) imaging and to evaluate correlation between the SWV values and spasticity. Methods Eighteen patients with SCI within 3 months and 10 healthy adults participated. We applied the ARFI technique to measure SWV of gastrocnemius muscle (GCM) and long head of biceps femoris muscle. Spasticity of ankle and knee joint was assessed by original Ashworth Scale. Results Ten patients with SCI had spasticity. Patients with spasticity had significantly faster SWV for GCM and biceps femoris muscle than those without spasticity (Mann-Whitney U test, p=0.007 and p=0.008) and normal control (p=0.011 and p=0.037, respectively). The SWV values of GCM correlated with the ankle spasticity (Spearman rank teat, p=0.026). There was significant correlation between the SWV values for long head of biceps femoris muscle and knee spasticity (Spearman rank teat, p=0.022). Conclusion ARFI demonstrated a difference in muscle stiffness in the GCM between patients with spastic SCI and those without spasticity. This finding suggested that stiffness of muscles increased in spastic lower extremity of early SCI patients. ARFI imaging is a valuable tool for noninvasive assessment of the stiffness of the spastic muscle and has the potential to identify pathomechanical changes of the tissue associated with SCI. PMID:26161345

Minimizing water consumption when producing hydropower

NASA Astrophysics Data System (ADS)

Leon, A. S.

2015-12-01

In 2007, hydropower accounted for only 16% of the world electricity production, with other renewable sources totaling 3%. Thus, it is not surprising that when alternatives are evaluated for new energy developments, there is strong impulse for fossil fuel or nuclear energy as opposed to renewable sources. However, as hydropower schemes are often part of a multipurpose water resources development project, they can often help to finance other components of the project. In addition, hydropower systems and their associated dams and reservoirs provide human well-being benefits, such as flood control and irrigation, and societal benefits such as increased recreational activities and improved navigation. Furthermore, hydropower due to its associated reservoir storage, can provide flexibility and reliability for energy production in integrated energy systems. The storage capability of hydropower systems act as a regulating mechanism by which other intermittent and variable renewable energy sources (wind, wave, solar) can play a larger role in providing electricity of commercial quality. Minimizing water consumption for producing hydropower is critical given that overuse of water for energy production may result in a shortage of water for other purposes such as irrigation, navigation or fish passage. This paper presents a dimensional analysis for finding optimal flow discharge and optimal penstock diameter when designing impulse and reaction water turbines for hydropower systems. The objective of this analysis is to provide general insights for minimizing water consumption when producing hydropower. This analysis is based on the geometric and hydraulic characteristics of the penstock, the total hydraulic head and the desired power production. As part of this analysis, various dimensionless relationships between power production, flow discharge and head losses were derived. These relationships were used to withdraw general insights on determining optimal flow discharge and optimal penstock diameter. For instance, it was found that for minimizing water consumption, the ratio of head loss to gross head should not exceed about 15%. Two examples of application are presented to illustrate the procedure for determining optimal flow discharge and optimal penstock diameter for impulse and reaction turbines.

Vestibular dysfunction in Turner syndrome: a case report.

PubMed

Baxter, Michael; Agrawal, Yuri

2014-02-01

Turner syndrome is a well-known cause of sensorineural hearing loss, and the lack of estrogen has been implicated in cochlear dysfunction. It has never been associated with vestibular dysfunction. We report a case of a patient with Turner syndrome who was found to have bilateral vestibular dysfunction based on video-oculography (VOG) testing. A single patient with a history of Turner syndrome who was found to have significant bilateral vestibular dysfunction. After noticing a deficit in the vestibulo-ocular reflexes on qualitative horizontal head impulse examination, the patient underwent VOG testing. VOG testing quantatively measures angular vestibulo-ocular reflex (AVOR) gain in the horizontal semicircular canal plane. AVOR gain represents the eye movement response to a head movement; in normal individuals the eye movement is fully compensatory and gain values are close to unity. VOG results showed AVOR gains of 0.29 and 0.36 on the right and left sides, respectively. We have presented a case of a woman with Turner syndrome with asymptomatic vestibular dysfunction demonstrated with VOG testing. Although there is a documented relationship between Turner syndrome and sensorineural hearing loss, there are no previous studies or case reports linking Turner syndrome and vestibular dysfunction. Additional research and added vigilance in monitoring Turner syndrome patients may be warranted.

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

33 CFR 183.586 - Pressure impulse test.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.586 Pressure impulse test. A fuel... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Pressure impulse test. 183.586... pressure test under § 183.580. (b) If the tank is non-metallic, fill it to capacity with a gasoline that...

Enhanced Vertical Perception through Head-Related Impulse Response Customization Based on Pinna Response Tuning in the Median Plane

NASA Astrophysics Data System (ADS)

Shin, Ki Hoon; Park, Youngjin

Human's ability to perceive elevation of a sound and distinguish whether a sound is coming from the front or rear strongly depends on the monaural spectral features of the pinnae. In order to realize an effective virtual auditory display by HRTF (head-related transfer function) customization, the pinna responses were isolated from the median HRIRs (head-related impulse responses) of 45 individual HRIRs in the CIPIC HRTF database and modeled as linear combinations of 4 or 5 basic temporal shapes (basis functions) per each elevation on the median plane by PCA (principal components analysis) in the time domain. By tuning the weight of each basis function computed for a specific height to replace the pinna response in the KEMAR HRIR at the same height with the resulting customized pinna response and listening to the filtered stimuli over headphones, 4 individuals with normal hearing sensitivity were able to create a set of HRIRs that outperformed the KEMAR HRIRs in producing vertical effects with reduced front/back ambiguity in the median plane. Since the monaural spectral features of the pinnae are almost independent of azimuthal variation of the source direction, similar vertical effects could also be generated at different azimuthal directions simply by varying the ITD (interaural time difference) according to the direction as well as the size of each individual's own head.

Assessment of the Effectiveness of Combat Eyewear Protection Against Blast Overpressure.

PubMed

Sundaramurthy, A; Skotak, M; Alay, E; Unnikrishnan, G; Mao, H; Duan, X; Williams, S T; Harding, T H; Chandra, N; Reifman, J

2018-07-01

It is unclear whether combat eyewear used by U. S. Service members is protective against blast overpressures (BOPs) caused by explosive devices. Here, we investigated the mechanisms by which BOP bypasses eyewear and increases eye surface pressure. We performed experiments and developed three-dimensional (3D) finite element (FE) models of a head form (HF) equipped with an advanced combat helmet (ACH) and with no eyewear, spectacles, or goggles in a shock tube at three BOPs and five head orientations relative to the blast wave. Overall, we observed good agreement between experimental and computational results, with average discrepancies in impulse and peak-pressure values of less than 15% over 90 comparisons. In the absence of eyewear and depending on the head orientation, we identified three mechanisms that contributed to pressure loading on the eyes. Eyewear was most effective at 0 deg orientation, with pressure attenuation ranging from 50 (spectacles) to 80% (goggles) of the peak pressures observed in the no-eyewear configuration. Spectacles and goggles were considerably less effective when we rotated the HF in the counter-clockwise direction around the superior-inferior axis of the head. Surprisingly, at certain orientations, spectacles yielded higher maximum pressures (80%) and goggles yielded larger impulses (150%) than those observed without eyewear. The findings from this study will aid in the design of eyewear that provides better protection against BOP.

Predictive properties of the video head impulse test: measures of caloric symmetry and self-report dizziness handicap.

PubMed

McCaslin, Devin L; Jacobson, Gary P; Bennett, Marc L; Gruenwald, Jill M; Green, Andrea P

2014-01-01

The purpose of this investigation was to determine whether a predictable relationship existed between self-reported dizziness handicap and video Head Impulse Test (vHIT) results in a large sample of patients reporting to a dizziness clinic. Secondary objectives included describing the characteristics of the vHIT ipsilesional and contralesional vestibulo-ocular reflex slow-phase velocity in patients with varying levels of canal paresis. Finally, the authors calculated the sensitivity and specificity of the vHIT for detecting horizontal semicircular canal impairment using the caloric test as the "gold standard." Participants were 115 adults presenting to a tertiary medical care center with symptoms of dizziness. Participants were administered a measure of self-report dizziness handicap (i.e., Dizziness Handicap Inventory) and underwent caloric testing and vHIT at the same appointment. Results showed that (1) there were no significant group differences (i.e., vHIT normal versus vHIT abnormal) in the Dizziness Handicap Inventory total score, (2) both ipsilesional and contralateral velocity gain decreased with increases in caloric paresis, and (3) a caloric asymmetry of 39.5% was determined to be the cutoff that maximized discrimination of vHIT outcome. The level of self-reported dizziness handicap is not predicted by the outcome of the vHIT, which is consistent with the majority of published reports describing the poor relationship between quantitative tests of vestibular function and dizziness handicap. Further, the study findings have demonstrated that vHIT and caloric data are not redundant, and each test provides unique information regarding the functional integrity of the horizontal semicircular canal at different points on the frequency spectrum. The vHIT does offer some advantages over caloric testing, but at the expense of sensitivity. The vHIT can be completed in less time, is not noxious to the patient, and requires very little laboratory space. However, the study data show that a caloric asymmetry of 39.5% is required to optimize discrimination between an abnormal and normal vHIT. It is the authors' contention that the vHIT is a complementary test to the balance function examination and should viewed as such rather than as a replacement for caloric testing.

Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moss, W C; King, M J; Blackman, E G

In their Contributed Article, Nyein et al. (1,2) present numerical simulations of blast waves interacting with a helmeted head and conclude that a face shield may significantly mitigate blast induced traumatic brain injury (TBI). A face shield may indeed be important for future military helmets, but the authors derive their conclusions from a much smaller explosion than typically experienced on the battlefield. The blast from the 3.16 gm TNT charge of (1) has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 10 atm, 0.25 ms, and 3.9 psi-ms at the front of the head (14 cmmore » from charge), and 1.4 atm, 0.32 ms, and 1.7 psi-ms at the back of a typical 20 cm head (34 cm from charge). The peak pressure of the wave decreases by a factor of 7 as it traverses the head. The blast conditions are at the threshold for injury at the front of the head, but well below threshold at the back of the head (4). The blast traverses the head in 0.3 ms, roughly equal to the positive phase duration of the blast. Therefore, when the blast reaches the back of the head, near ambient conditions exist at the front. Because the headform is so close to the charge, it experiences a wave with significant curvature. By contrast, a realistic blast from a 2.2 kg TNT charge ({approx} an uncased 105 mm artillery round) is fatal at an overpressure of 10 atm (4). For an injury level (4) similar to (1), a 2.2 kg charge has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 2.1 atm, 2.3 ms, and 18 psi-ms at the front of the head (250 cm from charge), and 1.8 atm, 2.5 ms, and 16.8 psi-ms at the back of the head (270 cm from charge). The peak pressure decreases by only a factor of 1.2 as it traverses the head. Because the 0.36 ms traversal time is much smaller than the positive phase duration, pressures on the head become relatively uniform when the blast reaches the back of the head. The larger standoff implies that the headform locally experiences a nearly planar blast wave. Also, the positive phase durations and blast impulses are much larger than those of (1). Consequently, the blast model used in (1) is spatially and temporally very different from a military blast. It would be useful to repeat the calculations using military blast parameters. Finally, (1) overlooks a significant part of (5). On page 1 and on page 3, (1) states that (5) did not consider helmet pads. But pages pages 3 and 4 of (5) present simulations of blast wave propagation across an ACH helmeted head form with and without pads. (5) states that when the pads are present, the 'underwash' of air under the helmet is blocked when compared to the case without. (1) reaches this same conclusion, but reports it as a new result rather than a confirmation of that already found in (5).« less

Completed suicide in a case of clinically diagnosed progressive supranuclear palsy.

PubMed

Wiener, Jennifer; Moran, Maria T; Haut, Marc W

2015-08-01

We present the clinical history and the cognitive and behavioral presentations of a male patient with suspected progressive supranuclear palsy (PSP) who fatally shot himself in the head. We believe his act of suicide was the consequence of impulsivity, rather than primary depression or mood disturbance. In cases of suspected PSP and other atypical parkinsonisms, health professionals must be aware of neurobehavioral risk factors for suicide attempts and completions to promote patient safety; however, the literature on this topic is sparse. Our case highlights the potentially lethal consequences of impulsivity and other neuropsychiatric symptoms in PSP and related syndromes.

The video ocular counter-roll (vOCR): a clinical test to detect loss of otolith-ocular function

PubMed Central

Otero-Millan, Jorge; Treviño, Carolina; Winnick, Ariel; Zee, David S.; Carey, John P.; Kheradmand, Amir

2017-01-01

Conclusion vOCR can detect loss of otolith-ocular function without specifying the side of vestibular loss. Since vOCR is measured with a simple head tilt maneuver, it can be potentially used as a bedside clinical test in combination with video head impulse test. Objective Video-oculography (VOG) goggles are being integrated into the bedside assessment of patients with vestibular disorders. Lacking, however, is a method to evaluate otolith function. This study validated a VOG test for loss of otolith function. Methods VOG was used to measure ocular counter-roll (vOCR) in 12 healthy controls, 14 patients with unilateral vestibular loss (UVL), and six patients with bilateral vestibular loss (BVL) with a static lateral head tilt of 30°. The results were compared with vestibular evoked myogenic potentials (VEMP), a widely-used laboratory test of otolith function. Results The average vOCR for healthy controls (4.6°) was significantly different from UVL (2.7°) and BVL (1.6°) patients (p < 0.0001). The vOCR and VEMP measurements were correlated across subjects, especially the click and tap oVEMPs (click oVEMP R = 0.45, tap oVEMP R = 0.51; p < 0.0003). The receiver operator characteristic (ROC) analysis showed that vOCR and VEMPs detected loss of otolith function equally well. The best threshold for vOCR to detect vestibular loss was at 3°. The vOCR values from the side of vestibular loss and the healthy side were not different in UVL patients (2.53° vs 2.8°; p = 0.59). PMID:28084887

Impaired Decisional Impulsivity in Pathological Videogamers

PubMed Central

Irvine, Michael A.; Worbe, Yulia; Bolton, Sorcha; Harrison, Neil A.; Bullmore, Edward T.; Voon, Valerie

2013-01-01

Background Pathological gaming is an emerging and poorly understood problem. Impulsivity is commonly impaired in disorders of behavioural and substance addiction, hence we sought to systematically investigate the different subtypes of decisional and motor impulsivity in a well-defined pathological gaming cohort. Methods Fifty-two pathological gaming subjects and age-, gender- and IQ-matched healthy volunteers were tested on decisional impulsivity (Information Sampling Task testing reflection impulsivity and delay discounting questionnaire testing impulsive choice), and motor impulsivity (Stop Signal Task testing motor response inhibition, and the premature responding task). We used stringent diagnostic criteria highlighting functional impairment. Results In the Information Sampling Task, pathological gaming participants sampled less evidence prior to making a decision and scored fewer points compared with healthy volunteers. Gaming severity was also negatively correlated with evidence gathered and positively correlated with sampling error and points acquired. In the delay discounting task, pathological gamers made more impulsive choices, preferring smaller immediate over larger delayed rewards. Pathological gamers made more premature responses related to comorbid nicotine use. Greater number of hours played also correlated with a Motivational Index. Greater frequency of role playing games was associated with impaired motor response inhibition and strategy games with faster Go reaction time. Conclusions We show that pathological gaming is associated with impaired decisional impulsivity with negative consequences in task performance. Decisional impulsivity may be a potential target in therapeutic management. PMID:24146789

The Stomach-Derived Hormone Ghrelin Increases Impulsive Behavior

PubMed Central

Anderberg, Rozita H; Hansson, Caroline; Fenander, Maya; Richard, Jennifer E; Dickson, Suzanne L; Nissbrandt, Hans; Bergquist, Filip; Skibicka, Karolina P

2016-01-01

Impulsivity, defined as impaired decision making, is associated with many psychiatric and behavioral disorders, such as attention-deficit/hyperactivity disorder as well as eating disorders. Recent data indicate that there is a strong positive correlation between food reward behavior and impulsivity, but the mechanisms behind this relationship remain unknown. Here we hypothesize that ghrelin, an orexigenic hormone produced by the stomach and known to increase food reward behavior, also increases impulsivity. In order to assess the impact of ghrelin on impulsivity, rats were trained in three complementary tests of impulsive behavior and choice: differential reinforcement of low rate (DRL), go/no-go, and delay discounting. Ghrelin injection into the lateral ventricle increased impulsive behavior, as indicated by reduced efficiency of performance in the DRL test, and increased lever pressing during the no-go periods of the go/no-go test. Central ghrelin stimulation also increased impulsive choice, as evidenced by the reduced choice for large rewards when delivered with a delay in the delay discounting test. In order to determine whether signaling at the central ghrelin receptors is necessary for maintenance of normal levels of impulsive behavior, DRL performance was assessed following ghrelin receptor blockade with central infusion of a ghrelin receptor antagonist. Central ghrelin receptor blockade reduced impulsive behavior, as reflected by increased efficiency of performance in the DRL task. To further investigate the neurobiological substrate underlying the impulsivity effect of ghrelin, we microinjected ghrelin into the ventral tegmental area, an area harboring dopaminergic cell bodies. Ghrelin receptor stimulation within the VTA was sufficient to increase impulsive behavior. We further evaluated the impact of ghrelin on dopamine-related gene expression and dopamine turnover in brain areas key in impulsive behavior control. This study provides the first demonstration that the stomach-produced hormone ghrelin increases impulsivity and also indicates that ghrelin can change two major components of impulsivity—motor and choice impulsivity. PMID:26424164

Manic symptoms and impulsivity during bipolar depressive episodes

PubMed Central

Swann, Alan C; Moeller, F Gerard; Steinberg, Joel L; Schneider, Laurie; Barratt, Ernest S; Dougherty, Donald M

2009-01-01

Objectives In contrast to the extensive literature on the frequent occurrence of depressive symptoms in manic patients, there is little information about manic symptoms in bipolar depressions. Impulsivity is a prominent component of the manic syndrome, so manic features during depressive syndromes may be associated with impulsivity and its consequences, including increased risk of substance abuse and suicidal behavior. Therefore, we investigated the prevalence of manic symptoms and their relationships to impulsivity and clinical characteristics in patients with bipolar depressive episodes. Methods In 56 bipolar I or II depressed subjects, we investigated the presence of manic symptoms, using Mania Rating Scale (MRS) scores from the Schedule for Affective Disorders and Schizophrenia (SADS), and examined its association with other psychiatric symptoms (depression, anxiety, and psychosis), age of onset, history of alcohol and/or other substance abuse and of suicidal behavior, and measures of impulsivity. Results MRS ranged from 0 to 29 (25th–75th percentile, range 4–13), and correlated significantly with anxiety and psychosis, but not with depression, suggesting the superimposition of a separate psychopathological mechanism. Impulsivity and history of substance abuse, head trauma, or suicide attempt increased with increasing MRS. Receiver-operating curve analysis showed that MRS could divide patients into two groups based on history of alcohol abuse and suicide attempt, with an inflection point corresponding to an MRS score of 6. Discussion Even modest manic symptoms during bipolar depressive episodes were associated with greater impulsivity, and with histories of alcohol abuse and suicide attempts. Manic symptoms during depressive episodes suggest the presence of a potentially dangerous combination of depression and impulsivity. PMID:17430294

Testing the Relations Between Impulsivity-Related Traits, Suicidality, and Nonsuicidal Self-Injury: A Test of the Incremental Validity of the UPPS Model

PubMed Central

Lynam, Donald R.; Miller, Joshua D.; Miller, Drew J.; Bornovalova, Marina A.; Lejuez, C. W.

2011-01-01

Borderline personality disorder (BPD) has received significant attention as a predictor of suicidal behavior (SB) and nonsuicidal self-injury (NSSI). Despite significant promise, trait impulsivity has received less attention. Understanding the relations between impulsivity and SB and NSSI is confounded, unfortunately, by the heterogeneous nature of impulsivity. This study examined the relations among 4 personality pathways to impulsive behavior studied via the UPPS model of impulsivity and SB and NSSI in a residential sample of drug abusers (N = 76). In this study, we tested whether these 4 impulsivity-related traits (i.e., Negative Urgency, Sensation Seeking, Lack of Premeditation, and Lack of Perseverance) provide incremental validity in the statistical prediction of SB and NSSI above and beyond BPD; they do. We also tested whether BPD symptoms provide incremental validity in the prediction of SB and NSSI above and beyond these impulsivity-related traits; they do not. In addition to the main effects of Lack of Premeditation and Negative Urgency, we found evidence of a robust interaction between these 2 personality traits. The current results argue strongly for the consideration of these 2 impulsivity-related domains—alone and in interaction—when attempting to understand and predict SB and NSSI. PMID:21833346

Testing the relations between impulsivity-related traits, suicidality, and nonsuicidal self-injury: a test of the incremental validity of the UPPS model.

PubMed

Lynam, Donald R; Miller, Joshua D; Miller, Drew J; Bornovalova, Marina A; Lejuez, C W

2011-04-01

Borderline personality disorder (BPD) has received significant attention as a predictor of suicidal behavior (SB) and nonsuicidal self-injury (NSSI). Despite significant promise, trait impulsivity has received less attention. Understanding the relations between impulsivity and SB and NSSI is confounded, unfortunately, by the heterogeneous nature of impulsivity. This study examined the relations among 4 personality pathways to impulsive behavior studied via the UPPS model of impulsivity and SB and NSSI in a residential sample of drug abusers (N = 76). In this study, we tested whether these 4 impulsivity-related traits (i.e., Negative Urgency, Sensation Seeking, Lack of Premeditation, and Lack of Perseverance) provide incremental validity in the statistical prediction of SB and NSSI above and beyond BPD; they do. We also tested whether BPD symptoms provide incremental validity in the prediction of SB and NSSI above and beyond these impulsivity-related traits; they do not. In addition to the main effects of Lack of Premeditation and Negative Urgency, we found evidence of a robust interaction between these 2 personality traits. The current results argue strongly for the consideration of these 2 impulsivity-related domains--alone and in interaction--when attempting to understand and predict SB and NSSI.

Off-Axis and Angular Impulse Measurements on a Lightcraft Engine

NASA Astrophysics Data System (ADS)

Libeau, Michael; Myrabo, Leik

2005-04-01

A laser pulse into a Lightcraft engine applies three linear impulses and three angular impulses to the vehicle that depend on the engine's position and orientation with respect to the laser beam. The magnitudes on this impulsive reaction determine the vehicle's autonomous beam-riding characteristics. The impulsive reaction applied to the laser Lightcraft is examined and a device capable of measuring the reaction is designed and tested. Previous work has examined only the linear impulse acting in the thrust direction but the new apparatus, termed the Angular Impulse Measuring Device (AIMD), experimentally measures the dominant side impulse and dominant pitching angular impulse generated by the engine after a laser-strike. Recent tests of an 11/10 scale Model 200 Lightcraft were conducted using a 10KW Army laser at White Sands Missile Range. The resulting measurements are presented as a function of laser beam position.

Pharmacologic dissociation between impulsivity and alcohol drinking in High Alcohol Preferring mice

PubMed Central

Oberlin, Brandon G.; Bristow, R. Evan; Heighton, Meredith E.; Grahame, Nicholas J.

2014-01-01

Background Impulsivity is genetically correlated with, and precedes addictive behaviors and alcoholism. If impulsivity or attention is causally related to addiction, certain pharmacological manipulations of impulsivity and/or attention may affect alcohol drinking, and vice versa. The current studies were designed to explore the relationship among impulsivity, drinking, and vigilance in selectively bred High Alcohol Preferring (HAP) mice, a line that has previously demonstrated both high impulsivity and high alcohol consumption. Amphetamine, naltrexone and memantine were tested in a delay discounting (DD) task for their effects on impulsivity and vigilance. The same drugs and doses were also assessed for effects on alcohol drinking in a two-bottle choice test. Methods HAP mice were subjected to a modified version of adjusting amount DD using 0.5 sec and 10 sec delays to detect decreases and increases, respectively, in impulsive responding. In 2 experiments, mice were given amphetamine (0.4, 0.8 or 1.2 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) before DD testing. Another pair of studies used scheduled access, two-bottle choice drinking to assess effects of amphetamine (0.4, 1.2, or 3.0 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) on alcohol consumption. Results Amphetamine dose-dependently reduced impulsivity and vigilance decrement in DD, but similar doses left alcohol drinking unaffected. Naltrexone and memantine decreased alcohol intake at doses that did not affect water drinking, but had no effects on impulsivity or vigilance decrement in the DD task. Conclusions Contrary to our hypothesis, none of the drugs tested here, while effective either on alcohol drinking or impulsivity, decreased both behaviors. These findings suggest that the genetic association between drinking and impulsivity observed in this population is mediated by mechanisms other than those targeted by the drugs tested in these studies. PMID:20491739

Extracting the frequencies of the pinna spectral notches in measured head related impulse responses

NASA Astrophysics Data System (ADS)

Raykar, Vikas C.; Duraiswami, Ramani; Yegnanarayana, B.

2005-07-01

The head related impulse response (HRIR) characterizes the auditory cues created by scattering of sound off a person's anatomy. The experimentally measured HRIR depends on several factors such as reflections from body parts (torso, shoulder, and knees), head diffraction, and reflection/diffraction effects due to the pinna. Structural models (Algazi et al., 2002; Brown and Duda, 1998) seek to establish direct relationships between the features in the HRIR and the anatomy. While there is evidence that particular features in the HRIR can be explained by anthropometry, the creation of such models from experimental data is hampered by the fact that the extraction of the features in the HRIR is not automatic. One of the prominent features observed in the HRIR, and one that has been shown to be important for elevation perception, are the deep spectral notches attributed to the pinna. In this paper we propose a method to robustly extract the frequencies of the pinna spectral notches from the measured HRIR, distinguishing them from other confounding features. The method also extracts the resonances described by Shaw (1997). The techniques are applied to the publicly available CIPIC HRIR database (Algazi et al., 2001c). The extracted notch frequencies are related to the physical dimensions and shape of the pinna.

Impulsivity and the 5-HTTLPR Polymorphism in a Non-Clinical Sample

PubMed Central

Lage, Guilherme M.; Malloy-Diniz, Leandro F.; Matos, Lorena O.; Bastos, Marisa A. R.; Abrantes, Suzana S. C.; Corrêa, Humberto

2011-01-01

Background Impulsivity has been associated with serotonergic system functions. However, few researchers have investigated the relationship between a polymorphism in the promoter of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. The aim of this study was to investigate the relationship between a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. Methodology/Principal Findings We administered two neuropsychological tests, the Continuous Performance Task and the Iowa Gambling Task, to 127 healthy participants to measure their levels of motor, attentional and non-planning impulsivity. Then, these participants were grouped by genotype and gender, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional, motor and non-planning impulsivity. Conclusions/Significance Our results suggest that 5-HTTLPR genotype is not significantly associated with subsets of impulsive behavior in a non-clinical sample when measured by neuropsychological tests. These findings are discussed in terms of the sensitivity of neuropsychological tests to detect impulsivity in a non-clinical population and the role of gender and race in the relationship between the 5-HTTLPR and impulsivity. PMID:21386887

Vertical eye position-dependence of the human vestibuloocular reflex during passive and active yaw head rotations.

PubMed

Thurtell, M J; Black, R A; Halmagyi, G M; Curthoys, I S; Aw, S T

1999-05-01

Vertical eye position-dependence of the human vestibuloocular reflex during passive and active yaw head rotations. The effect of vertical eye-in-head position on the compensatory eye rotation response to passive and active high acceleration yaw head rotations was examined in eight normal human subjects. The stimuli consisted of brief, low amplitude (15-25 degrees ), high acceleration (4,000-6,000 degrees /s2) yaw head rotations with respect to the trunk (peak velocity was 150-350 degrees /s). Eye and head rotations were recorded in three-dimensional space using the magnetic search coil technique. The input-output kinematics of the three-dimensional vestibuloocular reflex (VOR) were assessed by finding the difference between the inverted eye velocity vector and the head velocity vector (both referenced to a head-fixed coordinate system) as a time series. During passive head impulses, the head and eye velocity axes aligned well with each other for the first 47 ms after the onset of the stimulus, regardless of vertical eye-in-head position. After the initial 47-ms period, the degree of alignment of the eye and head velocity axes was modulated by vertical eye-in-head position. When fixation was on a target 20 degrees up, the eye and head velocity axes remained well aligned with each other. However, when fixation was on targets at 0 and 20 degrees down, the eye velocity axis tilted forward relative to the head velocity axis. During active head impulses, the axis tilt became apparent within 5 ms of the onset of the stimulus. When fixation was on a target at 0 degrees, the velocity axes remained well aligned with each other. When fixation was on a target 20 degrees up, the eye velocity axis tilted backward, when fixation was on a target 20 degrees down, the eye velocity axis tilted forward. The findings show that the VOR compensates very well for head motion in the early part of the response to unpredictable high acceleration stimuli-the eye position- dependence of the VOR does not become apparent until 47 ms after the onset of the stimulus. In contrast, the response to active high acceleration stimuli shows eye position-dependence from within 5 ms of the onset of the stimulus. A model using a VOR-Listing's law compromise strategy did not accurately predict the patterns observed in the data, raising questions about how the eye position-dependence of the VOR is generated. We suggest, in view of recent findings, that the phenomenon could arise due to the effects of fibromuscular pulleys on the functional pulling directions of the rectus muscles.

A Study of Impulsivity in Low-Achieving and High-Achieving Boys from Lower Income Homes. Final Report.

ERIC Educational Resources Information Center

Cohen, Shirley

The purpose of this study was to explore the concept of impulsivity as a stylistic dimension affecting cognitive behavior, and whether impulsivity operates as a comprehensive, inflexible orientation in low achievers more than in high achievers. The Matching Familiar Figures Test, the Porteus Maze Test, and the Stroop Color-Word Test were used to…

Impulsivity and overeating in children in the absence and presence of hunger.

PubMed

Nederkoorn, Chantal; Dassen, Fania C M; Franken, Loes; Resch, Christine; Houben, Katrijn

2015-10-01

Overweight children appear to be more responsive to environmental, hedonic cues and easily overeat in the current obesogenic environment. They are also found to overeat in the absence of hunger, and this overeating seems related to impulsivity: impulsive participants are more prone to external eating. However, some studies showed that impulsive adults are also more prone to hunger cues: impulsive participants overate especially when feeling hungry. This would mean impulsive people are more reactive to both external and internal cues. The overeating was limited to palatable high energy-dense foods: hunger made them fancy a snack. In the current study, we wanted to test the interaction between impulsivity, hunger and consumption of food type in children. Impulsivity was measured in 88 children between the ages of 7 and 9. Next, half of the participants performed a taste test before their own regular lunch and half of the participants immediately after their lunch. During the taste test, low, medium and high energy-dense food items were presented. Results showed that impulsive children ate more high energy-dense foods than low impulsive children, both before and after their lunch. No differences were found on low or medium energy-dense foods. Impulsive children therefore showed normal sensitivity for internal hunger and satiety cues, but abnormal response to high energy-dense foods. This might render them vulnerable to tasty temptation in the environment and to weight gain in their future. Copyright © 2015 Elsevier Ltd. All rights reserved.

The 5-HTTLPR polymorphism, impulsivity and suicide behavior in euthymic bipolar patients.

PubMed

Malloy-Diniz, Leandro Fernandes; Neves, Fernando Silva; de Moraes, Paulo Henrique Paiva; De Marco, Luiz Armando; Romano-Silva, Marco Aurélio; Krebs, Marie-Odile; Corrêa, Humberto

2011-09-01

Suicide behavior is very frequent in Bipolar Disorder (BD) and they are both closely associated with impulsivity. Furthermore they are, impulsivity, BD and suicide behavior, associated with serotonergic function, at least partially, under genetic determinism and somewhat associated with the serotonin transporter gene polymorphism, the 5-HTTLPR. We aimed to assess different impulsivity components in BD sub-grouped by suicidal attempt and healthy controls. We hypothesized that the non-planning/cognitive impulsivity, could be more closely associated with suicidal behavior. We further associated 5-HTTLPR genotypes with neuropsychological results to test the hypothesis that this polymorphism is associated with cognitive impulsivity. We assessed 95 euthymic bipolar patients sub-grouped by suicidal attempt history in comparison with 94 healthy controls. All subjects underwent a laboratory assessment of impulsivity (Continuous Performance Test and Iowa Gambling Test). Furthermore the genotyping of 5-HTTLPR was performed in all subjects. We found that bipolar patients are more impulsive than healthy controls in all impulsivity dimensions we studied. Furthermore bipolar patients with a suicide attempt history have a greater cognitive impulsivity when compared to both bipolar patients without such a history as well when compared to healthy controls. No association was found between 5-HTTLPR genotypes and neuropsychological measures of impulsive behavior. The sample studied can be considered small and a potentially confounding variable - medication status - was not controlled. A lifetime suicide attempt seems associated with cognitive impulsivity independently of the socio-demographic and clinical variables studied as well with 5-HTTLPR genotype. Further studies in larger samples are necessary. Copyright © 2011 Elsevier B.V. All rights reserved.

Striatal dopamine d2/d3 receptor availability is reduced in methamphetamine dependence and is linked to impulsivity.

PubMed

Lee, Buyean; London, Edythe D; Poldrack, Russell A; Farahi, Judah; Nacca, Angelo; Monterosso, John R; Mumford, Jeanette A; Bokarius, Andrew V; Dahlbom, Magnus; Mukherjee, Jogeshwar; Bilder, Robert M; Brody, Arthur L; Mandelkern, Mark A

2009-11-25

While methamphetamine addiction has been associated with both impulsivity and striatal dopamine D(2)/D(3) receptor deficits, human studies have not directly linked the latter two entities. We therefore compared methamphetamine-dependent and healthy control subjects using the Barratt Impulsiveness Scale (version 11, BIS-11) and positron emission tomography with [(18)F]fallypride to measure striatal dopamine D(2)/D(3) receptor availability. The methamphetamine-dependent subjects reported recent use of the drug 3.3 g per week, and a history of using methamphetamine, on average, for 12.5 years. They had higher scores than healthy control subjects on all BIS-11 impulsiveness subscales (p < 0.001). Volume-of-interest analysis found lower striatal D(2)/D(3) receptor availability in methamphetamine-dependent than in healthy control subjects (p < 0.01) and a negative relationship between impulsiveness and striatal D(2)/D(3) receptor availability in the caudate nucleus and nucleus accumbens that reached statistical significance in methamphetamine-dependent subjects. Combining data from both groups, voxelwise analysis indicated that impulsiveness was related to D(2)/D(3) receptor availability in left caudate nucleus and right lateral putamen/claustrum (p < 0.05, determined by threshold-free cluster enhancement). In separate group analyses, correlations involving the head and body of the caudate and the putamen of methamphetamine-dependent subjects and the lateral putamen/claustrum of control subjects were observed at a weaker threshold (p < 0.12 corrected). The findings suggest that low striatal D(2)/D(3) receptor availability may mediate impulsive temperament and thereby influence addiction.

Impulsivity and test meal intake among women with bulimia nervosa

PubMed Central

Sysko, Robyn; Ojserkis, Rachel; Schebendach, Janet; Evans, Suzette M.; Hildebrandt, Tom; Walsh, B. Timothy

2017-01-01

Many patients with bulimia nervosa (BN) also meet criteria for a lifetime alcohol use disorder (AUD). In order to understand possible mechanisms contributing to the co-occurrence and perpetuation of these disorders, this study investigated the importance of impulsivity and test meal intake among patients with BN by comparing women with BN only (n = 18), BN and current/past AUDs (n = 13), and healthy controls (n = 12). All participants completed assessments of eating disorder symptoms, frequency of alcohol use, binge eating, and purging via questionnaires and semi-structured interviews over two sessions. Measures of impulsivity consisted of computerized and self-report measures, and laboratory test meals. Significant differences between individuals with BN with/without comorbid AUDs were not found for test meal intake, impulsivity measures, or self-reported psychological symptoms. As hypothesized, compared to healthy controls, individuals with BN had significantly higher scores on two subscales and the total score of the Barratt Impulsiveness Scale, a trait measure of impulsivity, and consumed significantly more calories in the binge instruction meal. Total Barratt Impulsiveness Scale scores were also significantly related to kcal consumed during the laboratory test meal when individuals were instructed to binge eat (BN groups). Data from this study add to the existing literature implicating impulsivity in the psychopathology of disorders of binge eating, including BN, and also support the use of laboratory meals as a symptom-specific measure of this trait in eating disorder populations. PMID:28077307

Impulsivity and test meal intake among women with bulimia nervosa.

PubMed

Sysko, Robyn; Ojserkis, Rachel; Schebendach, Janet; Evans, Suzette M; Hildebrandt, Tom; Walsh, B Timothy

2017-05-01

Many patients with bulimia nervosa (BN) also meet criteria for a lifetime alcohol use disorder (AUD). In order to understand possible mechanisms contributing to the co-occurrence and perpetuation of these disorders, this study investigated the importance of impulsivity and test meal intake among patients with BN by comparing women with BN only (n = 18), BN and current/past AUDs (n = 13), and healthy controls (n = 12). All participants completed assessments of eating disorder symptoms, frequency of alcohol use, binge eating, and purging via questionnaires and semi-structured interviews over two sessions. Measures of impulsivity consisted of computerized and self-report measures, and laboratory test meals. Significant differences between individuals with BN with/without comorbid AUDs were not found for test meal intake, impulsivity measures, or self-reported psychological symptoms. As hypothesized, compared to healthy controls, individuals with BN had significantly higher scores on two subscales and the total score of the Barratt Impulsiveness Scale, a trait measure of impulsivity, and consumed significantly more calories in the binge instruction meal. Total Barratt Impulsiveness Scale scores were also significantly related to kcal consumed during the laboratory test meal when individuals were instructed to binge eat (BN groups). Data from this study add to the existing literature implicating impulsivity in the psychopathology of disorders of binge eating, including BN, and also support the use of laboratory meals as a symptom-specific measure of this trait in eating disorder populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Low Pretreatment Impulsivity and High Medication Adherence Increase the Odds of Abstinence in a Trial of N-Acetylcysteine in Adolescents with Cannabis Use Disorder

PubMed Central

Bentzley, Jessica P.; Tomko, Rachel L.; Gray, Kevin M.

2016-01-01

Background In light of recent progress toward pharmacologic interventions to treat adolescent cannabis use disorder, it is important to consider which adolescent characteristics may be associated with a favorable response to treatment. This study presents secondary analyses from a parent randomized controlled trial of N-acetylcysteine (NAC) in adolescents with cannabis use disorder. We hypothesized high pretreatment impulsivity and medication non-adherence would be associated with reduced abstinence rates. Methods Participants were treatment-seeking adolescents (N = 115) who met criteria for cannabis use disorder and were assessed for pretreatment impulsivity. They received 1200 mg NAC or placebo orally twice daily for 8 weeks. An intent-to-treat analysis using a repeated-measures logistic regression model was used to relate pretreatment impulsivity (Barratt Impulsiveness Scale) and treatment group to abstinence rates, measured by urine cannabinoid tests. To explore mechanisms by which NAC may reduce cannabis use, relationships between impulsivity, adherence, and abstinence were assessed in a second statistical model using data from participants with recorded adherence and urine cannabinoid test results (n = 54). Results In the intent-to-treat analysis, low pretreatment impulsivity, NAC treatment, and negative baseline urine cannabinoid test results independently increased the odds of having negative urine cannabinoid tests during treatment (OR = 2.1, 2.3, 5.3 respectively). In the sample of participants with adherence data (n = 54), adherence tripled the odds of abstinence. Notably, the effect of adherence on abstinence was only observed in the NAC treatment group. Lastly, although the highly impulsive participants had reduced rates of abstinence, highly impulsive individuals adherent to NAC treatment had increased abstinence rates compared to non-adherent individuals. Conclusion Low impulsivity, NAC treatment, medication adherence, and baseline negative cannabinoid testing were associated with increased rates of abstinence in adolescents seeking treatment for cannabis use disorder. Efforts to optimize pharmacotherapy adherence may be particularly crucial for highly impulsive individuals. Understanding and addressing factors, such as impulsivity and adherence, which may affect outcomes, may aid in the successful evaluation and development of potentially promising pharmacotherapies. PMID:26827257

Delayed Immunomodulatory Effect of Cow Milk-Free Diet in Ménière's Disease.

PubMed

Di Berardino, Federica; Zanetti, Diego

2018-02-01

Since 1930, dietary modification has been proposed as adjunct treatment in Ménière's disease (MD) with different and controversial results. We report the case of a 42-year-old female suffering from definite MD and intermittent seasonal allergic rhino-conjunctivitis because it highlights the importance of evaluating the different combinations of defined causative elements in an atopic patient with MD. An immunological and audiological evaluation was performed, including pure-tone, speech, and immittance audiometry; glycerol dehydration test; bithermal caloric testing; video head impulse test; cervical vestibular evoked myogenic potentials; static posturography; and Dizziness Handicap Inventory questionnaire. A milk-free diet was crucial to relief from MD symptoms and a cow's milk challenge test was able to evoke them but vestibukar symptoms persist. The effect of dietary modification was evident only after specific immunotherapies against other allergens. This highlights the importance of evaluating different combinations of defined causative elements in the allergic treatment of MD.

International Comparison Test in Asia-Pacific Region for Impulse Voltage Measurements

NASA Astrophysics Data System (ADS)

Wakimoto, Takayuki; Ishii, Masaru; Goshima, Hisashi; Hino, Etsuhiro; Shimizu, Hiroyuki; Li, Yi; Ik-Soo, Kim

The national standard class divider for the lightning impulse voltage measurements in Japan was developed in 1998. After three years, the standard impulse voltage calibrator was manufactured, too. These standard equipment are used as an industrial standard, and the performance had been evaluated annually supported by Ministry of Economy, Trade and Industry (METI). The standard impulse measuring system including the standard divider participated in the worldwide comparison test and its good performance was confirmed in 1999. Another international comparison test was carried out among three countries in the Asia-Pacific region in 2004 again and the standard measuring system participated in the test. In this paper, the details and the results of the international comparison tests in 2004 are described.

Second-to-fourth digit ratio and impulsivity: a comparison between offenders and nonoffenders.

PubMed

Hanoch, Yaniv; Gummerum, Michaela; Rolison, Jonathan

2012-01-01

Personality characteristics, particularly impulsive tendencies, have long been conceived as the primary culprit in delinquent behavior. One crucial question to emerge from this line of work is whether impulsivity has a biological basis. To test this possibility, 44 male offenders and 46 nonoffenders completed the Eysenck Impulsivity Questionnaire, and had their 2D∶4D ratio measured. Offenders exhibited smaller right hand digit ratio measurements compared to non-offenders, but higher impulsivity scores. Both impulsivity and 2D∶4D ratio measurements significantly predicted criminality (offenders vs. nonoffenders). Controlling for education level, the 2D∶4D ratio measurements had remained a significant predictor of criminality, while impulsivity scores no longer predicted criminality significantly. Our data, thus, indicates that impulsivity but not 2D∶4D ratio measurements relate to educational attainment. As offenders varied in their number of previous convictions and the nature of their individual crimes, we also tested for differences in 2D∶4D ratio and impulsivity among offenders. Number of previous convictions did not correlate significantly with the 2D∶4D ratio measurements or impulsivity scores. Our study established a link between a biological marker and impulsivity among offenders (and lack thereof among non-offenders), which emphasise the importance of studying the relationship between biological markers, impulsivity and criminal behavior.

Project NEO Specific Impulse Testing Solutions

NASA Technical Reports Server (NTRS)

Baffa, Bill

2018-01-01

The Neo test stand is currently configured to fire a horizontally mounted rocket motor with up to 6500 lbf thrust. Currently, the Neo test stand can measure flow of liquid propellant and oxidizer, pressures residing in the closed system up to the combustion chamber. The current configuration does not have the ability to provide all data needed to compute specific impulse. This presents three methods to outfit the NEO test fixture with instrumentation allowing for calculation of specific impulse.

Impulsivity and the Sexes: Measurement and Structural Invariance of the UPPS-P Impulsive Behavior Scale

ERIC Educational Resources Information Center

Cyders, Melissa A.

2013-01-01

Before it is possible to test whether men and women differ in impulsivity, it is necessary to evaluate whether impulsivity measures are invariant across sex. The UPPS-P Impulsive Behavior Scale (negative urgency, lack of premeditation, lack of perseverance, and sensation seeking, with added subscale of positive urgency) is one measure of five…

Ground vibration test results of a JetStar airplane using impulsive sine excitation

NASA Technical Reports Server (NTRS)

Kehoe, Michael W.; Voracek, David F.

1989-01-01

Structural excitation is important for both ground vibration and flight flutter testing. The structural responses caused by this excitation are analyzed to determine frequency, damping, and mode shape information. Many excitation waveforms have been used throughout the years. The use of impulsive sine (sin omega t)/omega t as an excitation waveform for ground vibration testing and the advantages of using this waveform for flight flutter testing are discussed. The ground vibration test results of a modified JetStar airplane using impulsive sine as an excitation waveform are compared with the test results of the same airplane using multiple-input random excitation. The results indicated that the structure was sufficiently excited using the impulsive sine waveform. Comparisons of input force spectrums, mode shape plots, and frequency and damping values for the two methods of excitation are presented.

Spectral analysis of hearing protector impulsive insertion loss.

PubMed

Fackler, Cameron J; Berger, Elliott H; Murphy, William J; Stergar, Michael E

2017-01-01

To characterise the performance of hearing protection devices (HPDs) in impulsive-noise conditions and to compare various protection metrics between impulsive and steady-state noise sources with different characteristics. HPDs were measured per the impulsive test methods of ANSI/ASA S12.42- 2010 . Protectors were measured with impulses generated by both an acoustic shock tube and an AR-15 rifle. The measured data were analysed for impulse peak insertion loss (IPIL) and impulsive spectral insertion loss (ISIL). These impulsive measurements were compared to insertion loss measured with steady-state noise and with real-ear attenuation at threshold (REAT). Tested HPDs included a foam earplug, a level-dependent earplug and an electronic sound-restoration earmuff. IPIL for a given protector varied between measurements with the two impulse noise sources, but ISIL agreed between the two sources. The level-dependent earplug demonstrated level-dependent effects both in IPIL and ISIL. Steady-state insertion loss and REAT measurements tended to provide a conservative estimate of the impulsively-measured attenuation. Measurements of IPIL depend strongly on the source used to measure them, especially for HPDs with less attenuation at low frequencies. ISIL provides an alternative measurement of impulse protection and appears to be a more complete description of an HPD's performance.

Spectral analysis of hearing protector impulsive insertion loss

PubMed Central

Fackler, Cameron J.; Berger, Elliott H.; Murphy, William J.; Stergar, Michael E.

2017-01-01

Objective To characterize the performance of hearing protection devices in impulsive-noise conditions and to compare various protection metrics between impulsive and steady-state noise sources with different characteristics. Design Hearing protectors were measured per the impulsive test methods of ANSI/ASA S12.42-2010. Protectors were measured with impulses generated by both an acoustic shock tube and an AR-15 rifle. The measured data were analyzed for impulse peak insertion loss (IPIL) and impulsive spectral insertion loss (ISIL). These impulsive measurements were compared to insertion loss measured with steady-state noise and with real-ear attenuation at threshold (REAT). Study Sample Tested devices included a foam earplug, a level-dependent earplug, and an electronic sound-restoration earmuff. Results IPIL for a given protector varied between measurements with the two impulse noise sources, but ISIL agreed between the two sources. The level-dependent earplug demonstrated level-dependent effects both in IPIL and ISIL. Steady-state insertion loss and REAT measurements tended to provide a conservative estimate of the impulsively-measured attenuation. Conclusions Measurements of IPIL depend strongly on the source used to measure them, especially for hearing protectors with less attenuation at low frequencies. ISIL provides an alternative measurement of impulse protection and appears to be a more complete description of an HPD’s performance. PMID:27885881

Impulse Testing of Corporate-Fed Patch Array Antennas

NASA Technical Reports Server (NTRS)

Chamberlain, Neil F.

2011-01-01

This paper discusses a novel method for detecting faults in antenna arrays. The method, termed Impulse Testing, was developed for corporate-fed patch arrays where the element is fed by a probe and is shorted at its center. Impulse Testing was devised to supplement conventional microwave measurements in order to quickly verify antenna integrity. The technique relies on exciting each antenna element in turn with a fast pulse (or impulse) that propagates through the feed network to the output port of the antenna. The resulting impulse response is characteristic of the path through the feed network. Using an oscilloscope, a simple amplitude measurement can be made to detect faults. A circuit model of the antenna elements and feed network was constructed to assess various fault scenarios and determine fault-detection thresholds. The experimental setup and impulse measurements for two patch array antennas are presented. Advantages and limitations of the technique are discussed along with applications to other antenna array topologies

Impulsive-Analytic Disposition in Mathematical Problem Solving: A Survey and a Mathematics Test

ERIC Educational Resources Information Center

Lim, Kien H.; Wagler, Amy

2012-01-01

The Likelihood-to-Act (LtA) survey and a mathematics test were used in this study to assess students' impulsive-analytic disposition in the context of mathematical problem solving. The results obtained from these two instruments were compared to those obtained using two widely-used scales: Need for Cognition (NFC) and Barratt Impulsivity Scale…

The Latent Structure of Impulsivity: Impulsive Choice, Impulsive Action, and Impulsive Personality Traits

PubMed Central

MacKillop, James; Weafer, Jessica; Gray, Joshua; Oshri, Assaf; Palmer, Abraham; de Wit, Harriet

2016-01-01

Rationale Impulsivity has been strongly linked to addictive behaviors, but can be operationalized in a number of ways that vary considerably in overlap, suggesting multidimensionality. Objective This study tested the hypothesis that the latent structure among multiple measures of impulsivity would reflect three broad categories: impulsive choice, reflecting discounting of delayed rewards; impulsive action, reflecting ability to inhibit a prepotent motor response; and impulsive personality traits, reflecting self-reported attributions of self-regulatory capacity. Methods The study used a cross-sectional confirmatory factor analysis of multiple impulsivity assessments. Participants were 1252 young adults (62% female) with low levels of addictive behavior who were assessed in individual laboratory rooms at the University of Chicago and the University of Georgia. The battery comprised a delay discounting task, Monetary Choice Questionnaire, Conners Continuous Performance Test, Go/NoGo Task, Stop Signal Task, Barratt Impulsivity Scale, and the UPPS-P Impulsive Behavior Scale. Results The hypothesized three-factor model provided the best fit to the data, although Sensation Seeking was excluded from the final model. The three latent factors were largely unrelated to each other and were variably associated with substance use. Conclusions These findings support the hypothesis that diverse measures of impulsivity can broadly be organized into three categories that are largely distinct from one another. These findings warrant investigation among individuals with clinical levels of addictive behavior and may be applied to understanding the underlying biological mechanisms of these categories. PMID:27449350

A STUDY OF METHODS OF CONTROLLING IMPULSES.

ERIC Educational Resources Information Center

WHITESIDE, RAY

THE PERSON LESS ABLE TO CONTROL HIS IMPULSES IS ALSO APT TO EXHIBIT SOCIALLY DISVALUED BEHAVIOR. VOCATIONAL AND ACADEMIC FAILURE IS A PARTIAL CONSEQUENCE OF IMPULSIVENESS AND LACK OF SELF-CONTROL. TO INVESTIGATE IMPULSE CONTROL, TWO INSTRUMENTS BELIEVED TO MEASURE ATTRIBUTES OF OPPOSITE POLES OF THIS CONCEPT (SEQUENTIAL TESTS OF EDUCATIONAL…

Measurement of impulsive choice in rats: Same and alternate form test-retest reliability and temporal tracking

PubMed Central

Peterson, Jennifer R.; Hill, Catherine C.; Kirkpatrick, Kimberly

2016-01-01

Impulsive choice is typically measured by presenting smaller-sooner (SS) versus larger-later (LL) rewards, with biases towards the SS indicating impulsivity. The current study tested rats on different impulsive choice procedures with LL delay manipulations to assess same-form and alternate-form test-retest reliability. In the systematic-GE procedure (Green & Estle, 2003), the LL delay increased after several sessions of training; in the systematic-ER procedure (Evenden & Ryan, 1996), the delay increased within each session; and in the adjusting-M procedure (Mazur, 1987), the delay changed after each block of trials within a session based on each rat’s choices in the previous block. In addition to measuring choice behavior, we also assessed temporal tracking of the LL delays using the median times of responding during LL trials. The two systematic procedures yielded similar results in both choice and temporal tracking measures following extensive training, whereas the adjusting procedure resulted in relatively more impulsive choices and poorer temporal tracking. Overall, the three procedures produced acceptable same form test-retest reliability over time, but the adjusting procedure did not show significant alternate form test-retest reliability with the other two procedures. The results suggest that systematic procedures may supply better measurements of impulsive choice in rats. PMID:25490901

Liquid oxygen turbopump technology

NASA Technical Reports Server (NTRS)

Nielson, C. E.

1981-01-01

A small, high-pressure, LOX turbopump was designed, fabricated and tested. The pump is a single-stage centrifugal type with power to the pump supplied by a single-stage partial-admission axial-impulse turbine. Design conditions included an operating speed of 7330 rad/s (70,000 rpm), pump discharge pressure of 2977 N/sqcm (4318 psia), and a pump flowrate of 16.4 Kg/s (36.21 lb/s). The turbopump contains a self-compensating axial thrust balance piston to eliminate axial thrust loads on the bearings during steady-state operation. Testing of the turbopump was achieved usng a gaseous hydrogen high-pressure flow to drive the turbine, which generally is propelled by LOX/LH2 combustion products, at 1041K (1874 R) inlet temperature and at a design pressure ratio of 1.424. Test data obtained with the turbopump are presented which include head-flow-efficiency performance, suction performance, balance piston performance and LOX seal performance. Mechanical performance of the turbopump is also discussed.

Effect of amplitude and duration of impulsive pressure on endothelial permeability in in vitro fluid percussion trauma.

PubMed

Nakadate, Hiromichi; Inuzuka, Koji; Akanuma, Suguru; Kakuta, Akira; Aomura, Shigeru

2014-04-16

Intracranial pressure changes during head impact cause brain injuries such as vasogenic edema and cerebral contusion. However, the influence of impulsive pressure on endothelial function has not yet been fully studied in vitro. In this study, we developed a pressure loading device that produced positive and negative pressures by modifying an in vitro fluid percussion model and examined the effects of the amplitude and duration of the pressures on endothelial permeability. Human umbilical vein endothelial cells were subjected to three types of positive pressure (average amplitude/average duration of 352 kPa/23 ms, 73 kPa/27 ms, and 70 kPa/44 ms) and three types of negative pressure (-72 kPa/41 ms, -67 kPa/104 ms, and -91 kPa/108 ms), and the transendothelial electrical resistance (TEER) was measured between 15 min and 24 h after pressure loading for quantifying the formation of an integral monolayer of endothelial cells. After loading, vascular endothelial- (VE-) cadherin, an endothelium-specific cell-cell adhesion molecule involved in endothelial barrier function, was stained and observed using fluorescence microscopy. The pressure loading device could produce positive pressure pulses with amplitudes of 53-1348 kPa and durations of 9-29.1 ms and negative pressure pulses with amplitudes of -52 - -93 kPa and durations of 42.9-179.5 ms. The impulsive pressure reduced the TEER associated with the change in VE-cadherin localization. Additionally, TEER decreased considerably at 15 min and 6 h post-loading, with these changes being significant in positive pressure with larger amplitude and shorter duration and in all types of negative pressures compared to pre-loading. The changes in intracranial pressure during head impact impair endothelial barrier function by the disruption of the integrity of endothelial cell-cell junctions, and the degree of increase in endothelial permeability depends on the amplitude, duration, and direction (compressive and tensile) of the impulsive pressure.

Allelic variation in dopamine D2 receptor gene is associated with attentional impulsiveness on the Barratt Impulsiveness Scale (BIS-11).

PubMed

Taylor, Jasmine B; Cummins, Tarrant D R; Fox, Allison M; Johnson, Beth P; Tong, Janette H; Visser, Troy A W; Hawi, Ziarih; Bellgrove, Mark A

2017-01-20

Previous studies have postulated that noradrenergic and/or dopaminergic gene variations are likely to underlie individual differences in impulsiveness, however, few have shown this. The current study examined the relationship between catecholamine gene variants and self-reported impulsivity, as measured by the Barratt Impulsiveness Scale (Version 11; BIS-11) Methods: Six hundred and seventy-seven non-clinical adults completed the Barratt Impulsiveness Scale (BIS-11). DNA was analysed for a set of 142 single-nucleotide polymorphisms (SNPs) across 20 autosomal catecholamine genes. Association was tested using an additive regression model with permutation testing used to control for the influence of multiple comparison. Analysis revealed an influence of rs4245146 of the dopamine D2 receptor (DRD2) gene on the BIS-11 attention first-order factor, such that self-reported attentional impulsiveness increased in an additive fashion with each copy of the T allele. These findings provide preliminary evidence that allelic variation in DRD2 may influence impulsiveness by increasing the propensity for attentional lapses.

Acute alcohol effects on impulsivity: associations with drinking and driving behavior.

PubMed

McCarthy, Denis M; Niculete, Maria E; Treloar, Hayley R; Morris, David H; Bartholow, Bruce D

2012-12-01

Although drink drivers exhibit higher levels of trait impulsivity, no studies have tested the hypothesis that drink drivers experience increased impulsivity while intoxicated. We tested this hypothesis for two impulsivity constructs: delay discounting and behavioral inhibition. A within-subjects study comparing performance of drink drivers and non-drink drivers on behavioral measures of impulsivity in alcohol and no-beverage sessions. A laboratory setting at the University of Missouri. Twenty-nine young adults who were at least moderate drinkers were recruited from the local community and the University of Missouri. Impulsivity was assessed using the Two Choice Impulsivity Paradigm (TCIP) and the Stop-Signal Task. Participants also completed self-report measures of binge drinking and trait impulsivity. In the no-beverage session, TCIP impulsive choices did not differ between drinking and driving groups (P = 0.93). In the alcohol session, drink drivers made more TCIP impulsive choices on both the ascending (P < 0.01) and descending limb (P < 0.01) of the blood alcohol concentration curve than their peers who did not drink and drive. Drinking and driving groups did not differ on the Stop-Signal Task. Supplementary analyses indicated that effects for the TCIP were not explained by individual differences in trait impulsivity. Individuals who report having three or more drinks before driving show greater impulsivity when under the influence of alcohol than those who do not report heavy drinking before driving. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.

Acute alcohol effects on impulsivity: Associations with drinking and driving behavior

PubMed Central

McCarthy, Denis M.; Niculete, Maria E.; Treloar, Hayley R.; Morris, David H.; Bartholow, Bruce D.

2012-01-01

Aims Although drink drivers exhibit higher levels of trait impulsivity, no studies have tested the hypothesis that drink drivers experience increased impulsivity while intoxicated. We tested this hypothesis for two impulsivity constructs: delay discounting and behavioral inhibition. Design A within-subjects study comparing performance of drink drivers and non-drink drivers on behavioral measures of impulsivity in alcohol and no-beverage sessions. Setting A laboratory setting at the University of Missouri. Participants Twenty-nine young adults who were at least moderate drinkers were recruited from the local community and the University of Missouri. Measurements Impulsivity was assessed using the Two Choice Impulsivity Paradigm (TCIP) and the Stop-Signal Task. Participants also completed self-report measures of binge drinking and trait impulsivity. Findings In the no-beverage session, TCIP impulsive choices did not differ between drinking and driving groups (p = .93). In the alcohol session, drink drivers made more TCIP impulsive choices on both the ascending (p < .01) and descending limb (p < .01) of the blood alcohol concentration curve than their peers who did not drink and drive. Drinking and driving groups did not differ on the Stop-Signal Task. Supplementary analyses indicated that effects for the TCIP were not explained by individual differences in trait impulsivity. Conclusions Individuals who report having three or more drinks before driving show greater impulsivity when under the influence of alcohol than those who do not report heavy drinking before driving. PMID:22690907

The dynamics of head-on collisions of spherical stellar systems

NASA Astrophysics Data System (ADS)

Narasimhan, K. S. V. S.; Alladin, Saleh Mohammed

1986-12-01

Energy changes in a head-on collision between two unequal Plummer model stellar systems (galaxies) are studied analytically under the impulsive approximation. The variation of the disruptive effects within and the mass escape from systems widely differing in mass and scalelength ratios are determined, and some physical implications regarding the dynamical stability of the systems undergoing head-on collisions are indicated. It is found that if two systems differ considerably in size, both systems generally survive the collision if (1) the mass of the bigger is greater than about six times the mass of the smaller and (2) the density of the smaller is more than about twenty-five times the entity of the bigger system, when the velocity at minimum separation is equal to the parabolic velocity of escape.

Endeavour Impulse Tests

NASA Image and Video Library

2003-10-27

In the Orbiter Processing Facility, Eric Madaras, NASA-Langley Research Center, conducts impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

Sweet taste liking is associated with impulsive behaviors in humans

PubMed Central

Weafer, Jessica; Burkhardt, Anne; de Wit, Harriet

2014-01-01

Evidence from both human and animal studies suggests that sensitivity to rewarding stimuli is positively associated with impulsive behaviors, including both impulsive decision making and inhibitory control. The current study examined associations between the hedonic value of a sweet taste and two forms of impulsivity (impulsive choice and impulsive action) in healthy young adults (N = 100). Participants completed a sweet taste test in which they rated their liking of various sweetness concentrations. Subjects also completed measures of impulsive choice (delay discounting), and impulsive action (go/no-go task). Subjects who discounted more steeply (i.e., greater impulsive choice) liked the high sweetness concentration solutions more. By contrast, sweet liking was not related to impulsive action. These findings indicate that impulsive choice may be associated with heightened sensitivity to the hedonic value of a rewarding stimulus, and that these constructs might share common underlying neurobiological mechanisms. PMID:24987343

Objectively-measured impulsivity and attention-deficit/hyperactivity disorder (ADHD): testing competing predictions from the working memory and behavioral inhibition models of ADHD.

PubMed

Raiker, Joseph S; Rapport, Mark D; Kofler, Michael J; Sarver, Dustin E

2012-07-01

Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD-working memory (WM) and behavioral inhibition (BI)-to examine the extent to which ADHD-related impulsive responding was attributable to model-specific mechanisms and processes. Children with ADHD (n = 21) and typically developing children (n = 20) completed laboratory tasks that provided WM (domain-general central executive [CE], phonological/visuospatial storage/rehearsal) and BI indices (stop-signal reaction time [SSRT], stop-signal delay, mean reaction time). These indices were examined as potential mediators of ADHD-related impulsive responding on two objective and diverse laboratory tasks used commonly to assess impulsive responding (CPT: continuous performance test; VMTS: visual match-to-sample). Bias-corrected, bootstrapped mediation analyses revealed that CE processes significantly attenuated between-group impulsivity differences, such that the initial large-magnitude impulsivity differences were no longer significant on either task after accounting for ADHD-related CE deficits. In contrast, SSRT partially mediated ADHD-related impulsive responding on the CPT but not VMTS. This partial attenuation was no longer significant after accounting for shared variance between CE and SSRT; CE continued to attenuate the ADHD-impulsivity relationship after accounting for SSRT. These findings add to the growing literature implicating CE deficits in core ADHD behavioral and functional impairments, and suggest that cognitive interventions targeting CE rather than storage/rehearsal or BI processes may hold greater promise for alleviating ADHD-related impairments.

Influence of High-Current-Density Impulses on the Compression Behavior: Experiments with Iron and a Nickel-Based Alloy

NASA Astrophysics Data System (ADS)

Demler, E.; Gerstein, G.; Dalinger, A.; Epishin, A.; Rodman, D.; Nürnberger, F.

2017-01-01

Difficulties of processing of high strength and/or brittle materials by plastic deformation, e.g., by forging, require to develop new industrial technologies. In particular, the feasible deformation rates are limited for low-ductile metallic materials. For this reason, processes were investigated to improve the deformability in which electrical impulses are to be applied to lower the yield strength. However, owing to the impulse duration and low current densities, concomitant effects always occur, e.g., as a result of Joule heating. Current developments in power electronics allow now to transmit high currents as short pulses. By reducing the impulse duration and increasing the current density, the plasticity of metallic materials can be correspondingly increased. Using the examples of polycrystalline iron and a single-crystal, nickel-based alloy (PWA 1480), current advances in the development of methods for forming materials by means of high-current-density impulses are demonstrated. For this purpose, appropriate specimens were loaded in compression and, using novel testing equipment, subjected to a current strength of 10 kA with an impulse duration of 2 ms. For a pre-defined strain, the test results show a significant decrease in the compressive stress during the compression test and a significant change in the dislocation distribution following the current impulse treatment.

Simulation Analysis of DC and Switching Impulse Superposition Circuit

NASA Astrophysics Data System (ADS)

Zhang, Chenmeng; Xie, Shijun; Zhang, Yu; Mao, Yuxiang

2018-03-01

Surge capacitors running between the natural bus and the ground are affected by DC and impulse superposition voltage during operation in the converter station. This paper analyses the simulation aging circuit of surge capacitors by PSCAD electromagnetic transient simulation software. This paper also analyses the effect of the DC voltage to the waveform of the impulse voltage generation. The effect of coupling capacitor to the test voltage waveform is also studied. Testing results prove that the DC voltage has little effect on the waveform of the output of the surge voltage generator, and the value of the coupling capacitor has little effect on the voltage waveform of the sample. Simulation results show that surge capacitor DC and impulse superimposed aging test is feasible.

Impulsiveness, postprandial blood glucose, and glucoregulation affect measures of behavioral flexibility.

PubMed

Riby, Leigh M; Lai Teik Ong, Derek; Azmie, Nurulnadia Binti Mohamad; Ooi, Ee Lyn; Regina, Caroline; Yeo, Eugene Ki Wai; Massa, Jacqueline; Aquili, Luca

2017-12-01

Behavioral flexibility (BF) performance is influenced by both psychological and physiological factors. Recent evidence suggests that impulsivity and blood glucose can affect executive function, of which BF is a subdomain. Here, we hypothesized that impulsivity, fasting blood glucose (FBG), glucose changes (ie, glucoregulation) from postprandial blood glucose (PBG) following the intake of a 15-g glucose beverage could account for variability in BF performance. The Stroop Color-Word Test and the Wisconsin Card Sorting Test (WCST) were used as measures of BF, and the Barratt Impulsiveness Scale (BIS-11) to quantify participants' impulsivity. In Study 1, neither impulsivity nor FBG could predict performance on the Stroop or the WCST. In Study 2, we tested whether blood glucose levels following the intake of a sugary drink, and absolute changes in glucose levels following the intake of the glucose beverage could better predict BF. Results showed that impulsivity and the difference in blood glucose between time 1 (postprandial) and time 2, but not blood glucose levels at time 2 per se could account for variation in performance on the WCST but not on the Stroop task. More specifically, lower impulsivity scores on the BIS-11, and smaller differences in blood glucose levels from time 1 to time 2 predicted a decrease in the number of total and perseverative errors on the WCST. Our results show that measures of impulsivity and glucoregulation can be used to predict BF. Importantly our data extend the work on glucose and cognition to a clinically relevant domain of cognition. Copyright © 2017 Elsevier Inc. All rights reserved.

Test-retest reliability of behavioral measures of impulsive choice, impulsive action, and inattention.

PubMed

Weafer, Jessica; Baggott, Matthew J; de Wit, Harriet

2013-12-01

Behavioral measures of impulsivity are widely used in substance abuse research, yet relatively little attention has been devoted to establishing their psychometric properties, especially their reliability over repeated administration. The current study examined the test-retest reliability of a battery of standardized behavioral impulsivity tasks, including measures of impulsive choice (i.e., delay discounting, probability discounting, and the Balloon Analogue Risk Task), impulsive action (i.e., the stop signal task, the go/no-go task, and commission errors on the continuous performance task), and inattention (i.e., attention lapses on a simple reaction time task and omission errors on the continuous performance task). Healthy adults (n = 128) performed the battery on two separate occasions. Reliability estimates for the individual tasks ranged from moderate to high, with Pearson correlations within the specific impulsivity domains as follows: impulsive choice (r range: .76-.89, ps < .001); impulsive action (r range: .65-.73, ps < .001); and inattention (r range: .38-.42, ps < .001). Additionally, the influence of day-to-day fluctuations in mood, as measured by the Profile of Mood States, was assessed in relation to variability in performance on each of the behavioral tasks. Change in performance on the delay discounting task was significantly associated with change in positive mood and arousal. No other behavioral measures were significantly associated with mood. In sum, the current analysis demonstrates that behavioral measures of impulsivity are reliable measures and thus can be confidently used to assess various facets of impulsivity as intermediate phenotypes for drug abuse.

Test-retest reliability of behavioral measures of impulsive choice, impulsive action, and inattention

PubMed Central

Weafer, Jessica; Baggott, Matthew J.; de Wit, Harriet

2014-01-01

Behavioral measures of impulsivity are widely used in substance abuse research, yet relatively little attention has been devoted to establishing their psychometric properties, especially their reliability over repeated administration. The current study examined the test-retest reliability of a battery of standardized behavioral impulsivity tasks, including measures of impulsive choice (delay discounting, probability discounting, and the Balloon Analogue Risk Task), impulsive action (the stop signal task, the go/no-go task, and commission errors on the continuous performance task), and inattention (attention lapses on a simple reaction time task and omission errors on the continuous performance task). Healthy adults (n=128) performed the battery on two separate occasions. Reliability estimates for the individual tasks ranged from moderate to high, with Pearson correlations within the specific impulsivity domains as follows: impulsive choice (r = .76 - .89, ps < .001); impulsive action (r = .65 - .73, ps < .001); and inattention (r = .38-.42, ps < .001). Additionally, the influence of day-to-day fluctuations in mood as measured by the Profile of Mood States was assessed in relation to variability in performance on each of the behavioral tasks. Change in performance on the delay discounting task was significantly associated with change in positive mood and arousal. No other behavioral measures were significantly associated with mood. In sum, the current analysis demonstrates that behavioral measures of impulsivity are reliable measures and thus can be confidently used to assess various facets of impulsivity as intermediate phenotypes for drug abuse. PMID:24099351

Narcissism predicts impulsive buying: phenotypic and genetic evidence

PubMed Central

Cai, Huajian; Shi, Yuanyuan; Fang, Xiang; Luo, Yu L. L.

2015-01-01

Impulsive buying makes billions of dollars for retail businesses every year, particularly in an era of thriving e-commerce. Narcissism, characterized by impulsivity and materialism, may serve as a potential antecedent to impulsive buying. To test this hypothesis, two studies examined the relationship between narcissism and impulsive buying. In Study 1, we surveyed an online sample and found that while adaptive narcissism was not correlated with impulsive buying, maladaptive narcissism was significantly predictive of the impulsive buying tendency. By investigating 304 twin pairs, Study 2 showed that global narcissism and its two components, adaptive and maladaptive narcissism, as well as the impulsive buying tendency were heritable. The study found, moreover, that the connections between global narcissism and impulsive buying, and between maladaptive narcissism and impulsive buying were genetically based. These findings not only establish a link between narcissism and impulsive buying but also help to identify the origins of the link. The present studies deepen our understanding of narcissism, impulsive buying, and their interrelationship. PMID:26217251

Narcissism predicts impulsive buying: phenotypic and genetic evidence.

PubMed

Cai, Huajian; Shi, Yuanyuan; Fang, Xiang; Luo, Yu L L

2015-01-01

Impulsive buying makes billions of dollars for retail businesses every year, particularly in an era of thriving e-commerce. Narcissism, characterized by impulsivity and materialism, may serve as a potential antecedent to impulsive buying. To test this hypothesis, two studies examined the relationship between narcissism and impulsive buying. In Study 1, we surveyed an online sample and found that while adaptive narcissism was not correlated with impulsive buying, maladaptive narcissism was significantly predictive of the impulsive buying tendency. By investigating 304 twin pairs, Study 2 showed that global narcissism and its two components, adaptive and maladaptive narcissism, as well as the impulsive buying tendency were heritable. The study found, moreover, that the connections between global narcissism and impulsive buying, and between maladaptive narcissism and impulsive buying were genetically based. These findings not only establish a link between narcissism and impulsive buying but also help to identify the origins of the link. The present studies deepen our understanding of narcissism, impulsive buying, and their interrelationship.

Implications of different methods for specifying classroom composition of externalizing behavior and its relationship to social–emotional outcomes

PubMed Central

Yudron, Monica; Jones, Stephanie M.; Raver, C. Cybele

2016-01-01

In this paper, we examine common methods for using individual-level data to represent classroom composition by examining exemplary studies that thoughtfully incorporate such measures. Building on these studies, and using data from the Chicago School Readiness Project (CSRP), this paper examines theoretical and analytical implications of a set of different transformations of individual ratings of child externalizing behaviors in order to examine and compare the influence of these representations of classroom composition on Kindergarten internalizing behaviors, social competence, and attention/impulsivity problems. Results indicate that each Kindergarten outcome is influenced by distinct aspects of classroom composition of externalizing behaviors. Kindergarten internalizing behaviors are positively associated with the proportion of children in the Head Start classroom who started with externalizing scores above the 75th percentile regardless of the average value of externalizing behaviors in the classroom. In contrast, Kindergarten social competence is predicted by three aspects of the classroom distribution of externalizing behaviors in the fall of Head Start—the classroom mean, standard deviation, and skew. Finally, Kindergarten attention/impulsivity problems were not associated with any aspect of classroom composition of externalizing behavior examined in this paper. PMID:28275289

Objectively-Measured Impulsivity and Attention-Deficit/Hyperactivity Disorder (ADHD): Testing Competing Predictions from the Working Memory and Behavioral Inhibition Models of ADHD

ERIC Educational Resources Information Center

Raiker, Joseph S.; Rapport, Mark D.; Kofler, Michael J.; Sarver, Dustin E.

2012-01-01

Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD--working memory (WM)…

Cognitive correlates in panic disorder as related to impulsivity - preliminary report.

PubMed

Jakuszkowiak-Wojten, Katarzyna; Gałuszko-Węgielnik, Maria; Raczak, Alicja; Cubała, Wiesław Jerzy; Wiglusz, Mariusz Stanisław; Herstowska, Marta; Landowski, Jerzy

2012-09-01

Impulsivity is the neurophysiologically based inability to confirm behaviour to its context or consequences. Overimpulsiveness characterizes many mental disorders and poses an important clinical dilemma. Although the relationship between mood disorders and impulsivity has been well studied the relationship between anxiety and impulsivity is controversial and not well explored. Some studies hypothesise that patients with the diagnosis of panic disorders are characterised by higher levels of impulsivity as a trait as compared to healthy individuals. The aim of this study was to assess cognitive correlates in panic disorder as related to impulsivity measures. Within the preliminary studies four patients diagnosed with panic disorder (DSM-IV-TR) were studied. The severity measure was the Panic and Agoraphobia Scale. The experimental group comprised of psychotropic drug naive patients. Impulsiveness was evaluated with the Barrat Impulsiveness Scale - 11th version (BIS-11). To asses cognitive functions we used CANTAB (Cambridge Neuropsychological Test Automated Battery). BIS-11 scores observed in the group of psychotropic drug naive patients with panic disorder were higher than the adjusted average for the population and correlated with the number of mistakes in CANTAB (Spatial Working Memory Test); rs=0.949; p=0.0513. The preliminary findings indicate a correlation between impulsivity and cognitive deficits in panic disorder in psychotropic drug naive patients.

Characterization of the non axial thrust generated by large solid propellant rocket motors in three axis stabilized ascent

NASA Technical Reports Server (NTRS)

Kosmann, W. J.; Dionne, E. R.; Klemetson, R. W.

1978-01-01

Nonaxial thrusts produced by solid rocket motors during three-axis stabilized attitude control have been determined from ascent experience on twenty three Burner II, Burner IIA and Block 5D-1 upper stage vehicles. A data base representing four different rocket motor designs (three spherical and one extended spherical) totaling twenty five three-axis stabilized firings is generated. Solid rocket motor time-varying resultant and lateral side force vector magnitudes, directions and total impulses, and roll torque couple magnitudes, directions, and total impulses are tabulated in the appendix. Population means and three sigma deviations are plotted. Existing applicable ground test side force and roll torque magnitudes and total impulses are evaluated and compared to the above experience data base. Within the spherical motor population, the selected AEDC ground test data consistently underestimated experienced motor side forces, roll torques and total impulses. Within the extended spherical motor population, the selected AEDC test data predicted experienced motor side forces, roll torques, and total impulses, with surprising accuracy considering the very small size of the test and experience populations.

A Triadic Reflective-Impulsive-Interoceptive Awareness Model of General and Impulsive Information System Use: Behavioral Tests of Neuro-Cognitive Theory

PubMed Central

Turel, Ofir; Bechara, Antoine

2016-01-01

This study examines a behavioral tripartite model developed in the field of addiction, and applies it here to understanding general and impulsive information technology use. It suggests that technology use is driven by two information-processing brain systems: reflective and impulsive, and that their effects on use are modulated by interoceptive awareness processes. The resultant reflective-impulsive-interoceptive awareness model is tested in two behavioral studies. Both studies employ SEM techniques to time-lagged self-report data from n1 = 300 and n2 = 369 social networking site users. Study 1 demonstrated that temptations augment the effect of habit on technology use, and reduce the effect of satisfaction on use. Study 2 showed that temptations strengthen the effect of habit on impulsive technology use, and weaken the effect of behavioral expectations on impulsive technology use. Hence, the results consistently support the notion that information technology users' behaviors are influenced by reflective and impulsive information processing systems; and that the equilibrium of these systems is determined, at least in part, by one's temptations. These results can serve as a basis for understanding the etiology of modern day addictions. PMID:27199834

A Triadic Reflective-Impulsive-Interoceptive Awareness Model of General and Impulsive Information System Use: Behavioral Tests of Neuro-Cognitive Theory.

PubMed

Turel, Ofir; Bechara, Antoine

2016-01-01

This study examines a behavioral tripartite model developed in the field of addiction, and applies it here to understanding general and impulsive information technology use. It suggests that technology use is driven by two information-processing brain systems: reflective and impulsive, and that their effects on use are modulated by interoceptive awareness processes. The resultant reflective-impulsive-interoceptive awareness model is tested in two behavioral studies. Both studies employ SEM techniques to time-lagged self-report data from n 1 = 300 and n 2 = 369 social networking site users. Study 1 demonstrated that temptations augment the effect of habit on technology use, and reduce the effect of satisfaction on use. Study 2 showed that temptations strengthen the effect of habit on impulsive technology use, and weaken the effect of behavioral expectations on impulsive technology use. Hence, the results consistently support the notion that information technology users' behaviors are influenced by reflective and impulsive information processing systems; and that the equilibrium of these systems is determined, at least in part, by one's temptations. These results can serve as a basis for understanding the etiology of modern day addictions.

Study on the streamer inception characteristics under positive lightning impulse voltage

NASA Astrophysics Data System (ADS)

Wang, Zezhong; Geng, Yinan

2017-11-01

The streamer is the main process in an air gap discharge, and the inception characteristics of streamers have been widely applied in engineering. Streamer inception characteristics under DC voltage have been studied by many researchers, but the inception characteristics under impulse voltage, and particularly under lightning impulse voltage with a high voltage rise rate have rarely been studied. A measurement system based on integrated optoelectronic technology has been proposed in this paper, and the streamer inception characteristics in a 1-m-long rod-plane air gap that was energized by a positive lightning impulse voltage have been researched. We have also measured the streamer inception electric field using electrodes with different radii of curvature and different voltage rise rates. As a result, a modified empirical criterion for the streamer inception electric field that considers the voltage rise rate has been proposed, and the wide applicability of this criterion has been proved. Based on the streamer inception time-lag obtained, we determined that the field distribution obeys a Rayleigh distribution, which explains the change law of the streamer inception time-lag. The characteristic parameter of the Rayleigh distribution lies in the range from 0.6 to 2.5 when the radius of curvature of the electrode head is in the range from 0.5 cm to 2.5 cm and the voltage rise rate ranges from 80 kV/μs to 240kV/μs under positive lightning impulse voltage.

Development and automation of a test of impulse control in zebrafish

PubMed Central

Parker, Matthew O.; Ife, Dennis; Ma, Jun; Pancholi, Mahesh; Smeraldi, Fabrizio; Straw, Chris; Brennan, Caroline H.

2013-01-01

Deficits in impulse control (difficulties in inhibition of a pre-potent response) are fundamental to a number of psychiatric disorders, but the molecular and cellular basis is poorly understood. Zebrafish offer a very useful model for exploring these mechanisms, but there is currently a lack of validated procedures for measuring impulsivity in fish. In mammals, impulsivity can be measured by examining rates of anticipatory responding in the 5-choice serial reaction time task (5-CSRTT), a continuous performance task where the subject is reinforced upon accurate detection of a briefly presented light in one of five distinct spatial locations. This paper describes the development of a fully-integrated automated system for testing impulsivity in adult zebrafish. We outline the development of our image analysis software and its integration with National Instruments drivers and actuators to produce the system. We also describe an initial validation of the system through a one-generation screen of chemically mutagenized zebrafish, where the testing parameters were optimized. PMID:24133417

Increased impulsivity associated with severity of suicide attempt history in patients with bipolar disorder.

PubMed

Swann, Alan C; Dougherty, Donald M; Pazzaglia, Peggy J; Pham, Mary; Steinberg, Joel L; Moeller, F Gerard

2005-09-01

Impulsivity is a prominent and measurable characteristic of bipolar disorder that can contribute to risk for suicidal behavior. The purpose of this study was to investigate the relationship between impulsivity and severity of past suicidal behavior, a potential predictor of eventual suicide, in patients with bipolar disorder. In bipolar disorder subjects with either a definite history of attempted suicide or no such history, impulsivity was assessed with both a questionnaire (Barratt Impulsiveness Scale) and behavioral laboratory performance measures (immediate memory/delayed memory tasks). Diagnosis was determined with the Structured Clinical Interview for DSM-IV. Interviews of patients and review of records were used to determine the number of past suicide attempts and the medical severity of the most severe attempt. Subjects with a history of suicide attempts had more impulsive errors on the immediate memory task and had shorter response latencies, especially for impulsive responses. Impulsivity was highest in subjects with the most medically severe suicide attempts. Effects were not accounted for by presence of depression or mania at the time of testing. Barratt Impulsiveness Scale scores were numerically, but not significantly, higher in subjects with suicide attempts. A history of alcohol abuse was associated with greater probability of a suicide attempt. Multivariate analysis showed that ethanol abuse history and clinical state at the time of testing did not have a significant effect after impulsivity was taken into account. These results suggest that a history of severe suicidal behavior in patients with bipolar disorder is associated with impulsivity, manifested as a tendency toward rapid, unplanned responses.

Serotonin Depletion Induces ‘Waiting Impulsivity' on the Human Four-Choice Serial Reaction Time Task: Cross-Species Translational Significance

PubMed Central

Worbe, Yulia; Savulich, George; Voon, Valerie; Fernandez-Egea, Emilio; Robbins, Trevor W

2014-01-01

Convergent results from animal and human studies suggest that reducing serotonin neurotransmission promotes impulsive behavior. Here, serotonin depletion was induced by the dietary tryptophan depletion procedure (TD) in healthy volunteers to examine the role of serotonin in impulsive action and impulsive choice. We used a novel translational analog of a rodent 5-choice serial reaction time task (5-CSRTT)— the human 4-CSRTT—and a reward delay-discounting questionnaire to measure effects on these different forms of ‘waiting impulsivity'. There was no effect of TD on impulsive choice as indexed by the reward delay-discounting questionnaire. However, TD significantly increased 4-CSRTT premature responses (or impulsive action), which is remarkably similar to the previous findings of effect of serotonin depletion on rodent 5-CSRTT performance. Moreover, the increased premature responding in TD correlated significantly with individual differences on the motor impulsivity subscale of the Barratt Impulsivity Scale. TD also improved the accuracy of performance and speeded responding, possibly indicating enhanced attention and reward processing. The results suggest: (i) the 4-CSRTT will be a valuable addition to the tests already available to measure impulsivity in humans in a direct translational analog of a test extensively used in rodents; (ii) TD in humans produces a qualitatively similar profile of effects to those in rodents (ie, enhancing premature responding), hence supporting the conclusion that TD in humans exerts at least some of its effects on central serotonin; and (iii) this manipulation of serotonin produces dissociable effects on different measures of impulsivity, suggesting considerable specificity in its modulatory role. PMID:24385133

Measurement of Impulsive Thrust from a Closed Radio Frequency Cavity in Vacuum

NASA Technical Reports Server (NTRS)

White, Harold; March, Paul; Lawrence, James; Vera, Jerry; Sylvester, Andre; Brady, David; Bailey, Paul

2016-01-01

A vacuum test campaign evaluating the impulsive thrust performance of a tapered RF test article excited in the TM212 mode at 1,937 megahertz (MHz) has been completed. The test campaign consisted of a forward thrust phase and reverse thrust phase at less than 8 x 10(exp -6) Torr vacuum with power scans at 40 watts, 60 watts, and 80 watts. The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified. Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 mN/kW.

Evidence for a dysfunctional prefrontal circuit in patients with an impulsive aggressive disorder

PubMed Central

Best, Mary; Williams, J. Michael; Coccaro, Emil F.

2002-01-01

Humans with lesions to the orbital/medial prefrontal cortex and interconnected areas display impulsive aggressive behavior. To examine further the relationship between impulsive aggression and orbital/medial prefrontal dysfunction, we measured the behavioral performance of psychiatric patients with a disorder characterized by impulsive aggression, Intermittent Explosive Disorder (IED). Presently, no evidence exists for a localized brain lesion in IED subjects. However, on the basis of the location of brain lesions that produce acquired impulsive aggression, we hypothesized that IED subjects would exhibit test performance similar to patients with lesions to the orbital/medial prefrontal cortex. Subjects with IED and controls were administered three tests sensitive to lesions of the orbital/medial prefrontal circuit: the Iowa Gambling Task, facial emotion recognition, and odor identification, and two control tests of working memory. On the gambling task, IED subjects continued to make disadvantageous decisions throughout the 100 trials, whereas controls learned to avoid disadvantageous decisions. On the facial recognition test, IED subjects were impaired at recognizing “anger,” “disgust,” and “surprise,” and they were biased to label neutral faces with “disgust” and “fear.” On odor identification, IED subjects were mildly anosmic and were impaired relative to controls. However, on the working memory control tests, both groups performed similarly. Across tests, the performance of IED subjects resembles the performance of patients with orbital/medial prefrontal lesions in previous studies. These results extend the link between dysfunction of the orbital/medial prefrontal circuit and impulsive aggressive behavior. PMID:12034876

Measurement of impulse peak insertion loss for four hearing protection devices in field conditions

PubMed Central

Murphy, William J.; Flamme, Gregory A.; Meinke, Deanna K.; Sondergaard, Jacob; Finan, Donald S.; Lankford, James E.; Khan, Amir; Vernon, Julia; Stewart, Michael

2015-01-01

Objective In 2009, the U.S. Environmental Protection Agency (EPA) proposed an impulse noise reduction rating (NRR) for hearing protection devices based upon the impulse peak insertion loss (IPIL) methods in the ANSI S12.42-2010 standard. This study tests the ANSI S12.42 methods with a range of hearing protection devices measured in field conditions. Design The method utilizes an acoustic test fixture and three ranges for impulse levels: 130–134, 148–152, and 166–170 dB peak SPL. For this study, four different models of hearing protectors were tested: Bilsom 707 Impact II electronic earmuff, E·A·R Pod Express, E·A·R Combat Arms version 4, and the Etymotic Research, Inc. Electronic BlastPLG™ EB1. Study sample Five samples of each protector were fitted on the fixture or inserted in the fixture's ear canal five times for each impulse level. Impulses were generated by a 0.223 caliber rifle. Results The average IPILs increased with peak pressure and ranged between 20 and 38 dB. For some protectors, significant differences were observed across protector examples of the same model, and across insertions. Conclusions The EPA's proposed methods provide consistent and reproducible results. The proposed impulse NRR rating should utilize the minimum and maximum protection percentiles as determined by the ANSI S12.42-2010 methods. PMID:22176308

Conscientiousness and (un)healthy eating: the role of impulsive eating and age in the consumption of daily main meals.

PubMed

Olsen, Svein Ottar; Tuu, Ho Huy; Honkanen, Pirjo; Verplanken, Bas

2015-08-01

The present study aims to explore the relationship between conscientiousness and the consumption of healthy versus unhealthy main meals. Impulsive eating was tested as a mediator in this relationship, as well as direct effects of age on those constructs. A nationwide representative sample of 1,006 Norwegian adults (18-70 years) within a prospective design was used to test a theoretical model. The structural equation model (SEM), in combination with bootstrapping procedures in AMOS, was the principal analytical method. Conscientiousness was negatively associated with unhealthy and impulsive eating. Impulsive eating was a partial mediator between conscientiousness and unhealthy eating and a full mediator between conscientiousness and healthy eating. Age was positively correlated with conscientiousness and this relationship had an inverted U-shape form. Finally, age was negatively associated with unhealthy and impulsive eating, and positively associated with healthy eating. This study confirmed the relevance of conscientiousness for healthy, unhealthy, and impulsive eating. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Minnesota Impulse Disorders Interview (MIDI): Validation of a structured diagnostic clinical interview for impulse control disorders in an enriched community sample.

PubMed

Chamberlain, Samuel R; Grant, Jon E

2018-07-01

Disorders of impulsivity are common, functionally impairing, and highly relevant across different clinical and research settings. Few structured clinical interviews for the identification and diagnosis of impulse control disorders exist, and none have been validated in a community sample in terms of psychometric properties. The Minnesota Impulse control disorders Interview (MIDI v2.0) was administered to an enriched sample of 293 non-treatment seeking adults aged 18-35 years, recruited using media advertisements in two large US cities. In addition to the MIDI, participants undertook extended clinical interview for other mental disorders, the Barratt impulsiveness questionnaire, and the Padua obsessive-compulsive inventory. The psychometric properties of the MIDI were characterized. In logistic regression, the MIDI showed good concurrent validity against the reference measures (versus gambling disorder interview, p < 0.001; Barratt impulsiveness attentional and non-planning scores p < 0.05), and good discriminant validity versus primarily non-impulsive symptoms, including against anxiety, depression, and obsessive-compulsive symptoms (all p > 0.05). Test re-test reliability was excellent (0.95). The MIDI has good psychometric properties and thus may be a valuable interview tool for clinical and research studies involving impulse control disorders. Further research is needed to better understanding the optimal diagnostic classification and neurobiology of these neglected disorders. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

The moving minimum audible angle is smaller during self motion than during source motion

PubMed Central

Brimijoin, W. Owen; Akeroyd, Michael A.

2014-01-01

We are rarely perfectly still: our heads rotate in three axes and move in three dimensions, constantly varying the spectral and binaural cues at the ear drums. In spite of this motion, static sound sources in the world are typically perceived as stable objects. This argues that the auditory system—in a manner not unlike the vestibulo-ocular reflex—works to compensate for self motion and stabilize our sensory representation of the world. We tested a prediction arising from this postulate: that self motion should be processed more accurately than source motion. We used an infrared motion tracking system to measure head angle, and real-time interpolation of head related impulse responses to create “head-stabilized” signals that appeared to remain fixed in space as the head turned. After being presented with pairs of simultaneous signals consisting of a man and a woman speaking a snippet of speech, normal and hearing impaired listeners were asked to report whether the female voice was to the left or the right of the male voice. In this way we measured the moving minimum audible angle (MMAA). This measurement was made while listeners were asked to turn their heads back and forth between ± 15° and the signals were stabilized in space. After this “self-motion” condition we measured MMAA in a second “source-motion” condition when listeners remained still and the virtual locations of the signals were moved using the trajectories from the first condition. For both normal and hearing impaired listeners, we found that the MMAA for signals moving relative to the head was ~1–2° smaller when the movement was the result of self motion than when it was the result of source motion, even though the motion with respect to the head was identical. These results as well as the results of past experiments suggest that spatial processing involves an ongoing and highly accurate comparison of spatial acoustic cues with self-motion cues. PMID:25228856

Sex differences in dimensions of impulsivity in a non-clinical sample.

PubMed

Lage, Guilherme Menezes; Albuquerque, Maicon Rodrigues; Fuentes, Daniel; Corrêa, Humberto; Malloy-Diniz, Leandro Fernandes

2013-10-01

Impulsivity has been more closely associated with men than with women because men are more often involved in illegal behaviors. The few studies that have investigated sex differences in impulsivity have used self-report questionnaires and have obtained contradictory results. Two computerized behavioral tests were administered to 125 healthy undergraduate students (75 women, M age 23.8 yr.; 50 men, M age 25.0 yr.). Men exhibited higher scores on motor impulsivity, but there were no significant differences between men and women on attentional and non-planning impulsivity scores. These findings are discussed in terms of the relationship between impulsivity and low- and high-order control.

Nervus terminalis in dogfish (Squalus acanthias, Elasmobranchii) carries tonic efferent impulses.

PubMed

Bullock, T H; Northcutt, R G

1984-02-10

Recordings from the intact nervus terminalis with a hook electrode or from a stump of the divided nerve with a suction electrode show a tonic, irregular discharge of broad, low frequency spikes in ca. 4-6 units. These nerve impulses are efferent from the brain. The mean frequency of discharge is not influenced by various chemical, thermal, tactile, acoustic, photic, vibratory and electric field stimuli but is decreased by certain forms of mechanical stimuli, presumably acting on the lateral line organs of the lateral aspect of the head. We have not succeeded in recording from afferents. The nerve consists of greater than 1000 unmyelinated axons, mostly less than 1 micron, a very few greater than 1.5 micron in diameter; presumably the efferents recorded from were these larger fibers.

Association between the Catechol O-Methyltransferase (COMT) Val158met Polymorphism and Different Dimensions of Impulsivity

PubMed Central

Malloy-Diniz, Leandro Fernandes; Lage, Guilherme Menezes; Campos, Simone Becho; de Paula, Jonas Jardim; de Souza Costa, Danielle; Romano-Silva, Marco Aurélio; de Miranda, Débora Marques; Correa, Humberto

2013-01-01

Background Impulsivity is a multidimensional construct which has been associated with dopaminergic neurotransmission. Nonetheless, until this moment, few studies addressed the relationship between different types of impulsivity and the single nucleotide polymorphism caused by a substitution of valine (val) with methionine (met) in the 158 codon of the Catechol-o-Methyltransferase gene (COMT-val158met). The present study aimed to investigate the association between val158met COMT polymorphism and impulsive behavior measured by two neuropsychological tests. Methodology/Principal Findings We administered two neuropsychological tests, a Continuous Performance Task and the Iowa Gambling Task were applied to 195 healthy participants to characterize their levels of motor, attentional and non-planning impulsivity. Then, subjects were grouped by genotype, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional and motor impulsivity. Those participants who were homozygous for the met allele performed worse in the Iowa Gambling Task than val/val and val/met subjects. Conclusions/Significance Our results suggest that met allele of val158met COMT polymorphism is associated with poor performance in decision-making/cognitive impulsivity task. The results reinforce the hypothesis that val and met alleles of the val158met polymorphism show functional dissociation and are related to different prefrontal processes. PMID:24039968

Genetic and Modeling Approaches Reveal Distinct Components of Impulsive Behavior

PubMed Central

Nautiyal, Katherine M; Wall, Melanie M; Wang, Shuai; Magalong, Valerie M; Ahmari, Susanne E; Balsam, Peter D; Blanco, Carlos; Hen, René

2017-01-01

Impulsivity is an endophenotype found in many psychiatric disorders including substance use disorders, pathological gambling, and attention deficit hyperactivity disorder. Two behavioral features often considered in impulsive behavior are behavioral inhibition (impulsive action) and delayed gratification (impulsive choice). However, the extent to which these behavioral constructs represent distinct facets of behavior with discrete biological bases is unclear. To test the hypothesis that impulsive action and impulsive choice represent statistically independent behavioral constructs in mice, we collected behavioral measures of impulsivity in a single cohort of mice using well-validated operant behavioral paradigms. Mice with manipulation of serotonin 1B receptor (5-HT1BR) expression were included as a model of disordered impulsivity. A factor analysis was used to characterize correlations between the measures of impulsivity and to identify covariates. Using two approaches, we dissociated impulsive action from impulsive choice. First, the absence of 5-HT1BRs caused increased impulsive action, but not impulsive choice. Second, based on an exploratory factor analysis, a two-factor model described the data well, with measures of impulsive action and choice separating into two independent factors. A multiple-indicator multiple-causes analysis showed that 5-HT1BR expression and sex were significant covariates of impulsivity. Males displayed increased impulsivity in both dimensions, whereas 5-HT1BR expression was a predictor of increased impulsive action only. These data support the conclusion that impulsive action and impulsive choice are distinct behavioral phenotypes with dissociable biological influences that can be modeled in mice. Our work may help inform better classification, diagnosis, and treatment of psychiatric disorders, which present with disordered impulsivity. PMID:27976680

30 CFR 27.32 - Tests to determine performance of the system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... gallery. To comply with the requirements of this test, the detector shall provide an impulse to actuate an alarm at a predetermined percentage of gas and also provide an impulse to actuate a power shutoff at a...

30 CFR 27.32 - Tests to determine performance of the system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... gallery. To comply with the requirements of this test, the detector shall provide an impulse to actuate an alarm at a predetermined percentage of gas and also provide an impulse to actuate a power shutoff at a...

30 CFR 27.32 - Tests to determine performance of the system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... gallery. To comply with the requirements of this test, the detector shall provide an impulse to actuate an alarm at a predetermined percentage of gas and also provide an impulse to actuate a power shutoff at a...

30 CFR 27.32 - Tests to determine performance of the system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... gallery. To comply with the requirements of this test, the detector shall provide an impulse to actuate an alarm at a predetermined percentage of gas and also provide an impulse to actuate a power shutoff at a...

Gender Differences in University EFL Students' Language Proficiency Corresponding to Self-Rated Attention, Hyperactivity and Impulsivity

ERIC Educational Resources Information Center

Liang, Hsin-Yi; Kelsen, Brent A.

2017-01-01

Introduction: This study examines university students' self-reported inattention, hyperactivity and impulsivity, and their relation to performance on a high-stakes English proficiency test while taking gender into consideration. Method: Inattention, hyperactivity and impulsivity attributes were assessed using the Adult Attention…

Investigation of Blade Impulsive Noise on a Scaled Fully Articulated Rotor System

NASA Technical Reports Server (NTRS)

Scheiman, James; Hoad, Danny R.

1977-01-01

Helicopter impulsive noise tests were conducted in the Langley V/STOL tunnel with an articulated rotor system. The tests demonstrated that impulsive noise could be simulated for low-speed forward flight with low descent rates and also in the high-speed level flight. For the low forward speed condition, the noise level was highly sensitive to small changes in descent rate. For the high-speed condition, the noise level was increased with an increase in rotor thrust.

The Effects of Aging on Clinical Vestibular Evaluations

PubMed Central

Maheu, Maxime; Houde, Marie-Soleil; Landry, Simon P.; Champoux, François

2015-01-01

Balance disorders are common issues for aging populations due to the effects of normal aging on peripheral vestibular structures. These changes affect the results of vestibular function evaluations and make the interpretation of these results more difficult. The objective of this article is to review the current state of knowledge of clinically relevant vestibular measures. We will first focus on otolith function assessment methods cervical-VEMP (cVEMP) and ocular-VEMP (oVEMP), then the caloric and video-head impulse test (vHIT) methods for semicircular canals assessment. cVEMP and oVEMP are useful methods, though research on the effects of age for some parameters are still inconclusive. vHIT results are largely independent of age as compared to caloric stimulation and should therefore be preferred for the evaluation of the semicircular canals function. PMID:26441824

Norepinephrine and impulsivity: Effects of acute yohimbine

PubMed Central

Swann, Alan C.; Lijffijt, Marijn; Lane, Scott D.; Cox, Blake; Steinberg, Joel L.; Moeller, F. Gerard

2013-01-01

Rationale Rapid-response impulsivity, characterized by inability to withhold response to a stimulus until it is adequately appraised, is associated with risky behavior and may be increased in a state-dependent manner by norepinephrine. Objective We assessed effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on plasma catecholamine metabolites, blood pressure, subjective symptoms, and laboratory-measured rapid-response impulsivity. Methods Subjects were twenty-three healthy controls recruited from the community, with normal physical examination and ECG, and negative history for hypertension, cardiovascular illness, and Axis I or II disorder. Blood pressure, pulse, and behavioral measures were obtained before and periodically after 0.4 mg/kg oral yohimbine or placebo in a randomized, counterbalanced design. Metabolites of norepinephrine (3-methoxy-4-hydroxyphenylglycol, MHPG; vanillylmandelic acid, VMA) and dopamine (homovanillic acid, HVA) were measured by high pressure liquid chromatography with electrochemical detection. Rapid-response impulsivity was measured by commission errors and reaction times on the Immediate Memory Task (IMT), a continuous performance test designed to measure impulsivity and attention. Results Yohimbine increased plasma MHPG and VMA but not HVA. Yohimbine increased systolic and diastolic blood pressure and pulse rate. On the IMT, yohimbine increased impulsive errors and impulsive response bias and accelerated reaction times. Yohimbine-associated increase in plasma MHPG correlated with increased impulsive response rates. Time courses varied; effects on blood pressure generally preceded those on metabolites and test performance. Conclusions These effects are consistent with increased rapid-response impulsivity after pharmacological noradrenergic stimulation in healthy controls. Labile noradrenergic responses, or increased sensitivity to norepinephrine, may increase risk for impulsive behavior. PMID:23559222

[Testing a Model to Predict Problem Gambling in Speculative Game Users].

PubMed

Park, Hyangjin; Kim, Suk Sun

2018-04-01

The purpose of the study was to develop and test a model for predicting problem gambling in speculative game users based on Blaszczynski and Nower's pathways model of problem and pathological gambling. The participants were 262 speculative game users recruited from seven speculative gambling places located in Seoul, Gangwon, and Gyeonggi, Korea. They completed a structured self-report questionnaire comprising measures of problem gambling, negative emotions, attentional impulsivity, motor impulsivity, non-planning impulsivity, gambler's fallacy, and gambling self-efficacy. Structural Equation Modeling was used to test the hypothesized model and to examine the direct and indirect effects on problem gambling in speculative game users using SPSS 22.0 and AMOS 20.0 programs. The hypothetical research model provided a reasonable fit to the data. Negative emotions, motor impulsivity, gambler's fallacy, and gambling self-efficacy had direct effects on problem gambling in speculative game users, while indirect effects were reported for negative emotions, motor impulsivity, and gambler's fallacy. These predictors explained 75.2% problem gambling in speculative game users. The findings suggest that developing intervention programs to reduce negative emotions, motor impulsivity, and gambler's fallacy, and to increase gambling self-efficacy in speculative game users are needed to prevent their problem gambling. © 2018 Korean Society of Nursing Science.

TNT equivalency of M10 propellant

NASA Technical Reports Server (NTRS)

Mcintyre, F. L.; Price, P.

1978-01-01

Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration.

Thrust augmentation nozzle (TAN) concept for rocket engine booster applications

NASA Astrophysics Data System (ADS)

Forde, Scott; Bulman, Mel; Neill, Todd

2006-07-01

Aerojet used the patented thrust augmented nozzle (TAN) concept to validate a unique means of increasing sea-level thrust in a liquid rocket booster engine. We have used knowledge gained from hypersonic Scramjet research to inject propellants into the supersonic region of the rocket engine nozzle to significantly increase sea-level thrust without significantly impacting specific impulse. The TAN concept overcomes conventional engine limitations by injecting propellants and combusting in an annular region in the divergent section of the nozzle. This injection of propellants at moderate pressures allows for obtaining high thrust at takeoff without overexpansion thrust losses. The main chamber is operated at a constant pressure while maintaining a constant head rise and flow rate of the main propellant pumps. Recent hot-fire tests have validated the design approach and thrust augmentation ratios. Calculations of nozzle performance and wall pressures were made using computational fluid dynamics analyses with and without thrust augmentation flow, resulting in good agreement between calculated and measured quantities including augmentation thrust. This paper describes the TAN concept, the test setup, test results, and calculation results.

Theophylline effects on cognition, behavior, and learning.

PubMed

Weldon, D P; McGeady, S J

1995-01-01

To compare a group of hospitalized asthmatic children taking theophylline with a similar group of hospitalized nonasthmatic children on standardized measures of distractibility, attention, hyperactivity, and academic achievement. Standardized psychological tests were used to measure cognition, attention, and learning, and results for the two groups were compared. All subjects were hospitalized in an intermediate care facility. Up to 63 asthmatic children taking theophylline were compared with a group of 46 nonasthmatic children matched for age, sex, socioeconomic status, and full-scale IQ. Children with head injuries, mental retardation, or known learning disabilities were not included. All asthmatic children and none of the nonasthmatic children maintained therapeutic levels of theophylline during the evaluation period. Independent t tests were used to examine differences between groups on psychological tests of cognition, attention, and learning. No significant differences were found between groups on any variables at the 95% level of confidence. While idiosyncratic side effects of theophylline are possible, most children are not more hyperactive, distractible, short of memory, different in academic achievement, or more impulsive than other children with chronic illness.

Effect of amplitude and duration of impulsive pressure on endothelial permeability in in vitro fluid percussion trauma

PubMed Central

2014-01-01

Background Intracranial pressure changes during head impact cause brain injuries such as vasogenic edema and cerebral contusion. However, the influence of impulsive pressure on endothelial function has not yet been fully studied in vitro. In this study, we developed a pressure loading device that produced positive and negative pressures by modifying an in vitro fluid percussion model and examined the effects of the amplitude and duration of the pressures on endothelial permeability. Methods Human umbilical vein endothelial cells were subjected to three types of positive pressure (average amplitude/average duration of 352 kPa/23 ms, 73 kPa/27 ms, and 70 kPa/44 ms) and three types of negative pressure (−72 kPa/41 ms, −67 kPa/104 ms, and −91 kPa/108 ms), and the transendothelial electrical resistance (TEER) was measured between 15 min and 24 h after pressure loading for quantifying the formation of an integral monolayer of endothelial cells. After loading, vascular endothelial- (VE-) cadherin, an endothelium-specific cell-cell adhesion molecule involved in endothelial barrier function, was stained and observed using fluorescence microscopy. Results The pressure loading device could produce positive pressure pulses with amplitudes of 53–1348 kPa and durations of 9–29.1 ms and negative pressure pulses with amplitudes of −52–−93 kPa and durations of 42.9–179.5 ms. The impulsive pressure reduced the TEER associated with the change in VE-cadherin localization. Additionally, TEER decreased considerably at 15 min and 6 h post-loading, with these changes being significant in positive pressure with larger amplitude and shorter duration and in all types of negative pressures compared to pre-loading. Conclusions The changes in intracranial pressure during head impact impair endothelial barrier function by the disruption of the integrity of endothelial cell-cell junctions, and the degree of increase in endothelial permeability depends on the amplitude, duration, and direction (compressive and tensile) of the impulsive pressure. PMID:24739360

The Moderating Effect of Social Support on the Relationship Between Impulsivity and Suicide in Rural China.

PubMed

Zhang, Jie; Lin, Lin

2015-07-01

This study was to investigate the relationship among social support, impulsivity, and suicide, so as to test the hypothesis that social support moderates the effect of impulsivity on suicide for the rural young suicides in China. Subjects were 392 consecutively recruited suicides aged 15-34 years and 416 community controls of the same age range sampled in China. The case-control data were obtained using psychological autopsy. The results showed that high social support had the protective effect among individuals with low impulsivity. It can be concluded that impulsivity is a potential area for further study of suicidal behavior. The suicide prevention efforts in rural China may address impulsivity.

The Effect of Implicit Preferences on Food Consumption: Moderating Role of Ego Depletion and Impulsivity

PubMed Central

Wang, Yan; Zhu, Jinglei; Hu, Yi; Fang, Yuan; Wang, Guosen; Cui, Xianghua; Wang, Lei

2016-01-01

Ego depletion has been found to moderate the effect of implicit preferences on food consumption, such that implicit preferences predict consumption only under a depleted state. The present study tested how trait impulsivity impacts the effect of implicit preferences on food consumption in a depleted condition. Trait impulsivity was measured by means of self-report and a stop signal task. Results showed that both self-reported impulsivity and behavioral impulsivity moderated the ‘depletion and then eating according to implicit preferences’ effect, albeit in different ways. Participants high in self-reported impulsivity and low in behavioral impulsivity were more vulnerable to the effect of depletion on eating. The implications of these results for extant theories are discussed. Future research is needed to verify whether or not trait impulsivity is associated with vulnerability to depletion across different self-control domains. PMID:27881966

Impulsivity in self-mutilative behavior: psychometric and biological findings.

PubMed

Herpertz, S; Sass, H; Favazza, A

1997-01-01

This paper examines impulsivity as a central factor in moderate/superficial self-mutilation such as skin-cutting and burning. A sample of 165 subjects were divided into four groups, namely self-mutilators, patients with any modes of impulsive behavior other than self-mutilation, patients without any impulsive behavior, and normal probands. All were administered the 10th version of the Barratt Impulsiveness Scale, the State-Trait Anger Expression Inventory, and the Inventory for the Assessment of Factors of Aggressiveness. They also were interviewed carefully in regards to both impulsive and self-mutilative behavior. A d-fenfluramine challenge test was administered to 36 females and prolactin levels were measured. On the whole results implicate impulsive personality functioning as a major factor in subjects with moderate/superficial self-mutilative behavior whose trait pathology is similar to personality disordered patients with other modes of self-harming impulsive behavior.

Compression of head-related transfer function using autoregressive-moving-average models and Legendre polynomials.

PubMed

Shekarchi, Sayedali; Hallam, John; Christensen-Dalsgaard, Jakob

2013-11-01

Head-related transfer functions (HRTFs) are generally large datasets, which can be an important constraint for embedded real-time applications. A method is proposed here to reduce redundancy and compress the datasets. In this method, HRTFs are first compressed by conversion into autoregressive-moving-average (ARMA) filters whose coefficients are calculated using Prony's method. Such filters are specified by a few coefficients which can generate the full head-related impulse responses (HRIRs). Next, Legendre polynomials (LPs) are used to compress the ARMA filter coefficients. LPs are derived on the sphere and form an orthonormal basis set for spherical functions. Higher-order LPs capture increasingly fine spatial details. The number of LPs needed to represent an HRTF, therefore, is indicative of its spatial complexity. The results indicate that compression ratios can exceed 98% while maintaining a spectral error of less than 4 dB in the recovered HRTFs.

Reflectiveness/Impulsiveness and Mathematics Achievement

ERIC Educational Resources Information Center

Cathcart, W. George; Liedtke, Werner

1969-01-01

Report of research to test the hypothesis that reflective students would be higher achievers in mathematics than impulsive pupils. An achievement test was developed to measure understanding of mathematical concepts and applications, ability to solve verbal problems and recall basic facts. Data suggest that reflective students obtain better…

On the limits of Kagan's impulsive reflective distinction.

PubMed

Jones, B; McIntyre, L

1976-05-01

A logical analysis is made of the Matching Familiar Figures (MFF) Test on the basis of which children have been classified as "impulsive" or "reflective." The reflective strategy is implicitly preferred to the impulsive because the reflective child makes fewer errors though generally taking longer to make his first response. We show that the test allows the choice of a number of "game plans" and speed-accuracy tradeoffs which in practice may not be very different. Error rates may not indicate perceptual sensitivity, in any case, since sensitivity and response factors may be confounded in the error rate. Using a visual running-memory-span task to avoid the inherent difficulties of the MFF test, we found that children previously classified on the basis of that test as impulsive or reflective did not differ in recognition accuracy but did differ in response bias and response latency. Accuracy and bias are estimated by way of Luce's choice theory (Luce, 1963), and the results are discussed in those terms.

Exposure to impulse noise at an explosives company: a case study.

PubMed

Kulik, Aleksandra; Malinowska-Borowska, Jolanta

2018-02-15

Impulse noise encountered in workplaces is a threat to hearing. The aim of this study was to assess the occupational exposure to impulse noise produced by detonation of dynamite on the premises of an explosives company. Test points were located on the blast test area (inside and outside the bunker) and in work buildings across the site. Noise propagation measurement was performed during 130 blast tests at nine measurement points. At every point, at least 10 separate measurements of A-weighted equivalent sound pressure level (L A eq ), maximum A-weighted sound pressure level (L A max ) and C-weighted peak sound pressure level (L C peak ) were made. Noise recorded in the blast test area exceeded occupational exposure limits (OELs). Noise levels measured in buildings did not exceed OELs. Results of the survey showed that for 62% of respondents, impulse noise causes difficulties in performing work. The most commonly reported symptoms include headaches, nervousness and irritability.

Examining impulsivity as a moderator of the relationship between body shame and bulimic symptoms in Black and White young women.

PubMed

Higgins, M K; Lin, Stacy L; Alvarez, Alexandra; Bardone-Cone, Anna M

2015-06-01

Impulsivity has been linked to bulimic symptomatology in a number of studies; however, few have examined this relationship among Black women. We investigated the correlations between impulsivity and bulimic symptoms, and tested impulsivity as a moderator of the body shame/bulimic symptoms relationship among a sample of female undergraduates (N=276; 97 Blacks, 179 Whites). These participants provided data on body shame, impulsivity, and bulimic symptoms (EDE-Q binge eating frequency, BULIT-R, EDI-Bulimia). Among Blacks, impulsivity was significantly positively associated with all bulimic symptoms measures; among Whites, impulsivity was only positively correlated with binge eating frequency. Furthermore, among Blacks, the combination of high body shame and high impulsivity was associated with the highest levels of bulimic symptoms; these findings were not observed among Whites. This study highlights the importance of impulsivity and body shame in identifying bulimic symptomatology among Black women. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impulsivity, Coping, Stress, and Problem Gambling among University Students

ERIC Educational Resources Information Center

Lightsey, Owen Richard, Jr.; Hulsey, C. Duncan

2002-01-01

The authors investigated whether coping styles moderated the relationship between (a) impulsivity and stress and (b) stress and gambling behavior and tested whether impulsive persons who use avoidant or emotion-focused coping under high-stress conditions are most likely to gamble. Among 202 university student volunteers, 33% of men but only 3% of…

D4 receptor deficiency in mice has limited effects on impulsivity and novelty seeking.

PubMed

Helms, C M; Gubner, N R; Wilhelm, C J; Mitchell, S H; Grandy, D K

2008-09-01

Alleles of the human dopamine D(4) receptor (D(4)R) gene (DRD4.7) have repeatedly been found to correlate with novelty seeking, substance abuse, pathological gambling, and attention-deficit hyperactivity disorder (ADHD). If these various psychopathologies are a result of attenuated D(4)R-mediated signaling, mice lacking D(4)Rs (D(4)KO) should be more impulsive than wild-type (WT) mice and exhibit more novelty seeking. However, in our study, D(4)KO and WT mice showed similar levels of impulsivity as measured by delay discounting performance and response inhibition on a Go/No-go test, suggesting that D(4)R-mediated signaling may not affect impulsivity. D(4)KO mice were more active than WT mice in the first 5 min of a novel open field test, suggesting greater novelty seeking. For both genotypes, more impulsive mice habituated less in the novel open field. These data suggest that the absence of D(4)Rs is not sufficient to cause psychopathologies associated with heightened impulsivity and novelty seeking.

Trait impulsivity predicts D-KEFS tower test performance in university students.

PubMed

Lyvers, Michael; Basch, Vanessa; Duff, Helen; Edwards, Mark S

2015-01-01

The present study examined a widely used self-report index of trait impulsiveness in relation to performance on a well-known neuropsychological executive function test in 70 university undergraduate students (50 women, 20 men) aged 18 to 24 years old. Participants completed the Barratt Impulsiveness Scale (BIS-11) and the Frontal Systems Behavior Scale (FrSBe), after which they performed the Tower Test of the Delis-Kaplan Executive Function System. Hierarchical linear regression showed that after controlling for gender, current alcohol consumption, age at onset of weekly alcohol use, and FrSBe scores, BIS-11 significantly predicted Tower Test Achievement scores, β = -.44, p < .01. The results indicate that self-reported impulsiveness is associated with poorer executive cognitive performance even in a sample likely to be characterized by relatively high general cognitive functioning (i.e., university students). The results also support the role of inhibition as a key aspect of executive task performance. Elevated scores on the BIS-11 and FrSBe are known to be linked to risky drinking in young adults as confirmed in this sample; however, only BIS-11 predicted Tower Test performance.

Trait impulsivity is associated with the risk of falls in Parkinson's disease.

PubMed

Smulders, Katrijn; Esselink, Rianne A; Cools, Roshan; Bloem, Bastiaan R

2014-01-01

Impulsivity is a "tendency to act prematurely without foresight." Clinical experience suggests that such impulsive behavior can impact on the fall risk in Parkinson's disease (PD), but this has never been tested. We investigated whether trait impulsivity is related to fall risk in a large cohort of PD patients. We also investigated whether trait impulsivity affects the fall risk differently for patients with more or less postural instability and gait disability (PIGD). 388 patients with PD (H&Y ≤ 3) completed the Barratt Impulsiveness Scale (BIS-11, higher scores indicating greater impulsivity) to assess trait impulsivity, including three subscales: motor impulsivity (e.g. "I do things without thinking"), attentional impulsivity (e.g. "I concentrate easily") and non-planning (e.g. "I plan tasks carefully"). Falls were registered prospectively for 6 months. Patients classified as non-fallers (0 falls, n = 237) were compared to recurrent PD fallers (>1 fall, n = 78). Total impulsivity scores were higher for recurrent fallers (59.5) compared to non-fallers (56.8; p = .012). This effect was predominantly driven by higher scores on the subscale for attentional impulsivity (p = .003). The difference in attentional impulsivity was independent of gender, disease severity, dopaminergic medication, and cognitive function. Motor and non-planning impulsivity did not differ between recurrent fallers and non-fallers. There was no evidence that impulsivity modulated the association between PIGD and fall risk. This is the first evidence that impulsivity, in particular in the attentional domain, is related to fall risk in PD.

The Air Force Phillips Laboratory multimegawatt quasi-steady MPD thruster facility

NASA Astrophysics Data System (ADS)

Castillo, Salvador; Tilley, Dennis L.

1992-07-01

The operational multimegawatt quasi-steady MPD thruster facility is described in terms of its general design emphasizing the impulse thrust stand and diagnostics capabilities. The vacuum, propellant, and electrical systems are discussed with schematic diagrams of the respective component configurations and explanations of the needs of MPD thruster testing. The impulse thrust stand comprises an accelerometer/pendulum-impulse stand which can be used to correlate thruster impulse with accelerometer readings and thereby reduce measurement uncertainties. The diagnostics of the terminal characteristics of the thruster operation are complemented by diagnostics platforms that study plasma properties in the plume and the thruster. Preliminary tests indicate that the MPD thruster facility is prepared for detailed investigations of MPD thruster performance and plume diagnostics.

Influence of impulsivity-reflexivity when testing dynamic spatial ability: sex and g differences.

PubMed

Quiroga, M Angeles; Hernández, José Manuel; Rubio, Victor; Shih, Pei Chun; Santacreu, José

2007-11-01

This work analyzes the possibility that the differences in the performance of men and women in dynamic spatial tasks such as the Spatial Orientation Dynamic Test-Revised (SODT-R; Santacreu & Rubio, 1998), obtained in previous works, are due to cognitive style (Reflexivity-Impulsivity) or to the speed-accuracy tradeoff (SATO) that the participants implement. If these differences are due to cognitive style, they would be independent of intelligence, whereas if they are due to SATO, they may be associated with intelligence. In this work, 1652 participants, 984 men and 668 women, ages between 18 and 55 years, were assessed. In addition to the SODT-R, the "Test de Razonamiento Analitico, Secuencial e Inductivo" (TRASI [Analytical, Sequential, and Inductive Reasoning Test]; Rubio & Santacreu, 2003) was administered as a measure of general intelligence. Impulsivity scores (Zi) of Salkind and Wright (1977) were used to analyze reflexivity-impulsivity and SATO. The results obtained indicate that (a) four performance groups can be identified: Fast-accurate, Slow-inaccurate, Impulsive, and Reflexive. The first two groups solve the task as a function of a competence variable and the last two as a function of a personality variable; (b) performance differences should be attributed to SATO; (c) SATO differs depending on sex and intelligence level.

The role of attention problems and impulsiveness in media violence effects on aggression.

PubMed

Swing, Edward L; Anderson, Craig A

2014-01-01

Previous research has established media violence as a causal risk factor for aggressive behavior. Several theoretical mechanisms have been identified to explain this effect. The present study assessed 422 undergraduate students to test the possibility that individual differences in attention problems and impulsiveness can help explain the link between violent media and aggression. Attention problems and impulsiveness proved to be a distinct construct from other processes believed to mediate aggression (aggressive beliefs, aggression related schemata, trait anger, and trait hostility). Attention problems and impulsiveness were uniquely related to both media exposure (total weekly hours and violent content) and aggression. Attention problems and impulsiveness were particularly related to impulsive (as opposed to premeditated) aggression. These results suggest that attention problems and impulsiveness may play an important role in violent media effects on aggression. © 2014 Wiley Periodicals, Inc.

Development and evaluation of the impulse transfer function technique

NASA Technical Reports Server (NTRS)

Mantus, M.

1972-01-01

The development of the test/analysis technique known as the impulse transfer function (ITF) method is discussed. This technique, when implemented with proper data processing systems, should become a valuable supplement to conventional dynamic testing and analysis procedures that will be used in the space shuttle development program. The method can relieve many of the problems associated with extensive and costly testing of the shuttle for transient loading conditions. In addition, the time history information derived from impulse testing has the potential for being used to determine modal data for the structure under investigation. The technique could be very useful in determining the time-varying modal characteristics of structures subjected to thermal transients, where conventional mode surveys are difficult to perform.

Optimal neurocognitive, personality and behavioral measures for assessing impulsivity in cocaine dependence.

PubMed

LoBue, Christian; Cullum, C Munro; Braud, Jacqueline; Walker, Robrina; Winhusen, Theresa; Suderajan, Prabha; Adinoff, Bryon

2014-11-01

Impulsivity may underlie the poor treatment retention and high relapse rates observed in cocaine-dependent persons. However, observed differences in measures of impulsivity between cocaine-dependent and healthy control participants often do not reach clinical significance, suggesting that the clinical relevance of these differences may be limited. To examine which measures of impulsivity (i.e. self-report impulsivity, self-report personality, neurocognitive testing) best distinguish cocaine-dependent and healthy control participants (i.e. showing differences at least 1.5 standard deviations [SD] from controls). Optimal measures were considered to demonstrate sufficient classification accuracy. Sixty-five recently abstinent cocaine-dependent and 25 healthy control participants were assessed using select neurocognitive tests and self-report questionnaires including the NEO Personality Inventory-Revised (NEO-PI-R), Temperament and Character Inventory (TCI), Barratt Impulsiveness Scale (BIS-11a), and the Frontal Systems Behavior Scale (FrSBe). When corrected for years of education and gender, neurocognitive measures did not demonstrate clinically significant differences between cocaine-dependent and control participants. The personality measures TCI Purposefulness and Congruent Second Nature and NEO-PI-R Impulsiveness, and the self-rating measures FrSBe Disinhibition and BIS-11 Motor Impulsivity and Total successfully identified clinically meaningful elevations in impulsivity within cocaine-dependent participants (>1.5 SDs from controls). Furthermore, these measures achieved 84-93% accuracy in discriminating cocaine-dependent from control participants. Clinically significant neurocognitive impairment in cocaine-dependent participants was not observed in this sample. As the BIS-11 or FrSBe are brief to administer, accurate, and have been shown to predict treatment retention and relapse, these measures appear to be optimal, relative to the personality measures, for examining trait impulsivity in cocaine dependence.

High Trait Impulsivity Predicts Food Addiction-Like Behavior in the Rat

PubMed Central

Velázquez-Sánchez, Clara; Ferragud, Antonio; Moore, Catherine F; Everitt, Barry J; Sabino, Valentina; Cottone, Pietro

2014-01-01

Impulsivity is a behavioral trait frequently seen not only in drug-addicted individuals but also in individuals who pathologically overeat. However, whether impulsivity predates the development of uncontrollable feeding is unknown. In this study, we hypothesized that a high impulsivity trait precedes and confers vulnerability for food addiction-like behavior. For this purpose, we trained ad libitum-fed male Wistar rats in a differential reinforcement of low rates of responding (DRL) task to select Low- and High-impulsive rats. Then, we allowed Low- and High-impulsive rats to self-administer a highly palatable diet (Palatable group) or a regular chow diet (Chow group) in 1-h daily sessions, under fixed ratio (FR) 1, FR3, FR5, and under a progressive ratio (PR) schedules of reinforcement. In addition, we tested the compulsiveness for food in Low- and High-impulsive rats by measuring the food eaten in the aversive, open compartment of a light/dark conflict test. Finally, we measured the expression of the transcription factor ΔFosB in the shell and the core of the nucleus accumbens, which is a marker for neuroadaptive changes following addictive drug exposure. The data we obtained demonstrate that impulsivity is a trait that predicts the development of food addiction-like behaviors, including: (i) excessive intake, (ii) heightened motivation for food, and (iii) compulsive-like eating, when rats are given access to highly palatable food. In addition, we show that the food addiction phenotype in high impulsive subjects is characterized by an increased expression of the transcription factor ΔFosB in the nucleus accumbens shell. These results reveal that impulsivity confers an increased propensity to develop uncontrollable overeating of palatable food. PMID:24776685

High trait impulsivity predicts food addiction-like behavior in the rat.

PubMed

Velázquez-Sánchez, Clara; Ferragud, Antonio; Moore, Catherine F; Everitt, Barry J; Sabino, Valentina; Cottone, Pietro

2014-09-01

Impulsivity is a behavioral trait frequently seen not only in drug-addicted individuals but also in individuals who pathologically overeat. However, whether impulsivity predates the development of uncontrollable feeding is unknown. In this study, we hypothesized that a high impulsivity trait precedes and confers vulnerability for food addiction-like behavior. For this purpose, we trained ad libitum-fed male Wistar rats in a differential reinforcement of low rates of responding (DRL) task to select Low- and High-impulsive rats. Then, we allowed Low- and High-impulsive rats to self-administer a highly palatable diet (Palatable group) or a regular chow diet (Chow group) in 1-h daily sessions, under fixed ratio (FR) 1, FR3, FR5, and under a progressive ratio (PR) schedules of reinforcement. In addition, we tested the compulsiveness for food in Low- and High-impulsive rats by measuring the food eaten in the aversive, open compartment of a light/dark conflict test. Finally, we measured the expression of the transcription factor ΔFosB in the shell and the core of the nucleus accumbens, which is a marker for neuroadaptive changes following addictive drug exposure. The data we obtained demonstrate that impulsivity is a trait that predicts the development of food addiction-like behaviors, including: (i) excessive intake, (ii) heightened motivation for food, and (iii) compulsive-like eating, when rats are given access to highly palatable food. In addition, we show that the food addiction phenotype in high impulsive subjects is characterized by an increased expression of the transcription factor ΔFosB in the nucleus accumbens shell. These results reveal that impulsivity confers an increased propensity to develop uncontrollable overeating of palatable food.

Optimal neurocognitive, personality and behavioral measures for assessing impulsivity in cocaine dependence

PubMed Central

LoBue, Christian; Cullum, C. Munro; Braud, Jacqueline; Walker, Robrina; Winhusen, Theresa; Suderajan, Prabha; Adinoff, Bryon

2015-01-01

Background Impulsivity may underlie the poor treatment retention and high relapse rates observed in cocaine-dependent persons. However, observed differences in measures of impulsivity between cocaine-dependent and healthy control participants often do not reach clinical significance, suggesting that the clinical relevance of these differences may be limited. Objectives To examine which measures of impulsivity (i.e. self-report impulsivity, self-report personality, neurocognitive testing) best distinguish cocaine-dependent and healthy control participants (i.e. showing differences at least 1.5 standard deviations [SD] from controls). Optimal measures were considered to demonstrate sufficient classification accuracy. Methods Sixty-five recently abstinent cocaine-dependent and 25 healthy control participants were assessed using select neurocognitive tests and self-report questionnaires including the NEO Personality Inventory-Revised (NEO-PI-R), Temperament and Character Inventory (TCI), Barratt Impulsiveness Scale (BIS-11a), and the Frontal Systems Behavior Scale (FrSBe). Results When corrected for years of education and gender, neurocognitive measures did not demonstrate clinically significant differences between cocaine-dependent and control participants. The personality measures TCI Purposefulness and Congruent Second Nature and NEO-PI-R Impulsiveness, and the self-rating measures FrSBe Disinhibition and BIS-11 Motor Impulsivity and Total successfully identified clinically meaningful elevations in impulsivity within cocaine-dependent participants (>1.5 SDs from controls). Furthermore, these measures achieved 84–93% accuracy in discriminating cocaine-dependent from control participants. Conclusion Clinically significant neurocognitive impairment in cocaine-dependent participants was not observed in this sample. As the BIS-11 or FrSBe are brief to administer, accurate, and have been shown to predict treatment retention and relapse, these measures appear to be optimal, relative to the personality measures, for examining trait impulsivity in cocaine dependence. PMID:25083938

Intracranial Pressure Response to Non-Penetrating Ballistic Impact: An Experimental Study Using a Pig Physical Head Model and Live Pigs

PubMed Central

Liu, Hai; Kang, Jianyi; Chen, Jing; Li, Guanhua; Li, Xiaoxia; Wang, Jianmin

2012-01-01

This study was conducted to characterize the intracranial pressure response to non-penetrating ballistic impact using a "scalp-skull-brain" pig physical head model and live pigs. Forty-eight ballistic tests targeting the physical head model and anesthetized pigs protected by aramid plates were conducted with standard 9 mm bullets at low (279-297 m/s), moderate (350-372 m/s), and high (409-436 m/s) velocities. Intracranial pressure responses were recorded with pressure sensors embedded in similar brain locations in the physical head model and the anesthetized pigs. Three parameters of intracranial pressure were determined from the measured data: intracranial maximum pressure (Pmax), intracranial maximum pressure impulse (PImax), and the duration of the first positive phase (PPD). The intracranial pressure waves exhibited blast-like characteristics for both the physical model and l live pigs. Of all three parameters, Pmax is most sensitive to impact velocity, with means of 126 kPa (219 kPa), 178 kPa (474 kPa), and 241 kPa (751 kPa) for the physical model (live pigs) for low, moderate, and high impact velocities, respectively. The mean PPD becomes increasingly short as the impact velocity increases, whereas PImax shows the opposite trend. Although the pressure parameters of the physical model were much lower than those of the live pigs, good correlations between the physical model and the live pigs for the three pressure parameters, especially Pmax, were found using linear regression. This investigation suggests that Pmax is a preferred parameter for predicting the severity of the brain injury resulting from behind armor blunt trauma (BABT). PMID:23055817

Behavioral measures and self-report of impulsivity in bipolar disorder: no association between Stroop test and Barratt Impulsiveness Scale.

PubMed

Strasser, Elisa Sophie; Haffner, Paula; Fiebig, Jana; Quinlivan, Esther; Adli, Mazda; Stamm, Thomas Josef

2016-12-01

Impulsivity as a tendency to act quickly without considering future consequences has been proposed as a dimensional factor in bipolar disorder. It can be measured using behavioral tasks and self-report questionnaires. Previous findings revealed patients to show worse performance on at least one behavioral measure of impulsivity. Additionally, self-reported impulsivity seems to be higher among bipolar patients, both parameters being possibly associated with a more severe course of illness. In this study, our primary aim was to investigate the relationship between these two constructs of impulsivity among bipolar patients. A total of 40 euthymic patients with bipolar disorder (21 female, 22 Bipolar I) and 30 healthy controls were recruited for comprehensive neuropsychological assessment. To assess inhibition control as a behavioral measure of impulsivity, the Stroop Color and Word Test (Stroop) was used. Additionally, both groups completed the Barratt Impulsiveness Scale (BIS) as a self-report of impulsivity. To compare the groups' performance on the Stroop and ratings on the BIS, the non-parametric Mann-Whitney U test was used. Within the bipolar group, we additionally examined the possibility of an association between Stroop performance and BIS total scores using Pearson's Correlation r. Patients and controls differed significantly on the Stroop and BIS, with patients performing worse on the Stroop and scoring higher on the BIS. However, there was no association between the Stroop and BIS within the bipolar group. As an exploratory analysis, a positive correlation between Stroop performance and number of episodes was found. Further, we detected a statistical trend in the direction of poorer Stroop performance among patients treated with polypharmacy. Both difficulties with behavioral inhibition and self-reported impulsivity were observed to be higher in bipolar patients than controls in the current study. However, within the patient group we did not observe an association between patients' behavioral performance and self-report. This indicates that the parameters likely constitute distinct, dimensional factors of bipolar disorder. In future research, studies with larger samples should investigate which of the two markers constitutes the better marker for the illness and is more suitable to differentiate the most severe patients.

Persistent effects of chronic Δ9-THC exposure on motor impulsivity in rats.

PubMed

Irimia, Cristina; Polis, Ilham Y; Stouffer, David; Parsons, Loren H

2015-08-01

In humans, long-term marijuana use is associated with impaired impulse control and attentional capacity, though it has been difficult to distinguish pre-existing cognitive deficits from possible consequences of prolonged marijuana exposure. To evaluate the effects of long-term exposure to Δ9-Tetrahydrocannabinol (Δ9-THC), the primary psychoactive constituent in marijuana, on indices of impulse control and attentional capacity using the rat 5-Choice Serial Reaction Time Task (5-CSRTT). Ten 14-day cycles of Δ9-THC dosing and 5-CSRTT testing were employed, each comprised of 5-day Δ9-THC dosing (0.3 or 3 mg/kg b.i.d.) and 5-CSRTT testing during the 9 days of drug abstinence. Subsequent 5-CSRTT testing continued during 5 weeks of protracted abstinence. Dose-dependent increases in motor impulsivity (premature responses) and behavioral disinhibition (perseverative responses) emerged following 5 cycles of Δ9-THC exposure that persisted for the remaining dosing and testing cycles. Δ9-THC-related disruptions in motor impulsivity and behavioral inhibition were most pronounced during cognitively challenging 5-CSRTT sessions incorporating varying novel inter-trial intervals (ITIs), and these disruptions persisted for at least 5 weeks of Δ9-THC abstinence. Δ9-THC-related impairments in attentional capacity (response accuracy) were also evident during variable ITI challenge tests, though these attentional disruptions abated within 3 weeks of Δ9-THC abstinence. These observations demonstrate that long-term intermittent exposure to clinically meaningful Δ9-THC doses induces persistent impairments in impulse control and attentional function. If present in humans, these disruptions may impact academic and professional performance.

Effortful Control and Impulsivity as Concurrent and Longitudinal Predictors of Academic Achievement

ERIC Educational Resources Information Center

Valiente, Carlos; Eisenberg, Nancy; Spinrad, Tracy L.; Haugen, Rg; Thompson, Marilyn S.; Kupfer, Anne

2013-01-01

The goal of this study was to test if both effortful control (EC) and impulsivity, a reactive index of temperament, uniquely predict adolescents' academic achievement, concurrently and longitudinally (Time 1: "N" = 168, X-bar[subscript age] = 12 years). At Time 1, parents and teachers reported on students' EC and impulsivity.…

Timing of head movements is consistent with energy minimization in walking ungulates

PubMed Central

Loscher, David M.; Meyer, Fiete; Kracht, Kerstin

2016-01-01

Many ungulates show a conspicuous nodding motion of the head when walking. Until now, the functional significance of this behaviour remained unclear. Combining in vivo kinematics of quadrupedal mammals with a computer model, we show that the timing of vertical displacements of the head and neck is consistent with minimizing energy expenditure for carrying these body parts in an inverted pendulum walking gait. Varying the timing of head movements in the model resulted in increased metabolic cost estimate for carrying the head and neck of up to 63%. Oscillations of the head–neck unit result in weight force oscillations transmitted to the forelimbs. Advantageous timing increases the load in single support phases, in which redirecting the trajectory of the centre of mass (COM) is thought to be energetically inexpensive. During double support, in which—according to collision mechanics—directional changes of the impulse of the COM are expensive, the observed timing decreases the load. Because the head and neck comprise approximately 10% of body mass, the effect shown here should also affect the animals' overall energy expenditure. This mechanism, working analogously in high-tech backpacks for energy-saving load carriage, is widespread in ungulates, and provides insight into how animals economize locomotion. PMID:27903873

Impulsivity and suicidality: the mediating role of painful and provocative experiences.

PubMed

Bender, Theodore W; Gordon, Kathryn H; Bresin, Konrad; Joiner, Thomas E

2011-03-01

Multiple studies have reported a link between high levels of impulsivity and suicidal behavior. Joiner's (2005) explanation for this link is that impulsive individuals have a greater tendency to experience painful and provocative events that habituate them to fear and pain, which leads to an acquired capability for engaging in suicidal behavior. Study 1 tested Joiner's (2005) hypothesis in a sample of 182 undergraduate students who completed self-report questionnaires on impulsivity, frequency of painful and provocative events, and acquired capability for suicide. In addition to self-report, pain tolerance (an aspect of acquired capability for suicide) was measured with a pressure algometer. Study 2 sought to replicate our findings from Study 1 in a sample of 516 clinical outpatients using a multi-faceted measure of impulsivity. Consistent with prediction, product of coefficients tests for mediation (MacKinnon et al., 2002) revealed that impulsivity has an indirect relationship with acquired capability for suicidal behavior, and that this relationship is mediated by painful and provocative events. Data from our studies are cross-sectional in nature, which does not allow for conclusions about the temporal ordering of our variables. In addition, self-report was used to measure most variables. Future research may benefit from a longitudinal design and the inclusion of other modes of assessment (e.g., behavioral measures of impulsivity). Our findings suggest that the link between impulsivity and suicidal behavior occurs because impulsive people tend to have a greater capability for suicidal behavior, which they have acquired through experiencing painful and provocative events. Copyright © 2010 Elsevier B.V. All rights reserved.

Diet-induced impulsivity: Effects of a high-fat and a high-sugar diet on impulsive choice in rats

PubMed Central

Pirkle, Jesseca R. A.; Kirkpatrick, Kimberly

2017-01-01

Impulsive choice is a common charactertistic among individuals with gambling problems, obesity, and substance abuse issues. Impulsive choice has been classified as a trans-disease process, and understanding the etiology of trait impulsivity could help to understand how diseases and disorders related to impulsive choice are manifested. The Western diet is a possible catalyst of impulsive choice as individuals who are obese and who eat diets high in fat and sugar are typically more impulsive. However, such correlational evidence is unable to discern the direction and causal nature of the relationship. The present study sought to determine how diet may directly contribute to impulsive choice. After 8 weeks of dietary exposure (high-fat, high-sugar, chow), the rats were tested on an impulsive choice task, which presented choices between a smaller-sooner reward (SS) and a larger-later reward (LL). Then, the rats were transferred to a chow diet and retested on the impulsive choice task. The high-sugar and high-fat groups made significantly more impulsive choices than the chow group. Both groups became more self-controlled when they were off the diet, but there were some residual effects of the diet on choice behavior. These results suggest that diet, specifically one high in processed fat or sugar, induces impulsive choice. This diet-induced impulsivity could be a precursor to other disorders that are characterized by impulsivity, such as diet-induced obesity, and could offer potential understanding of the trans-disease nature of impulsive choice. PMID:28662133

Diet-induced impulsivity: Effects of a high-fat and a high-sugar diet on impulsive choice in rats.

PubMed

Steele, Catherine C; Pirkle, Jesseca R A; Kirkpatrick, Kimberly

2017-01-01

Impulsive choice is a common charactertistic among individuals with gambling problems, obesity, and substance abuse issues. Impulsive choice has been classified as a trans-disease process, and understanding the etiology of trait impulsivity could help to understand how diseases and disorders related to impulsive choice are manifested. The Western diet is a possible catalyst of impulsive choice as individuals who are obese and who eat diets high in fat and sugar are typically more impulsive. However, such correlational evidence is unable to discern the direction and causal nature of the relationship. The present study sought to determine how diet may directly contribute to impulsive choice. After 8 weeks of dietary exposure (high-fat, high-sugar, chow), the rats were tested on an impulsive choice task, which presented choices between a smaller-sooner reward (SS) and a larger-later reward (LL). Then, the rats were transferred to a chow diet and retested on the impulsive choice task. The high-sugar and high-fat groups made significantly more impulsive choices than the chow group. Both groups became more self-controlled when they were off the diet, but there were some residual effects of the diet on choice behavior. These results suggest that diet, specifically one high in processed fat or sugar, induces impulsive choice. This diet-induced impulsivity could be a precursor to other disorders that are characterized by impulsivity, such as diet-induced obesity, and could offer potential understanding of the trans-disease nature of impulsive choice.

Individual differences in impulsive action and dopamine transporter function in rat orbitofrontal cortex.

PubMed

Yates, J R; Darna, M; Beckmann, J S; Dwoskin, L P; Bardo, M T

2016-01-28

Impulsivity, which can be subdivided into impulsive action and impulsive choice, is implicated as a factor underlying drug abuse vulnerability. Although previous research has shown that dopamine (DA) systems in prefrontal cortex are involved in impulsivity and substance abuse, it is not known if inherent variation in DA transporter (DAT) function contributes to impulsivity. The current study determined if individual differences in either impulsive action or impulsive choice are related to DAT function in orbitofrontal (OFC) and/or medial prefrontal cortex (mPFC). Rats were first tested both for impulsive action in a cued go/no-go task and for impulsive choice in a delay-discounting task. Following behavioral evaluation, in vitro [(3)H]DA uptake assays were performed in OFC and mPFC isolated from individual rats. Vmax in OFC, but not mPFC, was correlated with performance in the cued go/no-go task, with decreased OFC DAT function being associated with high impulsive action. In contrast, Vmax in OFC and mPFC was not correlated with performance in the delay-discounting task. The current results demonstrate that impulsive behavior in cued go/no-go performance is associated with decreased DAT function in OFC, suggesting that hyperdopaminergic tone in this prefrontal subregion mediates, at least in part, increased impulsive action. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Recovery of Vestibulo-Ocular Reflex Symmetry After an Acute Unilateral Peripheral Vestibular Deficit: Time Course and Correlation With Canal Paresis.

PubMed

Allum, John H J; Cleworth, T; Honegger, Flurin

2016-07-01

We investigated how response asymmetries and deficit side response amplitudes for head accelerations used clinically to test the vestibular ocular reflex (VOR) are correlated with caloric canal paresis (CP) values. 30 patients were examined at onset of an acute unilateral peripheral vestibular deficit (aUPVD) and 3, 6, and 13 weeks later with three different VOR tests: caloric, rotating chair (ROT), and video head impulse tests (vHIT). Response changes over time were fitted with an exponential decay model and compared with using linear regression analysis. Recovery times (to within 10% of steady state) were similar for vHIT-asymmetry and CP (>10 weeks) but shorter for ROT asymmetry (<4 weeks). Regressions with CP were similar (vHIT asymmetry, R = 0.68, ROT, R = 0.62). Responses to the deficit side were also equally well correlated with CP values (R = 0.71). Specificity for vHIT and 20 degrees/s ROT deficit side responses was 100% in comparison to CP values, sensitivity was 74% for vHIT, 75% for ROT. A decrease in normal side responses occurred for ROT but not for vHIT at 3 weeks. Normal side responses were weekly correlated with CP for ROT (R = 0.49) but not for vHIT (R = 0.17). These results indicate that vHIT deficit side VOR gains are slightly better correlated with CP values than ROT, probably because of similar recovery time courses of vHIT and caloric responses and the lack of normal side vHIT changes. However, specificity and sensitivity is the same for vHIT and ROT tests.

Gentamicin ototoxicity: a 23-year selected case series of 103 patients.

PubMed

Ahmed, Rebekah M; Hannigan, Imelda P; MacDougall, Hamish G; Chan, Raymond C; Halmagyi, G Michael

2012-06-18

To review patients with severe bilateral vestibular loss associated with gentamicin treatment in hospital. A retrospective case series of presentations to a balance disorders clinic between 1988 and 2010. Relationship between vestibulotoxicity and gentamicin dose or dosing profile; indications for prescribing gentamicin. 103 patients (age, 18-84 years; mean, 64 years) presented with imbalance, oscillopsia or both, but none had vertigo. Only three noted some hearing impairment after having gentamicin, but audiometric thresholds for all patients were consistent with their age. In all patients, the following tests gave positive results: a bilateral clinical head-impulse test, a vertical head-shaking test for vertical oscillopsia, and a foam Romberg test. In 21 patients, imbalance occurred during gentamicin treatment (ignored or dismissed by prescribers in 20) and in 66 after treatment; the remaining 16 could not recall when symptoms were first noticed, except that it was after gentamicin treatment in hospital. Total gentamicin dose range was 2-318 mg/kg (mean, 52 mg/kg), daily dose range was 1.5-5.6 mg/kg (mean, 3.5mg/kg), and duration was 1-80 days (mean, 17 days). Six patients had only a single dose; 26 had five or fewer doses. Serum gentamicin levels, measured in 82 patients, were in the recommended range in 59. Time to diagnosis ranged from 4 days to 15 years. Nephrotoxicity developed in 43 patients. Gentamicin dosage complied with contemporary or current Australian antibiotic guidelines in under half the patients. Gentamicin ototoxicity is vestibular, not cochlear, producing permanent loss of balance, but not of hearing. Gentamicin can be vestibulotoxic in any dose, in any regimen, at any serum level.

Effect of a Mindfulness Training Program on the Impulsivity and Aggression Levels of Adolescents with Behavioral Problems in the Classroom.

PubMed

Franco, Clemente; Amutio, Alberto; López-González, Luís; Oriol, Xavier; Martínez-Taboada, Cristina

2016-01-01

Objective: The aim of the present study was to analyze the effects of a mindfulness training psycho-educative program on impulsivity and aggression levels in a sample of high school students. Methods: A randomized controlled trial with pre-test-post-test measurements was applied to an experimental group and a control group (waiting list). The Barratt Impulsivity Scale (BIS-11) Patton et al. (1995) and the Aggression Questionnaire (Buss and Perry, 1992) were used. Results: Statistical analyses showed a significant decrease in the levels of impulsivity and aggressiveness in the experimental group compared with the control group. These results have important implications for improving the level of academic engagement and self-efficacy of students and for reducing school failure. Conclusion: This is one of the first studies showing the effectiveness of mindfulness training at reducing impulsive and aggressive behaviors in the classroom. The efficacy of mindfulness-based programs is emphasized.

Future orientation, impulsivity, and problem behaviors: a longitudinal moderation model.

PubMed

Chen, Pan; Vazsonyi, Alexander T

2011-11-01

In the current study, based on a sample of 1,873 adolescents between 11.4 and 20.9 years of age from the first 3 waves of the National Longitudinal Study of Adolescent Health, we investigated the longitudinal effects of future orientation on levels of and developmental changes in problem behaviors, while controlling for the effects by impulsivity; we also tested the moderating effects by future orientation on the impulsivity-problem behaviors link over time. Additionally, we examined future orientation operationalized by items measuring education, marriage, and life domains. Findings based on growth curve analyses provided evidence of longitudinal effects by education and life future orientation on both levels of and developmental changes in problem behaviors; the effect of marriage future orientation was not significant for either test. In addition, only life future orientation moderated the effect by impulsivity on levels of problem behaviors over time. More specifically, impulsivity had a weaker effect on levels of problem behaviors over time for adolescents who reported higher levels of life future orientation.

Reflective-impulsive style and conceptual tempo in a gross motor task.

PubMed

Keller, J; Ripoll, H

2001-06-01

The reflective-impulsive construct refers to responses made slowly or quickly in a situation with high uncertainty. Children who are labeled "reflective" take a longer time to respond and make few errors, whereas "impulsive" children are fast and inaccurate. Although the validity of the test and the definition of reflective-impulsive style are well accepted, whether such respond fast or slow to all tasks is questioned. Some children do not fit the dichotomy. Two other groups arise, the fast-accurate and the slow-inaccurate. The response styles of 86 boys, ages 5, 7, and 9 years performing a gross motor task, i.e., hitting a ball with a racquet, were studied. Analysis indicated that the slowest children on the Matching Familiar Figures Test can be faster than the fastest ones and remain more accurate. As the definition of the reflective-impulsive style is based on time, the reflective ones might better be viewed as children who can adapt the response time to the context and thus be more efficient at problem-solving.

Comparison among various methods of assessment of impulsiveness.

PubMed

Carrillo-de-la-Peña, M T; Otero, J M; Romero, E

1993-10-01

The current confused status of the research on impulsivity may be attributed to the lack of precise definitions, the reliance of most operationalizations on a single index, and inconsistency among different measures of the construct. Empirical measurements of impulsivity by self-reports, rating scales, or performance tasks suggest that the instruments employed measure aspects that have very little in common, a finding that throws serious doubts on the validity of the construct and implies a need for further research. To clarify this topic, we applied four different measures of impulsivity to 46 7th-grade (12 to 13 years old) schoolchildren. The children were rated by their teachers on an impulsivity behavior scale and were administered Kagan's Matching Familiar Figures Test, Version MFF-20, and two self-report forms, the Eysenck Impulsiveness Questionnaire, and the Barratt Impulsiveness Scale. Although the results confirmed the lack of convergence among these measures, high latencies on matching were associated with the cognitive aspect of the self-report scales. Treating impulsivity as a multidimensional construct is discussed.

Comparing Effectiveness of Mindfulness-Based Relapse Prevention with Treatment as Usual on Impulsivity and Relapse for Methadone-Treated Patients: A Randomized Clinical Trial.

PubMed

Yaghubi, Mehdi; Zargar, Fatemeh; Akbari, Hossein

2017-07-01

Impulsivity is one of the causes of relapse that can affect treatment outcomes. Studies have shown that addiction treatments can reduce impulsivity in drug-dependent individuals. Studies also have suggested that mindfulness is associated with impulsivity. However, no study has investigated the effectiveness of the mindfulness-based intervention on impulsivity in opioid-dependent individuals. This study aimed to compare the effectiveness of mindfulness-based relapse prevention (MBRP) with treatment as usual (TAU) in terms of impulsivity and relapse for methadone-treated patients. The present randomized controlled clinical trial was performed in Kashan, Iran, in 2015. The study population was opioid-dependent patients referred to Maintenance Treatment Centers. Seventy patients were selected by random sampling and were assigned in two groups (MBRP and TAU) randomly. The participants of two groups filled out Barratt impulsivity scale (BIS-11) as a pre-test and 8 weeks later as post-test and 2 months later as a follow-up. Both groups received methadone-therapy. The MBRP group received 8 sessions of group therapy, while the control group did not receive any group psychotherapy session. Finally, data from 60 patients were analyzed statistically. The MBRP group had decreased impulsivity significantly (P < 0.001). The mean impulsivity score was 74.76 ± 4.72 before intervention that was significantly decreased to 57.66 ± 3.73 and 58.86 ± 3.57 after the intervention and follow-up (P < 0.001), respectively. In addition, significant differences were observed between MBRP and TAU groups for relapse frequency (P < 0.050). This study showed that MBRP compared to TAU can decrease the mean impulsivity score in opioid-dependent and reduce relapse probability. These findings suggest that MBRP is useful for opioid-dependent individuals with high-level impulsivity, and relapse prevention.

Mission Analysis for Multiple Rendezvous of Near-Earth Asteroids Using Earth Gravity Assist

DTIC Science & Technology

2010-03-01

devices. Finding solutions with this approach leads to a quicker timeline for possible missions since one does not have to wait for the propulsion...in this research. The discussion focuses on their approach to the problem and the applicability to this research. The headings are the titles of... approach the problem utilizing conventional impulsive thrust propulsion systems and utilize data presented from the JPL website for locating the

Impulse noise generator--design and operation.

PubMed

Brinkmann, H

1991-01-01

In the seventies PFANDER (Pfander, 1975) proposed a screening test with an impulse noise simulator to check the particular responsivity of soldiers on vulnerability of the inner ear concerning the impulse noise-induced hearing loss. According to a system developed at the University of Oldenburg (Germany) (Klug & Radek, 1987), we have constructed an impulse noise generator designed for our specific requirements that will be presented. The simulator consists of an electrical ignited impulse noise spark gap which is supplied by a 3.5 kV high voltage source. At a distance of 1.10 m from the center of the impulse noise spark gap a peak pressure level of 155 dB with a C-Duration (Pfander, 1975) of .2 msec and with the main energy in the frequency range from 1 kHz to 2 kHz was good reproducible. It would be preferable to shift the impulse noise spectrum to lower frequencies but experimental effort has failed so far.

Development of a PPT for the EO-1 Spacecraft

NASA Technical Reports Server (NTRS)

Benson, Scott W.; Arrington, Lynn A.; Hoskins, W. Andrew; Meckel, Nicole J.

2000-01-01

A Pulsed Plasma Thruster (PPT) has been developed for use in a technology demonstration flight experiment on the Earth Observing 1 (EO-1) New Millennium Program mission. The thruster replaces the spacecraft pitch axis momentum wheel for control and momentum management during an experiment of a minimum three-day duration. The EO-1 PPT configuration is a combination of new technology and design heritage from similar systems flown in the 1970's and 1980's. Acceptance testing of the protoflight unit has validated readiness for flight, and integration with the spacecraft, including initial combined testing, has been completed. The thruster provides a range of capability from 90 microN-sec impulse bit at 650 sec specific impulse for 12 W input power, through 860 microN-sec impulse bit at 1400 see specific impulse for 70 W input power. Development of this thruster reinitiates technology research and development and re-establishes an industry base for production of flight hardware. This paper reviews the EO-1 PPT development, including technology selection, design and fabrication, acceptance testing, and initial spacecraft integration and test.

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Bill Prosser (left) and Eric Madaras, NASA-Langley Research Center, conduct impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

NASA Image and Video Library

2003-10-27

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Bill Prosser (left) and Eric Madaras, NASA-Langley Research Center, conduct impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

Acute necrosis after Gamma Knife surgery in vestibular schwannoma leading to multiple cranial nerve palsies.

PubMed

Kapitza, Sandra; Pangalu, Athina; Horstmann, Gerhard A; van Eck, Albert T; Regli, Luca; Tarnutzer, Alexander A

2016-08-01

We discuss a rare acute complication after Gamma Knife therapy (Elekta AB, Stockholm, Sweden) in a single patient. A 52-year-old woman presented with vertigo, facial weakness and hearing loss emerging 48hours following Gamma Knife radiosurgery for a right-sided vestibular schwannoma. Neurological examination 6days after symptom onset showed right-sided facial palsy, spontaneous left-beating nystagmus and pathologic head-impulse testing to the right. Pure-tone audiogram revealed right-sided sensorineural hearing loss. A diagnosis of acute vestibulocochlear and facial neuropathy was made. Brain MRI demonstrated focal contrast sparing within the schwannoma, likely related to acute radiation necrosis. Acute multiple cranial neuropathies of the cerebellopontine angle after Gamma Knife treatment should raise suspicion of acute tissue damage within the schwannoma and should result in urgent MRI. Treatment with steroids may be considered based on accompanying swelling and edema. Copyright © 2016 Elsevier Ltd. All rights reserved.

Depression, Impulse Control Disorder, and Life Style According to Smartphone Addiction.

PubMed

Kim, E Y; Joo, S W; Han, S J; Kim, M J; Choi, S Y

2017-01-01

We examined depression, impulse control disorder, and life style by degree of smartphone addiction. Chi-square tests and ANOVA were used to identify significant variables. CART was used to generate a decision making diagram of variables affecting smartphone addiction. The severe smartphone addiction group had rates of depression and impulse control disorder than the initial smartphone group.

Double-dissociation between the mechanism leading to impulsivity and inattention in Attention Deficit Hyperactivity Disorder: A resting-state functional connectivity study.

PubMed

Sanefuji, Masafumi; Craig, Michael; Parlatini, Valeria; Mehta, Mitul A; Murphy, Declan G; Catani, Marco; Cerliani, Leonardo; Thiebaut de Schotten, Michel

2017-01-01

Two core symptoms characterize Attention Deficit Hyperactivity Disorder (ADHD) subtypes: inattentiveness and hyperactivity-impulsivity. While previous brain imaging research investigated ADHD as if it was a homogenous condition, its two core symptoms may originate from different brain mechanisms. We, therefore, hypothesized that the functional connectivity of cortico-striatal and attentional networks would be different between ADHD subtypes. We studied 165 children (mean age 10.93 years; age range, 7-17 year old) diagnosed as having ADHD based on their revised Conner's rating scale score and 170 typical developing individuals (mean age 11.46 years; age range, 7-17 year old) using resting state functional fMRI. Groups were matched for age, IQ and head motion during the MRI acquisition. We fractionated the ADHD group into predominantly inattentive, hyperactive-impulsive and combined subtypes based on their revised Conner's rating scale score. We then analyzed differences in resting state functional connectivity of the cortico-striatal and attentional networks between these subtypes. We found a double dissociation of functional connectivity in the cortico-striatal and ventral attentional networks, reflecting the subtypes of the ADHD participants. Particularly, the hyperactive-impulsive subtype was associated with increased connectivity in cortico-striatal network, whereas the inattentive subtype was associated with increased connectivity in the right ventral attention network. Our study demonstrated for the first time a right lateralized, double dissociation between specific networks associated with hyperactivity-impulsivity and inattentiveness in ADHD children, providing a biological basis for exploring symptom dimensions and revealing potential targets for more personalized treatments. Copyright © 2016 Elsevier Ltd. All rights reserved.

[The relationship of attachment features and multi-impulsive symptoms in eating disorders].

PubMed

Szalai, Tamás Dömötör

2017-07-01

Attachment dysfunctions determine borderline personality disorder, which is a frequent background factor of multi-impulsivity; however, the relationship between attachment and multi-impulsive eating disorders is almost unexplored. To compare attachment features of multi-impulsive and classical eating disorder patients with individuals without eating disorders, and to test attachment as a predictor of multi-impulsivity. A cross-sectional survey (148 females, mean age: 30.9 years) investigated maternal, paternal and adult attachment, depression, anxiety, eating disorder and multi-impulsive symptoms in these groups. Altogether 41.3% of the individuals without eating disorders, 17.6% of classical and 11.8% of multi-impulsive eating disorder patients had secure attachment. Multi-impulsive patients had the most severe eating disorder symptoms (F (2) = 17.733) and the lowest paternal care (F (2) = 3.443). Preoccupied and fearful attachment explained 14.5% of multi-impulsive symptoms; however, with adjustment for depression only latter one remained the predictor of multi-impulsivity (t = 5.166, p<0.01). Multi-impulsives are a distinct subgroup of eating disorder patients from the aspects of both symptoms and attachment. Handling their negative moods may hold therapeutic potentials. Longitudinal studies are required to investigate the therapeutic value of paternal care, attachment preoccupation and fearfulness. Orv Hetil. 2017; 158(27): 1058-1066.

Influence of intertrial interval on basal and drug-induced impulsive action in the 5-choice serial reaction time task: Effects of d-amphetamine and (±)-2,5-dimethoxy-4-iodoamphetamine (DOI).

PubMed

Fitzpatrick, Ciaràn M; Maric, Vojislav S; Bate, Simon T; Andreasen, Jesper T

2018-01-01

Impulsivity is a characteristic of a number of neuropsychiatric disorders such as attention-deficit/hyperactivity disorder. The 5-choice serial reaction time task (5-CSRTT) is a rodent paradigm extensively used to assess attention and impulsivity. Notably, 5-CSRTT studies do not typically account for the reduction in premature responding, the measure of impulsive action, occurring upon repeated exposure to test sessions with long or variable intertrial intervals (ITIs). This present 5-CSRTT study investigated the use of variable ITIs (5, 10 or 15s) across 15 test days (4 training days followed by 1 drug test day per week for three weeks) as previous experience had shown that 4 training days would be sufficient to induce consistent premature response levels in male C57BL/6J mice. Once a steady state was achieved, the effects of dextroamphetamine (AMPH) and (±)-2,5-dimethoxy-4-iodoamphetamine (DOI) were then assessed using a Latin-square design to determine whether pharmacological-induced impulsive actions depended on ITI length. Mice habituated to the variable ITI schedule after only 3days and showed consistently lower premature response levels until the end of the study. AMPH (p<0.05) and DOI (p<0.05) increased the percentage of premature responses at 15s ITI trials, while only DOI (p<0.05) increased impulsive action at 10s ITI trials. Additionally, DOI increased omission rates (p<0.001), mean correct latency (p<0.01), reward collection latency (p<0.001), and reduced the total attempted trials (p<0.001). In summary, we demonstrated that mice habituate to the variable ITI schedule, suggesting that using the variable ITI schedule during training allowed premature response rates to stabilize before commencing pharmacological testing. Moreover, in these habituated mice AMPH and DOI significantly enhanced impulsive action at the long ITI trials only. We propose that experimental design considerations can improve the sensitivity of the 5-CSRTT to detect pharmacologicallyinduced impulsive action. Copyright © 2017 Elsevier B.V. All rights reserved.

Test stand for precise measurement of impulse and thrust vector of small attitude control jets

NASA Technical Reports Server (NTRS)

Woodruff, J. R.; Chisel, D. M.

1973-01-01

A test stand which accurately measures the impulse bit and thrust vector of reaction jet thrusters used in the attitude control system of space vehicles has been developed. It can be used to measure, in a vacuum or ambient environment, both impulse and thrust vector of reaction jet thrusters using hydrazine or inert gas propellants. The ballistic pendulum configuration was selected because of its accuracy, simplicity, and versatility. The pendulum is mounted on flexure pivots rotating about a vertical axis at the center of its mass. The test stand has the following measurement capabilities: impulse of 0.00004 to 4.4 N-sec (0.00001 to 1.0 lb-sec) with a pulse duration of 0.5 msec to 1 sec; static thrust of 0.22 to 22 N (0.05 to 5 lb) with a 5 percent resolution; and thrust angle alinement of 0.22 to 22 N (0.05 to 5 lb) thrusters with 0.01 deg accuracy.

A path model of different forms of impulsivity with externalizing and internalizing psychopathology: Towards greater specificity.

PubMed

Johnson, Sheri L; Tharp, Jordan A; Peckham, Andrew D; Carver, Charles S; Haase, Claudia M

2017-09-01

A growing empirical literature indicates that emotion-related impulsivity (compared to impulsivity that is unrelated to emotion) is particularly relevant for understanding a broad range of psychopathologies. Recent work, however, has differentiated two forms of emotion-related impulsivity: A factor termed Pervasive Influence of Feelings captures tendencies for emotions (mostly negative emotions) to quickly shape thoughts, and a factor termed Feelings Trigger Action captures tendencies for positive and negative emotions to quickly and reflexively shape behaviour and speech. This study used path modelling to consider links from emotion-related and non-emotion-related impulsivity to a broad range of psychopathologies. Undergraduates completed self-report measures of impulsivity, depression, anxiety, aggression, and substance use symptoms. A path model (N = 261) indicated specificity of these forms of impulsivity. Pervasive Influence of Feelings was related to anxiety and depression, whereas Feelings Trigger Action and non-emotion-related impulsivity were related to aggression and substance use. The findings of this study suggest that emotion-relevant impulsivity could be a potentially important treatment target for a set of psychopathologies. Recent work has differentiated two forms of emotion-related impulsivity. This study tests a multivariate path model linking emotion-related and non-emotion-related impulsivity with multiple forms of psychopathology. Impulsive thoughts in response to negative emotions were related to anxiety and depression. Impulsive actions in response to emotions were related to aggression and substance use, as did non-emotion-related impulsivity. The study was limited by the reliance on self-report measures of impulsivity and psychopathology. There is a need for longitudinal work on how these forms of impulsivity predict the onset and course of psychopathology. © 2017 The British Psychological Society.

Robust Lee local statistic filter for removal of mixed multiplicative and impulse noise

NASA Astrophysics Data System (ADS)

Ponomarenko, Nikolay N.; Lukin, Vladimir V.; Egiazarian, Karen O.; Astola, Jaakko T.

2004-05-01

A robust version of Lee local statistic filter able to effectively suppress the mixed multiplicative and impulse noise in images is proposed. The performance of the proposed modification is studied for a set of test images, several values of multiplicative noise variance, Gaussian and Rayleigh probability density functions of speckle, and different characteris-tics of impulse noise. The advantages of the designed filter in comparison to the conventional Lee local statistic filter and some other filters able to cope with mixed multiplicative+impulse noise are demonstrated.

Selective and interactive effects of D2 receptor antagonism and positive allosteric mGluR4 modulation on waiting impulsivity.

PubMed

Isherwood, Sarah N; Robbins, Trevor W; Nicholson, Janet R; Dalley, Jeffrey W; Pekcec, Anton

2017-09-01

Metabotropic glutamate receptor 4 (mGluR4) and dopamine D 2 receptors are specifically expressed within the indirect pathway neurons of the striato-pallidal-subthalamic pathway. This unique expression profile suggests that mGluR4 and D 2 receptors may play a cooperative role in the regulation and inhibitory control of behaviour. We investigated this possibility by testing the effects of a functionally-characterised positive allosteric mGluR4 modulator, 4-((E)-styryl)-pyrimidin-2-ylamine (Cpd11), both alone and in combination with the D 2 receptor antagonist eticlopride, on two distinct forms of impulsivity. Rats were trained on the five-choice serial reaction time task (5-CSRTT) of sustained visual attention and segregated according to low, mid, and high levels of motor impulsivity (LI, MI and HI, respectively), with unscreened rats used as an additional control group. A separate group of rats was trained on a delay discounting task (DDT) to assess choice impulsivity. Systemic administration of Cpd11 dose-dependently increased motor impulsivity and impaired attentional accuracy on the 5-CSRTT in all groups tested. Eticlopride selectively attenuated the increase in impulsivity induced by Cpd11, but not the accompanying attentional impairment, at doses that had no significant effect on behavioural performance when administered alone. Cpd11 also decreased choice impulsivity on the DDT (i.e. increased preference for the large, delayed reward) and decreased locomotor activity. These findings demonstrate that mGluR4s, in conjunction with D 2 receptors, affect motor- and choice-based measures of impulsivity, and therefore may be novel targets to modulate impulsive behaviour associated with a number of neuropsychiatric syndromes. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Associations among types of impulsivity, substance use problems and neurexin-3 polymorphisms.

PubMed

Stoltenberg, Scott F; Lehmann, Melissa K; Christ, Christa C; Hersrud, Samantha L; Davies, Gareth E

2011-12-15

Some of the genetic vulnerability for addiction may be mediated by impulsivity. This study investigated relationships among impulsivity, substance use problems and six neurexin-3 (NRXN3) polymorphisms. Neurexins (NRXNs) are presynaptic transmembrane proteins that play a role in the development and function of synapses. Impulsivity was assessed with the Barratt Impulsiveness Scale Version 11 (BIS-11), the Boredom Proneness Scale (BPS) and the TIME paradigm; alcohol problems with the Michigan Alcoholism Screening Test (MAST); drug problems with the Drug Abuse Screening Test (DAST-20); and regular tobacco use with a single question. Participants (n=439 Caucasians, 64.7% female) donated buccal cells for genotyping. Six NRXN3 polymorphisms were genotyped: rs983795, rs11624704, rs917906, rs1004212, rs10146997 and rs8019381. A dual luciferase assay was conducted to determine whether allelic variation at rs917906 regulated gene expression. In general, impulsivity was significantly higher in those who regularly used tobacco and/or had alcohol or drug problems. In men, there were modest associations between rs11624704 and attentional impulsivity (p=0.005) and between rs1004212 and alcohol problems (p=0.009). In women, there were weak associations between rs10146997 and TIME estimation (p=0.03); and between rs1004212 and drug problems (p=0.03). The dual luciferase assay indicated that C and T alleles of rs917906 did not differentially regulate gene expression in vitro. Associations between impulsivity, substance use problems and polymorphisms in NRXN3 may be gender specific. Impulsivity is associated with substance use problems and may provide a useful intermediate phenotype for addiction. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Impulsivity and Stress Response in Pathological Gamblers During the Trier Social Stress Test.

PubMed

Maniaci, G; Goudriaan, A E; Cannizzaro, C; van Holst, R J

2018-03-01

Gambling has been associated with increased sympathetic nervous system output and stimulation of the hypothalamic-pituitary-adrenal axis. However it is unclear how these systems are affected in pathological gambling. This study aimed to investigate the effect of the Trier Social Stress Test (TSST) on cortisol and on cardiac interbeat intervals in relation to impulsivity, in a sample of male pathological gamblers compared to healthy controls. In addition, we investigated the correlation between the TSST, duration of the disorder and impulsivity. A total of 35 pathological gamblers and 30 healthy controls, ranging from 19 to 58 years old and all male, participated in this study. Stress response was measured during and after the TSST by salivary cortisol and cardiac interbeat intervals; impulsivity was assessed with the Barratt Impulsiveness Scale (BIS-11). Exposure to the TSST produced a significant increase in salivary cortisol and interbeat intervals in both groups, without differences between groups. We found a negative correlation between baseline cortisol and duration of pathological gambling indicating that the longer the duration of the disorder the lower the baseline cortisol levels. Additionally, we found a main effect of impulsivity across groups on interbeat interval during the TSST, indicating an association between impulsivity and the intensity of the neurovegetative stress response during the TSST. Involvement of the hypothalamic-pituitary-adrenal axis in pathological gambling was confirmed together with evidence of a correlation between length of the disorder and diminished baseline cortisol levels. Impulsivity emerged as a personality trait expressed by pathological gamblers; however the neurovegetative response to the TSST, although associated with impulsivity, appeared to be independent of the presence of pathological gambling.

Enhanced attention and impulsive action following NMDA receptor GluN2B-selective antagonist pretreatment.

PubMed

Higgins, Guy A; Silenieks, Leo B; MacMillan, Cam; Sevo, Julia; Zeeb, Fiona D; Thevarkunnel, Sandy

2016-09-15

NMDA GluN2B (NR2B) subtype selective antagonists are currently in clinical development for a variety of indications, including major depression. We previously reported the selective NMDA GluN2B antagonists Ro 63-1908 and traxoprodil, increase premature responding in a 5-choice serial reaction time task (5-CSRTT) suggesting an effect on impulsive action. The present studies extend these investigations to a Go-NoGo and delay discounting task, and the 5-CSRTT under test conditions of both regular (5s) and short (2-5s) multiple ITI (Intertrial interval). Dizocilpine was included for comparison. Both Ro 63-1908 (0.1-1mg/kg SC) and traxoprodil (0.3-3mg/kg SC) increased premature and perseverative responses in both 5-CSRT tasks and improved attention when tested under a short ITI test condition. Ro 63-1908 but not traxoprodil increased motor impulsivity (false alarms) in a Go-NoGo task. Dizocilpine (0.01-0.06mg/kg SC) affected both measures of motor impulsivity and marginally improved attention. In a delay discounting test of impulsive choice, both dizocilpine and Ro 63-1908 decreased impulsive choice (increased choice for the larger, delayed reward), while traxoprodil showed a similar trend. Motor stimulant effects were evident following Ro 63-1908, but not traxoprodil treatment - although no signs of motor stereotypy characteristic of dizocilpine (>0.1mg/kg) were noted. The findings of both NMDA GluN2B antagonists affecting measures of impulsive action and compulsive behavior may underpin emerging evidence to suggest glutamate signaling through the NMDA GluN2B receptor plays an important role in behavioural flexibility. The profiles between Ro 63-1908 and traxoprodil were not identical, perhaps suggesting differences between members of this drug class. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of the utility of Liebowitz Social Anxiety Scale and Barratt Impulsiveness Scale in the diagnosis of social anxiety, impulsivity and depression.

PubMed

Tyrała, Kinga; Seweryn, Mariusz; Bonk, Magdalena; Bulska, Weronika; Orszulak, Kamila; Bratek, Agnieszka; Krysta, Krzysztof

2015-09-01

Often mental disorders are serious problems concerning psychological well-being. They require comprehensive and specialized psychiatric and psychological help, but there are no public methods of controlling your mental state. The aim of study was the evaluation of the utility of Liebowitz Social Anxiety Scale and Barratt Impulsiveness Scale in the diagnosis of social anxiety, impulsivity and depression. The study included 85 persons. The study group had 34 patients treated in an open ward of the Department of Psychiatry and Psychotherapy of Medical University of Silesia in Katowice. The control group included 51 persons without mental disorders. Three self-rating questionnaires were used: Beck Depression Inventory, Barratt Impulsiveness Scale and Liebowitz Social Anxiety Scale. Statistica v10 Statsoft software was used for statistical analysis. The analyzed groups had significant differences in terms of Beck Scale (U Mann-Whitney test p=0.000001). Average score in study group: 22.94±12.50; in control group: 7.15±6.44. Groups had significant differences in terms of Liebowitz Scale (U test Mann-Whitney test, p=0.000164). Average score in the study group: 60.41±30.30; in control group: 35.01±23.94. Groups had significant differences in terms of Barratt Scale (t-student test p=0.000601). Average in study group: 66.35±9,49; in control group: 59.54±7.87. Significant positive correlation was observed between the results of Beck Scale and Liebowitz Scale (r=0.64465). Correlation was not observed between the results of the Liebowitz and Barrat (r=0.12091 and Beck and Barrat (r=0.21482). The intensity of the Liebowitz Social Anxiety Scale is directly proportional to the severity of depression according to the Beck Depression Inventory. The degree of impulsivity by Barrat Impulsiveness Scale does not correlate with the level of depression according to Beck Depression Inventory. The analyzed scales are relevant in the diagnosis of mental disorders.

Interactive effects of cumulative stress and impulsivity on alcohol consumption.

PubMed

Fox, Helen C; Bergquist, Keri L; Peihua, Gu; Rajita, Sinha

2010-08-01

Alcohol addiction may reflect adaptations to stress, reward, and regulatory brain systems. While extensive research has identified both stress and impulsivity as independent risk factors for drinking, few studies have assessed the interactive relationship between stress and impulsivity in terms of hazardous drinking within a community sample of regular drinkers. One hundred and thirty regular drinkers (56M/74F) from the local community were assessed for hazardous and harmful patterns of alcohol consumption using the Alcohol Use Disorders Identification Test (AUDIT). All participants were also administered the Barratt Impulsiveness Scale (BIS-11) as a measure of trait impulsivity and the Cumulative Stress/Adversity Checklist (CSC) as a comprehensive measure of cumulative adverse life events. Standard multiple regression models were used to ascertain the independent and interactive nature of both overall stress and impulsivity as well as specific types of stress and impulsivity on hazardous and harmful drinking. Recent life stress, cumulative traumatic stress, overall impulsivity, and nonplanning-related impulsivity as well as cognitive and motor-related impulsivity were all independently predictive of AUDIT scores. However, the interaction between cumulative stress and total impulsivity scores accounted for a significant amount of the variance, indicating that a high to moderate number of adverse events and a high trait impulsivity rating interacted to affect greater AUDIT scores. The subscale of cumulative life trauma accounted for the most variance in AUDIT scores among the stress and impulsivity subscales. Findings highlight the interactive relationship between stress and impulsivity with regard to hazardous drinking. The specific importance of cumulative traumatic stress as a marker for problem drinking is also discussed.

A Study in West German Stabilization Policy, 1956-1974. German Studies Notes. First Draft.

ERIC Educational Resources Information Center

Neumann, Manfred J. M.

The dominant driving force of past movements in West German output and prices is investigated and a review of government policy undertaken to stabilize these movements is presented. Three alternative impulse hypotheses are tested: the monetary, the fiscal, and the foreign impulse hypothesis. The major results of the tests are that: (1) monetary…

Twin Study on Heritability of Activity, Attention, and Impulsivity as Assessed by Objective Measures

ERIC Educational Resources Information Center

Heiser, Philip; Heinzel-Gutenbrunner, Monika; Frey, Joachim; Smidt, Judith; Grabarkiewicz, Justyna; Friedel, Susann; Kuhnau, Wolfgang; Schmidtke, Jorg; Remschmidt, Helmut; Hebebrand, Johannes

2006-01-01

Objective: The purpose of this study was to assess heritability of activity, attention, and impulsivity by comparing young monozygotic (MZ) twins with dizygotic (DZ) twins using objective measures. Method: The OPTAx test is an infrared motion analysis to record the movement pattern during a continuous performance test. Seventeen MZ and 12 same…

Interactive optimization approach for optimal impulsive rendezvous using primer vector and evolutionary algorithms

NASA Astrophysics Data System (ADS)

Luo, Ya-Zhong; Zhang, Jin; Li, Hai-yang; Tang, Guo-Jin

2010-08-01

In this paper, a new optimization approach combining primer vector theory and evolutionary algorithms for fuel-optimal non-linear impulsive rendezvous is proposed. The optimization approach is designed to seek the optimal number of impulses as well as the optimal impulse vectors. In this optimization approach, adding a midcourse impulse is determined by an interactive method, i.e. observing the primer-magnitude time history. An improved version of simulated annealing is employed to optimize the rendezvous trajectory with the fixed-number of impulses. This interactive approach is evaluated by three test cases: coplanar circle-to-circle rendezvous, same-circle rendezvous and non-coplanar rendezvous. The results show that the interactive approach is effective and efficient in fuel-optimal non-linear rendezvous design. It can guarantee solutions, which satisfy the Lawden's necessary optimality conditions.

[Association of loneliness, impulsivity and alcohol use with suicidal behavior in adolescents].

PubMed

Salvo G, Lilian; Castro S, Andrea

2013-04-01

Suicide and suicide attempts are public health problems. Their prevention requives the detection of predictor factors. To determine the predictive valué of loneliness, impulsivity and alcohol use on suicidal behavior in adolescents. Suicidal behavior, Loneliness (UCLA), Impulsivity (Barratt) scales and the Alcohol Use Disorders Identification Test (AUDIT), were applied to 763 high school students aged 14 to 19 years (49% males), living in Chillan, Chile. Nineteen percent of participants had attempted suicide and 34.3% had suicidal ideation. Loneliness, impulsivity and alcohol use were directly related to suicidal behavior. These predictors explained 31 % of the suicidal behavior. The most important risk factor was loneliness, followed by femóle gender, impulsivity and alcohol use. Loneliness, impulsivity and alcohol use are risk factors for suicide among adolescents. Women are at higher risk than men.

The Minimum Impulse Thruster

NASA Technical Reports Server (NTRS)

Parker, J. Morgan; Wilson, Michael J.

2005-01-01

The Minimum Impulse Thruster (MIT) was developed to improve the state-of-the-art minimum impulse capability of hydrazine monopropellant thrusters. Specifically, a new fast response solenoid valve was developed, capable of responding to a much shorter electrical pulse width, thereby reducing the propellant flow time and the minimum impulse bit. The new valve was combined with the Aerojet MR-103, 0.2 lbf (0.9 N) thruster and put through an extensive Delta-qualification test program, resulting in a factor of 5 reduction in the minimum impulse bit, from roughly 1.1 milli-lbf-seconds (5 milliNewton seconds) to - 0.22 milli-lbf-seconds (1 mN-s). To maintain it's extensive heritage, the thruster itself was left unchanged. The Minimum Impulse Thruster provides mission and spacecraft designers new design options for precision pointing and precision translation of spacecraft.

[Detection of hydrodynamically operative tissue in the substantia spongiosa of the femoral head in Bos taurus and Ovis aries].

PubMed

Copf, F; Czarnetzki, A; Lierse, W; Dolenc, A

1990-12-01

The authors show the presence of CC-Tensulae in Bos taurus and Ovis aries. They define CC-Tensulae as tense membranes in openings between the trabeculae of spongy bone. These structures were interpreted in man as a hydrodynamic subsystem which serves the flow and the impulses of mechanical forces. The authors point especially to the similarity that exists between their findings and what has been seen in man.

[A neuronal analysis of the hunting behavior of sea butterfly Clione limacina].

PubMed

Norekian, T P; Satterly, R

1991-01-01

Neurones of the cerebral ganglia controlling the movements of the hunting apparatus of predatory pelagic mollusc Clione limacina are described in detail. A large group is identified of high-threshold electrically interconnected neurones A, the impulse activity of which leads to the opening of the skin folds and throwing forward Clione catching tentacles. Neurones of B group, having constant background activity and receiving powerful inhibitory inputs from A cells, on the contrary, elicit contraction and drawing in of the hunting tentacles inside the head. The third group--C neurons, the impulse activity of which leads to tightening of the skin folds covering the hunting apparatus. The action has been studied on identified neurones of such transmitters as serotonine, dopamine and gamma-aminobutyric acid. Serotonine depolarises both A and B neurones, but activation of the hunting apparatus is an integrating effect: activated neurones A owing to powerful TPSP inhibit neurones B, interrupting direct exciting action of serotonine. Dopamine in different concentrations has an opposite effect: at low concentrations only B cells are activated and tentacles are drawn inside the head; at high ones the neurones A start working which inhibit B cells and activate the hunting apparatus. GABA renders to neurones, regulating the movements of the hunting apparatus a total, well coordinated action directed to activation of the hunting behaviour: it depolarises-activates A neurones and hyperpolarises-inhibits neurones of B and C groups.

Differences in Trait Impulsivity Indicate Diversification of Dog Breeds into Working and Show Lines.

PubMed

Fadel, Fernanda Ruiz; Driscoll, Patricia; Pilot, Malgorzata; Wright, Hannah; Zulch, Helen; Mills, Daniel

2016-03-10

Impulsiveness describes the inability to inhibit behaviour in the presence of salient cues. Trait-level impulsivity exists on a continuum and individual differences can be adaptive in different contexts. While breed related differences in behavioural tendency in the domestic dog (Canis familiaris) are well established, the phenomenon within lines of a breed which have been selected more recently is not well studied, although it may challenge the popular notion of breed-typical behaviour. We describe differences in impulsivity between and within two dog breeds with working and show lines selected for different levels of impulsivity: Border Collies (herding work) and Labrador Retrievers (gun work). Recent show line selection might have lessened differences in impulsivity between breeds. We tested this hypothesis on a dataset of 1161 individuals assessed using a validated psychometric tool (Dog Impulsivity Assessment Scale--DIAS). Collies were more impulsive on average, consistent with the original purpose of breed selection. Regarding line, working Collies differed from working Labradors, but show lines from the two breeds were not significantly different. Altered or relaxed artificial selection for behavioural traits when appearance rather than behaviour become the primary focus for breeders may reduce average differences in impulsivity between breeds in show lines.

I can't wait: Methods for measuring and moderating individual differences in impulsive choice.

PubMed

Peterson, Jennifer R; Hill, Catherine C; Marshall, Andrew T; Stuebing, Sarah L; Kirkpatrick, Kimberly

2015-01-01

Impulsive choice behavior occurs when individuals make choices without regard for future consequences. This behavior is often maladaptive and is a common symptom in many disorders, including drug abuse, compulsive gambling, and obesity. Several proposed mechanisms may influence impulsive choice behavior. These mechanisms provide a variety of pathways that may provide the basis for individual differences that are often evident when measuring choice behavior. This review provides an overview of these different pathways to impulsive choice, and the behavioral intervention strategies being developed to moderate impulsive choice. Because of the compelling link between impulsive choice behavior and the near-epidemic pervasiveness of obesity in the United States, we focus on the relationship between impulsive choice behavior and obesity as a test case for application of the multiple pathways approach. Choosing immediate gratification over healthier long term food choices is a contributing factor to the obesity crisis. Behavioral interventions can lead to more self controlled choices in a rat pre-clinical model, suggesting a possible gateway for translation to human populations. Designing and implementing effective impulsive choice interventions is crucial to improving the overall health and well-being of impulsive individuals.

Impulsivity in abstinent early- and late-onset alcoholics: differences in self-report measures and a discounting task.

PubMed

Dom, G; D'haene, P; Hulstijn, W; Sabbe, B

2006-01-01

To test the hypothesis that early-onset alcoholics (EOAs) can be differentiated from late-onset alcoholics (LOAs) by more severe substance-related problems and higher levels of impulsivity and aggression. A cross-sectional patient survey with a community comparison group. The European Addiction Severity Index was used to assess substance-related problems and the Barratt Impulsiveness Scale, the Dutch version of the Zuckermann Sensation Seeking Scale and the Buss-Durkee Hostility Inventory were used to assess impulsive and aggressive traits. Impulsive decision making was assessed using a delay discounting task (DDT) with hypothetical monetary rewards. Participants were EOAs (n = 42) and LOAs (n = 46) recruited from an addiction treatment centre and an unmatched, non-substance-abusing comparison group (n = 54). Findings The EOAs had higher levels of impulsive decision making than both the LOAs and the comparison group. The EOAs had higher scores than the LOAs on measures of impulsiveness, aggressiveness and the severity of substance-related problems. This study provides evidence that EOAs are more impulsive and aggressive than LOAs. Further identification of alcoholism subtypes based on dimensions of impulsivity should be considered in the light of their relationship with pharmacological and behavioural treatment interventions.

Gender differences in the relationship between impulsivity and disordered eating behaviors and attitudes.

PubMed

Lundahl, Alyssa; Wahlstrom, Laura C; Christ, Christa C; Stoltenberg, Scott F

2015-08-01

We investigated relationships among gender, impulsivity and disordered eating in healthy college students. Participants (N=1223) were healthy, undergraduate men (28.5%) and women (71.5%), who completed the Barratt Impulsiveness Scale - Version 11 (BIS-11) and a four-factor version of the Eating Attitudes Test (EAT-16). As predicted, mean scores on all four EAT-16 factors were significantly higher for women than for men. Attentional impulsivity was related to poorer self-perception of body shape, more dieting, and a greater preoccupation with food for the sample as a whole. Moreover, motor impulsivity was related to poorer self-perceptions of body shape and a greater preoccupation with food. However, no gender differences emerged in the relationship between impulsivity and disordered eating attitudes. This study elucidates the role of impulsivity in disordered eating behaviors among non-clinical college students. For both women and men, attentional and motor impulsivity were related to disordered eating attitudes and behaviors. Overall, these findings suggest that different facets of impulsivity are related to disordered eating attitudes and behaviors in a non-clinical college population. Copyright © 2015 Elsevier Ltd. All rights reserved.

I can't wait: Methods for measuring and moderating individual differences in impulsive choice

PubMed Central

Peterson, Jennifer R.; Hill, Catherine C.; Marshall, Andrew T.; Stuebing, Sarah L.; Kirkpatrick, Kimberly

2016-01-01

Impulsive choice behavior occurs when individuals make choices without regard for future consequences. This behavior is often maladaptive and is a common symptom in many disorders, including drug abuse, compulsive gambling, and obesity. Several proposed mechanisms may influence impulsive choice behavior. These mechanisms provide a variety of pathways that may provide the basis for individual differences that are often evident when measuring choice behavior. This review provides an overview of these different pathways to impulsive choice, and the behavioral intervention strategies being developed to moderate impulsive choice. Because of the compelling link between impulsive choice behavior and the near-epidemic pervasiveness of obesity in the United States, we focus on the relationship between impulsive choice behavior and obesity as a test case for application of the multiple pathways approach. Choosing immediate gratification over healthier long term food choices is a contributing factor to the obesity crisis. Behavioral interventions can lead to more self controlled choices in a rat pre-clinical model, suggesting a possible gateway for translation to human populations. Designing and implementing effective impulsive choice interventions is crucial to improving the overall health and well-being of impulsive individuals. PMID:27695664

Twin study on heritability of activity, attention, and impulsivity as assessed by objective measures.

PubMed

Heiser, Philip; Heinzel-Gutenbrunner, Monika; Frey, Joachim; Smidt, Judith; Grabarkiewicz, Justyna; Friedel, Susann; Kühnau, Wolfgang; Schmidtke, Jörg; Remschmidt, Helmut; Hebebrand, Johannes

2006-05-01

The purpose of this study was to assess heritability of activity, attention, and impulsivity by comparing young monozygotic (MZ) twins with dizygotic (DZ) twins using objective measures. The OPTAx test is an infrared motion analysis to record the movement pattern during a continuous performance test. Seventeen MZ and 12 same sexed DZ twin pairs in the range of 6 to 12 years were tested. The zygosity was determined by DNA-fingerprinting. The measures under investigation were activity (microevents and spatial scaling), impulsivity (errors of commission), and attention (accuracy and variability). For statistical analyses, the classical model of Falconer and the ACE and ADE genetic model for twin data were applied in order to estimate the proportion of the variance in activity, impulsivity and attention that is due to genetic effects. The respective coefficients of intraclass correlations in MZ twins ranged between .35 and .65 whereas for DZ twins the correlations were between .12 and .88. The heritability estimates resulting from both models were about 30% for 4 of the 5 measures, but none of these was significantly different from 0. We found no significant influence of genetic factors for activity, attention, and impulsivity. The authors conclude that further investigation of heritability of ADHD is necessary using larger sample sizes and objective measures.

The error-related negativity (ERN) is an electrophysiological marker of motor impulsiveness on the Barratt Impulsiveness Scale (BIS-11) during adolescence.

PubMed

Taylor, Jasmine B; Visser, Troy A W; Fueggle, Simone N; Bellgrove, Mark A; Fox, Allison M

2018-04-01

Previous studies have postulated that the error-related negativity (ERN) may reflect individual differences in impulsivity; however, none have used a longitudinal framework or evaluated impulsivity as a multidimensional construct. The current study evaluated whether ERN amplitude, measured in childhood and adolescence, is predictive of impulsiveness during adolescence. Seventy-five children participated in this study, initially at ages 7-9 years and again at 12-18 years. The interval between testing sessions ranged from 5 to 9 years. The ERN was extracted in response to behavioural errors produced during a modified visual flanker task at both time points (i.e. childhood and adolescence). Participants also completed the Barratt Impulsiveness Scale - a measure that considers impulsiveness to comprise three core sub-traits - during adolescence. At adolescence, the ERN amplitude was significantly larger than during childhood. Additionally, ERN amplitude during adolescence significantly predicted motor impulsiveness at that time point, after controlling for age, gender, and the number of trials included in the ERN. In contrast, ERN amplitude during childhood did not uniquely predict impulsiveness during adolescence. These findings provide preliminary evidence that ERN amplitude is an electrophysiological marker of self-reported motor impulsiveness (i.e. acting without thinking) during adolescence. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Mechanisms of Individual Differences in Impulsive and Risky Choice in Rats

PubMed Central

Kirkpatrick, Kimberly; Marshall, Andrew T.; Smith, Aaron P.

2016-01-01

Individual differences in impulsive and risky choice are key risk factors for a variety of maladaptive behaviors such as drug abuse, gambling, and obesity. In our rat model, ordered individual differences are stable across choice parameters, months of testing, and span a broad spectrum, suggesting that rats, like humans, exhibit trait-level impulsive and risky choice behaviors. In addition, impulsive and risky choices are highly correlated, suggesting a degree of correlation between these two traits. An examination of the underlying cognitive mechanisms has suggested an important role for timing processes in impulsive choice. In addition, in an examination of genetic factors in impulsive choice, the Lewis rat strain emerged as a possible animal model for studying disordered impulsive choice, with this strain demonstrating deficient delay processing. Early rearing environment also affected impulsive behaviors, with rearing in an enriched environment promoting adaptable and more self-controlled choices. The combined results with impulsive choice suggest an important role for timing and reward sensitivity in moderating impulsive behaviors. Relative reward valuation also affects risky choice, with manipulation of objective reward value (relative to an alternative reference point) resulting in loss chasing behaviors that predicted overall risky choice behaviors. The combined results are discussed in relation to domain-specific versus domain-general subjective reward valuation processes and the potential neural substrates of impulsive and risky choice. PMID:27695580

Emotionally laden impulsivity interacts with affect in predicting addictive use of online sexual activity in men.

PubMed

Wéry, Aline; Deleuze, Jory; Canale, Natale; Billieux, Joël

2018-01-01

The interest in studying addictive use of online sexual activities (OSA) has grown sharply over the last decade. Despite the burgeoning number of studies conceptualizing the excessive use of OSA as an addictive disorder, few have tested its relations to impulsivity, which is known to constitute a hallmark of addictive behaviors. To address this missing gap in the literature, we tested the relationships between addictive OSA use, impulsivity traits, and affect among a convenience sample of men (N=182; age, M=29.17, SD = 9.34), building upon a theoretically driven model that distinguishes the various facets of impulsivity. Results showed that negative urgency (an impulsivity trait reflecting the tendency to act rashly in negative emotional states) and negative affect interact in predicting addictive OSA use. These results highlight the pivotal role played by negative urgency and negative affect in addictive OSA use, supporting the relevance of psychological interventions that focus on improving emotional regulation (e.g., to reduce negative affect and learn healthier coping strategies) to mitigate excessive use of OSA. Copyright © 2017 Elsevier Inc. All rights reserved.

Misdiagnosis of acute peripheral vestibulopathy in central nervous ischemic infarction.

PubMed

Braun, Eva Maria; Tomazic, Peter Valentin; Ropposch, Thorsten; Nemetz, Ulrike; Lackner, Andreas; Walch, Christian

2011-12-01

Vertigo is a very common symptom at otorhinolaryngology (ENT), neurological, and emergency units, but often, it is difficult to distinguish between vertigo of peripheral and central origin. We conducted a retrospective analysis of a hospital database, including all patients admitted to the ENT University Hospital Graz after neurological examination, with a diagnosis of peripheral vestibular vertigo and subsequent diagnosis of central nervous infarction as the actual cause for the vertigo. Twelve patients were included in this study. All patients with acute spinning vertigo after a thorough neurological examination and with uneventful computed tomographic scans were referred to our ENT department. Nine of them presented with horizontal nystagmus. Only 1 woman experienced additional hearing loss. The mean diagnostic delay to the definite diagnosis of a central infarction through magnetic resonance imaging was 4 days (SD, 2.3 d). A careful otologic and neurological examination, including the head impulse test and caloric testing, is mandatory. Because ischemic events cannot be diagnosed in computed tomographic scans at an early stage, we strongly recommend to perform cranial magnetic resonance imaging within 48 hours from admission if vertigo has not improved under conservative treatment.

Does Game Participation Impact Cognition and Symptoms in Elite Football Players?

PubMed

Mrazik, Martin; Naidu, Dhiren; Manning, David E; Brooks, Brian L

2016-09-01

To measure neurocognitive functioning in college and professional football players after game participation. Retrospective, cross-sectional cohort design. Ninety-four male university and professional football players. All participants completed Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) testing at baseline, and either at postconcussion (group 1) or postgame (group 2) participation. Results from the 5 ImPACT composite scores (Verbal Memory, Visual Memory, Visual Motor Speed, Reaction Time and Impulse Control) and Total Symptom Score. Repeated-measures analysis of variance demonstrated a significant main effect for time (improvements) in 3 of 5 domains for the postconcussion group, but no improvements in the postgame group. The postconcussion group presented with significantly improved results on 4 of 5 ImPACT domains compared with the postgame group at the follow-up time interval. Participation in a football game with potential cumulative head contacts did not yield increased symptoms or cognitive impairment. However, the absence of improvement in cognitive functioning in noninjured football players, which was found in those players who were returned to play after an injury, may suggest that there is a measureable impact as a result of playing football.

Sequence of the Essex-Lopresti lesion—a high-speed video documentation and kinematic analysis

PubMed Central

2014-01-01

Background and purpose The pathomechanics of the Essex-Lopresti lesion are not fully understood. We used human cadavers and documented the genesis of the injury with high-speed cameras. Methods 4 formalin-fixed cadaveric specimens of human upper extremities were tested in a prototype, custom-made, drop-weight test bench. An axial high-energy impulse was applied and the development of the lesion was documented with 3 high-speed cameras. Results The high-speed images showed a transversal movement of the radius and ulna, which moved away from each other in the transversal plane during the impact. This resulted into a transversal rupture of the interosseous membrane, starting in its central portion, and only then did the radius migrate proximally and fracture. The lesion proceeded to the dislocation of the distal radio-ulnar joint and then to a full-blown Essex-Lopresti lesion. Interpretation Our findings indicate that fracture of the radial head may be preceded by at least partial lesions of the interosseous membrane in the course of high-energy axial trauma. PMID:24479620

Are self-injurers impulsive?:Results from two behavioral laboratory studies

PubMed Central

Janis, Irene Belle; Nock, Matthew K.

2009-01-01

Common clinical wisdom suggests that people who engage in self-injury are impulsive. However, virtually all prior work in this area has relied on individuals’ self-report of impulsiveness, despite evidence that people are limited in their ability to accurately report on cognitive processes that occur outside awareness. To address this knowledge gap, we used performance-based measures of several dimensions of impulsiveness to assess whether people engaging in non-suicidal self-injury (NSSI) demonstrate greater impulsiveness than non-injurers. In Study 1, we compared adolescent self-injurers (n=64) to age, sex, and race/ethnicity matched, non-injurious controls (n=30) on self-report impulsiveness (Schedule for Affective Disorders and Schizophrenia for School Age Children, Present and Lifetime Version, Kaufman et al., 1997), and on performance-based measures of two dimensions of impulsiveness: behavioral disinhibition (Conners’ Continuous Performance Test, Connors, 1995) and risky decision-making (Iowa Gambling Task, Bechara et al., 1994). In Study 2, we compared adult female self-injurers (n=20) to age and race/ethnicity matched, non-injurious controls (n=20) on self-report impulsiveness (Barratt Impulsiveness Scale-11, Patton et al., 1995), and performance-based measures of behavioral disinhibition, risky decision-making, and two measures of delay discounting (Kirby et al., 1999; Richards et al., 1999). In both studies, self-injurers reported greater impulsiveness; however, performance-based measures of impulsiveness failed to detect any between-group differences. We propose several potential explanations for the discrepancies observed between self-report and performance-based measures of impulsiveness and discuss directions for future research on impulsiveness and self-injury. PMID:19758706

Similarities and differences among Internet gaming disorder, gambling disorder and alcohol use disorder: A focus on impulsivity and compulsivity

PubMed Central

CHOI, SAM-WOOK; KIM, HYUN SOO; KIM, GA-YOUNG; JEON, YEONGJU; PARK, SU MI; LEE, JUN-YOUNG; JUNG, HEE YEON; SOHN, BO KYOUNG; CHOI, JUNG-SEOK; KIM, DAI-JIN

2014-01-01

Background and aims: The aim of the present study was to test the impulsivities and compulsivities of behavioral addictions, including Internet gaming disorder (IGD) and gambling disorder (GD), by directly comparing them with alcohol use disorder (AUD) and a healthy control (HC) group. Methods: We enrolled male patients who were diagnosed with IGD, GD or AUD, with 15 patients per group, as well as 15 HCs. Trait impulsivity was measured using the Barratt Impulsiveness Scale version 11 (BIS-11). The stop-signal test (SST) from the Cambridge Neuro-psychological Test Automated Battery (CANTAB) was used to assess the patients’ abilities to inhibit prepotent responses. Compulsivity was measured using the intra–extra dimensional set shift (IED) test from the CANTAB. The Trail Making Test (TMT) was also used in this study. Results: The IGD and AUD groups scored significantly higher on the BIS-11 as a whole than did the HC group (p = 0.001 and p = 0.001, respectively). The IGD and AUD groups also scored significantly higher on the BIS-11 as a whole than did the GD group (p = 0.006 and p = 0.001, respectively). In addition, the GD group made significantly more errors (p = 0.017 and p = 0.022, respectively) and more individuals failed to achieve criterion on the IED test compared with the IGD and HC groups (p = 0.018 and p = 0.017, respectively). Discussion: These findings may aid in the understanding of not only the differences in categorical aspects between individuals with IGD and GD but also in impulsivity–compulsivity dimensional domains. Conclusion: Additional studies are needed to elucidate the neurocognitive characteristics of behavioral addictive disorders in terms of impulsivity and compulsivity. PMID:25592310

Electromagnetic propulsion for spacecraft

NASA Technical Reports Server (NTRS)

Myers, Roger M.

1993-01-01

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.

Impulsivity and eating behavior in males

PubMed

Jáuregui-Lobera, Ignacio; Santiago, María José

2017-02-01

Introduction: Impulsivity is a personality trait related with the control of behaviour and emotions and it is found in different psychopathological alterations, including those referred to eating behaviour. Objective: The aim of this study was to analyse the relationship among the infl uence of the aesthetic body shape model, eating behaviour (and risk for specific disorders), body mass index and impulsivity. Method: A total of 178 males were included in the study, with a mean age of 20.18 ± 2.48. Height and weight were assessed in order to obtain the body mass index. All participants fulfilled the following questionnaires: Barratt Impulsivity Scale (BIS-11), Questionnaire of Infl uences on the Body Shape Model for males (CIMEC-V) and the Eating Attitudes Test (EAT-40). Results: With respect to possible cases of eating disorders, 5.06% were found. Scores of some items of BIS-11 correlated significantly with the EAT-40 and CIMEC-V scores. Overweight participants (39.89%) showed higher level of impulsivity as well as those with EAT-40 scores above the cut-off point for that test. Conclusions: The assessment of impulsivity from a psychological point of view might be a preventive tool with regards to disordered eating behaviours. Respecting the patients with eating disorders/overweight/obesity, that assessment might be a relevant aspect in order to improve the therapeutical approach.

Transient vibration analytical modeling and suppressing for vibration absorber system under impulse excitation

NASA Astrophysics Data System (ADS)

Wang, Xi; Yang, Bintang; Yu, Hu; Gao, Yulong

2017-04-01

The impulse excitation of mechanism causes transient vibration. In order to achieve adaptive transient vibration control, a method which can exactly model the response need to be proposed. This paper presents an analytical model to obtain the response of the primary system attached with dynamic vibration absorber (DVA) under impulse excitation. The impulse excitation which can be divided into single-impulse excitation and multi-impulse excitation is simplified as sinusoidal wave to establish the analytical model. To decouple the differential governing equations, a transform matrix is applied to convert the response from the physical coordinate to model coordinate. Therefore, the analytical response in the physical coordinate can be obtained by inverse transformation. The numerical Runge-Kutta method and experimental tests have demonstrated the effectiveness of the analytical model proposed. The wavelet of the response indicates that the transient vibration consists of components with multiple frequencies, and it shows that the modeling results coincide with the experiments. The optimizing simulations based on genetic algorithm and experimental tests demonstrate that the transient vibration of the primary system can be decreased by changing the stiffness of the DVA. The results presented in this paper are the foundations for us to develop the adaptive transient vibration absorber in the future.

Neuropsychological performance, impulsivity, ADHD symptoms, and novelty seeking in compulsive buying disorder.

PubMed

Black, Donald Wayne; Shaw, Martha; McCormick, Brett; Bayless, John David; Allen, Jeff

2012-12-30

We examined the neuropsychological performance of people with compulsive buying disorder (CBD) and control subjects, along with trait impulsivity, symptoms of attention deficit hyperactivity disorder (ADHD), and selected personality characteristics. Subjects received a comprehensive neuropsychological test battery, depression and ADHD symptom assessment, the Barratt Impulsiveness Scale, and a version of the Temperament and Character Inventory. Persons with CBD (n=26) and controls (n=32) were comparable in terms of age, sex, and years of education. Subjects with CBD had a mean age of 36.3 years (S.D.=15.7) and an age at onset of 19.7 years (S.D.=7.0). Compulsive buyers had more lifetime mood, anxiety, and impulse control disorders. People with Compulsive buying performed significantly better on the Wechsler Abbreviated Scale of Intelligence Picture Completion task, a test of visual perception; otherwise, there were no consistent differences in neuropsychological measures. They also had elevated levels of self-reported depression, ADHD symptoms, trait impulsivity, and novelty seeking. In conclusion, compulsive buyers have greater lifetime psychiatric comorbidity than controls, and higher levels of self-rated depression, ADHD symptoms, trait impulsivity, and novelty seeking. The present study does not support the notion that there is a pattern of neuropsychological deficits associated with CBD. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Electro-impulse de-icing testing analysis and design

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.; Schrag, R. L.; Bernhart, W. D.; Friedberg, R. A.

1988-01-01

Electro-Impulse De-Icing (EIDI) is a method of ice removal by sharp blows delivered by a transient electromagnetic field. Detailed results are given for studies of the electrodynamic phenomena. Structural dynamic tests and computations are described. Also reported are ten sets of tests at NASA's Icing Research Tunnel and flight tests by NASA and Cessna Aircraft Company. Fabrication of system components are described and illustrated. Fatigue and electromagnetic interference tests are reported. Here, the necessary information for the design of an EIDI system for aircraft is provided.

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Eric Madaras (left), NASA-Langley Research Center, and Jim McGee, The Boeing Company, Huntington Beach, Calif., conduct impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

NASA Image and Video Library

2003-10-27

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Eric Madaras (left), NASA-Langley Research Center, and Jim McGee, The Boeing Company, Huntington Beach, Calif., conduct impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

Interactive Effects of Cumulative Stress and Impulsivity on Alcohol Consumption

PubMed Central

Fox, Helen C.; Bergquist, Keri L.; Gu, Peihua; Sinha, Rajita

2013-01-01

Background Alcohol addiction may reflect adaptations to stress, reward, and regulatory brain systems. While extensive research has identified both stress and impulsivity as independent risk factors for drinking, few studies have assessed the interactive relationship between stress and impulsivity in terms of hazardous drinking within a community sample of regular drinkers. Methods One hundred and thirty regular drinkers (56M/74F) from the local community were assessed for hazardous and harmful patterns of alcohol consumption using the Alcohol Use Disorders Identification Test (AUDIT). All participants were also administered the Barratt Impulsiveness Scale (BIS-11) as a measure of trait impulsivity and the Cumulative Stress/Adversity Checklist (CSC) as a comprehensive measure of cumulative adverse life events. Standard multiple regression models were used to ascertain the independent and interactive nature of both overall stress and impulsivity as well as specific types of stress and impulsivity on hazardous and harmful drinking. Results Recent life stress, cumulative traumatic stress, overall impulsivity, and nonplanning-related impulsivity as well as cognitive and motor-related impulsivity were all independently predictive of AUDIT scores. However, the interaction between cumulative stress and total impulsivity scores accounted for a significant amount of the variance, indicating that a high to moderate number of adverse events and a high trait impulsivity rating interacted to affect greater AUDIT scores. The subscale of cumulative life trauma accounted for the most variance in AUDIT scores among the stress and impulsivity subscales. Conclusions Findings highlight the interactive relationship between stress and impulsivity with regard to hazardous drinking. The specific importance of cumulative traumatic stress as a marker for problem drinking is also discussed. PMID:20491738

Dynamic model of the force driving kinesin to move along microtubule-Simulation with a model system

NASA Astrophysics Data System (ADS)

Chou, Y. C.; Hsiao, Yi-Feng; To, Kiwing

2015-09-01

A dynamic model for the motility of kinesin, including stochastic-force generation and step formation is proposed. The force driving the motion of kinesin motor is generated by the impulse from the collision between the randomly moving long-chain stalk and the ratchet-shaped outer surface of microtubule. Most of the dynamical and statistical features of the motility of kinesin are reproduced in a simulation system, with (a) ratchet structures similar to the outer surface of microtubule, (b) a bead chain connected to two heads, similarly to the stalk of the real kinesin motor, and (c) the interaction between the heads of the simulated kinesin and microtubule. We also propose an experiment to discriminate between the conventional hand-over-hand model and the dynamic model.

Highly impulsive rats: modelling an endophenotype to determine the neurobiological, genetic and environmental mechanisms of addiction

PubMed Central

Jupp, Bianca; Caprioli, Daniele; Dalley, Jeffrey W.

2013-01-01

Impulsivity describes the tendency of an individual to act prematurely without foresight and is associated with a number of neuropsychiatric co-morbidities, including drug addiction. As such, there is increasing interest in the neurobiological mechanisms of impulsivity, as well as the genetic and environmental influences that govern the expression of this behaviour. Tests used on rodent models of impulsivity share strong parallels with tasks used to assess this trait in humans, and studies in both suggest a crucial role of monoaminergic corticostriatal systems in the expression of this behavioural trait. Furthermore, rodent models have enabled investigation of the causal relationship between drug abuse and impulsivity. Here, we review the use of rodent models of impulsivity for investigating the mechanisms involved in this trait, and how these mechanisms could contribute to the pathogenesis of addiction. PMID:23355644

Determination of Elastic Moduli of Fiber-Resin Composites Using an Impulse Excitation Technique

NASA Technical Reports Server (NTRS)

Viens, Michael J.; Johnson, Jeffrey J.

1996-01-01

The elastic moduli of graphite/epoxy and graphite/cyanate ester composite specimens with various laminate lay-ups was determined using an impulse excitation/acoustic resonance technique and compared to those determined using traditional strain gauge and extensometer techniques. The stiffness results were also compared to those predicted from laminate theory using uniaxial properties. The specimen stiffnesses interrogated ranged from 12 to 30 Msi. The impulse excitation technique was found to be a relatively quick and accurate method for determining elastic moduli with minimal specimen preparation and no requirement for mechanical loading frames. The results of this investigation showed good correlation between the elastic modulus determined using the impulse excitation technique, strain gauge and extensometer techniques, and modulus predicted from laminate theory. The flexural stiffness determined using the impulse excitation was in good agreement with that predicted from laminate theory. The impulse excitation/acoustic resonance interrogation technique has potential as a quality control test.

BMI predicts emotion-driven impulsivity and cognitive inflexibility in adolescents with excess weight.

PubMed

Delgado-Rico, Elena; Río-Valle, Jacqueline S; González-Jiménez, Emilio; Campoy, Cristina; Verdejo-García, Antonio

2012-08-01

Adolescent obesity is increasingly viewed as a brain-related dysfunction, whereby reward-driven urges for pleasurable foods "hijack" response selection systems, such that behavioral control progressively shifts from impulsivity to compulsivity. In this study, we aimed to examine the link between personality factors (sensitivity to reward (SR) and punishment (SP), BMI, and outcome measures of impulsivity vs. flexibility in--otherwise healthy--excessive weight adolescents. Sixty-three adolescents (aged 12-17) classified as obese (n = 26), overweight (n = 16), or normal weight (n = 21) participated in the study. We used psychometric assessments of the SR and SP motivational systems, impulsivity (using the UPPS-P scale), and neurocognitive measures with discriminant validity to dissociate inhibition vs. flexibility deficits (using the process-approach version of the Stroop test). We tested the relative contribution of age, SR/SP, and BMI on estimates of impulsivity and inhibition vs. switching performance using multistep hierarchical regression models. BMI significantly predicted elevations in emotion-driven impulsivity (positive and negative urgency) and inferior flexibility performance in adolescents with excess weight--exceeding the predictive capacity of SR and SP. SR was the main predictor of elevations in sensation seeking and lack of premeditation. These findings demonstrate that increases in BMI are specifically associated with elevations in emotion-driven impulsivity and cognitive inflexibility, supporting a dimensional path in which adolescents with excess weight increase their proneness to overindulge when under strong affective states, and their difficulties to switch or reverse habitual behavioral patterns.

Is impulsivity a common trait in bipolar and unipolar disorders?

PubMed

Henna, Elaine; Hatch, John P; Nicoletti, Mark; Swann, Alan C; Zunta-Soares, Giovana; Soares, Jair C

2013-03-01

  Impulsivity is increased in bipolar and unipolar disorders during episodes and is associated with substance abuse disorders and suicide risk. Impulsivity between episodes predisposes to relapses and poor therapeutic compliance. However, there is little information about impulsivity during euthymia in mood disorders. We sought to investigate trait impulsivity in euthymic bipolar and unipolar disorder patients, comparing them to healthy individuals and unaffected relatives of bipolar disorder patients.   Impulsivity was evaluated by the Barratt Impulsiveness Scale (BIS-11A) in 54 bipolar disorder patients, 25 unipolar disorder patients, 136 healthy volunteers, and 14 unaffected relatives. The BIS-11A mean scores for all four groups were compared through the Games-Howell test for all possible pairwise combinations. Additionally, we compared impulsivity in bipolar and unipolar disorder patients with and without a history of suicide attempt and substance abuse disorder.   Bipolar and unipolar disorder patients scored significantly higher than the healthy controls and unaffected relatives on all measures of the BIS-11A except for attentional impulsivity. On the attentional impulsivity measures there were no differences among the unaffected relatives and the bipolar and unipolar disorder groups, but all three of these groups scored higher than the healthy participant group. There was no difference in impulsivity between bipolar and unipolar disorder subjects with and without suicide attempt. However, impulsivity was higher among bipolar and unipolar disorder subjects with past substance use disorder compared to patients without such a history.   Questionnaire-measured impulsivity appears to be relatively independent of mood state in bipolar and unipolar disorder patients; it remains elevated in euthymia and is higher in individuals with past substance abuse. Elevated attentional and lower non-planning impulsivity in unaffected relatives of bipolar disorder patients distinguished them from healthy participants, suggesting that increased attentional impulsivity may predispose to development of affective disorders, while reduced attentional impulsivity may be protective. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Individual differences in voluntary alcohol intake in rats: relationship with impulsivity, decision making and Pavlovian conditioned approach.

PubMed

Spoelder, Marcia; Flores Dourojeanni, Jacques P; de Git, Kathy C G; Baars, Annemarie M; Lesscher, Heidi M B; Vanderschuren, Louk J M J

2017-07-01

Alcohol use disorder (AUD) has been associated with suboptimal decision making, exaggerated impulsivity, and aberrant responses to reward-paired cues, but the relationship between AUD and these behaviors is incompletely understood. This study aims to assess decision making, impulsivity, and Pavlovian-conditioned approach in rats that voluntarily consume low (LD) or high (HD) amounts of alcohol. LD and HD were tested in the rat gambling task (rGT) or the delayed reward task (DRT). Next, the effect of alcohol (0-1.0 g/kg) was tested in these tasks. Pavlovian-conditioned approach (PCA) was assessed both prior to and after intermittent alcohol access (IAA). Principal component analyses were performed to identify relationships between the most important behavioral parameters. HD showed more optimal decision making in the rGT. In the DRT, HD transiently showed reduced impulsive choice. In both LD and HD, alcohol treatment increased optimal decision making in the rGT and increased impulsive choice in the DRT. PCA prior to and after IAA was comparable for LD and HD. When PCA was tested after IAA only, HD showed a more sign-tracking behavior. The principal component analyses indicated dimensional relationships between alcohol intake, impulsivity, and sign-tracking behavior in the PCA task after IAA. HD showed a more efficient performance in the rGT and DRT. Moreover, alcohol consumption enhanced approach behavior to reward-predictive cues, but sign-tracking did not predict the level of alcohol consumption. Taken together, these findings suggest that high levels of voluntary alcohol intake are associated with enhanced cue- and reward-driven behavior.

Psychometrically Improved, Abbreviated Versions of Three Classic Measures of Impulsivity and Self-Control

PubMed Central

Morean, Meghan E.; DeMartini, Kelly S.; Leeman, Robert F.; Pearlson, Godfrey D.; Anticevic, Alan; Krishnan-Sarin, Suchitra; Krystal, John H.; O’Malley, Stephanie S.

2014-01-01

Self-reported impulsivity confers risk factor for substance abuse. However, the psychometric properties of many self-report impulsivity measures have been questioned, thereby undermining the interpretability of study findings using these measures. To better understand these measurement limitations and to suggest a path to assessing self-reported impulsivity with greater psychometric stability, we conducted a comprehensive psychometric evaluation of the Barratt Impulsiveness Scale-11 (BIS-11), the Behavioral Inhibition and Activation Scales (BIS/BAS), and the Brief Self Control Scale (BSCS) using data from 1,449 individuals who participated in substance use research. For each measure, we evaluated: 1) latent factor structure, 2) measurement invariance, 3) test-criterion relationships between the measures, and 4) test-criterion relations with drinking and smoking outcomes. Notably, we could not replicate the originally published latent structure for the BIS, BIS/BAS, or BSCS or any previously published alternative factor structures (English language). Using exploratory and confirmatory factor analysis, we identified psychometrically improved, abbreviated versions of each measure (i.e., 8-item, 2 factor BIS-11 [RMSEA = .06, CFI = .95]; 13-item, 4 factor BIS/BAS [RMSEA = .04, CFI = .96]; 7-item, 2 factor BSCS [RMSEA = .05, CFI = .96]). These versions evidenced: 1) stable, replicable factor structures, 2) scalar measurement invariance, ensuring our ability to make statistically interpretable comparisons across subgroups of interest (e.g., sex, race, drinking/smoking status), and 3) test-criterion relationships with each other and with drinking/smoking. This study provides strong support for using these psychometrically improved impulsivity measures, which improve data quality directly through better scale properties and indirectly through reducing response burden. PMID:24885848

Vestibular (dys)function in children with sensorineural hearing loss: a systematic review.

PubMed

Verbecque, Evi; Marijnissen, Tessa; De Belder, Niels; Van Rompaey, Vincent; Boudewyns, An; Van de Heyning, Paul; Vereeck, Luc; Hallemans, Ann

2017-06-01

The objective of this study is to provide an overview of the prevalence of vestibular dysfunction in children with SNHL classified according to the applied test and its corresponding sensitivity and specificity. Data were gathered using a systematic search query including reference screening. Pubmed, Web of Science and Embase were searched. Strategy and reporting of this review was based on the Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Methodological quality was assessed with the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist. All studies, regardless the applied vestibular test, showed that vestibular function differs significantly between children with hearing loss and normal hearing (p < 0.05). Compared with caloric testing, the sensitivity of the Rotational Chair Test (RCT) varies between 61 and 80% and specificity between 21 and 80%, whereas this was, respectively, 71-100% and 30-100% for collic Vestibular Evoked Myogenic Potentials (cVEMP). Compared with RCT, the sensitivity was 88-100% and the specificity was 69-100% for the Dynamic Visual Acuity test, respectively, 67-100% and 71-100% for the (video) Head Impulse Test and 83% and 86% for the ocular VEMP. Currently, due to methodological shortcoming, evidence on sensitivity and specificity of vestibular tests is unknown to moderate. Future research should focus on adequate sample sizes (subgroups >30).

Food craving, food choice and consumption: The role of impulsivity and sham-controlled tDCS stimulation of the right dlPFC.

PubMed

Georgii, Claudio; Goldhofer, Philipp; Meule, Adrian; Richard, Anna; Blechert, Jens

2017-08-01

Impulsivity has been found to be associated with overeating and obesity. Transcranial direct current stimulation (tDCS) may enhance inhibitory control while reducing food craving and intake. Thus, the aim of the present study was to investigate whether tDCS stimulation modifies food choice, craving and consumption as a function of trait impulsivity. Forty-two predominantly healthy-weight women received active tDCS stimulation to the right dorsolateral prefrontal cortex and sham stimulation in a within participant design. Trait impulsivity was measured with a short form of the Barratt Impulsiveness Scale. Participants completed a computerized food-choice task, during which their mouse movements were traced. Current food craving was measured by a modified version of the Food Cravings Questionnaire-State as well as by desire to eat ratings for food pictures. Food intake was measured in a taste test. There were no tDCS effects on any of the dependent variables. Trait impulsivity (and non-planning impulsivity in particular) was positively associated with higher calorie intake in the taste test, irrespective of tDCS stimulation. The current findings question the efficacy of single-session tDCS stimulation of the right dLPFC to reduce food craving, high caloric food choice and calorie intake in non-selected, predominantly healthy weight women. However, they do support the idea that trait impulsivity is related to overeating and, therefore, may be a risk factor for obesity. Future research needs to specify which appetitive behaviors can be modulated by brain stimulation and which populations might profit from it the most. Copyright © 2017 Elsevier Inc. All rights reserved.

ADHD symptoms in non-treatment seeking young adults: relationship with other forms of impulsivity.

PubMed

Chamberlain, Samuel R; Ioannidis, Konstantinos; Leppink, Eric W; Niaz, Faiza; Redden, Sarah A; Grant, Jon E

2017-02-01

Attention-deficit hyperactivity disorder (ADHD) has been associated with various manifestations of impulsivity in adults, including elevated rates of other impulsive disorders, substance use, questionnaire-based impulsivity scores, and inhibitory dysregulation on neurocognitive tests. The relationship between ADHD and all these other forms of impulsivity has yet to be explored within the context of a single comprehensive study. A total of 423 young adults, who gambled ≥5 times in the preceding year, were recruited using media advertisements and undertook detailed assessment including structured psychiatric interview, questionnaires, and neurocognitive tests. Participants with ADHD symptoms were identified using the Adult ADHD Self-Report Scale Screener (ASRS-V1.1) and were compared to controls using multivariate analysis of variance (MANOVA). ADHD symptoms were found in 20.3% of the sample, but only 7.3% of these subjects had ever received a formal diagnosis. ADHD symptoms were associated with significantly lower quality of life, lower self-esteem, higher emotional dysregulation, higher impulsivity questionnaire scores, more problematic Internet use, greater occurrence of psychiatric disorders, and impaired stop-signal reaction times. Of these variables, stop-signal reaction times and Barratt attentional impulsiveness were the strongest predictors of group classification. ADHD symptoms are common and under-diagnosed in young adults who gamble, and are most strongly linked with certain other types of impulsivity (questionnaire- and cognitive-based measures) and with emotional dysregulation, suggesting that these are each important considerations in understanding the pathophysiology of the disorder, but also potential treatment targets. It is necessary to question whether treatment for adult ADHD could be enhanced by considering self-esteem, emotional reactivity, and impaired inhibitory control as specific treatment targets, in addition to the core diagnostic symptoms of the disorder.

29. At 1050 Gallery, Block 12, two centrifugal pumps, Buffalo ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. At 1050 Gallery, Block 12, two centrifugal pumps, Buffalo Pumps, Buffalo, NY, driven by Allis Chalmers motors (size 3 HSO, head 230, 120 cpm, 1750, rpm, Impulse dia. 15) installed in the 1960s and used for water-cooling system for 230-kv cable; the cables have been removed and the pumps are not currently used. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

Integrative Understanding of Familial Impulsivity, Early Adversity and Suicide Risk.

PubMed

Lima, Isabela M M; Malloy-Diniz, Leandro F; de Miranda, Débora M; Da Silva, Antônio G; Neves, Fernando S; Johnson, Sheri L

2017-01-01

Introduction: Impulsivity is a core characteristic of bipolar disorder and it was observed as elevated in individuals with the disorder and in their relatives. Both impulsivity and history of maltreatment are risk factors for suicide attempts, however, these two key variables may not be independent, given the fact that parental impulsivity and associated social context could increase the risk of child maltreatment. In this study it was examined the association between the impulsivity of relatives and child maltreatment taking into consideration the conjoint and unique effects of these two variables on the risk of suicide attempts among the patients. Materials and Methods: Participants of the study consisted of 117 patients diagnosed with bipolar disorder and 25 first-degree relatives. Linear regression model was conducted to describe associations between facets of impulsivity of relatives and levels of child maltreatment reported by patients. The independent associations of suicide attempt history with the dimensions of impulsivity of the patient and maltreatment were tested by multinomial logistic regression. Results: Impulsivity of relatives and, more specifically, inhibitory control can predict the maltreatment of the patient. Inhibitory control and emotional abuse were related, conjointly, to a greater likelihood of having a history of more than one suicide attempt. Discussion: Considering that the impulsivity of relatives predicts child maltreatment, it is possible that a genetically shared impulsivity is an underlying feature associated with the history of multiple suicide attempts. These findings highlight the importance of considering child maltreatment, impulsivity and suicide attempt history in integrative models.

Integrative Understanding of Familial Impulsivity, Early Adversity and Suicide Risk

PubMed Central

Lima, Isabela M. M.; Malloy-Diniz, Leandro F.; de Miranda, Débora M.; Da Silva, Antônio G.; Neves, Fernando S.; Johnson, Sheri L.

2017-01-01

Introduction: Impulsivity is a core characteristic of bipolar disorder and it was observed as elevated in individuals with the disorder and in their relatives. Both impulsivity and history of maltreatment are risk factors for suicide attempts, however, these two key variables may not be independent, given the fact that parental impulsivity and associated social context could increase the risk of child maltreatment. In this study it was examined the association between the impulsivity of relatives and child maltreatment taking into consideration the conjoint and unique effects of these two variables on the risk of suicide attempts among the patients. Materials and Methods: Participants of the study consisted of 117 patients diagnosed with bipolar disorder and 25 first-degree relatives. Linear regression model was conducted to describe associations between facets of impulsivity of relatives and levels of child maltreatment reported by patients. The independent associations of suicide attempt history with the dimensions of impulsivity of the patient and maltreatment were tested by multinomial logistic regression. Results: Impulsivity of relatives and, more specifically, inhibitory control can predict the maltreatment of the patient. Inhibitory control and emotional abuse were related, conjointly, to a greater likelihood of having a history of more than one suicide attempt. Discussion: Considering that the impulsivity of relatives predicts child maltreatment, it is possible that a genetically shared impulsivity is an underlying feature associated with the history of multiple suicide attempts. These findings highlight the importance of considering child maltreatment, impulsivity and suicide attempt history in integrative models. PMID:29312082

Interacting Mechanisms of Impulsivity in Bipolar Disorder and Antisocial Personality Disorder

PubMed Central

Swann, Alan C.; Lijffijt, Marijn; Lane, Scott D.; Steinberg, Joel L.; Moeller, F. Gerard

2011-01-01

Background Bipolar disorder and antisocial personality disorder (ASPD) overlap in clinical characteristics and behavioral consequences. Impulsivity is prominent in both, but there is little information on how specific mechanisms of impulsivity differentiate, bridge, or underlie the disorders. Methods Subjects, all males, were controls (n=46), bipolar disorder without cluster B personality disorder (n=21), ASPD without bipolar disorder (n=50), and bipolar disorder with ASPD (n=16). Impulsivity measures were the Immediate Memory Task (IMT), a continuous performance test of response inhibition measuring ability to evaluate a stimulus before responding, and the Two Choice Impulsivity Paradigm (TCIP), a choice between smaller-sooner and larger-later reward. Data were analyzed using general linear models analysis. Results Subjects with bipolar disorder had fewer IMT correct detections and slower reaction times than controls. Reaction times were faster with combined diagnoses than in bipolar disorder alone. TCIP responding in either diagnosis alone resembled controls, but was more impulsive in combined disorders. These differences persisted after correction for age and education, which had significant independent effects. In combined ASPD and bipolar disorder, increased reaction speed, impulsive response bias, and reward-delay impulsivity occurred independent of substance-use disorder history. Conclusions Impulsivity was increased in the combined disorders over either disorder alone. Results were consistent with at least partially distinct mechanisms of impulsivity in ASPD and bipolar disorder. Compensatory mechanisms for impulsivity in uncomplicated ASPD or bipolar disorder appear to be compromised or lost when the disorders are combined. PMID:21719028

An Analysis of the Associations among Cognitive Impulsiveness, Reasoning Process, and Rational Decision Making

PubMed Central

Jelihovschi, Ana P. G.; Cardoso, Ricardo L.; Linhares, Alexandre

2018-01-01

Impulsivity may lead to several unfortunate consequences and maladaptive behaviors for both clinical and nonclinical people. It has a key role in many forms of psychopathology. Although literature has discussed the negative impact of impulsivity, few have emphasized the relationship between cognitive impulsiveness and decision making. The aim of this study is to investigate the effects of cognitive impulsiveness on decision making and explore the strategies used by participants to solve problems. For this purpose, we apply two measures of impulsivity: the self-report Barratt Impulsiveness Scale (BIS-11) and the performance based Cognitive Reflection Test (CRT). Moreover, we evaluate participants' reasoning processes employed to answer CRT questions based on the calculation expressions, data organization, and erasures they made while answering the CRT (note that we utilized the instruments using pen and paper). These reasoning processes are related to the role of executive functions in decision making, and its relationship with impulsiveness. The sample consists of 191 adults, who were either professionals or undergraduate students from the fields of business, management, or accounting. The results show that cognitive impulsiveness may negatively affect decision making, and that those who presented the calculation to answer the CRT questions made better decisions. Moreover, there was no difference in the strategies used by impulsive vs. nonimpulsive participants during decision making. Finally, people who inhibited their immediate answers to CRT questions performed better during decision making. PMID:29375440

An Analysis of the Associations among Cognitive Impulsiveness, Reasoning Process, and Rational Decision Making.

PubMed

Jelihovschi, Ana P G; Cardoso, Ricardo L; Linhares, Alexandre

2017-01-01

Impulsivity may lead to several unfortunate consequences and maladaptive behaviors for both clinical and nonclinical people. It has a key role in many forms of psychopathology. Although literature has discussed the negative impact of impulsivity, few have emphasized the relationship between cognitive impulsiveness and decision making. The aim of this study is to investigate the effects of cognitive impulsiveness on decision making and explore the strategies used by participants to solve problems. For this purpose, we apply two measures of impulsivity: the self-report Barratt Impulsiveness Scale (BIS-11) and the performance based Cognitive Reflection Test (CRT). Moreover, we evaluate participants' reasoning processes employed to answer CRT questions based on the calculation expressions, data organization, and erasures they made while answering the CRT (note that we utilized the instruments using pen and paper). These reasoning processes are related to the role of executive functions in decision making, and its relationship with impulsiveness. The sample consists of 191 adults, who were either professionals or undergraduate students from the fields of business, management, or accounting. The results show that cognitive impulsiveness may negatively affect decision making, and that those who presented the calculation to answer the CRT questions made better decisions. Moreover, there was no difference in the strategies used by impulsive vs. nonimpulsive participants during decision making. Finally, people who inhibited their immediate answers to CRT questions performed better during decision making.

THE RELATIONSHIP BETWEEN MEASURES OF IMPULSIVITY AND ALCOHOL MISUSE: AN INTEGRATIVE STRUCTURAL EQUATION MODELING APPROACH

PubMed Central

Courtney, Kelly E.; Arellano, Ryan; Barkley-Levenson, Emily; Gálvan, Adriana; Poldrack, Russell A.; MacKillop, James; Jentsch, J. David; Ray, Lara A.

2011-01-01

Background Higher levels of impulsivity have been implicated in the development of alcohol use disorders. Recent findings suggest that impulsivity is not a unitary construct, highlighted by the diverse ways in which the various measures of impulsivity relate to alcohol use outcomes. This study simultaneously tested the following dimensions of impulsivity as determinants of alcohol use and alcohol problems: risky decision-making, self-reported risk attitudes, response inhibition, and impulsive decision-making. Method Participants were a community sample of non-treatment seeking problem drinkers (N = 158). Structural Equation Modeling (SEM) analyses employed behavioral measures of impulsive decision-making (Delay Discounting Task, DDT), response inhibition (Stop Signal Task, SST), and risky decision-making (Balloon Analogue Risk Task, BART), and a self-report measure of risk attitudes (Domain-specific Risk-attitude Scale, DOSPERT), as predictors of alcohol use and of alcohol-related problems in this sample. Results The model fit well, accounting for 38% of the variance in alcohol problems, and identified two impulsivity dimensions that significantly loaded onto alcohol outcomes: (1) impulsive decision-making, indexed by the DDT; and (2) risky decision-making, measured by the BART. Conclusions The impulsive decision-making dimension of impulsivity, indexed by the DDT, was the strongest predictor of alcohol use and alcohol pathology in this sample of problem drinkers. Unexpectedly, a negative relationship was found between risky decision-making and alcohol problems. The results highlight the importance of considering the distinct facets of impulsivity in order to elucidate their individual and combined effects on alcohol use initiation, escalation, and dependence. PMID:22091877

An Impulse Based Substructuring approach for impact analysis and load case simulations

NASA Astrophysics Data System (ADS)

Rixen, Daniel J.; van der Valk, Paul L. C.

2013-12-01

In the present paper we outline the basic theory of assembling substructures for which the dynamics are described as Impulse Response Functions. The assembly procedure computes the time response of a system by evaluating per substructure the convolution product between the Impulse Response Functions and the applied forces, including the interface forces that are computed to satisfy the interface compatibility. We call this approach the Impulse Based Substructuring method since it transposes to the time domain the Frequency Based Substructuring approach. In the Impulse Based Substructuring technique the Impulse Response Functions of the substructures can be gathered either from experimental tests using a hammer impact or from time-integration of numerical submodels. In this paper the implementation of the method is outlined for the case when the impulse responses of the substructures are computed numerically. A simple bar example is shown in order to illustrate the concept. The Impulse Based Substructuring allows fast evaluation of impact response of a structure when the impulse response of its components is known. It can thus be used to efficiently optimize designs of consumer products by including impact behavior at the early stage of the design, but also for performing substructured simulations of complex structures such as offshore wind turbines.

Impulsivity and Clinical Symptoms among Adolescents with Non-Suicidal Self-Injury with or without Attempted Suicide

PubMed Central

Dougherty, Donald M.; Mathias, Charles W.; Marsh-Richard, Dawn M.; Prevette, Kristen N.; Dawes, Michael A.; Hatzis, Erin S.; Palmes, Guy; Nouvion, Sylvain O.

2011-01-01

This study examined clinical characteristics and laboratory-measured impulsive behavior of adolescents engaging in either non-suicidal self-injury with (NSSI+SA; n = 25) or without (NSSI-Only; n = 31) suicide attempts. We hypothesized that adolescent with NSSI+SI would exhibit more severe clinical symptoms and higher levels of behavioral impulsivity compared to adolescents with NSSI-Only. Adolescents were recruited from an inpatient psychiatric hospital unit and the two groups were compared on demographic characteristics, psychopathology, self-reported clinical ratings, methods of non-suicidal self-injury, and two laboratory impulsivity measures. Primary evaluations were conducted during psychiatric hospitalization, and a subset of those tested during hospitalization was retested 4-6 weeks after discharge. During hospitalization, NSSI+SA patients reported worse depression, hopelessness, and impulsivity on standard clinical measures, and demonstrated elevated impulsivity on a reward-directed laboratory measure compared to NSSI-Only patients. In the preliminary follow-up analyses, depression, hopelessness, suicidal ideation, and laboratory impulsivity were improved for both groups, but the NSSI+SA group still exhibited significantly more depressive symptoms, hopelessness, and impulsivity than the NSSI-Only group. Risk assessments for adolescents with NSSI+SA should include consideration not only of the severity of clinical symptoms but of the current level impulsivity as well. PMID:19631392

Nonsuicidal self-injury: relationship to behavioral and self-rating measures of impulsivity and self-aggression.

PubMed

McCloskey, Michael S; Look, Amy E; Chen, Eunice Y; Pajoumand, Golnaz; Berman, Mitchell E

2012-04-01

Previous research using self-report measures has shown an association between nonsuicidal self-injurious behavior (NSSI) and impulsive tendencies. However, self-injurers have not been shown to be different from comparison groups on laboratory tasks putatively assessing impulsive behavior. One explanation for these contradictory findings is that self-report and laboratory measures of impulsive behavior tap into distinct but related constructs. Moreover, performance on laboratory measures of impulsive behavior can be influenced by myriad contextual and affective factors not present during past self-reported NSSI events. Accordingly, a relationship between behavioral tasks of impulsivity and self-injurious behavior could emerge if both are assessed relatively close in time under controlled laboratory conditions. To test this possibility, both self-ratings and laboratory task measures of self-injurious and impulsive behavior were employed in the current study. This multi-modal assessment approach revealed that self-rated impulsivity was associated with both self-report and behavioral measures of self-injurious behavior. Moreover, behavioral measures of impulsivity were associated with self-injurious behavior, but not NSSI history. These results provide support for the notion that a multi-modal approach to assessing self-injurious behavior is important for better understanding the correlates of nonsuicidal self-injury. © 2012 The American Association of Suicidology.

Impulsivity and clinical symptoms among adolescents with non-suicidal self-injury with or without attempted suicide.

PubMed

Dougherty, Donald M; Mathias, Charles W; Marsh-Richard, Dawn M; Prevette, Kristen N; Dawes, Michael A; Hatzis, Erin S; Palmes, Guy; Nouvion, Sylvain O

2009-08-30

This study examined clinical characteristics and laboratory-measured impulsive behavior of adolescents engaging in either non-suicidal self-injury with (NSSI+SA; n=25) or without (NSSI-Only; n=31) suicide attempts. We hypothesized that adolescent with NSSI+SI would exhibit more severe clinical symptoms and higher levels of behavioral impulsivity compared to adolescents with NSSI-Only. Adolescents were recruited from an inpatient psychiatric hospital unit and the two groups were compared on demographic characteristics, psychopathology, self-reported clinical ratings, methods of non-suicidal self-injury, and two laboratory impulsivity measures. Primary evaluations were conducted during psychiatric hospitalization, and a subset of those tested during hospitalization was retested 4-6 weeks after discharge. During hospitalization, NSSI+SA patients reported worse depression, hopelessness, and impulsivity on standard clinical measures, and demonstrated elevated impulsivity on a reward-directed laboratory measure compared to NSSI-Only patients. In the follow-up analyses, depression, hopelessness, suicidal ideation, and laboratory impulsivity were improved for both groups, but the NSSI+SA group still exhibited significantly more depressive symptoms, hopelessness, and impulsivity than the NSSI-Only group. Risk assessments for adolescents with NSSI+SA should include consideration not only of the severity of clinical symptoms but of the current level impulsivity as well.

Cognitive impulsivity and the development of delinquency from late childhood to early adulthood: Moderating effects of parenting behavior and peer relationships.

PubMed

Menting, Barbara; Van Lier, Pol A C; Koot, Hans M; Pardini, Dustin; Loeber, Rolf

2016-02-01

Cognitive impulsivity may increase children's risk of developing delinquent behavior. However, the influence of cognitive impulsivity may depend on social environmental risk factors. This study examined the moderating effect of late childhood parenting behaviors and peer relations on the influence of children's cognitive impulsivity on delinquency development across adolescence and early adulthood, while taking possible interactions with intelligence also into account. Delinquent behavior of 412 boys from the Pittsburgh Youth Study was measured annually from ages 13 to 29 years with official arrest records. Cognitive impulsivity (neurocognitive test scores) and intelligence were assessed at age 12-13. Parenting behaviors (persistence of discipline, positive reinforcement, and parental knowledge), peer delinquency, and peer conventional activities were assessed between ages 10 and 13 years. Results showed that, while controlling for intelligence, the influence of youths' cognitive impulsivity on delinquency depended on their parents' behaviors. An interaction was found among cognitive impulsivity, intelligence, and peer delinquency, but instead of cognitive impulsivity, the effect of intelligence on delinquency was particularly moderated. Overall, findings suggest that when there was moderation, high cognitive impulsivity and low intelligence were associated with an increased probability for engaging in delinquency predominantly among boys in a good social environment, but not in a poor social environment.

Being impulsive and obese increases susceptibility to speeded detection of high-calorie foods.

PubMed

Bongers, Peggy; van de Giessen, Elsmarieke; Roefs, Anne; Nederkoorn, Chantal; Booij, Jan; van den Brink, Wim; Jansen, Anita

2015-06-01

Overeating and obesity are associated with impulsivity. In studies among patients with a substance use disorder, impulsivity was found to be associated with substance-related attentional bias. This study examined whether obesity, impulsivity and food craving are associated with an attentional bias for high-calorie food. Obese (n = 185, mean BMI = 38.18 ± 6.17) and matched healthy-weight (n = 134, mean BMI = 22.35 ± 1.63) men (27.9%) and women (72.1%), aged 18-45 years, took part in the study. Participants were tested on several self-report and behavioral measures of impulsivity (i.e., response inhibition and reward sensitivity) and self-reported trait craving. In addition, they performed a visual search task to measure attentional bias for high- and low-caloric foods. Self-reported impulsivity influenced the relationship between weight status and detection speed of high- and low-caloric food items: High-impulsive participants with obesity were significantly faster than high-impulsive healthy-weight participants in detecting a high-caloric food item among neutral items, whereas no such difference was observed among low-impulsive participants. No significant effects were found on low-caloric food items, for trait craving or any of the behavioral measures of impulsivity. Self-reported impulsivity, but not trait craving or behavioral measures of impulsivity, is associated with an attentional bias for high-caloric foods, but only in people with obesity. It is in particular the speedy detection of high-caloric foods in the environment that characterizes the impulsive person with obesity, which in turn may cause risky eating patterns in a society were high-caloric food is overly present. (c) 2015 APA, all rights reserved).

Dopaminergic modulation of the orbitofrontal cortex affects attention, motivation and impulsive responding in rats performing the five-choice serial reaction time task.

PubMed

Winstanley, Catharine A; Zeeb, Fiona D; Bedard, Amanda; Fu, Kent; Lai, Barbara; Steele, Christina; Wong, Adeline C

2010-07-11

Understanding the neurobiological factors underlying individual differences in impulsivity may provide valuable insight into vulnerability to impulse control disorders. Recent data implicate both the orbitofrontal cortex (OFC) and the dopaminergic system in psychiatric disorders associated with high levels of impulsivity, including substance abuse, mania and obsessive-compulsive disorder. However, the consequences of modulating dopaminergic activity within the OFC on impulsive behaviour are largely unknown. The effects of direct intra-OFC infusions of agonists and antagonists at the dopamine D(1) and D(2) receptors were therefore assessed in rats performing the five-choice serial reaction time test (5CSRT) of attention and motor impulsivity. Intra-OFC administration of SCH23390, a D(1) receptor antagonist, decreased impulsive responding in highly impulsive (HI) rats, but did not affect behaviour in less impulsive (LI) animals. Furthermore, the D(2) agonist quinpirole caused significant deficits in task performance, impairing accuracy, increasing omissions and decreasing the number of trials completed, which resembled the effects of systemic administration. In contrast, the D(1) agonist SKF 81297 had little effect on behaviour. Neither agonist increased impulsivity. These data provide partial support for the suggestion that high levels of impulsivity are associated with increased dopamine levels within the OFC, but further indicate that simulating dopamine's actions selectively at the D(1) or D(2) receptor cannot reproduce a highly impulsive phenotype. Dopaminergic activity within the OFC may therefore modulate impulsivity indirectly, perhaps in conjunction with other neurotransmitter systems. Furthermore, D(2)-mediated neurotransmission within the OFC could make a more fundamental contribution to cognitive behaviour. Copyright 2010 Elsevier B.V. All rights reserved.

Chronic Traumatic Encephalopathy: A Potential Late Effect of Sport-Related Concussive and Subconcussive Head Trauma1

PubMed Central

Gavett, Brandon E.; Stern, Robert A.; McKee, Ann C.

2010-01-01

Synopsis Chronic traumatic encephalopathy (CTE) is a form of neurodegeneration that is believed to result from repeated head injuries. Originally termed dementia pugilistica due to its association with boxing, the neuropathology of CTE was first described by Corsellis in 1973 in a case series of 15 retired boxers. CTE has recently been found to occur following other causes of repeated head trauma, suggesting that any repeated blows to the head, such as those that occur due to American football, hockey, soccer, professional wrestling, and physical abuse, can also lead to neurodegenerative changes. These changes often include cerebral atrophy, cavum septum pellucidum with fenestrations, shrinkage of the mammillary bodies, dense tau immunoreactive inclusions (neurofibrillary tangles, glial tangles, and neuropil neurites), diffuse axonal injury, and, in some cases, a TDP-43 proteinopathy. In association with these pathological changes, affected individuals often exhibit disordered memory and executive functioning, behavioral and personality disturbances (e.g., apathy, depression, irritability, impulsiveness, suicidality), parkinsonism, and, occasionally, motor neuron disease. At the present time, there are no formal clinical or pathological diagnostic criteria for CTE, but the distinctive neuropathological profile of the disorder lends promise for future research into its prevention, diagnosis, and treatment. PMID:21074091

Occupant kinematics in low-speed frontal sled tests: Human volunteers, Hybrid III ATD, and PMHS.

PubMed

Beeman, Stephanie M; Kemper, Andrew R; Madigan, Michael L; Franck, Christopher T; Loftus, Stephen C

2012-07-01

A total of 34 dynamic matched frontal sled tests were performed, 17 low (2.5g, Δv=4.8kph) and 17 medium (5.0g, Δv=9.7kph), with five male human volunteers of approximately 50th percentile height and weight, a Hybrid III 50th percentile male ATD, and three male PMHS. Each volunteer was exposed to two impulses at each severity, one relaxed and one braced prior to the impulse. A total of four tests were performed at each severity with the ATD and one trial was performed at each severity with each PMHS. A Vicon motion analysis system, 12 MX-T20 2 megapixel cameras, was used to quantify subject 3D kinematics (±1mm) (1kHz). Excursions of select anatomical regions were normalized to their respective initial positions and compared by test condition and between subject types. The forward excursions of the select anatomical regions generally increased with increasing severity. The forward excursions of relaxed human volunteers were significantly larger than those of the ATD for nearly every region at both severities. The forward excursions of the upper body regions of the braced volunteers were generally significantly smaller than those of the ATD at both severities. Forward excursions of the relaxed human volunteers and PMHSs were fairly similar except the head CG response at both severities and the right knee and C7 at the medium severity. The forward excursions of the upper body of the PMHS were generally significantly larger than those of the braced volunteers at both severities. Forward excursions of the PMHSs exceeded those of the ATD for all regions at both severities with significant differences within the upper body regions. Overall human volunteers, ATD, and PMHSs do not have identical biomechanical responses in low-speed frontal sled tests but all contribute valuable data that can be used to refine and validate computational models and ATDs used to assess injury risk in automotive collisions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antisocial personality and bipolar disorder: interactions in impulsivity and course of illness

PubMed Central

Swann, Alan C

2011-01-01

SUMMARY Antisocial personality disorder (ASPD) and bipolar disorder are both characterized by impulsive behavior, increased incarceration or arrest, addictive disorders and suicidal behavior. These characteristics appear more severe in the combined disorders. Individuals with ASPD who also have bipolar disorder have higher rates of addictive disorders and suicidal behavior and are more impulsive, as measured by questionnaires or behavioral laboratory tests. Those with bipolar disorder who have ASPD have higher rates of addictive, criminal and suicidal behavior, earlier onset of bipolar disorder with a more recurrent and predominately manic course and increased laboratory-measured, but not questionnaire-rated, impulsivity. These characteristics may result in part from differential impulsivity mechanisms in the two disorders, with bipolar disorder driven more by excessive catecholamine sensitivity and ASPD by deficient serotonergic function. PMID:22235235

Lithium, but not Valproate, Reduces Impulsive Choice in the Delay-Discounting Task in Mice

PubMed Central

Halcomb, Meredith E; Gould, Todd D; Grahame, Nicholas J

2013-01-01

Both lithium and valproate are well-established treatments for bipolar disorder. Studies have also found that lithium is effective at reducing suicidal behaviors in patients with mood disorders. Impulsivity is a validated endophenotype of both bipolar disorder and suicidal behavior. We assessed effects of treatment with lithium or valproate on cognitive impulsivity in selectively bred mice previously shown to manifest relatively high levels of cognitive impulsivity. Mice were trained in the delay-discounting paradigm, a measure of cognitive impulsivity reflecting a behavioral bias towards immediacy, and then treated with lithium, valproate, or control chow. After 3 weeks of drug treatment, mice were tested at various delays to a large, delayed reward. Drug treatment continued during this time. Lithium reduced impulsivity, whereas valproate had no effect on choice behavior. Both drugs increased the number of choice trials and reinforcer intake, but effects on choice behavior did not depend on these motivational changes. To our knowledge, this is the first study demonstrating lithium's effects to reduce cognitive impulsivity. Future studies may focus on the ability of putative pharmacotherapies for patients at risk for bipolar disorder or suicide to modify the impulsive choice dimension of this diseases. PMID:23584261

'Speedy action over goal orientation': cognitive impulsivity in male forensic patients with dyslexia.

PubMed

Dåderman, Anna M; Meurling, Ann Wirsén; Levander, Sten

2012-11-01

Previous neuropsychiatric studies suggest a relationship between reading disability and cognitive impulsivity. This relationship is not entirely explained by the high comorbidity between reading disability and attention deficit hyperactivity disorder (ADHD), as children with a co-occurrence of these disorders tend to be more impulsive than those with ADHD only. Other research has demonstrated that poor verbal skill (irrespective of the presence of dyslexia) deficits in executive functions and impulsivity are important risk factors for criminal behaviour. The present study bridges these two research traditions by examining whether patients undergoing forensic psychiatric investigation who also have dyslexia, have a cognitive style characterized by impulsivity. Male forensic patients (mean age 27 years, range 16-35) with (n = 9) and without (n = 13) dyslexia were evaluated on the computerized EuroCog test battery. The findings suggest that patients with dyslexia tend to use a cognitive impulsive style and suggest a more direct link between dyslexia and cognitive impulsivity that is not mediated by the presence of ADHD. In order to identify treatment needs and tailor treatment accordingly, forensic patients should be assessed with respect to poor verbal skill, dyslexia and impulsivity. Copyright © 2012 John Wiley & Sons, Ltd.

Spatio-temporal variation in groundwater head affected by stratigraphic heterogeneity of the alluvial aquifer in Northwest India

NASA Astrophysics Data System (ADS)

van Dijk, W. M.; Joshi, S. K.; Densmore, A. L.; Jackson, C. R.; Sutanudjaja, E.; Lafare, A. E. A.; Gupta, S.; Mackay, J. D.; Mason, P. J.; Sinha, R.

2017-12-01

Groundwater is a primary source of freshwater in the alluvial aquifer system of northwestern India. Unsustainable exploitation of the groundwater resources has led to a regional hotspot in groundwater depletion. Rapid groundwater-level decline shows spatial variation, as the effects of various stresses, including precipitation, potential evapotranspiration and abstraction, are likely to be influenced by the stratigraphic and geomorphic heterogeneity between sediment fan and interfan areas (see Geomorphological map in Figure A). We used a transfer function-noise (TFN) time series approach to quantify the effect of the various stress components in the period 1974-2010, based on predefined impulse response functions (IRFs) of von Asmuth et al. (2008). The objective of this study was 1) to acquire the impulse response function of various stresses, 2) assess the spatial estimation parameter (the zeroth moment, M0) of the spatial development of the groundwater head and 3) relate the spatial M0 to the observed stratigraphic and geomorphic heterogeneity. We collected information on the groundwater head pre- and post-monsoon, the district-wise monthly precipitation and potential evapotranspiration, and we modeled the monthly abstraction rate using land-use information. The TFN identified the IRF of precipitation as well as abstraction. The IRF, summarized in the parameter M0, identified a hotspot for the abstraction stress (see M0 spatial map for abstraction in Figure B) at the margins of the Sutlej and Yamuna fans. No hotspot is observed for the precipitation stress, but the M0 for precipitation increases with distance from the Himalayan front. At larger distances from the Himalayan front, observed groundwater head rises cannot be explained by the IRFs for the abstraction and precipitation stresses. This is likely because the current TFN models do not account for other stresses, such as recharge by canal leakage, which are locally important. We conclude that the spatial variation in the M0 for abstraction is controlled by stratigraphic and geomorphic heterogeneity. The fan margins and the interfan area are more affected by abstraction as these areas are underlain by fewer, and thinner, aquifer bodies them the fans themselves. Von Ashmuth et al,2008. Ground Water, 46 (1), 30-40

Teacher Perceptions of the Classroom Behavior of Reflective and Impulsive Children

ERIC Educational Resources Information Center

McKinney, James D.

1975-01-01

Four second-grade teachers completed the Classroom Behavior Inventory for every student in their class (N=101). Subjects were classified as either reflective (N=32) or impulsive (N=32) by using the Matching Familiar Figures Test (MFF). (Author)

Blast from pressurized carbon dioxide released into a vented atmospheric chamber

NASA Astrophysics Data System (ADS)

Hansen, P. M.; Gaathaug, A. V.; Bjerketvedt, D.; Vaagsaether, K.

2018-03-01

This study describes the blast from pressurized carbon dioxide (CO2) released from a high-pressure reservoir into an openly vented atmospheric chamber. Small-scale experiments with pure vapor and liquid/vapor mixtures were conducted and compared with simulations. A motivation was to investigate the effects of vent size and liquid content on the peak overpressure and impulse response in the atmospheric chamber. The comparison of vapor-phase CO2 test results with simulations showed good agreement. This numerical code described single-phase gas dynamics inside a closed chamber, but did not model any phase transitions. Hence, the simulations described a vapor-only test into an unvented chamber. Nevertheless, the simulations reproduced the incident shock wave, the shock reflections, and the jet release inside the atmospheric chamber. The rapid phase transition did not contribute to the initial shock strength in the current test geometry. The evaporation rate was too low to contribute to the measured peak overpressure that was in the range of 15-20 kPa. The simulation results produced a calculated peak overpressure of 12 kPa. The liquid tests showed a significantly higher impulse compared to tests with pure vapor. Reducing the vent opening from 0.1 to 0.01 m2 resulted in a slightly higher impulse calculated at 100 ms. The influence of the vent area on the calculated impulse was significant in the vapor-phase tests, but not so clear in the liquid/vapor mixture tests.

An analysis of regional cerebral blood flow in impulsive murderers using single photon emission computed tomography.

PubMed

Amen, Daniel G; Hanks, Chris; Prunella, Jill R; Green, Aisa

2007-01-01

The authors explored differences in regional cerebral blood flow in 11 impulsive murderers and 11 healthy comparison subjects using single photon emission computed tomography. The authors assessed subjects at rest and during a computerized go/no-go concentration task. Using statistical parametric mapping software, the authors performed voxel-by-voxel t tests to assess significant differences, making family-wide error corrections for multiple comparisons. Murderers were found to have significantly lower relative rCBF during concentration, particularly in areas associated with concentration and impulse control. These results indicate that nonemotionally laden stimuli may result in frontotemporal dysregulation in people predisposed to impulsive violence.

Antecedents of Attention-Deficit/Hyperactivity Disorder symptoms in children born extremely preterm

PubMed Central

Johnson, Samantha; Kochhar, Puja; Hennessy, Enid; Marlow, Neil; Wolke, Dieter; Hollis, Chris

2016-01-01

Objective To investigate antecedents of Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms in children born extremely preterm (EP; <26 weeks gestation). Method The EPICure Study recruited all babies born EP in the UK and Ireland in March-December 1995. Neurodevelopmental outcomes were assessed at 2.5 (n=283; 90%), 6 (n=160; 78%) and 11 (n=219; 71%) years of age. Parents and teachers completed the Du Paul Rating Scale-IV to assess inattention and hyperactivity/impulsivity symptoms at 11 years. Regression analyses were used to explore the association of neonatal, neurodevelopmental and behavioral outcomes to 6 years with ADHD symptoms at 11 years. Results EP children had significantly more inattention (mean difference 1.2 SD; 95% CI 0.9, 1.5) and hyperactivity/impulsivity (0.5 SD; 0.2, 0.7) than controls, with a significantly greater effect size for inattention than hyperactivity/impulsivity. Significant independent predictors of inattention at 11 years included smaller head circumference, lower IQ and pervasive peer relationship problems at 6 years, and motor development at 2.5 years. In contrast, significant independent predictors of hyperactivity/impulsivity included lower IQ, pervasive conduct problems and ADHD symptoms at 6 years, externalizing problems at 2.5 years and non-white maternal ethnicity. Conclusions EP children are at increased risk for ADHD symptoms, predominantly inattention, for which the antecedents differ by symptom domain. Attention deficits following EP birth were associated with poor brain growth and neurological function. Cognitive and behavioral assessments in early and middle childhood to identify neurodevelopmental and peer relationship problems may be beneficial for identifying EP children at risk for inattention. PMID:27096570

Sustained impact of inattention and hyperactivity-impulsivity on peer problems: mediating roles of prosocial skills and conduct problems in a community sample of children.

PubMed

Andrade, Brendan F; Tannock, Rosemary

2014-06-01

This prospective 2-year longitudinal study tested whether inattentive and hyperactive/impulsive symptom dimensions predicted future peer problems, when accounting for concurrent conduct problems and prosocial skills. A community sample of 492 children (49 % female) who ranged in age from 6 to 10 years (M = 8.6, SD = .93) was recruited. Teacher reports of children's inattention, and hyperactivity/impulsivity symptoms, conduct problems, prosocial skills and peer problems were collected in two consecutive school years. Elevated inattention and hyperactivity/impulsivity in Year-1 predicted greater peer problems in Year-2. Conduct problems in the first and second years of the study were associated with more peer problems, and explained a portion of the relationship between inattention and hyperactivity/impulsivity with peer problems. However, prosocial skills were associated with fewer peer problems in children with elevated inattention and hyperactivity/impulsivity. Inattention and hyperactivity/impulsivity have negative effects on children's peer functioning after 1-year, but concurrent conduct problems and prosocial skills have important and opposing impacts on these associations.

Survey of perceived influence of the conceptual design model of interactive television advertising towards impulse purchase tendency

NASA Astrophysics Data System (ADS)

Sarif, Siti Mahfuzah; Omar, Azizah Che; Shiratuddin, Norshuhada

2016-08-01

With the proliferation of technology assisted shopping, there is growing evidence that impulse buying is an emerging phenomenon, which has been the focus of this study. Literatures indicate that studies related to impulse purchase for interactive television (iTV) advertising are highly scarce. It was found that most of the existing impulse purchase elements are mainly focusing on traditional retail store, website advertising, and traditional TV advertising, but not on iTV advertising. Due to that, through a systematic process, a design model for developing iTV advertising with influence towards impulse purchase tendency was developed and tested in this study. The design model is named as iTVAdIP and comprises of three main components; technology, impulse purchase components, and development process. This paper describes the survey, which measures the influence of iTVAdIP design model towards impulse purchase tendency. 37 potential advertising designers were involved in the survey. The results indicate that the iTVAdIP is practical and workable in developing iTV advertisement that could influence consumer to buy the advertised product.

Direct and indirect effects of impulsivity traits on drinking and driving in young adults.

PubMed

Treloar, Hayley R; Morris, David H; Pedersen, Sarah L; McCarthy, Denis M

2012-09-01

Impulsivity is strongly associated with alcohol-related risk-taking behavior, and this association has been found to be mediated by alcohol cognitions. The current study expanded this literature by comparing the relative association of distinct impulsivity traits with a specific risky behavior--drinking and driving. We then tested whether drinking-and-driving expectancies uniquely mediated this relation over and above other cognitions about alcohol and drinking and driving. College student drivers (n = 816; 53.6% women) completed a paper-and-pencil survey in small groups. Self-report measures assessed alcohol use, impulsivity traits, alcohol expectancies, drinking-and-driving cognitions (i.e., expectancies, attitudes, beliefs), and drinking and driving. Although all impulsivity traits were correlated with drinking and driving, only urgency uniquely contributed to drinking and driving. Indirect effect tests indicated that drinking-and-driving convenience expectancies partially mediated this association as well as that between (lack of) perseverance and drinking and driving. These results remained significant after controlling for alcohol expectancies and other drinking-and-driving cognitions. These findings highlight the importance of distinguishing among impulsivity traits to improve theoretical models of the processes by which personality leads to specific alcohol-related consequences. In addition, results extend previous research by providing evidence for the unique importance of expectancies regarding the convenience of drinking and driving over and above more global alcohol expectancies and other drinking-and-driving cognitions.

Impulsiveness, overactivity, and poorer sustained attention improve by chronic treatment with low doses of l-amphetamine in an animal model of Attention-Deficit/Hyperactivity Disorder (ADHD).

PubMed

Sagvolden, Terje

2011-03-30

ADHD is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Overactivity, impulsiveness, and inattentiveness are presently regarded as the main clinical symptoms. There is no biological marker, but there is considerable evidence to suggest that ADHD behavior is associated with poor dopaminergic and noradrenergic modulation of neuronal circuits that involve the frontal lobes. The best validated animal model of ADHD, the Spontaneously Hypertensive Rat (SHR), shows pronounced overactivity, impulsiveness, and deficient sustained attention. The primary objective of the present research was to investigate behavioral effects of a range of doses of chronic l-amphetamine on ADHD-like symptoms in the SHR. The present study tested the behavioral effects of 0.75 and 2.2 mg l-amphetamine base/kg i.p. in male SHRs and their controls, the Wistar Kyoto rat (WKY). ADHD-like behavior was tested with a visual discrimination task measuring overactivity, impulsiveness and inattentiveness. The striking impulsiveness, overactivity, and poorer sustained attention seen during baseline conditions in the SHR were improved by chronic treatment with l-amphetamine. The dose-response curves were, however, different for the different behaviors. Most significantly, the 0.75 mg/kg dose of l-amphetamine improved sustained attention without reducing overactivity and impulsiveness. The 2.2 mg/kg dose improved sustained attention as well as reduced SHR overactivity and impulsiveness. The effects of l-amphetamine to reduce the behavioral symptoms of ADHD in the SHR were maintained over the 14 days of daily dosing with no evidence of tolerance developing.

Impulsivity interacts with momentary PTSD symptom worsening to predict alcohol use in male veterans.

PubMed

Black, Anne C; Cooney, Ned L; Sartor, Carolyn E; Arias, Albert J; Rosen, Marc I

2018-04-11

Posttraumatic stress disorder (PTSD) is prevalent among veterans who served post-9/11, and co-occurs with problem alcohol and substance use. Studies using ecological momentary assessment have examined the temporal association between time-varying PTSD symptoms and alcohol use. Results suggest individual differences in these associations. We tested hypotheses that alcohol use measured by momentary assessment would be explained by acute increases in PTSD symptoms, and the PTSD-alcohol association would be moderated by trait impulsivity. A sample of 28 male post-9/11-era veterans who reported past-month PTSD symptoms and risky alcohol use were enrolled. On a quasi-random schedule, participants completed three electronic assessments daily for 28 days measuring past 2-h PTSD symptoms, alcohol, and substance use. At baseline, trait impulsivity was measured by the Barratt Impulsiveness Scale. Past-month PTSD symptoms and alcohol use were measured. Using three-level hierarchical models, number of drinks recorded by momentary assessment was modeled as a function of change in PTSD symptoms since last assessment, controlling for lag-1 alcohol and substance use and other covariates. A cross-level interaction tested moderation of the within-time PTSD-alcohol association by impulsivity. A total of 1,522 assessments were completed. A positive within-time association between PTSD symptom change and number of drinks was demonstrated. The association was significantly moderated by impulsivity. Results provide preliminary support for a unique temporal relationship between acute PTSD symptom change and alcohol use among veterans with trait impulsiveness. If replicated in a clinical sample, results may have implications for a targeted momentary intervention.

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Bill Prosser (left) and Eric Madaras, NASA-Langley Research Center, and Jim McGee (right), The Boeing Company, Huntington Beach, Calif., conduct impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

NASA Image and Video Library

2003-10-27

KENNEDY SPACE CENTER, FLA. - In the Orbiter Processing Facility, Bill Prosser (left) and Eric Madaras, NASA-Langley Research Center, and Jim McGee (right), The Boeing Company, Huntington Beach, Calif., conduct impulse tests on the right wing leading edge (WLE) of Space Shuttle Endeavour. The tests monitor how sound impulses propagate through the WLE area. The data collected will be analyzed to explore the possibility of adding new instrumentation to the wing that could automatically detect debris or micrometeroid impacts on the Shuttle while in flight. The study is part of the initiative ongoing at KSC and around the agency to return the orbiter fleet to flight status.

The Utility of Impulsive Bias and Altered Decision Making as Predictors of Drug Efficacy and Target Selection: Rethinking Behavioral Screening for Antidepressant Drugs.

PubMed

Marek, Gerard J; Day, Mark; Hudzik, Thomas J

2016-03-01

Cognitive dysfunction may be a core feature of major depressive disorder, including affective processing bias, abnormal response to negative feedback, changes in decision making, and increased impulsivity. Accordingly, a translational medicine paradigm predicts clinical action of novel antidepressants by examining drug-induced changes in affective processing bias. With some exceptions, these concepts have not been systematically applied to preclinical models to test new chemical entities. The purpose of this review is to examine whether an empirically derived behavioral screen for antidepressant drugs may screen for compounds, at least in part, by modulating an impulsive biasing of responding and altered decision making. The differential-reinforcement-of-low-rate (DRL) 72-second schedule is an operant schedule with a documented fidelity for discriminating antidepressant drugs from nonantidepressant drugs. However, a theoretical basis for this empirical relationship has been lacking. Therefore, this review will discuss whether response bias toward impulsive behavior may be a critical screening characteristic of DRL behavior requiring long inter-response times to obtain rewards. This review will compare and contrast DRL behavior with the five-choice serial reaction time task, a test specifically designed for assessing motoric impulsivity, with respect to psychopharmacological testing and the neural basis of distributed macrocircuits underlying these tasks. This comparison suggests that the existing empirical basis for the DRL 72-second schedule as a pharmacological screen for antidepressant drugs is complemented by a novel hypothesis that altering impulsive response bias for rodents trained on this operant schedule is a previously unrecognized theoretical cornerstone for this screening paradigm. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Dopaminergic Therapy Increases Go Timeouts in the Go/No-Go Task in Patients with Parkinson’s Disease

PubMed Central

Yang, Xue Q.; Lauzon, Brian; Seergobin, Ken N.; MacDonald, Penny A.

2018-01-01

Parkinson’s disease (PD) is characterized by resting tremor, rigidity and bradykinesia. Dopaminergic medications such as L-dopa treat these motor symptoms, but can have complex effects on cognition. Impulse control is an essential cognitive function. Impulsivity is multifaceted in nature. Motor impulsivity involves the inability to withhold pre-potent, automatic, erroneous responses. In contrast, cognitive impulsivity refers to improper risk-reward assessment guiding behavior. Informed by our previous research, we anticipated that dopaminergic therapy would decrease motor impulsivity though it is well known to enhance cognitive impulsivity. We employed the Go/No-go paradigm to assess motor impulsivity in PD. Patients with PD were tested using a Go/No-go task on and off their normal dopaminergic medication. Participants completed cognitive, mood, and physiological measures. PD patients on medication had a significantly higher proportion of Go trial Timeouts (i.e., trials in which Go responses were not completed prior to a deadline of 750 ms) compared to off medication (p = 0.01). No significant ON-OFF differences were found for Go trial or No-go trial response times (RTs), or for number of No-go errors. We interpret that dopaminergic therapy induces a more conservative response set, reflected in Go trial Timeouts in PD patients. In this way, dopaminergic therapy decreased motor impulsivity in PD patients. This is in contrast to the widely recognized effects of dopaminergic therapy on cognitive impulsivity leading in some patients to impulse control disorders. Understanding the nuanced effects of dopaminergic treatment in PD on cognitive functions such as impulse control will clarify therapeutic decisions. PMID:29354045

Different relations between schedule-induced polydipsia and impulsive behaviour in the Spontaneously Hypertensive Rat and in high impulsive Wistar rats: questioning the role of impulsivity in adjunctive behaviour.

PubMed

Ibias, Javier; Pellón, Ricardo

2014-09-01

Rats belonging to three different strains (15 Wistar, 8 Spontaneously Hypertensive - SHR- and 8 Wistar Kyoto - WKY-) were used to evaluate the possible relationship between different levels of impulsivity and development of schedule-induced polydipsia (SIP). We first measured the rats' levels of impulsivity by means of delay-discounting and indifference-point procedures. Secondly, development of SIP was studied under a series of fixed time 15, 30, 60 and 120s food schedules, which were counterbalanced by means of a Latin-square design. Finally, we re-assessed the rats' levels of impulsivity by replicating the delay-discounting test. The findings showed that, starting from equivalent levels of impulsivity, development of SIP differed among the groups of rats. In comparison with the rest of the animals, the SHRs were observed to attain elevated drinking rates under SIP. On the other hand, the Wistar rats which had initial high impulsivity levels similar to those of the SHRs, displayed the lowest rates of induced drinking. Moreover, low levels of impulsivity in Wistar rats prior to SIP acquisition were reflected into high drinking rates. Relation of SIP and impulsivity is questioned by present results, which gives ground to the understanding of the behavioural mechanisms involved in adjunctive behaviour and its usefulness as an animal model of excessive behaviour. Copyright © 2014 Elsevier B.V. All rights reserved.

The direct effects of inattention and hyperactivity/impulsivity on peer problems and mediating roles of prosocial and conduct problem behaviors in a community sample of children.

PubMed

Andrade, Brendan F; Tannock, Rosemary

2013-11-01

This study tested whether children's symptoms of inattention and hyperactivity/impulsivity were associated with peer problems and whether these associations were mediated by conduct problems and prosocial behaviors. A community sample of 500 children, including 245 boys and 255 girls, who ranged in age from 6 to 9 years (M = 7.6, SD = 0.91) were recruited. Teachers' report of children's inattention, hyperactivity/impulsivity, conduct problems, prosocial behaviors, and peer problems was collected. Symptoms of inattention and hyperactivity/impulsivity were significantly positively associated with peer problems. Conduct problems were associated with more peer problems and prosocial behaviors with less peer problems. Conduct problems and prosocial behaviors partially mediated the association between hyperactivity/impulsivity and peer problems and fully mediated the inattention-peer problems association. Findings show that prosocial behaviors and conduct problems are important variables that account for some of the negative impact of symptoms of inattention and hyperactivity/impulsivity on peer functioning.

Impulsivity, self-regulation,and pathological video gaming among youth: testing a mediation model.

PubMed

Liau, Albert K; Neo, Eng Chuan; Gentile, Douglas A; Choo, Hyekyung; Sim, Timothy; Li, Dongdong; Khoo, Angeline

2015-03-01

Given the potential negative mental health consequences of pathological video gaming, understanding its etiology may lead to useful treatment developments. The purpose of the study was to examine the influence of impulsive and regulatory processes on pathological video gaming. Study 1 involved 2154 students from 6 primary and 4 secondary schools in Singapore. Study 2 involved 191 students from 2 secondary schools. The results of study 1 and study 2 supported the hypothesis that self-regulation is a mediator between impulsivity and pathological video gaming. Specifically, higher levels of impulsivity was related to lower levels of self-regulation, which in turn was related to higher levels of pathological video gaming. The use of impulsivity and self-regulation in predicting pathological video gaming supports the dual-system model of incorporating both impulsive and reflective systems in the prediction of self-control outcomes. The study highlights the development of self-regulatory resources as a possible avenue for future prevention and treatment research. © 2011 APJPH.

Multiple spike initiation zones in a neuron implicated in learning in the leech: a computational model.

PubMed

Crisp, Kevin M

2009-03-01

Sensitization of the defensive shortening reflex in the leech has been linked to a segmentally repeated tri-synaptic positive feedback loop. Serotonin from the R-cell enhances S-cell excitability, S-cell impulses cross an electrical synapse into the C-interneuron, and the C-interneuron excites the R-cell via a glutamatergic synapse. The C-interneuron has two unusual characteristics. First, impulses take longer to propagate from the S soma to the C soma than in the reverse direction. Second, impulses recorded from the electrically unexcitable C soma vary in amplitude when extracellular divalent cation concentrations are elevated, with smaller impulses failing to induce synaptic potentials in the R-cell. A compartmental, computational model was developed to test the sufficiency of multiple, independent spike initiation zones in the C-interneuron to explain these observations. The model displays asymmetric delays in impulse propagation across the S-C electrical synapse and graded impulse amplitudes in the C-interneuron in simulated high divalent cation concentrations.

Piezoelectric-based self-powered electronic adjustable impulse switches

NASA Astrophysics Data System (ADS)

Rastegar, Jahangir; Kwok, Philip

2018-03-01

Novel piezoelectric-based self-powered impulse detecting switches are presented. The switches are designed to detect shock loading events resulting in acceleration or deceleration above prescribed levels and durations. The prescribed acceleration level and duration thresholds are adjustable. They are provided with false trigger protection logic. The impulse switches are provided with electronic and logic circuitry to detect prescribed impulse events and reject events such as high amplitude but short duration shocks, and transportation vibration and similar low amplitude and relatively long duration events. They can be mounted directly onto electronics circuit boards, thereby significantly simplifying the electrical and electronic circuitry, simplifying the assembly process and total cost, significantly reducing the occupied volume, and in some applications eliminating the need for physical wiring to and from the impulse switches. The design of prototypes and testing under realistic conditions are presented.

Vortex systems on slender rotating bodies and their effect on the aerodynamic coefficients

NASA Technical Reports Server (NTRS)

Fiechter, M.

1986-01-01

The turbulent flow of rotational bodies up to a length of 20 diameters with various head shapes and cylindrical tails was examined in the subsonic wind tunnel with the Mach number of M = 0.1. At angles of incidence lower than 30 degrees, a pair of symmetrical eddies rests stationary from head to tail on the trailing side, very close to the body. At angles between 30 and 60 degrees, the stationary eddies are asymmetrically pushed off. Between 60 and 90 degrees, the eddies detach themselves in an instationary manner. This includes, for example, the turbulent flow at the start-up of flying bodies in the presence of lateral winds. The results of measurments obtained by Mello at M = 2, an impulse method, and the cross flow theory according to Allen are used for comparison.

Suppression of ITI by array head reading and 2D-equalization

NASA Astrophysics Data System (ADS)

Nakamura, Y.; Suzuto, R.; Osawa, H.; Okamoto, Y.; Kanai, Y.; Muraoka, H.

2017-05-01

Two-dimensional magnetic recording (TDMR) by shingled magnetic recording (SMR) draws attention as a next generation technology to increase the recording density in hard disk drive (HDD). It is shown that the two-dimensional finite impulse response (2D-FIR) filter provides gain the reproducing waveforms from an array head with 3 readers in the TDMR under a specification of 4 Tbit/inch.2 We evaluate the effect of the intertrack interference (ITI) reduction by 2D-FIR using the correlation between the real FIR filter output and the partial response class-I (PR1) signal corresponding to recording sequence by the computer simulation. The results show that the 2D-FIR filter is effective to mitigate ITI and improves the signal-to-noise ratio at the discriminate point by about 0.6 dB.

Acoustic radiation force impulse shear wave elastography (ARFI) of acute and chronic pancreatitis and pancreatic tumor.

PubMed

Goertz, Ruediger S; Schuderer, Johanna; Strobel, Deike; Pfeifer, Lukas; Neurath, Markus F; Wildner, Dane

2016-12-01

Acoustic Radiation Force Impulse (ARFI) elastography evaluates tissue stiffness non-invasively and has rarely been applied to pancreas examinations so far. In a prospective and retrospective analysis, ARFI shear wave velocities of healthy parenchyma, pancreatic lipomatosis, acute and chronic pancreatitis, adenocarcinoma and neuroendocrine tumor (NET) of the pancreas were evaluated and compared. In 95 patients ARFI elastography of the pancreatic head, and also of the tail for a specific group, was analysed retrospectively. Additionally, prospectively in 100 patients ARFI was performed in the head and tail of the pancreas. A total of 195 patients were included in the study. Healthy parenchyma (n=21) and lipomatosis (n=30) showed similar shear wave velocities of about 1.3m/s. Acute pancreatitis (n=35), chronic pancreatitis (n=53) and adenocarcinoma (n=52) showed consecutively increasing ARFI values, respectively. NET (n=4) revealed the highest shear wave velocities amounting to 3.62m/s. ARFI elastography showed relevant differences between acute pancreatitis and chronic pancreatitis or adenocarcinoma. With a cut-off value of 1.74m/s for the diagnosis of a malignant disease the sensitivity was 91.1% whereas the specificity amounted to 60.4%. ARFI shear wave velocities present differences in various pathologies of the pancreas. Acute and chronic pancreatitis as well as neoplastic lesions show high ARFI values. Very high elasticity values may indicate malignant disease of the pancreas. However, there is a considerable overlap between the entities. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Reward Sensitivity and Waiting Impulsivity: Shift towards Reward Valuation away from Action Control

PubMed Central

Mechelmans, Daisy J; Strelchuk, Daniela; Doñamayor, Nuria; Banca, Paula; Robbins, Trevor W; Baek, Kwangyeol

2017-01-01

Abstract Background Impulsivity and reward expectancy are commonly interrelated. Waiting impulsivity, measured using the rodent 5-Choice Serial Reaction Time task, predicts compulsive cocaine seeking and sign (or cue) tracking. Here, we assess human waiting impulsivity using a novel translational task, the 4-Choice Serial Reaction Time task, and the relationship with reward cues. Methods Healthy volunteers (n=29) performed the monetary incentive delay task as a functional MRI study where subjects observe a cue predicting reward (cue) and wait to respond for high (£5), low (£1), or no reward. Waiting impulsivity was tested with the 4-Choice Serial Reaction Time task. Results For high reward prospects (£5, no reward), greater waiting impulsivity on the 4-CSRT correlated with greater medial orbitofrontal cortex and lower supplementary motor area activity to cues. In response to high reward cues, greater waiting impulsivity was associated with greater subthalamic nucleus connectivity with orbitofrontal cortex and greater subgenual cingulate connectivity with anterior insula, but decreased connectivity with regions implicated in action selection and preparation. Conclusion These findings highlight a shift towards regions implicated in reward valuation and a shift towards compulsivity away from higher level motor preparation and action selection and response. We highlight the role of reward sensitivity and impulsivity, mechanisms potentially linking human waiting impulsivity with incentive approach and compulsivity, theories highly relevant to disorders of addiction. PMID:29020291

Dielectric breakdown strength of magnetic nanofluid based on insulation oil after impulse test

NASA Astrophysics Data System (ADS)

Nazari, M.; Rasoulifard, M. H.; Hosseini, H.

2016-02-01

In this study, the dielectric breakdown strength of magnetic nanofluids based on transformer mineral oil for use in power systems is reviewed. Nano oil samples are obtained from dispersion of the magnetic nanofluid within uninhibited transformer mineral oil NYTRO LIBRA as the base fluid. AC dielectric breakdown voltage measurement was carried out according to IEC 60156 standard and the lightning impulse breakdown voltage was obtained by using the sphere-sphere electrodes in an experimental setup for nano oil in volume concentration of 0.1-0.6%. Results indicate improved AC and lightning impulse breakdown voltage of nano oil compared to the base oil. AC test was performed again after applying impulse current and result showed that nano oil unlike the base oil retains its dielectric properties. Increase the dielectric strength of the nano oil is mainly due to dielectric and magnetic properties of Fe3O4 nanoparticles that act as free electrons snapper, and reduce the rate of free electrons in the ionization process.

Unraveling the nature of hyperactivity in children with attention-deficit/hyperactivity disorder.

PubMed

Ohashi, Kyoko; Vitaliano, Gordana; Polcari, Ann; Teicher, Martin H

2010-04-01

Seated hyperactivity is a defining feature of the combined and predominantly hyperactive-impulsive subtypes of attention-deficit/hyperactivity disorder (ADHD), but its underlying nature is unknown. To determine whether hyperactivity is a consequence of an impaired ability to inhibit activity to low levels or to maintain positional stability. Case-control study. Academic research center and school. Sixty-two boys 9 to 12 years of age (of 73 screened), recruited from the community by advertisement, who met DSM-IV criteria for ADHD combined subtype on structured interview. Sixty-two controls were selected by matching for age and sex from a community sample of 1168 subjects in 3 participating school districts. Pupils with Conners' Teacher Rating Scores Revised within +/-1 SD of the mean for age were eligible for randomized matching. Intervention Infrared motion analysis of head-marker movements (50 Hz) during performance of a 15-minute cognitive control task. Subjects with ADHD were tested at least 18 hours following their last dose of methylphenidate and again 120 minutes after a 0.4-mg/kg probe dose. Inhibitory control (spike and basal amplitude) and head-marker stability (approximate entropy, Lyapunov, and spectral exponents). Inhibitory control measures were 2-fold higher in subjects with ADHD (d' = 0.63-0.95). Group differences in head-marker stability were even greater (d' = 2.20-4.71; receiver operating characteristic area = 0.956-1.0). Methylphenidate restored inhibitory ability to control levels but only partially corrected stability deficits, which still distinguished subjects with ADHD from controls (receiver operating characteristic area = 0.722-0.995). Children with ADHD have a deficient ability to inhibit activity to low levels and unstable control of head-marker position characterized by deterministic chaos (sensitivity to initial conditions). These deficits differed in degree of correctability by methylphenidate, suggesting that they may be mediated by different neural circuits (eg, corticostriatal vs cerebrovestibular).

Determination of Acoustic Effects on Marine Mammals and Sea Turtles for the Northwest Training and Testing Environmental Impact Statement/Overseas Environmental Impact Statement

DTIC Science & Technology

2015-11-01

world events. An unclassified version of the sources modeled within each source class category is provided in the appendix. 4.3 IMPULSIVE...water column. The process outlined in this section is applicable to both impulsive and non-impulsive sources, with the exception of the overpopulation ...1. An overpopulation factor is determined for the animals within both an inner box associated with the track boundary for the activity and an outer

Voyager Uranus encounter 0.2lbf T/VA short pulse test report

NASA Technical Reports Server (NTRS)

1986-01-01

The attitude control thrusters on the Voyager spacecraft were tested for operation at electrical pulse widths of less than the current 10-millisecond minimum to reduce impulse bit and, therefore, reduce image smear of pictures taken during the Uranus encounter. Thrusters with the identical configuration of the units on the spacecraft were fired in an altitude chamber to characterize impulse bit and impulse bit variations as a function of electrical pulse widths and to determine if the short pulses decreased thruster life. Pulse widths of 4.0 milliseconds provide approximately 45 percent of the impulse provided by a 10-ms pulse, and thruster-to-thruster and pulse-to-pulse variation is approximately plus or minus 10 percent. Pulse widths shorter than 4 ms showed wide variation, and no pulse was obtained at 3 ms. Three thrusters were each subjected to 75,000 short pulses of 4 ms or less without performance degradation. A fourth thruster exhibited partial flow blockage after 13,000 short pulses, but this was attributed to prevous test history and not short pulse exposure. The Voyager attitude control thrusters should be considered flight qualified for short pulse operation at pulse widths of 4.0 ms or more.

Influence of history of head trauma and epilepsy on delinquents in a juvenile classification home.

PubMed

Miura, Hideki; Fujiki, Masumi; Shibata, Arihiro; Ishikawa, Kenji

2005-12-01

Juvenile delinquents often show poor impulse control and cognitive abnormalities, which may be related to disturbances in brain development due to head trauma and/or epilepsy. The aim of the present study was to examine the influence of head trauma and/or epilepsy on delinquent behavior. We examined 1,336 juvenile delinquents (1,151 males and 185 females) who had been admitted to the Nagoya Juvenile Classification Home, Aichi, Japan. Among them, 52 subjects with a history of epilepsy, convulsion or loss of consciousness, head injury requiring neurological assessment and/or treatment, or neurosurgical operation (head trauma/epilepsy group), were examined by electroencephalography and compared to subjects without these histories (control group) with respect to types of crime, history of amphetamine use, psychiatric treatment, child abuse, and family history. Among the 52 subjects, 43 (82.7%) showed abnormal findings. The head trauma/epilepsy group had significantly higher rates of psychiatric treatment (P<0.0001, OR=16.852, 95% CI=8.068-35.199) and family history of drug abuse (P<0.05, OR=2.303, 95% CI=1.003-5.290). Furthermore, the percentage of members who were sent to juvenile training school by the family court was significantly higher in the head trauma/epilepsy group (72.5%) than in the control group (38.9%, P<0.0001). The juvenile delinquents who had a history of head trauma and/or epilepsy showed a high prevalence of electroencephalograph abnormality, and higher rates of psychiatric treatment and family history of drug abuse, and were more likely to be sent to juvenile training school by the family court.

Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

NASA Technical Reports Server (NTRS)

Henderson, R. A.; Schrag, R. L.

1986-01-01

A summary of modeling the electrical system aspects of a coil and metal target configuration resembling a practical electro-impulse deicing (EIDI) installation, and a simple circuit for providing energy to the coil, was presented. The model was developed in sufficient theoretical detail to allow the generation of computer algorithms for the current in the coil, the magnetic induction on both surfaces of the target, the force between the coil and target, and the impulse delivered to the target. These algorithms were applied to a specific prototype EIDI test system for which the current, magnetic fields near the target surfaces, and impulse were previously measured.

Effect of ITE and nozzle exit cone erosion on specific impulse of solid rocket motors

NASA Astrophysics Data System (ADS)

Smith-Kent, Randall; Ridder, Jeffrey P.; Loh, Hai-Tien; Abel, Ralph

1993-06-01

Specific impulse loss due to the use of a slowly eroding integral throat entrance, or a throat insert, with a faster eroding nozzle exit cone is studied. It is suggested that an oblique shock wave produced by step-off erosion results in loss of specific impulse. This is studied by use of a shock capturing CFD method. The shock loss predictions for first-stage Peacekeeper and Castor 25 motors are found to match the trends of the test data. This work suggests that a loss mechanism, previously unaccounted, should be considered in the specific impulse prediction procedure for nozzles with step-off exit cone erosion.

The Relationship between Impulsivity and Internet Gaming Disorder in Young Adults: Mediating Effects of Interpersonal Relationships and Depression.

PubMed

Ryu, Hyera; Lee, Ji-Yoon; Choi, Aruem; Park, Sunyoung; Kim, Dai-Jin; Choi, Jung-Seok

2018-03-06

Background: This study aimed to explore relationships between impulsivity, interpersonal relationships, depression, and Internet Gaming Disorder (IGD) symptoms. Methods: A total of 118 young adults participated in this study: 67 IGD patients who met five or more of the DSM-5 diagnostic criteria for IGD and 56 healthy controls. We administered questionnaires to assess IGD symptoms (Young's Internet Addiction Test; Y-IAT), impulsivity (Barratt Impulsiveness Scale; BIS-11), interpersonal relationship (Relationship Change Scale; RCS), and depression (Beck Depression Inventory; BDI). We used PROCESS macro in SPSS to perform mediation analysis. Results: IGD symptom was positively related to depression and impulsivity, and negatively related to the quality of interpersonal relationships. Mediation analysis revealed full mediation effects of interpersonal relationships and depression on the association between impulsivity and IGD symptoms in the IGD group. Specifically, even after adjusting for gender as a covariate, high impulsivity was associated with greater difficulty with interpersonal relationships; which further affected depression and increased the risk of IGD. Conclusions: These results demonstrate the importance of early intervention in IGD patients, particularly in young adults with high impulsivity. When intervening in adults' IGD, we should consider not only individual factors (e.g., depression) but also socioenvironmental factors (e.g., interpersonal relationships).

Executive functions, impulsivity, and inhibitory control in adolescents: A structural equation model

PubMed Central

Fino, Emanuele; Melogno, Sergio; Iliceto, Paolo; D’Aliesio, Sara; Pinto, Maria Antonietta; Candilera, Gabriella; Sabatello, Ugo

2014-01-01

Background. Adolescence represents a critical period for brain development, addressed by neurodevelopmental models to frontal, subcortical-limbic, and striatal activation, a pattern associated with rise of impulsivity and deficits in inhibitory control. The present study aimed at studying the association between self-report measures of impulsivity and inhibitory control with executive function in adolescents, employing structural equation modeling. Method. Tests were administered to 434 high school students. Acting without thinking was measured through the Barratt Impulsiveness Scale and the Dickman Impulsivity Inventory, reward sensitivity through the Behavioral Activation System, and sensation seeking through the Zuckerman–Kuhlman–Aluja Personali- ty Questionnaire. Inhibitory control was assessed through the Behavioral Inhibition System. The performance at the Wisconsin Card Sorting Task indicated executive function. Three models were specified using Sample Covariance Matrix, and the estimated parameters using Maximum Likelihood. Results. In the final model, impulsivity and inhibitory control predicted executive function, but sensation seeking did not. The fit of the model to data was excellent. Conclusions. The hypothesis that inhibitory control and impulsivity are predictors of executive function was supported. Our results appear informative of the validity of self-report measures to examine the relation between impulsivity traits rather than others to regulatory function of cognition and behavior. PMID:25157298

Cognitive control training for emotion-related impulsivity.

PubMed

Peckham, Andrew D; Johnson, Sheri L

2018-06-01

Many forms of psychopathology are tied to a heightened tendency to respond impulsively to strong emotions, and this tendency, in turn, is closely tied to problems with cognitive control. The goal of the present study was to test whether a two-week, six-session cognitive control training program is efficacious in reducing emotion-related impulsivity. Participants (N = 52) reporting elevated scores on an emotion-related impulsivity measure completed cognitive control training targeting working memory and response inhibition. A subset of participants were randomized to a waitlist control group. Impulsivity, emotion regulation, and performance on near and far-transfer cognitive tasks were assessed at baseline and after completion of training. Emotion-related impulsivity declined significantly from pre-training to post-training and at two-week follow-up; improvements were not observed in the waitlist control group. A decrease in brooding rumination and an increase in reappraisal were also observed. Participants showed significant improvements on trained versions of the working memory and inhibition tasks as well as improvements on an inhibition transfer task. In sum, these preliminary findings show that cognitive training appears to be well-tolerated for people with significant emotion-driven impulsivity. Results provide preliminary support for the efficacy of cognitive training interventions as a way to reduce emotion-related impulsivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Relationship between Impulsivity and Internet Gaming Disorder in Young Adults: Mediating Effects of Interpersonal Relationships and Depression

PubMed Central

Ryu, Hyera; Lee, Ji-Yoon; Choi, Aruem; Park, Sunyoung; Kim, Dai-Jin

2018-01-01

Background: This study aimed to explore relationships between impulsivity, interpersonal relationships, depression, and Internet Gaming Disorder (IGD) symptoms. Methods: A total of 118 young adults participated in this study: 67 IGD patients who met five or more of the DSM-5 diagnostic criteria for IGD and 56 healthy controls. We administered questionnaires to assess IGD symptoms (Young’s Internet Addiction Test; Y-IAT), impulsivity (Barratt Impulsiveness Scale; BIS-11), interpersonal relationship (Relationship Change Scale; RCS), and depression (Beck Depression Inventory; BDI). We used PROCESS macro in SPSS to perform mediation analysis. Results: IGD symptom was positively related to depression and impulsivity, and negatively related to the quality of interpersonal relationships. Mediation analysis revealed full mediation effects of interpersonal relationships and depression on the association between impulsivity and IGD symptoms in the IGD group. Specifically, even after adjusting for gender as a covariate, high impulsivity was associated with greater difficulty with interpersonal relationships; which further affected depression and increased the risk of IGD. Conclusions: These results demonstrate the importance of early intervention in IGD patients, particularly in young adults with high impulsivity. When intervening in adults’ IGD, we should consider not only individual factors (e.g., depression) but also socioenvironmental factors (e.g., interpersonal relationships). PMID:29509708

Dimensions of impulsivity in relation to eating disorder recovery.

PubMed

Bardone-Cone, Anna M; Butler, Rachel M; Balk, Margaret R; Koller, Katherine A

2016-11-01

Impulsivity is associated with eating pathology, but different dimensions of impulsivity have not been extensively studied in the eating disorders. The current study examined the relationship between four facets of impulsivity and eating disorder recovery status. Females formerly seen for an eating disorder were categorized as having an eating disorder (n = 53), partially recovered (n = 15), or fully recovered (n = 20) based on a diagnostic interview and physical, behavioral, and psychological indices. These groups and non-eating disorder controls were compared on impulsivity facets from the UPPS Impulsive Behavior Scale (UPPS): Urgency (negative urgency), Premeditation (lack of), Perseverance (lack of), and Sensation Seeking. Negative urgency (the tendency to engage in impulsive behavior to alleviate negative affect) was related to recovery. The fully recovered group and controls experienced significantly less negative urgency than those with a current eating disorder; the partially recovered group did not differ from the eating disorder group. Findings suggest that negative urgency may be a particularly important facet of impulsivity to target in therapeutic intervention for eating disorders, especially among those with a history of binge eating and/or purging. Future longitudinal work is needed to test a potential causal relationship between negative urgency and eating disorder recovery. © 2016 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:1027-1031). © 2016 Wiley Periodicals, Inc.

A torsion balance for impulse and thrust measurements of micro-Newton thrusters

NASA Astrophysics Data System (ADS)

Yang, Yuan-Xia; Tu, Liang-Cheng; Yang, Shan-Qing; Luo, Jun

2012-01-01

This paper reports the performance of a torsion-type thrust stand suitable for studies of micro-Newton thrusters, which is developed for ground testing the micro-Newton thruster in Chinese Test of the Equivalence Principle with Optical readout space mission. By virtue of specially suspending design and precise assembly of torsion balance configuration, the thrust stand with load capacity up to several kilograms is able to measure the impulse bit up to 1350 μNs with a resolution of 0.47 μNs, and the average thrust up to 264 μN with a resolution of 0.09 μN in both open and close loop operation. A pulsed plasma thruster, the preliminary prototype developed for Chinese TEPO space mission, is tested by the thrust stand, and the results reveal that the average impulse bit per pulse is measured to be 58.4 μNs with a repeatability of about 5%.

Audiovestibular impairments associated with intracranial hypotension.

PubMed

Choi, Jae-Hwan; Cho, Kee-Yong; Cha, Seung-Yi; Seo, Jae-Deuk; Kim, Min-Ji; Choi, Yu Ri; Kim, Sung-Hee; Kim, Ji-Soo; Choi, Kwang-Dong

2015-10-15

To investigate the patterns and mechanisms of audiovestibular impairments associated with intracranial hypotension. We had consecutively recruited 16 patients with intracranial hypotension at the Neurology Center of Pusan National University Hospital for two years. Spontaneous, gaze-evoked, and positional nystagmus were recorded using 3D video-oculography in all patients, and the majority of them also had pure tone audiometry and bithermal caloric tests. Of the 16 patients, five (31.3%) reported neuro-otological symptoms along with the orthostatic headache while laboratory evaluation demonstrated audiovestibular impairments in ten (62.5%). Oculographic analyses documented spontaneous and/or positional nystagmus in six patients (37.5%) including weak spontaneous vertical nystagmus with positional modulation (n=4) and pure positional nystagmus (n=2). One patient presented with recurrent spontaneous vertigo and tinnitus mimicking Meniere's disease, and showed unidirectional horizontal and torsional nystagmus with normal head impulse tests during the attacks. Bithermal caloric tests were normal in all nine patients tested. Audiometry showed unilateral (n=6) or bilateral (n=1) sensorineural hearing loss in seven (53.8%) of the 13 patients tested. Intracranial hypotension frequently induces audiovestibular impairments. In addition to endolymphatic hydrops and irritation of the vestibulocochlear nerve, compression or traction of the brainstem or cerebellum due to loss of CSF buoyancy may be considered as a mechanism of frequent spontaneous or positional vertical nystagmus in patients with intracranial hypotension. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of Accelerometer Data from a Woven Inflatable Creep Burst Test

NASA Technical Reports Server (NTRS)

James, George H.; Grygier, Michael; Selig, Molly M.

2015-01-01

Accelerometers were used to montor an inflatable test article during a creep test to failure. The test article experienced impulse events that were classified based on the response of the sensors and their time-dependent manifestation. These impulse events required specialized techniques to process the structural dynamics data. However, certain phenomena were defined as worthy of additional study. An assessment of one phenomena (a frequency near 1000Hz) showed a time dependent frequency and an amplitude that increased significantly near the end of the test. Hence, these observations are expected to drive future understanding of and utility in inflatable space structures.

VOR Gain Is Related to Compensatory Saccades in Healthy Older Adults

PubMed Central

Anson, Eric R.; Bigelow, Robin T.; Carey, John P.; Xue, Qian-Li; Studenski, Stephanie; Schubert, Michael C.; Agrawal, Yuri

2016-01-01

Objective: Vestibulo-ocular reflex (VOR) gain is well-suited for identifying rotational vestibular dysfunction, but may miss partial progressive decline in age-related vestibular function. Since compensatory saccades might provide an alternative method for identifying subtle vestibular decline, we describe the relationship between VOR gain and compensatory saccades in healthy older adults. Methods: Horizontal VOR gain was measured in 243 subjects age 60 and older from the Baltimore Longitudinal Study of Aging using video head impulse testing (HIT). Saccades in each HIT were identified as either “compensatory” or “compensatory back-up,” i.e., same or opposite direction as the VOR response respectively. Saccades were also classified as “covert” (occurring during head movement) and “overt” (occurring after head movement). The relationship between VOR gain and percentage of HITs with saccades, as well as the relationship between VOR gain and saccade latency and amplitude, were evaluated using regression analyses adjusting for age, gender, and race. Results: In adjusted analyses, the percentage of HITs with compensatory saccades increased 4.5% for every 0.1 decrease in VOR gain (p < 0.0001). Overt compensatory saccade amplitude decreased 0.6° (p < 0.005) and latency increased 90 ms (p < 0.001) for every 0.1 increase in VOR gain. Covert back-up compensatory saccade amplitude increased 0.4° for every 0.1 increase in VOR gain. Conclusion: We observed significant relationships between VOR gain and compensatory saccades in healthy older adults. Lower VOR gain was associated with larger amplitude, shorter latency compensatory saccades. Compensatory saccades reflect underlying rotational vestibular hypofunction, and may be particularly useful at identifying partial vestibular deficits as occur in aging adults. PMID:27445793

A skin friction gauge for impulsive flows

NASA Technical Reports Server (NTRS)

Goyne, C. P.; Paull, A.; Stalker, R. J.

1995-01-01

A new skin friction gauge has been designed for use in impulsive facilities. The gauge was tested in the T4 free piston shock tunnel, at the University of Queensland, using a 1.5 m long plate that formed one of the inner walls of a rectangular duct. The test gas was fair and the test section free stream flow had a stagnation enthalpy of 4.7 MJ/kg. Measurements were conducted in a laminar and turbulent boundary layer. The measurements compared well with laminar and turbulent analytical theory.

Meteoroid Fragmentation as Revealed in Head- and Trail-Echoes Observed with the Arecibo UHF and VHF Radars

NASA Technical Reports Server (NTRS)

Mathews, J. D.; Malhorta, A.

2011-01-01

We report recent 46.8/430 MHz (VHF/UHF) radar meteor observations at Arecibo Observatory (AO) that reveal many previously unreported features in the radar meteor return - including flare-trails at both UHF and VHF - that are consistent with meteoroid fragmentation. Signature features of fragmentation include strong intra-pulse and pulse-to-pulse fading as the result of interference between or among multiple meteor head-echo returns and between head-echo and impulsive flare or "point" trail-echoes. That strong interference fading occurs implies that these scatterers exhibit well defined phase centers and are thus small compared with the wavelength. These results are consistent with and offer advances beyond a long history of optical and radar meteoroid fragmentation studies. Further, at AO, fragmenting and flare events are found to be a large fraction of the total events even though these meteoroids are likely the smallest observed by the major radars. Fragmentation is found to be a major though not dominate component of the meteors observed at other HPLA radars that are sensitive to larger meteoroids.

Modulation of central serotonin affects emotional information processing in impulsive aggressive personality disorder.

PubMed

Lee, Royce J; Gill, Andrew; Chen, Bing; McCloskey, Michael; Coccaro, Emil F

2012-06-01

The mechanistic model whereby serotonin affects impulsive aggression is not completely understood. The purpose of this study was to test the hypothesis that depletion of serotonin reserves by tryptophan depletion affects emotional information processing in susceptible individuals. The effect of tryptophan (vs placebo) depletion on processing of Ekman emotional faces was compared in impulsive aggressive personality disordered, male and female adults with normal controls. All subjects were free of psychotropic medications, medically healthy, nondepressed, and substance free. Additionally, subjective mood state and vital signs were monitored. For emotion recognition, a significant interaction of Aggression × Drug × Sex (F(1, 31) = 7.687, P = 0.009) was found, with male normal controls but not impulsive aggressive males showing increased recognition of fear. For intensity ratings of emotional faces, a significant interaction was discovered of Drug × Group × Sex (F(1, 31) = 5.924, P = 0.021), with follow-up tests revealing that males with intermittent explosive disorder tended to increase intensity ratings of angry faces after tryptophan depletion. Additionally, tryptophan depletion was associated with increased heart rate in all subjects, and increased intensity of the subjective emotional state of "anger" in impulsive aggressive subjects. Individuals with clinically relevant levels of impulsive aggression may be susceptible to effects of serotonergic depletion on emotional information processing, showing a tendency to exaggerate their impression of the intensity of angry expressions and to report an angry mood state after tryptophan depletion. This may reflect heightened sensitivity to the effects of serotonergic dysregulation, and suggests that what underlies impulsive aggression is either supersensitivity to serotonergic disturbances or susceptibility to fluctuations in central serotonergic availability.

Effect of knee and trunk angle on kinetic variables during the isometric midthigh pull: test-retest reliability.

PubMed

Comfort, Paul; Jones, Paul A; McMahon, John J; Newton, Robert

2015-01-01

The isometric midthigh pull (IMTP) has been used to monitor changes in force, maximum rate of force development (mRFD), and impulse, with performance in this task being associated with performance in athletic tasks. Numerous postures have been adopted in the literature, which may affect the kinetic variables during the task; therefore, the aim of this investigation was to determine whether different knee-joint angles (120°, 130°, 140°, and 150°) and hip-joint angles (125° and 145°), including the subjects preferred posture, affect force, mRFD, and impulse during the IMTP. Intraclass correlation coefficients demonstrated high within-session reliability (r ≥ .870, P < .001) for all kinetic variables determined in all postures, excluding impulse measures during the 130° knee-flexion, 125° hip-flexion posture, which showed a low to moderate reliability (r = .666-.739, P < .001), while between-sessions testing demonstrated high reliability (r > .819, P < .001) for all kinetic variables. There were no significant differences in peak force (P > .05, Cohen d = 0.037, power = .408), mRFD (P > .05, Cohen d = 0.037, power = .409), or impulse at 100 ms (P > .05, Cohen d = 0.056, power = .609), 200 ms (P > .05, Cohen d = 0.057, power = .624), or 300 ms (P > .05, Cohen d = 0.061, power = .656) across postures. Smallest detectable differences demonstrated that changes in performance of >1.3% in peak isometric force, >10.3% in mRFD, >5.3% in impulse at 100 ms, >4.4% in impulse at 200 ms, and >7.1% in impulse at 300 ms should be considered meaningful, irrespective of posture.

Impaired Decision-Making, Higher Impulsivity, and Drug Severity in Substance Dependence and Pathological Gambling.

PubMed

Krmpotich, Theodore; Mikulich-Gilbertson, Susan; Sakai, Joseph; Thompson, Laetitia; Banich, Marie T; Tanabe, Jody

2015-01-01

Substance use disorder is characterized by impaired decision making, impulsivity, and risk taking. Pathological gambling shares many of these characteristics, and having both diagnoses may be associated with greater problems than either diagnosis alone. We investigated whether among substance-dependent individuals, comorbid pathological gambling would be associated with worse decision making, greater impulsivity, risk taking, and drug severity. Ninety-six substance-dependent individuals were recruited from a residential treatment program and divided into 1 of the 2 groups depending on whether they met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for pathological gambling (SDPG, n = 26) or not (SD, n = 70). Ninety-two controls were recruited from the community. Participants completed a decision-making task (modified Iowa Gambling Task), measures of impulsivity (Barratt Impulsivity Scale and Delay Discounting), and risk taking (Balloon Analog Risk Task). Decision making was analyzed using a computational model. We tested for group differences using analysis of covariance or Kruskal-Wallis and appropriate post-hoc tests. The groups differed in decision-making parameters (P < 0.001) and self-reported impulsivity (P < 0.001). All post-hoc comparisons were significant on these measures, and indicated stepwise changes in controls, followed by SD, followed by SDPG, with SDPG performing worse on decision making and being more impulsive. Compared with SD, SDPG had greater drug severity (P < 0.001). No group differences were observed in delay discounting or risk taking. Compared with individuals with substance dependence without pathological gambling, those with both disorders demonstrated worse decision making and significantly more drug-related symptoms. When evaluating patients with substance dependence, clinicians should consider diagnostic assessments for gambling, as the co-occurrence of both disorders may impact clinical characteristics.

Evidence for shared genetic risk between ADHD symptoms and reduced mathematics ability: a twin study

PubMed Central

Greven, Corina U.; Kovas, Yulia; Willcutt, Erik G.; Petrill, Stephen A.; Plomin, Robert

2013-01-01

Background Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Methods Data came from more than 6,000 12-year-old twin pairs from the U.K. population-representative Twins Early Development Study. Parents rated each twin’s behaviour using a DSM-IV-based 18-item questionnaire of inattentive and hyperactive-impulsive ADHD symptoms. Mathematics tests based on the U.K. National Curriculum were completed by each twin. The twins also completed standardised tests of reading and general cognitive ability. Multivariate twin model fitting was applied. Results Inattentive and hyperactive-impulsive ADHD symptoms were highly heritable (67% and 73%, respectively). Mathematics ability was moderately heritable (46%). Mathematics ability and inattentiveness showed a significantly greater phenotypic correlation (rp=−0.26) and genetic correlation (rA=−0.41) than mathematics ability and hyperactivity-impulsivity (rp=−0.18; rA=−0.22). The genetic correlation between inattentiveness and mathematics ability was largely independent from hyperactivity-impulsivity, and was only partially accounted for by genetic influences related to reading and general cognitive ability. Conclusions Results revealed the novel finding that mathematics ability shows significantly stronger phenotypic and genetic associations with inattentiveness than with hyperactivity-impulsivity. Genetic associations between inattentiveness and mathematics ability could only partially be accounted for by hyperactivity-impulsivity, reading and general cognitive ability. Results suggest that mathematics ability is associated with ADHD symptoms largely because it shares genetic risk factors with inattentiveness, and provide further evidence for considering inattentiveness and hyperactivity-impulsivity separately. DNA markers for ADHD symptoms (especially inattentiveness) may also be candidate risk factors for mathematics ability and vice versa. PMID:23731013

Evidence for shared genetic risk between ADHD symptoms and reduced mathematics ability: a twin study.

PubMed

Greven, Corina U; Kovas, Yulia; Willcutt, Erik G; Petrill, Stephen A; Plomin, Robert

2014-01-01

Attention-deficit/hyperactivity disorder (ADHD) symptoms and mathematics ability are associated, but little is known about the genetic and environmental influences underlying this association. Data came from more than 6,000 twelve-year-old twin pairs from the UK population-representative Twins Early Development Study. Parents rated each twin's behaviour using a DSM-IV-based 18-item questionnaire of inattentive and hyperactive-impulsive ADHD symptoms. Mathematics tests based on the UK National Curriculum were completed by each twin. The twins also completed standardised tests of reading and general cognitive ability. Multivariate twin model fitting was applied. Inattentive and hyperactive-impulsive ADHD symptoms were highly heritable (67% and 73% respectively). Mathematics ability was moderately heritable (46%). Mathematics ability and inattentiveness showed a significantly greater phenotypic correlation (r(p) = -.26) and genetic correlation (r(A) = -.41) than mathematics ability and hyperactivity-impulsivity (r(p) = -.18; r(A) = -.22). The genetic correlation between inattentiveness and mathematics ability was largely independent from hyperactivity-impulsivity, and was only partially accounted for by genetic influences related to reading and general cognitive ability. Results revealed the novel finding that mathematics ability shows significantly stronger phenotypic and genetic associations with inattentiveness than with hyperactivity-impulsivity. Genetic associations between inattentiveness and mathematics ability could only partially be accounted for by hyperactivity-impulsivity, reading and general cognitive ability. Results suggest that mathematics ability is associated with ADHD symptoms largely because it shares genetic risk factors with inattentiveness, and provide further evidence for considering inattentiveness and hyperactivity-impulsivity separately. DNA markers for ADHD symptoms (especially inattentiveness) may also be candidate risk factors for mathematics ability and vice versa. © 2013 The Authors. Journal of Child Psychology and Psychiatry © 2013 Association for Child and Adolescent Mental Health.

Impulsiveness, overactivity, and poorer sustained attention improve by chronic treatment with low doses of l-amphetamine in an animal model of Attention-Deficit/Hyperactivity Disorder (ADHD)

PubMed Central

2011-01-01

Background ADHD is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Overactivity, impulsiveness, and inattentiveness are presently regarded as the main clinical symptoms. There is no biological marker, but there is considerable evidence to suggest that ADHD behavior is associated with poor dopaminergic and noradrenergic modulation of neuronal circuits that involve the frontal lobes. The best validated animal model of ADHD, the Spontaneously Hypertensive Rat (SHR), shows pronounced overactivity, impulsiveness, and deficient sustained attention. The primary objective of the present research was to investigate behavioral effects of a range of doses of chronic l-amphetamine on ADHD-like symptoms in the SHR. Methods The present study tested the behavioral effects of 0.75 and 2.2 mg l-amphetamine base/kg i.p. in male SHRs and their controls, the Wistar Kyoto rat (WKY). ADHD-like behavior was tested with a visual discrimination task measuring overactivity, impulsiveness and inattentiveness. Results The striking impulsiveness, overactivity, and poorer sustained attention seen during baseline conditions in the SHR were improved by chronic treatment with l-amphetamine. The dose-response curves were, however, different for the different behaviors. Most significantly, the 0.75 mg/kg dose of l-amphetamine improved sustained attention without reducing overactivity and impulsiveness. The 2.2 mg/kg dose improved sustained attention as well as reduced SHR overactivity and impulsiveness. Discussion The effects of l-amphetamine to reduce the behavioral symptoms of ADHD in the SHR were maintained over the 14 days of daily dosing with no evidence of tolerance developing. PMID:21450079

Chemogenetic Activation of Midbrain Dopamine Neurons Affects Attention, but not Impulsivity, in the Five-Choice Serial Reaction Time Task in Rats.

PubMed

Boekhoudt, Linde; Voets, Elisa S; Flores-Dourojeanni, Jacques P; Luijendijk, Mieneke Cm; Vanderschuren, Louk Jmj; Adan, Roger Ah

2017-05-01

Attentional impairments and exaggerated impulsivity are key features of psychiatric disorders, such as attention-deficit/hyperactivity disorder, schizophrenia, and addiction. These deficits in attentional performance and impulsive behaviors have been associated with aberrant dopamine (DA) signaling, but it remains unknown whether these deficits result from enhanced DA neuronal activity in the midbrain. Here, we took a novel approach by testing the impact of chemogenetically activating DA neurons in the ventral tegmental area (VTA) or substantia nigra pars compacta (SNc) on attention and impulsivity in the five-choice serial reaction time task (5-CSRTT) in rats. We found that activation of DA neurons in both the VTA and SNc impaired attention by increasing trial omissions. In addition, SNc DA neuron activation decreased attentional accuracy. Surprisingly, enhanced DA neuron activity did not affect impulsive action in this task. These results show that enhanced midbrain DA neuronal activity induces deficits in attentional performance, but not impulsivity. Furthermore, DA neurons in the VTA and SNc have different roles in regulating attention. These findings contribute to our understanding of the neural substrates underlying attention deficits and impulsivity, and provide valuable insights to improve treatment of these symptoms.

Coherence between tissue oxygen indexes in vastus lateralis and gastrocnemius in repetition of impulse exercise with high intensity.

PubMed

Yano, T; Widjaja, W; Shirakawa, K; Lian, C-S; Xiao, Z; Yunoki, T

2015-06-01

The purpose of this study was to determine whether tissue oxygen indices (TOIs) in two muscle groups oscillated and were synchronized in repetition of impulse exercise with high intensity. Five impulse exercises of 400 watts for 10 s were repeated with intervals of 6 min. During this period, TOI was determined by near-infrared spectroscopy in the vastus lateralis and gastrocnemius muscles. TOIs in the two muscles oscillated at rest. The TOIs rapidly decreased during each impulse exercise and then recovered and overshot after each impulse. The TOIs oscillated during each interval period. During this test period, coherent and phase differences were determined. There was high coherence between TOIs in the two muscles with a peak value at 0.019 Hz. There was a phase difference of -45 ± 32.4 degrees between TOIs in the two muscles. This phase difference corresponded to about 6 s in time scale. It seemed from this time delay that impulse exercise was not a trigger factor for the starting point of TOIs in the two muscles. It has been concluded that TOIs oscillate and are synchronized between two muscles in repetition of impulse exercise with high intensity.

Direct and Indirect Effects of Impulsivity Traits on Drinking and Driving in Young Adults

PubMed Central

Treloar, Hayley R.; Morris, David H.; Pedersen, Sarah L.; McCarthy, Denis M.

2012-01-01

Objective: Impulsivity is strongly associated with alcohol-related risk-taking behavior, and this association has been found to be mediated by alcohol cognitions. The current study expanded this literature by comparing the relative association of distinct impulsivity traits with a specific risky behavior—drinking and driving. We then tested whether drinking-and-driving expectancies uniquely mediated this relation over and above other cognitions about alcohol and drinking and driving. Method: College student drivers (n = 816; 53.6% women) completed a paper-and-pencil survey in small groups. Self-report measures assessed alcohol use, impulsivity traits, alcohol expectancies, drinking-and-driving cognitions (i.e., expectancies, attitudes, beliefs), and drinking and driving. Results: Although all impulsivity traits were correlated with drinking and driving, only urgency uniquely contributed to drinking and driving. Indirect effect tests indicated that drinking-and-driving convenience expectancies partially mediated this association as well as that between (lack of) perseverance and drinking and driving. These results remained significant after controlling for alcohol expectancies and other drinking-and-driving cognitions. Conclusions: These findings highlight the importance of distinguishing among impulsivity traits to improve theoretical models of the processes by which personality leads to specific alcohol-related consequences. In addition, results extend previous research by providing evidence for the unique importance of expectancies regarding the convenience of drinking and driving over and above more global alcohol expectancies and other drinking-and-driving cognitions. PMID:22846243

Ground Reaction Forces of the Lead and Trail Limbs when Stepping Over an Obstacle

PubMed Central

Bovonsunthonchai, Sunee; Khobkhun, Fuengfa; Vachalathiti, Roongtiwa

2015-01-01

Background Precise force generation and absorption during stepping over different obstacles need to be quantified for task accomplishment. This study aimed to quantify how the lead limb (LL) and trail limb (TL) generate and absorb forces while stepping over obstacle of various heights. Material/Methods Thirteen healthy young women participated in the study. Force data were collected from 2 force plates when participants stepped over obstacles. Two limbs (right LL and left TL) and 4 conditions of stepping (no obstacle, stepping over 5 cm, 20 cm, and 30 cm obstacle heights) were tested for main effect and interaction effect by 2-way ANOVA. Paired t-test and 1-way repeated-measure ANOVA were used to compare differences of variables between limbs and among stepping conditions, respectively. The main effects on the limb were found in first peak vertical force, minimum vertical force, propulsive peak force, and propulsive impulse. Results Significant main effects of condition were found in time to minimum force, time to the second peak force, time to propulsive peak force, first peak vertical force, braking peak force, propulsive peak force, vertical impulse, braking impulse, and propulsive impulse. Interaction effects of limb and condition were found in first peak vertical force, propulsive peak force, braking impulse, and propulsive impulse. Conclusions Adaptations of force generation in the LL and TL were found to involve adaptability to altered external environment during stepping in healthy young adults. PMID:26169293

The Role of Emotion-Driven Impulse Control Difficulties in the Relation Between Social Anxiety and Aggression.

PubMed

Dixon, Laura J; Tull, Matthew T; Lee, Aaron A; Kimbrel, Nathan A; Gratz, Kim L

2017-06-01

To enhance our understanding of the factors that may account for increased aggression in socially anxious individuals, this study examined associations among emotion-driven impulse control difficulties, social anxiety, and dimensions of aggression (i.e., hostility, anger, physical aggression, verbal aggression). Individuals (N = 107; 73.8% male; M age = 40.8 years) receiving residential substance abuse treatment participated in this cross-sectional study. Social anxiety symptoms were significantly positively correlated with emotion-driven impulse control difficulties, anger, and hostility, but not verbal or physical aggression. Separate models for each aggression facet were examined to test the direct and indirect paths. Bootstrapped mediation analyses indicated a significant indirect path from social anxiety symptoms to each facet of aggression through emotion-driven impulse control difficulties (ps < .05). Results highlight the potential utility of targeting emotion-driven impulse control difficulties to decrease aggression among socially anxious individuals. © 2016 Wiley Periodicals, Inc.

Impulse oscillometry in the evaluation of diseases of the airways in children

PubMed Central

Komarow, Hirsh D.; Myles, Ian A.; Uzzaman, Ashraf; Metcalfe, Dean D.

2012-01-01

Objective To provide an overview of impulse oscillometry and its application to the evaluation of children with diseases of the airways. Data Sources Medline and PubMed search, limited to English language and human disease, with keywords forced oscillation, impulse oscillometry, and asthma. Study Selections The opinions of the authors were used to select studies for inclusion in this review. Results Impulse oscillometry is a noninvasive and rapid technique requiring only passive cooperation by the patient. Pressure oscillations are applied at the mouth to measure pulmonary resistance and reactance. It is employed by health care professionals to help diagnose pediatric pulmonary diseases such asthma and cystic fibrosis; assess therapeutic responses; and measure airway resistance during provocation testing. Conclusions Impulse oscillometry provides a rapid, noninvasive measure of airway impedance. It may be easily employed in the diagnosis and management of diseases of the airways in children. PMID:21354020

Sex differences in succumbing to sexual temptations: a function of impulse or control?

PubMed

Tidwell, Natasha D; Eastwick, Paul W

2013-12-01

Men succumb to sexual temptations (e.g., infidelity, mate poaching) more than women. Explanations for this effect vary; some researchers propose that men and women differ in sexual impulse strength, whereas others posit a difference in sexual self-control. These studies are the first to test such underlying mechanisms. In Study 1, participants reported on their impulses and intentional control exertion when they encountered a real-life tempting but forbidden potential partner. Study 2 required participants to perform a reaction-time task in which they accepted/rejected potential partners, and we used process dissociation to separate the effects of impulse and control. In both studies, men succumbed to the sexual temptations more than women, and this sex difference emerged because men experienced stronger impulses, not because they exerted less intentional control. Implications for the integration of evolutionary and self-regulatory perspectives on sex differences are discussed.

The recovery of weak impulsive signals based on stochastic resonance and moving least squares fitting.

PubMed

Jiang, Kuosheng; Xu, Guanghua; Liang, Lin; Tao, Tangfei; Gu, Fengshou

2014-07-29

In this paper a stochastic resonance (SR)-based method for recovering weak impulsive signals is developed for quantitative diagnosis of faults in rotating machinery. It was shown in theory that weak impulsive signals follow the mechanism of SR, but the SR produces a nonlinear distortion of the shape of the impulsive signal. To eliminate the distortion a moving least squares fitting method is introduced to reconstruct the signal from the output of the SR process. This proposed method is verified by comparing its detection results with that of a morphological filter based on both simulated and experimental signals. The experimental results show that the background noise is suppressed effectively and the key features of impulsive signals are reconstructed with a good degree of accuracy, which leads to an accurate diagnosis of faults in roller bearings in a run-to failure test.

Differential effects of the pharmacological stressor yohimbine on impulsive decision making and response inhibition.

PubMed

Schippers, M C; Schetters, D; De Vries, T J; Pattij, T

2016-07-01

High levels of impulsivity have been associated with psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and substance abuse. In addition, acute stress is known to exacerbate many psychiatric symptoms in impulse control disorders. The purpose of the current study was to investigate the acute effects of the pharmacological stressor yohimbine on response inhibition and impulsive choice. A group of male rats (n = 12) was trained in the delayed reward task (DRT) to assess impulsive choice. A separate group (n = 10) was trained in the stop-signal task (SST) to measure response inhibition. Upon stable responding, the effects of yohimbine (0, 1.25, 2.5, and 5 mg/kg i.p.) were tested in a Latin square design. Acute yohimbine significantly increased the preference for the large and delayed reinforcer in the DRT, indicating a decrease in impulsive choice. On the contrary, the effect size of 1.25 mg/kg yohimbine on stop-signal reaction times correlated negatively with baseline performance, suggesting a baseline-dependent effect on response inhibition as measured in the SST. The current data suggest that the effects of the pharmacological stressor yohimbine on impulse control strongly depend on the type of impulsive behavior. Pharmacological stress decreased impulsive decision making, an observation that is in line with previously published rodent studies. By contrast, the lowest dose of yohimbine revealed a baseline-dependent effect on response inhibition. As such, the effects of yohimbine are largely comparable to the effects of psychostimulants on impulsivity and may support the notion of cross sensitization of stress and psychostimulants.

Differential effects of social and novelty enrichment on individual differences in impulsivity and behavioral flexibility.

PubMed

Wang, Maya Zhe; Marshall, Andrew T; Kirkpatrick, Kimberly

2017-06-01

Early life experience profoundly impacts behavior and cognitive functions in rats. The present study investigated how the presence of conspecifics and/or novel objects, could independently influence individual differences in impulsivity and behavioral flexibility. Twenty-four rats were reared in an isolated condition, an isolated condition with a novel object, a pair-housed social condition, or a pair-housed social condition with a novel object. The rats were then tested on an impulsive choice task, a behavioral flexibility task, and an impulsive action task. Novelty enrichment produced an overall increase in impulsive choice, while social enrichment decreased impulsive choice in the absence of novelty enrichment and also produced an overall increase in impulsive action. In the behavioral flexibility task, social enrichment increased regressive errors, whereas both social and novelty enrichment reduced never-reinforced errors. Individual differences analyses indicated a significant relationship between performance in the behavioral flexibility and impulsive action tasks, which may reflect a common psychological correlate of action inhibition. Moreover, there was a relationship between delay sensitivity in the impulsive choice task and performance on the DRL and behavioral flexibility tasks, suggesting a dual role for timing and inhibitory processes in driving the interrelationship between these tasks. Overall, these results indicate that social and novelty enrichment produce distinct effects on impulsivity and adaptability, suggesting the need to parse out the different elements of enrichment in future studies. Further research is warranted to better understand how individual differences in sensitivity to enrichment affect individuals' interactions with and the resulting consequences of the rearing environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Differential effects of social and novelty enrichment on individual differences in impulsivity and behavioral flexibility

PubMed Central

Wang, Maya Zhe; Marshall, Andrew T.; Kirkpatrick, Kimberly

2017-01-01

Early life experience profoundly impacts behavior and cognitive functions in rats. The present study investigated how the presence of conspecifics and/or novel objects, could independently influence individual differences in impulsivity and behavioral flexibility. Twenty-four rats were reared in an isolated condition, an isolated condition with a novel object, a pair-housed social condition, or a pair-housed social condition with a novel object. The rats were then tested on an impulsive choice task, a behavioral flexibility task, and an impulsive action task. Novelty enrichment produced an overall increase in impulsive choice, while social enrichment decreased impulsive choice in the absence of novelty enrichment and also produced an overall increase in impulsive action. In the behavioral flexibility task, social enrichment increased regressive errors, whereas both social and novelty enrichment reduced never reinforced errors. Individual differences analyses indicated a significant relationship between performance in the behavioral flexibility and impulsive action tasks, which may reflect a common psychological correlate of action inhibition. Moreover, there was a relationship between delay sensitivity in the impulsive choice task and performance on the DRL and behavioral flexibility tasks, suggesting a dual role for timing and inhibitory processes in driving the interrelationship between these tasks. Overall, these results indicate that social and novelty enrichment produce distinct effects on impulsivity and adaptability, suggesting the need to parse out the different elements of enrichment in future studies. Further research is warranted to better understand how individual differences in sensitivity to enrichment affect individuals’ interactions with and the resulting consequences of the rearing environment. PMID:28341610

Testing of molded high temperature plastic actuator road seals for use in advanced aircraft hydraulic systems

NASA Technical Reports Server (NTRS)

Waterman, A. W.; Huxford, R. L.; Nelson, W. G.

1976-01-01

Molded high temperature plastic first and second stage rod seal elements were evaluated in seal assemblies to determine performance characteristics. These characteristics were compared with the performance of machined seal elements. The 6.35 cm second stage Chevron seal assembly was tested using molded Chevrons fabricated from five molding materials. Impulse screening tests conducted over a range of 311 K to 478 K revealed thermal setting deficiencies in the aromatic polyimide molding materials. Seal elements fabricated from aromatic copolyester materials structurally failed during impulse cycle calibration. Endurance testing of 3.85 million cycles at 450 K using MIL-H-83283 fluid showed poorer seal performance with the unfilled aromatic polyimide material than had been attained with seals machined from Vespel SP-21 material. The 6.35 cm first stage step-cut compression loaded seal ring fabricated from copolyester injection molding material failed structurally during impulse cycle calibration. Molding of complex shape rod seals was shown to be a potentially controllable technique, but additional molding material property testing is recommended.

Whittle's "Channel One": Effects on Impulsive Preadolescents' Desire for Advertised Products.

ERIC Educational Resources Information Center

Tozzo-Lyles, Teresa A.; Walsh-Childers, Kim

A field experiment tested effects of "Channel One" commercials on impulsive preadolescent students' purchasing preferences, such as product liking and likelihood of buying regularly advertised products. A total of 67 sixth-grade middle school students participated in the field experiment. Students who viewed "Channel One' daily were…

Roles of Impulsivity, Motivation, and Emotion Regulation in Procrastination - Path Analysis and Comparison Between Students and Non-students.

PubMed

Wypych, Marek; Matuszewski, Jacek; Dragan, Wojciech Ł

2018-01-01

Procrastination - an irrational delay of intended actions despite expecting to be worse off - is a complex and non-homogenous phenomenon. Previous studies have found a number of correlates of procrastination, some of which seem to be particularly important. Impulsivity is closely connected to procrastination on behavioral, genetic, and neuronal levels. Difficulties in emotion regulation have also been shown to be strongly related to procrastination. Procrastination can also be considered as a motivation-based problem. To try to disentangle the connections of impulsivity, emotion regulation, and motivation to procrastination we collected data from over 600 subjects using multiple questionnaires (PPS - Pure Procrastination Scale; UPPSP - Impulsive Behavior Scale, ERQ - Emotion Regulation Questionnaire and MDT - Motivational Diagnostic Test). Structural equation modeling was performed to test several possible relationships between the measured variables. The effects of student status and age have also been investigated. The final path model was a directional model based on six explanatory variables and accounted for 70% of the variance in procrastination. Path analysis revealed that the strongest contributions to procrastination came from lack of value, delay discounting, and lack of perseverance, suggesting the involvement of motivation and impulsivity. The model also revealed the moderating role of expressive suppression between several aspects of impulsivity and procrastination. Close inspection of the paths' weights suggests that there may be two partly competing strategies for dealing with impulsivity and negative emotions: either to suppress emotions and impulsive reactions or to react impulsively, discarding previous plans, and to procrastinate. Path invariance analysis showed the significant moderating roles of student status and age. Both in non-students and high-age groups, the path leading from suppression to procrastination was insignificant. This suggests that caution should be used in generalizing the results of studies carried out on students. These results support previous findings that procrastination may serve as a short-term mood regulation strategy. However, as the spectrum of the emotion regulation strategies included in the study was very limited, we conclude that future studies should seek more insight into the relationship between emotion regulation, self-control, and procrastination.

Roles of Impulsivity, Motivation, and Emotion Regulation in Procrastination – Path Analysis and Comparison Between Students and Non-students

PubMed Central

Wypych, Marek; Matuszewski, Jacek; Dragan, Wojciech Ł.

2018-01-01

Procrastination – an irrational delay of intended actions despite expecting to be worse off – is a complex and non-homogenous phenomenon. Previous studies have found a number of correlates of procrastination, some of which seem to be particularly important. Impulsivity is closely connected to procrastination on behavioral, genetic, and neuronal levels. Difficulties in emotion regulation have also been shown to be strongly related to procrastination. Procrastination can also be considered as a motivation-based problem. To try to disentangle the connections of impulsivity, emotion regulation, and motivation to procrastination we collected data from over 600 subjects using multiple questionnaires (PPS – Pure Procrastination Scale; UPPSP – Impulsive Behavior Scale, ERQ – Emotion Regulation Questionnaire and MDT – Motivational Diagnostic Test). Structural equation modeling was performed to test several possible relationships between the measured variables. The effects of student status and age have also been investigated. The final path model was a directional model based on six explanatory variables and accounted for 70% of the variance in procrastination. Path analysis revealed that the strongest contributions to procrastination came from lack of value, delay discounting, and lack of perseverance, suggesting the involvement of motivation and impulsivity. The model also revealed the moderating role of expressive suppression between several aspects of impulsivity and procrastination. Close inspection of the paths’ weights suggests that there may be two partly competing strategies for dealing with impulsivity and negative emotions: either to suppress emotions and impulsive reactions or to react impulsively, discarding previous plans, and to procrastinate. Path invariance analysis showed the significant moderating roles of student status and age. Both in non-students and high-age groups, the path leading from suppression to procrastination was insignificant. This suggests that caution should be used in generalizing the results of studies carried out on students. These results support previous findings that procrastination may serve as a short-term mood regulation strategy. However, as the spectrum of the emotion regulation strategies included in the study was very limited, we conclude that future studies should seek more insight into the relationship between emotion regulation, self-control, and procrastination. PMID:29922205

Binge drinking and family history of alcoholism are associated with an altered developmental trajectory of impulsive choice across adolescence.

PubMed

Jones, Scott A; Steele, Joel S; Nagel, Bonnie J

2017-07-01

To test whether binge drinking, the density of familial alcoholism (FHD) and their interaction are associated with an altered developmental trajectory of impulsive choice across adolescence, and whether more life-time drinks are associated with a greater change in impulsive choice across age. Alcohol-naive adolescents, with varying degrees of FHD, were recruited as part of an ongoing longitudinal study on adolescent development, and were grouped based on whether they remained non-drinkers (n = 83) or initiated binge drinking (n = 33) during follow-up. During all visits, adolescents completed a monetary delay discounting task to measure impulsive choice. The effects of binge-drinking status, FHD and their interaction on impulsive choice across adolescence were tested. Developmental Brain Imaging Laboratory, Oregon Health & Science University, Portland, Oregon, USA. A total of 116 healthy male and female adolescents (ages 10-17 years at baseline) completed two to four visits between July 2008 and May 2016. Discounting rates were obtained based on adolescents' preference for immediate or delayed rewards. FHD was based on parent-reported prevalence of alcohol use disorder in the participant's first- and second-degree relatives. Binge-drinking status was determined based on the number of recent binge-drinking episodes. There was a significant interaction effect of binge-drinking status and FHD on impulsive choice across age (b = 1.090, P < 0.05, β = 0.298). In adolescents who remained alcohol-naive, greater FHD was associated with a steeper decrease in discounting rates across adolescence (b = -0.633, P < 0.05, β = -0.173); however, this effect was not present in binge-drinkers. Furthermore, total life-time drinks predicted escalated impulsive choice (b = 0.002, P < 0.05, β = 0.295) in binge-drinking adolescents. A greater degree of familial alcoholism is associated with a steeper decline in impulsive choice across adolescence, but only in those who remain alcohol-naive. Meanwhile, more life-time drinks during adolescence is associated with increases in impulsive choice across age. © 2017 Society for the Study of Addiction.

Interindividual differences in cognitive flexibility: influence of gray matter volume, functional connectivity and trait impulsivity

PubMed Central

Langner, Robert; Cieslik, Edna C.; Rottschy, Claudia; Eickhoff, Simon B.

2016-01-01

Cognitive flexibility, a core aspect of executive functioning, is required for the speeded shifting between different tasks and sets. Using an interindividual differences approach, we examined whether cognitive flexibility, as assessed by the Delis–Kaplan card-sorting test, is associated with gray matter volume (GMV) and functional connectivity (FC) of regions of a core network of multiple cognitive demands as well as with different facets of trait impulsivity. The core multiple-demand network was derived from three large-scale neuroimaging meta-analyses and only included regions that showed consistent associations with sustained attention, working memory as well as inhibitory control. We tested to what extent self-reported impulsivity as well as GMV and resting-state FC in this core network predicted cognitive flexibility independently and incrementally. Our analyses revealed that card-sorting performance correlated positively with GMV of the right anterior insula, FC between bilateral anterior insula and midcingulate cortex/supplementary motor area as well as the impulsivity dimension “Premeditation.” Importantly, GMV, FC and impulsivity together accounted for more variance of card-sorting performance than every parameter alone. Our results therefore indicate that various factors contribute individually to cognitive flexibility, underlining the need to search across multiple modalities when aiming to unveil the mechanisms behind executive functioning. PMID:24878823

Cognitive task performance and frequency of alcohol usage in young adults.

PubMed

Harvanko, Arit M; Odlaug, Brian L; Schreiber, Liana R N; Grant, Jon E

2012-06-01

The goal of our study was to examine cognitive effects of alcohol in young adults at varied levels of alcohol usage using well-validated computerized cognitive measures. One hundred fifty-five young adults (mean age: 21.15 ± 3.092 years; 25.8% female), free from non-alcohol-related psychiatric diagnoses and drug use, underwent selected tests from the Cambridge Neuropsychological Test Automated Battery in conjunction with the Barratt Impulsivity Scale, Eysenck Impulsivity Questionnaire, and the Tridimensional Personality Questionnaire. Study participants were grouped according to alcohol frequency: nondrinkers, at-risk drinkers (subsyndromal alcohol usage), and alcohol use disorder. At-risk drinkers and individuals with alcohol use disorders bet significantly more overall on the Cambridge Gambling Task than nondrinkers. There were no significant differences noted between groups on the Spatial Working Memory task or Intra-dimensional/Extra-dimensional Set Shift task. Individuals with alcohol use disorders endorsed higher impulsivity than at-risk and nondrinkers on the Barratt Impulsivity Scale and Eysenck Impulsivity Questionnaire. Individuals with alcohol use disorders and at-risk drinkers also endorsed higher venturesomeness than nondrinkers on the Tridimensional Personality Questionnaire. Results from the Cambridge Gambling Task suggest that even at a subsyndromal level, young adults make risky decisions that mirror those seen in individuals with alcohol use disorders.

Lethal obesity associated with sodium valproate in a brain-injured patient.

PubMed

Black, Deborah N; Althoff, Robert R; Daye, Kathleen; Pelletier, Corinne A

2005-06-01

A 34-year-old man developed posttraumatic epilepsy and a disinhibited orbitofrontal syndrome following severe head trauma at age 22. After an 11-year prison term marked by repeated impulsive aggression, he was transferred to a state psychiatric hospital. Replacement of phenytoin by valproic acid resulted in a 100-lb weight gain, exacerbation of sleep apnea, and right heart failure. Despite replacement of valproate with topiramate, he died of a cardiorespiratory arrest during a seizure. This case illustrates the potential risks associated with valproate therapy in the obese brain-damaged population.

PHOTOELECTRIC CONTROL FOR TAPE POSITIONING

DOEpatents

Woody, J.W. Jr.

1961-07-25

A control system is described for producing control impulses which may be used to start, stop, and position a magnetic tape with respect to a transducer, and to locate discrete areas on the tape. Means are provided for positive identification of data blocks, exact positioning of the tape under the magnetic head, drive in either direction, accurate skip-over of imperfect regions of the tape, stopping the tape if equipment malfunction results in a failure to detect the block-identifying signals, and starting and stopping those parts of the tape between of the tape drive clutches.

Probing the microscopic corrugation of liquid surfaces with gas-liquid collisions

NASA Technical Reports Server (NTRS)

King, Mackenzie E.; Nathanson, Gilbert M.; Hanning-Lee, Mark A.; Minton, Timothy K.

1993-01-01

We have measured the directions and velocities of Ne, Ar, and Xe atoms scattering from perfluorinated ether and hydrocarbon liquids to probe the relationship between the microscopic roughness of liquid surfaces and gas-liquid collision dynamics. Impulsive energy transfer is governed by the angle of deflection: head-on encounters deposit more energy than grazing collisions. Many atoms scatter in the forward direction, particularly at glancing incidence. These results imply that the incoming atoms recoil locally from protruding C-H and C-F groups in hard spherelike collisions.

A MAOA gene*cocaine severity interaction on impulsivity and neuropsychological measures of orbitofrontal dysfunction: preliminary results.

PubMed

Verdejo-García, Antonio; Albein-Urios, Natalia; Molina, Esther; Ching-López, Ana; Martínez-González, José M; Gutiérrez, Blanca

2013-11-01

Based on previous evidence of a MAOA gene*cocaine use interaction on orbitofrontal cortex volume attrition, we tested whether the MAOA low activity variant and cocaine use severity are interactively associated with impulsivity and behavioral indices of orbitofrontal dysfunction: emotion recognition and decision-making. 72 cocaine dependent individuals and 52 non-drug using controls (including healthy individuals and problem gamblers) were genotyped for the MAOA gene and tested using the UPPS-P Impulsive Behavior Scale, the Iowa Gambling Task and the Ekman's Facial Emotions Recognition Test. To test the main hypothesis, we conducted hierarchical multiple regression analyses including three sets of predictors: (1) age, (2) MAOA genotype and severity of cocaine use, and (3) the interaction between MAOA genotype and severity of cocaine use. UPPS-P, Ekman Test and Iowa Gambling Task's scores were the outcome measures. We computed the statistical significance of the prediction change yielded by each consecutive set, with 'a priori' interest in the MAOA*cocaine severity interaction. We found significant effects of the MAOA gene*cocaine use severity interaction on the emotion recognition scores and the UPPS-P's dimensions of Positive Urgency and Sensation Seeking: Low activity carriers with higher cocaine exposure had poorer emotion recognition and higher Positive Urgency and Sensation Seeking. Cocaine users carrying the MAOA low activity show a greater impact of cocaine use on impulsivity and behavioral measures of orbitofrontal cortex dysfunction. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Increased self-reported impulsivity in methamphetamine users maintaining drug abstinence.

PubMed

Jones, Hannah W; Dean, Andy C; Price, Kimberly A; London, Edythe D

2016-09-01

Impulsivity has been proposed as an important factor in the initiation and maintenance of addiction. Indirect evidence suggests that some methamphetamine users report less impulsivity when they are using methamphetamine compared to when abstaining from drug use, but this hypothesis has not been directly tested. In this study, self-reports of impulsivity were obtained from 32 methamphetamine-dependent (DSM-IV) research participants and 41 healthy control subjects, using the Barratt Impulsiveness Scale-11. The methamphetamine users were assessed during an active period of methamphetamine use, as determined through urinalysis, and again after approximately 1 week of confirmed abstinence. Control subjects likewise completed two assessments. A subset of participants also completed serial assessments of the Beck Depression Inventory (Methamphetamine Group, N = 17, Control Group, N = 38) and the Methamphetamine Withdrawal Questionnaire (Methamphetamine Group, N = 12). There was a significant interaction of group with time on impulsivity (p = 0.044), reflecting a significant increase from the first to the second assessment in the methamphetamine users (p = 0.013), but no change among healthy control subjects. In contrast, depressive and withdrawal symptoms significantly decreased between the first and second assessments in the methamphetamine users (ps ≤0.01). Change in impulsivity in methamphetamine users was not significantly correlated with change in withdrawal or depression (ps >0.05). These findings suggest that methamphetamine users report more impulsivity when abstaining from drug use, an effect that is not significantly related to methamphetamine withdrawal. Attenuation of impulsivity may reinforce continued methamphetamine use in these individuals.

Cued to Act on Impulse: More Impulsive Choice and Risky Decision Making by Women Susceptible to Overeating after Exposure to Food Stimuli.

PubMed

Yeomans, Martin R; Brace, Aaron

2015-01-01

There is increasing evidence that individual differences in tendency to overeat relate to impulsivity, possibly by increasing reactivity to food-related cues in the environment. This study tested whether acute exposure to food cues enhanced impulsive and risky responses in women classified on tendency to overeat, indexed by scores on the three factor eating questionnaire disinhibition (TFEQ-D), restraint (TFEQ-R) and hunger scales. Ninety six healthy women completed two measures of impulsive responding (delayed discounting, DDT and a Go No-Go, GNG, task) and a measure of risky decision making (the balloon analogue risk task, BART) as well as questionnaire measures of impulsive behaviour either after looking at a series of pictures of food or visually matched controls. Impulsivity (DDT) and risk-taking (BART) were both positively associated with TFEQ-D scores, but in both cases this effect was exacerbated by prior exposure to food cues. No effects of restraint were found. TFEQ-D scores were also related to more commission errors on the GNG, while restrained women were slower on the GNG, but neither effect was modified by cue exposure. Overall these data suggest that exposure to food cues act to enhance general impulsive responding in women at risk of overeating and tentatively suggest an important interaction between tendency for impulsive decision making and food cues that may help explain a key underlying risk factor for overeating.

Cued to Act on Impulse: More Impulsive Choice and Risky Decision Making by Women Susceptible to Overeating after Exposure to Food Stimuli

PubMed Central

Yeomans, Martin R.; Brace, Aaron

2015-01-01

There is increasing evidence that individual differences in tendency to overeat relate to impulsivity, possibly by increasing reactivity to food-related cues in the environment. This study tested whether acute exposure to food cues enhanced impulsive and risky responses in women classified on tendency to overeat, indexed by scores on the three factor eating questionnaire disinhibition (TFEQ-D), restraint (TFEQ-R) and hunger scales. Ninety six healthy women completed two measures of impulsive responding (delayed discounting, DDT and a Go No-Go, GNG, task) and a measure of risky decision making (the balloon analogue risk task, BART) as well as questionnaire measures of impulsive behaviour either after looking at a series of pictures of food or visually matched controls. Impulsivity (DDT) and risk-taking (BART) were both positively associated with TFEQ-D scores, but in both cases this effect was exacerbated by prior exposure to food cues. No effects of restraint were found. TFEQ-D scores were also related to more commission errors on the GNG, while restrained women were slower on the GNG, but neither effect was modified by cue exposure. Overall these data suggest that exposure to food cues act to enhance general impulsive responding in women at risk of overeating and tentatively suggest an important interaction between tendency for impulsive decision making and food cues that may help explain a key underlying risk factor for overeating. PMID:26378459

Testing and evaluation of the LES-6 pulsed plasma thruster by means of a torsion pendulum system

NASA Technical Reports Server (NTRS)

Hamidian, J. P.; Dahlgren, J. B.

1973-01-01

Performance characteristics of the LES-6 pulsed plasma thruster over a range of input conditions were investigated by means of a torsion pendulum system. Parameters of particular interest included the impulse bit and time average thrust (and their repeatability), specific impulse, mass ablated per discharge, specific thrust, energy per unit area, efficiency, and variation of performance with ignition command rate. Intermittency of the thruster as affected by input energy and igniter resistance were also investigated. Comparative experimental data correlation with the data presented. The results of these tests indicate that the LES-6 thruster, with some identifiable design improvements, represents an attractive reaction control thruster for attitude contol applications on long-life spacecraft requiring small metered impulse bits for precise pointing control of science instruments.

Fatty acid amide supplementation decreases impulsivity in young adult heavy drinkers

PubMed Central

van Kooten, Maria J.; Veldhuizen, Maria G.; de Araujo, Ivan E.; O’Malley, Stephanie; Small, Dana M.

2016-01-01

Compromised dopamine signaling in the striatum has been associated with the expression of impulsive behaviors in addiction, obesity and alcoholism. In rodents, Intragastric infusion of the fatty acid amide oleoylethanolamide increases striatal extracellular dopamine levels via vagal afferent signaling. Here we tested whether supplementation with PhosphoLean™, a dietary supplement that contains the precursor of the fatty acid amide oleoylethanolamide (N-oleyl-phosphatidylethanolamine), would reduce impulsive responding and alcohol use in heavy drinking young adults. Twenty-two individuals were assigned to a three-week supplementation regimen with PhosphoLean™ or placebo. Impulsivity was assessed with self-report questionnaires and behavioral tasks pre- and post-supplementation. Although self-report measures of impulsivity did not change, supplementation with PhosphoLean™, but not placebo, significantly reduced false alarm rate on a Go/No-Go task. In addition, an association was found between improved sensitivity on the Go/No-Go task and reduced alcohol intake. These findings provide preliminary evidence that promoting fatty acid derived gut-brain dopamine communication may have therapeutic potential for reducing impulsivity in heavy drinkers. PMID:26656766

Sensation seeking and impulsive traits as personality endophenotypes for antisocial behavior: Evidence from two independent samples

PubMed Central

Mann, Frank D.; Engelhardt, Laura; Briley, Daniel A.; Grotzinger, Andrew D.; Patterson, Megan W.; Tackett, Jennifer L.; Strathan, Dixie B.; Heath, Andrew; Lynskey, Michael; Slutske, Wendy; Martin, Nicholas G.; Tucker-Drob, Elliot M.; Harden, K. Paige

2017-01-01

Sensation seeking and impulsivity are personality traits that are correlated with risk for antisocial behavior (ASB). This paper uses two independent samples of twins to (a) test the extent to which sensation seeking and impulsivity statistically mediate genetic influence on ASB, and (b) compare this to genetic influences accounted for by other personality traits. In Sample 1, delinquent behavior, as well as impulsivity, sensation seeking and Big Five personality traits, were measured in adolescent twins from the Texas Twin Project. In Sample 2, adult twins from the Australian Twin Registry responded to questionnaires that assessed individual differences in Eysenck's and Cloninger's personality dimensions, and a structured telephone interview that asked participants to retrospectively report DSM-defined symptoms of conduct disorder. Bivariate quantitative genetic models were used to identify genetic overlap between personality traits and ASB. Across both samples, novelty/sensation seeking and impulsive traits accounted for larger portions of genetic variance in ASB than other personality traits. We discuss whether sensation seeking and impulsive personality are causal endophenotypes for ASB, or merely index genetic liability for ASB. PMID:28824215

Impulse generation by detonation tubes

NASA Astrophysics Data System (ADS)

Cooper, Marcia Ann

Impulse generation with gaseous detonation requires conversion of chemical energy into mechanical energy. This conversion process is well understood in rocket engines where the high pressure combustion products expand through a nozzle generating high velocity exhaust gases. The propulsion community is now focusing on advanced concepts that utilize non-traditional forms of combustion like detonation. Such a device is called a pulse detonation engine in which laboratory tests have proven that thrust can be achieved through continuous cyclic operation. Because of poor performance of straight detonation tubes compared to conventional propulsion systems and the success of using nozzles on rocket engines, the effect of nozzles on detonation tubes is being investigated. Although previous studies of detonation tube nozzles have suggested substantial benefits, up to now there has been no systematic investigations over a range of operating conditions and nozzle configurations. As a result, no models predicting the impulse when nozzles are used exist. This lack of data has severely limited the development and evaluation of models and simulations of nozzles on pulse detonation engines. The first experimental investigation measuring impulse by gaseous detonation in plain tubes and tubes with nozzles operating in varying environment pressures is presented. Converging, diverging, and converging-diverging nozzles were tested to determine the effect of divergence angle, nozzle length, and volumetric fill fraction on impulse. The largest increases in specific impulse, 72% at an environment pressure of 100 kPa and 43% at an environment pressure of 1.4 kPa, were measured with the largest diverging nozzle tested that had a 12° half angle and was 0.6 m long. Two regimes of nozzle operation that depend on the environment pressure are responsible for these increases and were first observed from these data. To augment this experimental investigation, all data in the literature regarding partially filled detonation tubes was compiled and analyzed with models investigating concepts of energy conservation and unsteady gas dynamics. A model to predict the specific impulse was developed for partially filled tubes. The role of finite chemical kinetics in detonation products was examined through numerical simulations of the flow in nonsteady expansion waves.

Associations between impulsivity, aggression, and suicide in Chinese college students

PubMed Central

2014-01-01

Background Although there are accumulating data regarding the epidemiology of suicide in China, there are meager data on suicidal ideation and attempts among college students. Interestingly, elevated impulsivity is thought to facilitate the transition from suicidal thoughts to suicidal behavior. Therefore, the objective of this research was to identify the associations between suicide and the personality factors of impulsivity and aggression. Methods This study’s sampling method employed stratified random cluster sampling. A multi-stage stratified sampling procedure was used to select participants (n = 5,245). We conducted structured interviews regarding a range of socio-demographic characteristics and suicidal morbidity. The Patient Health Questionnaire depression module (PHQ-9) was used to acquire the information about thoughts of being better off dead or hurting themselves in some ways during the past two weeks. The impulsivity symptoms in this study were assessed with the BIS-11-CH (i.e., the Chinese version of the BIS-11), and the Aggressive symptoms were assessed with the BAQ. The statistical package for social science (SPSS) v.13.0 program (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. Socio-demographic variables such as ethnic and gender were compared between groups, through the use of χ2 tests. The nonparametric test (k Independent Sample test, Kruskal-Wallis H) was performed to determine differences between the personality factors of impulsivity and aggression and suicide. Results In total, 9.1% (n = 479) of the 5,245 students reported they have ever thought about committing suicide; and 1% (n = 51) reported a history of attempted suicide (attempters). The analyses detected significant differences in scores on cognitive impulsivity (p < 0.01), when comparing individuals who only had suicidal ideation and individuals who had attempted suicide. Moreover, significant differences were found between ideators only and attempters on scores of self-oriented attack (p < .001). Conclusions Suicidal ideation is prevalent among Chinese university students. Students with high aggression scores were more susceptible to committing suicide. Scores on self-oriented attack and cognitive impulsivity may be important factors for differentially predicting suicide ideation and suicide attempts. PMID:24894449

Associations between impulsivity, aggression, and suicide in Chinese college students.

PubMed

Wang, Lin; He, Chang Zhi; Yu, Yun Miao; Qiu, Xiao Hui; Yang, Xiu Xian; Qiao, Zheng Xue; Sui, Hong; Zhu, Xiong Zhao; Yang, Yan Jie

2014-06-03

Although there are accumulating data regarding the epidemiology of suicide in China, there are meager data on suicidal ideation and attempts among college students. Interestingly, elevated impulsivity is thought to facilitate the transition from suicidal thoughts to suicidal behavior. Therefore, the objective of this research was to identify the associations between suicide and the personality factors of impulsivity and aggression. This study's sampling method employed stratified random cluster sampling. A multi-stage stratified sampling procedure was used to select participants (n = 5,245). We conducted structured interviews regarding a range of socio-demographic characteristics and suicidal morbidity. The Patient Health Questionnaire depression module (PHQ-9) was used to acquire the information about thoughts of being better off dead or hurting themselves in some ways during the past two weeks. The impulsivity symptoms in this study were assessed with the BIS-11-CH (i.e., the Chinese version of the BIS-11), and the Aggressive symptoms were assessed with the BAQ. The statistical package for social science (SPSS) v.13.0 program (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. Socio-demographic variables such as ethnic and gender were compared between groups, through the use of χ2 tests. The nonparametric test (k Independent Sample test, Kruskal-Wallis H) was performed to determine differences between the personality factors of impulsivity and aggression and suicide. In total, 9.1% (n = 479) of the 5,245 students reported they have ever thought about committing suicide; and 1% (n = 51) reported a history of attempted suicide (attempters). The analyses detected significant differences in scores on cognitive impulsivity (p < 0.01), when comparing individuals who only had suicidal ideation and individuals who had attempted suicide. Moreover, significant differences were found between ideators only and attempters on scores of self-oriented attack (p < .001). Suicidal ideation is prevalent among Chinese university students. Students with high aggression scores were more susceptible to committing suicide. Scores on self-oriented attack and cognitive impulsivity may be important factors for differentially predicting suicide ideation and suicide attempts.

High-Performance Bipropellant Engine

NASA Technical Reports Server (NTRS)

Biaglow, James A.; Schneider, Steven J.

1999-01-01

TRW, under contract to the NASA Lewis Research Center, has successfully completed over 10 000 sec of testing of a rhenium thrust chamber manufactured via a new-generation powder metallurgy. High performance was achieved for two different propellants, N2O4- N2H4 and N2O4 -MMH. TRW conducted 44 tests with N2O4-N2H4, accumulating 5230 sec of operating time with maximum burn times of 600 sec and a specific impulse Isp of 333 sec. Seventeen tests were conducted with N2O4-MMH for an additional 4789 sec and a maximum Isp of 324 sec, with a maximum firing duration of 700 sec. Together, the 61 tests totalled 10 019 sec of operating time, with the chamber remaining in excellent condition. Of these tests, 11 lasted 600 to 700 sec. The performance of radiation-cooled rocket engines is limited by their operating temperature. For the past two to three decades, the majority of radiation-cooled rockets were composed of a high-temperature niobium alloy (C103) with a disilicide oxide coating (R512) for oxidation resistance. The R512 coating practically limits the operating temperature to 1370 C. For the Earth-storable bipropellants commonly used in satellite and spacecraft propulsion systems, a significant amount of fuel film cooling is needed. The large film-cooling requirement extracts a large penalty in performance from incomplete mixing and combustion. A material system with a higher temperature capability has been matured to the point where engines are being readied for flight, particularly the 100-lb-thrust class engine. This system has powder rhenium (Re) as a substrate material with an iridium (Ir) oxidation-resistant coating. Again, the operating temperature is limited by the coating; however, Ir is capable of long-life operation at 2200 C. For Earth-storable bipropellants, this allows for the virtual elimination of fuel film cooling (some film cooling is used for thermal control of the head end). This has resulted in significant increases in specific impulse performance (15 to 20 sec). To determine the merits of a powder rhenium thrust chamber, Lewis On-Board Propulsion Branch directed TRW (under the Space Storable Rocket Technology Program and the High Pressure Earth Storable Rocket Technology Program) to design, fabricate, and test an engineering model to serve as a technology demonstrator.

Subchronic administration of atomoxetine causes an enduring reduction in context-induced relapse to cocaine seeking without affecting impulsive decision making.

PubMed

Broos, Nienke; Loonstra, Rhianne; van Mourik, Yvar; Schetters, Dustin; Schoffelmeer, Anton N M; Pattij, Tommy; De Vries, Taco J

2015-07-01

Previous work has established a robust relationship between impulsivity and addiction, and revealed that impulsive decision making predisposes the vulnerability to cocaine-seeking behavior in rats. An important next step is to assess whether elevated relapse vulnerability can be treated via the reduction of impulsive decision making. Therefore, this study explored whether subchronic atomoxetine treatment can reduce relapse vulnerability by reducing impulsive decision making. Rats were trained in the delayed reward task and were subjected to 3 weeks of cocaine self-administration. Following drug self-administration, animals were divided to different experimental groups and received the noradrenaline transporter inhibitor and attention-deficit/hyperactivity disorder drug atomoxetine or vehicle subchronically for 20 days. On days 1 and 10 after treatment cessation, a context-induced reinstatement test was performed. Throughout the entire experiment, changes in impulsive decision making were continuously monitored. Subchronic treatment with atomoxetine reduced context-induced reinstatement both 1 and 10 days after treatment cessation, only in animals receiving no extinction training. Interestingly, neither subchronic nor acute atomoxetine treatments affected impulsive decision making. Our data indicate that the enduring reduction in relapse sensitivity by atomoxetine occurred independent of a reduction in impulsive decision making. Nonetheless, repeated atomoxetine administration seems a promising pharmacotherapeutical strategy to prevent relapse to cocaine seeking in abstinent drug-dependent subjects. © 2014 Society for the Study of Addiction.

Assessing the Relationship between Disordered Gamblers with Psychosis and Increased Gambling Severity: The Mediating Role of Impulsivity.

PubMed

Kim, Hyoun S; Cassetta, Briana D; Hodgins, David C; Tomfohr-Madsen, Lianne M; McGrath, Daniel S; Tavares, Hermano

2018-06-01

Recent research suggests that disordered gambling and psychosis co-occur at higher rates than expected in the general population. Gamblers with psychosis also report greater psychological distress and increased gambling severity. However, the mechanism by which psychosis leads to greater gambling symptomology remains unknown. The objective of the present research was to test whether impulsivity mediated the relationship between comorbid psychosis and gambling severity. The sample consisted of 394 disordered gamblers voluntarily seeking treatment at a large university hospital in São Paulo, Brazil. A semistructured clinical interview (Mini-International Neuropsychiatric Interview) was used to diagnosis the presence of psychosis by registered psychiatrists. Severity of gambling symptoms was assessed using the Gambling Symptom Assessment Scale, and the Barratt Impulsiveness Scale-11 provided a measure of impulsivity. Of the sample, 7.2% met diagnostic criteria for psychosis. Individuals with a dual diagnosis of psychosis did not report greater gambling severity. Conversely, dual diagnoses of psychosis were associated with greater levels of impulsivity. Higher levels of impulsivity were also associated with greater gambling severity. Importantly, support for our hypothesised mediation model was found such that impulsivity mediated the association between disordered gambling and psychosis and gambling severity. Impulsivity appears to be a transdiagnostic process that may be targeted in treatment among disordered gamblers with a dual diagnosis of psychosis to reduce problematic gambling behaviours.

Nucleus accumbens core lesions induce sub-optimal choice and reduce sensitivity to magnitude and delay in impulsive choice tasks

PubMed Central

Steele, Catherine C.; Peterson, Jennifer R.; Marshall, Andrew T.; Stuebing, Sarah L.; Kirkpatrick, Kimberly

2017-01-01

The nucleus accumbens core (NAc) has long been recognized as an important contributor to the computation of reward value that is critical for impulsive choice behavior. Impulsive choice refers to choosing a smaller-sooner (SS) over a larger-later (LL) reward when the LL is more optimal in terms of the rate of reward delivery. Two experiments examined the role of the NAc in impulsive choice and its component processes of delay and magnitude processing. Experiment 1 delivered an impulsive choice task with manipulations of LL reward magnitude, followed by a reward magnitude discrimination task. Experiment 2 tested impulsive choice under manipulations of LL delay, followed by temporal bisection and progressive interval tasks. NAc lesions, in comparison to sham control lesions, produced suboptimal preferences that resulted in lower reward earning rates, and led to reduced sensitivity to magnitude and delay within the impulsive choice task. The secondary tasks revealed intact reward magnitude and delay discrimination abilities, but the lesion rats persisted in responding more as the progressive interval increased during the session. The results suggest that the NAc is most critical for demonstrating good sensitivity to magnitude and delay, and adjusting behavior accordingly. Ultimately, the NAc lesions induced suboptimal choice behavior rather than simply promoting impulsive choice, suggesting that an intact NAc is necessary for optimal decision making. PMID:29146281

Subthalamic nucleus stimulation influences expression and suppression of impulsive behaviour in Parkinson’s disease

PubMed Central

Ridderinkhof, K. Richard; Elias, William J.; Frysinger, Robert C.; Bashore, Theodore R.; Downs, Kara E.; van Wouwe, Nelleke C.; van den Wildenberg, Wery P. M.

2010-01-01

Past studies show beneficial as well as detrimental effects of subthalamic nucleus deep-brain stimulation on impulsive behaviour. We address this paradox by investigating individuals with Parkinson’s disease treated with subthalamic nucleus stimulation (n = 17) and healthy controls without Parkinson’s disease (n = 17) on performance in a Simon task. In this reaction time task, conflict between premature response impulses and goal-directed action selection is manipulated. We applied distributional analytic methods to separate the strength of the initial response impulse from the proficiency of inhibitory control engaged subsequently to suppress the impulse. Patients with Parkinson’s disease were tested when stimulation was either turned on or off. Mean conflict interference effects did not differ between controls and patients, or within patients when stimulation was on versus off. In contrast, distributional analyses revealed two dissociable effects of subthalamic nucleus stimulation. Fast response errors indicated that stimulation increased impulsive, premature responding in high conflict situations. Later in the reaction process, however, stimulation improved the proficiency with which inhibitory control was engaged to suppress these impulses selectively, thereby facilitating selection of the correct action. This temporal dissociation supports a conceptual framework for resolving past paradoxical findings and further highlights that dynamic aspects of impulse and inhibitory control underlying goal-directed behaviour rely in part on neural circuitry inclusive of the subthalamic nucleus. PMID:20861152

Development of medical electronic devices in the APL space department

NASA Technical Reports Server (NTRS)

Newman, A. L.

1985-01-01

Several electronic devices for automatically correcting specific defects in a body's physiologic regulation and allowing approximately normal functioning are described. A self-injurious behavior inhibiting system (SIBIS) is fastened to the arm of a person with chronic self-injurious behavior patterns. An electric shock is delivered into the arm whenever the device senses above-threshold acceleration of the head such as occur with head-bangers. Sounding a buzzer tone with the shock eventually allows transference of the aversive stimulus to the buzzer so shocks are no longer necessary. A programmable implantable medication system features a solenoid pump placed beneath the skin and refueled by hypodermic needle. The pump functions are programmable and can deliver insulin, chemotherapy mixes and/or pain killers according to a preset schedule or on patient demand. Finally, an automatic implantible defibrillator has four electrodes attached directly to the heart for sensing electrical impulses or emitting them in response to cardiac fibrillation.

Beamforming synthesis of binaural responses from computer simulations of acoustic spaces.

PubMed

Poletti, Mark A; Svensson, U Peter

2008-07-01

Auditorium designs can be evaluated prior to construction by numerical modeling of the design. High-accuracy numerical modeling produces the sound pressure on a rectangular grid, and subjective assessment of the design requires auralization of the sampled sound field at a desired listener position. This paper investigates the production of binaural outputs from the sound pressure at a selected number of grid points by using a least squares beam forming approach. Low-frequency axisymmetric emulations are derived by assuming a solid sphere model of the head, and a spherical array of 640 microphones is used to emulate ten measured head-related transfer function (HRTF) data sets from the CIPIC database for half the audio bandwidth. The spherical array can produce high-accuracy band-limited emulation of any human subject's measured HRTFs for a fixed listener position by using individual sets of beam forming impulse responses.

An Open-Label, Randomized Trial of Methylphenidate and Atomoxetine Treatment in Children with Attention-Deficit/Hyperactivity Disorder.

PubMed

Shang, Chi-Yung; Pan, Yi-Lei; Lin, Hsiang-Yuan; Huang, Lin-Wan; Gau, Susan Shur-Fen

2015-09-01

The efficacy of both methylphenidate and atomoxetine has been established in placebo-controlled trials. The present study aimed to directly compare the efficacy of methylphenidate and atomoxetine in improving symptoms among children with attention-deficit/hyperactivity disorder (ADHD). The study sample included 160 drug-naïve children and adolescents 7-16 years of age, with DSM-IV-defined ADHD, randomly assigned to osmotic-release oral system methylphenidate (OROS-methylphenidate) (n=80) and atomoxetine (n=80) in a 24 week, open-label, head-to-head clinical trial. The primary efficacy measure was the score of the ADHD Rating Scale-IV Parents Version: Investigator Administered and Scored (ADHD-RS-IV). The secondary efficacy measures included the Clinical Global Impressions-ADHD-Severity (CGI-ADHD-S) and Chinese Swanson, Nolan, and Pelham IV scale (SNAP-IV), based on the ratings of investigators, parents, teachers, and subjects. At week 24, mean changes in ADHD-RS-IV Inattention scores were 13.58 points (Cohen's d, -3.08) for OROS-methylphenidate and 12.65 points (Cohen's d, -3.05) for atomoxetine; and mean changes in ADHD-RS-IV Hyperactivity-Impulsivity scores were 10.16 points (Cohen's d, -1.75) for OROS-methylphenidate and 10.68 points (Cohen's d, -1.87) for atomoxetine. In terms of parent-, teacher-, and self-ratings on behavioral symptoms, both of the two treatment groups significantly decreased on the SNAP-IV scores at the end-point, with effect sizes ranging from 0.9 to 0.96 on the Inattention subscale and from 0.61 to 0.8 on the Hyperactivity/Impulsivity subscale for OROS-methylphenidate; and from 0.51 to 0.88 on the Inattention subscale and from 0.29 to 0.57 on the Hyperactivity/Impulsivity subscale for atomoxetine. No statistically significant differences between treatment groups were observed on the outcome measures. Vomiting, somnolence, and dizziness were reported more often for atomoxetine than for OROS-methylphenidate, whereas insomnia was reported more often for OROS-methylphenidate than for atomoxetine. After 24 weeks of treatment, OROS-methylphenidate and atomoxetine had comparable efficacy in reducing core ADHD symptoms in drug-naïve children and adolescents with ADHD.

Metacognition and the Development of Strategic Skills in Impulsive and Reflective Children.

ERIC Educational Resources Information Center

Kurtz, Beth E.; Borkowski, John G.

Examined were relationships between metamemory and strategic behavior in 130 impulsive and reflective children in fourth, fifth, and sixth grades. Of these, 77 had been tested 3 years earlier on multiple metamemory and memory tasks. At pretraining, children were assessed on metamemory, cognitive tempo, summarization skills, and teacher ratings of…

Selective Attention of Impulsive and Reflective Children. Research Report No. 66.

ERIC Educational Resources Information Center

Egeland, Byron; Thibodeau, Anne

The present investigation looked at selective attention in impulsive and reflective children using a central/incidental task similar to that used by Hagen, 1967. In order to examine developmental change in selective attention, children at kindergarten, second, and fifth grades were tested. The central recall task involved presenting the child with…

Cognitive Processes in the Reflective-Impulsive Cognitive Style

ERIC Educational Resources Information Center

Rozencwajg, Paulette; Corroyer, Denis

2005-01-01

In this study, the authors improved the understanding of the cognitive processes underlying the reflective-impulsive cognitive style (RI), which was initially measured by J. Kagan, B. L. Rosman, D. Day, J. Albert, and W. Phillips (1964) on the Matching Familiar Figures Test (MFFT). The authors determined the relationships between the RI style and…

Short-term Internet search using makes people rely on search engines when facing unknown issues.

PubMed

Wang, Yifan; Wu, Lingdan; Luo, Liang; Zhang, Yifen; Dong, Guangheng

2017-01-01

The Internet search engines, which have powerful search/sort functions and ease of use features, have become an indispensable tool for many individuals. The current study is to test whether the short-term Internet search training can make people more dependent on it. Thirty-one subjects out of forty subjects completed the search training study which included a pre-test, a six-day's training of Internet search, and a post-test. During the pre- and post- tests, subjects were asked to search online the answers to 40 unusual questions, remember the answers and recall them in the scanner. Un-learned questions were randomly presented at the recalling stage in order to elicited search impulse. Comparing to the pre-test, subjects in the post-test reported higher impulse to use search engines to answer un-learned questions. Consistently, subjects showed higher brain activations in dorsolateral prefrontal cortex and anterior cingulate cortex in the post-test than in the pre-test. In addition, there were significant positive correlations self-reported search impulse and brain responses in the frontal areas. The results suggest that a simple six-day's Internet search training can make people dependent on the search tools when facing unknown issues. People are easily dependent on the Internet search engines.

Short-term Internet search using makes people rely on search engines when facing unknown issues

PubMed Central

Wang, Yifan; Wu, Lingdan; Luo, Liang; Zhang, Yifen

2017-01-01

The Internet search engines, which have powerful search/sort functions and ease of use features, have become an indispensable tool for many individuals. The current study is to test whether the short-term Internet search training can make people more dependent on it. Thirty-one subjects out of forty subjects completed the search training study which included a pre-test, a six-day’s training of Internet search, and a post-test. During the pre- and post- tests, subjects were asked to search online the answers to 40 unusual questions, remember the answers and recall them in the scanner. Un-learned questions were randomly presented at the recalling stage in order to elicited search impulse. Comparing to the pre-test, subjects in the post-test reported higher impulse to use search engines to answer un-learned questions. Consistently, subjects showed higher brain activations in dorsolateral prefrontal cortex and anterior cingulate cortex in the post-test than in the pre-test. In addition, there were significant positive correlations self-reported search impulse and brain responses in the frontal areas. The results suggest that a simple six-day’s Internet search training can make people dependent on the search tools when facing unknown issues. People are easily dependent on the Internet search engines. PMID:28441408

The Prospective Joint Effects of Self-Regulation and Impulsive Processes on Early Adolescence Alcohol Use

PubMed Central

O’Connor, Roisin M.; Colder, Craig R.

2015-01-01

Objective: Dual-process models propose that behavior is influenced by the interactive effect of impulsive (automatic) and selfregulatory (controlled) processes. Elaborations of this model posit that the effect of impulsive processes on alcohol use is influenced by capacity and motivation to self-regulate. The interactive effect of these three processes on drinking has not previously been tested. The goal of this study was to provide a developmental extension of this model to early adolescent alcohol use and to test the three-way interaction between impulsive processes (implicit alcohol cognition), self-regulatory capacity (inhibitory and activation control), and self-regulatory motivation (negative alcohol outcome expectancies [AOE]) in a 1-year prospective prediction of adolescent alcohol use. Method: Adolescents (N = 325; 54% girls, mean age = 13.6 years at baseline) completed the Single Category Implicit Association Test and self-reports of alcohol expectancies and use. Inhibitory and activation control were based on parental report. Results: Negative AOE and inhibitory/activation control were supported as moderators of the effect of implicit alcohol cognition on 1-year prospective alcohol use. As expected, weak implicit negative alcohol cognition was associated with elevated alcohol use when both negative AOE and inhibitory control were low. Contrary to hypothesis, when activation control was high, weak implicit negative alcohol cognition was unrelated to alcohol use if negative AOE were high (p = .72) (vs. low, p < .01).Activation control may reflect the ability to plan ahead and act pro-socially. Conclusions: Our study supports current theory suggesting alcohol use is influenced by a complex interplay of impulsive and self-regulatory processes. PMID:26562596

Cognitive and behavioural dispositions in offspring at high risk for alcoholism.

PubMed

Kumar, Rajesh; Kumar, Keshav Janakiprasad; Benegal, Vivek

2018-06-01

Offspring with family history of alcoholism are considered to be at high risk for alcoholism. The present study sought to expand our understanding of cognitive and behavioural dispositions associated with executive control and self-regulation in alcohol naïve offspring with and without family history of alcoholism. Sample comprised of alcohol naive offspring in two groups: (i) at high risk (n = 34) and (ii) at low risk for alcoholism (n = 34). Both groups were matched on age (+/-1 year), education (+/-1 year) and gender. Measures used were: Mini-International Neuropsychiatric Interview, Family Interview for Genetic Studies, Socio-demographic Data Sheet, Annett's Handedness Questionnaire, Barratt's Impulsiveness Scale-version 11, Digit Span Test, Spatial Span Test, Tower of London, Wisconsin Card Sorting Test, Iowa Gambling Task (IGT) and Game of Dice Task (GDT). Results showed that alcohol naive offspring at high risk for alcoholism reported significantly high impulsivity and demonstrated significant differences on executive functions and decision making tasks. Correlation analysis revealed that high impulsivity was significantly associated with poor performance on explicit decision making task (GDT) and executive function task (WCST). There was no significant correlation between two decision making tasks (IGT and GDT) in both groups and performance on IGT was not significantly associated with impulsivity and executive functions. The present study indicates cognitive and behavioural dispositions in alcohol naive offspring at high risk for alcoholism and support the sub-optimal balance between reflective and impulsive system responsible for addiction. Furthermore, present study supports separability between two different types of decision making tasks. Copyright © 2018 Elsevier B.V. All rights reserved.

Temperament and impulsivity predictors of smoking cessation outcomes.

PubMed

López-Torrecillas, Francisca; Perales, José C; Nieto-Ruiz, Ana; Verdejo-García, Antonio

2014-01-01

Temperament and impulsivity are powerful predictors of addiction treatment outcomes. However, a comprehensive assessment of these features has not been examined in relation to smoking cessation outcomes. Naturalistic prospective study. Treatment-seeking smokers (n = 140) were recruited as they engaged in an occupational health clinic providing smoking cessation treatment between 2009 and 2013. Participants were assessed at baseline with measures of temperament (Temperament and Character Inventory), trait impulsivity (Barratt Impulsivity Scale), and cognitive impulsivity (Go/No Go, Delay Discounting and Iowa Gambling Task). The outcome measure was treatment status, coded as "dropout" versus "relapse" versus "abstinence" at 3, 6, and 12 months endpoints. Participants were telephonically contacted and reminded of follow-up face to face assessments at each endpoint. The participants that failed to answer the phone calls or self-reported discontinuation of treatment and failed to attend the upcoming follow-up session were coded as dropouts. The participants that self-reported continuing treatment, and successfully attended the upcoming follow-up session were coded as either "relapse" or "abstinence", based on the results of smoking behavior self-reports cross-validated with co-oximetry hemoglobin levels. Multinomial regression models were conducted to test whether temperament and impulsivity measures predicted dropout and relapse relative to abstinence outcomes. Higher scores on temperament dimensions of novelty seeking and reward dependence predicted poorer retention across endpoints, whereas only higher scores on persistence predicted greater relapse. Higher scores on the trait dimension of non-planning impulsivity but not performance on cognitive impulsivity predicted poorer retention. Higher non-planning impulsivity and poorer performance in the Iowa Gambling Task predicted greater relapse at 3 and 6 months and 6 months respectively. Temperament measures, and specifically novelty seeking and reward dependence, predict smoking cessation treatment retention, whereas persistence, non-planning impulsivity and poor decision-making predict smoking relapse.

Deletion of alpha-synuclein decreases impulsivity in mice.

PubMed

Peña-Oliver, Y; Buchman, V L; Dalley, J W; Robbins, T W; Schumann, G; Ripley, T L; King, S L; Stephens, D N

2012-03-01

The presynaptic protein alpha-synuclein, associated with Parkinson's Disease (PD), plays a role in dopaminergic neurotransmission and is implicated in impulse control disorders (ICDs) such as drug addiction. In this study we investigated a potential causal relationship between alpha-synuclein and impulsivity, by evaluating differences in motor impulsivity in the 5-choice serial reaction time task (5-CSRTT) in strains of mice that differ in the expression of the alpha-synuclein gene. C57BL/6JOlaHsd mice differ from their C57BL/6J ancestors in possessing a chromosomal deletion resulting in the loss of two genes, snca, encoding alpha-synuclein, and mmrn1, encoding multimerin-1. C57BL/6J mice displayed higher impulsivity (more premature responding) than C57BL/6JOlaHsd mice when the pre-stimulus waiting interval was increased in the 5-CSRTT. In order to ensure that the reduced impulsivity was indeed related to snca, and not adjacent gene deletion, wild type (WT) and mice with targeted deletion of alpha-synuclein (KO) were tested in the 5-CSRTT. Similarly, WT mice were more impulsive than mice with targeted deletion of alpha-synuclein. Interrogation of our ongoing analysis of impulsivity in BXD recombinant inbred mouse lines revealed an association of impulsive responding with levels of alpha-synuclein expression in hippocampus. Expression of beta- and gamma-synuclein, members of the synuclein family that may substitute for alpha-synuclein following its deletion, revealed no differential compensations among the mouse strains. These findings suggest that alpha-synuclein may contribute to impulsivity and potentially, to ICDs which arise in some PD patients treated with dopaminergic medication. © 2011 The Authors. Genes, Brain and Behavior © 2011 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.

Ethanol induces impulsive-like responding in a delay-of-reward operant choice procedure: impulsivity predicts autoshaping.

PubMed

Tomie, A; Aguado, A S; Pohorecky, L A; Benjamin, D

1998-10-01

Autoshaping conditioned responses (CRs) are reflexive and targeted motor responses expressed as a result of experience with reward. To evaluate the hypothesis that autoshaping may be a form of impulsive responding, within-subjects correlations between performance on autoshaping and impulsivity tasks were assessed in 15 Long-Evans hooded rats. Autoshaping procedures [insertion of retractable lever conditioned stimulus (CS) followed by the response-independent delivery of food (US)] were followed by testing for impulsive-like responding in a two-choice lever-press operant delay-of-reward procedure (immediate small food reward versus delayed large food reward). Delay-of-reward functions revealed two distinct subject populations. Subjects in the Sensitive group (n=7) were more impulsive-like, increasing immediate reward choices at longer delays for large reward, while those in the Insensitive group (n=8) responded predominantly on only one lever. During the prior autoshaping phase, the Sensitive group had performed more autoshaping CRs, and correlations revealed that impulsive subjects acquired the autoshaping CR in fewer trials. In the Sensitive group, acute injections of ethanol (0, 0.25, 0.50, 1.00, 1.50 g/kg) given immediately before delay-of-reward sessions yielded an inverted U-shaped dose-response curve with increased impulsivity induced by the 0.25, 0.50, and 1.00 g/kg doses of ethanol, while choice strategy of the Insensitive group was not influenced by ethanol dose. Ethanol induced impulsive-like responding only in rats that were flexible in their response strategy (Sensitive group), and this group also performed more autoshaping CRs. Data support the hypothesis that autoshaping and impulsivity are linked.

Lesions to the subthalamic nucleus decrease impulsive choice but impair autoshaping in rats: the importance of the basal ganglia in Pavlovian conditioning and impulse control.

PubMed

Winstanley, Catharine A; Baunez, Christelle; Theobald, David E H; Robbins, Trevor W

2005-06-01

Although the subthalamic nucleus (STN) is involved in regulating motor function, and inactivation of this structure relieves the motor symptoms in Parkinsonian patients, recent data indicate that corticosubthalamic connections are involved in both the regulation of attention and the ability to withhold from responding. Considerable evidence suggests that the neural circuitry underlying such behavioural disinhibition or impulsive action can be at least partially dissociated from that implicated in impulsive decision-making and it has been suggested that the tendency to choose impulsively is related to the ability to form and use Pavlovian associations. To explore these hypotheses further, STN-lesioned rats were tested on the delay-discounting model of impulsive choice, where impulsivity is defined as the selection of a small immediate over a larger delayed reward, as well as in a rodent autoshaping paradigm. In contrast to previous reports of increased impulsive action, STN lesions decreased impulsive choice but dramatically impaired the acquisition of the autoshaping response. When the STN was lesioned after the establishment of autoshaping behaviour, lesioned subjects were more sensitive to the omission of reward, indicative of a reduction in the use of Pavlovian associations to control autoshaping performance. These results emphasize the importance of the STN in permitting conditioned stimulus-unconditioned stimulus associations to regulate goal-seeking, a function which may relate to the alterations in impulsive choice observed in the delay-discounting task. These data bear a striking similarity to those observed after lesions of the orbitofrontal cortex and are suggestive of an important role for corticosubthalamic connections in complex cognitive behaviour.

[Air conducted ocular VEMP: II. First clinical investigations].

PubMed

Walther, L E; Schaaf, H; Sommer, D; Hörmann, K

2011-10-01

Vestibular-evoked myogenic potentials (VEMP) are widely used to assess vestibular function. Air conducted (AC) cervical VEMP (cVEMP) reflect sacculus and inferior vestibular nerve function. Ocular VEMP (oVEMP) however has been hardly examined up to now. In recent studies it has been assumed that AC oVEMP probably reflects superior vestibular nerve function. The aim of this pilot study was to evaluate clinical application of the AC oVEMP. AC oVEMP were recorded in patients with peripheral vestibular disorders (n=21). In addition thermal irritation and head impulse test were performed and AC cVEMP were recorded. For intense AC-sound stimulation tone bursts (500 Hz) with 100 dB nHL were used. In peripheral vestibular disorders AC oVEMP and AC cVEMP could be classified into: • type 1 (inferior vestibular neuritis) with loss of AC oVEMP but normal AC cVEMP, • type 2, probable type of superior vestibular neuritis, showing present AC cVEMP but loss of AC oVEMP, • type 3, probable complete vestibular neuritis, without AC oVEMP and AC cVEMP. AC oVEMP may be used as an appropriate test for clinical investigation in patients with vestibular disorders. AC oVEMP is an additional, essential test for assessing otolith function beside AC cVEMP. Further vestibular test are necessary for precise clinical interpretation. © Georg Thieme Verlag KG Stuttgart · New York.

A neuroscientific approach to the examination of concussions in student-athletes.

PubMed

Ketcham, Caroline J; Hall, Eric; Bixby, Walter R; Vallabhajosula, Srikant; Folger, Stephen E; Kostek, Matthew C; Miller, Paul C; Barnes, Kenneth P; Patel, Kirtida

2014-12-08

Concussions are occurring at alarming rates in the United States and have become a serious public health concern. The CDC estimates that 1.6 to 3.8 million concussions occur in sports and recreational activities annually. Concussion as defined by the 2013 Concussion Consensus Statement "may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an 'impulsive' force transmitted to the head." Concussions leave the individual with both short- and long-term effects. The short-term effects of sport related concussions may include changes in playing ability, confusion, memory disturbance, the loss of consciousness, slowing of reaction time, loss of coordination, headaches, dizziness, vomiting, changes in sleep patterns and mood changes. These symptoms typically resolve in a matter of days. However, while some individuals recover from a single concussion rather quickly, many experience lingering effects that can last for weeks or months. The factors related to concussion susceptibility and the subsequent recovery times are not well known or understood at this time. Several factors have been suggested and they include the individual's concussion history, the severity of the initial injury, history of migraines, history of learning disabilities, history of psychiatric comorbidities, and possibly, genetic factors. Many studies have individually investigated certain factors both the short-term and long-term effects of concussions, recovery time course, susceptibility and recovery. What has not been clearly established is an effective multifaceted approach to concussion evaluation that would yield valuable information related to the etiology, functional changes, and recovery. The purpose of this manuscript is to show one such multifaceted approached which examines concussions using computerized neurocognitive testing, event related potentials, somatosensory perceptual responses, balance assessment, gait assessment and genetic testing.

Interaction between Family History of Alcoholism and Locus of Control in the Opioid Regulation of Impulsive Responding under the Influence of Alcohol

PubMed Central

Altamirano, Lee J.; Fields, Howard L.; D’Esposito, Mark; Boettiger, Charlotte A.

2011-01-01

Background Naltrexone (NTX) is an opioid antagonist indicated for the treatment of alcoholism, which is not universally effective. Thus, identifying individual predictors of NTX’s behavioral effects is critical to optimizing its therapeutic use. Moreover, given the high rate of relapse during treatment for alcoholism, understanding NTX’s behavioral effects when combined with moderate ethanol intake is important. Our previous study of abstinent alcoholics and control subjects showed that a more internal Locus of Control score predicted increased impulsive choice on NTX (Mitchell et al., 2007). Here we tested whether this predictive relationship remains in the context of moderate alcohol intake. Methods In the present study we tested the effect of acute NTX (50mg) on impulsive choice, motor inhibition, and attentional bias after ingestion of moderate ethanol (~0.3g/kg, n = 30 subjects). Subjects included those recruited from a pool of ~1200 UC Berkeley undergraduates on the basis of scores on the Barratt Impulsiveness Scale (BIS). Results Impulsive choice was positively correlated with breath alcohol concentration in placebo sessions. Locus of Control was again the sole predictor of NTX’s effect on decision-making among subjects with a family history of alcoholism. We also found a weak interaction between BIS scores and NTX’s effect on impulsive choice. Conclusions Our results reinforce the predictive relationship between Locus of Control and NTX’s effect on decision-making in those with a family history of alcoholism, suggesting a possible biological basis to this relationship. PMID:21569055

Mindful eating reduces impulsive food choice in adolescents and adults.

PubMed

Hendrickson, Kelsie L; Rasmussen, Erin B

2017-03-01

The present study tested the extent to which age and obesity predicted impulsive choices for food and monetary outcomes and tested how a brief mindful-eating training would alter delay discounting for food and money choices compared with control groups. First, 172 adolescents (M age = 13.13 years) and 176 (M age = 23.33 years) adults completed the Food Choice Questionnaire (FCQ) and Monetary Choice Questionnaire (MCQ) as measures of food and money delay discounting, respectively. Then, participants returned to the lab and were randomly assigned to complete a brief mindful-eating training, watch a DVD on nutrition, or serve as a control. Participants completed the FCQ and MCQ again as a postmanipulation measure. Participants with high percent body fat (PBF) were more impulsive for food than those with low PBF. Adults with high PBF were also more impulsive for money compared with adults with low PBF; no PBF-related differences were found for adolescents. Participants in the mindful-eating group exhibited more self-controlled choices for food, but not for money. The control conditions did not exhibit changes. The study suggests that individuals with high PBF make more impulsive food choices relative to those with low PBF, which could increase the risk of obesity over time. It also is the first to demonstrate shifts in choice patterns for food and money using a brief mindful-eating training with adolescents. Mindful eating is a beneficial strategy to reduce impulsive food choice, at least temporarily, that may impede weight gain. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Dissociable effects of cocaine and yohimbine on impulsive action and relapse to cocaine seeking.

PubMed

Broos, Nienke; van Mourik, Yvar; Schetters, Dustin; De Vries, Taco J; Pattij, Tommy

2017-11-01

A strong association has been demonstrated between various forms of impulsivity and addiction-like behavior in both humans and rats. In this study, we investigated how impulsive action, as measured in the 5-choice serial reaction time task (5-CSRTT), is affected during various stages of cocaine taking and seeking and by relapse-provoking stimuli in animals that were trained both in an intravenous cocaine self-administration paradigm and in the 5-CSRTT. Rats were concurrently trained in the 5-CSRTT and cocaine self-administration protocol, and subsequently, the effects of cocaine (7.5 mg/kg) and the pharmacological stressor yohimbine (1.25 mg/kg) were tested in both paradigms. Cocaine self-administration (5 h/day) transiently altered impulsive action and increased errors of omission in the 5-CSRTT. Pharmacological challenges with cocaine and yohimbine induced increments in impulsive action and reinstated cocaine-seeking responses within the same animals. Further analyses revealed that the effects of cocaine and yohimbine on impulsive action did not correlate with their effects on reinstatement of cocaine seeking. These data suggest that although impulsive action and relapse can be pharmacologically modulated in the same direction within individuals, these effects appear not to be directly coupled.

Bidirectional-Compounding Effects of Rumination and Negative Emotion in Predicting Impulsive Behavior: Implications for Emotional Cascades.

PubMed

Selby, Edward A; Kranzler, Amy; Panza, Emily; Fehling, Kara B

2016-04-01

Influenced by chaos theory, the emotional cascade model proposes that rumination and negative emotion may promote each other in a self-amplifying cycle that increases over time. Accordingly, exponential-compounding effects may better describe the relationship between rumination and negative emotion when they occur in impulsive persons, and predict impulsive behavior. Forty-seven community and undergraduate participants who reported frequent engagement in impulsive behaviors monitored their ruminative thoughts and negative emotion multiple times daily for two weeks using digital recording devices. Hypotheses were tested using cross-lagged mixed model analyses. Findings indicated that rumination predicted subsequent elevations in rumination that lasted over extended periods of time. Rumination and negative emotion predicted increased levels of each other at subsequent assessments, and exponential functions for these associations were supported. Results also supported a synergistic effect between rumination and negative emotion, predicting larger elevations in subsequent rumination and negative emotion than when one variable alone was elevated. Finally, there were synergistic effects of rumination and negative emotion in predicting number of impulsive behaviors subsequently reported. These findings are consistent with the emotional cascade model in suggesting that momentary rumination and negative emotion progressively propagate and magnify each other over time in impulsive people, promoting impulsive behavior. © 2014 Wiley Periodicals, Inc.

Amygdala reactivity to fearful faces correlates positively with impulsive aggression.

PubMed

da Cunha-Bang, Sofi; Fisher, Patrick M; Hjordt, Liv V; Holst, Klaus; Knudsen, Gitte M

2018-01-07

Facial expressions robustly activate the amygdala, a brain structure playing a critical role in aggression. Whereas previous studies suggest that amygdala reactivity is related to various measures of impulsive aggression, we here estimate a composite measure of impulsive aggression and evaluate whether it is associated with amygdala reactivity to angry and fearful faces. We estimated amygdala reactivity with functional magnetic resonance imaging in 47 men with varying degree of aggressive traits (19 incarcerated violent offenders and 28 healthy controls). We modeled a composite "impulsive aggression" trait construct (LV agg ) using a linear structural equation model, with a single latent variable capturing the shared correlation between five self-report measures of trait aggression, anger and impulsivity. We tested for associations between amygdala reactivity and the LV agg , adjusting for age and group. The LV agg was significantly positively associated with amygdala reactivity to fearful (p = 0.001), but not angry faces (p = 0.9). We found no group difference in amygdala reactivity to fearful or angry faces. The findings suggest that that amygdala reactivity to fearful faces is represented by a composite index of impulsive aggression and provide evidence that impulsive aggression is associated with amygdala reactivity in response to submissive cues, i.e., fearful faces.

Depression in university students: associations with impulse control disorders.

PubMed

Leppink, Eric W; Lust, Katherine; Grant, Jon E

2016-09-01

The purpose of this study was to assess the implications of depression in a sample of university students, particularly relating to impulse control disorders. While previous studies have shown high rates of depression among university students, no study to date has assessed whether levels of depression show associations with the incidence of impulse control disorders in this population. In all, 6000 students participated in the College Student Computer Use Survey. A total of 1717 students completed the scales of interest for this analysis. Participants were assigned to groups based on depression scores: severe (N = 75), mild/moderate (N = 647) and none (N = 995). The three groups were assessed using analysis of variance (ANOVA) or chi-square test. A multinomial logistic regression analysis was used to elucidate associations between depression and impulse control disorder diagnoses. Groups differed across demographic, health and academic variables. The severe depression group reported higher rates of skin-picking disorder, compulsive sexual behaviour and compulsive buying. Results suggest a significant association between depression and impulse control disorders. One possibility is that a facet of impulsivity contributes to both problems, which could be important information for clinicians. Future studies will need to clarify the exact nature of the relationship between depression and impulse control disorders.

Impulse control disorders in Parkinson's disease: decreased striatal dopamine transporter levels.

PubMed

Voon, Valerie; Rizos, Alexandra; Chakravartty, Riddhika; Mulholland, Nicola; Robinson, Stephanie; Howell, Nicholas A; Harrison, Neil; Vivian, Gill; Ray Chaudhuri, K

2014-02-01

Impulse control disorders are commonly associated with dopaminergic therapy in Parkinson's disease (PD). PD patients with impulse control disorders demonstrate enhanced dopamine release to conditioned cues and a gambling task on [(11)C]raclopride positron emission tomography (PET) imaging and enhanced ventral striatal activity to reward on functional MRI. We compared PD patients with impulse control disorders and age-matched and gender-matched controls without impulse control disorders using [(123)I]FP-CIT (2β-carbomethoxy-3β-(4-iodophenyl)tropane) single photon emission computed tomography (SPECT), to assess striatal dopamine transporter (DAT) density. The [(123)I]FP-CIT binding data in the striatum were compared between 15 PD patients with and 15 without impulse control disorders using independent t tests. Those with impulse control disorders showed significantly lower DAT binding in the right striatum with a trend in the left (right: F(1,24)=5.93, p=0.02; left: F(1,24)=3.75, p=0.07) compared to controls. Our findings suggest that greater dopaminergic striatal activity in PD patients with impulse control disorders may be partly related to decreased uptake and clearance of dopamine from the synaptic cleft. Whether these findings are related to state or trait effects is not known. These findings dovetail with reports of lower DAT levels secondary to the effects of methamphetamine and alcohol. Although any regulation of DAT by antiparkinsonian medication appears to be modest, PD patients with impulse control disorders may be differentially sensitive to regulatory mechanisms of DAT expression by dopaminergic medications.

Reflection impulsivity in binge drinking: behavioural and volumetric correlates

PubMed Central

Banca, Paula; Lange, Iris; Worbe, Yulia; Howell, Nicholas A.; Irvine, Michael; Harrison, Neil A.; Moutoussis, Michael

2015-01-01

Abstract The degree to which an individual accumulates evidence prior to making a decision, also known as reflection impulsivity, can be affected in psychiatric disorders. Here, we study decisional impulsivity in binge drinkers, a group at elevated risk for developing alcohol use disorders, comparing two tasks assessing reflection impulsivity and a delay discounting task, hypothesizing impairments in both subtypes of impulsivity. We also assess volumetric correlates of reflection impulsivity focusing on regions previously implicated in functional magnetic resonance imaging studies. Sixty binge drinkers and healthy volunteers were tested using two different information‐gathering paradigms: the beads task and the Information Sampling Task (IST). The beads task was analysed using a behavioural approach and a Bayesian model of decision making. Delay discounting was assessed using the Monetary Choice Questionnaire. Regression analyses of primary outcomes were conducted with voxel‐based morphometry analyses. Binge drinkers sought less evidence prior to decision in the beads task compared with healthy volunteers in both the behavioural and computational modelling analysis. There were no group differences in the IST or delay discounting task. Greater impulsivity as indexed by lower evidence accumulation in the beads task was associated with smaller dorsolateral prefrontal cortex and inferior parietal volumes. In contrast, greater impulsivity as indexed by lower evidence accumulation in the IST was associated with greater dorsal cingulate and precuneus volumes. Binge drinking is characterized by impaired reflection impulsivity suggesting a deficit in deciding on the basis of future outcomes that are more difficult to represent. These findings emphasize the role of possible therapeutic interventions targeting decision‐making deficits. PMID:25678093

Impulse control disorders in Parkinson's disease: decreased striatal dopamine transporter levels

PubMed Central

Voon, Valerie; Rizos, Alexandra; Chakravartty, Riddhika; Mulholland, Nicola; Robinson, Stephanie; Howell, Nicholas A; Harrison, Neil; Vivian, Gill; Ray Chaudhuri, K

2014-01-01

Objective Impulse control disorders are commonly associated with dopaminergic therapy in Parkinson's disease (PD). PD patients with impulse control disorders demonstrate enhanced dopamine release to conditioned cues and a gambling task on [11C]raclopride positron emission tomography (PET) imaging and enhanced ventral striatal activity to reward on functional MRI. We compared PD patients with impulse control disorders and age-matched and gender-matched controls without impulse control disorders using [123I]FP-CIT (2β-carbomethoxy-3β-(4-iodophenyl)tropane) single photon emission computed tomography (SPECT), to assess striatal dopamine transporter (DAT) density. Methods The [123I]FP-CIT binding data in the striatum were compared between 15 PD patients with and 15 without impulse control disorders using independent t tests. Results Those with impulse control disorders showed significantly lower DAT binding in the right striatum with a trend in the left (right: F(1,24)=5.93, p=0.02; left: F(1,24)=3.75, p=0.07) compared to controls. Conclusions Our findings suggest that greater dopaminergic striatal activity in PD patients with impulse control disorders may be partly related to decreased uptake and clearance of dopamine from the synaptic cleft. Whether these findings are related to state or trait effects is not known. These findings dovetail with reports of lower DAT levels secondary to the effects of methamphetamine and alcohol. Although any regulation of DAT by antiparkinsonian medication appears to be modest, PD patients with impulse control disorders may be differentially sensitive to regulatory mechanisms of DAT expression by dopaminergic medications. PMID:23899625

Attention impairment in childhood absence epilepsy: an impulsivity problem?

PubMed

Cerminara, Caterina; D'Agati, Elisa; Casarelli, Livia; Kaunzinger, Ivo; Lange, Klaus W; Pitzianti, Mariabernarda; Parisi, Pasquale; Tucha, Oliver; Curatolo, Paolo

2013-05-01

Although attention problems have often been described in children with childhood absence epilepsy (CAE), the use of different methodological approaches, neuropsychological tests, and heterogeneous experimental groups has prevented identification of the selective areas of attention deficit in this population. In this study, we investigated several components of attention in children with CAE using a unique computerized test battery for attention performance. Participants included 24 patients with CAE and 24 controls matched for age and sex. They were tested with a computerized test battery, which included the following tasks: selective attention, impulsivity, focused attention, divided attention, alertness, and vigilance. Compared with healthy controls, patients with CAE made more commission errors in the Go/No-Go task and more omission errors in the divided attention task. Childhood absence epilepsy patients also showed decreased reaction times in measures of selective attention and a great variability of reaction times in alertness and Go/No-Go tasks. Our findings suggest that patients with CAE were impaired in tonic and phasic alertness, divided attention, selective attention, and impulsivity. Copyright © 2013 Elsevier Inc. All rights reserved.

Metacognitive ability of male students: difference impulsive-reflective cognitive style

NASA Astrophysics Data System (ADS)

Muhtarom; Sugiyanti; Utami, R. E.; Indriana, K.

2018-03-01

This study revealed the metacognitive activity of male students in impulsive cognitive and reflective cognitive style in solving mathematical problems, especially in the material of plane. One student of impulsive cognitive style and one student of reflective cognitive-style were selected to be the subjects of the study. Data were collected by giving written test of problem solving and interview. Data analysis was done through data reduction, data presentation, data interpretation and conclusion. The results showed that male student of reflective cognitive style was meticulous and careful in solving the problem so as to obtain correct answers, while the impulsive cognitive style student had the characteristics of using a short time in solving the problem, but less careful so that the answers tended to be wrong

Numerical Simulations of Near-Field Blast Effects using Kinetic Plates

NASA Astrophysics Data System (ADS)

Neuscamman, Stephanie; Manner, Virginia; Brown, Geoffrey; Glascoe, Lee

2013-06-01

Numerical simulations using two hydrocodes were compared to near-field measurements of blast impulse associated with ideal and non-ideal explosives to gain insight into testing results and predict untested configurations. The recently developed kinetic plate test was designed to measure blast impulse in the near-field by firing spherical charges in close range from steel plates and probing plate acceleration using laser velocimetry. Plate velocities for ideal, non-ideal and aluminized explosives tests were modeled using a three dimensional hydrocode. The effects of inert additives in the explosive formulation were modeled using a 1-D hydrocode with multiphase flow capability using Lagrangian particles. The relative effect of particle impact on the plate compared to the blast wave impulse is determined and modeling is compared to free field pressure results. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This is abstract LLNL-ABS-622152.

The Effect of Citicoline Supplementation on Motor Speed and Attention in Adolescent Males.

PubMed

McGlade, Erin; Agoston, Anna Monica; DiMuzio, Jennifer; Kizaki, Miho; Nakazaki, Eri; Kamiya, Toshikazu; Yurgelun-Todd, Deborah

2015-07-15

This study assessed the effects of citicoline, a nutraceutical, on attention, psychomotor function, and impulsivity in healthy adolescent males. Seventy-five healthy adolescent males were randomly assigned to either the citicoline group (n = 51 with 250 or 500 mg citicoline) or placebo (n = 24). Participants completed the Ruff 2&7 Selective Attention Test, Finger Tap Test, and the Computerized Performance Test, Second Edition (CPT-II) at baseline and after 28 days of supplementation. Individuals receiving citicoline exhibited improved attention (p = 0.02) and increased psychomotor speed (p = 0.03) compared with those receiving placebo. Higher weight-adjusted dose significantly predicted increased accuracy on an attention task (p = 0.01), improved signal detectability on a computerized attention task (p = 0.03), and decreased impulsivity (p = 0.01). Adolescent males receiving 28 days of Cognizin® citicoline showed improved attention and psychomotor speed and reduced impulsivity compared to adolescent males who received placebo. © 2015 SAGE Publications.

Heading Frequency Is More Strongly Related to Cognitive Performance Than Unintentional Head Impacts in Amateur Soccer Players.

PubMed

Stewart, Walter F; Kim, Namhee; Ifrah, Chloe; Sliwinski, Martin; Zimmerman, Molly E; Kim, Mimi; Lipton, Richard B; Lipton, Michael L

2018-01-01

Compared to heading, unintentional head impacts (e.g., elbow to head, head to head, head to goalpost) in soccer are more strongly related to risk of moderate to very severe Central Nervous System (CNS) symptoms. But, most head impacts associated with CNS symptoms that occur in soccer are mild and are more strongly related to heading. We tested for a differential relation of heading and unintentional head impacts with neuropsychological (NP) test performance. Active adult amateur soccer players were recruited in New York City and the surrounding areas for this repeated measures longitudinal study of individuals who were enrolled if they had 5+ years of soccer play and were active playing soccer 6+ months/year. All participants completed a baseline validated questionnaire ("HeadCount-2w"), reporting 2-week recall of soccer activity, heading and unintentional head impacts. In addition, participants also completed NP tests of verbal learning, verbal memory, psychomotor speed, attention, and working memory. Most participants also completed one or more identical follow-up protocols (i.e., HeadCount-2w and NP tests) at 3- to 6-month intervals over a 2-year period. Repeated measures General Estimating Equations (GEE) linear models were used to determine if variation in NP tests at each visit was related to variation in either heading or unintentional head impacts in the 2-week period before testing. 308 players (78% male) completed 741 HeadCount-2w. Mean (median) heading/2-weeks was 50 (17) for men and 26 (7) for women. Heading was significantly associated with poorer performance on psychomotor speed ( p  < 0.001) and attention ( p  = 0.02) tasks and was borderline significant with poorer performance on the working memory ( p  = 0.06) task. Unintentional head impacts were not significantly associated with any NP test. Results did not differ after excluding 22 HeadCount-2w with reported concussive or borderline concussive symptoms. Poorer NP test performance was consistently related to frequent heading during soccer practice and competition in the 2 weeks before testing. In contrast, unintentional head impacts incurred during soccer were not related to cognitive performance.

49 CFR 572.122 - Head assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 7 2011-10-01 2011-10-01 false Head assembly and test procedure. 572.122 Section...-year-old Child Test Dummy, Beta Version § 572.122 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 127-1000), a six-axis neck transducer...

49 CFR 572.122 - Head assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Head assembly and test procedure. 572.122 Section...-year-old Child Test Dummy, Beta Version § 572.122 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 127-1000), a six-axis neck transducer...

49 CFR 572.122 - Head assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Head assembly and test procedure. 572.122 Section...-year-old Child Test Dummy, Beta Version § 572.122 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 127-1000), a six-axis neck transducer...

49 CFR 572.122 - Head assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Head assembly and test procedure. 572.122 Section...-year-old Child Test Dummy, Beta Version § 572.122 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 127-1000), a six-axis neck transducer...

Implementation and extension of the impulse transfer function method for future application to the space shuttle project. Volume 1: Analysis and correlation studies

NASA Technical Reports Server (NTRS)

Mantus, M.; Pardo, H.

1973-01-01

Computer programming, data processing, and a correlation study that employed data collected in the first phase test were used to demonstrate that standard test procedures and equipment could be used to collect a significant number of transfer functions from tests of the Lunar Module test article LTA-11. The testing consisted of suspending the vehicle from the apex fittings of the outrigger trusses through a set of air springs to simulate the free-free state. Impulsive loadings were delivered, one at a time, at each of the landing gear's attachment points, in three mutually perpendicular directions; thus a total of 36 impulses were applied to the vehicle. Time histories of each pulse were recorded on magnetic tape along with 40 channels of strain gage response and 28 channels of accelerometer response. Since an automated data processing system was not available, oscillograph playbacks were made of all 2400 time histories as a check on the validity of the data taken. In addition, one channel of instrumentation was processed to determine its response to a set of forcing functions from a prior LTA-11 drop test. This prediction was compared with drop test results as a first measure of accuracy.

Evaluation of the King-Devick test as a concussion screening tool in high school football players.

PubMed

Seidman, Daniel H; Burlingame, Jennifer; Yousif, Lina R; Donahue, Xinh P; Krier, Joshua; Rayes, Lydia J; Young, Rachel; Lilla, Muareen; Mazurek, Rochelle; Hittle, Kristie; McCloskey, Charles; Misra, Saroj; Shaw, Michael K

2015-09-15

Concussion is the most common type of traumatic brain injury, and results from impact or impulsive forces to the head, neck or face. Due to the variability and subtlety of symptoms, concussions may go unrecognized or be ignored, especially with the pressure placed on athletes to return to competition. The King-Devick (KD) test, an oculomotor test originally designed for reading evaluation, was recently validated as a concussion screening tool in collegiate athletes. A prospective study was performed using high school football players in an attempt to study the KD as a concussion screening tool in this younger population. 343 athletes from four local high school football teams were recruited to participate. These athletes were given baseline KD tests prior to competition. Individual demographic information was collected on the subjects. Standard team protocol was employed to determine if a concussion had occurred during competition. Immediately after diagnosis, the KD test was re-administered to the concussed athlete for comparison to baseline. Post-season testing was also performed in non-concussed individuals. Of the 343 athletes, nine were diagnosed with concussions. In all concussed players, cumulative read times for the KD test were significantly increased (p<0.001). Post-season testing of non-concussed athletes revealed minimal change in read times relative to baseline. Univariate analysis revealed that history of concussion was the only demographic factor predictive of concussion in this cohort. The KD test is an accurate and easily administered sideline screening tool for concussion in adolescent football players. Copyright © 2015 Elsevier B.V. All rights reserved.

The Influence of Using Momentum and Impulse Computer Simulation to Senior High School Students’ Concept Mastery

NASA Astrophysics Data System (ADS)

Kaniawati, I.; Samsudin, A.; Hasopa, Y.; Sutrisno, A. D.; Suhendi, E.

2016-08-01

This research is based on students’ lack of mastery of physics abstract concepts. Thus, this study aims to improve senior high school students’ mastery of momentum and impulse concepts with the use of computer simulation. To achieve these objectives, the research method employed was pre experimental design with one group pre-test post-test. A total of 36 science students of grade 11 in one of public senior high school in Bandung became the sample in this study. The instruments utilized to determine the increase of students’ concept mastery were pretest and posttest in the form of multiple choices. After using computer simulations in physics learning, students’ mastery of momentum and impulse concept has increased as indicated by the normalized gain of 0.64 with the medium category.

Single and Multi-Pulse Low-Energy Conical Theta Pinch Inductive Pulsed Plasma Thruster Performance

NASA Technical Reports Server (NTRS)

Hallock, A. K.; Martin, A. K.; Polzin, K. A.; Kimberlin, A. C.; Eskridge, R. H.

2013-01-01

Impulse bits produced by conical theta-pinch inductive pulsed plasma thrusters possessing cone angles of 20deg, 38deg, and 60deg, were quantified for 500J/pulse operation by direct measurement using a hanging-pendulum thrust stand. All three cone angles were tested in single-pulse mode, with the 38deg model producing the highest impulse bits at roughly 1 mN-s operating on both argon and xenon propellants. A capacitor charging system, assembled to support repetitively-pulsed thruster operation, permitted testing of the 38deg thruster at a repetition-rate of 5 Hz at power levels of 0.9, 1.6, and 2.5 kW. The average thrust measured during multiple-pulse operation exceeded the value obtained when the single-pulse impulse bit is multiplied by the repetition rate.

Milnacipran affects mouse impulsive, aggressive, and depressive-like behaviors in a distinct dose-dependent manner.

PubMed

Tsutsui-Kimura, Iku; Ohmura, Yu; Yoshida, Takayuki; Yoshioka, Mitsuhiro

2017-07-01

Serotonin/noradrenaline reuptake inhibitors (SNRIs) are widely used for the treatment for major depressive disorder, but these drugs induce several side effects including increased aggression and impulsivity, which are risk factors for substance abuse, criminal involvement, and suicide. To address this issue, milnacipran (0, 3, 10, or 30 mg/kg), an SNRI and antidepressant, was intraperitoneally administered to mice prior to the 3-choice serial reaction time task, resident-intruder test, and forced swimming test to measure impulsive, aggressive, and depressive-like behaviors, respectively. A milnacipran dose of 10 mg/kg suppressed all behaviors, which was accompanied by increased dopamine and serotonin levels in the medial prefrontal cortex (mPFC) but not in the nucleus accumbens (NAc). Although the most effective dose for depressive-like behavior was 30 mg/kg, the highest dose increased aggressive behavior and unaffected impulsive behavior. Increased dopamine levels in the NAc could be responsible for the effects. In addition, the mice basal impulsivity was negatively correlated with the latency to the first agonistic behavior. Thus, the optimal dose range of milnacipran is narrower than previously thought. Finding drugs that increase serotonin and dopamine levels in the mPFC without affecting dopamine levels in the NAc is a potential strategy for developing novel antidepressants. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Differentiating risk for mania and borderline personality disorder: The nature of goal regulation and impulsivity.

PubMed

Fulford, Daniel; Eisner, Lori R; Johnson, Sheri L

2015-06-30

Researchers and clinicians have long noted the overlap among features and high comorbidity of bipolar disorder and borderline personality disorder. The shared features of impulsivity and labile mood in both disorders make them challenging to distinguish. We tested the hypothesis that variables related to goal dysregulation would be uniquely related to risk for mania, while emotion-relevant impulsivity would be related to risk for both disorders. We administered a broad range of measures related to goal regulation traits and impulsivity to 214 undergraduates. Findings confirmed that risk for mania, but not for borderline personality disorder, was related to higher sensitivity to reward and intense pursuit of goals. In contrast, borderline personality disorder symptoms related more strongly than did mania risk with threat sensitivity and with impulsivity in the context of negative affect. Results highlight potential differences and commonalities in mania risk versus borderline personality disorder risk. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Factor Structure of the PTSD Checklist for DSM-5: Relationships Among Symptom Clusters, Anger, and Impulsivity.

PubMed

Armour, Cherie; Contractor, Ateka; Shea, Tracie; Elhai, Jon D; Pietrzak, Robert H

2016-02-01

Scarce data are available regarding the dimensional structure of Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) posttraumatic stress disorder (PTSD) symptoms and how factors relate to external constructs. We evaluated six competing models of DSM-5 PTSD symptoms, including Anhedonia, Externalizing Behaviors, and Hybrid models, using confirmatory factor analyses in a sample of 412 trauma-exposed college students. We then examined whether PTSD symptom clusters were differentially related to measures of anger and impulsivity using Wald chi-square tests. The seven-factor Hybrid model was deemed optimal compared with the alternatives. All symptom clusters were associated with anger; the strongest association was between externalizing behaviors and anger (r = 0.54). All symptom clusters, except re-experiencing and avoidance, were associated with impulsivity, with the strongest association between externalizing behaviors and impulsivity (r = 0.49). A seven-factor Hybrid model provides superior fit to DSM-5 PTSD symptom data, with the externalizing behaviors factor being most strongly related to anger and impulsivity.

Early Huntington's Disease: Impulse Control Deficits but Correct Judgment Regarding Risky Situations.

PubMed

Galvez, Victor; Fernandez-Ruiz, Juan; Bayliss, Leo; Ochoa-Morales, Adriana; Hernandez-Castillo, Carlos R; Díaz, Rosalinda; Campos-Romo, Aurelio

2017-01-01

Huntington's disease (HD) patients show alterations in decision making tasks. However, it is still uncertain if these deficits are due to poor judgment regarding risky situations, or to impulse control deficits. To elucidate whether decision-making in patients is related to genuine risk behavior or to impulse control deficits. To test between these two alternative possibilities, we evaluated the performance of 19 prodromal HD patients and 19 matched healthy controls in the Cambridge Gambling Task (CGT). This task assesses decision-making while dissociating between genuine risk-taking behaviors (ascending condition) from impulsive behavior (descending condition). The results showed that patients and controls had the same performance during all trials in the ascending condition, reflecting a correct judgment regarding risky situations; however, during the descending condition, patients responded before the controls in all trials, making a significantly larger number of higher bets. Unlike the control group, they did not wait for more optimal subsequent options. These results suggest impulse control deficits in HD gene carriers, but unimpaired risk-taking judgment.

Genetic relations among procrastination, impulsivity, and goal-management ability: implications for the evolutionary origin of procrastination.

PubMed

Gustavson, Daniel E; Miyake, Akira; Hewitt, John K; Friedman, Naomi P

2014-06-01

Previous research has revealed a moderate and positive correlation between procrastination and impulsivity. However, little is known about why these two constructs are related. In the present study, we used behavior-genetics methodology to test three predictions derived from an evolutionary account that postulates that procrastination arose as a by-product of impulsivity: (a) Procrastination is heritable, (b) the two traits share considerable genetic variation, and (c) goal-management ability is an important component of this shared variation. These predictions were confirmed. First, both procrastination and impulsivity were moderately heritable (46% and 49%, respectively). Second, although the two traits were separable at the phenotypic level (r = .65), they were not separable at the genetic level (r genetic = 1.0). Finally, variation in goal-management ability accounted for much of this shared genetic variation. These results suggest that procrastination and impulsivity are linked primarily through genetic influences on the ability to use high-priority goals to effectively regulate actions. © The Author(s) 2014.

Genetic Relations Among Procrastination, Impulsivity, and Goal-Management Ability: Implications for the Evolutionary Origin of Procrastination

PubMed Central

Gustavson, Daniel E.; Miyake, Akira; Hewitt, John K.; Friedman, Naomi P.

2014-01-01

Previous research has revealed a moderate positive correlation between procrastination and impulsivity. However, little is known about why these two constructs are related. This study used behavioral genetic methodology to test three predictions derived from an evolutionary account that postulates that procrastination arose as a by-product of impulsivity (Steel, 2010): (a) Procrastination is heritable; (b) the two traits share considerable genetic variation; and (c) goal-management ability is an important component of this shared variation. These predictions were confirmed. First, both procrastination and impulsivity were moderately heritable (46% and 49%, respectively). Second, although the two traits were separable at the phenotypic level (r=.65), they were not separable at the genetic level (rg=1.0). Finally, variation in goal-management ability accounted for much of this shared genetic variation. These results suggest that procrastination and impulsivity are linked primarily through genetic influences on the ability to use their high-priority goals effectively to regulate their action. PMID:24705635

Effect of a Mindfulness Training Program on the Impulsivity and Aggression Levels of Adolescents with Behavioral Problems in the Classroom

PubMed Central

Franco, Clemente; Amutio, Alberto; López-González, Luís; Oriol, Xavier; Martínez-Taboada, Cristina

2016-01-01

Objective: The aim of the present study was to analyze the effects of a mindfulness training psycho-educative program on impulsivity and aggression levels in a sample of high school students. Methods: A randomized controlled trial with pre-test–post-test measurements was applied to an experimental group and a control group (waiting list). The Barratt Impulsivity Scale (BIS-11) Patton et al. (1995) and the Aggression Questionnaire (Buss and Perry, 1992) were used. Results: Statistical analyses showed a significant decrease in the levels of impulsivity and aggressiveness in the experimental group compared with the control group. These results have important implications for improving the level of academic engagement and self-efficacy of students and for reducing school failure. Conclusion: This is one of the first studies showing the effectiveness of mindfulness training at reducing impulsive and aggressive behaviors in the classroom. The efficacy of mindfulness-based programs is emphasized. PMID:27713709

Executive Cognitive Functions and Impulsivity as Correlates of Risk Taking and Problem Behavior in Preadolescents

ERIC Educational Resources Information Center

Romer, Daniel; Betancourt, Laura; Giannetta, Joan M.; Brodsky, Nancy L.; Farah, Martha; Hurt, Hallam

2009-01-01

Initiation of drug use and other risky behavior in preadolescence is associated with poor developmental outcomes. In this research, we examine models that ascribe the trajectory to (a) weak executive cognitive function (ECF), (b) early manifestation of externalizing problems, or (c) heightened levels of trait impulsivity. We test the explanatory…

Impulsive-Reflective Attitude, Behavioural Inhibition and Motor Skills: Are They Linked?

ERIC Educational Resources Information Center

Rosey, Florence; Keller, Jean; Golomer, Eveline

2010-01-01

The present study aims to examine whether the inhibitory processes and impulsive-cognitive style can influence the emergence of coordination level among 61 children aged 3 to 5 years. Luria's tapping tasks, Day-Night tasks, Hand-Candle tasks, Go-NoGo tasks and the Trail Making Tests of Reitan, all involving inhibitory processes, were conducted.…

Strategy Differences Between Reflective and Impulsive Children.

ERIC Educational Resources Information Center

Adams, Wayne V.

In an investigation of search strategies, it was predicted that reflective children would have developmentally more mature problem-solving strategies than impulsive children, and the presence of these strategies would be found in both 6- and 8-year-old subjects. From a sample given the Matching Familiar Figures Test, half of the 20 boys and 20…

Sustained Attention at Age 5 Predicts Attention-Related Problems at Age 9

ERIC Educational Resources Information Center

Martin, Anne; Razza, Rachel A.; Brooks-Gunn, Jeanne

2012-01-01

This study tested whether two aspects of sustained attention (focused attention and lack of impulsivity) measured at child age 5 predicted attention problems reported by mothers and teachers at age 9. Because lack of impulsivity reflects the executive control network, and ADHD is commonly characterized as a deficit in executive function, it was…

Relationship between Impulsivity, Snack Consumption and Children's Weight

PubMed Central

Scholten, Eline W. M.; Schrijvers, Carola T. M.; Nederkoorn, Chantal; Kremers, Stef P. J.; Rodenburg, Gerda

2014-01-01

Background Childhood overweight is a public health problem associated with psychosocial and physical problems. Personality traits, such as impulsivity, may contribute to the development of overweight. Objective This study examines 1) the association between general impulsivity traits (reward sensitivity and disinhibition) and children's weight, 2) the association between impulsivity traits and unhealthy snack consumption, and 3) the potential mediating role of unhealthy snack consumption in the relationship between impulsivity traits and children's weight. Methods Included were 1,377 parent-child dyads participating in the IVO Nutrition and Physical Activity Child cohorT (INPACT). Children had a mean age of 10 years. Parents completed a questionnaire to measure children's unhealthy snack consumption. Children completed a door-opening task to assess reward sensitivity and completed a questionnaire to measure disinhibition. Children's height and weight were measured to calculate their BMI z-scores. Cross-sectional linear regression analyses were performed to test the associations. Results Disinhibition was positively associated with unhealthy snack consumption but not with BMI z-scores. Reward sensitivity was not related to unhealthy snack consumption or to BMI z-scores. Conclusions No evidence was found for a mediating effect of unhealthy snack consumption in the relation between impulsivity traits and children's weight. However, disinhibition appears to have a negative influence on children's unhealthy snack consumption. Future research focusing on food-related impulsivity in addition to general impulsivity will provide additional insight into factors that influence children's unhealthy snack consumption and weight. PMID:24586413

Trait-aggressiveness and impulsivity: role of psychological resilience and childhood trauma in a sample of male prisoners.

PubMed

Carli, Vladimir; Mandelli, Laura; Zaninotto, Leonardo; Alberti, Siegfried; Roy, Alec; Serretti, Alessandro; Sarchiapone, Marco

2014-01-01

One of the major challenges for research in the field of human aggression is the need to define the role of personality and trait-like dimensions, such as impulsivity and aggressiveness, in predisposing to violent behavior. 1) To determine whether trait- aggressiveness and impulsivity may be associated with socio-demographic, clinical and crime history variables in a sample of male prisoners; 2) to detect any association of those traits with measures of early traumatic experiences and current resilience traits. A sample of male prisoners (n = 1356) underwent the Brown-Goodwin Assessment for Lifetime History of Aggression (BGLHA) and the Barratt Impulsivity Scale (BIS). Axis I psychiatric disorders were also assessed. Early traumatic experiences and psychological resilience were detected respectively by the Childhood Trauma Questionnaire (CTQ) and the Connor-Davidson Resilience Scale (CD-RISC). Two non-linear logistic regression models were performed to test for the best predictors of trait-aggressiveness and impulsivity. Subjects with a history of substance use disorders and self-mutilation reported both higher BGLHA and BIS scores. Axis I disorders and suicide attempts were associated with aggressiveness, but not to impulsivity. A consistent correlation was found between BGLHA scores and early traumatic experiences. Resilience was positively correlated to impulsivity but not to aggressiveness scores. Our results support the view that aggressiveness and impulsivity are two different, albeit related trait-like dimensions of personality, having a different relationship with resilience, and, inferentially, a different impact over the development of psychiatric disorders.

Can an intervention based on a serious videogame prior to cognitive behavioral therapy be helpful in bulimia nervosa? A clinical case study.

PubMed

Giner-Bartolomé, Cristina; Fagundo, Ana B; Sánchez, Isabel; Jiménez-Murcia, Susana; Santamaría, Juan J; Ladouceur, Robert; Menchón, José M; Fernández-Aranda, Fernando

2015-01-01

Several studies have highlighted the implications of impulsivity and novelty seeking for both the maintenance and the process of recovery from bulimia nervosa (BN). Cognitive behavioral therapy (CBT) is the treatment of choice for BN, but for some cases, this treatment alone might not be sufficient for reducing the high levels of impulsivity. The paper presents a case report of a patient with BN, examining the effectiveness of using a videogame (VG; Playmancer) as an additional intervention designed to address impulsivity. Psychometric and neuropsychological measures were collected at baseline. After this assessment, Playmancer was applied prior to CBT, following an "A-B-A-C-A" single case experimental design. Impulsivity levels were assessed with the Conner's Continuous Performance Test II (CPT-II). After the Playmancer treatment, the patient started CBT, and the levels of impulsivity were recorded again. Finally, psychometric and neuropsychological measures were collected after treatment. Weekly frequency of binges and vomiting were also recorded during the entire procedure. After the VG intervention, psychometric measures such as anxiety levels, impulsivity and novelty seeking decreased. Regarding the neuropsychological measures, impulsivity levels (measured with the CPT-II) progressively decreased throughout the intervention, and an improvement in decision making capacities was observed. Furthermore, the frequency of binges also decreased during and after the VG intervention. This case report suggests that using the Playmancer VG to reduce impulsivity prior to CBT may enhance the final results of the treatment for BN.

49 CFR 572.172 - Head assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Head assembly and test procedure. 572.172 Section... Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.172 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 420-1000), a six-axis neck...

49 CFR 572.142 - Head assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Head assembly and test procedure. 572.142 Section...-year-Old Child Crash Test Dummy, Alpha Version § 572.142 Head assembly and test procedure. (a) The head assembly (refer to § 572.140(a)(1)(i)) for this test consists of the head (drawing 210-1000), adapter plate...

49 CFR 572.172 - Head assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Head assembly and test procedure. 572.172 Section... Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.172 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 420-1000), a six-axis neck...

49 CFR 572.172 - Head assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Head assembly and test procedure. 572.172 Section... Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.172 Head assembly and test procedure. (a) The head assembly for this test consists of the complete head (drawing 420-1000), a six-axis neck...

49 CFR 572.132 - Head assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Head assembly and test procedure. 572.132 Section... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.132 Head assembly and test procedure. (a) The head assembly (refer to § 572.130(a)(1)(i)) for this test consists of the complete head (drawing...

49 CFR 572.142 - Head assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 7 2011-10-01 2011-10-01 false Head assembly and test procedure. 572.142 Section...-year-Old Child Crash Test Dummy, Alpha Version § 572.142 Head assembly and test procedure. (a) The head assembly (refer to § 572.140(a)(1)(i)) for this test consists of the head (drawing 210-1000), adapter plate...

49 CFR 572.132 - Head assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Head assembly and test procedure. 572.132 Section... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.132 Head assembly and test procedure. (a) The head assembly (refer to § 572.130(a)(1)(i)) for this test consists of the complete head (drawing...

49 CFR 572.142 - Head assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Head assembly and test procedure. 572.142 Section...-year-Old Child Crash Test Dummy, Alpha Version § 572.142 Head assembly and test procedure. (a) The head assembly (refer to § 572.140(a)(1)(i)) for this test consists of the head (drawing 210-1000), adapter plate...

49 CFR 572.132 - Head assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 7 2011-10-01 2011-10-01 false Head assembly and test procedure. 572.132 Section... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.132 Head assembly and test procedure. (a) The head assembly (refer to § 572.130(a)(1)(i)) for this test consists of the complete head (drawing...

49 CFR 572.132 - Head assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Head assembly and test procedure. 572.132 Section... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.132 Head assembly and test procedure. (a) The head assembly (refer to § 572.130(a)(1)(i)) for this test consists of the complete head (drawing...

49 CFR 572.142 - Head assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Head assembly and test procedure. 572.142 Section...-year-Old Child Crash Test Dummy, Alpha Version § 572.142 Head assembly and test procedure. (a) The head assembly (refer to § 572.140(a)(1)(i)) for this test consists of the head (drawing 210-1000), adapter plate...

49 CFR 572.132 - Head assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Head assembly and test procedure. 572.132 Section... Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.132 Head assembly and test procedure. (a) The head assembly (refer to § 572.130(a)(1)(i)) for this test consists of the complete head (drawing...

The effects of a time-based intervention on experienced middle-aged rats

PubMed Central

Peterson, Jennifer R.; Kirkpatrick, Kimberly

2016-01-01

Impulsive behavior is a common symptom in Attention Deficit Hyperactivity Disorder, schizophrenia, drug abuse, smoking, obesity and compulsive gambling. Stable levels of impulsive choice have been found in humans and rats and a recent study reported significant test-retest reliability of impulsive choice behavior after 1 and 5 months in rats. Time-based behavioral interventions have been successful in decreasing impulsive choices. These interventions led to improvements in the ability to time and respond more appropriately to adventitious choices. The current study examined the use of a time-based intervention in experienced, middle-aged rats. This intervention utilized a variable interval schedule previously found to be successful in improving timing and decreasing impulsive choice. This study found that the intervention led to a decrease in impulsive choices and there was a significant correlation between the improvement in self-control and post-intervention temporal precision in middle-aged rats. Although there were no overall group difference in bisection performance, individual differences were observed, suggesting an improvement in timing. This is an important contribution to the field because previous studies have utilized only young rats and because previous research indicates a decrease in general timing abilities with age. PMID:27826006

Partial admission effect on the performance and vibration of a supersonic impulse turbine

NASA Astrophysics Data System (ADS)

Lee, Hang Gi; Shin, Ju Hyun; Choi, Chang-Ho; Jeong, Eunhwan; Kwon, Sejin

2018-04-01

This study experimentally investigates the effects of partial admission on the performance and vibration outcomes of a supersonic impulse turbine with circular nozzles. The turbine of a turbopump for a gas-generator-type liquid rocket engine in the Korea Space Launch Vehicle-II is of the supersonic impulse type with the partial admission configuration for obtaining a high specific power. Partial admission turbines with a low-flow-rate working gas exhibit benefits over turbines with full admission, such as loss reduction, ease of controllability of the turbine power output, and simple turbine configurations with separate starting sections. However, the radial force of the turbine rotor due to the partial admission causes an increase in turbine vibration. Few experimental studies have previously been conducted regarding the partial admission effects on supersonic impulse turbines with circular nozzles. In the present study, performance tests of supersonic impulse turbines with circular nozzles were conducted for various partial admission ratios using a turbine test facility with high-pressure air in order to investigate the resulting aerodynamic performance and vibration. Four types of turbines with partial admission ratios of 0.17, 0.42, 0.75 and 0.83 were tested. Results show that the efficiencies at the design point increase linearly as the partial admission ratios increase. Moreover, as the velocity ratios increase, the difference in efficiency from the reference turbine with a partial admission ratio of 0.83 becomes increasingly significant, and the magnitudes of these differences are proportional to the square of the velocity ratios. Likewise, the decrease in the partial admission ratio results in an increase in the turbine vibration level owing to the increase in the radial force.

Apollo Contour Rocket Nozzle in the Propulsion Systems Laboratory

NASA Image and Video Library

1964-07-21

Bill Harrison and Bud Meilander check the setup of an Apollo Contour rocket nozzle in the Propulsion Systems Laboratory at the National Aeronautics and Space Administration (NASA) Lewis Research Center. The Propulsion Systems Laboratory contained two 14-foot diameter test chambers that could simulate conditions found at very high altitudes. The facility was used in the 1960s to study complex rocket engines such as the Pratt and Whitney RL-10 and rocket components such as the Apollo Contour nozzle, seen here. Meilander oversaw the facility’s mechanics and the installation of test articles into the chambers. Harrison was head of the Supersonic Tunnels Branch in the Test Installations Division. Researchers sought to determine the impulse value of the storable propellant mix, classify and improve the internal engine performance, and compare the results with analytical tools. A special setup was installed in the chamber that included a device to measure the thrust load and a calibration stand. Both cylindrical and conical combustion chambers were examined with the conical large area ratio nozzles. In addition, two contour nozzles were tested, one based on the Apollo Service Propulsion System and the other on the Air Force’s Titan transtage engine. Three types of injectors were investigated, including a Lewis-designed model that produced 98-percent efficiency. It was determined that combustion instability did not affect the nozzle performance. Although much valuable information was obtained during the tests, attempts to improve the engine performance were not successful.

Impacts of small vestibular schwannoma on community ambulation, postural, and ocular control.

PubMed

Low Choy, Nancy L; Lucey, Mary-Therese M; Lewandowski, Susan L; Panizza, Benedict J

2017-05-01

To investigate balance, community mobility, gaze instability, and dizziness handicap and assess falls risk in people who are conservatively managed with small vestibular schwannoma (VS). Cross-sectional study with controls. The study involved 18 people (mean age 58.7 ± 12.2 years) diagnosed with VS (<12 mm) and 22 age-matched controls (mean age 56.9 ± 8.0 years). Measures included standing on firm and foam surfaces with feet apart, then together with eyes open and closed, Timed Up and Go (TUG) test and dual TUG test, Dynamic Gait Index, 6-Minute Walk Test, Halmagyi Impulse Test, Dynamic Visual Acuity Test, and the Dizziness Handicap Inventory. The clinical group failed more trials standing feet together on foam with eyes closed (P < .05); had inferior mobility and walked more slowly with divided attention (P < .05); had more difficulty walking with head movement, negotiating obstacles, and using stairs (P < .01); and walked shorter distances (P < .001) than controls. Reduced gaze stability (P < .01) and higher total (P = .007) and subcategory dizziness handicap scores (P < .05) were revealed compared to age-matched controls. Although outcomes for the clinical group are inferior to the control group across all measures and the dizziness impact is higher, the results fall in the low-risk category for falls. Preliminary data (level 4 evidence) support using a suite of clinical measures to monitor people with VS during conservative management. 4 Laryngoscope, 127:1147-1152, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Vertigo with sudden hearing loss: audio-vestibular characteristics.

PubMed

Pogson, Jacob M; Taylor, Rachael L; Young, Allison S; McGarvie, Leigh A; Flanagan, Sean; Halmagyi, G Michael; Welgampola, Miriam S

2016-10-01

Acute vertigo with sudden sensorineural hearing loss (SSNHL) is a rare clinical emergency. Here, we report the audio-vestibular test profiles of 27 subjects who presented with these symptoms. The vestibular test battery consisted of a three-dimensional video head impulse test (vHIT) of semicircular canal function and recording ocular and cervical vestibular-evoked myogenic potentials (oVEMP, cVEMP) to test otolith dysfunction. Unlike vestibular neuritis, where the horizontal and anterior canals with utricular function are more frequently impaired, 74 % of subjects with vertigo and SSNHL demonstrated impairment of the posterior canal gain (0.45 ± 0.20). Only 41 % showed impairment of the horizontal canal gains (0.78 ± 0.27) and 30 % of the anterior canal gains (0.79 ± 0.26), while 38 % of oVEMPs [asymmetry ratio (AR) = 41.0 ± 41.3 %] and 33 % of cVEMPs (AR = 47.3 ± 41.2 %) were significantly asymmetrical. Twenty-three subjects were diagnosed with labyrinthitis/labyrinthine infarction in the absence of evidence for an underlying pathology. Four subjects had a definitive diagnosis [Ramsay Hunt Syndrome, vestibular schwannoma, anterior inferior cerebellar artery (AICA) infarction, and traction injury]. Ischemia involving the common-cochlear or vestibulo-cochlear branches of the labyrinthine artery could be the simplest explanation for vertigo with SSNHL. Audio-vestibular tests did not provide easy separation between ischaemic and non-ischaemic causes of vertigo with SSNHL.

Energetics and dynamics of simple impulsive solar flares

NASA Technical Reports Server (NTRS)

Starr, R.; Heindl, W. A.; Crannell, C. J.; Thomas, R. J.; Batchelor, D. A.; Magun, A.

1987-01-01

Flare energetics and dynamics were studied using observations of simple impulsive spike bursts. A large, homogeneous set of events was selected to enable the most definite tests possible of competing flare models, in the absence of spatially resolved observations. The emission mechanisms and specific flare models that were considered in this investigation are described, and the derivations of the parameters that were tested are presented. Results of the correlation analysis between soft and hard X-ray energetics are also presented. The ion conduction front model and tests of that model with the well-observed spike bursts are described. Finally, conclusions drawn from this investigation and suggestions for future studies are discussed.

Comparing the drawings of children with attention deficit hyperactivity disorder with normal children.

PubMed

Haghighi, Mahnaz; Khaterizadeh, Maedeh; Chalbianloo, Gholamreza; Toobaei, Sholeh; Ghanizadeh, Ahmad

2014-10-01

Attention deficit hyperactivity disorder (ADHD) is the most common behavioral problem during childhood and in school-aged children. Various projection drawings have been designed for assessing children's personality and psychological disorders including the tests of draw a person (DAP) and draw a family (DAF). We aimed to compare the differences between typically developing children and children with ADHD using these tests. In this case-control study, all the 9-10 year-old boy students studying at the third and fourth grades were enrolled from schools in the 2nd educational district of Shiraz, south of Iran. Eighty students were then selected and enrolled into the ADHD group and the control group. The Diagnostic and Statistical Manual of Mental Disorders, 4th edition- text Revised (DSM-IV-TR), and the Child Symptoms Inventory were used to diagnose the children with ADHD. We evaluated and analyzed impulsiveness, non-impulsiveness, emotional problems and incompatibility indices in the DAP and DAF tests in each group. A significant difference was found in the indices of incompatibility and emotional problems, impulsiveness, non-impulsiveness and DAF between typically developing children and those with ADHD. The mean (±SD) total scores of the above mentioned indices in the ADHD group were 19.79(±2.94), 12.31(±1.84), 5.26(±2.29) and 5.89(±2.13), respectively (P<0.001). The corresponding figures for these indices in the normal group were 12.11(±4.74), 5.63(±2), 10.36± (2.33) and 2.88(±2.13), respectively (P<0.001). Significant differences were obtained between the control group and children with ADHD using these two drawing tests. The rate of impulsivity and emotional problems indices in drawings of children with ADHD was markedly more common than those of the typically developing children. This suggests the need for further assessment to screen ADHD.

Changes in cocaine consumption are associated with fluctuations in self-reported impulsivity and gambling decision-making.

PubMed

Hulka, L M; Vonmoos, M; Preller, K H; Baumgartner, M R; Seifritz, E; Gamma, A; Quednow, B B

2015-10-01

In cross-sectional studies, cocaine users generally display elevated levels of self-reported and cognitive impulsivity. To what extent these impairments are stable v. variable markers of cocaine use disorder, and, thus, are pre-existing or drug-induced, has not yet been systematically investigated. We conducted a longitudinal study with cocaine users who changed or maintained their consumption intensity, measuring self-reported impulsivity with the Barratt Impulsiveness Scale (BIS-11), and cognitive impulsivity with the Rapid Visual Processing task (RVP), Iowa Gambling task (IGT), and Delay Discounting task (DD) at baseline and at 1-year follow-up. We assessed 48 psychostimulant-naive controls and 19 cocaine users with decreased, 19 users with increased, and 19 users with unchanged cocaine intake after 1 year as confirmed by hair analysis. Results of linear multilevel modelling showed significant group × time interactions for the BIS-11 total score and the IGT total card ratio. Increasers showed a trend for elevated scores, whereas decreasers exhibited reduced self-reported impulsivity scores within 1 year. Surprisingly, increasers' IGT performance was improved after 1 year, whereas decreasers' performance deteriorated. By contrast, neither RVP response bias B" nor DD total score showed substantial group × time interactions. Importantly, BIS-11 and DD revealed strong test-retest reliabilities. Self-reported impulsivity (BIS-11) and decision-making impulsivity (IGT) covary with changing cocaine use, whereas response bias and delay discounting remain largely unaffected. Thus, self-reported impulsivity and gambling decision-making were strongly state-dependent in a stimulant-using population and may be suitable to monitor treatment success, whereas delay of gratification was confirmed as a potential endophenotype of stimulant addiction.

Does oxygen delivery explain interindividual variation in forearm critical impulse?

PubMed

Kellawan, J Mikhail; Bentley, Robert F; Bravo, Michael F; Moynes, Jackie S; Tschakovsky, Michael E

2014-11-01

Within individuals, critical power appears sensitive to manipulations in O2 delivery. We asked whether interindividual differences in forearm O2 delivery might account for a majority of the interindividual differences in forearm critical force impulse (critical impulse), the force analog of critical power. Ten healthy men (24.6 ± 7.10 years) completed a maximal effort rhythmic handgrip exercise test (1 sec contraction-2 sec relaxation) for 10 min. The average of contraction impulses over the last 30 sec quantified critical impulse. Forearm brachial artery blood flow (FBF; echo and Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured continuously. O2 delivery (FBF arterial oxygen content (venous blood [hemoglobin] and oxygen saturation from pulse oximetry)) and forearm vascular conductance (FVC; FBF·MAP(-1)) were calculated. There was a wide range in O2 delivery (59.98-121.15 O2 mL·min(-1)) and critical impulse (381.5-584.8 N) across subjects. During maximal effort exercise, O2 delivery increased rapidly, plateauing well before the declining forearm impulse and explained most of the interindividual differences in critical impulse (r(2) = 0.85, P < 0.01). Both vasodilation (r(2) = 0.64, P < 0.001) and the exercise pressor response (r(2) = 0.33, P < 0.001) independently contributed to interindividual differences in FBF. In conclusion, interindividual differences in forearm O2 delivery account for most of the interindividual variation in critical impulse. Furthermore, individual differences in pressor response play an important role in determining differences in O2 delivery in addition to vasodilation. The mechanistic origins of this vasodilatory and pressor response heterogeneity across individuals remain to be determined. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Does oxygen delivery explain interindividual variation in forearm critical impulse?

PubMed Central

Kellawan, J. Mikhail; Bentley, Robert F.; Bravo, Michael F.; Moynes, Jackie S.; Tschakovsky, Michael E.

2014-01-01

Abstract Within individuals, critical power appears sensitive to manipulations in O2 delivery. We asked whether interindividual differences in forearm O2 delivery might account for a majority of the interindividual differences in forearm critical force impulse (critical impulse), the force analog of critical power. Ten healthy men (24.6 ± 7.10 years) completed a maximal effort rhythmic handgrip exercise test (1 sec contraction‐2 sec relaxation) for 10 min. The average of contraction impulses over the last 30 sec quantified critical impulse. Forearm brachial artery blood flow (FBF; echo and Doppler ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured continuously. O2 delivery (FBF arterial oxygen content (venous blood [hemoglobin] and oxygen saturation from pulse oximetry)) and forearm vascular conductance (FVC; FBF·MAP−1) were calculated. There was a wide range in O2 delivery (59.98–121.15 O2 mL·min−1) and critical impulse (381.5–584.8 N) across subjects. During maximal effort exercise, O2 delivery increased rapidly, plateauing well before the declining forearm impulse and explained most of the interindividual differences in critical impulse (r2 = 0.85, P < 0.01). Both vasodilation (r2 = 0.64, P < 0.001) and the exercise pressor response (r2 = 0.33, P < 0.001) independently contributed to interindividual differences in FBF. In conclusion, interindividual differences in forearm O2 delivery account for most of the interindividual variation in critical impulse. Furthermore, individual differences in pressor response play an important role in determining differences in O2 delivery in addition to vasodilation. The mechanistic origins of this vasodilatory and pressor response heterogeneity across individuals remain to be determined. PMID:25413323

Analysis of 100-lb(sub f) (445-N) LO2-LCH4 Reaction Control Engine Impulse Bit Performance

NASA Technical Reports Server (NTRS)

Marshall, William M.; Klenhenz, Julie E.

2012-01-01

Recently, liquid oxygen-liquid methane (LO2-LCH4) has been considered as a potential green propellant alternative for future exploration missions. The Propulsion and Cryogenic Advanced Development (PCAD) project was tasked by NASA to develop this propulsion combination to enable safe and cost-effective exploration missions. To date, limited experience with such combinations exist, and as a result a comprehensive test program is critical to demonstrating with the viability of implementing such a system. The NASA Glenn Research Center conducted a test program of a 100-lbf (445-N) reaction control engine (RCE) at the Center s Altitude Combustion Stand (ACS), focusing on altitude testing over a wide variety of operational conditions. The ACS facility includes unique propellant conditioning feed systems (PCFS), which allow precise control of propellant inlet conditions to the engine. Engine performance as a result of these inlet conditions was examined extensively during the test program. This paper is a companion to the previous specific impulse testing paper, and discusses the pulsed-mode operation portion of testing, with a focus on minimum impulse bit (MIB) and repeatable pulse performance. The engine successfully demonstrated target MIB performance at all conditions, as well as successful demonstration of repeatable pulse widths. Some anomalous conditions experienced during testing are also discussed, including a double pulse phenomenon, which was not noted in previous test programs for this engine.

Endogenous Opioid Signaling in the Medial Prefrontal Cortex is Required for the Expression of Hunger-Induced Impulsive Action.

PubMed

Selleck, Ryan A; Lake, Curtis; Estrada, Viridiana; Riederer, Justin; Andrzejewski, Matthew; Sadeghian, Ken; Baldo, Brian A

2015-09-01

Opioid transmission and dysregulated prefrontal cortex (PFC) activity have both been implicated in the inhibitory-control deficits associated with addiction and binge-type eating disorders. What remains unknown, however, is whether endogenous opioid transmission within the PFC modulates inhibitory control. Here, we compared intra-PFC opioid manipulations with a monoamine manipulation (d-amphetamine), in two sucrose-reinforced tasks: progressive ratio (PR), which assays the motivational value of an incentive, and differential reinforcement of low response rates (DRLs), a test of inhibitory control. Intra-PFC methylnaloxonium (M-NX, a limited diffusion opioid antagonist) was given to rats in a 'low-drive' condition (2-h food deprivation), and also after a motivational shift to a 'high-drive' condition (18-h food deprivation). Intra-PFC DAMGO (D-[Ala2,N-MePhe4, Gly-ol]-enkephalin; a μ-opioid agonist) and d-amphetamine were also tested in both tasks, under the low-drive condition. Intra-PFC M-NX nearly eliminated impulsive action in DRL engendered by hunger, at a dose (1 μg) that significantly affected neither hunger-induced PR enhancement nor hyperactivity. At a higher dose (3 μg), M-NX eliminated impulsive action and returned PR breakpoint to low-drive levels. Conversely, intra-PFC DAMGO engendered 'high-drive-like' effects: enhancement of PR and impairment of DRL performance. Intra-PFC d-amphetamine failed to produce effects in either task. These results establish that endogenous PFC opioid transmission is both necessary and sufficient for the expression of impulsive action in a high-arousal, high-drive appetitive state, and that PFC-based opioid systems enact functionally unique effects on food impulsivity and motivation relative to PFC-based monoamine systems. Opioid antagonists may represent effective treatments for a range of psychiatric disorders with impulsivity features.

Effects of amphetamine exposure in adolescence or young adulthood on inhibitory control in adult male and female rats

PubMed Central

Hammerslag, Lindsey R.; Waldman, Alex J.; Gulley, Joshua M.

2014-01-01

Heightened impulsivity is a feature of some psychiatric disorders, including addiction, that also have sex-specific patterns of expression. The relationship between addiction and impulsivity may be driven by drug-induced changes in behavior caused by long term adaptations in signaling within the medial prefrontal cortex (mPFC). Here, we used a response inhibition task that is sensitive to changes in mPFC function to examine the effects of sex and exposure to amphetamine (AMPH) on impulsive action and vigilance. We also examined drug-induced alterations in glutamatergic and dopaminergic signaling through challenge injections with the NMDA receptor antagonist MK-801 (dizocilpine) and AMPH. Male and female Sprague Dawley rats were injected (i.p.) with saline or 3 mg/kg AMPH every other day during adolescence (postnatal day (P) 27–45) or adulthood (P85–103). Starting on P125–135, rats were tested for their ability to lever press for a food reward during periods of signaled availability and withhold responding during a “premature response” phase. In experiment 1, rats received challenge injections (i.p.) of MK-801 and AMPH followed by tests of task performance and locomotor activity. In experiment 2, rats received intra-mPFC infusion of MK-801. We found that females had better inhibitory control and poorer vigilance than males and that AMPH exposure had both sex- and age-of-exposure dependent effects on impulsivity. Systemic drug challenges disrupted task performance, particularly in females, and increased impulsivity while intra-mPFC infusions had modest effects. AMPH exposure did not affect responses to drug challenges. Together, these results suggest that sex mediates both trait and drug-induced impulsivity. PMID:24462963

A comparison of university student and community gamblers: Motivations, impulsivity, and gambling cognitions

PubMed Central

Marmurek, Harvey H. C.; Switzer, Jessica; D’Alvise, Joshua

2014-01-01

Background and aims: The present study tested whether the associations among motivational, cognitive, and personality correlates of problem gambling severity differed across university student gamblers (n = 123) and gamblers in the general adult community (n = 113). Methods: The participants completed a survey that included standardized measures of gambling motivation, gambling related cognitions, and impulsivity. The survey also asked participants to report the forms of gambling in which they engaged to test whether gambling involvement (number of different forms of gambling) was related to problem gambling severity. After completing the survey, participants played roulette online to examine whether betting patterns adhered to the gambler’s fallacy. Results: Gambling involvement was significantly related to problem gambling severity for the community sample but not for the student sample. A logistic regression analysis that tested the involvement, motivation, impulsivity and cognitive correlates showed that money motivation and gambling related cognitions were the only significant independent predictors of gambling severity. Adherence to the gambler’s fallacy was stronger for students than for the community sample, and was associated with gambling related cognitions. Discussion: The motivational, impulsivity and cognitive, and correlates of problem gambling function similarly in university student gamblers and in gamblers from the general adult community. Interventions for both groups should focus on the financial and cognitive supports of problem gambling. PMID:25215214

The Effect of Local Violence on Children’s Attention and Impulse Control

PubMed Central

Tirado-Strayer, Nicole; Papachristos, Andrew V.; Raver, C. Cybele

2012-01-01

Objectives. We examined whether the burden of violence in a child’s community environment alters the child’s behavior and functioning in the classroom setting. Methods. To identify the effects of local violence, we exploited variation in the timing of local homicides, based on data from the Chicago Police Department, relative to the timing of interview assessments conducted as part of a randomized controlled trial conducted with preschoolers in Head Start programs from 2004–2006, the Chicago School Readiness Project. We compared children’s scores when exposed to recent local violence with scores when no recent violence had occurred to identify causal effects. Results. When children were assessed within a week of a homicide that occurred near their home, they exhibited lower levels of attention and impulse control and lower preacademic skills. The analysis showed strong positive effects of local violence on parental distress, providing suggestive evidence that parental responses may be a likely pathway by which local violence affects young children. Conclusions. Exposure to homicide generates acute psychological distress among caregivers and impairs children’s self-regulatory behavior and cognitive functioning. PMID:23078491

Experimental Investigations on Two Potential Sound Diffuseness Measures in Enclosures

NASA Astrophysics Data System (ADS)

Bai, Xin

This study investigates two different approaches to measure sound field diffuseness in enclosures from monophonic room impulse responses. One approach quantifies sound field diffuseness in enclosures by calculating the kurtosis of the pressure samples of room impulse responses. Kurtosis is a statistical measure that is known to describe the peakedness or tailedness of the distribution of a set of data. High kurtosis indicates low diffuseness of the sound field of interest. The other one relies on multifractal detrended fluctuation analysis which is a way to evaluate the statistical self-affinity of a signal to measure diffuseness. To test these two approaches, room impulse responses are obtained under varied room-acoustic diffuseness configurations, achieved by using varied degrees of diffusely reflecting interior surfaces. This paper will analyze experimentally measured monophonic room impulse responses, and discuss results from these two approaches.

The development of a brief self-report questionnaire to measure 'recent' rash impulsivity: a preliminary investigation of its validity and association with recent alcohol consumption.

PubMed

Mayhew, Matthew J; Powell, Jane H

2014-11-01

Traditionally, impulsivity has been regarded as a stable trait. However, a series of longitudinal and behavioural laboratory studies has found that impulsivity can fluctuate within individuals, suggesting that it has a state as well as a trait manifestation. Whilst existing impulsivity questionnaires tap the former, there is no self-report instrument to assess recent fluctuations in impulsivity. Research aims and design The present study set out to develop and undertake preliminary validation of a measure of 'recent' impulsivity, focusing in particular on Rash Impulsivity. Part of the construct validation of the resulting Recent Rash Impulsivity Scale (RRIS) entailed examining its association with recent alcohol intake, since there are well-documented reciprocal relationships between alcohol consumption and inhibitory control. In developing the RRIS, items from existing trait impulsivity questionnaires were converted into a 'previous two weeks' format. The pilot RRIS was then administered, along with a parallel trait version (Trait Rash Impulsivity Scale; TRIS) and a well-established trait impulsivity measure (the BIS-11; Patton, Stanford & Barratt, 1995), to two cohorts of first-year undergraduates aged 17 to 25 (N=240), on two occasions one month apart. Information about habitual and recent alcohol intake was also gathered. Factor analyses on both the RRIS and TRIS identified two factors: 'Cognitive Impulsivity' (CogImp) and 'Motor Impulsivity' (MotImp). Consistent with the RRIS being sensitive to fluctuations in impulsivity, it was found that, as predicted: i) the RRIS was somewhat less strongly correlated than the TRIS with an established trait measure (the BIS-11; Patton et al., 1995); ii) the test-retest stability of 'Total' scores (CogImp and MotImp) was weaker for the RRIS than the TRIS; iii) there was evidence that the RRIS MotImp and Total scales were more strongly predicted by recent alcohol intake than were their trait equivalents; and iv) the RRIS CogImp and Total scales correlated more strongly with their trait equivalents in participants whose alcohol consumption had remained stable recently (relative to their habitual intake), compared to those whose consumption had recently changed. These data suggest that transient changes in impulsivity can be assessed via self-report, and that the RRIS is sensitive to recent changes in alcohol intake. Subject to a more intensive and detailed validation, it is thus promising as a tool for tapping and characterising fluctuations in behavioural control and for exploring a range of factors to which this might be associated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analyses and tests for design of an electro-impulse de-icing system

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.; Schrag, R. L.; Bernhart, W. D.; Friedberg, R. A.

1985-01-01

De-icing of aircraft by using the electro-magnetic impulse phenomenon was proposed and demonstrated in several European countries. However, it is not available as a developed system due to lack of research on the basic physical mechanisms and necessary design parameters. The de-icing is accomplished by rapidly discharging high voltage capacitors into a wire coil rigidly supported just inside the aircraft skin. Induced eddy currents in the skin create a repulsive force resulting in a hammer-like force which cracks, de-bonds, and expels ice on the skin surface. The promised advantages are very low energy, high reliability of de-icing, and low maintenance. Three years of Electo-Impulse De-icing (EIDI) research is summarized and the analytical studies and results of testing done in the laboratory, in the NASA Icing Research Tunnel, and in flight are presented. If properly designed, EIDI was demonstrated to be an effective and practical ice protection system for small aircraft, turbojet engine inlets, elements of transport aircraft, and shows promise for use on helicopter rotor blades. Included are practical techniques of fabrication of impulse coils and their mountings. The use of EIDI with nonmetallic surface materials is also described.

Atomoxetine reduces hyperactive/impulsive behaviours in neurokinin-1 receptor 'knockout' mice.

PubMed

Pillidge, Katharine; Porter, Ashley J; Vasili, Temis; Heal, David J; Stanford, S Clare

2014-12-01

Mice with functional ablation of the neurokinin-1 receptor gene (NK1R(-/-)) display behavioural abnormalities which resemble the hyperactivity, inattention and impulsivity seen in Attention Deficit Hyperactivity Disorder (ADHD). Here, we investigated whether the established ADHD treatment, atomoxetine, alleviates these abnormalities when tested in the light/dark exploration box (LDEB) and 5-Choice Serial Reaction-Time Task (5-CSRTT). Separate cohorts of mice were tested in the 5-CSRTT and LDEB after treatment with no injection, vehicle or atomoxetine (5-CSRTT: 0.3, 3 or 10mg/kg; LDEB: 1, 3 or 10mg/kg). Atomoxetine reduced the hyperactivity displayed by NK1R(-/-) mice in the LDEB at a dose (3mg/kg) which did not affect the locomotor activity of wildtypes. Atomoxetine (10mg/kg) also reduced impulsivity in NK1R(-/-) mice, but not wildtypes, in the 5-CSRTT. No dose of drug affected attention in either genotype. This evidence that atomoxetine reduces hyperactive/impulsive behaviours in NK1R(-/-) mice consolidates the validity of using NK1R(-/-) mice in research of the aetiology and treatment of ADHD. Copyright © 2014. Published by Elsevier Inc.

Testing the Impulsiveness of Solar Flare Heating through Analysis of Dynamic Atmospheric Response

NASA Astrophysics Data System (ADS)

Newton, E. K.; Emslie, A. G.; Mariska, J. T.

1996-03-01

One crucial test of a solar flare energy transport model is its ability to reproduce the characteristics of the atmospheric motions inferred from soft X-ray line spectra. Using a recently developed diagnostic, the velocity differential emission measure (VDEM), we can obtain from observations a physical measure of the amount of soft X-ray mitting plasma flowing at each velocity, v, and hence the total momentum of the upflowing plasma, without approximation or parametric fitting. We have correlated solar hard X-ray emission profiles by the Yohkoh Hard X-ray telescope with the mass and momentum histories inferred from soft X-ray line profiles observed by the Yohkoh Bragg crystal spectrometers. For suitably impulsive hard X-ray emission, an analysis of the hydrodynamic equations predicts a proportionality between the hard X-ray intensity and the second time derivative of the soft X-ray mitting plasma's momentum. This relationship is borne out by an analysis of 18 disk-center impulsive flares of varying durations, thereby lending support to the hypothesis that a prompt energy deposition mechanism, such as an energetic electron flux, is indeed responsible for the soft X-ray response observed in the rise phase of sufficiently impulsive solar flares.

Atomoxetine reduces hyperactive/impulsive behaviours in neurokinin-1 receptor ‘knockout’ mice

PubMed Central

Pillidge, Katharine; Porter, Ashley J.; Vasili, Temis; Heal, David J.; Stanford, S. Clare

2014-01-01

Background Mice with functional ablation of the neurokinin-1 receptor gene (NK1R−/−) display behavioural abnormalities which resemble the hyperactivity, inattention and impulsivity seen in Attention Deficit Hyperactivity Disorder (ADHD). Here, we investigated whether the established ADHD treatment, atomoxetine, alleviates these abnormalities when tested in the light/dark exploration box (LDEB) and 5-Choice Serial Reaction-Time Task (5-CSRTT). Methods Separate cohorts of mice were tested in the 5-CSRTT and LDEB after treatment with no injection, vehicle or atomoxetine (5-CSRTT: 0.3, 3 or 10 mg/kg; LDEB: 1, 3 or 10 mg/kg). Results Atomoxetine reduced the hyperactivity displayed by NK1R−/− mice in the LDEB at a dose (3 mg/kg) which did not affect the locomotor activity of wildtypes. Atomoxetine (10 mg/kg) also reduced impulsivity in NK1R−/− mice, but not wildtypes, in the 5-CSRTT. No dose of drug affected attention in either genotype. Conclusions This evidence that atomoxetine reduces hyperactive/impulsive behaviours in NK1R−/− mice consolidates the validity of using NK1R−/− mice in research of the aetiology and treatment of ADHD. PMID:25450119

Multiple Impulse Therapy in the Assessment of Paraspinal Muscle Tone in Patients with Low Back Pain.

PubMed

Haładaj, Robert; Topol, Mirosław

2016-11-30

Back pain is quite common in contemporary society, whose expectations of an effective analgesic therapy in conservative treatment lead to a necessity of searching for new diagnostic and therapeutic methods in physiotherapy. Out of the numerous physical therapy methods, Multiple Impulse Therapy (MIT) deserves special consideration. This paper aims to present and analyse the outcomes of MIT concerning paraspinal muscle tone and pain intensity in patients with low back pain. The study enrolled 117 patients (50 women and 67 men; average age of 45.3 yrs) with lumbar conditions confirmed by imaging studies. The participants received five MIT sessions within 14 days. Moreover, both before and after the therapy all the patients underwent bilateral assessment of the paraspinal muscle tone by surface electromyography (sEMG) with the NoraxonMyoTrace 400 system and an interactive head of the PulStarFRAS device. A VAS was used for evaluation of pain severity. The analysis of significance of differences between scores before and after treatment showed that all the parameters changed significantly (MIT: 11.11 Ibf before and 8.89 Ibf after the therapy; VAS: 6.04 before and 3.38 afterwards; sEMG: 9.29uV before and 7.51uV afterwards). 1. Multiple Impulse Therapy (MIT) is an effective and non-invasive method of back pain treatment. 2. MIT significantly reduces paraspinal muscle tone, as confirmed by sEMG results, and shows a strong analgesic effect.

A Porcine Model of Traumatic Brain Injury via Head Rotational Acceleration

PubMed Central

Cullen, D. Kacy; Harris, James P.; Browne, Kevin D.; Wolf, John A; Duda, John E.; Meaney, David F.; Margulies, Susan S.; Smith, Douglas H.

2017-01-01

Unique from other brain disorders, traumatic brain injury (TBI) generally results from a discrete biomechanical event that induces rapid head movement. The large size and high organization of the human brain makes it particularly vulnerable to traumatic injury from rotational accelerations that can cause dynamic deformation of the brain tissue. Therefore, replicating the injury biomechanics of human TBI in animal models presents a substantial challenge, particularly with regard to addressing brain size and injury parameters. Here we present the historical development and use of a porcine model of head rotational acceleration. By scaling up the rotational forces to account for difference in brain mass between swine and humans, this model has been shown to produce the same tissue deformations and identical neuropathologies found in human TBI. The parameters of scaled rapid angular accelerations applied for the model reproduce inertial forces generated when the human head suddenly accelerates or decelerates in falls, collisions, or blunt impacts. The model uses custom-built linkage assemblies and a powerful linear actuator designed to produce purely impulsive nonimpact head rotation in different angular planes at controlled rotational acceleration levels. Through a range of head rotational kinematics, this model can produce functional and neuropathological changes across the spectrum from concussion to severe TBI. Notably, however, the model is very difficult to employ, requiring a highly skilled team for medical management, biomechanics, neurological recovery, and specialized outcome measures including neuromonitoring, neurophysiology, neuroimaging, and neuropathology. Nonetheless, while challenging, this clinically relevant model has proven valuable for identifying mechanisms of acute and progressive neuropathologies as well as for the evaluation of noninvasive diagnostic techniques and potential neuroprotective treatments following TBI. PMID:27604725

Early age of e-cigarette use onset mediates the association between impulsivity and e-cigarette use frequency in youth.

PubMed

Bold, Krysten W; Morean, Meghan E; Kong, Grace; Simon, Patricia; Camenga, Deepa R; Cavallo, Dana A; Krishnan-Sarin, Suchitra

2017-12-01

Identifying risk factors for youth e-cigarette use is critical, given high rates of e-cigarette use and unknown health effects of long-term use. The current study examined whether an early age of onset of e-cigarette use mediates the association between impulsivity and e-cigarette frequency. Cross-sectional survey data of e-cigarette users (n=927) were collected from 8 high schools in southeastern Connecticut. The sample was 44.7% female (mean age 16.2 [SD=1.2], mean age of e-cigarette onset 14.7 [SD=1.6]). Two domains of self-reported, trait impulsivity were assessed using the abbreviated Barratt Impulsiveness Scale: impaired self-regulation (e.g., problems with concentration or self-control) and behavioral impulsivity (e.g., doing things without thinking). Mediation was tested with Mplus, and the model included school as a cluster variable and controlled for covariates related to e-cigarette use (i.e., sex, age, race, peer use, and other tobacco products ever tried). The hypothesized mediation was supported for both domains of impulsivity (impaired self-regulation a 1 b=0.09, SE=0.02, 95%CI [0.03-0.14], p=.002; behavioral impulsivity a 2 b=0.07, SE=0.03, 95%CI [.01-.14], p=0.03). Specifically, impaired self-regulation (B=-0.33, SE=0.06, p<0.001) and behavioral impulsivity (B=-0.26, SE=0.11, p=0.02) predicted trying e-cigarettes at an earlier age, and earlier initiation was associated with more days of e-cigarette use in the past month (B=-0.28, SE=0.08, p<0.001). Adolescents who endorse aspects of impulsivity, such as acting without thinking, are at greater risk for more frequent e-cigarette use through an early age of e-cigarette initiation. Further research is needed to evaluate these relationships longitudinally and to develop targeted e-cigarette interventions for impulsive youth. Copyright © 2017 Elsevier B.V. All rights reserved.

Impulsivity traits in patients with multiple sclerosis.

PubMed

Toro, Jaime; Blanco, Luisa; Orozco-Cabal, Luis Felipe; Díaz, Camilo; Reyes, Saúl; Burbano, Lisseth; Cuéllar-Giraldo, David Felipe; Duque, Alejandra; Patiño, Jorge; Cortés, Fabián

2018-05-01

Multiple sclerosis (MS) is a demyelinating disease with a lifetime prevalence of 4.41/100000 in Bogota, Colombia. It is known that it can be related with neuropsychiatric disorders, increasing by a factor of three the prevalence of depression in MS patients compared to general population. However, less attention has been given to the association between MS and impulsive behavior. This cross-sectional study compared the levels of impulsivity controlling for the presence of MS. 60 patients with MS and 60 sex- and age-matched subjects without MS were included. In order to assess depression and impulsivity, participants completed the 13-item short form of the Beck Depression Inventory (BDI-SF), the self-report Barratt Impulsiveness Scale version 11 (BIS-11) and the Immediate and Delayed Memory Tasks (IMT-DMT) as an objective measure of impulsive behavior. Total scores, motor and cognitive subscales on the BIS-11 were significantly higher in the MS group. However, median BDI-SF score was also higher in MS patients than in subjects without MS (p < 0.001). To rule out depression as a confounding factor, stratification was performed using the BDI-SF score. In the subgroup of individuals with a BDI-SF< 8, the BIS-11 cognitive subscale scores were significantly higher in patients with MS than in subjects without MS (p = 0.041). In the IMT/DMT test, subjects with MS had a fewer number of correct detections than did subjects without MS, after controlling for BDI-SF score (p = 0.0001/p = 0.003). The ratio of commission errors to correct detections in the IMT was significantly higher in the MS group (p = 0.011). Patients with MS showed higher levels of cognitive impulsivity than subjects without MS. Objective measures for impulsiveness further support this finding. Impulsiveness scales scores might be biased by depression, which should be considered when assessing impulsivity in MS. Copyright © 2018 Elsevier B.V. All rights reserved.

Can an intervention based on a serious videogame prior to cognitive behavioral therapy be helpful in bulimia nervosa? A clinical case study

PubMed Central

Giner-Bartolomé, Cristina; Fagundo, Ana B.; Sánchez, Isabel; Jiménez-Murcia, Susana; Santamaría, Juan J.; Ladouceur, Robert; Menchón, José M.; Fernández-Aranda, Fernando

2015-01-01

Background: Several studies have highlighted the implications of impulsivity and novelty seeking for both the maintenance and the process of recovery from bulimia nervosa (BN). Cognitive behavioral therapy (CBT) is the treatment of choice for BN, but for some cases, this treatment alone might not be sufficient for reducing the high levels of impulsivity. The paper presents a case report of a patient with BN, examining the effectiveness of using a videogame (VG; Playmancer) as an additional intervention designed to address impulsivity. Design: Psychometric and neuropsychological measures were collected at baseline. After this assessment, Playmancer was applied prior to CBT, following an “A-B-A-C-A” single case experimental design. Impulsivity levels were assessed with the Conner’s Continuous Performance Test II (CPT-II). After the Playmancer treatment, the patient started CBT, and the levels of impulsivity were recorded again. Finally, psychometric and neuropsychological measures were collected after treatment. Weekly frequency of binges and vomiting were also recorded during the entire procedure. Results: After the VG intervention, psychometric measures such as anxiety levels, impulsivity and novelty seeking decreased. Regarding the neuropsychological measures, impulsivity levels (measured with the CPT-II) progressively decreased throughout the intervention, and an improvement in decision making capacities was observed. Furthermore, the frequency of binges also decreased during and after the VG intervention. Discussion: This case report suggests that using the Playmancer VG to reduce impulsivity prior to CBT may enhance the final results of the treatment for BN. PMID:26236261

Do individuals higher in impulsivity drink more impulsively? A pilot study within a high risk sample of young adults.

PubMed

Stevens, Angela K; Littlefield, Andrew K; Talley, Amelia E; Brown, Jennifer L

2017-02-01

Extant literature has established a strong relation between individual differences in "impulsivity" and alcohol consumption. However, the relation between "impulsivity," intentions-to-drink, and alcohol consumption has remained understudied. As a part of a larger study, 77 participants (60.5% female, 76.3% White, M age=20.8) completed 10days of daily diary reports regarding their intention to use alcohol and alcohol consumption. Hierarchical linear modeling (HLM) was used to estimate within-person relations between intentions-to-drink and subsequent alcohol use. All models were adjusted for participant age, biological sex, and day of the week. Results showed a strong positive association between daily intention to consume alcohol and self-reported alcohol use (β=0.50, p<0.01). Importantly, tests of interactions indicated that individuals higher in impulsivity were not significantly more likely to engage in unplanned drinking. Multilevel mediation analyses indicated significant indirect effects between impulsivity-like constructs, including positive urgency, lack-of-planning, and self-report delay discounting, and reported daily alcohol consumption via higher overall (i.e., between-person) levels of intentions-to-drink; that is, individuals who reported higher levels of these impulsivity-related constructs were more likely to intend to drink across the 10-days and, in turn, consumed more alcohol. Findings from the study suggest that treatment providers could address drinking intentions among individuals higher in impulsivity and work to establish potential replacement behaviors to reduce alcohol consumption in this population. Copyright © 2016 Elsevier Ltd. All rights reserved.

Delay discounting and response disinhibition under acute experimental stress in women with borderline personality disorder and adult attention deficit hyperactivity disorder.

PubMed

Krause-Utz, A; Cackowski, S; Daffner, S; Sobanski, Esther; Plichta, Michael M; Bohus, M; Ende, G; Schmahl, C

2016-11-01

Impulsivity is a core feature of borderline personality disorder (BPD) and attention deficit hyperactivity disorder (ADHD). In BPD, impulsive behavior primarily occurs under acute stress; impulse control deficits under non-stress conditions may be partly related to co-morbid ADHD. We aimed to investigate whether acute experimental stress has an impact on self-reported impulsivity, response inhibition (action withholding, action cancelation) and delay discounting in BPD compared to ADHD. Thirty female BPD patients, 28 female ADHD patients (excluding patients with co-morbid BPD and ADHD), and 30 female healthy controls (HC) completed self-reports and behavioral measures of impulsivity (IMT, assessing action withholding; GoStop, measuring action cancelation, Delay Discounting Task) under baseline conditions and after an experimental stress induction (Mannheim Multicomponent Stress Test). Both patient groups reported higher impulsivity than HC, ADHD reported higher trait impulsivity than BPD. On the IMT, ADHD showed significant action-withholding deficits under both conditions, while BPD performed significantly worse than HC under stress. In BPD but not ADHD and HC, action-withholding deficits (IMT) were significantly increased under stress compared to baseline, while no group/stress effects were found for action cancelation (GoStop). Delay discounting was significantly more pronounced in BPD than in HC (no stress effect was found). In BPD, behavioral deficits in action withholding (but not in action cancelation) appear to be influenced by acute experimental stress. Delay discounting seems to be a general feature of BPD, independent of co-morbid ADHD and acute stress, possibly underlying typical expressions of behavioral impulsivity in the disorder.

Undifferentiated negative affect and impulsivity in borderline personality and depressive disorders: A momentary perspective.

PubMed

Tomko, Rachel L; Lane, Sean P; Pronove, Lisa M; Treloar, Hayley R; Brown, Whitney C; Solhan, Marika B; Wood, Phillip K; Trull, Timothy J

2015-08-01

Individuals with borderline personality disorder (BPD) often report experiencing several negative emotions simultaneously, an indicator of "undifferentiated" negative affect. The current study examined the relationship between undifferentiated negative affect and impulsivity. Participants with a current BPD (n = 67) or depressive disorder (DD; n = 38) diagnosis carried an electronic diary for 28 days, reporting on emotions and impulsivity when randomly prompted (up to 6 times per day). Undifferentiated negative affect was quantified using momentary intraclass correlation coefficients, which indicated how consistently negative emotion items were rated across fear, hostility, and sadness subscales. Undifferentiated negative affect at the occasion-level, day-level, and across 28 days was used to predict occasion-level impulsivity. Multilevel modeling was used to test the hypothesis that undifferentiated negative emotion would be a significant predictor of momentary impulsivity above and beyond levels of overall negative affect. Undifferentiated negative affect at the occasion and day levels were significant predictors of occasion-level impulsivity, but undifferentiated negative affect across the 28-day study period was only marginally significant. Results did not differ depending on BPD or DD status, though individuals with BPD did report significantly greater momentary impulsivity and undifferentiated negative affect. Undifferentiated negative affect may increase risk for impulsivity among individuals with BPD and depressive disorders, and the current data suggest that this process can be relatively immediate as well as cumulative over the course of a day. This research supports the consideration of undifferentiated negative affect as a transdiagnostic construct, but one that may be particularly relevant for those with BPD. (c) 2015 APA, all rights reserved).

Increased impulsive action in rats: effects of morphine in a short and long fixed-delay response inhibition task.

PubMed

Mahoney, Megan K; Silveira, Mason M; Olmstead, Mary C

2013-12-01

Impulsive action is mediated through several neurochemical systems, although it is not clear which role each of these plays in the inability to withhold inappropriate responses. Manipulations of the opioid system alter impulsive action in rodents, although the effects are not consistent across tasks. Previously, we speculated that these discrepancies reflect differences in the cognitive mechanisms that control responding in each task. We investigated whether the effect of morphine, a mu opioid receptor (MOR) agonist, on impulsive action depends on the ability of the subjects to time the interval during which they must inhibit a response. Male Long-Evans rats were trained in a response inhibition (RI) task to withhold responding for sucrose during a 4- or 60-s delay; impulsive action was assessed as increased responding during the delay. The rats were tested following an injection of morphine (0, 1, 3, 6 mg/kg). In a subsequent experiment, the effects of morphine (6 mg/kg) plus the MOR antagonist naloxone (0, 0.3, 1, 3 mg/kg) were investigated. Morphine increased impulsive action, but had different effects in the two conditions: the drug increased the proportion of premature responses as the 4-s interval progressed and produced a general increase in responding across the 60-s interval. Naloxone blocked all morphine-induced effects. The finding that morphine increases impulsive action in a fixed-delay RI task contrasts with our previous evidence which shows no effect in the same task with a variable delay. Thus, MORs disrupt impulsive action only when rats can predict the delay to respond.

Can't stop the craving: the effect of impulsivity on cue-elicited craving for alcohol in heavy and light social drinkers.

PubMed

Papachristou, Harilaos; Nederkoorn, Chantal; Havermans, Remco; van der Horst, Martje; Jansen, Anita

2012-01-01

A robust finding in the alcohol literature is that heavy and alcohol-dependent drinkers show stronger reactions to alcohol-related cues than light drinkers. However, there are individual differences in the degree of cue-elicited craving. Personality factors appear to be involved in cue reactivity and impulsivity is a possible candidate. The aim of the present study was to examine the role of different aspects of impulsivity in heavy drinking and alcohol cue reactivity in social drinkers. Participants were heavy (n = 13) and light (n = 29) social drinkers who were exposed to neutral and alcohol-related stimuli during a single laboratory session. Trait impulsivity, response inhibition, and sensitivity to reward were assessed with the Barratt Impulsiveness Scale (BIS-11), the Stop Signal Task, and the Card-Arranging Reward Responsivity Objective Test, respectively. Heavy drinkers scored higher on trait impulsivity (BIS-11) than light drinkers. In addition, heavy drinkers reported elevated levels of craving for alcohol, but both in light and heavy drinkers, craving increased equally after exposure to alcohol cues. Impulsivity appeared to moderate this relation: heavy drinkers with ineffective response inhibition showed more craving to alcohol cues, compared to heavy drinkers with adequate response inhibition. In light drinkers, response inhibition did not influence craving to alcohol cues. Different aspects of impulsivity are involved in heavy drinking and perhaps motivate alcohol consumption in a variety of ways. Having a deficient response inhibition appears to be a risk factor for heavy drinkers because it is associated with increased craving to alcohol cues.

Undifferentiated Negative Affect and Impulsivity in Borderline Personality and Depressive Disorders: A Momentary Perspective

PubMed Central

Pronove, Lisa M.; Treloar, Hayley R.; Brown, Whitney C.; Solhan, Marika B.; Wood, Phillip K.; Trull, Timothy J.

2015-01-01

Individuals with borderline personality disorder (BPD) often report experiencing several negative emotions simultaneously, an indicator of “undifferentiated” negative affect. The current study examined the relationship between undifferentiated negative affect and impulsivity. Participants with a current BPD (n = 67) or depressive disorder (DD; n = 38) diagnosis carried an electronic diary for 28 days, reporting on emotions and impulsivity when randomly prompted (up to 6 times per day). Undifferentiated negative affect was quantified using momentary intraclass correlation coefficients, which indicated how consistently negative emotion items were rated across fear, hostility, and sadness subscales. Undifferentiated negative affect at the occasion-level, day-level, and across 28 days was used to predict occasion-level impulsivity. Multilevel modeling was used to test the hypothesis that undifferentiated negative emotion would be a significant predictor of momentary impulsivity above and beyond levels of overall negative affect. Undifferentiated negative affect at the occasion and day levels were significant predictors of occasion-level impulsivity, but undifferentiated negative affect across the 28-day study period was only marginally significant. Results did not differ depending on BPD or DD status, though BPD individuals did report significantly greater momentary impulsivity and undifferentiated negative affect. Undifferentiated negative affect may increase risk for impulsivity among individuals with BPD and depressive disorders, and the current data suggest that this process can be relatively immediate as well as cumulative over the course of a day. This research supports the consideration of undifferentiated negative affect as a transdiagnostic construct, but one that may be particularly relevant for those with BPD. PMID:26147324

Neurocognitive responses to a single session of static squats with whole body vibration.

PubMed

Amonette, William E; Boyle, Mandy; Psarakis, Maria B; Barker, Jennifer; Dupler, Terry L; Ott, Summer D

2015-01-01

The purpose of this study was to determine if the head accelerations using a common whole body vibration (WBV) exercise protocol acutely reduced neurocognition in healthy subjects. Second, we investigated differential responses to WBV plates with 2 different delivery mechanisms: vertical and rotational vibrations. Twelve healthy subjects (N = 12) volunteered and completed a baseline (BASE) neurocognitive assessment: the Immediate Postconcussion Assessment and Cognitive Test (ImPACT). Subjects then participated in 3 randomized exercise sessions separated by no more than 2 weeks. The exercise sessions consisted of five 2-minute sets of static hip-width stance squats, with the knees positioned at a 45° angle of flexion. The squats were performed with no vibration (control [CON]), with a vertically vibrating plate (vertical vibration [VV]), and with a rotational vibrating plate (rotational vibration [RV]) set to 30 Hz with 4 mm of peak-to-peak displacement. The ImPACT assessments were completed immediately after each exercise session and the composite score for 5 cognitive domains was analyzed: verbal memory, visual memory, visual motor speed, reaction time, and impulse control. Verbal memory scores were unaffected by exercise with or without vibration (p = 0.40). Likewise, visual memory was not different (p = 0.14) after CON, VV, or RV. Significant differences were detected for visual motor speed (p = 0.006); VV was elevated compared with BASE (p = 0.01). There were no significant differences (p = 0.26) in reaction time or impulse control (p = 0.16) after exercise with or without vibration. In healthy individuals, 10 minutes of 30 Hz, 4-mm peak-to-peak displacement vibration exposure with a 45° angle of knee flexion did not negatively affect neurocognition.

Experimental and simulation study of a Gaseous oxygen/Gaseous hydrogen vortex cooling thrust chamber

NASA Astrophysics Data System (ADS)

Yu, Nanjia; Zhao, Bo; Li, Gongnan; Wang, Jue

2016-01-01

In this paper, RNG k-ε turbulence model and PDF non-premixed combustion model are used to simulate the influence of the diameter of the ring of hydrogen injectors and oxidizer-to-fuel ratio on the specific impulse of the vortex cooling thrust chamber. The simulation results and the experimental tests of a 2000 N Gaseous oxygen/Gaseous hydrogen vortex cooling thrust chamber reveal that the efficiency of the specific impulse improves significantly with increasing of the diameter of the ring of hydrogen injectors. Moreover, the optimum efficiency of the specific impulse is obtained when the oxidizer-to-fuel ratio is near the stoichiometric ratio.

On the performance of piezoelectric harvesters loaded by finite width impulses

NASA Astrophysics Data System (ADS)

Doria, A.; Medè, C.; Desideri, D.; Maschio, A.; Codecasa, L.; Moro, F.

2018-02-01

The response of cantilevered piezoelectric harvesters loaded by finite width impulses of base acceleration is studied analytically in the frequency domain in order to identify the parameters that influence the generated voltage. Experimental tests are then performed on harvesters loaded by hammer impacts. The latter are used to confirm analytical results and to validate a linear finite element (FE) model of a unimorph harvester. The FE model is, in turn, used to extend analytical results to more general harvesters (tapered, inverse tapered, triangular) and to more general impulses (heel strike in human gait). From analytical and numerical results design criteria for improving harvester performance are obtained.

An extension of command shaping methods for controlling residual vibration using frequency sampling

NASA Technical Reports Server (NTRS)

Singer, Neil C.; Seering, Warren P.

1992-01-01

The authors present an extension to the impulse shaping technique for commanding machines to move with reduced residual vibration. The extension, called frequency sampling, is a method for generating constraints that are used to obtain shaping sequences which minimize residual vibration in systems such as robots whose resonant frequencies change during motion. The authors present a review of impulse shaping methods, a development of the proposed extension, and a comparison of results of tests conducted on a simple model of the space shuttle robot arm. Frequency shaping provides a method for minimizing the impulse sequence duration required to give the desired insensitivity.

No Effect of Subthalamic Deep Brain Stimulation on Intertemporal Decision-Making in Parkinson Patients123

PubMed Central

Wojtecki, Lars; Storzer, Lena; Schnitzler, Alfons

2016-01-01

Abstract Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a widely used treatment for the motor symptoms of Parkinson’s disease (PD). DBS or pharmacological treatment is believed to modulate the tendency to, or reverse, impulse control disorders. Several brain areas involved in impulsivity and reward valuation, such as the prefrontal cortex and striatum, are linked to the STN, and activity in these areas might be affected by STN-DBS. To investigate the effect of STN-DBS on one type of impulsive decision-making—delay discounting (i.e., the devaluation of reward with increasing delay until its receipt)—we tested 40 human PD patients receiving STN-DBS treatment and medication for at least 3 months. Patients were pseudo-randomly assigned to one of four groups to test the effects of DBS on/off states as well as medication on/off states on delay discounting. The delay-discounting task consisted of a series of choices among a smaller. sooner or a larger, later monetary reward. Despite considerable effects of DBS on motor performance, patients receiving STN-DBS did not choose more or less impulsively compared with those in the off-DBS group, as well as when controlling for risk attitude. Although null results have to be interpreted with caution, our findings are of significance to other researchers studying the effects of PD treatment on impulsive decision-making, and they are of clinical relevance for determining the therapeutic benefits of using STN-DBS. PMID:27257622

Explosive materials equivalency, test methods and evaluation

NASA Technical Reports Server (NTRS)

Koger, D. M.; Mcintyre, F. L.

1980-01-01

Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

A Nuclear Cryogenic Propulsion Stage for Near-Term Space Missions

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen E.; Adams, Robert B.; Bechtel, Ryan D.; Borowski, Stanley K.;

The multi-modal responses of a physical head model subjected to various blast exposure conditions

NASA Astrophysics Data System (ADS)

Ouellet, S.; Philippens, M.

2018-01-01

The local and global biomechanical response of the body to a blast wave is the first step of a sequence that leads to the development of stresses and strains which can exceed the tolerance of brain tissue. These stresses and strains may then lead to neuro-physical changes in the brain and contribute to initiate a cascade of events leading to injury. The specific biomechanical pathways by which the blast energy is transmitted through the head structure are, however, not clearly understood. Multiple transmission mechanisms have been proposed to explain the generation of brain stresses following the impingement of a blast wave on the head. With the use of a physical head model, the work presented here aims at demonstrating that the proposed transmission mechanisms are not mutually exclusive. They are part of a continuum of head responses where, depending on the exposure conditions, a given mechanism may or may not dominate. This article presents the joint analysis of previous blast test results generated with the brain injury protection evaluation device (BIPED) headform under four significantly different exposure conditions. The focus of the analysis is to demonstrate how the nature of the recorded response is highly dependent on the exposure characteristics and consequently, on the method used to reproduce blast exposure in a laboratory environment. The timing and magnitude of the variations in intra-cranial pressures (ICP) were analysed relative to the external pressure field in order to better understand the wave dynamics occurring within the brain structure of the headform. ICP waveforms were also analysed in terms of their energy spectral density to better identify the energy partitioning between the different modes of response. It is shown that the BIPED response is multi-modal and that the energy partitioning between its different modes of response is greatly influenced by exposure characteristics such as external peak overpressure, impulse, blast wave structure, and direction of propagation. Convincing evidence of stresses generated from local skull deformation is presented along with evidence of stress transmission through relative brain-to-skull motion. These findings suggest that research aimed at defining exposure thresholds should not focus on a single stress transmission mechanism or use experimental designs unrepresentative of realistic blast loading conditions that may favour a given mechanism over another.

Effects of RTV coating on the electrical performance of polymer insulator under lightning impulse voltage condition.

PubMed

Jamaludin, Farah Adilah; Ab-Kadir, Mohd Zainal Abidin; Izadi, Mahdi; Azis, Norhafiz; Jasni, Jasronita; Abd-Rahman, Muhammad Syahmi

2017-01-01

Located near the equator, Malaysia is a country with one of the highest lightning densities in the world. Lightning contributes to 70% of the power outages in Malaysia and affects power equipment, automated network systems, causes data losses and monetary losses in the nation. Therefore, consideration of insulator evaluation under lightning impulses can be crucial to evaluate and attempt to overcome this issue. This paper presents a new approach to increase the electrical performance of polymer insulators using a Room Temperature Vulcanisation (RTV) coating. The evaluation involves three different settings of polymer insulator, namely uncoated, RTV type 1, and RTV type 2 upper surface coatings. All the insulators were tested under three different conditions as dry, clean wet and salty under different impulse polarities using the even-rising test method. The voltage breakdown for each test was recorded. From the experiment, it was found that the effectiveness of the RTV coating application became apparent when tested under salty or polluted conditions. It increased the voltage withstand capabilities of the polymer insulator up to 50% from the basic uncoated insulator. Under dry and clean conditions, the RTV coating provided just a slight increase of the breakdown voltage. The increase in voltage breakdown capability decreased the probability of surface discharge and dry band arcing that could cause degradation of the polymeric material housing. The RTV type 1 coating was found to be more effective when performing under a lightning impulse. The findings might help the utility companies improve the performance of their insulators in order to increase power system reliability.

Effects of RTV coating on the electrical performance of polymer insulator under lightning impulse voltage condition

PubMed Central

Jamaludin, Farah Adilah; Ab-Kadir, Mohd Zainal Abidin; Izadi, Mahdi; Azis, Norhafiz; Jasni, Jasronita; Abd-Rahman, Muhammad Syahmi

2017-01-01

Located near the equator, Malaysia is a country with one of the highest lightning densities in the world. Lightning contributes to 70% of the power outages in Malaysia and affects power equipment, automated network systems, causes data losses and monetary losses in the nation. Therefore, consideration of insulator evaluation under lightning impulses can be crucial to evaluate and attempt to overcome this issue. This paper presents a new approach to increase the electrical performance of polymer insulators using a Room Temperature Vulcanisation (RTV) coating. The evaluation involves three different settings of polymer insulator, namely uncoated, RTV type 1, and RTV type 2 upper surface coatings. All the insulators were tested under three different conditions as dry, clean wet and salty under different impulse polarities using the even-rising test method. The voltage breakdown for each test was recorded. From the experiment, it was found that the effectiveness of the RTV coating application became apparent when tested under salty or polluted conditions. It increased the voltage withstand capabilities of the polymer insulator up to 50% from the basic uncoated insulator. Under dry and clean conditions, the RTV coating provided just a slight increase of the breakdown voltage. The increase in voltage breakdown capability decreased the probability of surface discharge and dry band arcing that could cause degradation of the polymeric material housing. The RTV type 1 coating was found to be more effective when performing under a lightning impulse. The findings might help the utility companies improve the performance of their insulators in order to increase power system reliability. PMID:29136025

Structure-based modeling of head-related transfer functions towards interactive customization of binaural sound systems

NASA Astrophysics Data System (ADS)

Gupta, Navarun

2003-10-01

One of the most popular techniques for creating spatialized virtual sounds is based on the use of Head-Related Transfer Functions (HRTFs). HRTFs are signal processing models that represent the modifications undergone by the acoustic signal as it travels from a sound source to each of the listener's eardrums. These modifications are due to the interaction of the acoustic waves with the listener's torso, shoulders, head and pinnae, or outer ears. As such, HRTFs are somewhat different for each listener. For a listener to perceive synthesized 3-D sound cues correctly, the synthesized cues must be similar to the listener's own HRTFs. One can measure individual HRTFs using specialized recording systems, however, these systems are prohibitively expensive and restrict the portability of the 3-D sound system. HRTF-based systems also face several computational challenges. This dissertation presents an alternative method for the synthesis of binaural spatialized sounds. The sound entering the pinna undergoes several reflective, diffractive and resonant phenomena, which determine the HRTF. Using signal processing tools, such as Prony's signal modeling method, an appropriate set of time delays and a resonant frequency were used to approximate the measured Head-Related Impulse Responses (HRIRs). Statistical analysis was used to find out empirical equations describing how the reflections and resonances are determined by the shape and size of the pinna features obtained from 3D images of 15 experimental subjects modeled in the project. These equations were used to yield "Model HRTFs" that can create elevation effects. Listening tests conducted on 10 subjects show that these model HRTFs are 5% more effective than generic HRTFs when it comes to localizing sounds in the frontal plane. The number of reversals (perception of sound source above the horizontal plane when actually it is below the plane and vice versa) was also reduced by 5.7%, showing the perceptual effectiveness of this approach. The model is simple, yet versatile because it relies on easy to measure parameters to create an individualized HRTF. This low-order parameterized model also reduces the computational and storage demands, while maintaining a sufficient number of perceptually relevant spectral cues.

49 CFR 572.162 - Head assembly and test procedure.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Head assembly and test procedure. 572.162 Section... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.162 Head assembly and test procedure. The head assembly is assembled and tested as specified in 49 CFR 572.122 (Subpart N). ...

49 CFR 572.162 - Head assembly and test procedure.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Head assembly and test procedure. 572.162 Section... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.162 Head assembly and test procedure. The head assembly is assembled and tested as specified in 49 CFR 572.122 (Subpart N). ...

49 CFR 572.162 - Head assembly and test procedure.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Head assembly and test procedure. 572.162 Section... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.162 Head assembly and test procedure. The head assembly is assembled and tested as specified in 49 CFR 572.122 (Subpart N). ...

49 CFR 572.162 - Head assembly and test procedure.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 7 2011-10-01 2011-10-01 false Head assembly and test procedure. 572.162 Section... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.162 Head assembly and test procedure. The head assembly is assembled and tested as specified in 49 CFR 572.122 (Subpart N). ...

49 CFR 572.162 - Head assembly and test procedure.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Head assembly and test procedure. 572.162 Section... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.162 Head assembly and test procedure. The head assembly is assembled and tested as specified in 49 CFR 572.122 (Subpart N). ...

Effect of work intensity on time delay in mediation of ventilation by arterial carbon dioxide during recovery from impulse exercise.

PubMed

Afroundeh, R; Arimitsu, T; Yamanaka, R; Lian, C S; Shirakawa, K; Yunoki, T; Yano, T

2014-01-01

Time delay in the mediation of ventilation (V(.)E) by arterial CO(2) pressure (PaCO(2)) was studied during recovery from short impulse-like exercises with different work loads of recovery. Subjects performed two tests including 10-s impulse like exercise with work load of 200 watts and 15-min recovery with 25 watts in test one and 50 watts in test two. V(.)E, end tidal CO(2) pressure (PETCO(2)) and heart rate (HR) were measured continuously during rest, warming up, exercise and recovery. PaCO(2) was estimated from PETCO(2) and tidal volume (V(T)). Results showed that predicted arterial CO(2) pressure (PaCO(2 pre)) increased during recovery in both tests. In both tests, V(.)E increased and peaked at the end of exercise. V(.)E decreased in the first few seconds of recovery but started to increase again. The highest correlation coefficient between PaCO(2 pre) and V(.)E was obtained in the time delay of 7 s (r=0.854) in test one and in time delays of 6 s (r=0.451) and 31 s (r=0.567) in test two. HR was significantly higher in test two than in test one. These results indicate that PaCO(2 pre) drives V(.)E with a time delay and that higher work intensity induces a shorter time delay.

Summary of Altitude Pulse Testing of a 100-lbf L02/LCH4 Reaction Control Engine

NASA Technical Reports Server (NTRS)

Marshall, William M.; Kleinhenz, Julie E.

2011-01-01

Recently, liquid oxygen-liquid methane (LO2/LCH4) has been considered as a potential "green" propellant alternative for future exploration missions. The Propulsion and Cryogenic Advanced Development (PCAD) project has been tasked by NASA to develop this propulsion combination to enable safe and cost effective exploration missions. To date, limited experience with such combinations exist, and as a result a comprehensive test program is critical to demonstrating the viability of implementing such a system. The NASA Glenn Research Center has conducted a test program of a 100-lbf (445-N) reaction control engine (RCE) at the center s Altitude Combustion Stand (ACS), focusing on altitude testing over a wide variety of operational conditions. The ACS facility includes a unique propellant conditioning feed system (PCFS) which allows precise control of propellant inlet conditions to the engine. Engine performance as a result of these inlet conditions was examined extensively during the test program. This paper is a companion to the previous specific impulse testing paper, and discusses the pulsed mode operation portion of testing, with a focus on minimum impulse bit (I-bit) and repeatable pulse performance. The engine successfully demonstrated target minimum impulse bit performance at all conditions, as well as successful demonstration of repeatable pulse widths. Some anomalous conditions experienced during testing are also discussed, including a double pulse phenomenon which was not noted in previous test programs for this engine.

Working Memory and Impulsivity Predict Marijuana-Related Problems Among Frequent Users

PubMed Central

Day, Anne M.; Metrik, Jane; Spillane, Nichea S.; Kahler, Christopher W.

2012-01-01

Background Although marijuana is the most commonly used illicit substance in the US, only a small portion of users go on to develop dependence, suggesting that there are substantial individual differences in vulnerability to marijuana-related problems among users. Deficits in working memory and high trait impulsivity are two factors that may place marijuana users at increased risk for experiencing related problems. Methods Using baseline data from an experimental study that recruited 104 frequent marijuana users (M=71.86% of prior 60 days, SD=22%), we examined the associations of working memory and trait impulsivity with marijuana-related problems. Results Lower working memory, as measured by Trail Making Test B, but not short-term memory capacity, predicted more marijuana-related problems. Higher trait impulsivity scores were independently associated with greater number of problems. Conclusions Results suggest that marijuana users with reduced executive cognitive ability are more susceptible to developing problems related to their use. Trait impulsivity and executive working memory appear to be independent risk factors for experiencing marijuana-related problems. PMID:23312340

Penrose junction conditions extended: Impulsive waves with gyratons

NASA Astrophysics Data System (ADS)

Podolský, J.; Švarc, R.; Steinbauer, R.; Sämann, C.

2017-09-01

We generalize the classical junction conditions for constructing impulsive gravitational waves by the Penrose "cut and paste" method. Specifically, we study nonexpanding impulses which propagate in spaces of constant curvature with any value of the cosmological constant (that is, Minkowski, de Sitter, or anti-de Sitter universes) when additional off-diagonal metric components are present. Such components encode a possible angular momentum of the ultrarelativistic source of the impulsive wave—the so-called gyraton. We explicitly derive and analyze a specific transformation that relates the distributional form of the metric to a new form which is (Lipschitz) continuous. Such a transformation automatically implies an extended version of the Penrose junction conditions. It turns out that the conditions for identifying points of the background spacetime across the impulse are the same as in the original Penrose cut and paste construction, but their derivatives now directly represent the influence of the gyraton on the axial motion of test particles. Our results apply both for vacuum and nonvacuum solutions of Einstein's field equations and can also be extended to other theories of gravity.

Investigation of helicopter rotor blade/wake interactive impulsive noise

NASA Technical Reports Server (NTRS)

Miley, S. J.; Hall, G. F.; Vonlavante, E.

1987-01-01

An analysis of the Tip Aerodynamic/Aeroacoustic Test (TAAT) data was performed to identify possible aerodynamic sources of blade/vortex interaction (BVI) impulsive noise. The identification is based on correlation of measured blade pressure time histories with predicted blade/vortex intersections for the flight condition(s) where impulsive noise was detected. Due to the location of the recording microphones, only noise signatures associated with the advancing blade were available, and the analysis was accordingly restricted to the first and second azimuthal quadrants. The results show that the blade tip region is operating transonically in the azimuthal range where previous BVI experiments indicated the impulsive noise to be. No individual blade/vortex encounter is identifiable in the pressure data; however, there is indication of multiple intersections in the roll-up region which could be the origin of the noise. Discrete blade/vortex encounters are indicated in the second quadrant; however, if impulsive noise were produced here, the directivity pattern would be such that it was not recorded by the microphones. It is demonstrated that the TAAT data base is a valuable resource in the investigation of rotor aerodynamic/aeroacoustic behavior.

Does Drinking to Cope Explain Links Between Emotion-Driven Impulse Control Difficulties and Hazardous Drinking? A Longitudinal Test

PubMed Central

Watkins, Laura E.; Franz, Molly R.; DiLillo, David; Gratz, Kim L.; Messman-Moore, Terri L.

2016-01-01

Difficulty controlling impulsive behaviors when experiencing negative emotions is a prominent risk factor for hazardous alcohol use, and prior research suggests that drinking to cope may mediate this association. The present study examines this possibility prospectively in a sample of 490 young adult women between the ages of 18 and 25. Participants completed measures of emotion-driven impulse control difficulties, drinking to cope, and hazardous alcohol use at six time points over the course of approximately 20 months (i.e., one assessment every four months). Multilevel structural equation modeling revealed that drinking to cope fully mediated the relationship between emotion-driven impulse control difficulties and hazardous alcohol use when examining these relationships between individuals and partially mediated this relation when examining these relationships within individuals. These findings suggest that drinking to cope is a key mechanism in the relationship between emotion-driven impulse control difficulties and hazardous drinking. Results highlight the importance of targeting both emotion dysregulation and drinking to cope when treating young women for alcohol use problems. PMID:26502334

Vertigo and dizziness in children.

PubMed

Jahn, Klaus; Langhagen, Thyra; Heinen, Florian

2015-02-01

Vertigo and dizziness occur with considerable frequency in childhood and adolescence. Most causes are benign and treatable. This review aims to make physicians more alert to the frequent causes of dizziness in the young. Epidemiological data confirm that migraine-related syndromes are the most common cause of vertigo in children. Vestibular migraine and benign paroxysmal vertigo have now been defined by the International Classification of Headache Disorders. About half of the adolescents with vertigo and dizziness show psychiatric comorbidity and somatization. Vestibular paroxysmia has been described as a new entity in children that can be treated with low doses of carbamazepine. To assess vestibular deficits, video head impulses (for the semicircular canals) and vestibular-evoked myogenic potentials (for the otoliths) are increasingly being used. Pediatricians and neuro-otologists should be aware of the full spectrum of causes of vertigo and dizziness in children and adolescents. Vestibular function can reliably be tested nowadays. Although treatment for the common migraine-related syndromes can be done in analogy to the treatment of migraine in general, specific approaches are required for somatoform vertigo, the most frequent diagnosis in adolescent girls.

Performance and lifetime assessment of MPD arc thruster technology

NASA Technical Reports Server (NTRS)

Sovey, James S.; Mantenieks, Maris A.

1988-01-01

A summary of performance and lifetime characteristics of pulsed and steady-state magnetoplasmadynamic (MPD) thrusters is presented. The technical focus is on cargo vehicle propulsion for exploration-class missions to the Moon and Mars. Relatively high MPD thruster efficiencies of 0.43 and 0.69 have been reported at about 5000 s specific impulse using hydrogen and lithium, respectively. Efficiencies of 0.10 to 0.35 in the 1000 to 4500 s specific impulse range have been obtained with other propellants (e.g., Ar, NH3, N2). Thermal efficiency data in excess of 0.80 at MW power levels using pulsed thrusters indicate the potential of high MPD thruster performance. Extended tests of pulsed and steady-state MPD thrusters yield total impulses at least two to three orders of magnitude below that necessary for cargo vehicle propulsion. Performance tests and diagnostics for life-limiting mechanisms of megawatt-class thrusters will require high fidelity test stands which handle in excess of 10 kA and a vacuum facility whose operational pressure is less than 3 x 10 to the -4 torr.

'Roid rage in rats? Testosterone effects on aggressive motivation, impulsivity and tyrosine hydroxylase.

PubMed

Wood, Ruth I; Armstrong, Abigail; Fridkin, Vlad; Shah, Vivek; Najafi, Allison; Jakowec, Michael

2013-02-17

In humans and animals, anabolic-androgenic steroids (AAS) increase aggression, but the underlying behavioral mechanisms are unclear. AAS may increase the motivation to fight. Alternatively, AAS may increase impulsive behavior, consistent with the popular image of 'roid rage. To test this, adolescent male rats were treated chronically with testosterone (7.5mg/kg) or vehicle and tested for aggressive motivation and impulsivity. Rats were trained to respond on a nose-poke on a 10 min fixed-interval schedule for the opportunity to fight in their home cage with an unfamiliar rat. Although testosterone increased aggression (6.3±1.3 fights/5 min vs 2.4±0.8 for controls, p<0.05), there was no difference in operant responding (28.4±1.6 nose-pokes/10 min for testosterone, 32.4±7.0 for vehicle). This suggests that testosterone does not enhance motivation for aggression. To test for impulsivity, rats were trained to respond for food in a delay-discounting procedure. In an operant chamber, one lever delivered one food pellet immediately, the other lever gave 4 pellets after a delay (0, 15, 30 or 45 s). In testosterone- and vehicle-treated rats, body weights and food intake did not differ. However, testosterone-treated rats chose the larger, delayed reward more often (4.5±0.7 times in 10 trials with 45 s delay) than vehicle controls (2.5±0.5 times, p<0.05), consistent with a reduction in impulsive choice. Thus, although chronic high-dose testosterone enhances aggression, this does not include an increase in impulsive behavior or motivation to fight. This is further supported by measurement of tyrosine hydroxylase (TH) by Western immunoblot analysis in brain regions important for motivation (nucleus accumbens, Acb) and executive function (medial prefrontal cortex, PFC). There were no differences in TH between testosterone- and vehicle-treated rats in Acb or PFC. However, testosterone significantly reduced TH (to 76.9±3.1% of controls, p<0.05) in the caudate-putamen, a brain area important for behavioral inhibition, motor control and habit learning. Copyright © 2013 Elsevier Inc. All rights reserved.

‘Roid rage in rats? Testosterone effects on aggressive motivation, impulsivity and tyrosine hydroxylase

PubMed Central

Wood, Ruth I.; Armstrong, Abigail; Fridkin, Vlad; Shah, Vivek; Najafi, Allison; Jakowec, Michael

2013-01-01

In humans and animals, anabolic-androgenic steroids (AAS) increase aggression, but the underlying behavioral mechanisms are unclear. AAS may increase the motivation to fight. Alternatively, AAS may increase impulsive behavior, consistent with the popular image of ‘roid rage. To test this, adolescent male rats were treated chronically with testosterone (7.5 mg/kg) or vehicle and tested for aggressive motivation and impulsivity. Rats were trained to respond on a nose-poke on a 10 min fixed-interval schedule for the opportunity to fight in their home cage with an unfamiliar rat. Although testosterone increased aggression (6.3±1.3 fights/5 min vs 2.4±0.8 for controls, p<0.05), there was no difference in operant responding (28.4±1.6 nose-pokes/ 10 min for testosterone, 32.4±7.0 for vehicle). This suggests that testosterone does not enhance motivation for aggression. To test for impulsivity, rats were trained to respond for food in a delay-discounting procedure. In an operant chamber, one lever delivered one food pellet immediately, the other lever gave 4 pellets after a delay (0, 15, 30 or 45 s). In testosterone- and vehicle-treated rats, body weights and food intake did not differ. However, testosterone-treated rats chose the larger, delayed reward more often (4.5±0.7 times in 10 trials with 45 s delay) than vehicle controls (2.5±0.5 times, p<0.05), consistent with a reduction in impulsive choice. Thus, although chronic high-dose testosterone enhances aggression, this does not include an increase in impulsive behavior or motivation to fight. This is further supported by measurement of tyrosine hydroxylase (TH) by Western immunoblot analysis in brain regions important for motivation (nucleus accumbens, Acb) and executive function (medial prefrontal cortex, PFC). There were no differences in TH between testosterone- and vehicle-treated rats in Acb or PFC. However, testosterone significantly reduced TH (to 76.9±3.1% of controls, p<0.05) in the caudate-putamen, a brain area important for behavioral inhibition, motor control and habit learning. PMID:23266798

Applied-field MPD thruster geometry effects

NASA Technical Reports Server (NTRS)

Myers, Roger M.

1991-01-01

Eight MPD thruster configurations were used to study the effects of applied field strength, propellant, and facility pressure on thruster performance. Vacuum facility background pressures higher than approx. 0.12 Pa were found to greatly influence thruster performance and electrode power deposition. Thrust efficiency and specific impulse increased monotonically with increasing applied field strength. Both cathode and anode radii fundamentally influenced the efficiency specific impulse relationship, while their lengths influence only the magnitude of the applied magnetic field required to reach a given performance level. At a given specific impulse, large electrode radii result in lower efficiencies for the operating conditions studied. For all test conditions, anode power deposition was the largest efficiency loss, and represented between 50 and 80 pct. of the input power. The fraction of the input power deposited into the anode decreased with increasing applied field and anode radii. The highest performance measured, 20 pct. efficiency at 3700 seconds specific impulse, was obtained using hydrogen propellant.

Transient airload computer analysis for simulating wind induced impulsive noise conditions of a hovering helicopter rotor

NASA Technical Reports Server (NTRS)

Hall, G. F.

1975-01-01

A numerical analysis was developed to determine the airloads on helicopter rotors operating under near-hovering flight conditions capable of producing impulsive noise. A computer program was written in which the solutions for the rotor tip vortex geometry, inflow, aeroelastic response, and airloads are solved in a coupled manner at sequential time steps, with or without the influence of an imposed steady ambient wind or transient gust. The program was developed for future applications in which predicted airloads would be incorporated in an acoustics analysis to attempt to predict and analyze impulsive noise (blade slap). The analysis was applied to a hovering full-scale rotor for which impulsive noise was recorded in the presence of ambient wind. The predicted tip vortex coordinates are in reasonable agreement with the test data, and the blade airload solutions converged to a periodic behavior for an imposed steady ambient wind conditions.

Angular distributions of plasma edge velocity and integrated intensity: Update on specific impulse for Ablative Laser Propulsion

NASA Astrophysics Data System (ADS)

Lin, Jun; Pakhomov, Andrew V.

2005-04-01

This work concludes our discussion of the image processing technique developed earlier for determination of specific impulse (Isp) for Ablative Laser Propulsion (ALP). The plasma plumes are recorded with a time-resolved intensified charge-coupled device (ICCD) camera. The plasma was formed in vacuum (˜ 3×10-3 Torr) by focusing output pulses of a laser system (100-ps pulsewidth at 532 nm wavelength and ˜35 mJ energy) on surfaces of C (graphite), Al, Si, Fe, Cu, Zn, Sn, and Pb elements. Angular profiles for integrated intensity and plasma expansion velocity were determined for the tested elements. Such profiles were used further for assessment of specific impulse. Specific impulses derived from angular distributions of plasma expansion velocity and integral intensity appeared in excellent agreement with the data derived earlier from force measurements.

Impulse processing: A dynamical systems model of incremental eye movements in the visual world paradigm

PubMed Central

Kukona, Anuenue; Tabor, Whitney

2011-01-01

The visual world paradigm presents listeners with a challenging problem: they must integrate two disparate signals, the spoken language and the visual context, in support of action (e.g., complex movements of the eyes across a scene). We present Impulse Processing, a dynamical systems approach to incremental eye movements in the visual world that suggests a framework for integrating language, vision, and action generally. Our approach assumes that impulses driven by the language and the visual context impinge minutely on a dynamical landscape of attractors corresponding to the potential eye-movement behaviors of the system. We test three unique predictions of our approach in an empirical study in the visual world paradigm, and describe an implementation in an artificial neural network. We discuss the Impulse Processing framework in relation to other models of the visual world paradigm. PMID:21609355

Student’s rigorous mathematical thinking based on cognitive style

NASA Astrophysics Data System (ADS)

Fitriyani, H.; Khasanah, U.

2017-12-01

The purpose of this research was to determine the rigorous mathematical thinking (RMT) of mathematics education students in solving math problems in terms of reflective and impulsive cognitive styles. The research used descriptive qualitative approach. Subjects in this research were 4 students of the reflective and impulsive cognitive style which was each consisting male and female subjects. Data collection techniques used problem-solving test and interview. Analysis of research data used Miles and Huberman model that was reduction of data, presentation of data, and conclusion. The results showed that impulsive male subjects used three levels of the cognitive function required for RMT that were qualitative thinking, quantitative thinking with precision, and relational thinking completely while the other three subjects were only able to use cognitive function at qualitative thinking level of RMT. Therefore the subject of impulsive male has a better RMT ability than the other three research subjects.