Changes in cochlear function related to acoustic stimulation of cervical vestibular evoked myogenic potential stimulation.

PubMed

Strömberg, Anna-Karin; Olofsson, Åke; Westin, Magnus; Duan, Maoli; Stenfelt, Stefan

2016-10-01

Evaluation of cervical evoked myogenic potentials (c-VEMP) is commonly applied in clinical investigations of patients with suspected neurotological symptoms. Short intense acoustic stimulation of peak levels close to 130 dB SPL is required to elicit the responses. A recent publication on bilateral significant sensorineural hearing loss related to extensive VEMP stimulation motivates evaluations of immediate effects on hearing acuity related to the intense acoustic stimulation required to elicit c-VEMP responses. The aim of the current study was to investigate changes in DPOAE-levels and hearing thresholds in relation to c-VEMP testing in humans. More specifically, the current focus is on immediate changes in hearing thresholds and changes in DPOAE-levels at frequencies 0.5 octaves above the acoustic stimulation when applying shorter tone bursts than previously used. Hearing acuity before and immediately after exposure to c-VEMP stimulation was examined in 24 patients with normal hearing referred for neurotologic testing. The stimulation consisted of 192 tonebursts of 6 ms and was presented at 500 Hz and 130 dB peSPL. Békésy thresholds at 0.125-8 kHz and DPOAE I/O growth functions with stimulation at 0.75 and 3 kHz were used to assess c-VEMP related changes in hearing status. No significant deterioration in Békésy thresholds was detected. Significant reduction in DPOAE levels at 0.75 (0.5-1.35 dB) and 3 kHz (1.6-2.1 dB) was observed after c-VEMP stimulation without concomitant changes in cochlear compression. The results indicated that there was no immediate audiometric loss related to c-VEMP stimulation in the current group of patients. The significant reduction of DPOAE levels at a wider frequency range than previously described after the c-VEMP test could be related to the stimulation with shorter tone bursts. The results show that c-VEMP stimulation causes reduction in DPOAE-levels at several frequencies that corresponds to half the reductions in

Chirp-modulated visual evoked potential as a generalization of steady state visual evoked potential

NASA Astrophysics Data System (ADS)

Tu, Tao; Xin, Yi; Gao, Xiaorong; Gao, Shangkai

2012-02-01

Visual evoked potentials (VEPs) are of great concern in cognitive and clinical neuroscience as well as in the recent research field of brain-computer interfaces (BCIs). In this study, a chirp-modulated stimulation was employed to serve as a novel type of visual stimulus. Based on our empirical study, the chirp stimuli visual evoked potential (Chirp-VEP) preserved frequency features of the chirp stimulus analogous to the steady state evoked potential (SSVEP), and therefore it can be regarded as a generalization of SSVEP. Specifically, we first investigated the characteristics of the Chirp-VEP in the time-frequency domain and the fractional domain via fractional Fourier transform. We also proposed a group delay technique to derive the apparent latency from Chirp-VEP. Results on EEG data showed that our approach outperformed the traditional SSVEP-based method in efficiency and ease of apparent latency estimation. For the recruited six subjects, the average apparent latencies ranged from 100 to 130 ms. Finally, we implemented a BCI system with six targets to validate the feasibility of Chirp-VEP as a potential candidate in the field of BCIs.

SOMATOSENSORY EVOKED POTENTIALS

EPA Science Inventory

Somatosensory evoked potentials (SEPs) have been used by neuroscientists for many years. The versatility of the method is attested to be the differing purposes to which it has been applied. Initially, SEPs were used to uncover basic principles of sensory processing. A casual glan...

Transesophageal versus transcranial motor evoked potentials to monitor spinal cord ischemia.

PubMed

Tsuda, Kazumasa; Shiiya, Norihiko; Takahashi, Daisuke; Ohkura, Kazuhiro; Yamashita, Katsushi; Kando, Yumi; Arai, Yoshifumi

2016-02-01

We have previously reported that transesophageal motor evoked potential is feasible and more stable than transcranial motor evoked potential. This study aimed to investigate the efficacy of transesophageal motor evoked potential to monitor spinal cord ischemia. Transesophageal and transcranial motor evoked potentials were recorded in 13 anesthetized dogs at the bilateral forelimbs, anal sphincters, and hindlimbs. Spinal cord ischemia was induced by aortic balloon occlusion at the 8th to 10th thoracic vertebra level. In the 12 animals with motor evoked potential disappearance, occlusion was maintained for 10 minutes (n = 6) or 40 minutes (n = 6) after motor evoked potential disappearance. Neurologic function was evaluated by Tarlov score at 24 and 48 hours postoperatively. Time to disappearance of bilateral motor evoked potentials was quicker in transesophageal motor evoked potentials than in transcranial motor evoked potentials at anal sphincters (6.9 ± 3.1 minutes vs 8.3 ± 3.4 minutes, P = .02) and hindlimbs (5.7 ± 1.9 minutes vs 7.1 ± 2.7 minutes, P = .008). Hindlimb function was normal in all dogs in the 10-minute occlusion group, and motor evoked potentials recovery (>75% on both sides) after reperfusion was quicker in transesophageal motor evoked potentials than transcranial motor evoked potentials at hindlimbs (14.8 ± 5.6 minutes vs 24.7 ± 8.2 minutes, P = .001). At anal sphincters, transesophageal motor evoked potentials always reappeared (>25%), but transcranial motor evoked potentials did not in 3 of 6 dogs. In the 40-minute occlusion group, hindlimb motor evoked potentials did not reappear in 4 dogs with paraplegia. Among the 2 remaining dogs, 1 with paraparesis (Tarlov 3) showed delayed recovery (>75%) of hindlimb motor evoked potentials without reappearance of anal sphincter motor evoked potentials. In another dog with spastic paraplegia, transesophageal motor evoked potentials from the hindlimbs remained less than 20%, whereas transcranial motor

[Origin of acoustically evoked short latency negative response in guinea pigs].

PubMed

Huang, Wen-qin; Qin, Huan-hua; Nong, Dong-xiao; Tang, An-zhou; Li, Zhi-mei; Yang, Tian

2011-04-01

To establish a model of acoustically evoked short latency negative response (ASNR) in guinea pigs, a model of profound hearing loss with normal saccular functions, and verify the correlation between ASNR and vestibular evoked myogenic potential (VEMP). Thirty-two healthy guinea pigs were employed in the experiment, which were randomly divided into control group (16 subjects) and deafened group (16 subjects). Each animal experienced auditory and vestibular tests including auditory brainstem response (ABR), VEMP and caloric test. A quick treatment was employed for deafened group consisting of a subcutaneous injection of kanamycin at a dose of 400 mg/kg followed by a jugular vein injection of ethacrynic acid at a dose of 40 mg/kg one hour later. The animals were received ABR, VEMP and caloric test 7 - 10 days following the drug administration. The deafened group was further divided into ASNR group and non-ASNR group, based on the presence of ASNR. In deafened group, five subjects died postoperatively, 11 subjects (22 ears) provided full data, ASNR was elicited in eight ears (36.4%), the threshold was 120 - 130 dB SPL with mean of (124.4 ± 4.96) dB SPL. Its latency range was 1.75 - 2.60 ms with mean of (2.15 ± 0.27) ms. The mean latency of threshold was (2.34 ± 0.18) ms. All eight ASNR ears presented with VEMP. The VEMP threshold, positive and negative potential latencies proved no statistical difference (P > 0.05) between ASNR group and control group. Significant difference was detected between the VEMP presence of ASNR group and non-ASNR group (P = 0.002). There was no statistically significant correlation between VEMP and caloric test neither between ASNR and caloric test in deafened group. This study evoked ASNR in an ototoxicity guinea pig model which has profound hearing loss with normal saccular functions. The presence of ASNR correlated with VEMP, however, not correlated with caloric test, suggesting that ASNR and VEMP are both originated from the saccule.

Acoustically Evoked Different Vibration Pattern Across the Width of the Cochlea Partition

NASA Astrophysics Data System (ADS)

Zha, Dingjun; Chen, Fangyi; Friderberg, Anders; Choudhury, Niloy; Nuttall, Alfred

2011-11-01

Using optical low coherence interferometry, the acoustically evoked vibration patterns of the basilar membrane (BM) and reticular lamina (RL) in the first turn of living guinea pigs were measured as function of the radial location. It was demonstrated that the vibration of the BM varied widely in amplitude, but little in phase across the width of the partition, while the RL had a different vibration pattern compared with the BM.

Contralateral Inhibition of Click- and Chirp-Evoked Human Compound Action Potentials

PubMed Central

Smith, Spencer B.; Lichtenhan, Jeffery T.; Cone, Barbara K.

2017-01-01

Cochlear outer hair cells (OHC) receive direct efferent feedback from the caudal auditory brainstem via the medial olivocochlear (MOC) bundle. This circuit provides the neural substrate for the MOC reflex, which inhibits cochlear amplifier gain and is believed to play a role in listening in noise and protection from acoustic overexposure. The human MOC reflex has been studied extensively using otoacoustic emissions (OAE) paradigms; however, these measurements are insensitive to subsequent “downstream” efferent effects on the neural ensembles that mediate hearing. In this experiment, click- and chirp-evoked auditory nerve compound action potential (CAP) amplitudes were measured electrocochleographically from the human eardrum without and with MOC reflex activation elicited by contralateral broadband noise. We hypothesized that the chirp would be a more optimal stimulus for measuring neural MOC effects because it synchronizes excitation along the entire length of the basilar membrane and thus evokes a more robust CAP than a click at low to moderate stimulus levels. Chirps produced larger CAPs than clicks at all stimulus intensities (50–80 dB ppeSPL). MOC reflex inhibition of CAPs was larger for chirps than clicks at low stimulus levels when quantified both in terms of amplitude reduction and effective attenuation. Effective attenuation was larger for chirp- and click-evoked CAPs than for click-evoked OAEs measured from the same subjects. Our results suggest that the chirp is an optimal stimulus for evoking CAPs at low stimulus intensities and for assessing MOC reflex effects on the auditory nerve. Further, our work supports previous findings that MOC reflex effects at the level of the auditory nerve are underestimated by measures of OAE inhibition. PMID:28420960

Electroretinography and Visual Evoked Potentials in Childhood Brain Tumor Survivors.

PubMed

Pietilä, Sari; Lenko, Hanna L; Oja, Sakari; Koivisto, Anna-Maija; Pietilä, Timo; Mäkipernaa, Anne

2016-07-01

This population-based cross-sectional study evaluates the clinical value of electroretinography and visual evoked potentials in childhood brain tumor survivors. A flash electroretinography and a checkerboard reversal pattern visual evoked potential (or alternatively a flash visual evoked potential) were done for 51 survivors (age 3.8-28.7 years) after a mean follow-up time of 7.6 (1.5-15.1) years. Abnormal electroretinography was obtained in 1 case, bilaterally delayed abnormal visual evoked potentials in 22/51 (43%) cases. Nine of 25 patients with infratentorial tumor location, and altogether 12 out of 31 (39%) patients who did not have tumors involving the visual pathways, had abnormal visual evoked potentials. Abnormal electroretinographies are rarely observed, but abnormal visual evoked potentials are common even without evident anatomic lesions in the visual pathway. Bilateral changes suggest a general and possibly multifactorial toxic/adverse effect on the visual pathway. Electroretinography and visual evoked potential may have clinical and scientific value while evaluating long-term effects of childhood brain tumors and tumor treatment. © The Author(s) 2016.

Auditory fear conditioning modifies steady-state evoked potentials in the rat inferior colliculus.

PubMed

Lockmann, André Luiz Vieira; Mourão, Flávio Afonso Gonçalves; Moraes, Marcio Flávio Dutra

2017-08-01

The rat inferior colliculus (IC) is a major midbrain relay for ascending inputs from the auditory brain stem and has been suggested to play a key role in the processing of aversive sounds. Previous studies have demonstrated that auditory fear conditioning (AFC) potentiates transient responses to brief tones in the IC, but it remains unexplored whether AFC modifies responses to sustained periodic acoustic stimulation-a type of response called the steady-state evoked potential (SSEP). Here we used an amplitude-modulated tone-a 10-kHz tone with a sinusoidal amplitude modulation of 53.7 Hz-as the conditioning stimulus (CS) in an AFC protocol (5 CSs per day in 3 consecutive days) while recording local field potentials (LFPs) from the IC. In the preconditioning session ( day 1 ), the CS elicited prominent 53.7-Hz SSEPs. In the training session ( day 2 ), foot shocks occurred at the end of each CS (paired group) or randomized in the inter-CS interval (unpaired group). In the test session ( day 3 ), SSEPs markedly differed from preconditioning in the paired group: in the first two trials the phase to which the SSEP coupled to the CS amplitude envelope shifted ~90°; in the last two trials the SSEP power and the coherence of SSEP with the CS amplitude envelope increased. LFP power decreased in frequency bands other than 53.7 Hz. In the unpaired group, SSEPs did not change in the test compared with preconditioning. Our results show that AFC causes dissociated changes in the phase and power of SSEP in the IC. NEW & NOTEWORTHY Local field potential oscillations in the inferior colliculus follow the amplitude envelope of an amplitude-modulated tone, originating a neural response called the steady-state evoked potential. We show that auditory fear conditioning of an amplitude-modulated tone modifies two parameters of the steady-state evoked potentials in the inferior colliculus: first the phase to which the evoked oscillation couples to the amplitude-modulated tone shifts

Brainstem Auditory Evoked Potential in HIV-Positive Adults.

PubMed

Matas, Carla Gentile; Samelli, Alessandra Giannella; Angrisani, Rosanna Giaffredo; Magliaro, Fernanda Cristina Leite; Segurado, Aluísio C

2015-10-20

To characterize the findings of brainstem auditory evoked potential in HIV-positive individuals exposed and not exposed to antiretroviral treatment. This research was a cross-sectional, observational, and descriptive study. Forty-five HIV-positive individuals (18 not exposed and 27 exposed to the antiretroviral treatment - research groups I and II, respectively - and 30 control group individuals) were assessed through brainstem auditory evoked potential. There were no significant between-group differences regarding wave latencies. A higher percentage of altered brainstem auditory evoked potential was observed in the HIV-positive groups when compared to the control group. The most common alteration was in the low brainstem. HIV-positive individuals have a higher percentage of altered brainstem auditory evoked potential that suggests central auditory pathway impairment when compared to HIV-negative individuals. There was no significant difference between individuals exposed and not exposed to antiretroviral treatment.

Surgical monitoring with auditory evoked potentials.

PubMed

Lüders, H

1988-07-01

This comprehensive review of surgical monitoring with auditory evoked potentials (AEPs) includes a detailed discussion of techniques used for recording brainstem auditory evoked potentials, direct eight-nerve potentials, and electrocochleograms. The normal waveform of these different potentials is discussed, and the typical patterns of abnormalities seen with different insults to the peripheral or central auditory pathways are presented. The mechanisms most probably responsible for changes in AEPs during surgical procedures are analyzed. A critical analysis is made of what represents a significant change in AEPs. Also considered is the predictive value of intrasurgical changes of AEPs. Finally, attempts are made to determine whether AEPs monitoring can assist the surgeon in the prevention of postsurgical complications.

The effects of click and tone-burst stimulus parameters on the vestibular evoked myogenic potential (VEMP).

PubMed

Akin, Faith Wurm; Murnane, Owen D; Proffitt, Tina M

2003-11-01

Vestibular evoked myogenic potentials (VEMP) are short latency electromyograms (EMG) evoked by high-level acoustic stimuli and recorded from surface electrodes over the tonically contracted sternocleidomastoid (SCM) muscle and are presumed to originate in the saccule. The present experiments examined the effects of click and tone-burst level and stimulus frequency on the latency, amplitude, and threshold of the VEMP in subjects with normal hearing sensitivity and no history of vestibular disease. VEMPs were recorded in all subjects using 100 dB nHL click stimuli. Most subjects had VEMPs present at 500, 750, and 1000 Hz, and few subjects had VEMPs present at 2000 Hz. The response amplitude of the VEMP increased with click and tone-burst level, whereas VEMP latency was not influenced by the stimulus level. The largest tone-burst-evoked VEMPs and lowest thresholds were obtained at 500 and 750 Hz. VEMP latency was independent of stimulus frequency when tone-burst duration was held constant.

Band limited chirp stimulation in vestibular evoked myogenic potentials.

PubMed

Walther, Leif Erik; Cebulla, Mario

2016-10-01

Air conducted vestibular evoked myogenic potentials (VEMP) can be elicited by various low frequency and intense sound stimuli, mainly clicks or short tone bursts (STB). Chirp stimuli are increasingly used in diagnostic audiological evaluations as an effective means to obtain acoustically evoked responses in narrowed or extended frequency ranges. We hypothesized in this study that band limited chirp stimulation, which covers the main sensitivity range of sound sensitive otolithic afferents (around 500 Hz), might be useful for application in cervical and ocular VEMP to air conduction. For this purpose we designed a chirp stimulus ranging 250-1000 Hz (up chirp). The chirp stimulus was delivered with a stimulus intensity of 100 dB nHL in normal subjects (n = 10) and patients with otolith involvement (vestibular neuritis) (n = 6). Amplitudes of the designed chirp ("CW-VEMP-chirp, 250-1000 Hz") were compared with amplitudes of VEMPs evoked by click stimuli (0.1 ms) and a short tone burst (STB, 1-2-1, 8 ms, 500 Hz). CVEMPs and oVEMPs were detectable in 9 of 10 normal individuals. Statistical evaluation in healthy patients revealed significantly larger cVEMP and oVEMP amplitudes for CW-VEMP-chirp (250-1000 Hz) stimuli. CVEMP amplitudes evoked by CW-VEMP-chirp (250-1000 Hz) showed a high stability in comparison with click and STB stimulation. CW-VEMP-chirp (250-1000 Hz) showed abnormal cVEMP and oVEMP amplitudes in patients with vestibular neuritis, with the same properties as click and STB stimulated VEMPs. We conclude that the designed CW-VEMP-chirp (250-1000 Hz) is an effective stimulus which can be further used in VEMP diagnostic. Since a chirp stimulus can be easily varied in its properties, in particular with regard to frequency, this might be a promising tool for further investigations.

Vestibular evoked myogenic potentials (VEMPs) in central neurological disorders.

PubMed

Venhovens, J; Meulstee, J; Verhagen, W I M

2016-01-01

Several types of acoustic stimulation (i.e. tone bursts or clicks), bone-conducted vibration, forehead taps, and galvanic stimulation elicit myogenic potentials. These can be recorded in cervical and ocular muscles, the so called vestibular evoked myogenic potentials (VEMPs). The cervical VEMP (cVEMP) resembles the vestibulo-collic reflex and the responses can be recorded from the ipsilateral sternocleidomastoid muscle. The ocular VEMP resembles the vestibulo-ocular reflex and can be recorded from extra-ocular muscles by a surface electrode beneath the contralateral infraorbital margin. Initially, the literature concerning VEMPs was limited to peripheral vestibular disorders, however, the field of VEMP testing is rapidly expanding, with an increasing focus on central neurological disorders. The current literature concerning VEMP abnormalities in central neurological disorders is critically reviewed, especially regarding the methodological aspects in relation to quality as well as the clinical interpretation of the VEMP results. Suggestions for further research are proposed as well as some clinically useful indications. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

[Evaluation of otoacoustic emissions in relation to brainstem evoked auditory potentials in children].

PubMed

Rado-Triveño, Julia; Alen-Ayca, Jaime

2016-01-01

To determine the validity of the use of acoustic otoacoustic emissions in comparison with the evoked potentials Auditory brainstem examination (PEATC), a study was carried out with 96 children between 0 and 4 years of age that went to Instituto Nacional de Rehabilitación in Lima, Peru. The results show a cut-off point corresponding to 1 in (+): 17.67 in right ear and 16.72 in left ear, and LR (-): 0.25 in ear right and 0.24 in left ear; ROC curve with area under the right ear curve of 0.830 (p<0.001) was obtained and in left ear of 0.829 (p<0.001). According to the results of LR (+) the sensitivity is 76% in the right ear and 65% In the left ear that coincides with the conformation of the ROC curve. In conclusion, acoustic emissions would not represent an alternative sufficiently discriminatory alternative as a screening test in this population.

Comparison of tone burst versus logon stimulation for vestibular evoked myogenic potentials.

PubMed

Ozdek, Ali; Bayır, Omer; Tatar, Emel Cadallı; Korkmaz, Mehmet Hakan

2012-05-01

The following study has been carried out to compare the effectiveness of logon and tone burst acoustic stimulation to elicit vestibular evoked myogenic potential (VEMP) responses. The methods and the subjects include 31 healthy adult volunteers (62 ears) who were enrolled in this study. Two different acoustic stimuli, logon (L-VEMP) and tone burst (T-VEMP), were used to elicit VEMP responses in each subject. Bilateral recordings with simultaneous binaural acoustic stimulations were used during VEMP recordings. During the recording period, the subjects were in supine position with their head elevated. The results observed were that the response rate of p1n1 wave was 91.9% for L-VEMP and 88.7% for T-VEMP. The response rate of n2p2 wave was 80.6% for L-VEMP, and 75.8% for T-VEMP. There were no significant differences between the two groups with respect to the latencies of p1, n1, n2 and p2, p1n1 and n2p2 interval, and p1n1 and n2p2 amplitude. The conclusion was that there was no difference between logon and tone burst stimulation with respect to VEMP response rates and VEMP parameters. Therefore, they are not superior to each other.

Monitoring somatosensory evoked potentials in spinal cord ischemia-reperfusion injury

PubMed Central

Ji, Yiming; Meng, Bin; Yuan, Chenxi; Yang, Huilin; Zou, Jun

2013-01-01

It remains unclear whether spinal cord ischemia-reperfusion injury caused by ischemia and other non-mechanical factors can be monitored by somatosensory evoked potentials. Therefore, we monitored spinal cord ischemia-reperfusion injury in rabbits using somatosensory evoked potential detection technology. The results showed that the somatosensory evoked potential latency was significantly prolonged and the amplitude significantly reduced until it disappeared during the period of spinal cord ischemia. After reperfusion for 30–180 minutes, the amplitude and latency began to gradually recover; at 360 minutes of reperfusion, the latency showed no significant difference compared with the pre-ischemic value, while the somatosensory evoked potential amplitude in-creased, and severe hindlimb motor dysfunctions were detected. Experimental findings suggest that changes in somatosensory evoked potential latency can reflect the degree of spinal cord ischemic injury, while the amplitude variations are indicators of the late spinal cord reperfusion injury, which provide evidence for the assessment of limb motor function and avoid iatrogenic spinal cord injury. PMID:25206629

Normalization of auditory evoked potential and visual evoked potential in patients with idiot savant.

PubMed

Chen, X; Zhang, M; Wang, J; Lou, F; Liang, J

1999-03-01

To investigate the variations of auditory evoked potentials (AEP) and visual evoked potentials (VEP) of patients with idiot savant (IS) syndrome. Both AEP and VEP were recorded from 7 patients with IS syndrome, 21 mentally retarded (MR) children without the syndrome and 21 normally age-matched controls, using a Dantec concerto SEEG-16 BEAM instrument. Both AEP and VEP of MR group showed significantly longer latencies (P1 and P2 latencies of AEP, P < 0.01; N1 and N2 latencies of VEP, P < 0.01/0.05), lower P2 amplitudes (P < 0.01) and higher P3 amplitudes (P < 0.01), as compared with normal controls. But none of above-mentioned changes was found with IS group. Almost all MR patients (90.1%) presented P4 component in both AEP and VEP, which was also in sharp contrast with its incidence in other 2 groups (IS: 14.3%; normal controls: 9.5%). Patients with idiot savant syndrome presented normalized AEP and VEP.

Development of the Acoustically Evoked Behavioral Response in Larval Plainfin Midshipman Fish, Porichthys notatus

PubMed Central

Alderks, Peter W.; Sisneros, Joseph A.

2013-01-01

The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR) in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r2 = 0.92). The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or −15.2 dB re 1 g (z-axis). Lowest AEBR thresholds were 140–150 dB re 1 µPa or −33 to −23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9–2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages. PMID:24340003

Development of the acoustically evoked behavioral response in larval plainfin midshipman fish, Porichthys notatus.

PubMed

Alderks, Peter W; Sisneros, Joseph A

2013-01-01

The ontogeny of hearing in fishes has become a major interest among bioacoustics researchers studying fish behavior and sensory ecology. Most fish begin to detect acoustic stimuli during the larval stage which can be important for navigation, predator avoidance and settlement, however relatively little is known about the hearing capabilities of larval fishes. We characterized the acoustically evoked behavioral response (AEBR) in the plainfin midshipman fish, Porichthys notatus, and used this innate startle-like response to characterize this species' auditory capability during larval development. Age and size of larval midshipman were highly correlated (r(2) = 0.92). The AEBR was first observed in larvae at 1.4 cm TL. At a size ≥ 1.8 cm TL, all larvae responded to a broadband stimulus of 154 dB re1 µPa or -15.2 dB re 1 g (z-axis). Lowest AEBR thresholds were 140-150 dB re 1 µPa or -33 to -23 dB re 1 g for frequencies below 225 Hz. Larval fish with size ranges of 1.9-2.4 cm TL had significantly lower best evoked frequencies than the other tested size groups. We also investigated the development of the lateral line organ and its function in mediating the AEBR. The lateral line organ is likely involved in mediating the AEBR but not necessary to evoke the startle-like response. The midshipman auditory and lateral line systems are functional during early development when the larvae are in the nest and the auditory system appears to have similar tuning characteristics throughout all life history stages.

Vestibular-evoked myogenic potential (VEMP) in the evaluation of schistosomal myeloradiculopathy.

PubMed

Felipe, Lilian; Gonçalves, Denise Utsch; Tavares, Maurício Campelo; Sousa-Pereira, Sílvio Roberto; Antunes, Carlos Maurício de Figueiredo; Lambertucci, José Roberto

2009-10-01

Schistosomal myeloradiculopathy (SMR) is the most severe and disabling form of schistosomiasis. The diagnosis is based on clinical, laboratory, and image data. Vestibular-evoked myogenic potential (VEMP) is a neurophysiologic test that assesses the vestibulospinal pathway through acoustic or galvanic stimuli. The aim of this study was to evaluate cervical spinal abnormalities in patients with SMR. Fifty-two subjects were evaluated, of whom 29 had SMR and 30 did not (normal control). Normal VEMP was observed in all volunteers without SMR. Abnormal VEMP was recorded in 34% of the group with SMR. After treatment, abnormal VEMP was found in 80% of those with persistent neurologic abnormalities. VEMP is a functional test, and the alteration may precede image abnormalities. This procedure may be useful for early diagnosis of schistosomal cervical spinal cord involvement.

Vestibular evoked myogenic potential (Vemp): evaluation of responses in normal subjects.

PubMed

Felipe, Lilian; Santos, Marco Aurélio Rocha; Gonçalves, Denise Utsch

2008-01-01

the Vestibular Evoked Myogenic Potential (Vemp) is formed by myogenic neurophysiologic responses activated by high-intensity sound stimulation. The response is registered through surface electromyography of the cervical muscles during muscle contraction. The acoustic stimuli activate the saccular macula, the vestibular inferior nerve and the pathways related to the vestibule-spinal descendant nerves. to describe Vemp parameters in a normal population. thirty adults, 13 men and 17 women with no otoneurological complaints were selected. The stimuli were 200 tone burst, with a frequency of 1Hz and intensity of 118 dB Na, band-pass filter ranging from 10Hz to 1500Hz. The first potential biphasic P13-N23 wave was analyzed. no significant difference was observed between the sides of stimulation in terms of latency and amplitude. However, a statistically significant difference was found for amplitude between genders. Vemp demonstrated to be a reliable instrument in the clinical assessment of the vestibular function.

Auditory evoked potentials.

PubMed

De Cosmo, G; Aceto, P; Clemente, A; Congedo, E

2004-05-01

Auditory evoked potentials (AEPs) are an electrical manifestation of the brain response to an auditory stimulus. Mid-latency auditory evoked potentials (MLAEPs) and the coherent frequency of the AEP are the most promising for monitoring depth of anaesthesia. MLAEPs show graded changes with increasing anaesthetic concentration over the clinical concentration range. The latencies of Pa and Nb lengthen and their amplitudes reduce. These changes in features of waveform are similar with both inhaled and intravenous anaesthetics. Changes in latency of Pa and Nb waves are highly correlated to a transition from awake to loss of consciousness. MLAEPs recording may also provide information about cerebral processing of the auditory input, probably because it reflects activity in the temporal lobe/primary cortex, sites involved in sounds elaboration and in a complex mechanism of implicit (non declarative) memory processing. The coherent frequency has found to be disrupted by the anaesthetics as well as to be implicated in attentional mechanism. These results support the concept that the AEPs reflects the balance between the arousal effects of surgical stimulation and the depressant effects of anaesthetics. However, AEPs aren't a perfect measure of anaesthesia depth. They can't predict patients movements during surgery and the signal may be affected by muscle artefacts, diathermy and other electrical operating theatre interferences. In conclusion, once reliability of the AEPs recording became proved and the signal acquisition improved it is likely to became a routine feature of clinical anaesthetic practice.

A joint sparse representation-based method for double-trial evoked potentials estimation.

PubMed

Yu, Nannan; Liu, Haikuan; Wang, Xiaoyan; Lu, Hanbing

2013-12-01

In this paper, we present a novel approach to solving an evoked potentials estimating problem. Generally, the evoked potentials in two consecutive trials obtained by repeated identical stimuli of the nerves are extremely similar. In order to trace evoked potentials, we propose a joint sparse representation-based double-trial evoked potentials estimation method, taking full advantage of this similarity. The estimation process is performed in three stages: first, according to the similarity of evoked potentials and the randomness of a spontaneous electroencephalogram, the two consecutive observations of evoked potentials are considered as superpositions of the common component and the unique components; second, making use of their characteristics, the two sparse dictionaries are constructed; and finally, we apply the joint sparse representation method in order to extract the common component of double-trial observations, instead of the evoked potential in each trial. A series of experiments carried out on simulated and human test responses confirmed the superior performance of our method. © 2013 Elsevier Ltd. Published by Elsevier Ltd. All rights reserved.

Transcranial Motor-Evoked Potentials Are More Readily Acquired Than Somatosensory-Evoked Potentials in Children Younger Than 6 Years.

PubMed

McIntyre, Ian W; Francis, Lisa; McAuliffe, John J

2016-01-01

There is a general belief that somatosensory-evoked potentials (SSEPs) are more easily obtained than transcranial motor-evoked potentials (TcMEPs) in children younger than 6 years. We tested this assumption and the assumption that motor-evoked potentials are rarely obtained in children younger than 2 years. The records of all patients who were monitored during surgical procedures between April 1, 2010, and June 30, 2013, were reviewed and those who were younger than 72 months at the time of surgery were identified and analyzed for the rate of obtaining clinically useful SSEPs and motor-evoked potentials. Subgroup analysis was performed by age. A total of 146 patients were identified, 9 had SSEPs without TcMEPs monitored, 117 had both TcMEPs and SSEPs monitored, and the remainder had only electromyographic monitoring. All patients who were to have TcMEPs recorded received a total IV anesthetic. Among the 117 patients who had both SSEPs and TcMEPs monitored, clinically relevant TcMEPs were obtained more frequently than SSEPs (110/117 vs 89/117; χ = 14.82; P = 0.00012). There were significant differences between the rates of obtaining SSEPs and TcMEPs in the 0- to 23-month (P = 0.0038) and 24- to 47-month (P = 0.0056) age groups. Utilization of a double-train stimulation technique facilitated obtaining TcMEPs in the youngest patients. TcMEPs can be obtained more easily than SSEPs in patients younger than 72 months if a permissive anesthetic technique is used. The success rate for obtaining TcMEPs can be further enhanced by the use of a temporal facilitation (double-train) stimulation technique.

Human cerebral potentials evoked by moving dynamic random dot stereograms.

PubMed

Herpers, M J; Caberg, H B; Mol, J M

1981-07-01

In 11 normal healthy human subjects an evoked potential was elicited by moving dynamic random dot stereograms. The random dots were generated by a minicomputer. An average of each of 8 EEG channels of the subjects tested was made. The maximum of the cerebral evoked potentials thus found was localized in the central and parietal region. No response earlier than 130--150 msec after the stimulus could be proved. The influence of fixation, the number of dots provided, an interocular interstimulus interval in the presentation of the dots, and lense accommodation movements on the evoked stereoptic potentials was investigated and discussed. An interocular interstimulus interval (left eye leading) in the presentation of the dots caused an increase in latency of the response much longer than the imposed interstimulus interval itself. It was shown that no accommodation was needed to perceive the depth impression, and to evoke the cerebral response with random dot stereograms. There are indications of an asymmetry between the two hemispheres in the handling of depth perception after 250 msec. The potential distribution of the evoked potentials strongly suggests that they are not generated in the occipital region.

Effect of intrathecal baclofen on evoked pain perception: an evoked potentials and quantitative thermal testing study.

PubMed

Kumru, H; Kofler, M; Flores, M C; Portell, E; Robles, V; Leon, N; Vidal, J

2013-08-01

Somatic antinociceptive effects of baclofen have been demonstrated in animal models. We hypothesized that if enhanced thermal or pain sensitivity is produced by loss of gamma-aminobutyric acid (GABA)-ergic tone in the central nervous system, spinal administration of GABA agonists might be predicted to be effective in thermal and/or pain perception changes and pain-related evoked potentials in candidates for intrathecal baclofen (ITB) treatment. Eleven patients with severe spinal cord injury (SCI) who suffered from severe spasticity were evaluated during a 50-μg ITB bolus test. Warm and heat pain thresholds, evoked heat pain perception, and contact heat-evoked potentials (CHEPs) were determined above SCI level from the right and left sides. Nine age- and gender-matched healthy volunteers undergoing repeat testing without any placebo injection served as control group. In patients, heat pain perception threshold increased, and evoked pain perception and amplitude of CHEPs decreased significantly after ITB bolus application in comparison with baseline (p < 0.005), with no change in warm perception threshold. In controls, no significant changes were observed in repeat testing over time. Our findings indicate that ITB modulates heat pain perception threshold, evoked heat pain perception and heat pain-related evoked potentials without inducing warm perception threshold changes in SCI patients. This phenomenon should be taken into account in the clinical evaluation and management of pain in patients receiving baclofen. © 2012 European Federation of International Association for the Study of Pain Chapters.

Visual evoked potentials in patients after methanol poisoning.

PubMed

Urban, Pavel; Zakharov, Sergey; Diblík, Pavel; Pelclová, Daniela; Ridzoň, Petr

2016-01-01

We report the results of the visual evoked potentials (VEP) examination in patients after severe poisoning by methanol. The group of 47 patients (38 males and 9 females) was assembled out of persons who survived an outbreak of poisoning by the methanol adulterated alcohol beverages, which happened in the Czech Republic in 2012-2013. The visual evoked potentials examination was performed using monocular checkerboard pattern-reversal stimulation. Two criteria of abnormality were chosen: missing evoked response, and wave P1 latency > 117 ms. Non-parametric statistical methods (median, range, and the median test) were used to analyze factors influencing the VEP abnormality. The visual evoked potential was abnormal in 20 patients (43%), 5 of them had normal visual acuity on the Snellen chart. The VEP abnormality did not correlate significantly with initial serum concentrations of methanol, formic acid or lactate; however, it showed statistically significant inverse relation to the initial serum pH: the subgroup with the abnormal VEP had significantly lower median pH in comparison with the subgroup with the normal VEP (7.16 vs. 7.34, p = 0.04). The abnormality was not related to chronic alcohol abuse. The visual evoked potentials examination appeared sensitive enough to detected even subclinical impairment of the optic system. Metabolic acidosis is likely to be the key factor related to the development of visual damage induced by methanol. The examination performed with a delay of 1-9 months after the poisoning documented the situation relatively early after the event. It is considered as a baseline for the planned long-term follow-up of the patients, which will make it possible to assess the dynamics of the observed changes, their reversibility, and the occurrence of potential late sequelae. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

A simple model for the generation of the vestibular evoked myogenic potential (VEMP).

PubMed

Wit, Hero P; Kingma, Charlotte M

2006-06-01

To describe the mechanism by which the vestibular evoked myogenic potential is generated. Vestibular evoked myogenic potential generation is modeled by adding a large number of muscle motor unit action potentials. These action potentials occur randomly in time along a 100 ms long time axis. But because between approximately 15 and 20 ms after a loud short sound stimulus (almost) no action potentials are generated during VEMP measurements in human subjects, no action potentials are present in the model during this time. The evoked potential is the result of the lack of amplitude cancellation in the averaged surface electromyogram at the edges of this 5 ms long time interval. The relatively simple model describes generation and some properties of the vestibular evoked myogenic potential very well. It is shown that, in contrast with other evoked potentials (BAEPs, VERs), the vestibular evoked myogenic potential is the result of an interruption of activity and not that of summed synchronized neural action potentials.

Recording Visual Evoked Potentials and Auditory Evoked P300 at 9.4T Static Magnetic Field

PubMed Central

Hahn, David; Boers, Frank; Shah, N. Jon

2013-01-01

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4T were not different from those recorded at 0T. The amplitudes of ERPs were higher at 9.4T when compared to recordings at 0T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses. PMID:23650538

Recording visual evoked potentials and auditory evoked P300 at 9.4T static magnetic field.

PubMed

Arrubla, Jorge; Neuner, Irene; Hahn, David; Boers, Frank; Shah, N Jon

2013-01-01

Simultaneous recording of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has shown a number of advantages that make this multimodal technique superior to fMRI alone. The feasibility of recording EEG at ultra-high static magnetic field up to 9.4 T was recently demonstrated and promises to be implemented soon in fMRI studies at ultra high magnetic fields. Recording visual evoked potentials are expected to be amongst the most simple for simultaneous EEG/fMRI at ultra-high magnetic field due to the easy assessment of the visual cortex. Auditory evoked P300 measurements are of interest since it is believed that they represent the earliest stage of cognitive processing. In this study, we investigate the feasibility of recording visual evoked potentials and auditory evoked P300 in a 9.4 T static magnetic field. For this purpose, EEG data were recorded from 26 healthy volunteers inside a 9.4 T MR scanner using a 32-channel MR compatible EEG system. Visual stimulation and auditory oddball paradigm were presented in order to elicit evoked related potentials (ERP). Recordings made outside the scanner were performed using the same stimuli and EEG system for comparison purposes. We were able to retrieve visual P100 and auditory P300 evoked potentials at 9.4 T static magnetic field after correction of the ballistocardiogram artefact using independent component analysis. The latencies of the ERPs recorded at 9.4 T were not different from those recorded at 0 T. The amplitudes of ERPs were higher at 9.4 T when compared to recordings at 0 T. Nevertheless, it seems that the increased amplitudes of the ERPs are due to the effect of the ultra-high field on the EEG recording system rather than alteration in the intrinsic processes that generate the electrophysiological responses.

Median and ulnar muscle and sensory evoked potentials.

PubMed

Felsenthal, G

1978-08-01

The medical literature was reviewed to find suggested clinical applications of the study of the amplitude of evoked muscle action potentials (MAP) and sensory action potentials (SAP). In addition, the literature was reviewed to ascertain the normal amplitude and duration of the evoked MAP and SAP as well as the factors affecting the amplitude: age, sex, temperature, ischemia. The present study determined the normal amplitude and duration of the median and ulnar MAP and SAP in fifty normal subjects. The amplitude of evoked muscle or sensory action potentials depends on multiple factors. Increased skin resistance, capacitance, and impedance at the surface of the recording electrode diminishes the amplitude. Similarly, increased distance from the source of the action potential diminishes its amplitude. Increased interelectrode distance increases the amplitude of the bipolarly recorded sensory action potential until a certain interelectrode distance is exceeded and the diphasic response becomes tri- or tetraphasic. Artifact or poor technique may reduce the potential difference between the recording electrodes or obscure the late positive phase of the action potential and thus diminish the peak to peak amplitude measurement. Intraindividual comparison indicated a marked difference of amplitude in opposite hands. The range of the MAP of the abductor pollicis brevis in one hand was 40.0--100% of the response in the opposite hand. For the abductor digiti minimi, the MAP was 58.5--100% of the response of the opposite hand. The median and ulnar SAP was between 50--100% of the opposite SAP. Consequent to these findings the effect of hand dominance on the amplitude of median and ulnar evoked muscle and sensory action potentials was studied in 41 right handed volunteers. The amplitudes of the median muscle action potential (p less than 0.02) and the median and ulnar sensory action potentials (p less than 0.001) were significantly less in the dominant hand. There was no

[The influence of various acoustic stimuli upon the cumulative action potential (SAP) of the auditory nerves in guinea pigs (author's transl)].

PubMed

Hofmann, G; Kraak, W

1976-08-31

The impact of various acoustic stimuli upon the cumulative action potential of the auditory nerves in guinea pigs is investigated by means of the averaging method. It was found that the potential amplitude within the measuring range increases with the logarithm of the rising sonic pressure velocity. Unlike the evoked response audiometry (ERA), this potential seems unsuitable for furnishing information of the frequency-dependent threshold course.

Recording and assessment of evoked potentials with electrode arrays.

PubMed

Miljković, N; Malešević, N; Kojić, V; Bijelić, G; Keller, T; Popović, D B

2015-09-01

In order to optimize procedure for the assessment of evoked potentials and to provide visualization of the flow of action potentials along the motor systems, we introduced array electrodes for stimulation and recording and developed software for the analysis of the recordings. The system uses a stimulator connected to an electrode array for the generation of evoked potentials, an electrode array connected to the amplifier, A/D converter and computer for the recording of evoked potentials, and a dedicated software application. The method has been tested for the assessment of the H-reflex on the triceps surae muscle in six healthy humans. The electrode array with 16 pads was positioned over the posterior aspect of the thigh, while the recording electrode array with 16 pads was positioned over the triceps surae muscle. The stimulator activated all the pads of the stimulation electrode array asynchronously, while the signals were recorded continuously at all the recording sites. The results are topography maps (spatial distribution of evoked potentials) and matrices (spatial visualization of nerve excitability). The software allows the automatic selection of the lowest stimulation intensity to achieve maximal H-reflex amplitude and selection of the recording/stimulation pads according to predefined criteria. The analysis of results shows that the method provides rich information compared with the conventional recording of the H-reflex with regard the spatial distribution.

Combined evoked potentials in co-occuring attention deficit hyperactivity disorder and epilepsy.

PubMed

Major, Zoltán Zsigmond

2011-07-30

Evoked potentials, both stimulus related and event related, show disturbances in attention deficit-hyperactivity disorder and epilepsies, too. This study was designed to evaluate if these potentials are characteristically influenced by the presence of the two diseases, individually, and in the case of co-occurrence. Forty children were included, and four groups were formed, control group, ADHD group, epilepsy group and a group with the comorbidity of epilepsy and ADHD. Epilepsy patients were under proper antiepileptic treatment; ADHD patients were free of specific therapy. Brainstem auditory evoked potentials, visual evoked potentials and auditory P300 evaluation were performed. The latency of the P100 and N135 visual evoked potential components was significantly extended by the presence of epilepsy. If ADHD was concomitantly present, this effect was attenuated. Brainstem auditory evoked potential components were prolonged in the presence of the comorbidity, considering the waves elicited in the brainstem. P300 latencies were prolonged by the presence of co-occurring ADHD and epilepsy. Feedback parameters showed overall reduction of the tested cognitive performances in the ADHD group. Disturbances produced by the presence of ADHD-epilepsy comorbidity reveal hypothetically a linked physiopathological path for both diseases, and offers an approach with possible diagnostic importance, combined evoked potential recordings.

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

PubMed

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

2008-01-01

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

[Application of evoked potentials monitoring in total thoracoabdominal aorta aneurysm repair].

PubMed

Duan, Y Y; Zheng, J; Pan, X D; Zhu, J M; Liu, Y M; Ge, Y P; Cheng, L J; Sun, L Z

2016-04-05

To evaluate the application value of evoked potentials (EP) monitoring in patients undergoing aorta-iliac bypass for total thoracoabdominal aorta aneurysm repair (tTAAAR). A prospective study, with a total of 31 patients undergoing tTAAAR and intraoperative EP monitoring from June 2014 to April 2015 was carried out. The results of intraoperative evoked potentials, clinical outcomes and follow-up data of patients were collected for further evaluation. The EP wave disappeared [motor evoked potentials for (55.6±18.1) min, somatosensory evoked potentials for (50.3±18.7) min] after proximal descending aorta being clamped, and gradually recovered after the segment arteries of spine cord were reconstructed. The EP wave was restored to normal level at the end of operation in all the cases. The somatosensory evoked potentials remained unchanged in 2 cases (false negative). One case died after operation. No spinal cord injury occurred. The median follow-up after operation was 10 months (5-14 months). There was no delayed neurological deficit. EP provided an on-line monitoring of the condition of spinal cord function, which become an intraoperative protocol to avoid the irreversible injury of spinal cord.

[The algorithms and development for the extraction of evoked potentials].

PubMed

Niu, Jie; Qiu, Tianshuang

2004-06-01

The extraction of evoked potentials is a main subject in the area of brain signal processing. In recent years, the single-trial extraction of evoked potentials has been focused on by many studies. In this paper, the approaches based on the wavelet transform, the neural network, the high order acumulants and the independent component analysis are briefly reviewed.

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials

PubMed Central

Jones, Matthew D.; Taylor, Janet L.; Booth, John; Barry, Benjamin K.

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1–SEPs; Experiment 2–LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = −0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = −0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = −0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = −0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia. PMID:27965587

Exploring the Mechanisms of Exercise-Induced Hypoalgesia Using Somatosensory and Laser Evoked Potentials.

PubMed

Jones, Matthew D; Taylor, Janet L; Booth, John; Barry, Benjamin K

2016-01-01

Exercise-induced hypoalgesia is well described, but the underlying mechanisms are unclear. The aim of this study was to examine the effect of exercise on somatosensory evoked potentials, laser evoked potentials, pressure pain thresholds and heat pain thresholds. These were recorded before and after 3-min of isometric elbow flexion exercise at 40% of the participant's maximal voluntary force, or an equivalent period of rest. Exercise-induced hypoalgesia was confirmed in two experiments (Experiment 1-SEPs; Experiment 2-LEPs) by increased pressure pain thresholds at biceps brachii (24.3 and 20.6% increase in Experiment 1 and 2, respectively; both d > 0.84 and p < 0.001) and first dorsal interosseous (18.8 and 21.5% increase in Experiment 1 and 2, respectively; both d > 0.57 and p < 0.001). In contrast, heat pain thresholds were not significantly different after exercise (forearm: 10.8% increase, d = 0.35, p = 0.10; hand: 3.6% increase, d = 0.06, p = 0.74). Contrasting effects of exercise on the amplitude of laser evoked potentials (14.6% decrease, d = -0.42, p = 0.004) and somatosensory evoked potentials (10.9% increase, d = -0.02, p = 1) were also observed, while an equivalent period of rest showed similar habituation (laser evoked potential: 7.3% decrease, d = -0.25, p = 0.14; somatosensory evoked potential: 20.7% decrease, d = -0.32, p = 0.006). The differential response of pressure pain thresholds and heat pain thresholds to exercise is consistent with relative insensitivity of thermal nociception to the acute hypoalgesic effects of exercise. Conflicting effects of exercise on somatosensory evoked potentials and laser evoked potentials were observed. This may reflect non-nociceptive contributions to the somatosensory evoked potential, but could also indicate that peripheral nociceptors contribute to exercise-induced hypoalgesia.

Auditory evoked potentials in two short-finned pilot whales (Globicephala macrorhynchus).

PubMed

Schlundt, Carolyn E; Dear, Randall L; Houser, Dorian S; Bowles, Ann E; Reidarson, Tom; Finneran, James J

2011-02-01

The hearing sensitivities of two short-finned pilot whales (Globicephala macrorhynchus) were investigated by measuring auditory evoked potentials generated in response to clicks and sinusoidal amplitude modulated (SAM) tones. The first whale tested, an adult female, was a long-time resident at SeaWorld San Diego with a known health history. Click-evoked responses in this animal were similar to those measured in other echolocating odontocetes. Auditory thresholds were comparable to dolphins of similar age determined with similar evoked potential methods. The region of best sensitivity was near 40 kHz and the upper limit of functional hearing was between 80 and 100 kHz. The second whale tested, a juvenile male, was recently stranded and deemed non-releasable. Click-evoked potentials were not detected in this animal and testing with SAM tones suggested severe hearing loss above 10 kHz.

Time Perception and Evoked Potentials

DTIC Science & Technology

1988-07-01

ARI Research Note 88-69 0 MitnS.Ktohe U.0 ... Ann-r (. Time Perception and Evoked Potentials Paul FraisseDT ( Lfniversit6 Rene Descartes E LECTE...JOHNSON 00L, [N Technical Dicctojr Cmad Research accomplished under contract for the Department of the Army C. Universite Rene Descartes , Paris )r...ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK Labrato-ire de Psychologie Experimental AREA• WORK UNIT NUMBERS Universite Rene Descartes

Postoperative neurological deficits may occur despite unchanged intraoperative somatosensory evoked potentials.

PubMed

Lesser, R P; Raudzens, P; Lüders, H; Nuwer, M R; Goldie, W D; Morris, H H; Dinner, D S; Klem, G; Hahn, J F; Shetter, A G

1986-01-01

We describe 6 patients who demonstrated postoperative neurological deficits despite unchanged somatosensory evoked potentials during intraoperative monitoring. Although there is both experimental and clinical evidence that somatosensory evoked potentials are sensitive to some types of intraoperative mishap, the technique should be employed with an awareness of its possible limitations.

Local classifiers for evoked potentials recorded from behaving rats.

PubMed

Jakuczun, Wit; Kublik, Ewa; Wójcik, Daniel K; Wróbel, Andrzej

2005-01-01

Dynamic states of the brain determine the way information is processed in local neural networks. We have applied classical conditioning paradigm in order to study whether habituated and aroused states can be differentiated in single barrel column of rat's somatosensory cortex by means of analysis of field potentials evoked by stimulation of a single vibrissa. A new method using local classifiers is presented which allows for reliable and meaningful classification of single evoked potentials which might be consequently attributed to different functional states of the cortical column.

Properties of visual evoked potentials to onset of movement on a television screen.

PubMed

Kubová, Z; Kuba, M; Hubacek, J; Vít, F

1990-08-01

In 80 subjects the dependence of movement-onset visual evoked potentials on some measures of stimulation was examined, and these responses were compared with pattern-reversal visual evoked potentials to verify the effectiveness of pattern movement application for visual evoked potential acquisition. Horizontally moving vertical gratings were generated on a television screen. The typical movement-onset reactions were characterized by one marked negative peak only, with a peak time between 140 and 200 ms. In all subjects the sufficient stimulus duration for acquisition of movement-onset-related visual evoked potentials was 100 ms; in some cases it was only 20 ms. Higher velocity (5.6 degree/s) produced higher amplitudes of movement-onset visual evoked potentials than did the lower velocity (2.8 degrees/s). In 80% of subjects, the more distinct reactions were found in the leads from lateral occipital areas (in 60% from the right hemisphere), with no correlation to handedness of subjects. Unlike pattern-reversal visual evoked potentials, the movement-onset responses tended to be larger to extramacular stimulation (annular target of 5 degrees-9 degrees) than to macular stimulation (circular target of 5 degrees diameter).

Automated cortical auditory evoked potentials threshold estimation in neonates.

PubMed

Oliveira, Lilian Sanches; Didoné, Dayane Domeneghini; Durante, Alessandra Spada

2018-02-02

The evaluation of Cortical Auditory Evoked Potential has been the focus of scientific studies in infants. Some authors have reported that automated response detection is effective in exploring these potentials in infants, but few have reported their efficacy in the search for thresholds. To analyze the latency, amplitude and thresholds of Cortical Auditory Evoked Potential using an automatic response detection device in a neonatal population. This is a cross-sectional, observational study. Cortical Auditory Evoked Potentials were recorded in response to pure-tone stimuli of the frequencies 500, 1000, 2000 and 4000Hz presented in an intensity range between 0 and 80dB HL using a single channel recording. P1 was performed in an exclusively automated fashion, using Hotelling's T 2 statistical test. The latency and amplitude were obtained manually by three examiners. The study comprised 39 neonates up to 28 days old of both sexes with presence of otoacoustic emissions and no risk factors for hearing loss. With the protocol used, Cortical Auditory Evoked Potential responses were detected in all subjects at high intensity and thresholds. The mean thresholds were 24.8±10.4dB NA, 25±9.0dB NA, 28±7.8dB NA and 29.4±6.6dB HL for 500, 1000, 2000 and 4000Hz, respectively. Reliable responses were obtained in the assessment of cortical auditory potentials in the neonates assessed with a device for automatic response detection. Copyright © 2018 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Effects of single cycle binaural beat duration on auditory evoked potentials.

PubMed

Mihajloski, Todor; Bohorquez, Jorge; Özdamar, Özcan

2014-01-01

Binaural beat (BB) illusions are experienced as continuous central pulsations when two sounds with slightly different frequencies are delivered to each ear. It has been shown that steady-state auditory evoked potentials (AEPs) to BBs can be captured and investigated. The authors recently developed a new method of evoking transient AEPs to binaural beats using frequency modulated stimuli. This methodology was able to create single BBs in predetermined intervals with varying carrier frequencies. This study examines the effects of the BB duration and the frequency modulating component of the stimulus on the binaural beats and their evoked potentials. Normal hearing subjects were tested with a set of four durations (25, 50, 100, and 200 ms) with two stimulation configurations, binaural dichotic (binaural beats) and diotic (frequency modulation). The results obtained from the study showed that out of the given durations, the 100 ms beat, was capable of evoking the largest amplitude responses. The frequency modulation effect showed a decrease in peak amplitudes with increasing beat duration until their complete disappearance at 200 ms. Even though, at 200 ms, the frequency modulation effects were not present, the binaural beats were still perceived and captured as evoked potentials.

Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips.

PubMed

Todd, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

2014-06-01

Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Refractory episodic vertigo: role of intratympanic gentamicin and vestibular evoked myogenic potentials.

PubMed

Celis-Aguilar, Erika; Hinojosa-González, Ramon; Vales-Hidalgo, Olivia; Coutinho-Toledo, Heloisa

Even today, the treatment of intractable vertigo remains a challenge. Vestibular ablation with intratympanic gentamicin stands as a good alternative in the management of refractory vertigo patients. To control intractable vertigo through complete saccular and horizontal canal vestibular ablation with intratympanic gentamicin treatment. Patients with refractory episodic vertigo were included. The inclusion criteria were: unilateral ear disease, moderate to profound sensorineural hearing loss, and failure to other treatments. Included patients underwent 0.5-0.8mL of gentamicin intratympanic application at a 30mg/mL concentration. Vestibular ablation was confirmed by the absence of response on cervical vestibular evoked myogenic potentials and no response on caloric tests. Audiometry, electronystagmography with iced water, and vestibular evoked myogenic potentials were performed in all patients. Ten patients were included; nine patients with Meniere's disease and one patient with (late onset) delayed hydrops. Nine patients showed an absent response on vestibular evoked myogenic potentials and no response on caloric tests. The only patient with low amplitude on cervical vestibular evoked myogenic potentials had vertigo recurrence. Vertigo control was achieved in 90% of the patients. One patient developed hearing loss >30dB. Cervical vestibular evoked myogenic potentials confirmed vestibular ablation in patients treated with intratympanic gentamicin. High-grade vertigo control was due to complete saccular and horizontal canal ablation (no response to iced water in electronystagmography and no response on cervical vestibular evoked myogenic potentials). Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Cortical evoked potentials to an auditory illusion: binaural beats.

PubMed

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2009-08-01

To define brain activity corresponding to an auditory illusion of 3 and 6Hz binaural beats in 250Hz or 1000Hz base frequencies, and compare it to the sound onset response. Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000Hz to one ear and 3 or 6Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3Hz and 6Hz, in base frequencies of 250Hz and 1000Hz. Tones were 2000ms in duration and presented with approximately 1s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. All stimuli evoked tone-onset P(50), N(100) and P(200) components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P(50) had significantly different sources than the beats-evoked oscillations; and N(100) and P(200) sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the scalp.

Cortical Evoked Potentials to an Auditory Illusion: Binaural Beats

PubMed Central

Pratt, Hillel; Starr, Arnold; Michalewski, Henry J.; Dimitrijevic, Andrew; Bleich, Naomi; Mittelman, Nomi

2009-01-01

Objective: To define brain activity corresponding to an auditory illusion of 3 and 6 Hz binaural beats in 250 Hz or 1,000 Hz base frequencies, and compare it to the sound onset response. Methods: Event-Related Potentials (ERPs) were recorded in response to unmodulated tones of 250 or 1000 Hz to one ear and 3 or 6 Hz higher to the other, creating an illusion of amplitude modulations (beats) of 3 Hz and 6 Hz, in base frequencies of 250 Hz and 1000 Hz. Tones were 2,000 ms in duration and presented with approximately 1 s intervals. Latency, amplitude and source current density estimates of ERP components to tone onset and subsequent beats-evoked oscillations were determined and compared across beat frequencies with both base frequencies. Results: All stimuli evoked tone-onset P50, N100 and P200 components followed by oscillations corresponding to the beat frequency, and a subsequent tone-offset complex. Beats-evoked oscillations were higher in amplitude with the low base frequency and to the low beat frequency. Sources of the beats-evoked oscillations across all stimulus conditions located mostly to left lateral and inferior temporal lobe areas in all stimulus conditions. Onset-evoked components were not different across stimulus conditions; P50 had significantly different sources than the beats-evoked oscillations; and N100 and P200 sources located to the same temporal lobe regions as beats-evoked oscillations, but were bilateral and also included frontal and parietal contributions. Conclusions: Neural activity with slightly different volley frequencies from left and right ear converges and interacts in the central auditory brainstem pathways to generate beats of neural activity to modulate activities in the left temporal lobe, giving rise to the illusion of binaural beats. Cortical potentials recorded to binaural beats are distinct from onset responses. Significance: Brain activity corresponding to an auditory illusion of low frequency beats can be recorded from the

Laser and somatosensory evoked potentials in amyotrophic lateral sclerosis.

PubMed

Isak, Baris; Tankisi, Hatice; Johnsen, Birger; Pugdahl, Kirsten; Finnerup, Nanna Brix; Fuglsang-Frederiksen, Anders

2016-10-01

Mild involvement of sensory nerves has been reported in previous studies in ALS patients. In this study, we assessed sensory pathways in ALS patients using laser evoked potentials (LEPs) and somatosensory evoked potentials (SSEPs). We recruited 18 ALS patients and 31 healthy subjects. Neodymium-doped yttrium aluminium perovskite (Nd:YAP)-laser was used to evoke LEPs in upper (UE) and lower (LE) extremities. N1 and N2P2 potentials were obtained from contralateral insular cortex (T3 or T4) and vertex (Cz), respectively. Median SSEPs were recorded from C3' or C4' and tibial SSEPs from Cz'. Compared to controls, ALS patients had longer N2 and P2 latencies, and smaller N2P2 amplitudes in both UE- and LE-LEPs (p<0.05), and longer latencies for median and tibial SSEPs (p<0.05). LEPs and SSEPs were abnormal in 72.2% and 56.6% patients, respectively. Cortical potentials showed that A-beta or A-delta sensory fibres, or both, were impaired in more than half of the ALS patients. The findings support that ALS is a multi-systemic disorder involving, although to a lesser degree, other systems than the motor. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Index finger somatosensory evoked potentials in blind Braille readers.

PubMed

Giriyappa, Dayananda; Subrahmanyam, Roopakala Mysore; Rangashetty, Srinivasa; Sharma, Rajeev

2009-01-01

Traditionally, vision has been considered the dominant modality in our multi-sensory perception of the surrounding world. Sensory input via non-visual tracts becomes of greater behavioural relevance in totally blind individuals to enable effective interaction with the world around them. These include audition and tactile perceptions, leading to an augmentation in these perceptions when compared with normal sighted individuals. The objective of the present work was to study the index finger somatosensory evoked potentials (SEPs) in totally blind and normal sighted individuals. SEPs were recorded in 15 Braille reading totally blind females and compared with 15 age-matched normal sighted females. Latency and amplitudes of somatosensory evoked potential waveforms (N9, N13, and N20) were measured. Amplitude of N20 SEP (a cortical somatosensory evoked potential) was significantly larger in the totally blind than in normal sighted individuals (p < 0.05). The amplitudes of N9 and N13 SEP and the latencies of all recorded SEPs showed no significant differences. Blindness has a profound effect on the Braille reading right index finger. Totally blind Braille readers have larger N20 amplitude, suggestive of greater somatosensory cortical representation of the Braille reading index finger.

Mapping the vestibular evoked myogenic potential (VEMP).

PubMed

Colebatch, James G

2012-01-01

Effects of different electrode placements and indifferent electrodes were investigated for the vestibular evoked myogenic potential (VEMP) recorded from the sternocleidomastoid muscle (SCM). In 5 normal volunteers, the motor point of the left SCM was identified and an electrode placed there. A grid of 7 additional electrodes was laid out, along and across the SCM, based upon the location of the motor point. One reference electrode was placed over the sternoclavicular joint and another over C7. There were clear morphological changes with differing recording sites and for the two reference electrodes, but the earliest and largest responses were recorded from the motor point. The C7 reference affected the level of rectified EMG and was associated with an initial negativity in some electrodes. The latencies of the p13 potentials increased with distance from the motor point but the n23 latencies did not. Thus the p13 potential behaved as a travelling wave whereas the n23 behaved as a standing wave. The C7 reference may be contaminated by other evoked myogenic activity. Ideally recordings should be made with an active electrode over the motor point.

Safe Use of Acoustic Vestibular-Evoked Myogenic Potential Stimuli: Protocol and Patient-Specific Considerations.

PubMed

Portnuff, Cory D F; Kleindienst, Samantha; Bogle, Jamie M

2017-09-01

Vestibular-evoked myogenic potentials (VEMPs) are commonly used clinical assessments for patients with complaints of dizziness. However, relatively high air-conducted stimuli are required to elicit the VEMP, and ultimately may compromise safe noise exposure limits. Recently, research has reported the potential for noise-induced hearing loss (NIHL) from VEMP stimulus exposure through studies of reduced otoacoustic emission levels after VEMP testing, as well as a recent case study showing permanent sensorineural hearing loss associated with VEMP exposure. The purpose of this report is to review the potential for hazardous noise exposure from VEMP stimuli and to suggest clinical parameters for safe VEMP testing. Literature review with presentation of clinical guidelines and a clinical tool for estimating noise exposure. The literature surrounding VEMP stimulus-induced hearing loss is reviewed, including several cases of overexposure. The article then presents a clinical calculation tool for the estimation of a patient's safe noise exposure from VEMP stimuli, considering stimulus parameters, and includes a discussion of how varying stimulus parameters affect a patient's noise exposure. Finally, recommendations are provided for recognizing and managing specific patient populations who may be at higher risk for NIHL from VEMP stimulus exposure. A sample protocol is provided that allows for safe noise exposure. VEMP stimuli have the potential to cause NIHL due to high sound exposure levels. However, with proper safety protocols in place, clinicians may reduce or eliminate this risk to their patients. Use of the tools provided, including the noise exposure calculation tool and sample protocols, may help clinicians to understand and ensure safe use of VEMP stimuli. American Academy of Audiology

Phantom somatosensory evoked potentials following selective intraneural electrical stimulation in two amputees.

PubMed

Granata, Giuseppe; Di Iorio, Riccardo; Romanello, Roberto; Iodice, Francesco; Raspopovic, Stanisa; Petrini, Francesco; Strauss, Ivo; Valle, Giacomo; Stieglitz, Thomas; Čvančara, Paul; Andreu, David; Divoux, Jean-Louis; Guiraud, David; Wauters, Loic; Hiairrassary, Arthur; Jensen, Winnie; Micera, Silvestro; Rossini, Paolo Maria

2018-06-01

The aim of the paper is to objectively demonstrate that amputees implanted with intraneural interfaces are truly able to feel a sensation in the phantom hand by recording "phantom" somatosensory evoked potentials from the corresponding brain areas. We implanted four transverse intrafascicular multichannel electrodes, available with percutaneous connections to a multichannel electrical stimulator, in the median and ulnar nerves of two left trans-radial amputees. Two channels of the implants that were able to elicit sensations during intraneural nerve stimulation were chosen, in both patients, for recording somatosensory evoked potentials. We recorded reproducible evoked responses by stimulating the median and the ulnar nerves in both cases. Latencies were in accordance with the arrival of somatosensory information to the primary somatosensory cortex. Our results provide evidence that sensations generated by intraneural stimulation are truly perceived by amputees and located in the phantom hand. Moreover, our results strongly suggest that sensations perceived in different parts of the phantom hand result in different evoked responses. Somatosensory evoked potentials obtained by selective intraneural electrical stimulation in amputee patients are a useful tool to provide an objective demonstration of somatosensory feedback in new generation bidirectional prostheses. Copyright © 2018. Published by Elsevier B.V.

Cortico-centric effects of general anesthetics on cerebrocortical evoked potentials.

PubMed

Voss, Logan J; Sleigh, James W

2015-12-01

Despite their ubiquitous use for rendering patients unconscious for surgery, our understanding of how general anesthetics cause hypnosis remains rudimentary at best. Recent years have seen increased interest in "top-down" cortico-centric theories of anesthetic action. The aim of this study was to explore this by investigating direct cortical effects of anesthetics on cerebrocortical evoked potentials in isolated mouse brain slices. Evoked potentials were elicited in cortical layer IV by electrical stimulation of the underlying white matter. The effects of three anesthetics (ketamine, etomidate, and isoflurane) on the amplitude, latency, and slope of short-latency evoked potentials were quantified. The N2/P3/N4 potentials–which represent the early cortical response–were enhanced by etomidate (increased P3-N4 slope, P <0.01), maintained by ketamine, and reduced by isoflurane (lower N2/P3 amplitude, P <0.01). These effects closely resemble those seen in vivo for the same drugs and point to a cortical mechanism independent of effects on subcortical structures such as the thalamus.

Temporal processing and long-latency auditory evoked potential in stutterers.

PubMed

Prestes, Raquel; de Andrade, Adriana Neves; Santos, Renata Beatriz Fernandes; Marangoni, Andrea Tortosa; Schiefer, Ana Maria; Gil, Daniela

Stuttering is a speech fluency disorder, and may be associated with neuroaudiological factors linked to central auditory processing, including changes in auditory processing skills and temporal resolution. To characterize the temporal processing and long-latency auditory evoked potential in stutterers and to compare them with non-stutterers. The study included 41 right-handed subjects, aged 18-46 years, divided into two groups: stutterers (n=20) and non-stutters (n=21), compared according to age, education, and sex. All subjects were submitted to the duration pattern tests, random gap detection test, and long-latency auditory evoked potential. Individuals who stutter showed poorer performance on Duration Pattern and Random Gap Detection tests when compared with fluent individuals. In the long-latency auditory evoked potential, there was a difference in the latency of N2 and P3 components; stutterers had higher latency values. Stutterers have poor performance in temporal processing and higher latency values for N2 and P3 components. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

A Perturbation Based Decomposition of Compound-Evoked Potentials for Characterization of Nerve Fiber Size Distributions.

PubMed

Szlavik, Robert B

2016-02-01

The characterization of peripheral nerve fiber distributions, in terms of diameter or velocity, is of clinical significance because information associated with these distributions can be utilized in the differential diagnosis of peripheral neuropathies. Electro-diagnostic techniques can be applied to the investigation of peripheral neuropathies and can yield valuable diagnostic information while being minimally invasive. Nerve conduction velocity studies are single parameter tests that yield no detailed information regarding the characteristics of the population of nerve fibers that contribute to the compound-evoked potential. Decomposition of the compound-evoked potential, such that the velocity or diameter distribution of the contributing nerve fibers may be determined, is necessary if information regarding the population of contributing nerve fibers is to be ascertained from the electro-diagnostic study. In this work, a perturbation-based decomposition of compound-evoked potentials is proposed that facilitates determination of the fiber diameter distribution associated with the compound-evoked potential. The decomposition is based on representing the single fiber-evoked potential, associated with each diameter class, as being perturbed by contributions, of varying degree, from all the other diameter class single fiber-evoked potentials. The resultant estimator of the contributing nerve fiber diameter distribution is valid for relatively large separations in diameter classes. It is also useful in situations where the separation between diameter classes is small and the concomitant single fiber-evoked potentials are not orthogonal.

Intraoperative Subcortical Fiber Mapping with Subcortico-Cortical Evoked Potentials.

PubMed

Enatsu, Rei; Kanno, Aya; Ohtaki, Shunya; Akiyama, Yukinori; Ochi, Satoko; Mikuni, Nobuhiro

2016-02-01

During brain surgery, there are difficulties associated with identifying subcortical fibers with no clear landmarks. We evaluated the usefulness of cortical evoked potentials with subcortical stimuli (subcortico-cortical evoked potential [SCEP]) in identifying subcortical fibers intraoperatively. We used SCEP to identify the pyramidal tract in 4 patients, arcuate fasciculus in 1 patient, and both in 2 patients during surgical procedures. After resection, a 1 × 4-electrode plate was placed on the floor of the removal cavity and 1-Hz alternating electrical stimuli were delivered to this electrode. A 4 × 5 recording electrode plate was placed on the central cortical areas to map the pyramidal tract and temporoparietal cortical areas for the arcuate fasciculus. SCEPs were obtained by averaging electrocorticograms time locked to the stimulus onset. The subcortical stimulation within 15 mm of the target fiber induced cortical evoked potentials in the corresponding areas, whereas the stimulation apart from 20 mm did not. Five patients showed transient worsening of neurologic symptoms after surgery. However, all patients recovered. SCEP was useful for identifying subcortical fibers and confirmed the preservation of these fibers. This technique is expected to contribute to the effectiveness and safety of resective surgery in patients with lesions close to eloquent areas. Copyright © 2016 Elsevier Inc. All rights reserved.

Vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration applied at the nasion.

PubMed

Todd, Neil P M; McLean, Aisha; Paillard, Aurore; Kluk, Karolina; Colebatch, James G

2014-12-01

We report the results of a study to record vestibular evoked potentials (VsEPs) of cortical origin produced by impulsive acceleration (IA). In a sample of 12 healthy participants, evoked potentials recorded by 70 channel electroencephalography were obtained by IA stimulation at the nasion and compared with evoked potentials from the same stimulus applied to the forefingers. The nasion stimulation gave rise to a series of positive and negative deflections in the latency range of 26-72 ms, which were dependent on the polarity of the applied IA. In contrast, evoked potentials from the fingers were characterised by a single N50/P50 deflection at about 50 ms and were polarity invariant. Source analysis confirmed that the finger evoked potentials were somatosensory in origin, i.e. were somatosensory evoked potentials, and suggested that the nasion evoked potentials plausibly included vestibular midline and frontal sources, as well as contributions from the eyes, and thus were likely VsEPs. These results show considerable promise as a new method for assessment of the central vestibular system by means of VsEPs produced by IA applied to the head.

Cortico-cortical evoked potentials for sites of early versus late seizure spread in stereoelectroencephalography.

PubMed

Lega, Bradley; Dionisio, Sasha; Flanigan, Patrick; Bingaman, William; Najm, Imad; Nair, Dileep; Gonzalez-Martinez, Jorge

2015-09-01

Cortico-cortical evoked potentials offer the possibility of understanding connectivity within seizure networks to improve diagnosis and more accurately identify candidates for seizure surgery. We sought to determine if cortico-cortical evoked potentials and post-stimulation oscillatory changes differ for sites of EARLY versus LATE ictal spread. 37 patients undergoing stereoelectroencephalography were tested using a cortico-cortical evoked potential paradigm. All electrodes were classified according to the speed of ictal spread. EARLY spread sites were matched to a LATE spread site equidistant from the onset zone. Root-mean-square was used to quantify evoked responses and post-stimulation gamma band power and coherence were extracted and compared. Sites of EARLY spread exhibited significantly greater evoked responses after stimulation across all patients (t(36)=2.973, p=0.004). Stimulation elicited enhanced gamma band activity at EARLY spread sites (t(36)=2.61, p=0.03, FDR corrected); this gamma band oscillation was highly coherent with the onset zone. Cortico-cortical evoked potentials and post-stimulation changes in gamma band activity differ between sites of EARLY versus LATE ictal spread. The oscillatory changes can help visualize connectivity within the seizure network. Copyright © 2015 Elsevier B.V. All rights reserved.

Multifocal visual evoked potentials for early glaucoma detection.

PubMed

Weizer, Jennifer S; Musch, David C; Niziol, Leslie M; Khan, Naheed W

2012-07-01

To compare multifocal visual evoked potentials (mfVEP) with other detection methods in early open-angle glaucoma. Ten patients with suspected glaucoma and 5 with early open-angle glaucoma underwent mfVEP, standard automated perimetry (SAP), short-wave automated perimetry, frequency-doubling technology perimetry, and nerve fiber layer optical coherence tomography. Nineteen healthy control subjects underwent mfVEP and SAP for comparison. Comparisons between groups involving continuous variables were made using independent t tests; for categorical variables, Fisher's exact test was used. Monocular mfVEP cluster defects were associated with an increased SAP pattern standard deviation (P = .0195). Visual fields that showed interocular mfVEP cluster defects were more likely to also show superior quadrant nerve fiber layer thinning by OCT (P = .0152). Multifocal visual evoked potential cluster defects are associated with a functional and an anatomic measure that both relate to glaucomatous optic neuropathy. Copyright 2012, SLACK Incorporated.

Narrow-band evoked oto-acoustic emission from ears with normal and pathologic conditions.

PubMed

Takeda, Taizo; Kakigi, Akinobu; Takebayashi, Shinji; Ohono, Satoshi; Nishioka, Rie; Nakatani, Hiroaki

2010-01-01

Evoked oto-acoustic emission (EOAE), in particular the slow component, is fragile with the inner ear lesions and is apt to disappear in impaired ears. This presence is thought to mean that inner ear is not badly damaged, and that the presence of EOAEs in early stage sudden deafness carries a good prognosis. Narrow-band EOAE analysis would open a potentially promising way to manage sensorineural deafness. The aim of present study was to evaluate the characteristics of EOAEs from pathologic ears by a narrow-band EOAE analysis, which allowed us to investigate amplitude, frequency content and latency of EOAEs simultaneously and also to easily detect weak echoes in cases with inner ear lesions. EOAEs were analyzed by investigating narrow-band frequency contents of EOAEs, filtered by a 100-Hz step of pass bandwidth in frequency regions from 1.0 to 2.0 kHz, and by 500 Hz of pass bandwidth in the frequency ranges of 0.5-1.0 and 2.0-5.0 kHz. EOAE testing was performed in 40 normal ears and 111 ears with pathologic disorders, including sudden deafness, Ménière's disease and surgically proven acoustic neurinomas. Spontaneous oto-acoustic emission was investigated in some cases. In acoustic neurinoma, especially computed tomography scan and magnetic resonance imaging tests were performed to assess the tumor size. (1) Narrow-band EOAE analysis revealed that EOAEs from normal ears were composed of two main echo trains and several sub-echoes. The main echo trains were divided into a fast component with a short latency of <10 ms and a slow component with a long latency of >10 ms. (2) EOAEs could often be detected from ears with moderate to severe hearing loss >45 dB HL in early stage sudden deafness. The prognosis of sudden deafness was good in cases where both a fast component and slow component were detected in the acute stage within 2 weeks after the deafness onset, and was pessimistic, when either or both of them failed to recover. (3) In Ménière's disease, EOAE was found

Long-latency auditory evoked potentials with verbal and nonverbal stimuli.

PubMed

Oppitz, Sheila Jacques; Didoné, Dayane Domeneghini; Silva, Débora Durigon da; Gois, Marjana; Folgearini, Jordana; Ferreira, Geise Corrêa; Garcia, Michele Vargas

2015-01-01

Long-latency auditory evoked potentials represent the cortical activity related to attention, memory, and auditory discrimination skills. Acoustic signal processing occurs differently between verbal and nonverbal stimuli, influencing the latency and amplitude patterns. To describe the latencies of the cortical potentials P1, N1, P2, N2, and P3, as well as P3 amplitude, with different speech stimuli and tone bursts, and to classify them in the presence and absence of these data. A total of 30 subjects with normal hearing were assessed, aged 18-32 years old, matched by gender. Nonverbal stimuli were used (tone burst; 1000Hz - frequent and 4000Hz - rare); and verbal (/ba/ - frequent; /ga/, /da/, and /di/ - rare). Considering the component N2 for tone burst, the lowest latency found was 217.45ms for the BA/DI stimulus; the highest latency found was 256.5ms. For the P3 component, the shortest latency with tone burst stimuli was 298.7 with BA/GA stimuli, the highest, was 340ms. For the P3 amplitude, there was no statistically significant difference among the different stimuli. For latencies of components P1, N1, P2, N2, P3, there were no statistical differences among them, regardless of the stimuli used. There was a difference in the latency of potentials N2 and P3 among the stimuli employed but no difference was observed for the P3 amplitude. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Stimulus novelty, task relevance and the visual evoked potential in man

NASA Technical Reports Server (NTRS)

Courchesne, E.; Hillyard, S. A.; Galambos, R.

1975-01-01

The effect of task relevance on P3 (waveform of human evoked potential) waves and the methodologies used to deal with them are outlined. Visual evoked potentials (VEPs) were recorded from normal adult subjects performing in a visual discrimination task. Subjects counted the number of presentations of the numeral 4 which was interposed rarely and randomly within a sequence of tachistoscopically flashed background stimuli. Intrusive, task-irrelevant (not counted) stimuli were also interspersed rarely and randomly in the sequence of 2s; these stimuli were of two types: simples, which were easily recognizable, and novels, which were completely unrecognizable. It was found that the simples and the counted 4s evoked posteriorly distributed P3 waves while the irrelevant novels evoked large, frontally distributed P3 waves. These large, frontal P3 waves to novels were also found to be preceded by large N2 waves. These findings indicate that the P3 wave is not a unitary phenomenon but should be considered in terms of a family of waves, differing in their brain generators and in their psychological correlates.

Evoked potentials are useful for diagnosis of neuromyelitis optica spectrum disorder.

PubMed

Ohnari, Keiko; Okada, Kazumasa; Takahashi, Toshiyuki; Mafune, Kosuke; Adachi, Hiroaki

2016-05-15

Neuromyelitis optica spectrum disorder (NMOSD) has been differentiated from relapsing-remitting multiple sclerosis (RRMS) by clinical, laboratory, and pathological findings, including the presence of the anti-aquaporin 4 antibody. Measurement of evoked potentials (EPs) is often used for the diagnosis of RRMS, although the possibility of applying EPs to the diagnosis of NMOSD has not been investigated in detail. Eighteen patients with NMOSD and 28 patients with RRMS were included in this study. The patients' neurological symptoms and signs were examined and their EPs were recorded. Characteristic findings were absence of visual evoked potentials and absence of motor evoked potentials in the lower extremities in patients with NMOSD, and a delay in these potentials in patients with RRMS. Most patients with NMOSD did not present abnormal subclinical EPs, whereas many patients with RRMS did. None of the patients with NMOSD showed abnormalities in auditory brainstem responses. NMOSD can be differentiated from RRMS by EP data obtained in the early stages of these diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

Marine bioacoustics and technology: The new world of marine acoustic ecology

NASA Astrophysics Data System (ADS)

Hastings, Mardi C.; Au, Whitlow W. L.

2012-11-01

Marine animals use sound for communication, navigation, predator avoidance, and prey detection. Thus the rise in acoustic energy associated with increasing human activity in the ocean has potential to impact the lives of marine animals. Thirty years ago marine bioacoustics primarily focused on evaluating effects of human-generated sound on hearing and behavior by testing captive animals and visually observing wild animals. Since that time rapidly changing electronic and computing technologies have yielded three tools that revolutionized how bioacousticians study marine animals. These tools are (1) portable systems for measuring electrophysiological auditory evoked potentials, (2) miniaturized tags equipped with positioning sensors and acoustic recording devices for continuous short-term acoustical observation rather than intermittent visual observation, and (3) passive acoustic monitoring (PAM) systems for remote long-term acoustic observations at specific locations. The beauty of these breakthroughs is their direct applicability to wild animals in natural habitats rather than only to animals held in captivity. Hearing capabilities of many wild species including polar bears, beaked whales, and reef fishes have now been assessed by measuring their auditory evoked potentials. Miniaturized acoustic tags temporarily attached to an animal to record its movements and acoustic environment have revealed the acoustic foraging behavior of sperm and beaked whales. Now tags are being adapted to fishes in effort to understand their behavior in the presence of noise. Moving and static PAM systems automatically detect and characterize biological and physical features of an ocean area without adding any acoustic energy to the environment. PAM is becoming a powerful technique for understanding and managing marine habitats. This paper will review the influence of these transformative tools on the knowledge base of marine bioacoustics and elucidation of relationships between marine

Steady-state evoked potentials possibilities for mental-state estimation

NASA Technical Reports Server (NTRS)

Junker, Andrew M.; Schnurer, John H.; Ingle, David F.; Downey, Craig W.

1988-01-01

The use of the human steady-state evoked potential (SSEP) as a possible measure of mental-state estimation is explored. A method for evoking a visual response to a sum-of-ten sine waves is presented. This approach provides simultaneous multiple frequency measurements of the human EEG to the evoking stimulus in terms of describing functions (gain and phase) and remnant spectra. Ways in which these quantities vary with the addition of performance tasks (manual tracking, grammatical reasoning, and decision making) are presented. Models of the describing function measures can be formulated using systems engineering technology. Relationships between model parameters and performance scores during manual tracking are discussed. Problems of unresponsiveness and lack of repeatability of subject responses are addressed in terms of a need for loop closure of the SSEP. A technique to achieve loop closure using a lock-in amplifier approach is presented. Results of a study designed to test the effectiveness of using feedback to consciously connect humans to their evoked response are presented. Findings indicate that conscious control of EEG is possible. Implications of these results in terms of secondary tasks for mental-state estimation and brain actuated control are addressed.

Are evoked potentials in patients with adult-onset pompe disease indicative of clinically relevant central nervous system involvement?

PubMed

Wirsching, Andreas; Müller-Felber, Wolfgang; Schoser, Benedikt

2014-08-01

Pompe disease is a multisystem autosomal recessive glycogen storage disease. Autoptic findings in patients with classic infantile and late-onset Pompe disease have proven that accumulation of glycogen can also be found in the peripheral and central nervous system. To assess the functional role of these pathologic findings, multimodal sensory evoked potentials were analyzed. Serial recordings for brainstem auditory, visual, and somatosensory evoked potentials of 11 late-onset Pompe patients were reviewed. Data at the onset of the enzyme replacement therapy with alglucosidase alfa were compared with follow-up recordings at 12 and 24 months. Brainstem auditory evoked potentials showed a delayed peak I in 1/10 patients and an increased I-III and I-V interpeak latency in 1/10 patients, respectively. The III-V interpeak latencies were in the normal range. Visual evoked potentials were completely normal. Median somatosensory evoked potentials showed an extended interpeak latency in 3/9 patients. Wilcoxon tests comparing age-matched subgroups found significant differences in brainstem auditory evoked potentials and visual evoked potentials. We found that the majority of recordings for evoked potentials were within the ranges for standard values, therefore reflecting the lack of clinically relevant central nervous system involvement. Regular surveillance by means of evoked potentials does not seem to be appropriate in late-onset Pompe patients.

Auditory Detection of the Human Brainstem Auditory Evoked Response.

ERIC Educational Resources Information Center

Kidd, Gerald, Jr.; And Others

1993-01-01

This study evaluated whether listeners can distinguish human brainstem auditory evoked responses elicited by acoustic clicks from control waveforms obtained with no acoustic stimulus when the waveforms are presented auditorily. Detection performance for stimuli presented visually was slightly, but consistently, superior to that which occurred for…

Visual and brainstem auditory evoked potentials in infants with severe vitamin B12 deficiency.

PubMed

Demir, Nihat; Koç, Ahmet; Abuhandan, Mahmut; Calik, Mustafa; Işcan, Akin

2015-01-01

Vitamin B12 plays an important role in the development of mental, motor, cognitive, and social functions via its role in DNA synthesis and nerve myelination. Its deficiency in infants might cause neuromotor retardation as well as megaloblastic anemia. The objective of this study was to investigate the effects of infantile vitamin B12 deficiency on evoked brain potentials and determine whether improvement could be obtained with vitamin B12 replacement at appropriate dosages. Thirty patients with vitamin B12 deficiency and 30 age-matched healthy controls were included in the study. Hematological parameters, visual evoked potentials, and brainstem auditory evoked potentials tests were performed prior to treatment, 1 week after treatment, and 3 months after treatment. Visual evoked potentials (VEPs) and brainstem auditory evoked potentials (BAEPs) were found to be prolonged in 16 (53.3%) and 15 (50%) patients, respectively. Statistically significant improvements in VEP and BAEP examinations were determined 3 months after treatment. Three months after treatment, VEP and BAEP examinations returned to normal in 81.3% and 53.3% of subjects with prolonged VEPs and BAEPs, respectively. These results demonstrate that vitamin B12 deficiency in infants causes significant impairment in the auditory and visual functioning tests of the brain, such as VEP and BAEP.

Evoked potential application to study of echolocation in cetaceans

NASA Astrophysics Data System (ADS)

Supin, Alexander Ya.; Nactigall, Paul E.; Pawloski, Jeffrey; Au, Whitlow W. L.

2002-05-01

The evoked-potential (EP) method is effective in studies of hearing capabilities of cetaceans. However, until now EP studies in cetaceans were performed only in conditions of passive hearing by recording EP to external stimuli. Can this method be applied to study active echolocation in odontocetes? To answer this question, auditory brainstem evoked responses (ABR) were recorded in a false killer whale while the animal echolocated a target within an experiment in which the animal reported the target present or absent. The ABR collection was triggered by echolocation clicks. In these conditions, the recorded ABR pattern contained a duplicate set of waves. A comparison of ABR wave delays recorded during echolocation with those recorded during regular external stimulation has shown that the first set of waves is a response to the emitted click whereas the second one is a response to the echo. Both responses, to the emitted click and to the echo, were of comparable amplitude in spite of the intensity difference of these two sounds of more than 40 dB near the animal's head. This finding indicates some mechanisms releasing responses to echoes from masking by loud emitted clicks. The evoked-potential method may be productive to investigate these mechanisms.

Transcranial electric motor evoked potential monitoring during spine surgery: is it safe?

PubMed

Schwartz, Daniel M; Sestokas, Anthony K; Dormans, John P; Vaccaro, Alexander R; Hilibrand, Alan S; Flynn, John M; Li, P Mark; Shah, Suken A; Welch, William; Drummond, Denis S; Albert, Todd J

2011-06-01

Retrospective review. To report on the safety of repetitive transcranial electric stimulation (RTES) for eliciting motor-evoked potentials during spine surgery. Theoretical concerns over the safety of RTES have hindered broader acceptance of transcranial electric motor-evoked potentials (tceMEP), despite successful implementation of spinal cord monitoring with tceMEPs in many large spine centers, as well as their apparent superiority over mixed-nerve somatosensory-evoked potentials (SSEP) for detection of spinal cord injury. The records of 18,862 consecutive patients who met inclusion criteria and underwent spine surgery with tceMEP monitoring were reviewed for RTES-related complications. This large retrospective review identified only 26 (0.14%) cases with RTES-related complications; all but one of these were tongue lacerations, most of which were self-limiting. The results demonstrate that RTES is a highly safe modality for monitoring spinal cord motor tract function intraoperatively.

Loss of lower limb motor evoked potentials and spinal cord injury during the initial exposure in scoliosis surgery.

PubMed

Legatt, Alan D; Fried, Stephen J; Amaral, Terry D; Sarwahi, Vishal; Moguilevitch, Marina

2014-04-01

To report a case of motor evoked potential changes and spinal cord injury during the initial dissection in scoliosis surgery. Motor evoked potentials to transcranial electrical stimulation were recorded from multiple muscles. Somatosensory evoked potentials to limb nerve stimulation were recorded from the scalp. Clear motor evoked potentials were initially present in all monitored muscles. The patient was then pharmacologically paralyzed for the initial dissection. More than usual bleeding was encountered during that dissection, prompting transfusion. As the neuromuscular blockade subsided, motor evoked potentials persisted in the hand muscles but disappeared and remained absent in all monitored leg muscles. The spine had not been instrumented. A wake-up test demonstrated paraplegia; the surgery was aborted. There were no adverse somatosensory evoked potential changes. MRI showed an anterior spinal cord infarct. Copious soft tissue bleeding during the initial dissection might have lowered pressures in critical segmental arteries enough to cause spinal cord infarction through a steal phenomenon. The lack of somatosensory evoked potential changes reflected sparing of the dorsal columns. When neuromuscular blockade is used during the initial soft tissue dissection, motor evoked potentials should be assessed after this, but before spinal instrumentation, to determine whether there had been any spinal cord compromise during the initial dissection.

Intraoperative changes in transcranial motor evoked potentials and somatosensory evoked potentials predicting outcome in children with intramedullary spinal cord tumors.

PubMed

Cheng, Jason S; Ivan, Michael E; Stapleton, Christopher J; Quinones-Hinojosa, Alfredo; Gupta, Nalin; Auguste, Kurtis I

2014-06-01

Intraoperative dorsal column mapping, transcranial motor evoked potentials (TcMEPs), and somatosensory evoked potentials (SSEPs) have been used in adults to assist with the resection of intramedullary spinal cord tumors (IMSCTs) and to predict postoperative motor deficits. The authors sought to determine whether changes in MEP and SSEP waveforms would similarly predict postoperative motor deficits in children. The authors reviewed charts and intraoperative records for children who had undergone resection for IMSCTs as well as dorsal column mapping and TcMEP and SSEP monitoring. Motor evoked potential data were supplemented with electromyography data obtained using a Kartush microstimulator (Medtronic Inc.). Motor strength was graded using the Medical Research Council (MRC) scale during the preoperative, immediate postoperative, and follow-up periods. Reductions in SSEPs were documented after mechanical traction, in response to maneuvers with the cavitational ultrasonic surgical aspirator (CUSA), or both. Data from 12 patients were analyzed. Three lesions were encountered in the cervical and 7 in the thoracic spinal cord. Two patients had lesions of the cervicomedullary junction and upper spinal cord. Intraoperative MEP changes were noted in half of the patients. In these cases, normal polyphasic signals converted to biphasic signals, and these changes correlated with a loss of 1-2 grades in motor strength. One patient lost MEP signals completely and recovered strength to MRC Grade 4/5. The 2 patients with high cervical lesions showed neither intraoperative MEP changes nor motor deficits postoperatively. Dorsal columns were mapped in 7 patients, and the midline was determined accurately in all 7. Somatosensory evoked potentials were decreased in 7 patients. Two patients each had 2 SSEP decreases in response to traction intraoperatively but had no new sensory findings postoperatively. Another 2 patients had 3 traction-related SSEP decreases intraoperatively, and both

The effect of changes in stimulus level on electrically evoked cortical auditory potentials.

PubMed

Kim, Jae-Ryong; Brown, Carolyn J; Abbas, Paul J; Etler, Christine P; O'Brien, Sara

2009-06-01

The purpose of this study was to determine whether the electrically evoked acoustic change complex (EACC) could be used to assess sensitivity to changes in stimulus level in cochlear implant (CI) recipients and to investigate the relationship between EACC amplitude and rate of growth of the N1-P2 onset response with increases in stimulus level. Twelve postlingually deafened adults using Nucleus CI24 CIs participated in this study. Nucleus Implant Communicator (NIC) routines were used to bypass the speech processor and to control the stimulation of the implant directly. The stimulus consisted of an 800 msec burst of a 1000 pps biphasic pulse train. A change in the stimulus level was introduced 400 msec after stimulus onset. Band-pass filtering (1 to 100 Hz) was used to minimize stimulus artifact. Four to six recordings of 50 sweeps were obtained for each condition, and averaged responses were analyzed in the time domain using standard peak picking procedures. Cortical auditory change potentials were recorded from CI users in response to both increases and decreases in stimulation level. The amplitude of the EACC was found to be dependent on the magnitude of the stimulus change. Increases in stimulus level elicited more robust EACC responses than decreases in stimulus level. Also, EACC amplitudes were significantly correlated with the slope of the growth of the onset response. This work describes the effect of change in stimulus level on electrically evoked auditory change potentials in CI users. The amplitude of the EACC was found to be related both to the magnitude of the stimulus change introduced and to the rate of growth of the N1-P2 onset response. To the extent that the EACC reflects processing of stimulus change, it could potentially be a valuable tool for assessing neural processing of the kinds of stimulation patterns produced by a CI. Further studies are needed, however, to determine the relationships between the EACC and psychophysical measures of

NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.

PubMed

Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M

2015-01-21

A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 Gαq and egl-8 PLCβ) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 Gαq and egl-8 PLCβ and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. Copyright © 2015 the authors 0270-6474/15/351038-05$15.00/0.

Sunlight irradiance and habituation of visual evoked potentials in migraine: The environment makes its mark.

PubMed

Lisicki, Marco; D'Ostilio, Kevin; Erpicum, Michel; Schoenen, Jean; Magis, Delphine

2017-01-01

Background Migraine is a complex multifactorial disease that arises from the interaction between a genetic predisposition and an enabling environment. Habituation is considered as a fundamental adaptive behaviour of the nervous system that is often impaired in migraine populations. Given that migraineurs are hypersensitive to light, and that light deprivation is able to induce functional changes in the visual cortex recognizable through visual evoked potentials habituation testing, we hypothesized that regional sunlight irradiance levels could influence the results of visual evoked potentials habituation studies performed in different locations worldwide. Methods We searched the literature for visual evoked potentials habituation studies comparing healthy volunteers and episodic migraine patients and correlated their results with levels of local solar radiation. Results After reviewing the literature, 26 studies involving 1291 participants matched our inclusion criteria. Deficient visual evoked potentials habituation in episodic migraine patients was reported in 19 studies. Mean yearly sunlight irradiance was significantly higher in locations of studies reporting deficient habituation. Correlation analyses suggested that visual evoked potentials habituation decreases with increasing sunlight irradiance in migraine without aura patients. Conclusion Results from this hypothesis generating analysis suggest that variations in sunlight irradiance may induce adaptive modifications in visual processing systems that could be reflected in visual evoked potentials habituation, and thus partially account for the difference in results between studies performed in geographically distant centers. Other causal factors such as genetic differences could also play a role, and therefore well-designed prospective trials are warranted.

On hemispheric differences in evoked potentials to speech stimuli

NASA Technical Reports Server (NTRS)

Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

1975-01-01

Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

[Motor evoked potentials in thoracoabdominal aortic surgery].

PubMed

Magro, Cátia; Nora, David; Marques, Miguel; Alves, Angela Garcia

2012-01-01

Thoracoabdominal aortic disease (aneurysm or dissection) has increased in recent decades. Surgery is the curative treatment but is associated to high perioperative morbidity and mortality risks. Paraplegia is one of the most severe complications, whose incidence has decreased significantly with the implementation of spinal cord protection strategies. No single method or combination of methods has proven to be fully effective in preventing paraplegia. This review is intended to analyse the scientific evidence available on the role of intraoperative monitoring with motor evoked potentials in the neurological outcome of patients undergoing thoracoabdominal aortic surgery. An online search (PubMed) was conducted. Relevant references were selected and reviewed. Intraoperative monitoring with motor evoked potentials (MEP) allows early detection of ischemic events and a targeted intervention to prevent the development of spinal cord injury, significantly reducing the incidence of postoperative paraplegia. MEP monitoring may undergo several intraoperative interferences which may compromise their interpretation. Neuromuscular blockade is the main limiting factor of anesthetic origin. It is essential to strike a balance between monitoring conditions and surgical and anesthetic needs as well as to evaluate the risks and benefits of the technique for each patient. MEP monitoring improves neurological outcome when integrated in a multidisciplinary strategy which must include multiple protective mechanisms that should be tailored to each hospital reality.

Vertex evoked potentials in a rating-scale detection task: Relation to signal probability

NASA Technical Reports Server (NTRS)

Squires, K. C.; Squires, N. K.; Hillyard, S. A.

1974-01-01

Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal.

Stability of Evoked Potentials during Auditory Attention

DTIC Science & Technology

1988-12-01

attention ef- (S2), to which the subject made a behavioral response and fects upon NI components of the evoked potential received food reinforcement for a... food dipper mounted in the floor, and a driver, with a sound tube attached, mounted in the top of the box. Histology Four weeks after surgery, the cats...response paradigm dose of intravenous sodium pentobarbital. Electrolytic lesions were using food reinforcement. They were gradually deprived of food

Human auditory evoked potentials in the assessment of brain function during major cardiovascular surgery.

PubMed

Rodriguez, Rosendo A

2004-06-01

Focal neurologic and intellectual deficits or memory problems are relatively frequent after cardiac surgery. These complications have been associated with cerebral hypoperfusion, embolization, and inflammation that occur during or after surgery. Auditory evoked potentials, a neurophysiologic technique that evaluates the function of neural structures from the auditory nerve to the cortex, provide useful information about the functional status of the brain during major cardiovascular procedures. Skepticism regarding the presence of artifacts or difficulty in their interpretation has outweighed considerations of its potential utility and noninvasiveness. This paper reviews the evidence of their potential applications in several aspects of the management of cardiac surgery patients. The sensitivity of auditory evoked potentials to the effects of changes in brain temperature makes them useful for monitoring cerebral hypothermia and rewarming during cardiopulmonary bypass. The close relationship between evoked potential waveforms and specific anatomic structures facilitates the assessment of the functional integrity of the central nervous system in cardiac surgery patients. This feature may also be relevant in the management of critical patients under sedation and coma or in the evaluation of their prognosis during critical care. Their objectivity, reproducibility, and relative insensitivity to learning effects make auditory evoked potentials attractive for the cognitive assessment of cardiac surgery patients. From a clinical perspective, auditory evoked potentials represent an additional window for the study of underlying cerebral processes in healthy and diseased patients. From a research standpoint, this technology offers opportunities for a better understanding of the particular cerebral deficits associated with patients who are undergoing major cardiovascular procedures.

Auditory evoked potential could reflect emotional sensitivity and impulsivity

PubMed Central

Kim, Ji Sun; Kim, Sungkean; Jung, Wookyoung; Im, Chang-Hwan; Lee, Seung-Hwan

2016-01-01

Emotional sensitivity and impulsivity could cause interpersonal conflicts and neuropsychiatric problems. Serotonin is correlated with behavioral inhibition and impulsivity. This study evaluated whether the loudness dependence of auditory evoked potential (LDAEP), a potential biological marker of central serotonergic activity, could reflect emotional sensitivity and impulsivity. A total of 157 healthy individuals were recruited, who performed LDAEP and Go/Nogo paradigms during electroencephalogram measurement. Barratt impulsivity scale (BIS), Conners’ Adult ADHD rating scale (CAARS), and affective lability scale (ALS) were evaluated. Comparison between low and high LDAEP groups was conducted for behavioural, psychological, and event-related potential (ERP) measures. The high LDAEP group showed significantly increased BIS, a subscale of the CAARS, ALS, and false alarm rate of Nogo stimuli compared to the low LDAEP group. LDAEP showed significant positive correlations with the depression scale, ALS scores, subscale of the CAARS and Nogo-P3 amplitude. In the source activity of Nogo-P3, the cuneus, lingual gyrus, and precentral gyrus activities were significantly increased in the high LDAEP group. Our study revealed that LDAEP could reflect emotional sensitivity and impulsivity. LDAEP, an auditory evoked potential could be a useful tool to evaluate emotional regulation. PMID:27910865

Short latency vestibular evoked potentials in the chicken embryo

NASA Technical Reports Server (NTRS)

Jones, S. M.; Jones, T. A.

1996-01-01

Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies < 6.0 ms) were scored and latencies and amplitudes quantified. Vestibular response latencies were significantly longer (P < 0.01) and amplitudes significantly smaller (P < 0.001) than those observed in 2-week-old birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P < 0.03) than those observed in 2-week-old birds (-23.0dBre 1.0 g/ms). Latency/intensity functions (that is, slopes) were not significantly different between embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P < 0.001). We presume that these differences reflect the refinement of sensory function that occurs following 19 to 20 days of incubation. The recording of vestibular evoked potentials provides an objective, direct and noninvasive measure of peripheral vestibular function in the embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

The Relationship of Visual Evoked Potential Asymmetries to the Performance of Sonar Operators

DTIC Science & Technology

1981-08-11

also been related to EP variability. Schizophrenic adults and patients with Korsakoff’s Syndrome have shown higher evoked potential variability than...average evoked response in Korsakoff patients. J. Psychiatry Res. 6: 253-260, 1969. Santoro, T. and D. Fender. Rules for the perception of

[Effects of sevoflurane and propofol on evoked potentials during neurosurgical anesthesia].

PubMed

Nakagawa, Itsuo; Hidaka, Syozo; Okada, Hironori; Kubo, Takashi; Okamura, Kenta; Kato, Takahiro

2006-06-01

The effect of anesthetics on somatosensory evoked potential (SEP) and auditory brain stem response (ABR) has been a subject of intense reseach over the last two decades. In fact, volatile anesthetics have been repeatedly shown to decrease cortical amplitude in a dose-dependent fashion but the information regarding the effect of propofol is incomplete. The purpose of this study was to compare the effects of sevoflurane and propofol on evoked potentials during comparable depth of anesthesia guided by bispectral index (BIS). Forty four patients scheduled for neurosurgery were studied. Anesthesia was maintained with intravenous propofol using target controlled infusion (TCI). We measured the change of amplitude and latency of SEP(N20-P25), ABR (V wave) and visual evoked potential (VEP: P100) at three sets of sevoflurane (0%, 1%, 2%) or propofol concentrations (effect site concentration of 1.5, 2.0, 3.0 microug x ml(-1)). BIS monitor was used to measure relative depth of hypnosis. With increasing concentrations of sevoflurane (0, 1% and 2%), SEP showed dose-related reduction in its amplitude, ABR produced less marked changes and VEP showed a significant reduction at 1%. VEP at the propofol concentration of 3.0 microg x ml(-1) was decreased significantly compared with the amplitude at 1.5 microg x ml(-1) concentration. No significant change was observed with SEP and ABR during the change of propofol dosages. BIS values were almost the same with each anesthetics. VEP was most strongly affected with anesthetics, and ABR showed less marked influence of sevoflurane and propofol. Propofol based TIVA technique would induce less change in evoked potentials than sevoflurane.

Automatic classification of visual evoked potentials based on wavelet decomposition

NASA Astrophysics Data System (ADS)

Stasiakiewicz, Paweł; Dobrowolski, Andrzej P.; Tomczykiewicz, Kazimierz

2017-04-01

Diagnosis of part of the visual system, that is responsible for conducting compound action potential, is generally based on visual evoked potentials generated as a result of stimulation of the eye by external light source. The condition of patient's visual path is assessed by set of parameters that describe the time domain characteristic extremes called waves. The decision process is compound therefore diagnosis significantly depends on experience of a doctor. The authors developed a procedure - based on wavelet decomposition and linear discriminant analysis - that ensures automatic classification of visual evoked potentials. The algorithm enables to assign individual case to normal or pathological class. The proposed classifier has a 96,4% sensitivity at 10,4% probability of false alarm in a group of 220 cases and area under curve ROC equals to 0,96 which, from the medical point of view, is a very good result.

[Evoked potentials extraction based on cross-talk resistant adaptive noise cancellation].

PubMed

Zeng, Qingning; Li, Ling; Liu, Qinghua; Yao, Dezhong

2004-06-01

As Evoked Potentials are much lower in amplitude with respect to the on-going EEC, many trigger-related signals are needed for common averaging technique to enable the extraction of single-trail evoked potentials (EP). How to acquire EP through fewer evocations is an important research project. This paper proposes a cross-talk resistant adaptive noise cancellation method to extract EP. Together with the use of filtering technique and the common averaging technique, the present method needs much less evocations to acquire EP signals. According to the simulating experiment, it needs only several evocations or even only one evocation to get EP signals in good quality.

The steady-state visual evoked potential in vision research: A review

PubMed Central

Norcia, Anthony M.; Appelbaum, L. Gregory; Ales, Justin M.; Cottereau, Benoit R.; Rossion, Bruno

2015-01-01

Periodic visual stimulation and analysis of the resulting steady-state visual evoked potentials were first introduced over 80 years ago as a means to study visual sensation and perception. From the first single-channel recording of responses to modulated light to the present use of sophisticated digital displays composed of complex visual stimuli and high-density recording arrays, steady-state methods have been applied in a broad range of scientific and applied settings.The purpose of this article is to describe the fundamental stimulation paradigms for steady-state visual evoked potentials and to illustrate these principles through research findings across a range of applications in vision science. PMID:26024451

Influence of rotating shift work on visual reaction time and visual evoked potential.

PubMed

R V, Hemamalini; N, Krishnamurthy; A, Saravanan

2014-10-01

The present day life style is changing the circadian rhythm of the body especially in rotating night shift workers. The impact of this prolongs their reaction time. Night shift also interferes with the circadian variation of pupil size which may affect the visual evoked potential. To compare the visual reaction time, visual evoked potential (VEP) in rotating night shift workers & day workers and also to correlate the changes in visual reaction time with visual evoked potential. Forty healthy male security guards & staff (25 - 35 y) who did rotating night shifts at least for six months & 40 d workers (25 - 35 y) who did not do night shift in last two years were involved in the study. Visual reaction time and the latency & amplitude of VEP were recorded. Kolmogorov- Smirnov test for normalcy showed the latencies & amplitude of VEP to be normally distributed. Student's unpaired t test showed significant difference (p<0.05) in the visual time and in the latencies of VEP between night shift & day workers. There was no significant difference in the amplitude of VEP. Night shift workers who are prone to circadian rhythm alteration will have prolonged visual reaction time & visual evoked potential abnormalities. Implementation of Bright Light Therapy would be beneficial to the night shift worker.

Non-provocative diagnostics of photosensitivity using visual evoked potentials.

PubMed

Vermeulen, Joost; Kalitzin, Stiliyan; Parra, Jaime; Dekker, Erwin; Vossepoel, Albert; da Silva, Fernando Lopes

2008-04-01

Photosensitive epilepsy (PSE) is the most common form of reflex epilepsy. Usually, to find out whether a patient is sensitive, he/she is stimulated visually with, e.g. a stroboscopic light stimulus at variable frequency and intensity until a photo paroxysmal response (PPR) occurs. The research described in this work aims to find whether photosensitivity can be detected without provoking a PPR. Twenty-two subjects, 15 with known photosensitivity, were stimulated with visual stimuli that did not provoke a PPR. Using an "evoked response representation", 18 features were analytically derived from EEG signals. Single- and multi-feature classification paradigms were applied to extract those features that separate best subjects with PSE from controls. Two variables in the "evoked response representation", a frequency term and a goodness of fit term to a particular template, appeared to be best suited to make a prediction about the photosensitivity of a subject. Evoked responses appear to carry information about potential PSE. This result can be useful for screening patients for photosensitivity and it may also help to assess in a quantitative way the effectiveness of medical therapy.

Exploring brainstem function in multiple sclerosis by combining brainstem reflexes, evoked potentials, clinical and MRI investigations.

PubMed

Magnano, Immacolata; Pes, Giovanni Mario; Pilurzi, Giovanna; Cabboi, Maria Paola; Ginatempo, Francesca; Giaconi, Elena; Tolu, Eusebio; Achene, Antonio; Salis, Antonio; Rothwell, John C; Conti, Maurizio; Deriu, Franca

2014-11-01

To investigate vestibulo-masseteric (VMR), acoustic-masseteric (AMR), vestibulo-collic (VCR) and trigemino-collic (TCR) reflexes in patients with multiple sclerosis (MS); to relate abnormalities of brainstem reflexes (BSRs) to multimodal evoked potentials (EPs), clinical and Magnetic Resonance Imaging (MRI) findings. Click-evoked VMR, AMR and VCR were recorded from active masseter and sternocleidomastoid muscles, respectively; TCR was recorded from active sternocleidomastoid muscles, following electrical stimulation of the infraorbital nerve. EPs and MRI were performed with standard techniques. Frequencies of abnormal BSRs were: VMR 62.1%, AMR 55.1%, VCR 25.9%, TCR 58.6%. Brainstem dysfunction was identified by these tests, combined into a four-reflex battery, in 86.9% of cases, by EPs in 82.7%, MRI in 71.7% and clinical examination in 37.7% of cases. The sensitivity of paired BSRs/EPs (93.3%) was significantly higher than combined MRI/clinical testing (70%) in patients with disease duration ⩽6.4years. BSR alterations significantly correlated with clinical, EP and MRI findings. The four-BSR battery effectively increases the performance of standard EPs in early detection of brainstem impairment, otherwise undetected by clinical examination and neuroimaging. Multiple BSR assessment usefully supplements conventional testing and monitoring of brainstem function in MS, especially in newly diagnosed patients. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Development of visual evoked potentials in neonates. A study using light emitting diode goggles.

PubMed Central

Chin, K C; Taylor, M J; Menzies, R; Whyte, H

1985-01-01

We used a signal averager with light emitting diode goggles as the photostimulator to study the development of the visual evoked potentials in 40 normal neonates of between 23 and 42 weeks' gestation. All except two infants of less than 24 weeks' gestation had replicable visual evoked potentials. A negative peak of latency (mean (SD), 308 (21) msec) was present in all infants, but the development of the primary positive peak depended on maturity. Only infants of 37 weeks or more had a consistent positive peak of latency (mean (SD), 220 (22) msec). The practical simplicity and reliability of this technique has distinct advantages over previous conventional recording systems. Neonatal visual evoked potentials are shown to change with maturity. PMID:4091582

Evoked potentials in immobilized cats to a combination of clicks with painful electrocutaneous stimuli

NASA Technical Reports Server (NTRS)

Gilinskiy, M. A.; Korsakov, I. A.

1979-01-01

Averaged evoked potentials in the auditory, somatosensory, and motor cortical zones, as well as in the mesencephalic reticular formation were recorded in acute experiments on nonanesthetized, immobilized cats. Omission of the painful stimulus after a number of pairings resulted in the appearance of a delayed evoked potential, often resembling the late phases of the response to the painful stimulus. The characteristics of this response are discussed in comparison with conditioned changes of the sensory potential amplitudes.

ROLE OF NMDA, NICOTINIC, AND GABA RECEPTORS IN THE STEADY STATE VISUAL EVOKED POTENTIAL IN RATS.

EPA Science Inventory

This manuscript characterizes the receptor pathways involved in pattern-evoked potential generation in rats

" NMDA and nicotinic acetylcholine receptors appear to be involved in the generation of the steady-state pattern evoked response in vivo.

" The pattern evok...

Effect of ischaemia on somatosensory evoked potentials in diabetic patients.

PubMed Central

López-Alburquerque, T; García Miguel, A; Ruiz Ezquerro, J J; de Portugal Alvarez, J

1987-01-01

The nerve action potential at the elbow and somatosensory evoked potentials (SEPs) at the scalp were recorded over 30 minutes of tourniquet-induced limb ischaemia in 10 diabetic patients and 10 controls. According to the SEP changes, an increased resistance to nerve ischaemia in diabetic patients was observed. The pathways involved in SEP conduction are discussed. PMID:3585354

An indirect component in the evoked compound action potential of the vagal nerve.

PubMed

Ordelman, Simone C M A; Kornet, Lilian; Cornelussen, Richard; Buschman, Hendrik P J; Veltink, Peter H

2010-12-01

The vagal nerve plays a vital role in the regulation of the cardiovascular system. It not only regulates the heart but also sends sensory information from the heart back to the brain. We hypothesize that the evoked vagal nerve compound action potential contains components that are indirect via the brain stem or coming via the neural network on the heart. In an experimental study of 15 pigs, we identified four components in the evoked compound action potentials. The fourth component was found to be an indirect component, which came from the periphery. The latency of the indirect component increased when heart rate and contractility were decreased by burst stimulation (P = 0.01; n = 7). When heart rate and contractility were increased by dobutamine administration, the latency of the indirect component decreased (P = 0.01; n = 9). This showed that the latency of the indirect component of the evoked compound action potentials may relate to the state of the cardiovascular system.

Toward Optimizing Vestibular Evoked Myogenic Potentials: Normalization Reduces the Need for Strong Neck Muscle Contraction.

PubMed

Noij, Kimberley S; Herrmann, Barbara S; Rauch, Steven D; Guinan, John J

2017-01-01

The cervical vestibular evoked myogenic potential (cVEMP) represents an inhibitory reflex of the saccule measured in the ipsilateral sternocleidomastoid muscle (SCM) in response to acoustic or vibrational stimulation. Since the cVEMP is a modulation of SCM electromyographic (EMG) activity, cVEMP amplitude is proportional to muscle EMG amplitude. We sought to evaluate muscle contraction influences on cVEMP peak-to-peak amplitudes (VEMPpp), normalized cVEMP amplitudes (VEMPn), and inhibition depth (VEMPid). cVEMPs at 500 Hz were measured in 25 healthy subjects for 3 SCM EMG contraction ranges: 45-65, 65-105, and 105-500 μV root mean square (r.m.s.). For each range, we measured cVEMP sound level functions (93-123 dB peSPL) and sound off, meaning that muscle contraction was measured without acoustic stimulation. The effect of muscle contraction amplitude on VEMPpp, VEMPn, and VEMPid and the ability to distinguish cVEMP presence/absence were evaluated. VEMPpp amplitudes were significantly greater at higher muscle contractions. In contrast, VEMPn and VEMPid showed no significant effect of muscle contraction. Cohen's d indicated that for all 3 cVEMP metrics contraction amplitude variations produced little change in the ability to distinguish cVEMP presence/absence. VEMPid more clearly indicated saccular output because when no acoustic stimulus was presented the saccular inhibition estimated by VEMPid was zero, unlike those by VEMPpp and VEMPn. Muscle contraction amplitude strongly affects VEMPpp amplitude, but contractions 45-300 μV r.m.s. produce stable VEMPn and VEMPid values. Clinically, there may be no need for subjects to exert high contraction effort. This is especially beneficial in patients for whom maintaining high SCM contraction amplitudes is challenging. © 2018 S. Karger AG, Basel.

Axono-cortical evoked potentials: A proof-of-concept study.

PubMed

Mandonnet, E; Dadoun, Y; Poisson, I; Madadaki, C; Froelich, S; Lozeron, P

2016-04-01

Awake surgery is currently considered the best method to tailor intraparenchymatous resections according to functional boundaries. However, the exact mechanisms by which electrical stimulation disturbs behavior remain largely unknown. In this case report, we describe a new method to explore the propagation toward cortical sites of a brief pulse applied to an eloquent white matter pathway. We present a patient, operated on in awake condition for removal of a cavernoma of the left ventral premotor cortex. At the end of the resection, the application of 60Hz stimulation in the white matter of the operculum induced anomia. Stimulating the same site at a frequency of 1Hz during 70seconds allowed to record responses on electrodes put over Broca's area and around the inferior part of central sulcus. Axono-cortical evoked potentials were then obtained by averaging unitary responses, time-locked to the stimulus. We then discuss the origin of these evoked axono-cortical potentials and the likely pathway connecting the stimulation site to the recorded cortical sites. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Laser-evoked potentials in painful radiculopathy.

PubMed

Hüllemann, P; von der Brelie, C; Manthey, G; Düsterhöft, J; Helmers, A K; Synowitz, M; Gierthmühlen, J; Baron, R

2017-11-01

The aims of this exploratory study were (1) to develop a standardized objective electrophysiological technique with laser-evoked potentials to assess dorsal root damage quantitatively and (2) to correlate these LEP measures with clinical parameters and sensory abnormalities (QST) in the affected dermatome. Thirty-eight patients with painful radiculopathy and 20 healthy subjects were investigated with LEP recorded from the affected dermatome and control areas as well as with quantitative sensory testing. Questionnaires evaluating severity and functionality were applied. On average, LEP amplitudes and latencies from the affected dermatomes did not differ from the contralateral control side. In patients with left L5 radiculopathy (more severely affected) the N2 latency was longer and the amplitudes reduced. The N2P2 amplitude correlated with pinprick evoked sensations in QST. The N2 latency from the affected dermatome correlates with pain intensity, chronicity, clinical severity and with a decrease of physical function. An increase in N2-latency indicates a more pronounced nerve root damage, which is associated with a decrease of function and an increase of severity and pain. LEP amplitudes are associated with the functional status of the nociceptive system and may distinguish between degeneration of neuronal systems and central sensitization processes. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Correlation between caloric and ocular vestibular evoked myogenic potential test results.

PubMed

Huang, Chi-Hsuan; Wang, Shou-Jen; Young, Yi-Ho

2012-02-01

The ocular vestibular evoked myogenic potential (o-VEMP) test results correlate significantly with caloric test results for patients with acoustic neuroma (AN), but not for patients with Meniere's disease (MD), indicating that the o-VEMP test may replace the caloric test for evaluating the vestibular nerve from which the AN arises. Conversely, the caloric, o-VEMP, and cervical VEMP (c-VEMP) tests should be performed to map lesion sites in the vestibular labyrinth. This study performed caloric, o-VEMP, and c-VEMP tests on patients with central and peripheral vestibular disorders to investigate their relationships. In all, 66 patients comprising 16 with unilateral AN and 50 with unilateral definite MD were enrolled. All patients underwent caloric, o-VEMP, and c-VEMP tests. In the AN group, the caloric test identified canal paresis and caloric areflexia in 10 ears, while the o-VEMP and c-VEMP tests identified abnormal (absent or delayed) responses in 12 and 11 ears, respectively. A significant correlation existed between caloric and o-VEMP test results, but not between caloric and c-VEMP test results, or between o-VEMP and c-VEMP test results. For the MD group, abnormal caloric, o-VEMP, and c-VEMP test results were obtained for 24%, 44%, and 38% of hydropic ears, respectively. No correlation existed between any two test results.

Brainstem auditory and somatosensory evoked potentials in relation to clinical and neuroimaging findings in Chiari type 1 malformation.

PubMed

Moncho, Dulce; Poca, Maria-Antonia; Minoves, Teresa; Ferré, Alejandro; Rahnama, Kimia; Sahuquillo, Juan

2015-04-01

The aim of this study was to describe the abnormalities found in the recordings of evoked potentials (EPs), in particular those of brainstem auditory evoked potentials and somatosensory evoked potentials, in a homogeneous series of patients with Chiari type 1 malformation (CM-1) and study their relationship with clinical symptoms and malformation severity. CM-1 is characterized by cerebellar tonsils that descend below the foramen magnum and may be associated with EP alterations. However, only a small number of authors have described these tests in CM-1, and the patient groups studied to date have been small and heterogeneous. The clinical findings, neuroimages, and EP findings were retrospectively studied in a cohort of 50 patients with CM-1. Seventy percent of patients had EP abnormalities (brainstem auditory evoked potential: 52%, posterior tibial nerve somatosensory evoked potential: 42%, and median nerve somatosensory evoked potential: 34%). The most frequent alteration was an increased central conduction time. Morphometric measurements differed between the normal and pathological groups, although no statistical significance was found when comparing these groups. A high percentage of patients with CM-1 show EP alterations regardless of their clinical or radiological findings, thus highlighting the necessity of performing these tests, especially in patients with few or no symptoms.

Visual evoked potential in RCS rats with Okayama University-type retinal prosthesis (OUReP™) implantation.

PubMed

Alamusi; Matsuo, Toshihiko; Hosoya, Osamu; Uchida, Tetsuya

2017-06-01

Photoelectric dye-coupled polyethylene film, designated Okayama University type-retinal prosthesis or OUReP™, generates light-evoked surface electric potentials and stimulates neurons. The dye-coupled films or plain films were implanted subretinally in both eyes of 10 Royal College of Surgeons rats with hereditary retinal dystrophy at the age of 6 weeks. Visual evoked potentials in response to monocular flashing light stimuli were recorded from cranially-fixed electrodes, 4 weeks and 8 weeks after the implantation. After the recording, subretinal film implantation was confirmed histologically in 7 eyes with dye-coupled films and 7 eyes with plain films. The recordings from these 7 eyes in each group were used for statistical analysis. The amplitudes of visual evoked potentials in the consecutive time points from 125 to 250 ms after flash were significantly larger in the 7 eyes with dye-coupled film implantation, compared to the 7 eyes with plain film implantation at 8 weeks after the implantation (P < 0.05, repeated-measure ANOVA). The photoelectric dye-coupled polyethylene film, as retinal prosthesis, gave rise to visual evoked potential in response to flashing light.

Cellular generators of the cortical auditory evoked potential initial component.

PubMed

Steinschneider, M; Tenke, C E; Schroeder, C E; Javitt, D C; Simpson, G V; Arezzo, J C; Vaughan, H G

1992-01-01

Cellular generators of the initial cortical auditory evoked potential (AEP) component were determined by analyzing laminar profiles of click-evoked AEPs, current source density, and multiple unit activity (MUA) in primary auditory cortex of awake monkeys. The initial AEP component is a surface-negative wave, N8, that peaks at 8-9 msec and inverts in polarity below lamina 4. N8 is generated by a lamina 4 current sink and a deeper current source. Simultaneous MUA is present from lower lamina 3 to the subjacent white matter. Findings indicate that thalamocortical afferents are a generator of N8 and support a role for lamina 4 stellate cells. Relationships to the human AEP are discussed.

Characterization of Motor and Somatosensory Evoked Potentials in the Yucatan Micropig Using Transcranial and Epidural Stimulation.

PubMed

Benavides, Francisco D; Santamaria, Andrea J; Bodoukhin, Nikita; Guada, Luis G; Solano, Juan P; Guest, James D

2017-09-15

Yucatan micropigs have brain and spinal cord dimensions similar to humans and are useful for certain spinal cord injury (SCI) translational studies. Micropigs are readily trained in behavioral tasks, allowing consistent testing of locomotor loss and recovery. However, there has been little description of their motor and sensory pathway neurophysiology. We established methods to assess motor and sensory cortical evoked potentials in the anesthetized, uninjured state. We also evaluated epidurally evoked motor and sensory stimuli from the T6 and T9 levels, spanning the intended contusion injury epicenter. Response detection frequency, mean latency and amplitude values, and variability of evoked potentials were determined. Somatosensory evoked potentials were reliable and best detected during stimulation of peripheral nerve and epidural stimulation by referencing the lateral cortex to midline Fz. The most reliable hindlimb motor evoked potential (MEP) occurred in tibialis anterior. We found MEPs in forelimb muscles in response to thoracic epidural stimulation likely generated from propriospinal pathways. Cranially stimulated MEPs were easier to evoke in the upper limbs than in the hindlimbs. Autopsy studies revealed substantial variations in cortical morphology between animals. This electrophysiological study establishes that neurophysiological measures can be reliably obtained in micropigs in a time frame compatible with other experimental procedures, such as SCI and transplantation. It underscores the need to better understand the motor control pathways, including the corticospinal tract, to determine which therapeutics are suitable for testing in the pig model.

Brainstem Auditory Evoked Potential Study in Children with Autistic Disorder.

ERIC Educational Resources Information Center

Wong, Virginia; Wong, Sik Nin

1991-01-01

Brainstem auditory evoked potentials were compared in 109 children with infantile autism, 38 with autistic condition, 19 with mental retardation, and 20 normal children. Children with infantile autism or autistic condition had significantly longer brainstem transmission time than normal children suggesting neurological damage as the basis of…

Tone-Evoked Acoustic Change Complex (ACC) Recorded in a Sedated Animal Model.

PubMed

Presacco, Alessandro; Middlebrooks, John C

2018-05-10

The acoustic change complex (ACC) is a scalp-recorded cortical evoked potential complex generated in response to changes (e.g., frequency, amplitude) in an auditory stimulus. The ACC has been well studied in humans, but to our knowledge, no animal model has been evaluated. In particular, it was not known whether the ACC could be recorded under the conditions of sedation that likely would be necessary for recordings from animals. For that reason, we tested the feasibility of recording ACC from sedated cats in response to changes of frequency and amplitude of pure-tone stimuli. Cats were sedated with ketamine and acepromazine, and subdermal needle electrodes were used to record electroencephalographic (EEG) activity. Tones were presented from a small loudspeaker located near the right ear. Continuous tones alternated at 500-ms intervals between two frequencies or two levels. Neurometric functions were created by recording neural response amplitudes while systematically varying the magnitude of steps in frequency centered in octave frequency around 2, 4, 8, and 16 kHz, all at 75 dB SPL, or in decibel level around 75 dB SPL tested at 4 and 8 kHz. The ACC could be recorded readily under this ketamine/azepromazine sedation. In contrast, ACC could not be recorded reliably under any level of isoflurane anesthesia that was tested. The minimum frequency (expressed as Weber fractions (df/f)) or level steps (expressed in dB) needed to elicit ACC fell in the range of previous thresholds reported in animal psychophysical tests of discrimination. The success in recording ACC in sedated animals suggests that the ACC will be a useful tool for evaluation of other aspects of auditory acuity in normal hearing and, presumably, in electrical cochlear stimulation, especially for novel stimulation modes that are not yet feasible in humans.

Effect of caffeine on vestibular evoked myogenic potential: a systematic review with meta-analysis.

PubMed

Souza, Maria Eduarda Di Cavalcanti Alves de; Costa, Klinger Vagner Teixeira da; Menezes, Pedro de Lemos

2017-12-24

Caffeine can be considered the most consumed drug by adults worldwide, and can be found in several foods, such as chocolate, coffee, tea, soda and others. Overall, caffeine in moderate doses, results in increased physical and intellectual productivity, increases the capacity of concentration and reduces the time of reaction to sensory stimuli. On the other hand, high doses can cause noticeable signs of mental confusion and error induction in intellectual tasks, anxiety, restlessness, muscle tremors, tachycardia, labyrinthine changes, and tinnitus. Considering that the vestibular evoked myogenic potential is a clinical test that evaluates the muscular response of high intensity auditory stimulation, the present systematic review aimed to analyze the effects of caffeine on vestibular evoked myogenic potential. This study consisted of the search of the following databases: MEDLINE, CENTRAL, ScienceDirect, Scopus, Web of Science, LILACS, SciELO and ClinicalTrials.gov. Additionally, the gray literature was also searched. The search strategy included terms related to intervention (caffeine or coffee consumption) and the primary outcome (vestibular evoked myogenic potential). Based on the 253 potentially relevant articles identified through the database search, only two full-text publications were retrieved for further evaluation, which were maintained for qualitative analysis. Analyzing the articles found, caffeine has no effect on vestibular evoked myogenic potential in normal individuals. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Influence of detomidine and buprenorphine on motor-evoked potentials in horses.

PubMed

Nollet, H; Van Ham, L; Gasthuys, F; Dewulf, J; Vanderstraeten, G; Deprez, P

2003-04-26

Horses need to be sedated before they are investigated by transcranial magnetic stimulation because of the mild discomfort induced by the evoked muscle contraction and the noise of stimulation. This paper describes the influence of a combination of detomidine (10 microg/kg bodyweight) and a low dose of buprenorphine (2.4 microg/kg) on the onset latency and peak-to-peak amplitude of magnetic motor-evoked potentials in normal horses. There were no significant differences between measurements of these parameters made before the horses were sedated and measurements made 10 and 30 minutes after the drugs were administered.

Neurotoxic effects of n-hexane on the human central nervous system: evoked potential abnormalities in n-hexane polyneuropathy.

PubMed Central

Chang, Y C

1987-01-01

An outbreak of n-hexane polyneuropathy as a result of industrial exposure occurred in printing factories in Taipei area from December 1983 to February 1985. Multimodality evoked potentials study was performed on 22 of the polyneuropathy cases, five of the subclinical cases, and seven of the unaffected workers. The absolute and interpeak latencies of patterned visual evoked potential (pVEP) in both the polyneuropathy and subclinical groups were longer than in the normal controls. The pVEP interpeak amplitude was also decreased in the polyneuropathy cases. Brainstem auditory evoked potentials (BAEP), showed no difference of wave I latency between factory workers and normal controls, but prolongation of the wave I-V interpeak latencies was noted, corresponding with the severity of the polyneuropathy. In somatosensory evoked potentials (SEPs), both the absolute latencies and central conduction time (CCT) were longer in subclinical and polyneuropathy cases than in the unaffected workers and normal controls. From this evoked potentials study, chronic toxic effects of n-hexane on the central nervous system were shown. PMID:3031221

Human auditory evoked potentials. I - Evaluation of components

NASA Technical Reports Server (NTRS)

Picton, T. W.; Hillyard, S. A.; Krausz, H. I.; Galambos, R.

1974-01-01

Fifteen distinct components can be identified in the scalp recorded average evoked potential to an abrupt auditory stimulus. The early components occurring in the first 8 msec after a stimulus represent the activation of the cochlea and the auditory nuclei of the brainstem. The middle latency components occurring between 8 and 50 msec after the stimulus probably represent activation of both auditory thalamus and cortex but can be seriously contaminated by concurrent scalp muscle reflex potentials. The longer latency components occurring between 50 and 300 msec after the stimulus are maximally recorded over fronto-central scalp regions and seem to represent widespread activation of frontal cortex.

Generalized alternating stimulation: a novel method to reduce stimulus artifact in electrically evoked compound action potentials.

PubMed

Alvarez, Isaac; de la Torre, Angel; Sainz, Manuel; Roldan, Cristina; Schoesser, Hansjoerg; Spitzer, Philipp

2007-09-15

Stimulus artifact is one of the main limitations when considering electrically evoked compound action potential for clinical applications. Alternating stimulation (average of recordings obtained with anodic-cathodic and cathodic-anodic bipolar stimulation pulses) is an effective method to reduce stimulus artifact when evoked potentials are recorded. In this paper we extend the concept of alternating stimulation by combining anodic-cathodic and cathodic-anodic recordings with a weight in general different to 0.5. We also provide an automatic method to obtain an estimation of the optimal weights. Comparison with conventional alternating, triphasic stimulation and masker-probe paradigm shows that the generalized alternating method improves the quality of electrically evoked compound action potential responses.

Diagnostic accuracy of evoked potentials for functional impairment after contusive spinal cord injury in adult rats.

PubMed

Thirumala, Parthasarathy; Zhou, James; Krishnan, Rohan; Manem, Nihita; Umredkar, Shreya; Hamilton, D K; Balzer, Jeffrey R; Oudega, Martin

2016-03-01

Iatrogenic spinal cord injury (SCI) is a cause of potentially debilitating post-operative neurologic complications. Currently, intra-operative neurophysiological monitoring (IONM) via somatosensory evoked potentials and motor-evoked potentials is used to detect and prevent impending SCI. However, no empirically validated interventions exist to halt the progression of iatrogenic SCI once it is detected. This is in part due to the lack of a suitable translational model that mimics the circumstances surrounding iatrogenic SCI detected via IONM. Here, we evaluate a model of simulated contusive iatrogenic SCI detected via IONM in adult female Sprague-Dawley rats. We show that transient losses of somatosensory evoked potentials responses are 88.24% sensitive (95% confidence interval [CI] 63.53-98.20) and 80% specific (95% CI 51.91-95.43) for significant functional impairment following simulated iatrogenic SCI. Similarly, we show that transient losses in motor-evoked potentials responses are 70.83% sensitive (95% CI 48.91-87.33) and 100% specific (95% CI 62.91-100.00) for significant functional impairment following simulated iatrogenic SCI. These results indicate that our model is a suitable replica of the circumstances surrounding clinical iatrogenic SCI. Copyright © 2015 Elsevier Ltd. All rights reserved.

Whole-brain diffusion tensor imaging in correlation to visual-evoked potentials in multiple sclerosis: a tract-based spatial statistics analysis.

PubMed

Lobsien, D; Ettrich, B; Sotiriou, K; Classen, J; Then Bergh, F; Hoffmann, K-T

2014-01-01

Functional correlates of microstructural damage of the brain affected by MS are incompletely understood. The purpose of this study was to evaluate correlations of visual-evoked potentials with microstructural brain changes as determined by DTI in patients with demyelinating central nervous disease. Sixty-one patients with clinically isolated syndrome or MS were prospectively recruited. The mean P100 visual-evoked potential latencies of the right and left eyes of each patient were calculated and used for the analysis. For DTI acquisition, a single-shot echo-planar imaging pulse sequence with 80 diffusion directions was performed at 3T. Fractional anisotropy, radial diffusivity, and axial diffusivity were calculated and correlated with mean P100 visual-evoked potentials by tract-based spatial statistics. Significant negative correlations between mean P100 visual-evoked potentials and fractional anisotropy and significant positive correlations between mean P100 visual-evoked potentials and radial diffusivity were found widespread over the whole brain. The highest significance was found in the optic radiation, frontoparietal white matter, and corpus callosum. Significant positive correlations between mean P100 visual-evoked potentials and axial diffusivity were less widespread, notably sparing the optic radiation. Microstructural changes of the whole brain correlated significantly with mean P100 visual-evoked potentials. The distribution of the correlations showed clear differences among axial diffusivity, fractional anisotropy, and radial diffusivity, notably in the optic radiation. This finding suggests a stronger correlation of mean P100 visual-evoked potentials to demyelination than to axonal damage. © 2014 by American Journal of Neuroradiology.

Clinical use of vestibular evoked myogenic potentials in the evaluation of patients with air-bone gaps.

PubMed

Zhou, Guangwei; Poe, Dennis; Gopen, Quinton

2012-10-01

To determine the value of vestibular evoked myogenic potential (VEMP) test in clinical evaluation of air-bone gaps. Retrospective case review. Tertiary referral center. A total of 120 patients underwent VEMP testing during clinical investigation of significant air-bone gaps in their audiograms. Otologic examination and surgeries, high-resolution computerized tomography (CT), air and bone audiometry, tympanometry, acoustic reflex, and VEMP test. Imaging studies demonstrating structural anomalies in the temporal bone. Audiologic outcomes of air-bone gaps and VEMP thresholds. Surgical findings confirming imaging results. Middle ear pathologies, such as otosclerosis and chronic otitis media, were identified in 50 patients, and all of them had absent VEMP responses elicited by air-conduction stimuli. Moreover, 13 of them had successful middle ear surgeries with closures of the air-bone gaps. Abnormally low VEMP thresholds were found in 71 of 73 ears with inner ear anomalies, such as semicircular canal dehiscence and enlarged vestibular aqueduct. Seven patients with superior semicircular canal dehiscence underwent plugging procedure via middle fossa approach, and VEMP thresholds became normalized after the surgery in 3 of them. VEMP test failed to provide accurate diagnosis in only 3 cases. Air-bone gaps may be a result of various otologic pathologies, and the VEMP test is useful during clinical evaluation, better than tympanometry and acoustic reflexes. To avoid unnecessary middle ear surgery for air-bone gaps with unknown or unsure cause, VEMP test should be used in the differential diagnosis before an expensive imaging study.

Enhancement of electrically evoked oto-acoustic emissions associated with low-frequency stimulus bias of the basilar membrane towards scala vestibuli.

PubMed

Kirk, D L; Yates, G K

1998-09-01

Electrically evoked oto-acoustic emissions (EEOAEs) are sounds present in the ear canal when ac current is passed into the cochlea. EEOAEs are attributed to the activation of fast electromotile responses in outer hair cells (OHCs). An interesting property of EEOAEs is the phenomenon of "acoustic enhancement," where the emission amplitude is increased by moderate-level sound [D. C. Mountain and A. E. Hubbard, Hear. Res. 42, 195-202 (1989)]. In this report a form of enhancement is described which occurs with displacements of the basilar membrane toward scala vestibuli, during amplitude modulation of the EEOAE waveform by low-frequency tones. This "SV-bias enhancement" possibly consists of two components: (i) a low-level component induced by sound at levels which produce nonlinear growth of the cochlear microphonic and which may be equivalent to the "acoustic enhancement" described previously, and (ii) a high-level component which occurs at sound levels well above those which cause saturation of the cochlear microphonic. The low-level component could be explained by either an increased access of the extrinsically applied current to a membrane-based source of OHC motility, perhaps coupled with a reduction in negative feedback, or an increase in electromotile output during scala vestibuli displacements, but the origin of the high-level component is obscure.

Contact Heat Evoked Potentials (CHEPs) in Patients with Mild-Moderate Alzheimer's Disease and Matched Control--A Pilot Study.

PubMed

Jensen-Dahm, Christina; Madsen, Caspar Skau; Waldemar, Gunhild; Ballegaard, Martin; Hejl, Anne-Mette; Johnsen, Birger; Jensen, Troels Staehelin

2016-04-01

Clinical studies have found that patients with Alzheimer's disease report pain of less intensity and with a lower affective response, which has been thought to be due to altered pain processing. The authors wished to examine the cerebral processing of non-painful and painful stimuli using somatosensory evoked potentials and contact heat evoked potentials in patients with Alzheimer's disease and in healthy elderly controls. Case-control study Twenty outpatients with mild-moderate Alzheimer's disease and in 17 age- and gender-matched healthy controls were included Contact heat evoked potentials and somatosensory evoked potentials were recorded in all subjects. Furthermore, warmth detection threshold and heat pain threshold were assessed. Patients and controls also rated quality and intensity of the stimuli. The authors found no difference on contact heat evoked potential amplitude (P = 0.59) or latency of N2 or P2 wave (P = 0.62 and P = 0.75, respectively) between patients and controls. In addition, there was no difference in regard to pain intensity scores or pain quality. The patients and controls had similar warmth detection threshold and heat pain threshold. Somatosensory evoked potentials, amplitude, and latency were within normal range and similar for the two groups. The findings suggest that the processing of non-painful and painful stimuli is preserved in patients with mild to moderate Alzheimer's disease. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Middle Latency Auditory Evoked Potential (MLAEP) in Workers with and without Tinnitus who are Exposed to Occupational Noise.

PubMed

dos Santos Filha, Valdete Alves Valentins; Samelli, Alessandra Giannella; Matas, Carla Gentile

2015-09-11

Tinnitus is an important occupational health concern, but few studies have focused on the central auditory pathways of workers with a history of occupational noise exposure. Thus, we analyzed the central auditory pathways of workers with a history of occupational noise exposure who had normal hearing threshold, and compared middle latency auditory evoked potential in those with and without noise-induced tinnitus. Sixty individuals (30 with and 30 without tinnitus) underwent the following procedures: anamnesis, immittance measures, pure-tone air conduction thresholds at all frequencies between 0.25-8 kHz, and middle latency auditory evoked potentials. Quantitative analysis of latencies and amplitudes of middle latency auditory evoked potential showed no significant differences between the groups with and without tinnitus. In the qualitative analysis, we found that both groups showed increased middle latency auditory evoked potential latencies. The study group had more alterations of the "both" type regarding the Na-Pa amplitude, while the control group had more "electrode effect" alterations, but these alterations were not significantly different when compared to controls. Individuals with normal hearing with or without tinnitus who are exposed to occupational noise have altered middle latency auditory evoked potential, suggesting impairment of the auditory pathways in cortical and subcortical regions. Although differences did not reach significance, individuals with tinnitus seemed to have more abnormalities in components of the middle latency auditory evoked potential when compared to individuals without tinnitus, suggesting alterations in the generation and transmission of neuroelectrical impulses along the auditory pathway.

Brainstem auditory evoked potentials in children with lead exposure.

PubMed

Alvarenga, Katia de Freitas; Morata, Thais Catalani; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro; Corteletti, Lilian Cassia Bornia Jacob

2015-01-01

Earlier studies have demonstrated an auditory effect of lead exposure in children, but information on the effects of low chronic exposures needs to be further elucidated. To investigate the effect of low chronic exposures of the auditory system in children with a history of low blood lead levels, using an auditory electrophysiological test. Contemporary cross-sectional cohort. Study participants underwent tympanometry, pure tone and speech audiometry, transient evoked otoacoustic emissions, and brainstem auditory evoked potentials, with blood lead monitoring over a period of 35.5 months. The study included 130 children, with ages ranging from 18 months to 14 years, 5 months (mean age 6 years, 8 months ± 3 years, 2 months). The mean time-integrated cumulative blood lead index was 12 μg/dL (SD ± 5.7, range: 2.433). All participants had hearing thresholds equal to or below 20 dBHL and normal amplitudes of transient evoked otoacoustic emissions. No association was found between the absolute latencies of waves I, III, and V, the interpeak latencies I-III, III-V, and I-V, and the cumulative lead values. No evidence of toxic effects from chronic low lead exposures was observed on the auditory function of children living in a lead contaminated area. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Steady-State Somatosensory Evoked Potential for Brain-Computer Interface—Present and Future

PubMed Central

Ahn, Sangtae; Kim, Kiwoong; Jun, Sung Chan

2016-01-01

Brain-computer interface (BCI) performance has achieved continued improvement over recent decades, and sensorimotor rhythm-based BCIs that use motor function have been popular subjects of investigation. However, it remains problematic to introduce them to the public market because of their low reliability. As an alternative resolution to this issue, visual-based BCIs that use P300 or steady-state visually evoked potentials (SSVEPs) seem promising; however, the inherent visual fatigue that occurs with these BCIs may be unavoidable. For these reasons, steady-state somatosensory evoked potential (SSSEP) BCIs, which are based on tactile selective attention, have gained increasing attention recently. These may reduce the fatigue induced by visual attention and overcome the low reliability of motor activity. In this literature survey, recent findings on SSSEP and its methodological uses in BCI are reviewed. Further, existing limitations of SSSEP BCI and potential future directions for the technique are discussed. PMID:26834611

Feasibility and performance evaluation of generating and recording visual evoked potentials using ambulatory Bluetooth based system.

PubMed

Ellingson, Roger M; Oken, Barry

2010-01-01

Report contains the design overview and key performance measurements demonstrating the feasibility of generating and recording ambulatory visual stimulus evoked potentials using the previously reported custom Complementary and Alternative Medicine physiologic data collection and monitoring system, CAMAS. The methods used to generate visual stimuli on a PDA device and the design of an optical coupling device to convert the display to an electrical waveform which is recorded by the CAMAS base unit are presented. The optical sensor signal, synchronized to the visual stimulus emulates the brain's synchronized EEG signal input to CAMAS normally reviewed for the evoked potential response. Most importantly, the PDA also sends a marker message over the wireless Bluetooth connection to the CAMAS base unit synchronized to the visual stimulus which is the critical averaging reference component to obtain VEP results. Results show the variance in the latency of the wireless marker messaging link is consistent enough to support the generation and recording of visual evoked potentials. The averaged sensor waveforms at multiple CPU speeds are presented and demonstrate suitability of the Bluetooth interface for portable ambulatory visual evoked potential implementation on our CAMAS platform.

Long-Term Visuo-Gustatory Appetitive and Aversive Conditioning Potentiate Human Visual Evoked Potentials

PubMed Central

Christoffersen, Gert R. J.; Laugesen, Jakob L.; Møller, Per; Bredie, Wender L. P.; Schachtman, Todd R.; Liljendahl, Christina; Viemose, Ida

2017-01-01

Human recognition of foods and beverages are often based on visual cues associated with flavors. The dynamics of neurophysiological plasticity related to acquisition of such long-term associations has only recently become the target of investigation. In the present work, the effects of appetitive and aversive visuo-gustatory conditioning were studied with high density EEG-recordings focusing on late components in the visual evoked potentials (VEPs), specifically the N2-P3 waves. Unfamiliar images were paired with either a pleasant or an unpleasant juice and VEPs evoked by the images were compared before and 1 day after the pairings. In electrodes located over posterior visual cortex areas, the following changes were observed after conditioning: the amplitude from the N2-peak to the P3-peak increased and the N2 peak delay was reduced. The percentage increase of N2-to-P3 amplitudes was asymmetrically distributed over the posterior hemispheres despite the fact that the images were bilaterally symmetrical across the two visual hemifields. The percentage increases of N2-to-P3 amplitudes in each experimental subject correlated with the subject’s evaluation of positive or negative hedonic valences of the two juices. The results from 118 scalp electrodes gave surface maps of theta power distributions showing increased power over posterior visual areas after the pairings. Source current distributions calculated from swLORETA revealed that visual evoked currents rose as a result of conditioning in five cortical regions—from primary visual areas and into the inferior temporal gyrus (ITG). These learning-induced changes were seen after both appetitive and aversive training while a sham trained control group showed no changes. It is concluded that long-term visuo-gustatory conditioning potentiated the N2-P3 complex, and it is suggested that the changes are regulated by the perceived hedonic valence of the US. PMID:28983243

Interside Latency Differences in Brainstem Auditory and Somatosensory Evoked Potentials. Defining Upper Limits to Determine Asymmetry.

PubMed

Moncho, Dulce; Poca, Maria A; Minoves, Teresa; Ferré, Alejandro; Sahuquillo, Juan

2015-10-01

Limits of the interside differences are invaluable when interpreting asymmetry in brainstem auditory evoked potentials and somatosensory evoked potentials (SEP) recordings. The aim of this study was to analyze the normal upper limits of interside latency differences of brainstem auditory evoked potentials and SEP from the posterior tibial nerve and median nerve to determine asymmetry. The authors performed a prospective study in 56 healthy subjects aged 15 to 64 years with no neurological or hearing disorders. They analyzed (1) the latencies of I, III, and V waves and I-III, III-V, and I-V intervals and the amplitude ratios V/I and IV/I for brainstem auditory evoked potentials bilaterally; (2) the latencies of N8, N22, N28, and P37 waves and the interval N22-P37 and the amplitude P37 for posterior tibial nerve SEP bilaterally; and (3) the latencies and amplitudes of N9, N13, and N20 waves and N9-N13 and N13-N20 intervals for median nerve SEP bilaterally. The interside differences for these parameters were calculated and analyzed. The authors obtained an upper limit for the interside latency differences from brainstem auditory evoked potentials that was significantly lower than the previously published data. However, the upper limits of interside latency differences for SEP were similar to those previously reported. The findings of this study should be considered when laboratories analyze asymmetry using the normative data published by another center, however temporarily, in organizing new laboratories.

Thermoreceptive innervation of human glabrous and hairy skin: a contact heat evoked potential analysis.

PubMed

Granovsky, Yelena; Matre, Dagfinn; Sokolik, Alexander; Lorenz, Jürgen; Casey, Kenneth L

2005-06-01

The human palm has a lower heat detection threshold and a higher heat pain threshold than hairy skin. Neurophysiological studies of monkeys suggest that glabrous skin has fewer low threshold heat nociceptors (AMH type 2) than hairy skin. Accordingly, we used a temperature-controlled contact heat evoked potential (CHEP) stimulator to excite selectively heat receptors with C fibers or Adelta-innervated AMH type 2 receptors in humans. On the dorsal hand, 51 degrees C stimulation produced painful pinprick sensations and 41 degrees C stimuli evoked warmth. On the glabrous thenar, 41 degrees C stimulation produced mild warmth and 51 degrees C evoked strong but painless heat sensations. We used CHEP responses to estimate the conduction velocities (CV) of peripheral fibers mediating these sensations. On hairy skin, 41 degrees C stimuli evoked an ultra-late potential (mean, SD; N wave latency: 455 (118) ms) mediated by C fibers (CV by regression analysis: 1.28 m/s, N=15) whereas 51 degrees C stimuli evoked a late potential (N latency: 267 (33) ms) mediated by Adelta afferents (CV by within-subject analysis: 12.9 m/s, N=6). In contrast, thenar responses to 41 and 51 degrees C were mediated by C fibers (average N wave latencies 485 (100) and 433 (73) ms, respectively; CVs 0.95-1.35 m/s by regression analysis, N=15; average CV=1.7 (0.41) m/s calculated from distal glabrous and proximal hairy skin stimulation, N=6). The exploratory range of the human and monkey palm is enhanced by the abundance of low threshold, C-innervated heat receptors and the paucity of low threshold AMH type 2 heat nociceptors.

The association between later cortical potentials and later phases of postural reactions evoked by perturbations to upright stance.

PubMed

Quant, Sylvia; Maki, Brian E; McIlroy, William E

2005-06-24

Previous studies have suggested that early cortical potentials (e.g. N1) that are evoked by perturbations to upright stance are associated with sensory processing of the initial perturbation and that later potentials may represent cognitive processing of this perturbation. However, it has also been suggested that later cortical potentials could reflect sensory and motor processing of later phases of the postural reaction. The current study set out to provide additional insight into the association between perturbation-evoked cortical potentials and postural reactions evoked by whole-body perturbations. By altering the deceleration onset of the perturbation, which altered the timing of later postural responses, we determined whether changes in later postural responses were associated with changes in later potentials. Based on previous work, we hypothesized that later potentials would not be associated with changes in later postural responses. During stance, seven healthy young adults were instructed to maintain their balance following two types of perturbations: (1) acceleration phase immediately followed by a deceleration phase (TASK 1), and (2) acceleration phase followed by a delayed deceleration phase (TASK 2). In spite of profound task differences in later postural responses, results revealed no significant differences in later potentials. This work provides additional support for the idea that latter elements of perturbation-evoked cortical responses are likely independent of evoked motor reactions required to maintain stability.

Assessment of visual disability using visual evoked potentials.

PubMed

Jeon, Jihoon; Oh, Seiyul; Kyung, Sungeun

2012-08-06

The purpose of this study is to validate the use of visual evoked potential (VEP) to objectively quantify visual acuity in normal and amblyopic patients, and determine if it is possible to predict visual acuity in disability assessment to register visual pathway lesions. A retrospective chart review was conducted of patients diagnosed with normal vision, unilateral amblyopia, optic neuritis, and visual disability who visited the university medical center for registration from March 2007 to October 2009. The study included 20 normal subjects (20 right eyes: 10 females, 10 males, ages 9-42 years), 18 unilateral amblyopic patients (18 amblyopic eyes, ages 19-36 years), 19 optic neuritis patients (19 eyes: ages 9-71 years), and 10 patients with visual disability having visual pathway lesions. Amplitude and latencies were analyzed and correlations with visual acuity (logMAR) were derived from 20 normal and 18 amblyopic subjects. Correlation of VEP amplitude and visual acuity (logMAR) of 19 optic neuritis patients confirmed relationships between visual acuity and amplitude. We calculated the objective visual acuity (logMAR) of 16 eyes from 10 patients to diagnose the presence or absence of visual disability using relations derived from 20 normal and 18 amblyopic eyes. Linear regression analyses between amplitude of pattern visual evoked potentials and visual acuity (logMAR) of 38 eyes from normal (right eyes) and amblyopic (amblyopic eyes) subjects were significant [y = -0.072x + 1.22, x: VEP amplitude, y: visual acuity (logMAR)]. There were no significant differences between visual acuity prediction values, which substituted amplitude values of 19 eyes with optic neuritis into function. We calculated the objective visual acuity of 16 eyes of 10 patients to diagnose the presence or absence of visual disability using relations of y = -0.072x + 1.22 (-0.072). This resulted in a prediction reference of visual acuity associated with malingering vs. real

Assessment of visual disability using visual evoked potentials

PubMed Central

2012-01-01

Background The purpose of this study is to validate the use of visual evoked potential (VEP) to objectively quantify visual acuity in normal and amblyopic patients, and determine if it is possible to predict visual acuity in disability assessment to register visual pathway lesions. Methods A retrospective chart review was conducted of patients diagnosed with normal vision, unilateral amblyopia, optic neuritis, and visual disability who visited the university medical center for registration from March 2007 to October 2009. The study included 20 normal subjects (20 right eyes: 10 females, 10 males, ages 9–42 years), 18 unilateral amblyopic patients (18 amblyopic eyes, ages 19–36 years), 19 optic neuritis patients (19 eyes: ages 9–71 years), and 10 patients with visual disability having visual pathway lesions. Amplitude and latencies were analyzed and correlations with visual acuity (logMAR) were derived from 20 normal and 18 amblyopic subjects. Correlation of VEP amplitude and visual acuity (logMAR) of 19 optic neuritis patients confirmed relationships between visual acuity and amplitude. We calculated the objective visual acuity (logMAR) of 16 eyes from 10 patients to diagnose the presence or absence of visual disability using relations derived from 20 normal and 18 amblyopic eyes. Results Linear regression analyses between amplitude of pattern visual evoked potentials and visual acuity (logMAR) of 38 eyes from normal (right eyes) and amblyopic (amblyopic eyes) subjects were significant [y = −0.072x + 1.22, x: VEP amplitude, y: visual acuity (logMAR)]. There were no significant differences between visual acuity prediction values, which substituted amplitude values of 19 eyes with optic neuritis into function. We calculated the objective visual acuity of 16 eyes of 10 patients to diagnose the presence or absence of visual disability using relations of y = −0.072x + 1.22 (−0.072). This resulted in a prediction reference of visual

Direct detection of a single evoked action potential with MRS in Lumbricus terrestris.

PubMed

Poplawsky, Alexander J; Dingledine, Raymond; Hu, Xiaoping P

2012-01-01

Functional MRI (fMRI) measures neural activity indirectly by detecting the signal change associated with the hemodynamic response following brain activation. In order to alleviate the temporal and spatial specificity problems associated with fMRI, a number of attempts have been made to detect neural magnetic fields (NMFs) with MRI directly, but have thus far provided conflicting results. In this study, we used MR to detect axonal NMFs in the median giant fiber of the earthworm, Lumbricus terrestris, by examining the free induction decay (FID) with a sampling interval of 0.32 ms. The earthworm nerve cords were isolated from the vasculature and stimulated at the threshold of action potential generation. FIDs were acquired shortly after the stimulation, and simultaneous field potential recordings identified the presence or absence of single evoked action potentials. FIDs acquired when the stimulus did not evoke an action potential were summed as background. The phase of the background-subtracted FID exhibited a systematic change, with a peak phase difference of (-1.2 ± 0.3) × 10(-5) radians occurring at a time corresponding to the timing of the action potential. In addition, we calculated the possible changes in the FID magnitude and phase caused by a simulated action potential using a volume conductor model. The measured phase difference matched the theoretical prediction well in both amplitude and temporal characteristics. This study provides the first evidence for the direct detection of a magnetic field from an evoked action potential using MR. Copyright © 2011 John Wiley & Sons, Ltd.

Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

PubMed

Kawaguchi, Jun; Matsuura, Nobuyuki; Kasahara, Masataka; Ichinohe, Tatsuya

2015-02-01

The purpose of this study was to investigate the latency and amplitude of trigeminal somatosensory evoked potentials to clarify how nerve function on the contralateral side is affected after cervical sympathetic block (CSB). Subjects comprised 16 volunteers. For CSB, the tip of a needle was contacted with the transverse process of the sixth cervical vertebra on the right side, and lidocaine was injected. Trigeminal somatosensory evoked potentials were recorded bilaterally from C5/C6 scalp positions. Pupil diameters were also measured. Electrical stimulations were applied to the left-side lower lip, and trigeminal somatosensory evoked potentials waveforms derived from both sides of the scalp were recorded. Then, electrical stimulations were applied to the right-side of the lower lip, and recording was again performed. Recordings were performed at 5, 15, and 30 minutes after CSB. On the CSB side, pupil diameter decreased at 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials at contralateral stimulation showed a prolongation of the latency in both P20 and N25 components on bilateral recording sites 5 and 15 minutes after CSB. Trigeminal somatosensory evoked potentials' amplitude at contralateral stimulation was smaller than at ipsilateral stimulation 5 minutes after CSB. Cervical sympathetic block prolongs the latency and reduces the amplitude of trigeminal somatosensory evoked potentials on the contralateral side.

Disturbances of stem circumnutations evoked by wound-induced variation potentials in Helianthus annuus L.

PubMed

Stolarz, Maria; Dziubińska, Halina; Krupa, Maciej; Buda, Agnieszka; Trebacz, Kazimierz; Zawadzki, Tadeusz

2003-01-01

The relationship between evoked electrical activity and stem movements in three-week old sunflowers was demonstrated. Electrical potential changes (recorded by Ag/AgCl extracellular electrodes) and time-lapse images (from a top view camera) were recorded and analyzed. A heat stimulus applied to the tip of one of the second pair of leaves evoked a variation potential, transmitted basipetally along one side of the stem. After stimulation, disturbances of circumnutations occurred. They included: changes in the period, disorders in the elliptical shape, and, in some cases, reversion of direction (of movement). We suggest that asymmetrically propagated variation potential induces asymmetric stem shrinking and bending, which strongly disturbs circumnutations. Our results confirm the involvement of electrical potential changes in the mechanism of stem nutations.

Optimization of visual evoked potential (VEP) recording systems.

PubMed

Karanjia, Rustum; Brunet, Donald G; ten Hove, Martin W

2009-01-01

To explore the influence of environmental conditions on pattern visual evoked potential (VEP) recordings. Fourteen subjects with no known ocular pathology were recruited for the study. In an attempt to optimize the recording conditions, VEP recordings were performed in both the seated and recumbent positions. Comparisons were made between recordings using either LCD or CRT displays and recordings obtained in silence or with quiet background music. Paired recordings (in which only one variable was changed) were analyzed for changes in P100 latency, RMS noise, and variability. Baseline RMS noise demonstrated a significant decrease in the variability during the first 50msec accompanied by a 73% decrease in recording time for recumbent position when compared to the seated position (p<0.05). Visual evoked potentials recorded using LCD monitors demonstrated a significant increase in the P100 latency when compared to CRT recordings in the same subjects. The addition of background music did not affect the amount of RMS noise during the first 50msec of the recordings. This study demonstrates that the use of the recumbent position increases patient comfort and improves the signal to noise ratio. In contrast, the addition of background music to relax the patient did not improve the recording signal. Furthermore, the study illustrates the importance of avoiding low-contrast visual stimulation patterns obtained with LCD as they lead to higher latencies resulting in false positive recordings. These findings are important when establishing or modifying a pattern VEP recording protocol.

Evoked-potential changes following discrimination learning involving complex sounds

PubMed Central

Orduña, Itzel; Liu, Estella H.; Church, Barbara A.; Eddins, Ann C.; Mercado, Eduardo

2011-01-01

Objective Perceptual sensitivities are malleable via learning, even in adults. We trained adults to discriminate complex sounds (periodic, frequency-modulated sweep trains) using two different training procedures, and used psychoacoustic tests and evoked potential measures (the N1-P2 complex) to assess changes in both perceptual and neural sensitivities. Methods Training took place either on a single day, or daily across eight days, and involved discrimination of pairs of stimuli using a single-interval, forced-choice task. In some participants, training started with dissimilar pairs that became progressively more similar across sessions, whereas in others training was constant, involving only one, highly similar, stimulus pair. Results Participants were better able to discriminate the complex sounds after training, particularly after progressive training, and the evoked potentials elicited by some of the sounds increased in amplitude following training. Significant amplitude changes were restricted to the P2 peak. Conclusion Our findings indicate that changes in perceptual sensitivities parallel enhanced neural processing. Significance These results are consistent with the proposal that changes in perceptual abilities arise from the brain’s capacity to adaptively modify cortical representations of sensory stimuli, and that different training regimens can lead to differences in cortical sensitivities, even after relatively short periods of training. PMID:21958655

Effect of mechanical tactile noise on amplitude of visual evoked potentials: multisensory stochastic resonance.

PubMed

Méndez-Balbuena, Ignacio; Huidobro, Nayeli; Silva, Mayte; Flores, Amira; Trenado, Carlos; Quintanar, Luis; Arias-Carrión, Oscar; Kristeva, Rumyana; Manjarrez, Elias

2015-10-01

The present investigation documents the electrophysiological occurrence of multisensory stochastic resonance in the human visual pathway elicited by tactile noise. We define multisensory stochastic resonance of brain evoked potentials as the phenomenon in which an intermediate level of input noise of one sensory modality enhances the brain evoked response of another sensory modality. Here we examined this phenomenon in visual evoked potentials (VEPs) modulated by the addition of tactile noise. Specifically, we examined whether a particular level of mechanical Gaussian noise applied to the index finger can improve the amplitude of the VEP. We compared the amplitude of the positive P100 VEP component between zero noise (ZN), optimal noise (ON), and high mechanical noise (HN). The data disclosed an inverted U-like graph for all the subjects, thus demonstrating the occurrence of a multisensory stochastic resonance in the P100 VEP. Copyright © 2015 the American Physiological Society.

Use of the Stockwell Transform in the Detection of P300 Evoked Potentials with Low-Cost Brain Sensors.

PubMed

Pérez-Vidal, Alan F; Garcia-Beltran, Carlos D; Martínez-Sibaja, Albino; Posada-Gómez, Rubén

2018-05-09

The evoked potential is a neuronal activity that originates when a stimulus is presented. To achieve its detection, various techniques of brain signal processing can be used. One of the most studied evoked potentials is the P300 brain wave, which usually appears between 300 and 500 ms after the stimulus. Currently, the detection of P300 evoked potentials is of great importance due to its unique properties that allow the development of applications such as spellers, lie detectors, and diagnosis of psychiatric disorders. The present study was developed to demonstrate the usefulness of the Stockwell transform in the process of identifying P300 evoked potentials using a low-cost electroencephalography (EEG) device with only two brain sensors. The acquisition of signals was carried out using the Emotiv EPOC ® device—a wireless EEG headset. In the feature extraction, the Stockwell transform was used to obtain time-frequency information. The algorithms of linear discriminant analysis and a support vector machine were used in the classification process. The experiments were carried out with 10 participants; men with an average age of 25.3 years in good health. In general, a good performance (75⁻92%) was obtained in identifying P300 evoked potentials.

Intelligence and Complexity of the Averaged Evoked Potential: An Attentional Theory.

ERIC Educational Resources Information Center

Bates, Tim; And Others

1995-01-01

A study measuring average evoked potentials in 21 college students finds that intelligence test scores correlate significantly with the difference between string length in attended and nonattended conditions, a finding that suggests that previous inconsistencies in reporting string length-intelligence correlations may have resulted from confound…

The Nature and Process of Development in Averaged Visually Evoked Potentials: Discussion on Pattern Structure.

ERIC Educational Resources Information Center

Izawa, Shuji; Mizutani, Tohru

This paper examines the development of visually evoked EEG patterns in retarded and normal subjects. The paper focuses on the averaged visually evoked potentials (AVEP) in the central and occipital regions of the brain in eyes closed and eyes open conditions. Wave pattern, amplitude, and latency are examined. The first section of the paper reviews…

Changes in visual-evoked potential habituation induced by hyperventilation in migraine.

PubMed

Coppola, Gianluca; Currà, Antonio; Sava, Simona Liliana; Alibardi, Alessia; Parisi, Vincenzo; Pierelli, Francesco; Schoenen, Jean

2010-12-01

Hyperventilation is often associated with stress, an established trigger factor for migraine. Between attacks, migraine is associated with a deficit in habituation to visual-evoked potentials (VEP) that worsens just before the attack. Hyperventilation slows electroencephalographic (EEG) activity and decreases the functional response in the occipital cortex during visual stimulation. The neural mechanisms underlying deficient-evoked potential habituation in migraineurs remain unclear. To find out whether hyperventilation alters VEP habituation, we recorded VEPs before and after experimentally induced hyperventilation lasting 3 min in 18 healthy subjects and 18 migraine patients between attacks. We measured VEP P100 amplitudes in six sequential blocks of 100 sweeps and habituation as the change in amplitude over the six blocks. In healthy subjects, hyperventilation decreased VEP amplitude in block 1 and abolished the normal VEP habituation. In migraine patients, hyperventilation further decreased the already low block 1 amplitude and worsened the interictal habituation deficit. Hyperventilation worsens the habituation deficit in migraineurs possibly by increasing dysrhythmia in the brainstem-thalamo-cortical network.

On wavelet analysis of auditory evoked potentials.

PubMed

Bradley, A P; Wilson, W J

2004-05-01

To determine a preferred wavelet transform (WT) procedure for multi-resolution analysis (MRA) of auditory evoked potentials (AEP). A number of WT algorithms, mother wavelets, and pre-processing techniques were examined by way of critical theoretical discussion followed by experimental testing of key points using real and simulated auditory brain-stem response (ABR) waveforms. Conclusions from these examinations were then tested on a normative ABR dataset. The results of the various experiments are reported in detail. Optimal AEP WT MRA is most likely to occur when an over-sampled discrete wavelet transformation (DWT) is used, utilising a smooth (regularity >or=3) and symmetrical (linear phase) mother wavelet, and a reflection boundary extension policy. This study demonstrates the practical importance of, and explains how to minimize potential artefacts due to, 4 inter-related issues relevant to AEP WT MRA, namely shift variance, phase distortion, reconstruction smoothness, and boundary artefacts.

Utility of Brainstem Trigeminal Evoked Potentials in Patients With Primary Trigeminal Neuralgia Treated by Microvascular Decompression.

PubMed

Zhu, Jin; Zhang, Xin; Zhao, Hua; Tang, Yin-Da; Ying, Ting-Ting; Li, Shi-Ting

2017-09-01

To investigate the characteristics of brainstem trigeminal evoked potentials (BTEP) waveform in patients with and without trigeminal neuralgia (TN), and to discuss the utility of BTEP in patients with primary TN treated by microvascular decompression (MVD). A retrospective review of 43 patients who underwent BTEP between January 2016 and June 2016, including 33 patients with TN who underwent MVD and 10 patients without TN. Brainstem trigeminal evoked potentials characteristics of TN and non-TN were summarized, in particular to compare the BTEP changes between pre- and post-MVD, and to discover the relationship between BTEP changes and surgical outcome. Brainstem trigeminal evoked potentials can be recorded in patients without trigeminal neuralgia. Abnormal BTEP could be recorded when different branches were stimulated. After decompression, the original W2, W3 disappeared and then replaced by a large wave in most patients, or original wave poorly differentiated improved in some patients, showed as shorter latency and (or) amplitude increased. Brainstem trigeminal evoked potentials waveform of healthy side in patients with trigeminal neuralgia was similar to the waveform of patients without TN. In 3 patients, after decompression the W2, W3 peaks increased, and the latency, duration, IPLD did not change significantly. Until discharge, 87.9% (29/33) of the patients presented complete absence of pain without medication (BNI I) and 93.9% (31/33) had good pain control without medication (BNI I-II). Brainstem trigeminal evoked potentials can reflect the conduction function of the trigeminal nerve to evaluate the functional level of the trigeminal nerve conduction pathway. The improvement and restoration of BTEP waveforms are closely related to the postoperative curative effect.

A Steady State Visually Evoked Potential Investigation of Memory and Ageing

ERIC Educational Resources Information Center

Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

2009-01-01

Old age is generally accompanied by a decline in memory performance. Specifically, neuroimaging and electrophysiological studies have revealed that there are age-related changes in the neural correlates of episodic and working memory. This study investigated age-associated changes in the steady state visually evoked potential (SSVEP) amplitude and…

Acoustic analysis of warp potential of green ponderosa pine lumber

Treesearch

Xiping Wang; William T. Simpson

2005-01-01

This study evaluated the potential of acoustic analysis as presorting criteria to identify warp-prone boards before kiln drying. Dimension lumber, 38 by 89 mm (nominal 2 by 4 in.) and 2.44 m (8 ft) long, sawn from open-grown small-diameter ponderosa pine trees, was acoustically tested lengthwise at green condition. Three acoustic properties (acoustic speed, rate of...

A new role for evoked potentials in MS? Repurposing evoked potentials as biomarkers for clinical trials in MS.

PubMed

Hardmeier, Martin; Leocani, Letizia; Fuhr, Peter

2017-09-01

Evoked potentials (EP) characterize signal conduction in selected tracts of the central nervous system in a quantifiable way. Since alteration of signal conduction is the main mechanism of symptoms and signs in multiple sclerosis (MS), multimodal EP may serve as a representative measure of the functional impairment in MS. Moreover, EP have been shown to be predictive for disease course, and thus might help to select patient groups at high risk of progression for clinical trials. EP can detect deterioration, as well as improvement of impulse propagation, independently from the mechanism causing the change. Therefore, they are candidates for biomarkers with application in clinical phase-II trials. Applicability of EP in multicenter trials has been limited by different standards of registration and assessment.

Hearing in the Juvenile Green Sea Turtle (Chelonia mydas): A Comparison of Underwater and Aerial Hearing Using Auditory Evoked Potentials

PubMed Central

Piniak, Wendy E. D.; Mann, David A.; Harms, Craig A.; Jones, T. Todd; Eckert, Scott A.

2016-01-01

Sea turtles spend much of their life in aquatic environments, but critical portions of their life cycle, such as nesting and hatching, occur in terrestrial environments, suggesting that it may be important for them to detect sounds in both air and water. In this study we compared underwater and aerial hearing sensitivities in five juvenile green sea turtles (Chelonia mydas) by measuring auditory evoked potential responses to tone pip stimuli. Green sea turtles detected acoustic stimuli in both media, responding to underwater stimuli between 50 and 1600 Hz and aerial stimuli between 50 and 800 Hz, with maximum sensitivity between 200 and 400 Hz underwater and 300 and 400 Hz in air. When underwater and aerial hearing sensitivities were compared in terms of pressure, green sea turtle aerial sound pressure thresholds were lower than underwater thresholds, however they detected a wider range of frequencies underwater. When thresholds were compared in terms of sound intensity, green sea turtle sound intensity level thresholds were 2–39 dB lower underwater particularly at frequencies below 400 Hz. Acoustic stimuli may provide important environmental cues for sea turtles. Further research is needed to determine how sea turtles behaviorally and physiologically respond to sounds in their environment. PMID:27741231

Hearing in the Juvenile Green Sea Turtle (Chelonia mydas): A Comparison of Underwater and Aerial Hearing Using Auditory Evoked Potentials.

PubMed

Piniak, Wendy E D; Mann, David A; Harms, Craig A; Jones, T Todd; Eckert, Scott A

2016-01-01

Sea turtles spend much of their life in aquatic environments, but critical portions of their life cycle, such as nesting and hatching, occur in terrestrial environments, suggesting that it may be important for them to detect sounds in both air and water. In this study we compared underwater and aerial hearing sensitivities in five juvenile green sea turtles (Chelonia mydas) by measuring auditory evoked potential responses to tone pip stimuli. Green sea turtles detected acoustic stimuli in both media, responding to underwater stimuli between 50 and 1600 Hz and aerial stimuli between 50 and 800 Hz, with maximum sensitivity between 200 and 400 Hz underwater and 300 and 400 Hz in air. When underwater and aerial hearing sensitivities were compared in terms of pressure, green sea turtle aerial sound pressure thresholds were lower than underwater thresholds, however they detected a wider range of frequencies underwater. When thresholds were compared in terms of sound intensity, green sea turtle sound intensity level thresholds were 2-39 dB lower underwater particularly at frequencies below 400 Hz. Acoustic stimuli may provide important environmental cues for sea turtles. Further research is needed to determine how sea turtles behaviorally and physiologically respond to sounds in their environment.

Evoked potential correlates of figure and ground.

PubMed

Landis, T; Lehmann, D; Mita, T; Skrandies, W

1984-06-01

Brain potentials averaged during the viewing of an alternating, positive and negative "hidden man" puzzle picture were averaged from 8 subjects before and after they learned to recognize the figure. After figure recognition in comparison to before recognition, there was significantly more evoked positivity at 64/96 ms latency, and more negativity at 224/256 ms and at 352-480 ms latency over parietal areas during the viewing of the positive picture (recognizable as face) referred to the values obtained during viewing of the negative picture (not recognizable as face). It is hypothesized that separate physiological changes might reflect learned meaningfulness of the figure (which entails increased attention) and figure extraction from ground.

Brain state-dependence of electrically evoked potentials monitored with head-mounted electronics.

PubMed

Richardson, Andrew G; Fetz, Eberhard E

2012-11-01

Inferring changes in brain connectivity is critical to studies of learning-related plasticity and stimulus-induced conditioning of neural circuits. In addition, monitoring spontaneous fluctuations in connectivity can provide insight into information processing during different brain states. Here, we quantified state-dependent connectivity changes throughout the 24-h sleep-wake cycle in freely behaving monkeys. A novel, head-mounted electronic device was used to electrically stimulate at one site and record evoked potentials at other sites. Electrically evoked potentials (EEPs) revealed the connectivity pattern between several cortical sites and the basal forebrain. We quantified state-dependent changes in the EEPs. Cortico-cortical EEP amplitude increased during slow-wave sleep, compared to wakefulness, while basal-cortical EEP amplitude decreased. The results demonstrate the utility of using portable electronics to document state-dependent connectivity changes in freely behaving primates.

Brainstem auditory evoked potential wave V latency-intensity function in normal Dalmatian and Beagle puppies.

PubMed

Poncelet, L; Coppens, A; Deltenre, P

2000-01-01

This study investigated whether Dalmatian puppies with normal hearing bilaterally had the same click-evoked brainstem auditory potential characteristics as age-matched dogs of another breed. Short-latency brainstem auditory potentials evoked by condensation and rarefaction clicks were recorded in 23 1.5- to 2-month-old Dalmatian puppies with normal hearing bilaterally by a qualitative brainstem auditory evoked potential test and in 16 Beagle dogs of the same age. For each stimulus intensity, from 90 dB normal hearing level down to the wave V threshold, the sum of the potentials evoked by the 2 kinds of stimuli were added, giving an equivalent to the alternate click polarity stimulation. The slope of the L segment of the wave V latency-intensity curve was steeper in Dalmatian (-40 +/- 10 micros/dB) than in Beagles (-28 +/- 5 micros/dB, P < .001) puppies. The hearing threshold was lower in the Beagle puppies (P < .05). These results suggest that interbreed differences may exist at the level of cochlear function in this age class. The wave V latency and wave V-wave I latencies differences at high stimulus intensity were different between the groups of puppies (4.3 +/- 0.2 and 2.5 +/- 0.2 milliseconds, respectively, for Beagles; and 4.1 +/- 0.2 and 2.3 +/- 0.2 milliseconds for Dalmatians, P < .05). A different maturation speed of the neural pathways is one possible explanation of this observation.

Effects of Long-Term Musical Training on Cortical Auditory Evoked Potentials.

PubMed

Brown, Carolyn J; Jeon, Eun-Kyung; Driscoll, Virginia; Mussoi, Bruna; Deshpande, Shruti Balvalli; Gfeller, Kate; Abbas, Paul J

Evidence suggests that musicians, as a group, have superior frequency resolution abilities when compared with nonmusicians. It is possible to assess auditory discrimination using either behavioral or electrophysiologic methods. The purpose of this study was to determine if the acoustic change complex (ACC) is sensitive enough to reflect the differences in spectral processing exhibited by musicians and nonmusicians. Twenty individuals (10 musicians and 10 nonmusicians) participated in this study. Pitch and spectral ripple discrimination were assessed using both behavioral and electrophysiologic methods. Behavioral measures were obtained using a standard three interval, forced choice procedure. The ACC was recorded and used as an objective (i.e., nonbehavioral) measure of discrimination between two auditory signals. The same stimuli were used for both psychophysical and electrophysiologic testing. As a group, musicians were able to detect smaller changes in pitch than nonmusician. They also were able to detect a shift in the position of the peaks and valleys in a ripple noise stimulus at higher ripple densities than non-musicians. ACC responses recorded from musicians were larger than those recorded from non-musicians when the amplitude of the ACC response was normalized to the amplitude of the onset response in each stimulus pair. Visual detection thresholds derived from the evoked potential data were better for musicians than non-musicians regardless of whether the task was discrimination of musical pitch or detection of a change in the frequency spectrum of the ripple noise stimuli. Behavioral measures of discrimination were generally more sensitive than the electrophysiologic measures; however, the two metrics were correlated. Perhaps as a result of extensive training, musicians are better able to discriminate spectrally complex acoustic signals than nonmusicians. Those differences are evident not only in perceptual/behavioral tests but also in electrophysiologic

Effect of combined opioid receptor and α2-adrenoceptor blockade on anxiety and electrically evoked startle responses.

PubMed

Vo, Lechi; Drummond, Peter D

2017-06-01

The R3 component of the electrically evoked blink reflex may form part of a startle reaction. Acoustic startle responses are augmented by yohimbine, an α 2 -adrenoceptor antagonist that blocks α 2 -autoreceptors, and are potentiated by opioid receptor blockade. To investigate these influences on electrically evoked startle responses, 16 mg yohimbine, with (16 participants) or without 50 mg naltrexone (23 participants), was administered in separate double-blind placebo-controlled cross-over experiments. In each experiment, R3 (a probable component of the startle response) was examined before and after high-frequency electrical stimulation of the forearm, a procedure that initiates inhibitory pain controls. Anxiety and somatic symptoms were greater after yohimbine than placebo, and were potentiated by naltrexone. Pain ratings for the electrically evoked startle stimuli decreased after high-frequency electrical stimulation in the placebo session but remained stable after drug administration. Yohimbine with naltrexone, but not yohimbine alone, also blocked an inhibitory effect of high-frequency electrical stimulation on electrically evoked sharp sensations and R3. Together, the findings suggest that adding naltrexone to yohimbine potentiated anxiety and blocked inhibitory influences of high-frequency electrical stimulation on electrically evoked sensations and startle responses. Thus, opioid peptides could reduce activity in nociceptive and startle-reflex pathways, or inhibit crosstalk between these pathways. Failure of this inhibitory opioid influence might be important in chronically painful conditions that are aggravated by startle stimuli.

Intraoperative Monitoring: Recent Advances in Motor Evoked Potentials.

PubMed

Koht, Antoun; Sloan, Tod B

2016-09-01

Advances in electrophysiological monitoring have improved the ability of surgeons to make decisions and minimize the risks of complications during surgery and interventional procedures when the central nervous system (CNS) is at risk. Individual techniques have become important for identifying or mapping the location and pathway of critical neural structures. These techniques are also used to monitor the progress of procedures to augment surgical and physiologic management so as to reduce the risk of CNS injury. Advances in motor evoked potentials have facilitated mapping and monitoring of the motor tracts in newer, more complex procedures. Copyright © 2016 Elsevier Inc. All rights reserved.

Steady-state pattern electroretinogram and short-duration transient visual evoked potentials in glaucomatous and healthy eyes.

PubMed

Amarasekera, Dilru C; Resende, Arthur F; Waisbourd, Michael; Puri, Sanjeev; Moster, Marlene R; Hark, Lisa A; Katz, L Jay; Fudemberg, Scott J; Mantravadi, Anand V

2018-01-01

This study evaluates two rapid electrophysiological glaucoma diagnostic tests that may add a functional perspective to glaucoma diagnosis. This study aimed to determine the ability of two office-based electrophysiological diagnostic tests, steady-state pattern electroretinogram and short-duration transient visual evoked potentials, to discern between glaucomatous and healthy eyes. This is a cross-sectional study in a hospital setting. Forty-one patients with glaucoma and 41 healthy volunteers participated in the study. Steady-state pattern electroretinogram and short-duration transient visual evoked potential testing was conducted in glaucomatous and healthy eyes. A 64-bar-size stimulus with both a low-contrast and high-contrast setting was used to compare steady-state pattern electroretinogram parameters in both groups. A low-contrast and high-contrast checkerboard stimulus was used to measure short-duration transient visual evoked potential parameters in both groups. Steady-state pattern electroretinogram parameters compared were MagnitudeD, MagnitudeD/Magnitude ratio, and the signal-to-noise ratio. Short-duration transient visual evoked potential parameters compared were amplitude and latency. MagnitudeD was significantly lower in glaucoma patients when using a low-contrast (P = 0.001) and high-contrast (P < 0.001) 64-bar-size steady-state pattern electroretinogram stimulus. MagnitudeD/Magnitude ratio and SNR were significantly lower in the glaucoma group when using a high-contrast 64-bar-size stimulus (P < 0.001 and P = 0.010, respectively). Short-duration transient visual evoked potential amplitude and latency were not significantly different between the two groups. Steady-state pattern electroretinogram was effectively able to discern between glaucomatous and healthy eyes. Steady-state pattern electroretinogram may thus have a role as a clinically useful electrophysiological diagnostic tool. © 2017 Royal Australian and New Zealand College of

Use of auditory evoked potentials for intra-operative awareness in anesthesia: a consciousness-based conceptual model.

PubMed

Dong, Xuebao; Suo, Puxia; Yuan, Xin; Yao, Xuefeng

2015-01-01

Auditory evoked potentials (AEPs) have been used as a measure of the depth of anesthesia during the intra-operative process. AEPs are classically divided, on the basis of their latency, into first, fast, middle, slow, and late components. The use of auditory evoked potential has been advocated for the assessment of Intra-operative awareness (IOA), but has not been considered seriously enough to universalize it. It is because we have not explored enough the impact of auditory perception and auditory processing on the IOA phenomena as well as on the subsequent psychological impact of IOA on the patient. More importantly, we have seldom tried to look at the phenomena of IOP from the perspective of consciousness itself. This perspective is especially important because many of IOA phenomena exist in the subconscious domain than they do in the conscious domain of explicit recall. Two important forms of these subconscious manifestations of IOA are the implicit recall phenomena and post-operative dreams related to the operation. Here, we present an integrated auditory consciousness-based model of IOA. We start with a brief description of auditory awareness and the factors affecting it. Further, we proceed to the evaluation of conscious and subconscious information processing by auditory modality and how they interact during and after intra-operative period. Further, we show that both conscious and subconscious auditory processing affect the IOA experience and both have serious psychological implications on the patient subsequently. These effects could be prevented by using auditory evoked potential during monitoring of anesthesia, especially the mid-latency auditory evoked potentials (MLAERs). To conclude our model with present hypothesis, we propose that the use of auditory evoked potential should be universal with general anesthesia use in order to prevent the occurrences of distressing outcomes resulting from both conscious and subconscious auditory processing during

Low-frequency rTMS inhibitory effects in the primary motor cortex: Insights from TMS-evoked potentials.

PubMed

Casula, Elias P; Tarantino, Vincenza; Basso, Demis; Arcara, Giorgio; Marino, Giuliana; Toffolo, Gianna Maria; Rothwell, John C; Bisiacchi, Patrizia S

2014-09-01

The neuromodulatory effects of repetitive transcranial magnetic stimulation (rTMS) have been mostly investigated by peripheral motor-evoked potentials (MEPs). New TMS-compatible EEG systems allow a direct investigation of the stimulation effects through the analysis of TMS-evoked potentials (TEPs). We investigated the effects of 1-Hz rTMS over the primary motor cortex (M1) of 15 healthy volunteers on TEP evoked by single pulse TMS over the same area. A second experiment in which rTMS was delivered over the primary visual cortex (V1) of 15 healthy volunteers was conducted to examine the spatial specificity of the effects. Single-pulse TMS evoked four main components: P30, N45, P60 and N100. M1-rTMS resulted in a significant decrease of MEP amplitude and in a significant increase of P60 and N100 amplitude. There was no effect after V1-rTMS. 1-Hz rTMS appears to increase the amount of inhibition following a TMS pulse, as demonstrated by the higher N100 and P60, which are thought to originate from GABAb-mediated inhibitory post-synaptic potentials. Our results confirm the reliability of the TMS-evoked N100 as a marker of cortical inhibition and provide insight into the neuromodulatory effects of 1-Hz rTMS. The present finding could be of relevance for therapeutic and diagnostic purposes. Copyright © 2014 Elsevier Inc. All rights reserved.

The ventricular intracardiac unipolar paced-evoked potential in an isolated animal heart.

PubMed

Economides, A P; Walton, C; Gergely, S

1988-02-01

The endocardial unipolar paced evoked response has excited a great deal of interest due to its possible use in the measurement of the metabolic state of the body and other pacer-related areas. Although rate-responsive pacing utilizing this signal has been clinically evaluated, little is known regarding the behavior of the components of this waveform under normal physiological conditions. We have developed an electronic circuit which allows the recording of the evoked response within a few milliseconds of a pacing stimulus of 5 V and 0.5 ms duration being applied using a single unipolar, smooth platinum electrode of 14 mm2 surface area. The paced evoked response was measured using a total of 20 isolated rabbit heart preparations. Five were run for 8 hours and the remaining fifteen were run for 5 hours. Our results indicate that the waveform components of the evoked response remain stable while the preparation is viable, but that two of the time-related measurements change with loss of viability. A significant lengthening of the stimulus-R interval was seen together with a dramatic shortening of the R-T period. The net result of these changes was an overall reduction of 17% in the complex duration. In addition, we found the R-T shortening to be a sensitive measure of myocardial integrity. We conclude that the combination of our interface charge elimination circuit and the isolated heart preparation has proved a useful system for the investigation of the paced evoked potential. Furthermore, the loss of myocardial viability has a complex action on this response.

Oesophageal sensation assessed by electrical stimuli and brain evoked potentials--a new model for visceral nociception.

PubMed Central

Frøbert, O; Arendt-Nielsen, L; Bak, P; Funch-Jensen, P; Bagger, J P

1995-01-01

Sensory thresholds and brain evoked potentials were determined in 12 healthy volunteers using electrical stimulation of the oesophagus 28 and 38 cm from the nares. The peaks of the evoked potentials were designated N for negative deflections and P for positive. Continuous electrical stimulation (40 Hz) at the 38 cm position resembled heartburn (five of 12 subjects) while non-specific ('electrical') sensations were provoked at 28 cm (10 of 12). Thresholds of sensation and of pain were lower at the initial than the second determination, but did not differ with respect to stimulation site. The pain summation threshold to repeated stimuli (2 Hz, 5 stimuli) was determined for the first time in a viscus. This threshold was lower than the pain threshold to single stimuli at 38 cm (p < 0.02). Evoked potential latencies did not change significantly over a six month period while the N1/P2 amplitude was higher at the first measurement (p < 0.05). P1 and N1 latencies were significantly shorter 38 cm (medians 100 and 141 ms) than 28 cm from the nares (102 and 148 ms) (p = 0.04 and p = 0.008). Electrical stimulation of the oesophagus may serve as a human experimental model for visceral pain. Longer evoked potential latencies from the proximal compared with distal stimulations provide new information about the sensory pathways of the oesophagus. PMID:8549932

Habituation of Auditory Steady State Responses Evoked by Amplitude-Modulated Acoustic Signals in Rats

PubMed Central

Prado-Gutierrez, Pavel; Castro-Fariñas, Anisleidy; Morgado-Rodriguez, Lisbet; Velarde-Reyes, Ernesto; Martínez, Agustín D.; Martínez-Montes, Eduardo

2015-01-01

Generation of the auditory steady state responses (ASSR) is commonly explained by the linear combination of random background noise activity and the stationary response. Based on this model, the decrease of amplitude that occurs over the sequential averaging of epochs of the raw data has been exclusively linked to the cancelation of noise. Nevertheless, this behavior might also reflect the non-stationary response of the ASSR generators. We tested this hypothesis by characterizing the ASSR time course in rats with different auditory maturational stages. ASSR were evoked by 8-kHz tones of different supra-threshold intensities, modulated in amplitude at 115 Hz. Results show that the ASSR amplitude habituated to the sustained stimulation and that dishabituation occurred when deviant stimuli were presented. ASSR habituation increased as animals became adults, suggesting that the ability to filter acoustic stimuli with no-relevant temporal information increased with age. Results are discussed in terms of the current model of the ASSR generation and analysis procedures. They might have implications for audiometric tests designed to assess hearing in subjects who cannot provide reliable results in the psychophysical trials. PMID:26557360

Neurophysiological Changes Measured Using Somatosensory Evoked Potentials.

PubMed

Macerollo, Antonella; Brown, Matt J N; Kilner, James M; Chen, Robert

2018-05-01

Measurements of somatosensory evoked potentials (SEPs), recorded using electroencephalography during different phases of movement, have been fundamental in understanding the neurophysiological changes related to motor control. SEP recordings have also been used to investigate adaptive plasticity changes in somatosensory processing related to active and observational motor learning tasks. Combining noninvasive brain stimulation with SEP recordings and intracranial SEP depth recordings, including recordings from deep brain stimulation electrodes, has been critical in identifying neural areas involved in specific temporal stages of somatosensory processing. Consequently, this fundamental information has furthered our understanding of the maladaptive plasticity changes related to pathophysiology of diseases characterized by abnormal movements, such as Parkinson's disease, dystonia, and functional movement disorders. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Micro-field evoked potentials recorded from the porcine sub-dural cortical surface utilizing a microelectrode array.

PubMed

Kitzmiller, Joseph P; Hansford, Derek J; Fortin, Linda D; Obrietan, Karl H; Bergdall, Valerie K; Beversdorf, David Q

2007-05-15

A sub-dural surface microelectrode array designed to detect micro-field evoked potentials has been developed. The device is comprised of an array of 350-microm square gold contacts, with bidirectional spacing of 150 microm, contained within a polyimide Kapton material. Cytotoxicity testing suggests that the device is suitable for use with animal and human patients. Implementation of the device in animal studies revealed that reliable evoked potentials could be acquired. Further work will be needed to determine how these micro-field potentials, which demonstrate selectivity for one eye, relate to the distribution of the ocular dominance columns of the occipital cortex.

Micro-Field Evoked Potentials Recorded from the Porcine Sub-Dural Cortical Surface Utilizing a Microelectrode Array

PubMed Central

Kitzmiller, Joseph P.; Hansford, Derek J.; Fortin, Linda D.; Obrietan, Karl H.; Bergdall, Valerie K.

2007-01-01

A sub-dural surface microelectrode array designed to detect microfield evoked potentials has been developed. The device is comprised of an array of 350-micron square gold contacts, with bi-directional spacing of 150 microns, contained within a polyimide Kapton material. Cytotoxicity testing suggests that the device is suitable for use with animal and human patients. Implementation of the device in animal studies revealed that reliable evoked potentials could be acquired. Further work will be needed to determine how these microfield potentials, which demonstrate selectivity for one eye, relate to the distribution of the ocular dominance columns of the occipital cortex. PMID:17298849

Vestibular-evoked myogenic potential (VEMP) to evaluate cervical myelopathy in human T-cell lymphotropic virus type I infection.

PubMed

Felipe, Lilian; Gonçalves, Denise Utsch; Santos, Marco Aurélio Rocha; Proietti, Fernando Augusto; Ribas, João Gabriel Ramos; Carneiro-Proietti, Anna Bárbara; Lambertucci, José Roberto

2008-05-15

Cross-seccional analysis. To define the clinical usefulness of vestibular-evoked myogenic potential (VEMP) in detecting cervical medullar involvement related to human T-cell lymphotropic virus type 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP). VEMP is generated by acoustic or galvanic stimuli, passing through the vestibulo-spinal motor tract, the spinal nerves and recorded by means of surface electrodes on the sternocleidomastoid muscle. HAM/TSP is a progressive inflammatory myelopathy with predominant lesions at the thoracic spinal cord level, although the cervical spine can be affected. VEMP may be of value to investigate cervical myelopathy. Seventy-two individuals were evaluated of whom 30 HTLV-1 were seronegative and 42 HTLV-1 seropositive (22 asymptomatic, 10 with complaints of walking difficulty without definite HAM/TSP and 10 with definite HAM/TSP). VEMP was recorded using monaural delivered short tone burst (linear rise-fall 1 millisecond, plateau 2 milliseconds, 1 KHz) 118 dB NA, stimulation rate of 5 Hz, analysis time of 60 milliseconds, 200 stimuli, band pass filtered between 10 and 1.500 Hz. VEMP was normal in the seronegative group (30 controls). In the seropositive, abnormal VEMP was seen in 11 of 22 (50%) of the HTLV-1 asymptomatic carriers, in 7 of 10 (70%) of those with complaints of walking difficulty and in 8 of 10 (80%) of the HAM/TSP patients. In this last group, the pattern of response was different. No VEMP response was more frequent when compared with the HTLV-1 asymptomatic group (2-tailed P-value = 0.001). VEMP may possibly be useful to identify patients with cervical myelopathy and to distinguish variable degrees of functional damage. Minor injury would be related to latency prolongation and major injury to no potential-evoked response.

Anxiety affects the amplitudes of red and green color-elicited flash visual evoked potentials in humans.

PubMed

Hosono, Yuki; Kitaoka, Kazuyoshi; Urushihara, Ryo; Séi, Hiroyoshi; Kinouchi, Yohsuke

2014-01-01

It has been reported that negative emotional changes and conditions affect the visual faculties of humans at the neural level. On the other hand, the effects of emotion on color perception in particular, which are based on evoked potentials, are unknown. In the present study, we investigated whether different anxiety levels affect the color information processing for each of 3 wavelengths by using flash visual evoked potentials (FVEPs) and State-Trait Anxiety Inventory. In results, significant positive correlations were observed between FVEP amplitudes and state or trait anxiety scores in the long (sensed as red) and middle (sensed as green) wavelengths. On the other hand, short-wavelength-evoked FVEPs were not correlated with anxiety level. Our results suggest that negative emotional conditions may affect color sense processing in humans.

Testing the vestibular evoked myogenic potential (VEMP) to identify subclinical neurological alterations in different phases of human T-lymphotropic virus type 1 infection.

PubMed

Felipe, Lilian; Kingma, Herman; Lambertucci, José R; Carneiro-Proietti, Anna B; Gonçalves, Denise U

2013-04-01

The diagnosis of human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is based on clinical signs and the confirmation of HTLV-1 infection in the central nervous system. Electrophysiological tests may facilitate an earlier diagnosis of spinal cord involvement. Vestibular evoked myogenic potential (VEMP) testing evaluates the vestibulospinal tract, which is correlated with the motor tract; the target of damage by HAM/TSP. This study examines the subclinical neurological alterations related to HTLV-1 infection in individuals with asymptomatic HTLV-1 infections, possible HAM/TSP, and confirmed HAM/TSP. Vestibular evoked myogenic potential testing was performed at the beginning of the study and repeated every 6 months for 18 months. Ninety volunteers were selected for the study: 30 were HTLV-1 seronegative (the control group) and 60 were HTLV-1 seropositive (of these, 18 were asymptomatic, 25 had possible HAM/TSP, and 17 had confirmed HAM/TSP). The VEMP response was classified as normal or abnormal (latency prolongation or no response). A change in the VEMP response from normal to abnormal was the event of interest. To perform a survival analysis, the subjects with normal VEMP responses at the first assessment were selected. The results were analyzed blindly. Vestibular evoked myogenic potential was measured using short tone bursts as acoustic stimuli (1 kHz, 118 dBHL, a rise-fall of 1 millisecond, and a plateau of 2 milliseconds). The stimulation rate was 5 Hz, and the analysis time for each response was 60 milliseconds; each trial averaged 200 responses. The mean age of the subjects in the control group was 38 ± 11 years (median 35), and 13 (43%) were men. In the study group, the mean age was 51 ± 12 years (median 53), and 12 (20%) were men. An analysis of the survival curve indicated that the median time for a change in VEMP response from normal to abnormal was 18 months, which is in agreement with the slow

[Executive functioning and evoked potentials P300 pre- and post- treatment in attention deficit hyperactivity disorder].

PubMed

Roca, Patricia; Mulas, Fernando; Gandia, Rubén; Ortiz-Sánchez, Pedro; Abad, Luis

2013-02-22

Evoked potentials P300 and the analysis of executive functions have shown their utility in the monitoring of patients with symptoms of attention deficit hyperactivity disorder (ADHD). Neuropsychological profiles and evoked potentials P300 have been analysed for two groups of children with an ADHD treatment with atomoxetine and methylphenidate respectively. Correlations between P300 and the selected neuropsychological parameters are studied, and the differences between basal values and 1 year follow-up are analysed. Two groups were performed: a group of 22 children ADHD in the atomoxetine condition, and a group of 24 children ADHD in the methylphenidate condition. The results show a global improvement of all the parameters, in terms of executive function and P300 values in both, the atomoxetine and the methylphenidate group. Executive functions and evoked potentials P300 reflect an underlying processing and they are very useful in the clinical practice. This exploratory study shows the importance of designing personalized objective variables-based treatments.

Lack of habituation of evoked visual potentials in analytic information processing style: evidence in healthy subjects.

PubMed

Buonfiglio, Marzia; Toscano, M; Puledda, F; Avanzini, G; Di Clemente, L; Di Sabato, F; Di Piero, V

2015-03-01

Habituation is considered one of the most basic mechanisms of learning. Habituation deficit to several sensory stimulations has been defined as a trait of migraine brain and also observed in other disorders. On the other hand, analytic information processing style is characterized by the habit of continually evaluating stimuli and it has been associated with migraine. We investigated a possible correlation between lack of habituation of evoked visual potentials and analytic cognitive style in healthy subjects. According to Sternberg-Wagner self-assessment inventory, 15 healthy volunteers (HV) with high analytic score and 15 HV with high global score were recruited. Both groups underwent visual evoked potentials recordings after psychological evaluation. We observed significant lack of habituation in analytical individuals compared to global group. In conclusion, a reduced habituation of visual evoked potentials has been observed in analytic subjects. Our results suggest that further research should be undertaken regarding the relationship between analytic cognitive style and lack of habituation in both physiological and pathophysiological conditions.

Analysis of electrically evoked compound action potential of the auditory nerve in children with bilateral cochlear implants.

PubMed

Caldas, Fernanda Ferreira; Cardoso, Carolina Costa; Barreto, Monique Antunes de Souza Chelminski; Teixeira, Marina Santos; Hilgenberg, Anacléia Melo da Silva; Serra, Lucieny Silva Martins; Bahmad Junior, Fayez

2016-01-01

The cochlear implant device has the capacity to measure the electrically evoked compound action potential of the auditory nerve. The neural response telemetry is used in order to measure the electrically evoked compound action potential of the auditory nerve. To analyze the electrically evoked compound action potential, through the neural response telemetry, in children with bilateral cochlear implants. This is an analytical, prospective, longitudinal, historical cohort study. Six children, aged 1-4 years, with bilateral cochlear implant were assessed at five different intervals during their first year of cochlear implant use. There were significant differences in follow-up time (p=0.0082) and electrode position (p=0.0019) in the T-NRT measure. There was a significant difference in the interaction between time of follow-up and electrode position (p=0.0143) when measuring the N1-P1 wave amplitude between the three electrodes at each time of follow-up. The electrically evoked compound action potential measurement using neural response telemetry in children with bilateral cochlear implants during the first year of follow-up was effective in demonstrating the synchronized bilateral development of the peripheral auditory pathways in the studied population. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Segmental somatosensory-evoked potentials as a diagnostic tool in chronic inflammatory demyelinating polyneuropathies, and other sensory neuropathies.

PubMed

Koutlidis, R M; Ayrignac, X; Pradat, P-F; Le Forestier, N; Léger, J-M; Salachas, F; Maisonobe, T; Fournier, E; Viala, K

2014-09-01

Somatosensory-evoked potentials with segmental recordings were performed with the aim of distinguishing chronic inflammatory demyelinating polyneuropathy from other sensory neuropathies. Four groups of 20 subjects each corresponded to patients with (1) possible sensory chronic inflammatory demyelinating polyneuropathy, (2) patients with sensory polyneuropathy of unknown origin, (3) patients with amyotrophic lateral sclerosis and (4) normal subjects. The patients selected for this study had preserved sensory potentials on electroneuromyogram and all waves were recordable in evoked potentials. Somatosensory-evoked potentials evaluations were carried out by stimulation of the posterior tibial nerve at the ankle, recording peripheral nerve potential in the popliteal fossa, radicular potential and spinal potential at the L4-L5 and T12 levels, and cortical at C'z, with determination of distal conduction time, proximal and radicular conduction time and central conduction time. In the group of chronic inflammatory demyelinating polyneuropathy, 80% of patients had abnormal conduction in the N8-N22 segment and 95% had abnormal N18-N22 conduction time. In the group of neuropathies, distal conduction was abnormal in most cases, whereas 60% of patients had no proximal abnormality. None of the patients in the group of amyotrophic lateral sclerosis had an abnormal N18-N22 conduction time. Somatosensory-evoked potentials with segmental recording can be used to distinguish between atypical sensory chronic inflammatory demyelinating polyneuropathy and other sensory neuropathies, at the early stage of the disease. Graphical representation of segmental conduction times provides a rapid and accurate visualization of the profile of each patient. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Steady-state visual evoked potential (SSVEP)-based communication: impact of harmonic frequency components

NASA Astrophysics Data System (ADS)

Müller-Putz, Gernot R.; Scherer, Reinhold; Brauneis, Christian; Pfurtscheller, Gert

2005-12-01

Brain-computer interfaces (BCIs) can be realized on the basis of steady-state evoked potentials (SSEPs). These types of brain signals resulting from repetitive stimulation have the same fundamental frequency as the stimulation but also include higher harmonics. This study investigated how the classification accuracy of a 4-class BCI system can be improved by incorporating visually evoked harmonic oscillations. The current study revealed that the use of three SSVEP harmonics yielded a significantly higher classification accuracy than was the case for one or two harmonics. During feedback experiments, the five subjects investigated reached a classification accuracy between 42.5% and 94.4%.

Steady-state visual evoked potential (SSVEP)-based communication: impact of harmonic frequency components.

PubMed

Müller-Putz, Gernot R; Scherer, Reinhold; Brauneis, Christian; Pfurtscheller, Gert

2005-12-01

Brain-computer interfaces (BCIs) can be realized on the basis of steady-state evoked potentials (SSEPs). These types of brain signals resulting from repetitive stimulation have the same fundamental frequency as the stimulation but also include higher harmonics. This study investigated how the classification accuracy of a 4-class BCI system can be improved by incorporating visually evoked harmonic oscillations. The current study revealed that the use of three SSVEP harmonics yielded a significantly higher classification accuracy than was the case for one or two harmonics. During feedback experiments, the five subjects investigated reached a classification accuracy between 42.5% and 94.4%.

Unknown Pseudocholinesterase Deficiency in a Patient Undergoing TIVA with Planned Motor Evoked Potential Monitoring: A Case Report.

PubMed

Binkley, Candace

2016-06-01

Pseudocholinesterase abnormalities are a genetic cause of aberrant metabolism of the depolarizing muscle relaxant succinylcholine. This article examines a case where succinylcholine was chosen to facilitate intubation due to its ultra short duration and the request of the surgeon to monitor motor evoked potentials. Following succinylcholine administration the neurophysiologist was unable to obtain motor evoked potentials. This case study highlights the intraoperative and postoperative management of an elderly patient with an unknown pseudocholinesterase deficiency.

Long latency auditory evoked potentials in children with cochlear implants: systematic review.

PubMed

Silva, Liliane Aparecida Fagundes; Couto, Maria Inês Vieira; Matas, Carla Gentile; Carvalho, Ana Claudia Martinho de

2013-11-25

The aim of this study was to analyze the findings on Cortical Auditory Evoked Potentials in children with cochlear implant through a systematic literature review. After formulation of research question and search of studies in four data bases with the following descriptors: electrophysiology (eletrofisiologia), cochlear implantation (implante coclear), child (criança), neuronal plasticity (plasticidade neuronal) and audiology (audiologia), were selected articles (original and complete) published between 2002 and 2013 in Brazilian Portuguese or English. A total of 208 studies were found; however, only 13 contemplated the established criteria and were further analyzed; was made data extraction for analysis of methodology and content of the studies. The results described suggest rapid changes in P1 component of Cortical Auditory Evoked Potentials in children with cochlear implants. Although there are few studies on the theme, cochlear implant has been shown to produce effective changes in central auditory path ways especially in children implanted before 3 years and 6 months of age.

Continuous time wavelet entropy of auditory evoked potentials.

PubMed

Cek, M Emre; Ozgoren, Murat; Savaci, F Acar

2010-01-01

In this paper, the continuous time wavelet entropy (CTWE) of auditory evoked potentials (AEP) has been characterized by evaluating the relative wavelet energies (RWE) in specified EEG frequency bands. Thus, the rapid variations of CTWE due to the auditory stimulation could be detected in post-stimulus time interval. This approach removes the probability of missing the information hidden in short time intervals. The discrete time and continuous time wavelet based wavelet entropy variations were compared on non-target and target AEP data. It was observed that CTWE can also be an alternative method to analyze entropy as a function of time. 2009 Elsevier Ltd. All rights reserved.

Clinical application of vestibular evoked myogenic potential (VEMP).

PubMed

Murofushi, Toshihisa

2016-08-01

The author reviewed clinical aspects of vestibular evoked myogenic potentials (VEMPs). Now two types of VEMPs are available. The first one is cervical VEMP, which is recorded in the sternocleidomastoid muscle and predominantly reflects sacculo-collic reflex. The other is ocular VEMP, which is usually recorded below the lower eye lid and predominantly reflects utriculo-ocular reflex. VEMPs play important roles not only for assessment of common vestibular diseases but also for establishment of new clinical entities. Clinical application in Meniere's disease, vestibular neuritis, benign paroxysmal positional vertigo, vestibular migraine, idiopathic otolithic vertigo, and central vertigo/dizziness was reviewed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The semantic component of the evoked potential of differentiation.

PubMed

Izmailov, Chingis A; Korshunova, Svetlana G; Sokolov, Yevgeniy N

2008-05-01

This work analyzes data from recordings of (occipital and temporal) cortical evoked potentials (called evoked potentials of differentiation (EPD) occurring in humans in response to an abrupt substitution of stimuli. As stimuli we used three groups of words: the names of the ten basic colors taken from Newton's color circle; the names of seven basic emotions forming Shlossberg's circle of emotions; and seven nonsense words comprised of random combinations of letters. Within each group of word stimuli we constructed a matrix of the differences between the amplitudes of mid-latency components of EPD for each pair of words. This matrix was analyzed using the method of multidimensional scaling. As a result of this analysis we were able to distinguish the semantic and configurational components of EPD amplitude. The semantic component of EPD amplitude was evaluated by comparing structure of the data obtained to the circular structures of emotion and color names. The configurational component was evaluated on the basis of the attribute of word length (number of letters). It was demonstrated that the semantic component of the EPD can only be detected in the left occipital lead at an interpeak amplitude of P120-N180. The configurational component is reflected in the occipital and temporal leads to an identical extent, but only in the amplitude of a later (N180-P230) component of the EPD. The results obtained are discussed in terms of the coding of categorized, configurational, and semantic attributes of a visual stimulus.

High frequency bone conduction auditory evoked potentials in the guinea pig: Assessing cochlear injury after ossicular chain manipulation.

PubMed

Bergin, M J; Bird, P A; Vlajkovic, S M; Thorne, P R

2015-12-01

Permanent high frequency (>4 kHz) sensorineural hearing loss following middle ear surgery occurs in up to 25% of patients. The aetiology of this loss is poorly understood and may involve transmission of supra-physiological forces down the ossicular chain to the cochlea. Investigating the mechanisms of this injury using animal models is challenging, as evaluating cochlear function with evoked potentials is confounded when ossicular manipulation disrupts the normal air conduction (AC) pathway. Bone conduction (BC) using clinical bone vibrators in small animals is limited by poor transducer output at high frequencies sensitive to trauma. The objectives of the present study were firstly to evaluate a novel high frequency bone conduction transducer with evoked auditory potentials in a guinea pig model, and secondly to use this model to investigate the impact of middle ear surgical manipulation on cochlear function. We modified a magnetostrictive device as a high frequency BC transducer and evaluated its performance by comparison with a calibrated AC transducer at frequencies up to 32 kHz using the auditory brainstem response (ABR), compound action potential (CAP) and summating potential (SP). To mimic a middle ear traumatising stimulus, a rotating bur was brought in to contact with the incudomalleal complex and the effect on evoked cochlear potentials was observed. BC-evoked potentials followed the same input-output function pattern as AC potentials for all ABR frequencies. Deterioration in CAP and SP thresholds was observed after ossicular manipulation. It is possible to use high frequency BC to evoke responses from the injury sensitive basal region of the cochlea and so not rely on AC with the potential confounder of conductive hearing loss. Ongoing research explores how these findings evolve over time, and ways in which injury may be reduced and the cochlea protected during middle ear surgery. Copyright © 2015 Elsevier B.V. All rights reserved.

Applications of pain-related evoked potentials and short-latency somatosensory evoked potentials in acupuncture research: a narrative review.

PubMed

Lin, Chi; Ma, Liangxiao; Zhu, Shipeng; Hu, Nijuan; Wang, Pei; Zhang, Peng; Qi, Dandan; Hao, Jie; Li, Jing; Xin, Siyuan; Zhu, Jiang

2015-10-01

To review and discuss the Chinese and English literature on the use of pain-related evoked potentials (PREP) and short-latency somatosensory EP (SLSEP) in acupuncture research. China National Knowledge Infrastructure Database and MEDLINE were searched for the following key words: acupuncture and PREP or SLSEP. Thirty-seven articles were included in the review. Researchers usually use PREPs to study the analgesic effect of acupuncture, observe influential factors, or for mechanistic exploration. In the SLSEP studies, researchers focused on response characteristics of acupuncture, acupoint specificity, and influential factors of the treatment. There were some problems with the study design and conclusions. Researchers could use PREP and SLSEP to objectively validate the effects of acupuncture and explore its mechanisms using nerve electrophysiology. Further studies can benefit from observing more acupoints' effects using PREPs or SLSEPs and investigating the placebo effect of acupuncture.

Somatosensory evoked potentials in patients with hypocalcaemia after parathyroidectomy.

PubMed

Kanda, F; Jinnai, J; Fujita, T

1988-01-01

The effects of hypocalcaemia on somatosensory evoked potentials (SEPs) were studied in five patients after parathyroidectomy. Despite normal latencies the mean value of amplitudes of the SEPs in hypocalcaemic patients was greater than that in normocalcaemic subjects. Recovery functions of the SEPs showed a significant decrease in hypocalcaemic patients at interstimulus intervals of about 10 ms compared with those in normocalcaemic patients and in normal volunteers. Recovery functions appear to be a valid indicator of synaptic efficacy, especially for evaluation of the reduction in conduction efficacy of the central nervous system in hypocalcaemia.

Diagnostic value of conventional visual evoked potentials applied to patients with multiple sclerosis.

PubMed

Balnytė, Renata; Ulozienė, Ingrida; Rastenytė, Daiva; Vaitkus, Antanas; Malcienė, Lina; Laučkaitė, Kristina

2011-01-01

The aim of this study was to determine the sensitivity and specificity of this classical technique employed at the Hospital of Lithuanian University of Health Sciences for the patients with multiple sclerosis and to assess its possible correlations with affected neurological systems. Pattern shift visual evoked potentials were recorded in 63 patients with multiple sclerosis, 17 (27%) of whom had a history of optic neuritis, and in 63 control patients with other neurological diseases. The latencies and amplitudes of P100 were measured. In total, 126 patients were referred to the inpatient department of neurology for differential diagnosis of demyelinating disorders between January and December of 2007. Abnormalities of visual evoked potentials were observed by 73% more frequently in patients with multiple sclerosis than in control patients (α=0.05, β<0.01). The combined monocular/interocular test showed a specificity of 90.5% and a sensitivity of 82.5%. The probability of an affection of the pyramidal system was 5 times greater (95% CI, 2.2-11.0; P<0.01) and the probability of the optic pathways involvement was 4.8 times greater (95% CI, 1.9-11.9; P<0.01) in patients with multiple sclerosis than in controls. Conventional visual evoked potentials must be reappraised in light of their diagnostic value in multiple sclerosis given their high diagnostic efficiency, relatively easy, short, and cheap implementation, and easy availability in everyday clinical practice.

Gap-induced reductions of evoked potentials in the auditory cortex: A possible objective marker for the presence of tinnitus in animals.

PubMed

Berger, Joel I; Owen, William; Wilson, Caroline A; Hockley, Adam; Coomber, Ben; Palmer, Alan R; Wallace, Mark N

2018-01-15

Animal models of tinnitus are essential for determining the underlying mechanisms and testing pharmacotherapies. However, there is doubt over the validity of current behavioural methods for detecting tinnitus. Here, we applied a stimulus paradigm widely used in a behavioural test (gap-induced inhibition of the acoustic startle reflex GPIAS) whilst recording from the auditory cortex, and showed neural response changes that mirror those found in the behavioural tests. We implanted guinea pigs (GPs) with electrocorticographic (ECoG) arrays and recorded baseline auditory cortical responses to a startling stimulus. When a gap was inserted in otherwise continuous background noise prior to the startling stimulus, there was a clear reduction in the subsequent evoked response (termed gap-induced reductions in evoked potentials; GIREP), suggestive of a neural analogue of the GPIAS test. We then unilaterally exposed guinea pigs to narrowband noise (left ear; 8-10 kHz; 1 h) at one of two different sound levels - either 105 dB SPL or 120 dB SPL - and recorded the same responses seven-to-ten weeks following the noise exposure. Significant deficits in GIREP were observed for all areas of the auditory cortex (AC) in the 120 dB-exposed GPs, but not in the 105 dB-exposed GPs. These deficits could not simply be accounted for by changes in response amplitudes. Furthermore, in the contralateral (right) caudal AC we observed a significant increase in evoked potential amplitudes across narrowband background frequencies in both 105 dB and 120 dB-exposed GPs. Taken in the context of the large body of literature that has used the behavioural test as a demonstration of the presence of tinnitus, these results are suggestive of objective neural correlates of the presence of noise-induced tinnitus and hyperacusis. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

[A Case of Left Vertebral Artery Aneurysm Showing Evoked Potentials on Bilateral Electrode by the Left Vagus Nerve Stimulation to Electromyographic Tracheal Tube].

PubMed

Kadoya, Tatsuo; Uehara, Hirofumi; Yamamoto, Toshinori; Shiraishi, Munehiro; Kinoshita, Yuki; Joyashiki, Takeshi; Enokida, Kengo

2016-02-01

Previously, we reported a case of brainstem cavernous hemangioma showing false positive responses to electromyographic tracheal tube (EMG tube). We concluded that the cause was spontaneous respiration accompanied by vocal cord movement. We report a case of left vertebral artery aneurysm showing evoked potentials on bilateral electrodes by the left vagus nerve stimulation to EMG tube. An 82-year-old woman underwent clipping of a left unruptured vertebral artery-posterior inferior cerebellar artery aneurysm. General anesthesia was induced with remifentanil, propofol and suxamethonium, and was maintained with oxygen, air, remifentanil and propofol. We monitored somatosensory evoked potentials, motor evoked potentials, and electromyogram of the vocal cord. When the manipulation reached brainstem and the instrument touched the left vagus nerve, evoked potentials appeared on bilateral electrodes. EMG tube is equipped with two electrodes on both sides. We concluded that the left vagus nerve stimulation generated evoked potentials of the left laryngeal muscles, and they were simultaneously detected as potential difference between two electrodes on both sides. EMG tube is used to identify the vagus nerve. However, it is necessary to bear in mind that each vagus nerve stimulation inevitably generates evoked potentials on bilateral electrodes.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

PubMed Central

Barboni, M.T.S.; Gomes, B.D.; Souza, G.S.; Rodrigues, A.R.; Ventura, D.F.; Silveira, L.C.L.

2013-01-01

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5° × 5°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus. PMID:23369980

Combined ocular and cervical vestibular evoked myogenic potential in individuals with vestibular hyporeflexia and in patients with Ménière's disease.

PubMed

Silva, Tatiana Rocha; de Resende, Luciana Macedo; Santos, Marco Aurélio Rocha

The vestibular evoked myogenic potential is a potential of mean latency that measures the muscle response to auditory stimulation. This potential can be generated from the contraction of the sternocleidomastoid muscle and also from the contraction of extraocular muscles in response to high-intensity sounds. This study presents a combined or simultaneous technique of cervical and ocular vestibular evoked myogenic potential in individuals with changes in the vestibular system, for use in otoneurologic diagnosis. To characterize the records and analyze the results of combined cervical and ocular VEMP in individuals with vestibular hyporeflexia and in those with Ménière's disease. The study included 120 subjects: 30 subjects with vestibular hyporeflexia, 30 with Ménière's disease, and 60 individuals with normal hearing. Data collection was performed by simultaneously recording the cervical and ocular vestibular evoked myogenic potential. There were differences between the study groups (individuals with vestibular hyporeflexia and individuals with Ménière's disease) and the control group for most of wave parameters in combined cervical and ocular vestibular evoked myogenic potential. For cervical vestibular evoked myogenic potential, it was observed that the prolongation of latency of the P13 and N23 waves was the most frequent finding in the group with vestibular hyporeflexia and in the group with Ménière's disease. For ocular vestibular evoked myogenic potential, prolonged latency of N10 and P15 waves was the most frequent finding in the study groups. Combined cervical and ocular vestibular evoked myogenic potential presented relevant results for individuals with vestibular hyporeflexia and for those with Ménière's disease. There were differences between the study groups and the control group for most of the wave parameters in combined cervical and ocular vestibular evoked myogenic potential. Copyright © 2016 Associação Brasileira de Otorrinolaringologia

Investigation of brachial plexus traction lesions by peripheral and spinal somatosensory evoked potentials.

PubMed Central

Jones, S J

1979-01-01

Peripheral, spinal and cortical somatosensory evoked potentials were recorded in 26 patients with unilateral traction injuries of the brachial plexus ganglia. Of 10 cases explored surgically the recordings correctly anticipated the major site of the lesion in eight. PMID:422958

Towards neural correlates of auditory stimulus processing: A simultaneous auditory evoked potentials and functional magnetic resonance study using an odd-ball paradigm

PubMed Central

Milner, Rafał; Rusiniak, Mateusz; Lewandowska, Monika; Wolak, Tomasz; Ganc, Małgorzata; Piątkowska-Janko, Ewa; Bogorodzki, Piotr; Skarżyński, Henryk

2014-01-01

Background The neural underpinnings of auditory information processing have often been investigated using the odd-ball paradigm, in which infrequent sounds (deviants) are presented within a regular train of frequent stimuli (standards). Traditionally, this paradigm has been applied using either high temporal resolution (EEG) or high spatial resolution (fMRI, PET). However, used separately, these techniques cannot provide information on both the location and time course of particular neural processes. The goal of this study was to investigate the neural correlates of auditory processes with a fine spatio-temporal resolution. A simultaneous auditory evoked potentials (AEP) and functional magnetic resonance imaging (fMRI) technique (AEP-fMRI), together with an odd-ball paradigm, were used. Material/Methods Six healthy volunteers, aged 20–35 years, participated in an odd-ball simultaneous AEP-fMRI experiment. AEP in response to acoustic stimuli were used to model bioelectric intracerebral generators, and electrophysiological results were integrated with fMRI data. Results fMRI activation evoked by standard stimuli was found to occur mainly in the primary auditory cortex. Activity in these regions overlapped with intracerebral bioelectric sources (dipoles) of the N1 component. Dipoles of the N1/P2 complex in response to standard stimuli were also found in the auditory pathway between the thalamus and the auditory cortex. Deviant stimuli induced fMRI activity in the anterior cingulate gyrus, insula, and parietal lobes. Conclusions The present study showed that neural processes evoked by standard stimuli occur predominantly in subcortical and cortical structures of the auditory pathway. Deviants activate areas non-specific for auditory information processing. PMID:24413019

[Intraoperative pain stimuli change somatosensory evoked potentials, but not auditory evoked potentials during isoflurane/nitrous oxide anesthesia].

PubMed

Rundshagen, I; Kochs, E; Bischoff, P; Schulte am Esch, J

1997-10-01

Evoked potentials are used for intraoperative monitoring to assess changes of cerebral function. This prospective randomised study assesses the influence of surgical stimulation on midlatency components of somatosensory (SEPs) and auditory evoked potentials (AEPs) in anaesthetised patients. After approval of the Ethics Committee and written informed consent 36 orthopaedic patients (34 +/- 15 y, 73 +/- 14 kg. 1.71 +/- 0.07 m, ASA I-II) were randomly included in the study. Anaesthesia was induced with 1.5 micrograms/kg fentanyl, 0.3 mg/kg etomidate and 0.1 mg/kg vecuronium. The lungs were intubated and patients normoventilated in steady state anaesthesia with isoflurane (end-tidal 0.6%) and 66% nitrous oxide. 18 patients (group 1) were assigned to the SEP group: median nerve stimulation, recording at Erb, C 6 and the contralateral somatosensory cortex (N20, P25, N35) vs Fz. AEPs were recorded in group 2 (n = 18): binaural stimulation, recording at Cz versus linked mastoid (V, Na, Pa, Nb). Recordings were performed during 30 min before the start of surgery (baseline: BL), at skin incision (SURG1) and at the preparation of the periost (SURG2). Heart rate, mean arterial blood pressure, oxygen saturation, endtidal pCO2 and isoflurane (PetISO) concentrations were registered simultaneously. Data were analysed by one-way analysis of variance. Post hoc comparison were made by Mann-Whitney U-Wilcoxon Rank Sum Test with p < 0.05 significant. During steady state isoflurane anaesthesia surgical stimulation (SURG2) resulted in significant increases of N20 P25 amplitudes compared with BL (BL: 1.4 +/- 0.7 microV; SURG2: 2.0 +/- 0.8 microV; p < 0.05). Latencies of SEPs and midlatency components of AEPs did not change over time. There were no differences in autonomic parameters between SEP and AEP groups. MAP increased from 76 +/- 6 mmHg at BL to 93 +/- 16 mmHg at SURG1 and 96 +/- 17 mmHg at SURG2 (n = 36; p < 0.05). HR increased from BL (60 +/- 8 beats/min) to SURG2 (76 +/- 12 beats

Neuronal current magnetic resonance imaging of evoked potentials and neural oscillations

NASA Astrophysics Data System (ADS)

Jiang, Xia

Despite its great success, the current functional magnetic resonance imaging (MRI) technique relies on changes in cerebral hemodynamic parameters to infer the underlying neural activities, and as a result is limited in its spatial and temporal resolutions. In this dissertation, we discuss the feasibility of neuronal current MRI (nc-MRI), a novel technique in which the small magnetic field changes caused by neuronal electrical activities are directly measured by MRI. Two studies are described. In the first study, we investigated the feasibility of detecting the magnetic field produced by sensory evoked potentials. To eliminate the blood-oxygen-level-dependent (BOLD) effect on the MRI signal, which confounded most previous studies, an octopus visual system model was developed, which, for the first time, allowed for an in vivo investigation of nc-MRI in a BOLD-free environment. Electrophysiological responses were measured in the octopus retina and optical lobe to guide the nc-MRI acquisition. Our results indicated that no nc-MRI signal change related to neuronal activation could be detected at 0.2°/0.2% threshold for signal phase/magnitude respectively, while robust electrophysiological responses were recorded. In the second study, we discuss the feasibility of detecting neural oscillations with MRI, Based on previous studies, a novel approach was proposed in which an external oscillatory field was exploited as the excitation pulse under a spin-locked condition. This approach has the advantages of increased sensitivity and lowered physiological noise. Successful detection of sub-nanotesla field was demonstrated in phantom. Our results suggest that evoked potentials are too weak for nc-MRI detection with the current hardware, and that previous positive findings were likely due to hemodynamic confounders. On the other hand, oscillatory magnetic field can be efficiently detected in phantom. Given the stronger equivalent current dipoles produced by neural oscillations

Visual and brainstem auditory evoked potentials in children with obesity.

PubMed

Akın, Onur; Arslan, Mutluay; Akgün, Hakan; Yavuz, Süleyman Tolga; Sarı, Erkan; Taşçılar, Mehmet Emre; Ulaş, Ümit Hıdır; Yeşilkaya, Ediz; Ünay, Bülent

2016-03-01

The aim of our study is to investigate alterations in visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) in children with obesity. A total of 96 children, with a mean age of 12.1±2.0 years (range 9-17 years, 63 obese and 33 age and sex-matched control subjects) were included in the study. Laboratory tests were performed to detect insulin resistance (IR) and dyslipidemia. The latencies and amplitudes of VEP and BAEP were measured in healthy and obese subjects. The VEP P100, BAEP interpeak latency (IPL) I-III and IPL I-V averages of obese children were significantly longer than the control subjects. When the obese group was divided into two subgroups, those with IR and without IR, BAEP wave I, wave III and P100 wave latencies were found to be longer in the group with IR. A statistically significant correlation was observed between BAEP wave I latency, IPL I-V, IPL I-III and the homeostatic model assessment insulin resistance (HOMA IR) index and fasting insulin level. Our findings suggest that VEP and BAEP can be used to determine early subclinical on auditory and visual functions of obese children with insulin resistance. Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

Acoustic pollution in hospital environments

NASA Astrophysics Data System (ADS)

Olivera, J. M.; Rocha, L. A.; Rotger, V. I.; Herrera, M. C.

2011-12-01

There are many different services within a hospital. This means different types of noise which can be considered as acoustic pollution. Knowing that preterm infants exposed to high amounts of noise in the NICU are at a much higher risk because of their neurologic immaturity and physiologic instability, that excessive levels of noise also affect the persons and it can also impede some studies on patients, it was proposed to evaluate the Sound Pressure Level in some services of the Instituto de Maternidad, Tucumán, Argentina. There were evaluated the Level III NICU, the laundry service, a physical space destined for a service of evoked potential and a neonatal incubator under working conditions. The measurements were performed with a type II sonometer (CENTER 322) and it was also used an incubator analyzer (FLUKE INCU) for the incubator. The average values obtained were of 63.6 dBA for the NICU, 82.5dBA for the laundry room, 52.7 dBA for the evoked potential room and 62.8 dBA in the inside of the incubator under 64 dBA in the outside. The reports were documented in compliance with the appropriate standards.

Auditory Evoked Potentials as a Function of Sleep Deprivation and Recovery Sleep

DTIC Science & Technology

1985-09-29

present research: They relate to the effects of: a) 48-hours of sleep deprivation on endogenous event related potentials (ERPs); b) circadian rhythms on...the study were: decreases in amplitude for N2, P3 and N2P3 across the reprivation period; a circadian rhythm was apparent for both ERP recordings and...of cortical evoked response potentials (ERPs)? 2) How do circadian rhythms affect ERPS under conditions of sleep deprivation? 3) How do different

[Recommendations for the clinical use of motor evoked potentials in multiple sclerosis].

PubMed

Fernández, V; Valls-Sole, J; Relova, J L; Raguer, N; Miralles, F; Dinca, L; Taramundi, S; Costa-Frossard, L; Ferrandiz, M; Ramió-Torrentà, Ll; Villoslada, P; Saiz, A; Calles, C; Antigüedad, A; Alvarez-Cermeño, J C; Prieto, J M; Izquierdo, G; Montalbán, X; Fernández, O

2013-09-01

To establish clinical guidelines for the clinical use and interpretation of motor evoked potentials (MEP) in diagnosing and monitoring patients with multiple sclerosis (MS). Recommendations for MEP use and interpretation will help us rationalise and optimise resources used in MS patient diagnosis and follow up. We completed an extensive literature review and pooled our own data to produce a consensus statement with recommendations for the clinical use of MEPs in the study of MS. MEPs, in addition to spinal and cranial magnetic resonance imaging (MRI), help us diagnose and assess MS patients whose disease initially presents as spinal cord syndrome and those with non-specific brain MRI findings, or a normal brain MRI and clinical signs of MS. Whenever possible, a multimodal evoked potential study should be performed on patients with suspected MS in order to demonstrate involvement of the motor pathway which supports a diagnosis of dissemination in space. Copyright © 2012 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

Implementation of a microprocessor-based visual-evoked cortical potential recording and analysis system.

PubMed

Wilson, A; Fram, D; Sistar, J

1981-06-01

An Imsai 8080 microcomputer is being used to simultaneously generate a color graphics stimulus display and to record visual-evoked cortical potentials. A brief description of the hardware and software developed for this system is presented. Data storage and analysis techniques are also discussed.

Auditory evoked potential measurements in elasmobranchs

NASA Astrophysics Data System (ADS)

Casper, Brandon; Mann, David

2005-04-01

Auditory evoked potentials (AEP) were first used to examine hearing in elasmobranchs by Corwin and Bullock in the late 1970s and early 1980s, marking the first time AEPs had been measured in fishes. Results of these experiments identified the regions of the ear and brain in which sound is processed, though no actual hearing thresholds were measured. Those initial experiments provided the ground work for future AEP experiments to measure fish hearing abilities in a manner that is much faster and more convenient than classical conditioning. Data will be presented on recent experiments in which AEPs were used to measure the hearing thresholds of two species of elasmobranchs: the nurse shark, Ginglymostoma cirratum, and the yellow stingray, Urobatis jamaicencis. Audiograms were analyzed and compared to previously published audiograms obtained using classical conditioning with results indicating that hearing thresholds were similar for the two methods. These data suggest that AEP testing is a viable option when measuring hearing in elasmobranchs and can increase the speed in which future hearing measurements can be obtained.

Short- and long-latency auditory evoked potentials in individuals with vestibular dysfunction.

PubMed

Santos Filha, Valdete Alves Valentins Dos; Bruckmann, Mirtes; Garcia, Michele Vargas

2018-01-01

Purpose Evaluate the auditory pathway at the brainstem and cortical levels in individuals with peripheral vestibular dysfunction. Methods The study sample was composed 19 individuals aged 20-80 years that presented exam results suggestive of Peripheral Vestibular Disorder (PVD) or Vestibular Dysfunction (VD). Participants underwent evaluation of the auditory pathway through Brainstem Auditory Evoked Potentials (BAEP) (short latency) and P1, N1, P2, N2, and P300 cortical potentials (long latency). Results Nine individuals presented diagnosis of VD and 10 participants were diagnosed with PVD. The overall average of the long latency potentials of the participants was within the normal range, whereas an increased mean was observed in the short latency of waves III and V of the left ear, as well as in the I - III interpeak interval of both ears. Association of the auditory potentials with VD and PVD showed statistically significant correlation only in the III - V interpeak interval of the right ear for short latency. Comparison between the long and short latencies in the groups showed differences between VD and PVD, but without statistical significance. Conclusion No statistically significant correlation was observed between VD/PVD and the auditory evoked potentials; however, for the long latency potentials, individuals with VD presented higher latency in P1, N1, P2, and N2, where as participants with PVD showed higher latency in P300. In the short latency potentials, there was an increase in the absolute latencies in the VD group and in the interpeak intervals in the PVD group.

Lateral geniculate body evoked potentials elicited by visual and electrical stimulation.

PubMed

Choi, Chang Wook; Kim, Pan Sang; Shin, Sun Ae; Yang, Ji Yeon; Yang, Yun Sik

2014-08-01

Blind individuals who have photoreceptor loss are known to perceive phosphenes with electrical stimulation of their remaining retinal ganglion cells. We proposed that implantable lateral geniculate body (LGB) stimulus electrode arrays could be used to generate phosphene vision. We attempted to refine the basic reference of the electrical evoked potentials (EEPs) elicited by microelectrical stimulations of the optic nerve, optic tract and LGB of a domestic pig, and then compared it to visual evoked potentials (VEPs) elicited by short-flash stimuli. For visual function measurement, VEPs in response to short-flash stimuli on the left eye of the domestic pig were assessed over the visual cortex at position Oz with the reference electrode at Fz. After anesthesia, linearly configured platinum wire electrodes were inserted into the optic nerve, optic track and LGB. To determine the optimal stimulus current, EEPs were recorded repeatedly with controlling the pulse and power. The threshold of current and charge density to elicit EEPs at 0.3 ms pulse duration was about ±10 µA. Our experimental results showed that visual cortex activity can be effectively evoked by stimulation of the optic nerve, optic tract and LGB using penetrating electrodes. The latency of P1 was more shortened as the electrical stimulation was closer to LGB. The EEPs of two-channel in the visual cortex demonstrated a similar pattern with stimulation of different spots of the stimulating electrodes. We found that the LGB-stimulated EEP pattern was very similar to the simultaneously generated VEP on the control side, although implicit time deferred. EEPs and VEPs derived from visual-system stimulation were compared. The LGB-stimulated EEP wave demonstrated a similar pattern to the VEP waveform except implicit time, indicating prosthetic-based electrical stimulation of the LGB could be utilized for the blind to perceive vision of phosphenes.

Development of somatosensory-evoked potentials in foetal sheep: effects of betamethasone.

PubMed

Anegroaie, P; Frasch, M G; Rupprecht, S; Antonow-Schlorke, I; Müller, T; Schubert, H; Witte, O W; Schwab, M

2017-05-01

Antenatal glucocorticoids are used to accelerate foetal lung maturation in babies threatened with premature labour. We examined the influence of glucocorticoids on functional and structural maturation of the central somatosensory pathway in foetal sheep. Somatosensory-evoked potentials (SEP) reflect processing of somatosensory stimuli. SEP latencies are determined by afferent stimuli transmission while SEP amplitudes reveal cerebral processing. After chronic instrumentation of foetal sheep, mothers received saline (n = 9) or three courses of betamethasone (human equivalent dose of 2 × 110 μg kg -1 betamethasone i.m. 24 h apart, n = 12) at 0.7, 0.75 and 0.8 of gestational age. Trigeminal SEP were evoked prior to, 4 and 24 h after each injection and at 0.8 of gestational age before brains were histologically processed. Somatosensory-evoked potentials were already detectable at 0.7 of gestation age. The early and late responses N20 and N200 were the only reproducible peaks over the entire study period. With advancing gestational age, SEP latencies decreased but amplitudes remained unchanged. Acutely, betamethasone did not affect SEP latencies and amplitudes 4 and 24 h following administration. Chronically, betamethasone delayed developmental decrease in the N200 but not N20 latency by 2 weeks without affecting amplitudes. In parallel, betamethasone decreased subcortical white matter myelination but did not affect network formation and synaptic density in the somatosensory cortex. Somatosensory stimuli are already processed by the foetal cerebral cortex at the beginning of the third trimester. Subsequent developmental decrease in SEP latencies suggests ongoing maturation of afferent sensory transmission. Antenatal glucocorticoids affect structural and functional development of the somatosensory system with specific effects at subcortical level. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Cold-evoked potentials - Ready for clinical use?

PubMed

Hüllemann, P; Nerdal, A; Binder, A; Helfert, S; Reimer, M; Baron, R

2016-11-01

Cold-evoked potentials (CEPs) are known to assess the integrity of A-delta fibres and the spinothalamic tract. Nevertheless, the clinical value was not investigated previously. The aim of this study was to measure CEPs in 16 healthy subjects from the face, hand and foot sole and to investigate whether CEPs reliably detect A-delta fibre abnormalities. Swift cold stimuli were applied to the skin with a commercially available thermode, which cooled down from 30 to 25 °C in approximately 0.5 s. CEP latencies (N1, N2 and P2) and amplitudes (N1, N2/P2) were recorded with EEG. Reversible A-fibre function loss was induced by applying a selective A-fibre block at the superficial radial nerve. In all 16 subjects CEPs could be recorded from all locations; N2, P2 mean latencies were 276.4 ± 38.9 and 389.8 ± 52.5 (face), 318.6 ± 31.6 ms and 477.7 ± 43.6 (hand), and 627.6 ± 84.4 and 774.2 ± 94.0 (foot sole). N2/P2 amplitudes were 10.7 ± 4.1, 11.3 ± 4.1 and 7.5 ± 4.1 μV. During A-fibre block no CEPs were detectable in the grand average, which restored 10 min after block removal. CEPs were reliably recorded in healthy subjects at the hand, face and foot. Experimentally induced reversible A-delta fibre function loss was detected by CEPs. Functional recovery was assessed as well. This study is basis for further CEP evaluation studies and might be the first step for implementing CEPs in clinical routine for the early diagnosis of small-fibre disease. WHAT DOES THIS STUDY ADD?: Cold-evoked potentials are capable of reliably measuring A-delta fibre integrity, loss of function and functional recovery in healthy subjects, which is an essential prerequisite for diagnostic use in patients with small-fibre disease. © 2016 European Pain Federation - EFIC®.

Matched Filtering of Visual Evoked Potentials to Detect Acceleration (+Gz) Induced Blackout

DTIC Science & Technology

1985-01-03

FILTERING OF VISUAL EVOKED POTENTIALS rO DETECT ACCELERATION ( + Gz) INDUCED BLACKOUT John Q. Nelson, Leonid Hrebien and Joseph P. Cammarota Aircraft...8217: , r .,.V -. 1-». .v. IE •> _"->.-"*« A^V :j% _"«;_"V X~«. _~»^"V.i.~» iuTtuTii i."»..-^. .-*._> r /; NOTICES REPORT NUMBERING SYSTEM - The...Potentials to Detect Acceleration (+G2) Induced Blackout 12 PERSONAL AUTHOR(S) John G. Nelson, Leonid Hrebien, Joseph P. Cammarota 13* TYPE OF REPORT

Irregular Speech Rate Dissociates Auditory Cortical Entrainment, Evoked Responses, and Frontal Alpha

PubMed Central

Kayser, Stephanie J.; Ince, Robin A.A.; Gross, Joachim

2015-01-01

The entrainment of slow rhythmic auditory cortical activity to the temporal regularities in speech is considered to be a central mechanism underlying auditory perception. Previous work has shown that entrainment is reduced when the quality of the acoustic input is degraded, but has also linked rhythmic activity at similar time scales to the encoding of temporal expectations. To understand these bottom-up and top-down contributions to rhythmic entrainment, we manipulated the temporal predictive structure of speech by parametrically altering the distribution of pauses between syllables or words, thereby rendering the local speech rate irregular while preserving intelligibility and the envelope fluctuations of the acoustic signal. Recording EEG activity in human participants, we found that this manipulation did not alter neural processes reflecting the encoding of individual sound transients, such as evoked potentials. However, the manipulation significantly reduced the fidelity of auditory delta (but not theta) band entrainment to the speech envelope. It also reduced left frontal alpha power and this alpha reduction was predictive of the reduced delta entrainment across participants. Our results show that rhythmic auditory entrainment in delta and theta bands reflect functionally distinct processes. Furthermore, they reveal that delta entrainment is under top-down control and likely reflects prefrontal processes that are sensitive to acoustical regularities rather than the bottom-up encoding of acoustic features. SIGNIFICANCE STATEMENT The entrainment of rhythmic auditory cortical activity to the speech envelope is considered to be critical for hearing. Previous work has proposed divergent views in which entrainment reflects either early evoked responses related to sound encoding or high-level processes related to expectation or cognitive selection. Using a manipulation of speech rate, we dissociated auditory entrainment at different time scales. Specifically, our

The division of attention and the human auditory evoked potential

NASA Technical Reports Server (NTRS)

Hink, R. F.; Van Voorhis, S. T.; Hillyard, S. A.; Smith, T. S.

1977-01-01

The sensitivity of the scalp-recorded, auditory evoked potential to selective attention was examined while subjects responded to stimuli presented to one ear (focused attention) and to both ears (divided attention). The amplitude of the N1 component was found to be largest to stimuli in the ear upon which attention was to be focused, smallest to stimuli in the ear to be ignored, and intermediate to stimuli in both ears when attention was divided. The results are interpreted as supporting a capacity model of attention.

Visual evoked potentials through night vision goggles.

PubMed

Rabin, J

1994-04-01

Night vision goggles (NVG's) have widespread use in military and civilian environments. NVG's amplify ambient illumination making performance possible when there is insufficient illumination for normal vision. While visual performance through NVG's is commonly assessed by measuring threshold functions such as visual acuity, few attempts have been made to assess vision through NVG's at suprathreshold levels of stimulation. Such information would be useful to better understand vision through NVG's across a range of stimulus conditions. In this study visual evoked potentials (VEP's) were used to evaluate vision through NVG's across a range of stimulus contrasts. The amplitude and latency of the VEP varied linearly with log contrast. A comparison of VEP's recorded with and without NVG's was used to estimate contrast attenuation through the device. VEP's offer an objective, electrophysiological tool to assess visual performance through NVG's at both threshold and suprathreshold levels of visual stimulation.

Short-Latency Median-Nerve Somatosensory-Evoked Potentials and Induced Gamma-Oscillations in Humans

ERIC Educational Resources Information Center

Fukuda, Miho; Nishida, Masaaki; Juhasz, Csaba; Muzik, Otto; Sood, Sandeep; Chugani, Harry T.; Asano, Eishi

2008-01-01

Recent studies have suggested that cortical gamma-oscillations are tightly linked with various forms of physiological activity. In the present study, the dynamic changes of intracranially recorded median-nerve somatosensory-evoked potentials (SEPs) and somatosensory-induced gamma-oscillations were animated on a three-dimensional MR image, and the…

The cortical spatiotemporal correlate of otolith stimulation: Vestibular evoked potentials by body translations.

PubMed

Ertl, M; Moser, M; Boegle, R; Conrad, J; Zu Eulenburg, P; Dieterich, M

2017-07-15

The vestibular organ senses linear and rotational acceleration of the head during active and passive motion. These signals are necessary for bipedal locomotion, navigation, the coordination of eye and head movements in 3D space. The temporal dynamics of vestibular processing in cortical structures have hardly been studied in humans, let alone with natural stimulation. The aim was to investigate the cortical vestibular network related to natural otolith stimulation using a hexapod motion platform. We conducted two experiments, 1. to estimate the sources of the vestibular evoked potentials (VestEPs) by means of distributed source localization (n=49), and 2. to reveal modulations of the VestEPs through the underlying acceleration intensity (n=24). For both experiments subjects were accelerated along the main axis (left/right, up/down, fore/aft) while the EEG was recorded. We were able to identify five VestEPs (P1, N1, P2, N2, P3) with latencies between 38 and 461 ms as well as an evoked beta-band response peaking with a latency of 68 ms in all subjects and for all acceleration directions. Source localization gave the cingulate sulcus visual (CSv) area and the opercular-insular region as the main origin of the evoked potentials. No lateralization effects due to handedness could be observed. In the second experiment, area CSv was shown to be integral in the processing of acceleration intensities as sensed by the otolith organs, hinting at its potential role in ego-motion detection. These robust VestEPs could be used to investigate the mechanisms of inter-regional interaction in the natural context of vestibular processing and multisensory integration. Copyright © 2017 Elsevier Inc. All rights reserved.

Comparison of Motor-Evoked Potentials Versus Somatosensory-Evoked Potentials as Early Indicators of Neural Compromise in Rat Model of Spinal Cord Compression.

PubMed

Morris, Susan H; Howard, Jason J; El-Hawary, Ron

2017-03-15

Randomized controlled study comparing the efficacy of intraoperative somatosensory-evoked potentials (SSEPs) versus transcranial motor-evoked potentials (TcMEPs) as early indicators of neural compromise and predictors of postoperative function in a rat model of spinal cord compression. To compare the relative efficacy of SSEPs and TcMEPs to detect spinal cord compromise and predict postoperative functional deficit after spinal cord compression. There is controversy regarding the efficacy of SSEPs versus TcMEPs to detect intraoperative spinal cord compromise and predict functional outcomes. Previous trials provide some guidance as to the role of each modality in spinal cord monitoring but randomized controlled trials, which are not feasible in humans, are lacking. Twenty-four adult male Wistar rats were evenly divided into three experimental groups and one control group. The experimental groups were determined according to the length of time that 100% TcMEP signal loss was maintained: 0, 5, or 15 minutes. All animals had standardized preoperative functional testing. Spinal cord compromise was initiated utilizing a validated protocol, which involved compression via a balloon catheter introduced into the thoracic sublaminar space. Both SSEPs and TcMEPs were recorded during cord compression for each experimental group. Functional behavioral testing using two validated methods (tilt and modified Tarlov) was repeated 24 hours after termination of spinal cord compression. Post hoc, animals were redistributed into two functional subgroups, noncompromised and compromised, for statistical analysis. TcMEPs consistently detected spinal cord compromise either in advance of or at the same time as SSEPs; however, the delay in SSEP response was not significant for cases when compromised postoperative function resulted. Both SSEP and TcMEP amplitude recovery correlated well with postoperative functional scores. TcMEPs are more sensitive to spinal cord compromise than SSEPs, but the

WITHIN-SESSION CHANGES IN PEAK N160 AMPLITUDE OF FLASH EVOKED POTENTIALS IN RATS

EPA Science Inventory

The negative peak occurring approximately 160 msec after stimulation (peak N 160) flash evoked potentials (FEPS) of rats changes with repeated testing. abituation, sensitization, and arousal have all been invoked to explain these changes, but few studies have directly tested thes...

The Direct Detection of a Single Evoked Action Potential with Magnetic Resonance Spectroscopy in Lumbricus Terrestris

PubMed Central

Poplawsky, Alexander J.; Dingledine, Raymond

2011-01-01

Functional MRI (fMRI) indirectly measures neural activity by detecting the signal change associated with the hemodynamic response following brain activation. In order to alleviate the temporal and spatial specificity problems associated with fMRI, a number of attempts have been made to detect neural magnetic fields (NMFs) with MRI directly, but have thus far provided conflicting results. In the present study, we used magnetic resonance to detect axonal NMFs in the median giant fiber of the earthworm, Lumbricus terrestris, by examining the free-induction decay (FID) with a sampling interval of 0.32 ms. The earthworm nerve cords were isolated from the vasculature and stimulated at the threshold of action potential generation. FIDs were acquired shortly after the stimulation and simultaneous field potential recordings identified the presence or absence of single evoked action potentials. FIDs acquired when the stimulus did not evoke an action potential were summed as background. The phase of the background-subtracted FID exhibited a systematic change, with a peak phase difference of [-1.2 ± 0.3] ×10-5 radians occurring at a time corresponding to the timing of the action potential. In addition, we calculated the possible changes in the FID magnitude and phase due to a simulated action potential using a volume conductor model. The measured phase difference matched the theoretical prediction well in both amplitude and temporal characteristics. This study provides the first evidence for the direct detection of a magnetic field from an evoked action potential using magnetic resonance. PMID:21728204

Visual evoked potentials in the horse.

PubMed

Ström, L; Ekesten, B

2016-06-21

Electrical potentials generated in the central nervous system in response to brief visual stimuli, flash visual evoked potentials (FVEPs), can be recorded non-invasively over the occipital cortex. FVEPs are used clinically in human medicine and also experimentally in a number of animal species, but the method has not yet been evaluated in the horse. The method would potentially allow the ophthalmologist and equine clinician to evaluate visual impairment caused by disorders affecting post-retinal visual pathways. The aim was to establish a method for recording of FVEPs in horses in a clinical setting and to evaluate the waveform morphology in the normal horse. Ten horses were sedated with a continuous detomidine infusion. Responses were recorded from electrodes placed on the scalp. Several positions were evaluated to determine suitable electrode placement. Flash electroretinograms (FERGs) were recorded simultaneously. To evaluate potential contamination of the FVEP from retinal potentials, a retrobulbar nerve block was performed in two horses and transection of the optic nerve was performed in one horse as a terminal procedure. A series of positive (P) and negative (N) peaks in response to light stimuli was recorded in all horses. Reproducible wavelets with mean times-to-peaks of 26 (N1), 55 (P2), 141 (N2) and 216 ms (P4) were seen in all horses in all recordings. Reproducible results were obtained when the active electrode was placed in the midline rostral to the nuchal crest. Recording at lateral positions gave more variable results, possibly due to ear muscle artifacts. Averaging ≥100 responses reduced the impact of noise and artifacts. FVEPs were reproducible in the same horse during the same recording session and between sessions, but were more variable between horses. Retrobulbar nerve block caused a transient loss of the VEP whereas transection of the optic nerve caused an irreversible loss. We describe the waveform of the equine FVEP and our results show

Objective Assessment of Spectral Ripple Discrimination in Cochlear Implant Listeners Using Cortical Evoked Responses to an Oddball Paradigm

PubMed Central

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B.

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2 = 0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users. PMID:24599314

Objective assessment of spectral ripple discrimination in cochlear implant listeners using cortical evoked responses to an oddball paradigm.

PubMed

Lopez Valdes, Alejandro; Mc Laughlin, Myles; Viani, Laura; Walshe, Peter; Smith, Jaclyn; Zeng, Fan-Gang; Reilly, Richard B

2014-01-01

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2=0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users.

Evoked potential correlates of selective attention with multi-channel auditory inputs

NASA Technical Reports Server (NTRS)

Schwent, V. L.; Hillyard, S. A.

1975-01-01

Ten subjects were presented with random, rapid sequences of four auditory tones which were separated in pitch and apparent spatial position. The N1 component of the auditory vertex evoked potential (EP) measured relative to a baseline was observed to increase with attention. It was concluded that the N1 enhancement reflects a finely tuned selective attention to one stimulus channel among several concurrent, competing channels. This EP enhancement probably increases with increased information load on the subject.

Control of humanoid robot via motion-onset visual evoked potentials

PubMed Central

Li, Wei; Li, Mengfan; Zhao, Jing

2015-01-01

This paper investigates controlling humanoid robot behavior via motion-onset specific N200 potentials. In this study, N200 potentials are induced by moving a blue bar through robot images intuitively representing robot behaviors to be controlled with mind. We present the individual impact of each subject on N200 potentials and discuss how to deal with individuality to obtain a high accuracy. The study results document the off-line average accuracy of 93% for hitting targets across over five subjects, so we use this major component of the motion-onset visual evoked potential (mVEP) to code people's mental activities and to perform two types of on-line operation tasks: navigating a humanoid robot in an office environment with an obstacle and picking-up an object. We discuss the factors that affect the on-line control success rate and the total time for completing an on-line operation task. PMID:25620918

[The modified method registration of kinesthetic evoked potentials and its application for research of proprioceptive sensitivity disorders at spondylogenic cervical myelopathy].

PubMed

Gordeev, S A; Voronin, S G

2016-01-01

To analyze the efficacy of modified (passive radiocarpal articulation flexion/extension) and «standard» (passive radiocarpal articulation flexion) methods of kinesthetic evoked potentials for proprioceptive sensitivity assessment in healthy subjects and patients with spondylotic cervical myelopathy. The study included 14 healthy subjects (4 women and 10 men, mean age 54.1±10.5 years) and 8 patients (2 women and 6 men, mean age 55.8±10.9 years) with spondylotic cervical myelopathy. Muscle-joint sensation was examined during the clinical study. A modified method of kinesthetic evoked potentials was developed. This method differed from the "standard" one by the organization of a cycle including several passive movements,where each new movement differed from the preceding one by the direction. The modified method of kinesthetic evoked potentials ensures more reliable kinesthetic sensitivity assessment due to movement variability. Asignificant increaseof the latent periods of the early components of the response was found in patients compared to healthy subjects. The modified method of kinesthetic evoked potentials can be used for objective diagnosis of proprioceptive sensitivity disorders in patients with spondylotic cervical myelopathy.

Adaptive regularization network based neural modeling paradigm for nonlinear adaptive estimation of cerebral evoked potentials.

PubMed

Zhang, Jian-Hua; Böhme, Johann F

2007-11-01

In this paper we report an adaptive regularization network (ARN) approach to realizing fast blind separation of cerebral evoked potentials (EPs) from background electroencephalogram (EEG) activity with no need to make any explicit assumption on the statistical (or deterministic) signal model. The ARNs are proposed to construct nonlinear EEG and EP signal models. A novel adaptive regularization training (ART) algorithm is proposed to improve the generalization performance of the ARN. Two adaptive neural modeling methods based on the ARN are developed and their implementation and performance analysis are also presented. The computer experiments using simulated and measured visual evoked potential (VEP) data have shown that the proposed ARN modeling paradigm yields computationally efficient and more accurate VEP signal estimation owing to its intrinsic model-free and nonlinear processing characteristics.

Effects of propofol, sevoflurane, remifentanil, and (S)-ketamine in subanesthetic concentrations on visceral and somatosensory pain-evoked potentials.

PubMed

Untergehrer, Gisela; Jordan, Denis; Eyl, Sebastian; Schneider, Gerhard

2013-02-01

Although electroencephalographic parameters and auditory evoked potentials (AEP) reflect the hypnotic component of anesthesia, there is currently no specific and mechanism-based monitoring tool for anesthesia-induced blockade of nociceptive inputs. The aim of this study was to assess visceral pain-evoked potentials (VPEP) and contact heat-evoked potentials (CHEP) as electroencephalographic indicators of drug-induced changes of visceral and somatosensory pain. Additionally, AEP and electroencephalographic permutation entropy were used to evaluate sedative components of the applied drugs. In a study enrolling 60 volunteers, VPEP, CHEP (amplitude N2-P1), and AEP (latency Nb, amplitude Pa-Nb) were recorded without drug application and at two subanesthetic concentration levels of propofol, sevoflurane, remifentanil, or (s)-ketamine. Drug-induced changes of evoked potentials were analyzed. VPEP were generated by electric stimuli using bipolar electrodes positioned in the distal esophagus. For CHEP, heat pulses were given to the medial aspect of the right forearm using a CHEP stimulator. In addition to AEP, electroencephalographic permutation entropy was used to indicate level of sedation. With increasing concentrations of propofol, sevoflurane, remifentanil, and (s)-ketamine, VPEP and CHEP N2-P1 amplitudes decreased. AEP and electroencephalographic permutation entropy showed neither clinically relevant nor statistically significant suppression of cortical activity during drug application. Decreasing VPEP and CHEP amplitudes under subanesthetic concentrations of propofol, sevoflurane, remifentanil, and (s)-ketamine indicate suppressive drug effects. These effects seem to be specific for analgesia.

Normative data for Aδ contact heat evoked potentials in adult population: a multicenter study.

PubMed

Granovsky, Yelena; Anand, Praveen; Nakae, Aya; Nascimento, Osvaldo; Smith, Benn; Sprecher, Elliot; Valls-Solé, Josep

2016-05-01

There has been a significant increase over recent years in the use of contact heat evoked potentials (CHEPs) for the evaluation of small nerve fiber function. Measuring CHEP amplitude and latency has clinical utility for the diagnosis and assessment of conditions with neuropathic pain. This international multicenter study aimed to provide reference values for CHEPs to stimuli at 5 commonly examined body sites. Contact heat evoked potentials were recorded from 226 subjects (114 females), distributed per age decade between 20 and 79 years. Temperature stimuli were delivered by a thermode (32°C-51°C at a rate of 70°C/s). In phase I of the study, we investigated side-to-side differences and reported the maximum normal side-to-side difference in Aδ CHEP peak latency and amplitude for leg, forearm, and face. In phase II, we obtained normative data for 3 CHEP parameters (N2P2 amplitude, N2 latency, and P2 latency), stratified for gender and age decades from face, upper and lower limbs, and overlying cervical and lumbar spine. In general, larger CHEP amplitudes were associated with higher evoked pain scores. Females had CHEPs of larger amplitude and shorter latency than males. This substantive data set of normative values will facilitate the clinical use of CHEPs as a rapid, noninvasive, and objective technique for the assessment of patients presenting with neuropathic pain.

Accuracy of measurement in electrically evoked compound action potentials.

PubMed

Hey, Matthias; Müller-Deile, Joachim

2015-01-15

Electrically evoked compound action potentials (ECAP) in cochlear implant (CI) patients are characterized by the amplitude of the N1P1 complex. The measurement of evoked potentials yields a combination of the measured signal with various noise components but for ECAP procedures performed in the clinical routine, only the averaged curve is accessible. To date no detailed analysis of error dimension has been published. The aim of this study was to determine the error of the N1P1 amplitude and to determine the factors that impact the outcome. Measurements were performed on 32 CI patients with either CI24RE (CA) or CI512 implants using the Software Custom Sound EP (Cochlear). N1P1 error approximation of non-averaged raw data consisting of recorded single-sweeps was compared to methods of error approximation based on mean curves. The error approximation of the N1P1 amplitude using averaged data showed comparable results to single-point error estimation. The error of the N1P1 amplitude depends on the number of averaging steps and amplification; in contrast, the error of the N1P1 amplitude is not dependent on the stimulus intensity. Single-point error showed smaller N1P1 error and better coincidence with 1/√(N) function (N is the number of measured sweeps) compared to the known maximum-minimum criterion. Evaluation of N1P1 amplitude should be accompanied by indication of its error. The retrospective approximation of this measurement error from the averaged data available in clinically used software is possible and best done utilizing the D-trace in forward masking artefact reduction mode (no stimulation applied and recording contains only the switch-on-artefact). Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of neck flexion on somatosensory and motor evoked potentials in Hirayama disease.

PubMed

Abraham, A; Gotkine, M; Drory, V E; Blumen, S C

2013-11-15

Hirayama disease (HD) is a rare motor disorder mainly affecting young men, characterized by atrophy and weakness of forearm and hand muscles corresponding to a C7-T1 myotome distribution. The weakness is usually unilateral or asymmetric and progression usually stops within several years. The etiology of HD is not well understood. One hypothesis, mainly based on MRI findings, is that the weakness is a consequence of cervical flexion myelopathy. The aim of this study was to explore the function of corticospinal and ascending somatosensory pathways during neck flexion using evoked responses. 15 men with HD and 7 age-matched control male subjects underwent somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) studies with the neck in neutral position and fully flexed. SSEP studies included electrical stimulation of median and ulnar nerves at the wrist, and tibial nerve at the ankle with recording over the ipsilateral Erb's point, cervical spine, and contralateral sensory cortex. MEP recordings were obtained by magnetic stimulation of the motor cortex and the cervical lower spinal roots; the evoked responses were recorded from the contralateral thenar and abductor hallucis muscles. MEP recordings demonstrated significant lower amplitudes, and slightly prolonged latencies in HD patients on cervical stimulation, compared to control subjects. During neck flexion, MEP studies also demonstrated a statistically significant drop in mean upper limb amplitude on cervical stimulation in HD patients, as well as in control subjects, although to a lesser degree. In contrast, no significant differences were found in SSEP studies in HD patients compared to control subjects, or between neutral and flexed position in these groups. The study shows a negative effect of cervical flexion on MEP amplitudes in HD patients as well as in control subjects, requiring more studies to investigate its significance. Neck flexion did not have an influence on any SSEP parameters in

The impact of emotion on respiratory-related evoked potentials

PubMed Central

von Leupoldt, Andreas; Vovk, Andrea; Bradley, Margaret M.; Keil, Andreas; Lang, Peter J.; Davenport, Paul W.

2013-01-01

Emotion influences the perception of respiratory sensations, although the specific mechanism underlying this modulation is not yet clear. We examined the impact of viewing pleasant, neutral, and unpleasant affective pictures on the respiratory-related evoked potential (RREP) elicited by a short inspiratory occlusion in healthy volunteers. Reduced P3 amplitude of the RREP was found for respiratory probes presented when viewing pleasant or unpleasant series, when compared to those presented during the neutral series. Earlier RREP components, such as Nf, P1, N1, and P2, showed no modulation by emotion. The results suggest that emotion impacts the perception of respiratory sensations by reducing the attentional resources available for processing afferent respiratory sensory signals. PMID:20070570

Vestibular-dependent inter-stimulus interval effects on sound evoked potentials of central origin.

PubMed

Todd, N P M; Govender, S; Colebatch, J G

2016-11-01

Todd et al. (2014ab) have recently demonstrated the presence of vestibular-dependent contributions to auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs), including a particular deflection labeled as an N42/P52 prior to the long-latency AEPs N1 and P2. In this paper we report the results of an experiment to determine the effect of inter-stimulus interval (ISI) and regularity on potentials recorded above and below VEMP threshold. Five healthy, right-handed subjects were recruited and evoked potentials were recorded to binaurally presented sound stimulation, above and below vestibular threshold, at seven stimulus rates with ISIs of 212, 300, 424, 600, 848, 1200 and 1696 ms. The inner five intervals, i.e. 300, 424, 600, 848, 1200 ms, were presented twice in both regular and irregular conditions. ANOVA on the global field power (GFP) were conducted for each of four waves, N42, P52, N1 and P2 with factors of intensity, ISI and regularity. Both N42 and P52 waves showed significant ANOVA effects of intensity but no other main effects or interactions. In contrast both N1 and P2 showed additional effects of ISI, as well as intensity, and evidence of non-linear interactions between ISI and intensity. A source analysis was carried out consistent with prior work suggesting that when above vestibular threshold, in addition to bilateral superior temporal cortex, ocular, cerebellar and cingulate sources are recruited. Further statistical analysis of the source currents indicated that the origin of the interactions with intensity may be the ISI sensitivity of the vestibular-dependent sources. This in turn may reflect a specific vestibular preference for stimulus rates associated with locomotion, i.e. rates close to 2 Hz, or ISIs close to 500 ms, where saccular afferents show increased gain and the corresponding reflexes are most sensitive. Copyright © 2016 The Authors. Published by

Auditory- and visual-evoked potentials in Mexican infants are not affected by maternal supplementation with 400 mg/d docosahexaenoic acid in the second half of pregnancy.

PubMed

Stein, Aryeh D; Wang, Meng; Rivera, Juan A; Martorell, Reynaldo; Ramakrishnan, Usha

2012-08-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18-22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26-0.43; all P < 0.001) and left-right visual-evoked potentials were strongly correlated (range, 0.79-0.94; all P < 0.001) within any assessment. Correlations across visits were modest to moderate (range, 0.09-0.38; all P < 0.01). The offspring of DHA-supplemented women did not differ from those of control women with respect to any outcome measure (all comparisons P > 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo.

Interaction of emitted sonar pulses and simulated echoes in a false killer whale: an evoked-potential study.

PubMed

Supin, Alexander Ya; Nachtigall, Paul E; Breese, Marlee

2011-09-01

Auditory evoked potentials (AEP) were recorded during echolocation in a false killer whale Pseudorca crassidens. An electronically synthesized and played-back (simulated) echo was triggered by an emitted biosonar pulse, and its intensity was proportional to that of the emitted click. The delay and transfer factor of the echo relative to the emitted click was controlled by the operator. The echo delay varied from 2 to 16 ms (by two-fold steps), and the transfer factor varied within ranges from -45 to -30 dB at the 2-ms delay to -60 to -45 dB at the 16-ms delay. Echo-related AEPs featured amplitude dependence both on echo delay at a constant transfer factor (the longer the delay, the higher amplitude) and on echo transfer factor at a constant delay (the higher transfer factor, the higher amplitude). Conjunctional variation of the echo transfer factor and delay kept the AEP amplitude constant when the delay to transfer factor trade was from -7.1 to -8.4 dB per delay doubling. The results confirm the hypothesis that partial forward masking of the echoes by the preceding emitted sonar pulses serves as a time-varying automatic gain control in the auditory system of echolocating odontocetes. © 2011 Acoustical Society of America

Auditory evoked potentials in the auditory system of a beluga whale Delphinapterus leucas to prolonged sound stimuli.

PubMed

Popov, Vladimir V; Sysueva, Evgenia V; Nechaev, Dmitry I; Rozhnov, Vyatcheslav V; Supin, Alexander Ya

2016-03-01

The effects of prolonged (up to 1500 s) sound stimuli (tone pip trains) on evoked potentials (the rate following response, RFR) were investigated in a beluga whale. The stimuli (rhythmic tone pips) were of frequencies of 45, 64, and 90 kHz at levels from 20 to 60 dB above threshold. Two experimental protocols were used: short- and long-duration. For the short-duration protocol, the stimuli were 500-ms-long pip trains that repeated at a rate of 0.4 trains/s. For the long-duration protocol, the stimuli were continuous pip successions lasting up to 1500 s. The RFR amplitude gradually decreased by three to seven times from 10 ms to 1500 s of stimulation. Decrease of response amplitude during stimulation was approximately proportional to initial (at the start of stimulation) response amplitude. Therefore, even for low stimulus level (down to 20 dB above the baseline threshold) the response was never suppressed completely. The RFR amplitude decay that occurred during stimulation could be satisfactorily approximated by a combination of two exponents with time constants of 30-80 ms and 3.1-17.6 s. The role of adaptation in the described effects and the impact of noise on the acoustic orientation of odontocetes are discussed.

Interhemispheric Asymmetries in Visual Evoked Potential Amplitude

DTIC Science & Technology

1980-06-12

Layne, 1965) and of patients with Korsakoff’s syndrome (Malerstein and Callaway, 1969) . In the schizophrenics, the high variability is related to poor...communication. Malerstein, A. J., Callaway, E. Two-tone average evoked response in Korsakoff patients. J. Psychiatr. Res. 6: 253-260, 1969. Marsh, G

Acoustic Events and “Optophonic” Cochlear Responses Induced by Pulsed Near-Infrared LASER

PubMed Central

Maier, Hannes; Richter, Claus-Peter; Kral, Andrej

2012-01-01

Optical stimulation of neural tissue within the cochlea was described as a possible alternative to electrical stimulation. Most optical stimulation was performed with pulsed lasers operating with near-infrared (NIR) light and in thermal confinement. Under these conditions, the coexistence of laser-induced optoacoustic stimulation of the cochlea (“optophony”) has not been analyzed yet. This study demonstrates that pulsed 1850-nm laser light used for neural stimulation also results in sound pressure levels up to 62 dB peak-to-peak equivalent sound pressure level (SPL) in air. The sound field was confined to a small volume along the laser beam. In dry nitrogen, laser-induced acoustic events disappeared. Hydrophone measurements demonstrated pressure waves for laser fibers immersed in water. In hearing rats, laser-evoked signals were recorded from the cochlea without targeting neural tissue. The signals showed a two-domain response differing in amplitude and latency functions, as well as sensitivity to white-noise masking. The first component had characteristics of a cochlear microphonic potential, and the second component was characteristic for a compound action potential. The present data demonstrate that laser-evoked acoustic events can stimulate a hearing cochlea. Whenever optical stimulation is used, care must be taken to distinguish between such “optophony” and the true optoneural response. PMID:21278011

Multifocal Visual Evoked Potential in Eyes With Temporal Hemianopia From Chiasmal Compression: Correlation With Standard Automated Perimetry and OCT Findings.

PubMed

Sousa, Rafael M; Oyamada, Maria K; Cunha, Leonardo P; Monteiro, Mário L R

2017-09-01

To verify whether multifocal visual evoked potential (mfVEP) can differentiate eyes with temporal hemianopia due to chiasmal compression from healthy controls. To assess the relationship between mfVEP, standard automated perimetry (SAP), and Fourier domain-optical coherence tomography (FD-OCT) macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements. Twenty-seven eyes with permanent temporal visual field (VF) defects from chiasmal compression on SAP and 43 eyes of healthy controls were submitted to mfVEP and FD-OCT scanning. Multifocal visual evoked potential was elicited using a stimulus pattern of 60 sectors and the responses were averaged for the four quadrants and two hemifields. Optical coherence tomography macular measurements were averaged in quadrants and halves, while peripapillary RNFL thickness was averaged in four sectors around the disc. Visual field loss was estimated in four quadrants and each half of the 24-2 strategy test points. Multifocal visual evoked potential measurements in the two groups were compared using generalized estimated equations, and the correlations between mfVEP, VF, and OCT findings were quantified. Multifocal visual evoked potential-measured temporal P1 and N2 amplitudes were significantly smaller in patients than in controls. No significant difference in amplitude was observed for nasal parameters. A significant correlation was found between mfVEP amplitudes and temporal VF loss, and between mfVEP amplitudes and the corresponding OCT-measured macular and RNFL thickness parameters. Multifocal visual evoked potential amplitude parameters were able to differentiate eyes with temporal hemianopia from controls and were significantly correlated with VF and OCT findings, suggesting mfVEP is a useful tool for the detection of visual abnormalities in patients with chiasmal compression.

Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories.

PubMed

Karns, Christina M; Isbell, Elif; Giuliano, Ryan J; Neville, Helen J

2015-06-01

Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs) across five age groups: 3-5 years; 10 years; 13 years; 16 years; and young adults. Using a naturalistic dichotic listening paradigm, we characterized the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories

PubMed Central

Karns, Christina M.; Isbell, Elif; Giuliano, Ryan J.; Neville, Helen J.

2015-01-01

Auditory selective attention is a critical skill for goal-directed behavior, especially where noisy distractions may impede focusing attention. To better understand the developmental trajectory of auditory spatial selective attention in an acoustically complex environment, in the current study we measured auditory event-related potentials (ERPs) in human children across five age groups: 3–5 years; 10 years; 13 years; 16 years; and young adults using a naturalistic dichotic listening paradigm, characterizing the ERP morphology for nonlinguistic and linguistic auditory probes embedded in attended and unattended stories. We documented robust maturational changes in auditory evoked potentials that were specific to the types of probes. Furthermore, we found a remarkable interplay between age and attention-modulation of auditory evoked potentials in terms of morphology and latency from the early years of childhood through young adulthood. The results are consistent with the view that attention can operate across age groups by modulating the amplitude of maturing auditory early-latency evoked potentials or by invoking later endogenous attention processes. Development of these processes is not uniform for probes with different acoustic properties within our acoustically dense speech-based dichotic listening task. In light of the developmental differences we demonstrate, researchers conducting future attention studies of children and adolescents should be wary of combining analyses across diverse ages. PMID:26002721

Innovative neurophysiological methods in itch research: long-latency evoked potentials after electrical and thermal stimulation in patients with atopic dermatitis.

PubMed

Yudina, Marina M; Toropina, Galina G; Lvov, Andrey; Gieler, Uwe

2011-10-01

The aim of this study was to examine the findings of innovative neurophysiological methods of itch research. Short-latency and pain-related somatosensory-evoked potentials after electrical stimulation, as well as long-latency evoked potentials after thermal stimulation were studied in 38 patients with atopic dermatitis (AD) and 26 healthy volunteers. Quantitative Sensory Testing of thermal perception was performed in 22 patients with AD from the main AD group and in 15 healthy volunteers. Brain hyperactivity to electrical stimuli, delayed thermal-evoked potentials and elevated thermal thresholds were revealed in patients with AD compared with healthy controls. The data indicate small nerve fibre dysfunction in patients with AD, which may contribute to the pathogenesis of AD and chronic itch. The study demonstrates objective approaches to assess the function of small nerve fibres in patients with chronic itch.

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

PubMed

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

2013-01-01

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

Maximally reliable spatial filtering of steady state visual evoked potentials.

PubMed

Dmochowski, Jacek P; Greaves, Alex S; Norcia, Anthony M

2015-04-01

Due to their high signal-to-noise ratio (SNR) and robustness to artifacts, steady state visual evoked potentials (SSVEPs) are a popular technique for studying neural processing in the human visual system. SSVEPs are conventionally analyzed at individual electrodes or linear combinations of electrodes which maximize some variant of the SNR. Here we exploit the fundamental assumption of evoked responses--reproducibility across trials--to develop a technique that extracts a small number of high SNR, maximally reliable SSVEP components. This novel spatial filtering method operates on an array of Fourier coefficients and projects the data into a low-dimensional space in which the trial-to-trial spectral covariance is maximized. When applied to two sample data sets, the resulting technique recovers physiologically plausible components (i.e., the recovered topographies match the lead fields of the underlying sources) while drastically reducing the dimensionality of the data (i.e., more than 90% of the trial-to-trial reliability is captured in the first four components). Moreover, the proposed technique achieves a higher SNR than that of the single-best electrode or the Principal Components. We provide a freely-available MATLAB implementation of the proposed technique, herein termed "Reliable Components Analysis". Copyright © 2015 Elsevier Inc. All rights reserved.

Automatic Parametrization of Somatosensory Evoked Potentials With Chirp Modeling.

PubMed

Vayrynen, Eero; Noponen, Kai; Vipin, Ashwati; Thow, X Y; Al-Nashash, Hasan; Kortelainen, Jukka; All, Angelo

2016-09-01

In this paper, an approach using polynomial phase chirp signals to model somatosensory evoked potentials (SEPs) is proposed. SEP waveforms are assumed as impulses undergoing group velocity dispersion while propagating along a multipath neural connection. Mathematical analysis of pulse dispersion resulting in chirp signals is performed. An automatic parameterization of SEPs is proposed using chirp models. A Particle Swarm Optimization algorithm is used to optimize the model parameters. Features describing the latencies and amplitudes of SEPs are automatically derived. A rat model is then used to evaluate the automatic parameterization of SEPs in two experimental cases, i.e., anesthesia level and spinal cord injury (SCI). Experimental results show that chirp-based model parameters and the derived SEP features are significant in describing both anesthesia level and SCI changes. The proposed automatic optimization based approach for extracting chirp parameters offers potential for detailed SEP analysis in future studies. The method implementation in Matlab technical computing language is provided online.

Rhesus macaque model of chronic opiate dependence and neuro-AIDS: longitudinal assessment of auditory brainstem responses and visual evoked potentials

PubMed Central

Riazi, Mariam; Marcario, Joanne K; Samson, Frank K.; Kenjale, Himanshu; Adany, Istvan; Staggs, Vincent; Ledford, Emily; Marquis, Janet; Narayan, Opendra; Cheney, Paul D.

2013-01-01

Our work characterizes the effects of opiate (morphine) dependence on auditory brainstem and visual evoked responses in a rhesus macaque model of neuro-AIDS utilizing a chronic continuous drug delivery paradigm. The goal of this study was to clarify whether morphine is protective, or if it exacerbates simian immunodeficiency virus (SIV) related systemic and neurological disease. Our model employs a macrophage tropic CD4/CCR5 co-receptor virus, SIVmac239 (R71/E17), which crosses the blood brain barrier shortly after inoculation and closely mimics the natural disease course of human immunodeficiency virus (HIV) infection. The cohort was divided into 3 groups: morphine only, SIV only, and SIV + morphine. Evoked potential (EP) abnormalities in sub-clinically infected macaques were evident as early as eight weeks post-inoculation. Prolongations in EP latencies were observed in SIV-infected macaques across all modalities. Animals with the highest CSF viral loads and clinical disease showed more abnormalities than those with sub-clinical disease, confirming our previous work (Raymond et al, 1998, 1999, 2000). Although some differences were observed in auditory and visual evoked potentials in morphine treated compared to untreated SIV-infected animals, the effects were relatively small and not consistent across evoked potential type. However, morphine treated animals with subclinical disease had a clear tendency toward higher virus loads in peripheral and CNS tissues (Marcario et al., 2008) suggesting that if had been possible to follow all animals to end-stage disease, a clearer pattern of evoked potential abnormality might have emerged. PMID:19283490

Mid-latency evoked potentials in self-reported impulsive aggression.

PubMed

Houston, R J; Stanford, M S

2001-02-01

The present study was conducted to examine psychophysiological differences in arousability among individuals who display impulsive aggressive outbursts. Amplitude and latency for the mid-latency evoked potentials (P1, N1 and P2) were obtained at scalp electrode sites. The evoking stimuli were three intensities (low, medium, high) of photic stimulation. Compared to non-aggressive controls, impulsive aggressive subjects showed significantly reduced P1 amplitude, which is indicative of an inefficient sensory gating mechanism. In addition, these subjects exhibited significantly larger N1 amplitude implying an enhanced orienting of attention to stimuli. Impulsive aggressive subjects also exhibited shorter P1, N1 and P2 peak latency. These results suggest that impulsive aggressive individuals may display quicker orienting and processing of stimuli in an attempt to compensate for low resting arousal levels. Finally, impulsive aggressive subjects augmented the P1-N1 component more frequently than controls, which is consistent with previous studies examining impulsivity and sensation seeking. Together, these findings extend previous work concerning the underlying physiology of impulsive aggression. It has been suggested that impulsive aggressive individuals may attempt to compensate for low resting arousal levels by engaging in stimulus seeking behaviors. Accordingly, the present findings imply similar physiological compensatory responses as demonstrated by heightened orienting of attention, processing and arousability. In addition, a compromised sensory gating system in impulsive aggressors may exacerbate such circumstances, and lead to later cognitive processing deficits.

High sensitivity of contact-heat evoked potentials in "snake-eye" appearance myelopathy.

PubMed

Ulrich, A; Min, K; Curt, A

2015-10-01

To evaluate the sensitivity of dermatomal contact-heat evoked potentials (dCHEPs) compared to dermatomal somatosensory evoked potentials (dSSEPs) and clinical sensory testing in patients with focal central cord myelopathy, referred to as "snake-eye" appearance myelopathy (SEAM). 33 patients with SEAM in neuroimaging underwent electrophysiological (dCHEPs, dSSEPs) and clinical testing of sensory function (light touch [LT] and pin prick [PP]) at segments above, at and below to the spinal cord lesion. In total, 151 dermatomes were tested (39 above, 112 at/below lesion). The sensitivity of dCHEPs (97.0%) was significantly higher compared to dSSEPs (23.3%, p<0.001), PP (66.7%, p=0.003) and LT (69.7%, p=0.006), respectively. The sensitivity of dCHEPs was highest when applied one to two segments caudally to the level of spinal cord lesion in MRI. dCHEPs are highly sensitive and superior to dSSEPs and clinical sensory testing in the diagnosis of SEAM. dCHEPs may complement the diagnosis in focal central cord myelopathies where clinical testing of sensory function and dSSEPs are less sensitive to provide conclusive findings. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Brainstem auditory-evoked potentials as an objective tool for evaluating hearing dysfunction in traumatic brain injury.

PubMed

Lew, Henry L; Lee, Eun Ha; Miyoshi, Yasushi; Chang, Douglas G; Date, Elaine S; Jerger, James F

2004-03-01

Because of the violent nature of traumatic brain injury, traumatic brain injury patients are susceptible to various types of trauma involving the auditory system. We report a case of a 55-yr-old man who presented with communication problems after traumatic brain injury. Initial results from behavioral audiometry and Weber/Rinne tests were not reliable because of poor cooperation. He was transferred to our service for inpatient rehabilitation, where review of the initial head computed tomographic scan showed only left temporal bone fracture. Brainstem auditory-evoked potential was then performed to evaluate his hearing function. The results showed bilateral absence of auditory-evoked responses, which strongly suggested bilateral deafness. This finding led to a follow-up computed tomographic scan, with focus on bilateral temporal bones. A subtle transverse fracture of the right temporal bone was then detected, in addition to the left temporal bone fracture previously identified. Like children with hearing impairment, traumatic brain injury patients may not be able to verbalize their auditory deficits in a timely manner. If hearing loss is suspected in a patient who is unable to participate in traditional behavioral audiometric testing, brainstem auditory-evoked potential may be an option for evaluating hearing dysfunction.

Spectrum pattern resolution after noise exposure in a beluga whale, Delphinapterus leucas: Evoked potential study.

PubMed

Popov, Vladimir V; Nechaev, Dmitry I; Sysueva, Evgenia V; Rozhnov, Viatcheslav V; Supin, Alexander Ya

2015-07-01

Temporary threshold shift (TTS) and the discrimination of spectrum patterns after fatiguing noise exposure (170 dB re 1 μPa, 10 min duration) was investigated in a beluga whale, Delphinapterus leucas, using the evoked potential technique. Thresholds were measured using rhythmic (1000/s) pip trains of varying levels and recording the rhythmic evoked responses. Discrimination of spectrum patterns was investigated using rippled-spectrum test stimuli of various levels and ripple densities, recording the rhythmic evoked responses to ripple phase reversals. Before noise exposure, the greatest responses to rippled-spectrum probes were evoked by stimuli with a low ripple density with a decrease in the response magnitude occurring with an increasing ripple density. After noise exposure, both a TTS and a reduction of the responses to rippled-spectrum probes appeared and recovered in parallel. The reduction of the responses to rippled-spectrum probes was maximal for high-magnitude responses at low ripple densities and was negligible for low-magnitude responses at high ripple densities. It is hypothesized that the impacts of fatiguing sounds are not limited by increased thresholds and decreased sensitivity results in reduced ability to discriminate fine spectral content with the greatest impact on the discrimination of spectrum content that may carry the most obvious information about stimulus properties.

Single-trial extraction of cognitive evoked potentials by combination of third-order correlation and wavelet denoising.

PubMed

Zhang, Z; Tian, X

2005-01-01

The application of a recently proposed denoising implementation for obtaining cognitive evoked potentials (CEPs) at the single-trial level is shown. The aim of this investigation is to develop the technique of extracting CEPs by combining both the third-order correlation and the wavelet denoising methods. First, the noisy CEPs was passed through a finite impulse response filter whose impulse response is matched with the shape of the noise-free signal. It was shown that it is possible to estimate the filter impulse response on basis of a select third-order correlation slice (TOCS) of the input noisy CEPs. Second, the output from the third-order correlation filter is decomposed with bi-orthogonal splines at 5 levels. The CEPs is reconstructed by wavelet final approximation a5. We study its performance in simulated data as well as in cognitive evoked potentials of normal rat and Alzheimer's disease (AD) model rat. For the simulated data, the method gives a significantly better reconstruction of the single-trial cognitive evoked potentials responses in comparison with the simulated data. Moreover, with this approach we obtain a significantly better estimation of the amplitudes and latencies of the simulated CEPs. For the real data, the method clearly improves the visualization of single-trial CEPs. This allows the calculation of better averages as well as the study of systematic or unsystematic variations between trials.

Passive attenuation of cortical pattern evoked potentials with increasing body weight in young male rhesus macaques.

PubMed

Komaromy, Andras M; Brooks, Dennis E; Kallberg, Maria E; Dawson, William W; Sapp, Harold L; Sherwood, Mark B; Lambrou, George N; Percicot, Christine L

2003-05-01

The purpose of our study was to determine changes in amplitudes and implicit times of retinal and cortical pattern evoked potentials with increasing body weight in young, growing rhesus macaques (Macaca mulatta). Retinal and cortical pattern evoked potentials were recorded from 29 male rhesus macaques between 3 and 7 years of age. Thirteen animals were reexamined after 11 months. Computed tomography (CT) was performed on two animals to measure the distance between the location of the skin electrode and the surface of the striate cortex. Spearman correlation coefficients were calculated to describe the relationship between body weights and either root mean square (rms) amplitudes or implicit times. For 13 animals rms amplitudes and implicit times were compared with the Wilcoxon matched pairs signed rank test for recordings taken 11 months apart. Highly significant correlations between increases in body weights and decreases in cortical rms amplitudes were noted in 29 monkeys (p < 0.0005). No significant changes were found in the cortical rms amplitudes in thirteen monkeys over 11 months. Computed tomography showed a large increase of soft tissue thickness over the skull and striate cortex with increased body weight. The decreased amplitude in cortical evoked potentials with weight gain associated with aging can be explained by the increased distance between skin electrode and striate cortex due to soft tissue thickening (passive attenuation).

Brainstem auditory evoked potentials with the use of acoustic clicks and complex verbal sounds in young adults with learning disabilities.

PubMed

Kouni, Sophia N; Giannopoulos, Sotirios; Ziavra, Nausika; Koutsojannis, Constantinos

2013-01-01

Acoustic signals are transmitted through the external and middle ear mechanically to the cochlea where they are transduced into electrical impulse for further transmission via the auditory nerve. The auditory nerve encodes the acoustic sounds that are conveyed to the auditory brainstem. Multiple brainstem nuclei, the cochlea, the midbrain, the thalamus, and the cortex constitute the central auditory system. In clinical practice, auditory brainstem responses (ABRs) to simple stimuli such as click or tones are widely used. Recently, complex stimuli or complex auditory brain responses (cABRs), such as monosyllabic speech stimuli and music, are being used as a tool to study the brainstem processing of speech sounds. We have used the classic 'click' as well as, for the first time, the artificial successive complex stimuli 'ba', which constitutes the Greek word 'baba' corresponding to the English 'daddy'. Twenty young adults institutionally diagnosed as dyslexic (10 subjects) or light dyslexic (10 subjects) comprised the diseased group. Twenty sex-, age-, education-, hearing sensitivity-, and IQ-matched normal subjects comprised the control group. Measurements included the absolute latencies of waves I through V, the interpeak latencies elicited by the classical acoustic click, the negative peak latencies of A and C waves, as well as the interpeak latencies of A-C elicited by the verbal stimulus 'baba' created on a digital speech synthesizer. The absolute peak latencies of waves I, III, and V in response to monoaural rarefaction clicks as well as the interpeak latencies I-III, III-V, and I-V in the dyslexic subjects, although increased in comparison with normal subjects, did not reach the level of a significant difference (p<0.05). However, the absolute peak latencies of the negative wave C and the interpeak latencies of A-C elicited by verbal stimuli were found to be increased in the dyslexic group in comparison with the control group (p=0.0004 and p=0.045, respectively

Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials.

PubMed

Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

2015-01-01

Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound

Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials

PubMed Central

Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

2015-01-01

Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound

Cortical Auditory Evoked Potentials with Simple (Tone Burst) and Complex (Speech) Stimuli in Children with Cochlear Implant

PubMed Central

Martins, Kelly Vasconcelos Chaves; Gil, Daniela

2017-01-01

Introduction  The registry of the component P1 of the cortical auditory evoked potential has been widely used to analyze the behavior of auditory pathways in response to cochlear implant stimulation. Objective  To determine the influence of aural rehabilitation in the parameters of latency and amplitude of the P1 cortical auditory evoked potential component elicited by simple auditory stimuli (tone burst) and complex stimuli (speech) in children with cochlear implants. Method  The study included six individuals of both genders aged 5 to 10 years old who have been cochlear implant users for at least 12 months, and who attended auditory rehabilitation with an aural rehabilitation therapy approach. Participants were submitted to research of the cortical auditory evoked potential at the beginning of the study and after 3 months of aural rehabilitation. To elicit the responses, simple stimuli (tone burst) and complex stimuli (speech) were used and presented in free field at 70 dB HL. The results were statistically analyzed, and both evaluations were compared. Results  There was no significant difference between the type of eliciting stimulus of the cortical auditory evoked potential for the latency and the amplitude of P1. There was a statistically significant difference in the P1 latency between the evaluations for both stimuli, with reduction of the latency in the second evaluation after 3 months of auditory rehabilitation. There was no statistically significant difference regarding the amplitude of P1 under the two types of stimuli or in the two evaluations. Conclusion  A decrease in latency of the P1 component elicited by both simple and complex stimuli was observed within a three-month interval in children with cochlear implant undergoing aural rehabilitation. PMID:29018498

The Effectiveness of FES-Evoked EMG Potentials to Assess Muscle Force and Fatigue in Individuals with Spinal Cord Injury

PubMed Central

Ibitoye, Morufu Olusola; Estigoni, Eduardo H.; Hamzaid, Nur Azah; Wahab, Ahmad Khairi Abdul; Davis, Glen M.

2014-01-01

The evoked electromyographic signal (eEMG) potential is the standard index used to monitor both electrical changes within the motor unit during muscular activity and the electrical patterns during evoked contraction. However, technical and physiological limitations often preclude the acquisition and analysis of the signal especially during functional electrical stimulation (FES)-evoked contractions. Hence, an accurate quantification of the relationship between the eEMG potential and FES-evoked muscle response remains elusive and continues to attract the attention of researchers due to its potential application in the fields of biomechanics, muscle physiology, and rehabilitation science. We conducted a systematic review to examine the effectiveness of eEMG potentials to assess muscle force and fatigue, particularly as a biofeedback descriptor of FES-evoked contractions in individuals with spinal cord injury. At the outset, 2867 citations were identified and, finally, fifty-nine trials met the inclusion criteria. Four hypotheses were proposed and evaluated to inform this review. The results showed that eEMG is effective at quantifying muscle force and fatigue during isometric contraction, but may not be effective during dynamic contractions including cycling and stepping. Positive correlation of up to r = 0.90 (p < 0.05) between the decline in the peak-to-peak amplitude of the eEMG and the decline in the force output during fatiguing isometric contractions has been reported. In the available prediction models, the performance index of the eEMG signal to estimate the generated muscle force ranged from 3.8% to 34% for 18 s to 70 s ahead of the actual muscle force generation. The strength and inherent limitations of the eEMG signal to assess muscle force and fatigue were evident from our findings with implications in clinical management of spinal cord injury (SCI) population. PMID:25025551

Facilitation and refractoriness of the electrically evoked compound action potential.

PubMed

Hey, Matthias; Müller-Deile, Joachim; Hessel, Horst; Killian, Matthijs

2017-11-01

In this study we aim to resolve the contributions of facilitation and refractoriness at very short pulse intervals. Measurements of the refractory properties of the electrically evoked compound action potential (ECAP) of the auditory nerve in cochlear implant (CI) users at inter pulse intervals below 300 μs are influenced by facilitation and recovery effects. ECAPs were recorded using masker pulses with a wide range of current levels relative to the probe pulse levels, for three suprathreshold probe levels and pulse intervals from 13 to 200 μs. Evoked potentials were measured for 21 CI patients by using the masked response extraction artifact cancellation procedure. During analysis of the measurements the stimulation current was not used as absolute value, but in relation to the patient's individual ECAP threshold. This enabled a more general approach to describe facilitation as a probe level independent effect. Maximum facilitation was found for all tested inter pulse intervals at masker levels near patient's individual ECAP threshold, independent from probe level. For short inter pulse intervals an increased N 1 P 1 amplitude was measured for subthreshold masker levels down to 120 CL below patient's individual ECAP threshold in contrast to the recreated state. ECAPs recorded with inter pulse intervals up to 200 μs are influenced by facilitation and recovery. Facilitation effects are most pronounced for masker levels at or below ECAP threshold, while recovery effects increase with higher masker levels above ECAP threshold. The local maximum of the ECAP amplitude for masker levels around ECAP threshold can be explained by the mutual influence of maximum facilitation and minimal refractoriness. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Effect of head circumference on parameters of pattern reversal visual evoked potential in healthy adults of central India.

PubMed

Kothari, R; Singh, R; Singh, S; Bokariya, P

2012-06-01

Visual evoked response testing has been one of the most exciting clinical tools to be developed from neurophysiologic research in recent years and has provided us with an objective method of identifying abnormalities of the afferent visual pathways. Investigation were carried out to see whether the head circumference influence the pattern reversal visual evoked potential (PRVEP) parameters. The study comprised of pattern reversal visual evoked potential (PRVEP) recordings in 400 eyes of 200 normal subjects. Two hundred fourty eight eyes were males and 152 eyes were from 76 female subjects recruited from the Central Indian population in the age range of 40-79 years. Visual evoked potential (VEP) recordings were performed in accordance to the standardized methodology of International Federation of Clinical Neurophysiology (IFCN) Committee Recommendations and International Society for Clinical Electrophysiology of Vision (ISCEV) Guidelines and montages were kept as per 10-20 International System of EEG Electrode placements. The stimulus configuration in this study consisted of the transient pattern reversal method in which a black and white checker board was generated (full field) and displayed on a VEP Monitor by an electronic pattern regenerator inbuilt in an Evoked Potential Recorder (RMS EMG EP MARK II). VEP latencies, duration and amplitude were measured in all subjects and the data were analyzed. The correlation of all the electrophysiological parameters with head circumference was evaluated by Pearson's correlation co-efficient (r) and its statistical significance was evaluated. The prediction equations for all the VEP parameters with respect to head circumference were derived. We found a positive correlation of P 100 latency and N 155 latency with mean head circumference, while a highly significant negative correlation were noted of P 100 amplitude with head circumference. N 70 latency was significantly correlated with head circumference. P 100 duration showed

Potential for application of an acoustic camera in particle tracking velocimetry.

PubMed

Wu, Fu-Chun; Shao, Yun-Chuan; Wang, Chi-Kuei; Liou, Jim

2008-11-01

We explored the potential and limitations for applying an acoustic camera as the imaging instrument of particle tracking velocimetry. The strength of the acoustic camera is its usability in low-visibility environments where conventional optical cameras are ineffective, while its applicability is limited by lower temporal and spatial resolutions. We conducted a series of experiments in which acoustic and optical cameras were used to simultaneously image the rotational motion of tracer particles, allowing for a comparison of the acoustic- and optical-based velocities. The results reveal that the greater fluctuations associated with the acoustic-based velocities are primarily attributed to the lower temporal resolution. The positive and negative biases induced by the lower spatial resolution are balanced, with the positive ones greater in magnitude but the negative ones greater in quantity. These biases reduce with the increase in the mean particle velocity and approach minimum as the mean velocity exceeds the threshold value that can be sensed by the acoustic camera.

Auditory- and Visual-Evoked Potentials in Mexican Infants Are Not Affected by Maternal Supplementation with 400 mg/d Docosahexaenoic Acid in the Second Half of Pregnancy1234

PubMed Central

Stein, Aryeh D.; Wang, Meng; Rivera, Juan A.; Martorell, Reynaldo; Ramakrishnan, Usha

2012-01-01

The evidence relating prenatal supplementation with DHA to offspring neurological development is limited. We investigated the effect of prenatal DHA supplementation on infant brainstem auditory-evoked responses and visual- evoked potentials in a double-blind, randomized controlled trial in Cuernavaca, Mexico. Pregnant women were supplemented daily with 400 mg DHA or placebo from gestation wk 18–22 through delivery. DHA and placebo groups did not differ in maternal characteristics at randomization or infant characteristics at birth. Brainstem auditory-evoked responses were measured at 1 and 3 mo in 749 and 664 infants, respectively, and visual-evoked potentials were measured at 3 and 6 mo in 679 and 817 infants, respectively. Left-right brainstem auditory-evoked potentials were moderately correlated (range, 0.26–0.43; all P < 0.001) and left-right visual-evoked potentials were strongly correlated (range, 0.79–0.94; all P < 0.001) within any assessment. Correlations across visits were modest to moderate (range, 0.09–0.38; all P < 0.01). The offspring of DHA-supplemented women did not differ from those of control women with respect to any outcome measure (all comparisons P > 0.10). We conclude that DHA supplementation during pregnancy did not influence brainstem auditory-evoked responses at 1 and 3 mo or visual-evoked potentials at 3 and 6 mo. PMID:22739364

Analysis of the Averaged Visually Evoked Potentials in Normal Children. (RIEEC Research Bulletin 3.)

ERIC Educational Resources Information Center

Mizutani, Tohru; And Others

Evaluated were the properties and fine structures of averaged visually evoked potentials (AVEP) in 60 normal children between the ages of 2 and 9 years. Electroencephalographic recordings were taken while white diffuse flashes were used to deliver visual stimuli to the Ss. Three types of AVEP patterns were discerned, with no relationship observed…

Attentional Modulation of Visual-Evoked Potentials by Threat: Investigating the Effect of Evolutionary Relevance

ERIC Educational Resources Information Center

Brown, Christopher; El-Deredy, Wael; Blanchette, Isabelle

2010-01-01

In dot-probe tasks, threatening cues facilitate attention to targets and enhance the amplitude of the target P1 peak of the visual-evoked potential. While theories have suggested that evolutionarily relevant threats should obtain preferential neural processing, this has not been examined empirically. In this study we examined the effects of…

Unpredictable interference of new transcranial motor-evoked potential monitor against the implanted pacemaker.

PubMed

Hayashi, Kazuko

2016-12-01

Recently, NuVasive NV-M5 nerve monitoring system, a new transcranial motor-evoked potential (TcMEP) monitor, has been introduced with the spread of flank-approach spinal operations such as extreme lateral interbody fusion, to prevent nerve damage. Conventional TcMEP monitors use changes in MEP wave patterns, such as amplitude and/or latency, whereas the NV-M5 nerve monitor system first measures the MEP baseline waveform from the transcranial-evoked potential then measures the electric current necessary to obtain the standard of the previous baseline wave pattern at subsequent monitoring times. The NV-M5 monitor determines nerve damage according to the increase in necessary electric current threshold. The NV-M5 monitor also uses a local electrical stimulation mode to monitor the safety of setting screws into the lumbar vertebrae. In this way, various electrical stimulations with various durations and frequencies are used, and electrical noise may result in unpredictable interference with cardiac pacemakers. We performed anesthetic management of extreme lateral interbody fusion surgery using the NV-M5 in a patient with an implanted pacemaker, during which TcMEP stimulation caused interference with the implanted pacemaker. Copyright © 2016 Elsevier Inc. All rights reserved.

Physiological, anatomical, and behavioral changes after acoustic trauma in Drosophila melanogaster

PubMed Central

Christie, Kevin W.; Sivan-Loukianova, Elena; Smith, Wesley C.; Aldrich, Benjamin T.; Schon, Michael A.; Roy, Madhuparna; Lear, Bridget C.; Eberl, Daniel F.

2013-01-01

Noise-induced hearing loss (NIHL) is a growing health issue, with costly treatment and lost quality of life. Here we establish Drosophila melanogaster as an inexpensive, flexible, and powerful genetic model system for NIHL. We exposed flies to acoustic trauma and quantified physiological and anatomical effects. Trauma significantly reduced sound-evoked potential (SEP) amplitudes and increased SEP latencies in control genotypes. SEP amplitude but not latency effects recovered after 7 d. Although trauma produced no gross morphological changes in the auditory organ (Johnston’s organ), mitochondrial cross-sectional area was reduced 7 d after exposure. In nervana 3 heterozygous flies, which slightly compromise ion homeostasis, trauma had exaggerated effects on SEP amplitude and mitochondrial morphology, suggesting a key role for ion homeostasis in resistance to acoustic trauma. Thus, Drosophila exhibit acoustic trauma effects resembling those found in vertebrates, including inducing metabolic stress in sensory cells. This report of noise trauma in Drosophila is a foundation for studying molecular and genetic sequelae of NIHL. PMID:24003166

Large Amplitude Cortical Evoked Potentials in Nonepileptic Patients. Reviving an Old Neurophysiologic Tool to Help Detect CNS Pathology.

PubMed

Martín-Palomeque, Guillermo; Castro-Ortiz, Antonio; Pamplona-Valenzuela, Pilar; Saiz-Sepúlveda, Miguel Á; Cabañes-Martínez, Lidia; López, Jaime R

2017-01-01

Although large amplitude evoked potentials (EPs) are typically associated with progressive myoclonic epilepsy patients, giant EPs imply central nervous system (CNS) hyperexcitability and can be seen in various nonepileptic disorders. We performed a retrospective chart review including history, physical examination, imaging and diagnostic studies of nonepileptic patients with large amplitude somatosensory evoked potentials (SSEPs) and visual evoked potentials (VEPs) during 2007 to 2013. Large amplitude EPs were defined as follows: VEPs (N75-P100) >18 μV; and SSEPs (N20-P25) >6.4 μV. Recording montage for VEPs was Oz-Cz and SSEPs C3'/C4'-Fz. Fifty-two patients (33 females, 19 males; age range, 9-90 years) were identified. No CNS pathology was detected in 7 patients. All remaining patients were diagnosed with new CNS disorders including: vascular (37%); myelopathies (13%); demyelinating (11%); space occupying lesions (8.7%); syringomyelia (8.7%); hydrocephalus (6.5%); Vitamin B-12 deficiency (4.3%); multiple system atrophy (4.3%); and toxins (2.2%). This study supports the notion that large amplitude EP implies CNS hyperexcitability and CNS disease. These results confirm the utility of EP studies in patients with suspected CNS pathology.

Correlation of pattern reversal visual evoked potential parameters with the pattern standard deviation in primary open angle glaucoma.

PubMed

Kothari, Ruchi; Bokariya, Pradeep; Singh, Ramji; Singh, Smita; Narang, Purvasha

2014-01-01

To evaluate whether glaucomatous visual field defect particularly the pattern standard deviation (PSD) of Humphrey visual field could be associated with visual evoked potential (VEP) parameters of patients having primary open angle glaucoma (POAG). Visual field by Humphrey perimetry and simultaneous recordings of pattern reversal visual evoked potential (PRVEP) were assessed in 100 patients with POAG. The stimulus configuration for VEP recordings consisted of the transient pattern reversal method in which a black and white checker board pattern was generated (full field) and displayed on VEP monitor (colour 14″) by an electronic pattern regenerator inbuilt in an evoked potential recorder (RMS EMG EP MARK II). The results of our study indicate that there is a highly significant (P<0.001) negative correlation of P100 amplitude and a statistically significant (P<0.05) positive correlation of N70 latency, P100 latency and N155 latency with the PSD of Humphrey visual field in the subjects of POAG in various age groups as evaluated by Student's t-test. Prolongation of VEP latencies were mirrored by a corresponding increase of PSD values. Conversely, as PSD increases the magnitude of VEP excursions were found to be diminished.

Reduced laser-evoked potential habituation detects abnormal central pain processing in painful radiculopathy patients.

PubMed

Hüllemann, P; von der Brelie, C; Manthey, G; Düsterhöft, J; Helmers, A K; Synowitz, M; Baron, R

2017-05-01

Repetitive painful laser stimuli lead to physiological laser-evoked potential (LEP) habituation, measurable by a decrement of the N2/P2 amplitude. The time course of LEP-habituation is reduced in the capsaicin model for peripheral and central sensitization and in patients with migraine and fibromyalgia. In the present investigation, we aimed to assess the time course of LEP-habituation in a neuropathic pain syndrome, i.e. painful radiculopathy. At the side of radiating pain, four blocks of 25 painful laser stimuli each were applied to the ventral thigh at the L3 dermatome in 27 patients with painful radiculopathy. Inclusion criteria were (1) at least one neurological finding of radiculopathy, (2) low back pain with radiation into the foot and (3) a positive one-sided compression of the L5 and/or S1 root in the MRI. The time course of LEP-habituation was compared to 20 healthy height and age matched controls. Signs of peripheral (heat hyperalgesia) and central sensitization (dynamic mechanical allodynia and hyperalgesia) at the affected L5 or S1 dermatome were assessed with quantitative sensory testing. Painful radiculopathy patients showed decreased LEP-habituation compared to controls. Patients with signs of central sensitization showed a more prominent LEP-habituation decrease within the radiculopathy patient group. Laser-evoked potential habituation is reduced in painful radiculopathy patients, which indicates an abnormal central pain processing. Central sensitization seems to be a major contributor to abnormal LEP habituation. The LEP habituation paradigm might be useful as a clinical tool to assess central pain processing alterations in nociceptive and neuropathic pain conditions. Abnormal central pain processing in neuropathic pain conditions may be revealed with the laser-evoked potential habituation paradigm. In painful radiculopathy patients, LEP-habituation is reduced compared to healthy controls. © 2017 European Pain Federation - EFIC®.

Emotional body-word conflict evokes enhanced n450 and slow potential.

PubMed

Ma, Jianling; Liu, Chang; Zhong, Xin; Wang, Lu; Chen, Xu

2014-01-01

Emotional conflict refers to the influence of task irrelevant affective stimuli on current task set. Previously used emotional face-word tasks have produced certain electrophysiological phenomena, such as an enhanced N450 and slow potential; however, it remains unknown whether these effects emerge in other tasks. The present study used an emotional body-word conflict task to investigate the neural dynamics of emotional conflict as reflected by response time, accuracy, and event-related potentials, which were recorded with the aim of replicating the previously observed N450 and slow potential effect. Results indicated increased response time and decreased accuracy in the incongruent condition relative to the congruent condition, indicating a robust interference effect. Furthermore, the incongruent condition evoked pronounced N450 amplitudes and a more positive slow potential, which might be associated with conflict-monitoring and conflict resolution. The present findings extend our understanding of emotional conflict to the body-word domain.

Hearing outcomes after loss of brainstem auditory evoked potentials during microvascular decompression.

PubMed

Thirumala, Parthasarathy D; Krishnaiah, Balaji; Habeych, Miguel E; Balzer, Jeffrey R; Crammond, Donald J

2015-04-01

The primary aim of this paper is to study the pre-operative characteristics, intra-operative changes and post-operative hearing outcomes in patients after complete loss of wave V of the brainstem auditory evoked potential. We retrospectively analyzed the brainstem auditory evoked potential data of 94 patients who underwent microvascular decompression for hemifacial spasm at our institute. Patients were divided into two groups - those with and those without loss of wave V. The differences between the two groups and outcomes were assessed using t-test and chi-squared tests. In our study 23 (24%) patients out of 94 had a complete loss of wave V, with 11 (48%) patients experiencing transient loss and 12 (52%) patients experiencing permanent loss. The incidence of hearing loss in patients with no loss of wave V was 5.7% and 26% in patients who did experience wave V loss. The incidence of hearing change in patients with no loss of wave V was 12.6% and 30.43% in patients who did experience wave V loss. Loss of wave V during the procedure or at the end of procedure significantly increases the odds of hearing loss. Hearing change is a significant under-reported clinical condition after microvascular decompression in patients who have loss of wave V. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of electrical boundary conditions on profiles of acoustic field and electric potential of shear-horizontal acoustic waves in potassium niobate plates.

PubMed

Kuznetsova, I E; Nedospasov, I A; Kolesov, V V; Qian, Z; Wang, B; Zhu, F

2018-05-01

The profiles of an acoustic field and electric potential of the forward and backward shear-horizontal (SH) acoustic waves of a higher order propagating in X-Y potassium niobate plate have been theoretically investigated. It has been shown that by changing electrical boundary conditions on a surface of piezoelectric plates, it is possible to change the distributions of an acoustic field and electric potential of the forward and backward acoustic waves. The dependencies of the distribution of a mechanical displacement and electrical potential over the plate thickness for electrically open and electrically shorted plates have been plotted. The influence of a layer with arbitrary conductivity placed on a one or on the both plate surfaces on the profiles under study, phase and group velocities of the forward and backward acoustic waves in X-Y potassium niobate has been also investigated. The obtained results can be useful for development of the method for control of a particle or electrical charge movement inside the piezoelectric plates, as well a sensor for definition of the thin film conductivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Relationship between endolymphatic hydrops and vestibular-evoked myogenic potential.

PubMed

Katayama, Naomi; Yamamoto, Masako; Teranishi, Masaaki; Naganawa, Shinji; Nakata, Seiichi; Sone, Michihiko; Nakashima, Tsutomu

2010-08-01

Vestibular-evoked myogenic potential (VEMP) can be used to examine endolymphatic hydrops, especially in the vestibule. To investigate the relationship between the degree of endolymphatic hydrops revealed by magnetic resonance imaging (MRI) and VEMP. Gadolinium diluted with saline was injected intratympanically in 49 ears (40 patients). One day after the injection, the endolymphatic space in the vestibule and the cochlea was visualized by 3 Tesla MRI. A VEMP test was done, and VEMP was judged as absent when the VEMP was within the noise level. VEMP was present in 21 ears and absent in 28 ears. Endolymphatic hydrops was significantly associated with the disappearance of VEMP. Endolymphatic hydrops in the vestibule had a stronger effect than endolymphatic hydrops in the cochlea. Five patients with extremely large vestibular hydrops showed no response of VEMP.

[Determination of irreversibility of clinical brain death. Electroencephalography and evoked potentials].

PubMed

Buchner, H; Ferbert, A

2016-02-01

Principally, in the fourth update of the rules for the procedure to finally determine the irreversible cessation of function of the cerebrum, the cerebellum and the brainstem, the importance of an electroencephalogram (EEG), somatosensory evoked potentials (SEP) and brainstem auditory evoked potentials (BAEP) are confirmed. This paper presents the reliability and validity of the electrophysiological diagnosis, discusses the amendments in the fourth version of the guidelines and introduces the practical application, problems and sources of error.An EEG is the best established supplementary diagnostic method for determining the irreversibility of clinical brain death syndrome. It should be noted that residual brain activity can often persist for many hours after the onset of brain death syndrome, particularly in patients with primary brainstem lesions. The derivation and analysis of an EEG requires a high level of expertise to be able to safely distinguish artefacts from primary brain activity. The registration of EEGs to demonstrate the irreversibility of clinical brain death syndrome is extremely time consuming.The BAEPs can only be used to confirm the irreversibility of brain death syndrome in serial examinations or in the rare cases of a sustained wave I or sustained waves I and II. Very often, an investigation cannot be reliably performed because of existing sound conduction disturbances or failure of all potentials even before the onset of clinical brain death syndrome. This explains why BAEPs are only used in exceptional cases.The SEPs of the median nerve can be very reliably derived, are technically simple and with few sources of error. A serial investigation is not required and the time needed for examination is short. For these reasons SEPs are given preference over EEGs and BAEPs for establishing the irreversibility of clinical brain death syndrome.

Can Vestibular-Evoked Myogenic Potentials Help Differentiate Ménière Disease from Vestibular Migraine?

PubMed Central

Zuniga, M. Geraldine; Janky, Kristen L.; Schubert, Michael C.; Carey, John P.

2013-01-01

Objectives To characterize both cervical and ocular vestibular-evoked myogenic potential (cVEMP, oVEMP) responses to air-conducted sound (ACS) and midline taps in Ménière disease (MD), vestibular migraine (VM), and controls, as well as to determine if cVEMP or oVEMP responses can differentiate MD from VM. Study Design Prospective cohort study. Setting Tertiary referral center. Subjects and Methods Unilateral definite MD patients (n = 20), VM patients (n = 21) by modified Neuhauser criteria, and age-matched controls (n = 28). cVEMP testing used ACS (clicks), and oVEMP testing used ACS (clicks and 500-Hz tone bursts) and midline tap stimuli (reflex hammer and Mini-Shaker). Outcome parameters were cVEMP peak-to-peak amplitudes and oVEMP n10 amplitudes. Results Relative to controls, MD and VM groups both showed reduced click-evoked cVEMP (P < .001) and oVEMP (P < .001) amplitudes. Only the MD group showed reduction in tone-evoked amplitudes for oVEMP. Tone-evoked oVEMPs differentiated MD from controls (P = .001) and from VM (P = .007). The oVEMPs in response to the reflex hammer and Mini-Shaker midline taps showed no differences between groups (P > .210). Conclusions Using these techniques, VM and MD behaved similarly on most of the VEMP test battery. A link in their pathophysiology may be responsible for these responses. The data suggest a difference in 500-Hz tone burst–evoked oVEMP responses between MD and MV as a group. However, no VEMP test that was investigated segregated individuals with MD from those with VM. PMID:22267492

Electrocortical effects of MDMA are potentiated by acoustic stimulation in rats

PubMed Central

Iannone, Michelangelo; Bulotta, Stefania; Paolino, Donatella; Zito, Maria Cristina; Gratteri, Santo; Costanzo, Francesco S; Rotiroti, Domenicantonio

2006-01-01

Background 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is known for its toxicological, psychopathological and abuse potential. Some environmental conditions, e.g. acoustic stimulation typical of the "rave scene" can influence the toxicity of this drug. Results We investigated the effects of low doses of MDMA in vivo using Wistar rats in the absence of acoustic stimulation (white noise; 95 Db) demonstrating that ecstasy is able to induce a significant activation (reduction of Electrocortical total power) of the telencephalic cortex that spontaneously reverts in the absence of sensorial stimuli, whereas it persists for several days if, in addition to MDMA, the animals are exposed to acoustic stimulation. Conclusion Our data demonstrate that low doses of MDMA are able to reduce electrocortical total power, and that this effect is potentiated by sensorial stimuli commonly present in certain environments, such as rave parties. PMID:16480519

Electrocortical effects of MDMA are potentiated by acoustic stimulation in rats.

PubMed

Iannone, Michelangelo; Bulotta, Stefania; Paolino, Donatella; Zito, Maria Cristina; Gratteri, Santo; Costanzo, Francesco S; Rotiroti, Domenicantonio

2006-02-16

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is known for its toxicological, psychopathological and abuse potential. Some environmental conditions, e.g. acoustic stimulation typical of the "rave scene" can influence the toxicity of this drug. We investigated the effects of low doses of MDMA in vivo using Wistar rats in the absence of acoustic stimulation (white noise; 95 Db) demonstrating that ecstasy is able to induce a significant activation (reduction of Electrocortical total power) of the telencephalic cortex that spontaneously reverts in the absence of sensorial stimuli, whereas it persists for several days if, in addition to MDMA, the animals are exposed to acoustic stimulation. Our data demonstrate that low doses of MDMA are able to reduce electrocortical total power, and that this effect is potentiated by sensorial stimuli commonly present in certain environments, such as rave parties.

Binaural Interaction in Specific Language Impairment: An Auditory Evoked Potential Study

ERIC Educational Resources Information Center

Clarke, Elaine M; Adams, Catherine

2007-01-01

The aim of the study was to examine whether auditory binaural interaction, defined as any difference between binaurally evoked responses and the sum of monaurally evoked responses, which is thought to index functions involved in the localization and detection of signals in background noise, is atypical in a group of children with specific language…

Cervical Vestibular-Evoked Myogenic Potentials: Norms and Protocols

PubMed Central

Isaradisaikul, Suwicha; Navacharoen, Niramon; Hanprasertpong, Charuk; Kangsanarak, Jaran

2012-01-01

Vestibular-evoked myogenic potential (VEMP) testing is a vestibular function test used for evaluating saccular and inferior vestibular nerve function. Parameters of VEMP testing include VEMP threshold, latencies of p1 and n1, and p1-n1 interamplitude. Less commonly used parameters were p1-n1 interlatency, interaural difference of p1 and n1 latency, and interaural amplitude difference (IAD) ratio. This paper recommends using air-conducted 500 Hz tone burst auditory stimulation presented monoaurally via an inserted ear phone while the subject is turning his head to the contralateral side in the sitting position and recording the responses from the ipsilateral sternocleidomastoid muscle. Normative values of VEMP responses in 50 normal audiovestibular volunteers were presented. VEMP testing protocols and normative values in other literature were reviewed and compared. The study is beneficial to clinicians as a reference guide to set up VEMP testing and interpretation of the VEMP responses. PMID:22577386

EEG, evoked potentials and pulsed Doppler in asphyxiated term infants.

PubMed

Julkunen, Mia K; Himanen, Sari-Leena; Eriksson, Kai; Janas, Martti; Luukkaala, Tiina; Tammela, Outi

2014-09-01

To evaluate electroencephalograms (EEG), evoked potentials (EPs) and Doppler findings in the cerebral arteries as predictors of a 1-year outcome in asphyxiated newborn infants. EEG and EPs (brain stem auditory (BAEP), somatosensory (SEP), visual (VEP) evoked potentials) were assessed in 30 asphyxiated and 30 healthy term infants during the first days (range 1-8). Cerebral blood flow velocities (CBFV) were measured from the cerebral arteries using pulsed Doppler at ∼24h of age. EEG, EPs, Doppler findings, symptoms of hypoxic ischemic encephalopathy (HIE) and their combination were evaluated in predicting a 1-year outcome. An abnormal EEG background predicted poor outcome in the asphyxia group with a sensitivity of 67% and 81% specificity, and an abnormal SEP with 75% and 79%, respectively. Combining increased systolic CBFV (mean+3SD) with abnormal EEG or SEP improved the specificity, but not the sensitivity. The predictive values of abnormal BAEP and VEP were poor. Normal EEG and SEP predicted good outcome in the asphyxia group with sensitivities from 79% to 81%. The combination of normal EEG, normal SEP and systolic CBFV<3SD predicted good outcome with a sensitivity of 74% and 100% specificity. Combining abnormal EEG or EPs findings with increased systolic CBFV did not improve prediction of a poor 1-year outcome of asphyxiated infants. Normal EEG and normal SEP combined with systolic CBFV<3SD at about 24 h can be valuable in the prediction of normal 1-year outcome. Combining systolic CBFV at 24 h with EEG and SEP examinations can be of use in the prediction of normal 1-year outcome among asphyxiated infants. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Deep brain stimulation of the ventral hippocampus restores deficits in processing of auditory evoked potentials in a rodent developmental disruption model of schizophrenia

PubMed Central

Ewing, Samuel G.; Grace, Anthony A.

2012-01-01

Existing antipsychotic drugs are most effective at treating the positive symptoms of schizophrenia, but their relative efficacy is low and they are associated with considerable side effects. In this study deep brain stimulation of the ventral hippocampus was performed in a rodent model of schizophrenia (MAM-E17) in an attempt to alleviate one set of neurophysiological alterations observed in this disorder. Bipolar stimulating electrodes were fabricated and implanted, bilaterally, into the ventral hippocampus of rats. High frequency stimulation was delivered bilaterally via a custom-made stimulation device and both spectral analysis (power and coherence) of resting state local field potentials and amplitude of auditory evoked potential components during a standard inhibitory gating paradigm were examined. MAM rats exhibited alterations in specific components of the auditory evoked potential in the infralimbic cortex, the core of the nucleus accumbens, mediodorsal thalamic nucleus, and ventral hippocampus in the left hemisphere only. DBS was effective in reversing these evoked deficits in the infralimbic cortex and the mediodorsal thalamic nucleus of MAM-treated rats to levels similar to those observed in control animals. In contrast stimulation did not alter evoked potentials in control rats. No deficits or stimulation-induced alterations were observed in the prelimbic and orbitofrontal cortices, the shell of the nucleus accumbens or ventral tegmental area. These data indicate a normalization of deficits in generating auditory evoked potentials induced by a developmental disruption by acute high frequency, electrical stimulation of the ventral hippocampus. PMID:23269227

Visual evoked potentials of mildly mentally retarded and control children.

PubMed

Gasser, T; Pietz, J; Schellberg, D; Köhler, W

1988-10-01

Visual evoked potentials (VEPs) were recorded from 25 10- to 13-year-old mildly mentally retarded children and compared with those from 31 control children of the same age-range. Correlations of VEPs with age were weak, but a relationship between VEPs and IQ was demonstrated for the control group. The retarded group had significantly longer latencies and higher amplitude peaks than the control group, with the differences occurring primarily over non-specific cortex and for secondary components. Analysis also showed that the retarded group were neurophysiologically heterogeneous. Since the same children had been analyzed earlier by quantitative EEG methods, comparisons are made with respect to these two methods of investigating brain function.

Effects of core body temperature on changes in spinal somatosensory-evoked potential in acute spinal cord compression injury: an experimental study in the rat.

PubMed

Jou, I M

2000-08-01

Acute spinal cord injury was induced by a clip compression model in rats to approximate spinal cord injury encountered in spinal surgery. Spinal somatosensory-evoked potential neuromonitoring was used to study the electrophysiologic change. To compare and correlate changes in evoked potential after acute compression at different core temperatures with postoperative neurologic function and histologic change, to evaluate current intraoperative neuromonitoring warning criteria for neural damage, and to confirm the protective effect of hypothermia in acute spinal cord compression injury by electrophysiologic, histologic, and clinical observation. With the increase in aggressive correction of spinal deformities, and the invasiveness of surgical instruments, the incidence of neurologic complication appears to have increased despite the availability of sensitive intraoperative neuromonitoring techniques designed to alert surgeons to impending neural damage. Many reasons have been given for the frequent failures of neuromonitoring, but the influence of temperature-a very important and frequently encountered factor-on evoked potential has not been well documented. Specifically, decrease in amplitude and elongation of latency seem not to have been sufficiently taken into account when intraoperative neuromonitoring levels were interpreted and when acceptable intraoperative warning criteria were determined. Experimental acute spinal cord injury was induced in rats by clip compression for two different intervals and at three different core temperatures. Spinal somatosensory-evoked potential, elicited by stimulating the median nerve and recorded from the cervical interspinous C2-C3, was monitored immediately before and after compression, and at 15-minute intervals for 1 hour. Spinal somatosensory-evoked potential change is almost parallel to temperature-based amplitude reduction and latency elongation. Significant neurologic damage induced by acute compression of the cervical

Sensitivity of visual evoked potentials and spectral domain optical coherence tomography in early relapsing remitting multiple sclerosis.

PubMed

Behbehani, Raed; Ahmed, Samar; Al-Hashel, Jasem; Rousseff, Rossen T; Alroughani, Raed

2017-02-01

Visual evoked potentials and spectral-domain optical coherence tomography are common ancillary studies that assess the visual pathways from a functional and structural aspect, respectively. To compare prevalence of abnormalities of Visual evoked potentials (VEP) and spectral-domain optical coherence tomography (SDOCT) in patients with relapsing remitting multiple sclerosis (RRMS). A cross-sectional study of 100 eyes with disease duration of less than 5 years since the diagnosis. Correlation between retinal nerve fiber layer and ganglion-cell/inner plexiform layer with pattern-reversal visual evoked potentials amplitude and latency and contrast sensitivity was performed. The prevalence of abnormalities in pattern-reversal visual VEP was 56% while that of SOCT was 48% in all eyes. There was significant negative correlations between the average RNFL (r=-0.34, p=0.001) and GCIPL (r=-0.39, p<0.001) with VEP latency. In eyes with prior optic neuritis, a significant negative correlation was seen between average RNFL (r=-0.33, p=0.037) and GCIPL (r=-0.40, p=0.010) with VEP latency. We have found higher prevalence of VEP abnormalities than SCOCT in early relapsing-remitting multiple sclerosis. This suggests that VEP has a higher sensitivity for detecting lesions of the visual pathway in patients with early RRMS. Copyright © 2016 Elsevier B.V. All rights reserved.

Vestibular-evoked myogenic potentials, clinical evaluation, and imaging findings in multiple sclerosis.

PubMed

Güven, Hayat; Bayır, Omer; Aytaç, Emrah; Ozdek, Ali; Comoğlu, Selim Selçuk; Korkmaz, Hakan

2014-02-01

Vestibular-evoked myogenic potentials (VEMP), short-latency electromyographic responses elicited by acoustic stimuli, evaluate the function of vestibulocollic reflex and may give information about brainstem function. The aim of the present study is to evaluate the potential contribution of VEMP to the diagnosis of multiple sclerosis (MS). Fifty patients with MS and 30 healthy control subjects were included in this study. The frequency of VEMP p1-n1 and n2-p2 waves; mean p1, n1, n2, and p2 latency; and mean p1-n1 and n2-p2 amplitude were determined. The relation between clinical and imaging findings and VEMP parameters was evaluated. The p1-n1 and n2-p2 waves were more frequently absent in MS than in control subjects [p1-n1 wave absent: MS, 25 (25 %) ears; control, 6 (10 %) ears; P ≤ 0.02] [n2-p2 wave absent: MS, 44 (44 %) ears; control, 7 (12 %) ears; P ≤ 0.001]. The mean p1-n1 amplitude was lower in MS than in control subjects (MS, 19.1 ± 7.2 μV; control, 23.3 ± 7.4 μV; P ≤ 0.002). A total of 24/50 (48 %) MS patients had VEMP abnormalities (absent responses and/or prolonged latencies). VEMP abnormalities were more frequent in patients with than without vestibular symptoms (P ≤ 0.02) and with brainstem functional system score (FSS) ≥ 1 than FSS = 0 (P ≤ 0.02). In patients with MS, absence of p1-n1 wave was more frequent in patients with than without vestibular symptoms [absence of p1-n1 wave: vestibular symptoms, 9 (45 %) ears; no vestibular symptoms, 16 (20 %) ears; P ≤ 0.03] and patients with Expanded Disability Status Scale (EDSS) score ≥ 5.5 [absence of p1-n1 wave: EDSS ≥ 5.5, 7 (70 %) ears; EDSS <5.5, 18 (20 %) ears; P ≤ 0.001]. Abnormal VEMP may be noted in MS patients, especially those with vestibular symptoms and greater disability. The VEMP test may complement other studies for diagnosis and follow-up of patients with MS.

Vestibular evoked myogenic potential findings in multiple sclerosis.

PubMed

Escorihuela García, Vicente; Llópez Carratalá, Ignacio; Orts Alborch, Miguel; Marco Algarra, Jaime

2013-01-01

Multiple sclerosis is an inflammatory disease involving the occurrence of demyelinating, chronic neurodegenerative lesions in the central nervous system. We studied vestibular evoked myogenic potentials (VEMPs) in this pathology, to allow us to evaluate the saccule, inferior vestibular nerve and vestibular-spinal pathway non-invasively. There were 23 patients diagnosed with multiple sclerosis who underwent VEMP recordings, comparing our results with a control group consisting of 35 healthy subjects. We registered p13 and n23 wave latencies, interaural amplitude difference and asymmetry ratio between both ears. Subjects also underwent an otoscopy and audiometric examination. The prolongation of p13 and n23 wave latencies was the most notable characteristic, with a mean p13 wave latency of 19.53 milliseconds and a mean latency of 30.06 milliseconds for n23. In contrast, the asymmetry index showed no significant differences with our control group. In case of multiple sclerosis, the prolongation of the p13 and n23 VEMP wave latencies is a feature that has been attributed to slowing of conduction by demyelination of the vestibular-spinal pathway. In this regard, alteration of the response or lack thereof in these potentials has a locator value of injury to the lower brainstem. Copyright © 2013 Elsevier España, S.L. All rights reserved.

Multimodal evoked potentials in patients with multiple sclerosis in assessment of the course of the disease.

PubMed

Łabuz-Roszak, Beata; Torbus, Magdalena; Kubicka-Bączyk, Katarzyna; Machowska-Majchrzak, Agnieszka; Kierber, Agata; Borucka, Katarzyna; Zellner, Małgorzata; Starostak-Tatar, Anna; Pierzchała, Krystyna

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating disease of the central nervous system with a multifocal damage. The assessment of the MS course by multimodal evoked potentials (EP). We evaluated 95 patients (63 female, 32 male) with relapsing-remitting MS in the average age of 36.4±10.4. The average disease duration was 4.6±7.4 year. Among them, 48 patients (50.5%) were treated with immunomodulatory drugs. All patients underwent neurological examination and EP testing: VEP (visual evoked potentials), SEP (somatosensory evoked potentials), endogenous potential P300. The latencies of following waves were evaluated: P100 (VEP), N4 , N9 , N13, N20, P22 (SEP) and P300, with the reference values of the Neurophysiological Research Laboratory of the Department of Neurology in Zabrze. Abnormal VEP(I) was found in 80 patients (84.2%), SEP(I) in 9 patients (9.5%), P300(I) in 15 patients (15.8%). Abnormal result of the control research VEP (II) was found in 23 patients (82.1%), SEP(II) in 1 patient (3.6%), P300(II) in 4 patients (14.3%). The average values of the waves latencies in the control study were higher, however the statistical significance was not found. The correlation was observed between EDSS, and N20 and P22. No relationship was found between EP and age, disease duration, number of relapses and treatment. In the era of neuroimaging, usage of EP in the diagnosis and assessment of MS is limited. Electrophysiological studies may be used in addition to the clinical examination to confirm the multifocal damage.

Pain-related somatosensory evoked potentials and functional brain magnetic resonance in the evaluation of neurologic recovery after cardiac arrest: a case study of three patients.

PubMed

Zanatta, Paolo; Messerotti Benvenuti, Simone; Baldanzi, Fabrizio; Bendini, Matteo; Saccavini, Marsilio; Tamari, Wadih; Palomba, Daniela; Bosco, Enrico

2012-03-31

This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients.

Gender disparity in subcortical encoding of binaurally presented speech stimuli: an auditory evoked potentials study.

PubMed

Ahadi, Mohsen; Pourbakht, Akram; Jafari, Amir Homayoun; Shirjian, Zahra; Jafarpisheh, Amir Salar

2014-06-01

To investigate the influence of gender on subcortical representation of speech acoustic parameters where simultaneously presented to both ears. Two-channel speech-evoked auditory brainstem responses were obtained in 25 female and 23 male normal hearing young adults by using binaural presentation of the 40 ms synthetic consonant-vowel/da/, and the encoding of the fast and slow elements of speech stimuli at subcortical level were compared in the temporal and spectral domains between the sexes using independent sample, two tailed t-test. Highly detectable responses were established in both groups. Analysis in the time domain revealed earlier and larger Fast-onset-responses in females but there was no gender related difference in sustained segment and offset of the response. Interpeak intervals between Frequency Following Response peaks were also invariant to sex. Based on shorter onset responses in females, composite onset measures were also sex dependent. Analysis in the spectral domain showed more robust and better representation of fundamental frequency as well as the first formant and high frequency components of first formant in females than in males. Anatomical, biological and biochemical distinctions between females and males could alter the neural encoding of the acoustic cues of speech stimuli at subcortical level. Females have an advantage in binaural processing of the slow and fast elements of speech. This could be a physiological evidence for better identification of speaker and emotional tone of voice, as well as better perceiving the phonetic information of speech in women. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Hearing Screening of High-Risk Newborns with Brainstem Auditory Evoked Potentials: A Follow-Up Study.

ERIC Educational Resources Information Center

Shannon, Dorothy A.; And Others

1984-01-01

The brainstem auditory evoked potential (BAEP) was evaluated as a hearing screening test in 168 high-risk newborns. The BAEP was found to be a sensitive procedure for the early identification of hearing-impaired newborns. However, the yield of significant hearing abnormalities was less than predicted in other studies using BAEP. (Author/CL)

Maturation of long latency auditory evoked potentials in hearing children: systematic review.

PubMed

Silva, Liliane Aparecida Fagundes; Magliaro, Fernanda Cristina Leite; Carvalho, Ana Claudia Martinho de; Matas, Carla Gentile

2017-05-15

To analyze how Auditory Long Latency Evoked Potentials (LLAEP) change according to age in children population through a systematic literature review. After formulation of the research question, a bibliographic survey was done in five data bases with the following descriptors: Electrophysiology (Eletrofisiologia), Auditory Evoked Potentials (Potenciais Evocados Auditivos), Child (Criança), Neuronal Plasticity (Plasticidade Neuronal) and Audiology (Audiologia). Level 1 evidence articles, published between 1995 and 2015 in Brazilian Portuguese or English language. Aspects related to emergence, morphology and latency of P1, N1, P2 and N2 components were analyzed. A total of 388 studies were found; however, only 21 studies contemplated the established criteria. P1 component is characterized as the most frequent component in young children, being observed around 100-150 ms, which tends to decrease as chronological age increases. The N2 component was shown to be the second most commonly observed component in children, being observed around 200-250 ms.. The other N1 and P2 components are less frequent and begin to be seen and recorded throughout the maturational process. The maturation of LLAEP occurs gradually, and the emergence of P1, N1, P2 and N2 components as well as their latency values are variable in childhood. P1 and N2 components are the most observed and described in pediatric population. The diversity of protocols makes the comparison between studies difficult.

Peripheral generators of the vestibular evoked potentials (VsEPs) in the chick.

PubMed

Weisleder, P; Jones, T A; Rubel, E W

1990-10-01

Electrophysiological activity in response to linear acceleration stimuli was recorded from young chickens by means of subcutaneous electrodes. This investigation had 2 purposes: (1) to establish the vestibular origin of the potentials; and (2) to investigate the contribution of each vestibular labyrinth to the response. The stimuli consisted of pulses of linear acceleration delivered by a mechanical vibrator (shaker). In the first set of experiments vestibular evoked potentials (VsEPs) were recorded prior to and 24 h after bilateral cochlea removal. In the second set of experiments responses were recorded before and after unilateral or bilateral intralabyrinthine injections of tetrodotoxin (TTX). Different groups of subjects were used for each experimental condition. The general morphology of the VsEPs was maintained after bilateral cochlea removal. Absolute latency of wave P2, the most prominent component of the response, was not significantly affected by the manipulation. Unilateral intralabyrinthine TTX injections consistently prolonged the latency and reduced the amplitude of wave P2. Following binaural TTX injections we were unable to elicit responses at the acceleration levels used in this study. The results from these experiments suggest that: (1) the activity recorded in response to linear acceleration stimuli is vestibular in origin; (2) when recorded from intact animals the evoked response is composed of activity from both vestibular systems; and (3) TTX consistently blocks the activity of the vestibular portion of the VIIIth cranial nerve.

Diminished n1 auditory evoked potentials to oddball stimuli in misophonia patients.

PubMed

Schröder, Arjan; van Diepen, Rosanne; Mazaheri, Ali; Petropoulos-Petalas, Diamantis; Soto de Amesti, Vicente; Vulink, Nienke; Denys, Damiaan

2014-01-01

Misophonia (hatred of sound) is a newly defined psychiatric condition in which ordinary human sounds, such as breathing and eating, trigger impulsive aggression. In the current study, we investigated if a dysfunction in the brain's early auditory processing system could be present in misophonia. We screened 20 patients with misophonia with the diagnostic criteria for misophonia, and 14 matched healthy controls without misophonia, and investigated any potential deficits in auditory processing of misophonia patients using auditory event-related potentials (ERPs) during an oddball task. Subjects watched a neutral silent movie while being presented a regular frequency of beep sounds in which oddball tones of 250 and 4000 Hz were randomly embedded in a stream of repeated 1000 Hz standard tones. We examined the P1, N1, and P2 components locked to the onset of the tones. For misophonia patients, the N1 peak evoked by the oddball tones had smaller mean peak amplitude than the control group. However, no significant differences were found in P1 and P2 components evoked by the oddball tones. There were no significant differences between the misophonia patients and their controls in any of the ERP components to the standard tones. The diminished N1 component to oddball tones in misophonia patients suggests an underlying neurobiological deficit in misophonia patients. This reduction might reflect a basic impairment in auditory processing in misophonia patients.

Diminished N1 Auditory Evoked Potentials to Oddball Stimuli in Misophonia Patients

PubMed Central

Schröder, Arjan; van Diepen, Rosanne; Mazaheri, Ali; Petropoulos-Petalas, Diamantis; Soto de Amesti, Vicente; Vulink, Nienke; Denys, Damiaan

2014-01-01

Misophonia (hatred of sound) is a newly defined psychiatric condition in which ordinary human sounds, such as breathing and eating, trigger impulsive aggression. In the current study, we investigated if a dysfunction in the brain’s early auditory processing system could be present in misophonia. We screened 20 patients with misophonia with the diagnostic criteria for misophonia, and 14 matched healthy controls without misophonia, and investigated any potential deficits in auditory processing of misophonia patients using auditory event-related potentials (ERPs) during an oddball task. Subjects watched a neutral silent movie while being presented a regular frequency of beep sounds in which oddball tones of 250 and 4000 Hz were randomly embedded in a stream of repeated 1000 Hz standard tones. We examined the P1, N1, and P2 components locked to the onset of the tones. For misophonia patients, the N1 peak evoked by the oddball tones had smaller mean peak amplitude than the control group. However, no significant differences were found in P1 and P2 components evoked by the oddball tones. There were no significant differences between the misophonia patients and their controls in any of the ERP components to the standard tones. The diminished N1 component to oddball tones in misophonia patients suggests an underlying neurobiological deficit in misophonia patients. This reduction might reflect a basic impairment in auditory processing in misophonia patients. PMID:24782731

Deep brain stimulation of the ventral hippocampus restores deficits in processing of auditory evoked potentials in a rodent developmental disruption model of schizophrenia.

PubMed

Ewing, Samuel G; Grace, Anthony A

2013-02-01

Existing antipsychotic drugs are most effective at treating the positive symptoms of schizophrenia but their relative efficacy is low and they are associated with considerable side effects. In this study deep brain stimulation of the ventral hippocampus was performed in a rodent model of schizophrenia (MAM-E17) in an attempt to alleviate one set of neurophysiological alterations observed in this disorder. Bipolar stimulating electrodes were fabricated and implanted, bilaterally, into the ventral hippocampus of rats. High frequency stimulation was delivered bilaterally via a custom-made stimulation device and both spectral analysis (power and coherence) of resting state local field potentials and amplitude of auditory evoked potential components during a standard inhibitory gating paradigm were examined. MAM rats exhibited alterations in specific components of the auditory evoked potential in the infralimbic cortex, the core of the nucleus accumbens, mediodorsal thalamic nucleus, and ventral hippocampus in the left hemisphere only. DBS was effective in reversing these evoked deficits in the infralimbic cortex and the mediodorsal thalamic nucleus of MAM-treated rats to levels similar to those observed in control animals. In contrast stimulation did not alter evoked potentials in control rats. No deficits or stimulation-induced alterations were observed in the prelimbic and orbitofrontal cortices, the shell of the nucleus accumbens or ventral tegmental area. These data indicate a normalization of deficits in generating auditory evoked potentials induced by a developmental disruption by acute high frequency, electrical stimulation of the ventral hippocampus. Copyright © 2012 Elsevier B.V. All rights reserved.

NASA Rat Acoustic Tolerance Test 1994-1995

NASA Technical Reports Server (NTRS)

Holley, Daniel C.; Mele, Gary D.; Naidu, Sujata

1996-01-01

The major objective of this Cooperative Agreement was to develop a noise level specification for laboratory rats in the Centrifuge Facility Specimen Chambers (Space Station Biological Research Project), and to validate the specification for 3 noise octave bands: center frequencies 8 kHz, 16, kHz, and 32 kHz. This has been accomplished. Objective measures were used to verify that the chronic noise exposure was not harmful to the animals from physiological and behavioral perspectives. These measures were defined in the Stress Assessment Battery Validation for the Rat Acoustic Tolerance Test. In addition, the effects of the chronic noise exposure on rat hearing was assessed by the Brainstem Auditory Evoked Potential Method (BAER).

Evoked potentials recorded during routine EEG predict outcome after perinatal asphyxia.

PubMed

Nevalainen, Päivi; Marchi, Viviana; Metsäranta, Marjo; Lönnqvist, Tuula; Toiviainen-Salo, Sanna; Vanhatalo, Sampsa; Lauronen, Leena

2017-07-01

To evaluate the added value of somatosensory (SEPs) and visual evoked potentials (VEPs) recorded simultaneously with routine EEG in early outcome prediction of newborns with hypoxic-ischemic encephalopathy under modern intensive care. We simultaneously recorded multichannel EEG, median nerve SEPs, and flash VEPs during the first few postnatal days in 50 term newborns with hypoxic-ischemic encephalopathy. EEG background was scored into five grades and the worst two grades were considered to indicate poor cerebral recovery. Evoked potentials were classified as absent or present. Clinical outcome was determined from the medical records at a median age of 21months. Unfavorable outcome included cerebral palsy, severe mental retardation, severe epilepsy, or death. The accuracy of outcome prediction was 98% with SEPs compared to 90% with EEG. EEG alone always predicted unfavorable outcome when it was inactive (n=9), and favorable outcome when it was normal or only mildly abnormal (n=17). However, newborns with moderate or severe EEG background abnormality could have either favorable or unfavorable outcome, which was correctly predicted by SEP in all but one newborn (accuracy in this subgroup 96%). Absent VEPs were always associated with an inactive EEG, and an unfavorable outcome. However, presence of VEPs did not guarantee a favorable outcome. SEPs accurately predict clinical outcomes in newborns with hypoxic-ischemic encephalopathy and improve the EEG-based prediction particularly in those newborns with severely or moderately abnormal EEG findings. SEPs should be added to routine EEG recordings for early bedside assessment of newborns with hypoxic-ischemic encephalopathy. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Management of subaxial cervical facet dislocation through anterior approach monitored by spinal cord evoked potential.

PubMed

Du, Wei; Wang, Cheng; Tan, Jiangwei; Shen, Binghua; Ni, Shuqin; Zheng, Yanping

2014-01-01

Retrospective case series. To discuss the clinical efficacy of anterior cervical surgery of decompression, reduction, stabilization, and fusion in treating subaxial cervical facet dislocation without spinal cord injury or with mild spinal cord injury monitored by spinal cord evoked potential. The optimal treatment of lower cervical facet dislocation has been controversial. Because of the risk of iatrogenic damage of neurological function, it is challenging for surgeons to manage the lower cervical facet dislocation without or with mild spinal cord injury. To avoid the risks, more secure strategy need to be designed. A retrospective study was performed on 17 cases of subaxial cervical facet dislocation without spinal cord injury or with mild spinal cord injury treated by anterior cervical surgery under spinal cord evoked potential monitor from January 2008 to June 2012. There were 12 males, 5 females, with a mean age of 40.1 years (from 21 to 73 yr). Dislocation sites: 1 in C3-C4, 2 in C4-C5, 6 in C5-C6, 8 in C6-C7; 10 cases with unilateral cervical facet dislocation, 7 cases with bilateral dislocation. Thirteen patients were preoperatively classified as grade D and 4 as E according to Frankel standard. All patients were followed up for average of 16 months. All operations were completed successfully. Postoperative radiographs showed that the sequence and curvature of the cervical spine were well recovered. And, evidence of intervertebral fusion was observed at 3 months in all cases. No redislocation or symptoms of spinal cord injury occurred. Thirteen cases with mild spinal cord injury recovered at 1 month after operation. Anterior cervical surgery of decompression, reduction, stabilization, and fusion monitored by spinal cord evoked potential is an effective and safe method for treatment of subaxial cervical facet dislocation without or with mild spinal cord injury. 4.

Deconvolution of the vestibular evoked myogenic potential.

PubMed

Lütkenhöner, Bernd; Basel, Türker

2012-02-07

The vestibular evoked myogenic potential (VEMP) and the associated variance modulation can be understood by a convolution model. Two functions of time are incorporated into the model: the motor unit action potential (MUAP) of an average motor unit, and the temporal modulation of the MUAP rate of all contributing motor units, briefly called rate modulation. The latter is the function of interest, whereas the MUAP acts as a filter that distorts the information contained in the measured data. Here, it is shown how to recover the rate modulation by undoing the filtering using a deconvolution approach. The key aspects of our deconvolution algorithm are as follows: (1) the rate modulation is described in terms of just a few parameters; (2) the MUAP is calculated by Wiener deconvolution of the VEMP with the rate modulation; (3) the model parameters are optimized using a figure-of-merit function where the most important term quantifies the difference between measured and model-predicted variance modulation. The effectiveness of the algorithm is demonstrated with simulated data. An analysis of real data confirms the view that there are basically two components, which roughly correspond to the waves p13-n23 and n34-p44 of the VEMP. The rate modulation corresponding to the first, inhibitory component is much stronger than that corresponding to the second, excitatory component. But the latter is more extended so that the two modulations have almost the same equivalent rectangular duration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of User Interaction with a Brain-Computer Interface Based on Steady-State Visually Evoked Potentials: Case Study of a Game

PubMed Central

de Carvalho, Sarah Negreiros; Costa, Thiago Bulhões da Silva; Attux, Romis; Hornung, Heiko Horst; Arantes, Dalton Soares

2018-01-01

This paper presents a systematic analysis of a game controlled by a Brain-Computer Interface (BCI) based on Steady-State Visually Evoked Potentials (SSVEP). The objective is to understand BCI systems from the Human-Computer Interface (HCI) point of view, by observing how the users interact with the game and evaluating how the interface elements influence the system performance. The interactions of 30 volunteers with our computer game, named “Get Coins,” through a BCI based on SSVEP, have generated a database of brain signals and the corresponding responses to a questionnaire about various perceptual parameters, such as visual stimulation, acoustic feedback, background music, visual contrast, and visual fatigue. Each one of the volunteers played one match using the keyboard and four matches using the BCI, for comparison. In all matches using the BCI, the volunteers achieved the goals of the game. Eight of them achieved a perfect score in at least one of the four matches, showing the feasibility of the direct communication between the brain and the computer. Despite this successful experiment, adaptations and improvements should be implemented to make this innovative technology accessible to the end user. PMID:29849549

Analysis of User Interaction with a Brain-Computer Interface Based on Steady-State Visually Evoked Potentials: Case Study of a Game.

PubMed

Leite, Harlei Miguel de Arruda; de Carvalho, Sarah Negreiros; Costa, Thiago Bulhões da Silva; Attux, Romis; Hornung, Heiko Horst; Arantes, Dalton Soares

2018-01-01

This paper presents a systematic analysis of a game controlled by a Brain-Computer Interface (BCI) based on Steady-State Visually Evoked Potentials (SSVEP). The objective is to understand BCI systems from the Human-Computer Interface (HCI) point of view, by observing how the users interact with the game and evaluating how the interface elements influence the system performance. The interactions of 30 volunteers with our computer game, named "Get Coins," through a BCI based on SSVEP, have generated a database of brain signals and the corresponding responses to a questionnaire about various perceptual parameters, such as visual stimulation, acoustic feedback, background music, visual contrast, and visual fatigue. Each one of the volunteers played one match using the keyboard and four matches using the BCI, for comparison. In all matches using the BCI, the volunteers achieved the goals of the game. Eight of them achieved a perfect score in at least one of the four matches, showing the feasibility of the direct communication between the brain and the computer. Despite this successful experiment, adaptations and improvements should be implemented to make this innovative technology accessible to the end user.

Auditory brain stem response and cortical evoked potentials in children with type 1 diabetes mellitus.

PubMed

Radwan, Heba Mohammed; El-Gharib, Amani Mohamed; Erfan, Adel Ali; Emara, Afaf Ahmad

2017-05-01

Delay in ABR and CAEPs wave latencies in children with type 1DM indicates that there is abnormality in the neural conduction in DM patients. The duration of DM has greater effect on auditory function than the control of DM. Diabetes mellitus (DM) is a common endocrine and metabolic disorder. Evoked potentials offer the possibility to perform a functional evaluation of neural pathways in the central nervous system. To investigate the effect of type 1 diabetes mellitus (T1DM) on auditory brain stem response (ABR) and cortical evoked potentials (CAEPs). This study included two groups: a control group (GI), which consisted of 20 healthy children with normal peripheral hearing, and a study group (GII), which consisted of 30 children with type I DM. Basic audiological evaluation, ABR, and CAEPs were done in both groups. Delayed absolute latencies of ABR and CAEPs waves were found. Amplitudes showed no significant difference between both groups. Positive correlation was found between ABR wave latencies and duration of DM. No correlation was found between ABR, CAEPs, and glycated hemoglobin.

Pressure potential and stability analysis in an acoustical noncontact transportation

NASA Astrophysics Data System (ADS)

Li, J.; Liu, C. J.; Zhang, W. J.

2017-01-01

Near field acoustic traveling wave is one of the most popular principles in noncontact manipulations and transportations. The stability behavior is a key factor in the industrial applications of acoustical noncontact transportation. We present here an in-depth analysis of the transportation stability of a planar object levitated in near field acoustic traveling waves. To more accurately describe the pressure distributions on the radiation surface, a 3D nonlinear traveling wave model is presented. A closed form solution is derived based on the pressure potential to quantitatively calculate the restoring forces and moments under small disturbances. The physical explanations of the effects of fluid inertia and the effects of non-uniform pressure distributions are provided in detail. It is found that a vibration rail with tapered cross section provides more stable transportation than a rail with rectangular cross section. The present study sheds light on the issue of quantitative evaluation of stability in acoustic traveling waves and proposes three main factors that influence the stability: (a) vibration shape, (b) pressure distribution and (c) restoring force/moment. It helps to provide a better understanding of the physics behind the near field acoustic transportation and provide useful design and optimization tools for industrial applications.

Activation of cannabinoid CB1 receptors modulates evoked action potentials in rat retinal ganglion cells.

PubMed

Jiang, Shu-Xia; Li, Qian; Wang, Xiao-Han; Li, Fang; Wang, Zhong-Feng

2013-08-25

Activation of cannabinoid CB1 receptors (CB1Rs) regulates a variety of physiological functions in the vertebrate retina through modulating various types of ion channels. The aim of the present study was to investigate the effects of this receptor on cell excitability of rat retinal ganglion cells (RGCs) in retinal slices using whole-cell patch-clamp techniques. The results showed that under current-clamped condition perfusing WIN55212-2 (WIN, 5 μmol/L), a CB1R agonist, did not significantly change the spontaneous firing frequency and resting membrane potential of RGCs. In the presence of cocktail synaptic blockers, including excitatory postsynaptic receptor blockers CNQX and D-APV, and inhibitory receptor blockers bicuculline and strychnine, perfusion of WIN (5 μmol/L) hardly changed the frequencies of evoked action potentials by a series of positive current injection (from +10 to +100 pA). Phase-plane plot analysis showed that both average threshold voltage for triggering action potential and delay time to reach threshold voltage were not affected by WIN. However, WIN significantly decreased +dV/dtmax and -dV/dtmax of action potentials, suggestive of reduced rising and descending velocities of action potentials. The effects of WIN were reversed by co-application of SR141716, a CB1R selective antagonist. Moreover, WIN did not influence resting membrane potential of RGCs with synaptic inputs being blocked. These results suggest that activation of CB1Rs may regulate intrinsic excitability of rat RGCs through modulating evoked action potentials.

[Evoked potentials N200/P300 disorders and clinical phenotype in Cuban families with paranoid schizophrenia: a family-based association study].

PubMed

Guerra López, Seidel; Martín Reyes, Migdyrai; Pedroso Rodríguez, María de Los Ángeles; Reyes Berazain, Adnelys; Mendoza Quiñones, Raúl; Bravo Collazo, Tania Martha; Días de Villarvilla, Thais; Machado Cano, María Julia; Bobés León, María Antonieta

2015-04-01

N200 and P300 event-related evoked potentials provide sensitive measurements of sensory and cognitive function and have been used to study information processing in patients with schizophrenia and their unaffected first-degree relatives. Reduced amplitude and increased latency of N200 and P300 potentials have been consistently reported in schizophrenia. Thus, event-related evoked potentials abnormalities are promising possible biological markers for genetic vulnerability to schizophrenia. To assess the association of changes in latency, amplitude and topographic distribution of potentials N200 and P300 of patients with paranoid schizophrenia and their healthy first-degree relatives, in families with schizophrenia multiplex. We measured latency and amplitude of the N200 and P300 component of evoked potentials using an auditory odd-ball paradigm in 25 schizophrenic patients (probands) from 60 families multiply affected with paranoid schizophrenia, 23 of their non-schizophrenic first-degree relatives and 25 unrelated healthy controls, through a study of family association. Schizophrenic patients and their relatives showed significant latency prolongation and amplitude reduction of the N200 and P300 waves compared to controls. Left-temporal as compared to right-temporal N200 and P300 were significantly smaller in schizophrenic patients and their non-schizophrenic first-degree relatives than in controls. Our results suggest that event-related evoked potentials abnormalities may serve as markers of genetic vulnerability in schizophrenia. Confirming results of other researchers, this present study suggests that latency prolongation and amplitude reduction of the N200 and P300 waves and an altered topography at temporal sites may be a trait “marker” of paranoid schizophrenia.

Serial auditory-evoked potentials in the diagnosis and monitoring of a child with Landau-Kleffner syndrome.

PubMed

Plyler, Erin; Harkrider, Ashley W

2013-01-01

A boy, aged 2 1/2 yr, experienced sudden deterioration of speech and language abilities. He saw multiple medical professionals across 2 yr. By almost 5 yr, his vocabulary diminished from 50 words to 4, and he was referred to our speech and hearing center. The purpose of this study was to heighten awareness of Landau-Kleffner syndrome (LKS) and emphasize the importance of an objective test battery that includes serial auditory-evoked potentials (AEPs) to audiologists who often are on the front lines of diagnosis and treatment delivery when faced with a child experiencing unexplained loss of the use of speech and language. Clinical report. Interview revealed a family history of seizure disorder. Normal social behaviors were observed. Acoustic reflexes and otoacoustic emissions were consistent with normal peripheral auditory function. The child could not complete behavioral audiometric testing or auditory processing tests, so serial AEPs were used to examine central nervous system function. Normal auditory brainstem responses, a replicable Na and absent Pa of the middle latency responses, and abnormal slow cortical potentials suggested dysfunction of auditory processing at the cortical level. The child was referred to a neurologist, who confirmed LKS. At age 7 1/2 yr, after 2 1/2 yr of antiepileptic medications, electroencephalographic (EEG) and audiometric measures normalized. Presently, the child communicates manually with limited use of oral information. Audiologists often are one of the first professionals to assess children with loss of speech and language of unknown origin. Objective, noninvasive, serial AEPs are a simple and valuable addition to the central audiometric test battery when evaluating a child with speech and language regression. The inclusion of these tests will markedly increase the chance for early and accurate referral, diagnosis, and monitoring of a child with LKS which is imperative for a positive prognosis. American Academy of Audiology.

Vestibular-Evoked Myogenic Potentials in Bilateral Vestibulopathy

PubMed Central

Rosengren, Sally M.; Welgampola, Miriam S.; Taylor, Rachael L.

2018-01-01

Bilateral vestibulopathy (BVP) is a chronic condition in which patients have a reduction or absence of vestibular function in both ears. BVP is characterized by bilateral reduction of horizontal canal responses; however, there is increasing evidence that otolith function can also be affected. Cervical and ocular vestibular-evoked myogenic potentials (cVEMPs/oVEMPs) are relatively new tests of otolith function that can be used to test the saccule and utricle of both ears independently. Studies to date show that cVEMPs and oVEMPs are often small or absent in BVP but are in the normal range in a significant proportion of patients. The variability in otolith function is partly due to the heterogeneous nature of BVP but is also due to false negative and positive responses that occur because of the large range of normal VEMP amplitudes. Due to their variability, VEMPs are not part of the diagnosis of BVP; however, they are helpful complementary tests that can provide information about the extent of disease within the labyrinth. This article is a review of the use of VEMPs in BVP, summarizing the available data on VEMP abnormalities in patients and discussing the limitations of VEMPs in diagnosing bilateral loss of otolith function. PMID:29719527

Frontal auditory evoked potentials and augmenting-reducing.

PubMed

Bruneau, N; Roux, S; Garreau, B; Lelord, G

1985-09-01

Auditory evoked potentials (AEPs) to tones (750 Hz--200 msec) ranging from 50 to 80 dB SPL were studied at Cz and Fz leads in 29 normal adults (15 males) ranging in age from 20 to 22. Peak-to-trough amplitudes were measured for the P1-N1 and the N1-P2 wave forms as well as baseline (500 msec prestimulus)-to-peak amplitudes for each component, i.e., P1, N1 and P2. Amplitudes were examined as a function of intensity and electrode location. Cz-Fz amplitude differences increased with increasing stimulus intensity, the differentiating peak being the N1 component. An overall reducing phenomenon was found at Fz in the 70-80 dB range whereas an augmenting effect was observed at Cz for these intensities. The augmenting/reducing groups defined by analysis of individual amplitude-intensity patterns were different whether we considered Fz or Cz results: Fz reducers were more numerous than Cz reducers. These results on prominent reducing at the frontal level were examined in relation to the data concerning the modulatory function of the frontal cortex on auditory EPs. Implications were drawn for the role of the frontal cortex in cortical augmenting-reducing.

Synaptic potentials in respiratory neurones during evoked phase switching after NMDA receptor blockade in the cat

PubMed Central

Pierrefiche, O; Haji, A; Foutz, A S; Takeda, R; Champagnat, J; Denavit-Saubié, M

1998-01-01

Blockade of NMDA receptors by dizocilpine impairs the inspiratory off-switch (IOS) of central origin but not the IOS evoked by stimulation of sensory afferents. To investigate whether this difference was due to the effects of different patterns of synaptic interactions on respiratory neurones, we stimulated electrically the superior laryngeal nerve (SLN) or vagus nerve in decerebrate cats before and after i.v. administration of dizocilpine, whilst recording intracellularly. Phrenic nerve responses to ipsilateral SLN or vagal stimulation were: at mid-inspiration, a transient inhibition often followed by a brief burst of activity; at late inspiration, an IOS; and at mid-expiration, a late burst of activity. In all neurones (n = 16), SLN stimulation at mid-inspiration evoked an early EPSP during phase 1 (latency to the arrest of phrenic nerve activity), followed by an IPSP in inspiratory (I) neurones (n = 8) and by a wave of EPSPs in post-inspiratory (PI) neurones (n = 8) during phase 2 (inhibition of phrenic activity). An EPSP in I neurones and an IPSP in PI neurones occurred during phase 3 (brief phrenic burst) following phase 2. Evoked IOS was associated with a fast (phase 1) activation of PI neurones, whereas during spontaneous IOS, a progressive (30-50 ms) depolarization of PI neurones preceded the arrest of phrenic activity. Phase 3 PSPs were similar to those occurring during the burst of activity seen at the start of spontaneous inspiration. Dizocilpine did not suppress the evoked phrenic inhibition and the late burst of activity. The shapes and timing of the evoked PSPs and the changes in membrane potential in I and PI neurones during the phase transition were not altered. We hypothesize that afferent sensory pathways not requiring NMDA receptors (1) terminate inspiration through a premature activation of PI neurones, and (2) evoke a late burst of phrenic activity which might be the first stage of the inspiratory on-switch. PMID:9508816

High-frequency combination coding-based steady-state visual evoked potential for brain computer interface

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

Zhang, Feng; Zhang, Xin; Xie, Jun

2015-03-10

This study presents a new steady-state visual evoked potential (SSVEP) paradigm for brain computer interface (BCI) systems. The goal of this study is to increase the number of targets using fewer stimulation high frequencies, with diminishing subject’s fatigue and reducing the risk of photosensitive epileptic seizures. The new paradigm is High-Frequency Combination Coding-Based High-Frequency Steady-State Visual Evoked Potential (HFCC-SSVEP).Firstly, we studied SSVEP high frequency(beyond 25 Hz)response of SSVEP, whose paradigm is presented on the LED. The SNR (Signal to Noise Ratio) of high frequency(beyond 40 Hz) response is very low, which is been unable to be distinguished through the traditional analysis method;more » Secondly we investigated the HFCC-SSVEP response (beyond 25 Hz) for 3 frequencies (25Hz, 33.33Hz, and 40Hz), HFCC-SSVEP produces n{sup n} with n high stimulation frequencies through Frequence Combination Code. Further, Animproved Hilbert-huang transform (IHHT)-based variable frequency EEG feature extraction method and a local spectrum extreme target identification algorithmare adopted to extract time-frequency feature of the proposed HFCC-SSVEP response.Linear predictions and fixed sifting (iterating) 10 time is used to overcome the shortage of end effect and stopping criterion,generalized zero-crossing (GZC) is used to compute the instantaneous frequency of the proposed SSVEP respondent signals, the improved HHT-based feature extraction method for the proposed SSVEP paradigm in this study increases recognition efficiency, so as to improve ITR and to increase the stability of the BCI system. what is more, SSVEPs evoked by high-frequency stimuli (beyond 25Hz) minimally diminish subject’s fatigue and prevent safety hazards linked to photo-induced epileptic seizures, So as to ensure the system efficiency and undamaging.This study tests three subjects in order to verify the feasibility of the proposed method.« less

Mapping human brain networks with cortico-cortical evoked potentials

PubMed Central

Keller, Corey J.; Honey, Christopher J.; Mégevand, Pierre; Entz, Laszlo; Ulbert, Istvan; Mehta, Ashesh D.

2014-01-01

The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex. PMID:25180306

Pericellular Ca2+ recycling potentiates thrombin-evoked Ca2+ signals in human platelets

PubMed Central

Sage, Stewart O; Pugh, Nicholas; Farndale, Richard W; Harper, Alan G S

2013-01-01

We have previously demonstrated that Na+/Ca2+ exchangers (NCXs) potentiate Ca2+ signaling evoked by thapsigargin in human platelets, via their ability to modulate the secretion of autocoids from dense granules. This link was confirmed in platelets stimulated with the physiological agonist, thrombin, and experiments were performed to examine how Ca2+ removal by the NCX modulates platelet dense granule secretion. In cells loaded with the near-membrane indicator FFP-18, thrombin stimulation was observed to elicit an NCX-dependent accumulation of Ca2+ in a pericellular region around the platelets. To test whether this pericellular Ca2+ accumulation might be responsible for the influence of NCXs over platelet function, platelets were exposed to fast Ca2+ chelators or had their glycocalyx removed. Both manipulations of the pericellular Ca2+ rise reduced thrombin-evoked Ca2+ signals and dense granule secretion. Blocking Ca2+-permeable ion channels had a similar effect, suggesting that Ca2+ exported into the pericellular region is able to recycle back into the platelet cytosol. Single cell imaging with extracellular Fluo-4 indicated that thrombin-evoked rises in extracellular [Ca2+] occurred within the boundary described by the cell surface, suggesting their presence within the open canalicular system (OCS). FFP-18 fluorescence was similarly distributed. These data suggest that upon thrombin stimulation, NCX activity creates a rise in [Ca2+] within the pericellular region of the platelet from where it recycles back into the platelet cytosol, acting to both accelerate dense granule secretion and maintain the initial rise in cytosolic [Ca2+]. PMID:24303163

Sensory-evoked LTP driven by dendritic plateau potentials in vivo.

PubMed

Gambino, Frédéric; Pagès, Stéphane; Kehayas, Vassilis; Baptista, Daniela; Tatti, Roberta; Carleton, Alan; Holtmaat, Anthony

2014-11-06

Long-term synaptic potentiation (LTP) is thought to be a key process in cortical synaptic network plasticity and memory formation. Hebbian forms of LTP depend on strong postsynaptic depolarization, which in many models is generated by action potentials that propagate back from the soma into dendrites. However, local dendritic depolarization has been shown to mediate these forms of LTP as well. As pyramidal cells in supragranular layers of the somatosensory cortex spike infrequently, it is unclear which of the two mechanisms prevails for those cells in vivo. Using whole-cell recordings in the mouse somatosensory cortex in vivo, we demonstrate that rhythmic sensory whisker stimulation efficiently induces synaptic LTP in layer 2/3 (L2/3) pyramidal cells in the absence of somatic spikes. The induction of LTP depended on the occurrence of NMDAR (N-methyl-d-aspartate receptor)-mediated long-lasting depolarizations, which bear similarities to dendritic plateau potentials. In addition, we show that whisker stimuli recruit synaptic networks that originate from the posteromedial complex of the thalamus (POm). Photostimulation of channelrhodopsin-2 expressing POm neurons generated NMDAR-mediated plateau potentials, whereas the inhibition of POm activity during rhythmic whisker stimulation suppressed the generation of those potentials and prevented whisker-evoked LTP. Taken together, our data provide evidence for sensory-driven synaptic LTP in vivo, in the absence of somatic spiking. Instead, LTP is mediated by plateau potentials that are generated through the cooperative activity of lemniscal and paralemniscal synaptic circuitry.

Auditory Evoked Potentials from the Frog Eighth Nerve

DTIC Science & Technology

1989-09-01

superior olivary nucleus 6, 10-100 ms in torus semicircularis’ 2,4’ 14, 1618, 30-120 ms in thalamus 7’ 1,13,14, and greater than 30 ms in telencephalon 12...899. 12 Mudry, K.M. and Capranica, R.R., Evoked auditory activity within the telencephalon of the bullfrog (Rana catesbeiana), Brain Res., 182 (1980

Mismatch negativity evoked by the McGurk-MacDonald effect: a phonetic representation within short-term memory.

PubMed

Colin, C; Radeau, M; Soquet, A; Demolin, D; Colin, F; Deltenre, P

2002-04-01

The McGurk-MacDonald illusory percept is obtained by dubbing an incongruent articulatory movement on an auditory phoneme. This type of audiovisual speech perception contributes to the assessment of theories of speech perception. The mismatch negativity (MMN) reflects the detection of a deviant stimulus within the auditory short-term memory and besides an acoustic component, possesses, under certain conditions, a phonetic one. The present study assessed the existence of an MMN evoked by McGurk-MacDonald percepts elicited by audiovisual stimuli with constant auditory components. Cortical evoked potentials were recorded using the oddball paradigm on 8 adults in 3 experimental conditions: auditory alone, visual alone and audiovisual stimulation. Obtaining illusory percepts was confirmed in an additional psychophysical condition. The auditory deviant syllables and the audiovisual incongruent syllables elicited a significant MMN at Fz. In the visual condition, no negativity was observed either at Fz, or at O(z). An MMN can be evoked by visual articulatory deviants, provided they are presented in a suitable auditory context leading to a phonetically significant interaction. The recording of an MMN elicited by illusory McGurk percepts suggests that audiovisual integration mechanisms in speech take place rather early during the perceptual processes.

Bilateral somatosensory evoked potentials following intermittent theta-burst repetitive transcranial magnetic stimulation.

PubMed

Premji, Azra; Ziluk, Angela; Nelson, Aimee J

2010-08-05

Intermittent theta-burst stimulation (iTBS) is a form of repetitive transcranial magnetic stimulation that may alter cortical excitability in the primary somatosensory cortex (SI). The present study investigated the effects of iTBS on subcortical and early cortical somatosensory evoked potentials (SEPs) recorded over left, iTBS stimulated SI and the right-hemisphere non-stimulated SI. SEPs were recorded before and at 5, 15, and 25 minutes following iTBS. Compared to pre-iTBS, the amplitude of cortical potential N20/P25 was significantly increased for 5 minutes from non-stimulated SI and for 15 to 25 minutes from stimulated SI. Subcortical potentials recorded bilaterally remained unaltered following iTBS. We conclude that iTBS increases the cortical excitability of SI bilaterally and does not alter thalamocortical afferent input to SI. ITBS may provide one avenue to induce cortical plasticity in the somatosensory cortex.

Effects of Long-Term Musical Training on Cortical Evoked Auditory Potentials

PubMed Central

Brown, Carolyn J.; Jeon, Eun-Kyung; Driscoll, Virginia; Mussoi, Bruna; Deshpande, Shruti Balvalli; Gfeller, Kate; Abbas, Paul

2016-01-01

Objective Evidence suggests that musicians, as a group, have superior frequency resolution abilities when compared to non-musicians. It is possible to assess auditory discrimination using either behavioral or electrophysiologic methods. The purpose of this study was to determine if the auditory change complex (ACC) is sensitive enough to reflect the differences in spectral processing exhibited by musicians and non-musicians. Design Twenty individuals (10 musicians and 10 non-musicians) participated in this study. Pitch and spectral ripple discrimination were assessed using both behavioral and electrophysiologic methods. Behavioral measures were obtained using a standard three interval, forced choice procedure and the ACC was recorded and used as an objective (i.e. non-behavioral) measure of discrimination between two auditory signals. The same stimuli were used for both psychophysical and electrophysiologic testing. Results As a group, musicians were able to detect smaller changes in pitch than non-musicians. They also were able to detect a shift in the position of the peaks and valleys in a ripple noise stimulus at higher ripple densities than non-musicians. ACC responses recorded from musicians were larger than those recorded from non-musicians when the amplitude of the ACC response was normalized to the amplitude of the onset response in each stimulus pair. Visual detection thresholds derived from the evoked potential data were better for musicians than non-musicians regardless of whether the task was discrimination of musical pitch or detection of a change in the frequency spectrum of the rippled noise stimuli. Behavioral measures of discrimination were generally more sensitive than the electrophysiologic measures; however, the two metrics were correlated. Conclusions Perhaps as a result of extensive training, musicians are better able to discriminate spectrally complex acoustic signals than non-musicians. Those differences are evident not only in perceptual

The P50 auditory evoked potential in violent and non-violent patients with schizophrenia.

PubMed

Fresán, Ana; Apiquian, Rogelio; García-Anaya, María; de la Fuente-Sandoval, Camilo; Nicolini, Humberto; Graff-Guerrero, Ariel

2007-12-01

Emotionally driven violence is facilitated by increased arousal. It may be a consequence of an information-processing deficit and the cognitive attributions for the stimuli given by the subject. The aim of this study was to compare the P50 evoked potential responses of violent patients with schizophrenia with non-violent patients with schizophrenia and healthy controls. Patients were classified into violent and non-violent in accordance to the Overt Aggression Scale. P50 auditory evoked potentials of 32 unmedicated patients with schizophrenia (violent=14, non-violent=18) and 17 healthy controls were recorded during five runs of 30 click pairs. Healthy controls exhibited a lower S2/S1 ratio when compared to violent (p<0.001) and non-violent (p=0.04) patients. Using a cutoff point of 0.50 for S2/S1 ratio to define abnormal gating a significant proportion of violent patients did not show P50 suppression (71.4%) in comparison to non-violent patients (38.9%) and healthy controls (23.5%) (p=0.02). Violent behavior in patients with schizophrenia could be associated with a disturbed information sensory gating. Violence in patients with schizophrenia may be facilitated by an increased arousal which may in turn be the result of an information-processing deficit.

[Forensic application of brainstem auditory evoked potential in patients with brain concussion].

PubMed

Zheng, Xing-Bin; Li, Sheng-Yan; Huang, Si-Xing; Ma, Ke-Xin

2008-12-01

To investigate changes of brainstem auditory evoked potential (BAEP) in patients with brain concussion. Nineteen patients with brain concussion were studied with BAEP examination. The data was compared to the healthy persons reported in literatures. The abnormal rate of BAEP for patients with brain concussion was 89.5%. There was a statistically significant difference between the abnormal rate of patients and that of healthy persons (P<0.05). The abnormal rate of BAEP in the brainstem pathway for patients with brain concussion was 73.7%, indicating dysfunction of the brainstem in those patients. BAEP might be helpful in forensic diagnosis of brain concussion.

The developmental effects of extremely low frequency electric fields on visual and somatosensory evoked potentials in adult rats.

PubMed

Gok, Deniz Kantar; Akpinar, Deniz; Hidisoglu, Enis; Ozen, Sukru; Agar, Aysel; Yargicoglu, Piraye

2016-01-01

The purpose of our study was to investigate the developmental effects of extremely low frequency electric fields (ELF-EFs) on visual evoked potentials (VEPs) and somatosensory-evoked potentials (SEPs) and to examine the relationship between lipid peroxidation and changes of these potentials. In this context, thiobarbituric acid reactive substances (TBARS) levels were determined as an indicator of lipid peroxidation. Wistar albino female rats were divided into four groups; Control (C), gestational (prenatal) exposure (Pr), gestational+ postnatal exposure (PP) and postnatal exposure (Po) groups. Pregnant rats of Pr and PP groups were exposed to 50 Hz electric field (EF) (12 kV/m; 1 h/day), while those of C and Po groups were placed in an inactive system during pregnancy. Following parturition, rats of PP and Po groups were exposed to ELF-EFs whereas rats of C and Pr groups were kept under the same experimental conditions without being exposed to any EF during 68 days. On postnatal day 90, rats were prepared for VEP and SEP recordings. The latencies of VEP components in all experimental groups were significantly prolonged versus C group. For SEPs, all components of PP group, P2, N2 components of Pr group and P1, P2, N2 components of Po group were delayed versus C group. As brain TBARS levels were significantly increased in Pr and Po groups, retina TBARS levels were significantly elevated in all experimental groups versus C group. In conclusion, alterations seen in evoked potentials, at least partly, could be explained by lipid peroxidation in the retina and brain.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study.

PubMed

Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Raimundo, Jeziela Cristina; Bento, Ricardo Ferreira; Matas, Carla Gentile

2018-02-19

The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing. Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points. The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use. Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users.

Monitoring auditory cortical plasticity in hearing aid users with long latency auditory evoked potentials: a longitudinal study

PubMed Central

Leite, Renata Aparecida; Magliaro, Fernanda Cristina Leite; Raimundo, Jeziela Cristina; Bento, Ricardo Ferreira; Matas, Carla Gentile

2018-01-01

OBJECTIVE: The objective of this study was to compare long-latency auditory evoked potentials before and after hearing aid fittings in children with sensorineural hearing loss compared with age-matched children with normal hearing. METHODS: Thirty-two subjects of both genders aged 7 to 12 years participated in this study and were divided into two groups as follows: 14 children with normal hearing were assigned to the control group (mean age 9 years and 8 months), and 18 children with mild to moderate symmetrical bilateral sensorineural hearing loss were assigned to the study group (mean age 9 years and 2 months). The children underwent tympanometry, pure tone and speech audiometry and long-latency auditory evoked potential testing with speech and tone burst stimuli. The groups were assessed at three time points. RESULTS: The study group had a lower percentage of positive responses, lower P1-N1 and P2-N2 amplitudes (speech and tone burst), and increased latencies for the P1 and P300 components following the tone burst stimuli. They also showed improvements in long-latency auditory evoked potentials (with regard to both the amplitude and presence of responses) after hearing aid use. CONCLUSIONS: Alterations in the central auditory pathways can be identified using P1-N1 and P2-N2 amplitude components, and the presence of these components increases after a short period of auditory stimulation (hearing aid use). These findings emphasize the importance of using these amplitude components to monitor the neuroplasticity of the central auditory nervous system in hearing aid users. PMID:29466495

Asymmetric vestibular evoked myogenic potentials in unilateral Menière patients

PubMed Central

Wit, H. P.

2010-01-01

Vestibular evoked myogenic potentials (VEMPs) were measured in 22 unilateral Menière patients with monaural and binaural stimulation with 250 and 500 Hz tone bursts. For all measurement situations significantly lower VEMP amplitudes were on average measured at the affected side compared to the unaffected side. Unilateral Menière patients have, in contrast to normal subjects, asymmetric VEMPs, indicating a permanently affected vestibular (most likely otolith) system at the side of hearing loss. The diagnostic value of VEMP amplitude asymmetry measurement in individual patients is low, because of the large overlap of the VEMP amplitude asymmetry range for unilateral Menière patients with that for normal subjects. PMID:20665043

Analysis of wave III of brain stem auditory evoked potential waveforms during microvascular decompression of cranial nerve VII for hemifacial spasm.

PubMed

Thirumala, Parthasarathy D; Krishnaiah, Balaji; Crammond, Donald J; Habeych, Miguel E; Balzer, Jeffrey R

2014-04-01

Intraoperative monitoring of brain stem auditory evoked potential during microvascular decompression (MVD) prevent hearing loss (HL). Previous studies have shown that changes in wave III (wIII) are an early and sensitive sign of auditory nerve injury. To evaluate the changes of amplitude and latency of wIII of brain stem auditory evoked potential during MVD and its association with postoperative HL. Hearing loss was classified by American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) criteria, based on changes in pure tone audiometry and speech discrimination score. Retrospective analysis of wIII in patients who underwent intraoperative monitoring with brain stem auditory evoked potential during MVD was performed. A univariate logistic regression analysis was performed on independent variables amplitude of wIII and latency of wIII at change max and On-Skin, or a final recording at the time of skin closure. A further analysis for the same variables was performed adjusting for the loss of wave. The latency of wIII was not found to be significantly different between groups I and II. The amplitude of wIII was significantly decreased in the group with HL. Regression analysis did not find any increased odds of HL with changes in the amplitude of wIII. Changes in wave III did not increase the odds of HL in patients who underwent brain stem auditory evoked potential s during MVD. This information might be valuable to evaluate the value of wIII as an alarm criterion during MVD to prevent HL.

Acoustic tests of a 15.2 centimeter-diameter potential flow convergent nozzle

NASA Technical Reports Server (NTRS)

Karchmer, A. M.; Dorsch, R. G.; Friedman, R.

1974-01-01

An experimental investigation of the jet noise radiated to the far field from a 15.2-cm-diam potential flow convergent nozzle has been conducted. Tests were made with unheated airflow over a range of subsonic nozzle exhaust velocities from 62 to 310m/sec. Mean and turbulent velocity measurements in the flow field of the nozzle exhaust indicated no apparent flow anomalies. Acoustic measurements yielded data uncontaminated by internal and/or background noise to velocities as low as 152m/sec. Finally, no significantly different acoustic characteristics between the potential flow nozzle and simple convergent nozzles were found.

A new method for registration of kinesthetic evoked potentials for studies of proprioceptive sensitivity in normal subjects and patients with organic lesions in the brain.

PubMed

Gordeev, S A; Voronin, S G

2015-01-01

The proprioceptive sensitivity of healthy volunteers and convalescents after acute cerebrovascular episodes was studied by a new neurophysiological method for registration of kinesthetic evoked potentials emerging in response to passive 50(o) bending of the hand in the wrist joint with the angular acceleration of 350 rad/sec(2). Kinesthetic evoked potentials were recorded above the somatosensory cortex projection areas in the hemispheres contra- and ipsilateral to the stimulated limb. The patients exhibited significantly longer latencies and lesser amplitudes of the early components of response in the involved hemisphere in comparison with normal subjects. The method for registration of the kinesthetic evoked potentials allows a more detailed study of the mechanisms of kinesthetic sensitivity in health and in organic involvement of the brain.

Audiological characteristics of infants with abnormal transient evoked otoacoustic emission and normal auditory brainstem response.

PubMed

Huang, Lihui; Han, Demin; Guo, Ying; Liu, Sha; Cui, Xiaoyan; Mo, Lingyan; Qi, Beier; Cai, Zhenghua; Liu, Hui; En, Hui; Guo, Liansheng

2008-10-01

Audiological characteristics were investigated in 81 ears of 53 infants with abnormal transient evoked otoacoustic emission (TEOAE) and normal auditory brainstem response (ABR). The relationship between ABR and other hearing testing methods, including 40Hz auditory event-related potential (40Hz-AERP), auditory steady state response (ASSR), distortion product otoacoustic emission (DPOAE), tympanometry, and acoustic reflex, was analyzed. Of the 81 ears, 18 ears (22.2%) were normal, while 63 ears (77.8%) were abnormal according to the tests. Testing of the 40 Hz AERP (36 ears) and ASSR (45 ears) revealed that 14 ears (38.9%) and 27 ears (60.0%) were abnormal, respectively. Testing of DPOAE in 68 ears revealed that 50 ears (73.5%) were abnormal. Testing of tympanometry in 50 ears and acoustic reflex in 47 ears revealed that 9 ears (18%) and 27 ears (57.4%) were abnormal, respectively. The present data suggests that the hearing of infants cannot be sufficiently evaluated with ABR only and that it must be evaluated with integrative audiological testing methods.

The Use of Structural-Acoustic Techniques to Assess Potential Structural Damage From Sonic Booms

NASA Technical Reports Server (NTRS)

Garrelick, Joel; Martini, Kyle

1996-01-01

The potential impact of supersonic operations includes structural damage from the sonic boom overpressure. This paper describes a study of how structural-acoustic modeling and testing techniques may be used to assess the potential for such damage in the absence of actual flyovers. Procedures are described whereby transfer functions relating structural response to sonic boom signature may be obtained with a stationary acoustic source and appropriate data processing. Further, by invoking structural-acoustic reciprocity, these transfer functions may also be acquired by measuring the radiated sound from the structure under a mechanical drive. The approach is based on the fundamental assumption of linearity, both with regard to the (acoustic) propagation of the boom in the vicinity of the structure and to the structure's response. Practical issues revolve around acoustic far field and source directivity requirements. The technique was implemented on a specially fabricated test structure at Edwards AFB, CA with the support of Wyle Laboratories, Inc. Blank shots from a cannon served as our acoustic source and taps from an instrumented hammer generated the mechanical drive. Simulated response functions were constructed. Results of comparisons with corresponding measurements recorded during dedicated supersonic flyovers with F-15 aircraft are presented for a number of sensor placements.

Vestibular short-latency evoked potential abolished by low-frequency noise exposure in rats.

PubMed

Stewart, Courtney E; Kanicki, Ariane C; Altschuler, Richard A; King, W M

2018-02-01

The vestibular system plays a critical role in detection of head movements and is essential for normal postural control. Because of their anatomical proximity to the cochlea, the otolith organs are selectively exposed to sound pressure and are at risk for noise overstimulation. Clinical reports suggest a link between noise exposure and balance problems, but the structural and physiological basis for this linkage is not well understood. The goal of this study was to determine the effects of low-frequency noise (LFN) on the otolith organs by correlating changes in vestibular short-latency evoked potentials (VsEPs) with changes in saccular afferent endings following noise exposure. LFN exposure transiently abolished the VsEP and reduced the number of stained calyces within the sacculus. Although some recovery of the VsEP waveform could be observed within 3 days after noise, at 3 wk recovery was only partial in most animals, consistent with a reduced number of afferents with calyceal endings. These data show that a single intense noise exposure is capable of causing a vestibular deficit that appears to mirror the synaptic deficit associated with hidden hearing loss after noise-induced cochlear injury. NEW & NOTEWORTHY This is the first study to explore the effects of low-frequency high-intensity noise on vestibular short-latency evoked potential (VsEP) responses, which shows a linkage between attenuated noise-induced VsEPs and pathological changes to otolith organ afferents. This finding suggests a potential limitation of the VsEP for evaluation of vestibular dysfunction, since the VsEP measurement may assess the activity of a specific class rather than all afferents.

Basic Hearing and Echolocation Mechanisms of Marine Mammals: Measured Auditory Evoked Potential and Behavioral Experiments FY 2007

DTIC Science & Technology

2007-01-01

Breese, M. (2007) Evoked-potential recovery during double click stimulation in a whale: A possibility of biosonar automatic gain control. Journal of...Yokohama Japan (published) Supin A.Ya, Nachtigall, P.E., and Breese, M. Source level to sensation level ratio of transmitted biosonar pulses in an

Color vision in attention-deficit/hyperactivity disorder: a pilot visual evoked potential study.

PubMed

Kim, Soyeon; Banaschewski, Tobias; Tannock, Rosemary

2015-01-01

Individuals with attention-deficit/hyperactivity disorder (ADHD) are reported to manifest visual problems (including ophthalmological and color perception, particularly for blue-yellow stimuli), but findings are inconsistent. Accordingly, this study investigated visual function and color perception in adolescents with ADHD using color Visual Evoked Potentials (cVEP), which provides an objective measure of color perception. Thirty-one adolescents (aged 13-18), 16 with a confirmed diagnosis of ADHD, and 15 healthy peers, matched for age, gender, and IQ participated in the study. All underwent an ophthalmological exam, as well as electrophysiological testing color Visual Evoked Potentials (cVEP), which measured the latency and amplitude of the neural P1 response to chromatic (blue-yellow, red-green) and achromatic stimuli. No intergroup differences were found in the ophthalmological exam. However, significantly larger P1 amplitude was found for blue and yellow stimuli, but not red/green or achromatic stimuli, in the ADHD group (particularly in the medicated group) compared to controls. Larger amplitude in the P1 component for blue-yellow in the ADHD group compared to controls may account for the lack of difference in color perception tasks. We speculate that the larger amplitude for blue-yellow stimuli in early sensory processing (P1) might reflect a compensatory strategy for underlying problems including compromised retinal input of s-cones due to hypo-dopaminergic tone. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Electromagnetic interference in intraoperative monitoring of motor evoked potentials and a wireless solution.

PubMed

Farajidavar, Aydin; Seifert, Jennifer L; Delgado, Mauricio R; Sparagana, Steven; Romero-Ortega, Mario I; Chiao, J-C

2016-02-01

Intraoperative neurophysiological monitoring (IONM) is utilized to minimize neurological morbidity during spine surgery. Transcranial motor evoked potentials (TcMEPs) are principal IONM signals in which the motor cortex of the subject is stimulated with electrical pulses and the evoked potentials are recorded from the muscles of interest. Currently available monitoring systems require the connection of 40-60 lengthy lead wires to the patient. These wires contribute to a crowded and cluttered surgical environment, and limit the maneuverability of the surgical team. In this work, it was demonstrated that the cumbersome wired system is vulnerable to electromagnetic interference (EMI) produced by operating room (OR) equipment. It was hypothesized that eliminating the lengthy recording wires can remove the EMI induced in the IONM signals. Hence, a wireless system to acquire TcMEPs was developed and validated through bench-top and animal experiments. Side-by-side TcMEPs acquisition from the wired and wireless systems in animal experiments under controlled conditions (absence of EMI from OR equipment) showed comparable magnitudes and waveforms, thus demonstrating the fidelity in the signal acquisition of the wireless solution. The robustness of the wireless system to minimize EMI was compared with a wired-system under identical conditions. Unlike the wired-system, the wireless system was not influenced by the electromagnetic waves from the C-Arm X-ray machine and temperature management system in the OR. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

The effects of neck flexion on cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in related sensory cortices

PubMed Central

2012-01-01

Background A flexed neck posture leads to non-specific activation of the brain. Sensory evoked cerebral potentials and focal brain blood flow have been used to evaluate the activation of the sensory cortex. We investigated the effects of a flexed neck posture on the cerebral potentials evoked by visual, auditory and somatosensory stimuli and focal brain blood flow in the related sensory cortices. Methods Twelve healthy young adults received right visual hemi-field, binaural auditory and left median nerve stimuli while sitting with the neck in a resting and flexed (20° flexion) position. Sensory evoked potentials were recorded from the right occipital region, Cz in accordance with the international 10–20 system, and 2 cm posterior from C4, during visual, auditory and somatosensory stimulations. The oxidative-hemoglobin concentration was measured in the respective sensory cortex using near-infrared spectroscopy. Results Latencies of the late component of all sensory evoked potentials significantly shortened, and the amplitude of auditory evoked potentials increased when the neck was in a flexed position. Oxidative-hemoglobin concentrations in the left and right visual cortices were higher during visual stimulation in the flexed neck position. The left visual cortex is responsible for receiving the visual information. In addition, oxidative-hemoglobin concentrations in the bilateral auditory cortex during auditory stimulation, and in the right somatosensory cortex during somatosensory stimulation, were higher in the flexed neck position. Conclusions Visual, auditory and somatosensory pathways were activated by neck flexion. The sensory cortices were selectively activated, reflecting the modalities in sensory projection to the cerebral cortex and inter-hemispheric connections. PMID:23199306

The hybrid BCI system for movement control by combining motor imagery and moving onset visual evoked potential.

PubMed

Ma, Teng; Li, Hui; Deng, Lili; Yang, Hao; Lv, Xulin; Li, Peiyang; Li, Fali; Zhang, Rui; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2017-04-01

Movement control is an important application for EEG-BCI (EEG-based brain-computer interface) systems. A single-modality BCI cannot provide an efficient and natural control strategy, but a hybrid BCI system that combines two or more different tasks can effectively overcome the drawbacks encountered in single-modality BCI control. In the current paper, we developed a new hybrid BCI system by combining MI (motor imagery) and mVEP (motion-onset visual evoked potential), aiming to realize the more efficient 2D movement control of a cursor. The offline analysis demonstrates that the hybrid BCI system proposed in this paper could evoke the desired MI and mVEP signal features simultaneously, and both are very close to those evoked in the single-modality BCI task. Furthermore, the online 2D movement control experiment reveals that the proposed hybrid BCI system could provide more efficient and natural control commands. The proposed hybrid BCI system is compensative to realize efficient 2D movement control for a practical online system, especially for those situations in which P300 stimuli are not suitable to be applied.

The color-vision approach to emotional space: cortical evoked potential data.

PubMed

Boucsein, W; Schaefer, F; Sokolov, E N; Schröder, C; Furedy, J J

2001-01-01

A framework for accounting for emotional phenomena proposed by Sokolov and Boucsein (2000) employs conceptual dimensions that parallel those of hue, brightness, and saturation in color vision. The approach that employs the concepts of emotional quality. intensity, and saturation has been supported by psychophysical emotional scaling data gathered from a few trained observers. We report cortical evoked potential data obtained during the change between different emotions expressed in schematic faces. Twenty-five subjects (13 male, 12 female) were presented with a positive, a negative, and a neutral computer-generated face with random interstimulus intervals in a within-subjects design, together with four meaningful and four meaningless control stimuli made up from the same elements. Frontal, central, parietal, and temporal ERPs were recorded from each hemisphere. Statistically significant outcomes in the P300 and N200 range support the potential fruitfulness of the proposed color-vision-model-based approach to human emotional space.

Mapping human brain networks with cortico-cortical evoked potentials.

PubMed

Keller, Corey J; Honey, Christopher J; Mégevand, Pierre; Entz, Laszlo; Ulbert, Istvan; Mehta, Ashesh D

2014-10-05

The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for cortico-cortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods. We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

[Communication and auditory behavior obtained by auditory evoked potentials in mammals, birds, amphibians, and reptiles].

PubMed

Arch-Tirado, Emilio; Collado-Corona, Miguel Angel; Morales-Martínez, José de Jesús

2004-01-01

amphibians, Frog catesbiana (frog bull, 30 animals); reptiles, Sceloporus torcuatus (common small lizard, 22 animals); birds: Columba livia (common dove, 20 animals), and mammals, Cavia porcellus, (guinea pig, 20 animals). With regard to lodging, all animals were maintained at the Institute of Human Communication Disorders, were fed with special food for each species, and had water available ad libitum. Regarding procedure, for carrying out analysis of auditory evoked potentials of brain stem SPL amphibians, birds, and mammals were anesthetized with ketamine 20, 25, and 50 mg/kg, by injection. Reptiles were anesthetized by freezing (6 degrees C). Study subjects had needle electrodes placed in an imaginary line on the half sagittal line between both ears and eyes, behind right ear, and behind left ear. Stimulation was carried out inside a no noise site by means of a horn in free field. The sign was filtered at between 100 and 3,000 Hz and analyzed in a computer for provoked potentials (Racia APE 78). In data shown by amphibians, wave-evoked responses showed greater latency than those of the other species. In reptiles, latency was observed as reduced in comparison with amphibians. In the case of birds, lesser latency values were observed, while in the case of guinea pigs latencies were greater than those of doves but they were stimulated by 10 dB, which demonstrated best auditory threshold in the four studied species. Last, it was corroborated that as the auditory threshold of each species it descends conforms to it advances in the phylogenetic scale. Beginning with these registrations, we care able to say that response for evoked brain stem potential showed to be more complex and lesser values of absolute latency as we advance along the phylogenetic scale; thus, the opposing auditory threshold is better agreement with regard to the phylogenetic scale among studied species. These data indicated to us that seeking of auditory information is more complex in more

Long Latency Auditory Evoked Potential in Term and Premature Infants

PubMed Central

Didoné, Dayane Domeneghini; Garcia, Michele Vargas; da Silveira, Aron Ferreira

2013-01-01

Introduction The research in long latency auditory evokes potentials (LLAEP) in newborns is recent because of the cortical structure maturation, but studies note that these potentials may be evidenced at this age and could be considered as indicators of cognitive development. Purpose To research the exogenous potentials in term and premature infants during their first month of life. Materials and Methods The sample consisted of 25 newborns, 15 term and 10 premature infants. The infants with gestational age under 37 weeks were considered premature. To evaluate the cortical potentials, the infants remained in natural sleep. The LLAEPs were researched binaurally, through insertion earphones, with frequent /ba/ and rare /ga/ speech stimuli in the intensity of 80 dB HL (decibel hearing level). The frequent stimuli presented a total of 80% of the presentations, and the rare, 20%. The data were statistically analyzed. Results The average gestational age of the term infants was 38.9 weeks (± 1.3) and for the premature group, 33.9 weeks (± 1.6). It was possible to observe only the potentials P1 and N1 in both groups, but there was no statistically significant difference for the latencies of the components P1 and N1 (p > 0.05) between the groups. Conclusion It was possible to observe the exogenous components P1 and N1 of the cortical potentials in both term and preterm newborns of no more than 1 month of age. However, there was no difference between the groups. PMID:25992057

Clinical significance of vestibular evoked myogenic potentials in benign paroxysmal positional vertigo.

PubMed

Yang, Won Sun; Kim, Sung Huhn; Lee, Jong Dae; Lee, Won-Sang

2008-12-01

To investigate the vestibular evoked myogenic potentials (VEMPs) resulting in benign paroxysmal positional vertigo (BPPV) patients and to verify its clinical applications in BPPV. A prospective study. Tertiary referral dizziness center. Forty-one patients with diagnosis of BPPV and 92 healthy volunteers who underwent VEMP testing. Patients were treated by canalith repositioning maneuvers according to the affected canal, and testing of VEMP was performed at diagnosis and after treatment. Testing of VEMP was performed in BPPV patients and in the control group. The number of times the canalith repositioning maneuver was repeated until the patient's report of relief from vertigo and findings of negative positioning test were recorded to find out the relationship between VEMP results and the progress of disease. Vestibular evoked myogenic potential results of BPPV patients showed prolonged p13 and n23 latencies compared with those of the control group, and we could not find any significant difference in VEMP latencies between patients with posterior and horizontal canal type of BPPV. The number of times that the maneuver was repeated did not correlate with the degree of latency prolongation, but in the "no response" group, the number of times was considerably greater than that in the "response" group. We found that VEMP latencies are increased in BPPV patients, which may signify neuronal degenerative changes in the macula of the saccule. When an extensive neuronal damage was suspected by VEMP results such as "no response" in VEMP, the disease progress showed a chronic and resistive course. Therefore, we propose that VEMP could be a useful method to determine a clinical prognosis of patients with BPPV.

Altered Automatic Face Processing in Individuals with High-Functioning Autism Spectrum Disorders: Evidence from Visual Evoked Potentials

ERIC Educational Resources Information Center

Fujita, Takako; Kamio, Yoko; Yamasaki, Takao; Yasumoto, Sawa; Hirose, Shinichi; Tobimatsu, Shozo

2013-01-01

Individuals with autism spectrum disorders (ASDs) have different automatic responses to faces than typically developing (TD) individuals. We recorded visual evoked potentials (VEPs) in 10 individuals with high-functioning ASD (HFASD) and 10 TD individuals. Visual stimuli consisted of upright and inverted faces (fearful and neutral) and objects…

Interpreting electrically evoked emissions using a finite-element model of the cochlea

NASA Astrophysics Data System (ADS)

Deo, Niranjan V.; Grosh, Karl; Parthasarathi, Anand

2003-10-01

Electrically evoked otoacoustic emissions (EEOAEs) are used to investigate in vivo cochlear electromechanical function. Electrical stimulation through bipolar electrodes placed very close to the basilar membrane (in the scala vestibuli and scala tympani) gives rise to a narrow frequency range of EEOAEs, limited to around 20 kHz when the electrodes are placed near the 18-kHz best frequency place. Model predictions using a three-dimensional inviscid fluid model in conjunction with a middle ear model [S. Puria and J. B. Allen, J. Acoust. Soc. Am. 104, 3463-3481 (1998)] and a simple model for outer hair cell activity [S. Neely and D. Kim, J. Acoust. Soc. Am. 94, 137-146 (1993)] are used to interpret the experimental results. To estimate effect of viscosity, model results are compared with those obtained for a viscous fluid. The models are solved using a 2.5-D finite-element formulation. Predictions show that the high frequency limit of the excitation is determined by the spatial extent of the current stimulus. The global peaks in the EEOAE spectra are interpreted as constructive interference between electrically evoked backward traveling waves and forward traveling waves reflected from the stapes. Steady state response predictions of the model are presented.

Objective measures of binaural masking level differences and comodulation masking release based on late auditory evoked potentials.

PubMed

Epp, Bastian; Yasin, Ifat; Verhey, Jesko L

2013-12-01

The audibility of important sounds is often hampered due to the presence of other masking sounds. The present study investigates if a correlate of the audibility of a tone masked by noise is found in late auditory evoked potentials measured from human listeners. The audibility of the target sound at a fixed physical intensity is varied by introducing auditory cues of (i) interaural target signal phase disparity and (ii) coherent masker level fluctuations in different frequency regions. In agreement with previous studies, psychoacoustical experiments showed that both stimulus manipulations result in a masking release (i: binaural masking level difference; ii: comodulation masking release) compared to a condition where those cues are not present. Late auditory evoked potentials (N1, P2) were recorded for the stimuli at a constant masker level, but different signal levels within the same set of listeners who participated in the psychoacoustical experiment. The data indicate differences in N1 and P2 between stimuli with and without interaural phase disparities. However, differences for stimuli with and without coherent masker modulation were only found for P2, i.e., only P2 is sensitive to the increase in audibility, irrespective of the cue that caused the masking release. The amplitude of P2 is consistent with the psychoacoustical finding of an addition of the masking releases when both cues are present. Even though it cannot be concluded where along the auditory pathway the audibility is represented, the P2 component of auditory evoked potentials is a candidate for an objective measure of audibility in the human auditory system. Copyright © 2013 Elsevier B.V. All rights reserved.

Correlation analysis of the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in children

PubMed Central

Alvarenga, Kátia de Freitas; Alvarez Bernardez-Braga, Gabriela Rosito; Zucki, Fernanda; Duarte, Josilene Luciene; Lopes, Andrea Cintra; Feniman, Mariza Ribeiro

2013-01-01

Summary Introduction: The effects of lead on children's health have been widely studied. Aim: To analyze the correlation between the long latency auditory evoked potential N2 and cognitive P3 with the level of lead poisoning in Brazilian children. Methods: This retrospective study evaluated 20 children ranging in age from 7 to 14 years at the time of audiological and electrophysiological evaluations. We performed periodic surveys of the lead concentration in the blood and basic audiological evaluations. Furthermore, we studied the auditory evoked potential long latency N2 and cognitive P3 by analyzing the absolute latency of the N2 and P3 potentials and the P3 amplitude recorded at Cz. At the time of audiological and electrophysiological evaluations, the average concentration of lead in the blood was less than 10 ug/dL. Results: In conventional audiologic evaluations, all children had hearing thresholds below 20 dBHL for the frequencies tested and normal tympanometry findings; the auditory evoked potential long latency N2 and cognitive P3 were present in 95% of children. No significant correlations were found between the blood lead concentration and latency (p = 0.821) or amplitude (p = 0.411) of the P3 potential. However, the latency of the N2 potential increased with the concentration of lead in the blood, with a significant correlation (p = 0.030). Conclusion: Among Brazilian children with low lead exposure, a significant correlation was found between blood lead levels and the average latency of the auditory evoked potential long latency N2; however, a significant correlation was not observed for the amplitude and latency of the cognitive potential P3. PMID:25991992

Localizing sources of acoustic emission during the martensitic transformation

NASA Astrophysics Data System (ADS)

Niemann, R.; Kopeček, J.; Heczko, O.; Romberg, J.; Schultz, L.; Fähler, S.; Vives, E.; Mañosa, L.; Planes, A.

2014-06-01

Acoustic avalanches are a general feature of solids under stress, e.g., evoked by external compression or arising from internal processes like martensitic phase transformations. From integral measurements, it is usually concluded that nucleation, phase boundary pinning, or interface incompatibilities during this first-order phase transition all may generate acoustic emission. This paper studies the local sources of acoustic emission to enlight the microscopic mechanisms. From two-dimensional spatially resolved acoustic emission measurement and simultaneous optical observation of the surface, we can identify microstructural events at the phase boundary that lead to acoustic emission. A resolution in the 100-μm range was reached for the location of acoustic emission sources on a coarse-grained Ni-Mn-Ga polycrystal. Both, the acoustic activity and the size distribution of the microstructural transformation events, exhibit power-law behavior. The origin of the acoustic emission are elastically incompatible areas, such as differently oriented martensitic plates that meet each other, lamellae growing up to grain boundaries, and grain boundaries in proximity to transforming grains. Using this result, we propose a model to explain the decrease of the critical exponent under a mechanical stress or magnetic field.

Acoustically-Evoked Auditory Change Complex in Children with Auditory Neuropathy Spectrum Disorder: A Potential Objective Tool for Identifying Cochlear Implant Candidates

PubMed Central

He, Shuman; Grose, John H.; Teagle, Holly F.B.; Woodard, Jennifer; Park, Lisa R.; Hatch, Debora R.; Roush, Patricia; Buchman, Craig A.

2014-01-01

Objective: The overall aim of the study was to evaluate the feasibility of using electrophysiological measures of the auditory change complex (ACC) to identify candidates for cochlear implantation in children with auditory neuropathy spectrum disorder (ANSD). In order to achieve this overall aim, this study 1) assessed the feasibility of measuring the ACC evoked by temporal gaps in a group of children with ANSD across a wide age range; and 2) investigated the association between gap detection thresholds (GDTs) measured by the ACC recordings and open-set speech-perception performance in these subjects. Design: Nineteen children with bilateral ANSD ranging in age between 1.9 to 14.9 yrs (mean: 7.8 yrs) participated in this study. Electrophysiological recordings of the auditory event-related potential (ERP), including the onset ERP response and the ACC, were completed in all subjects and open-set speech perception was evaluated for a subgroup of sixteen subjects. For the ERP recordings, the stimulus was a Gaussian noise presented through ER-3A insert earphones to the test ear. Two stimulation conditions were used. In the “control condition,” the stimulus was an 800-ms Gaussian noise. In the “gapped condition”, the stimuli were two noise segments, each being 400 ms in duration, separated by one of five gaps (i.e. 5, 10, 20, 50, or 100 ms). The inter-stimulation interval was 1200 ms. The aided open-set speech perception ability was assessed using the Phonetically Balanced Kindergarten (PBK) word lists presented at 60 dB SPL using recorded testing material in a sound booth. For speech perception tests, subjects wore their hearing aids at the settings recommended by their clinical audiologists. For a subgroup of five subjects, psychophysical gap detection thresholds for the Gaussian noise were also assessed using a three-interval, three-alternative forced-choice procedure. Results: Responses evoked by the onset of the Gaussian noise (i.e. onset responses) were

The hybrid BCI system for movement control by combining motor imagery and moving onset visual evoked potential

NASA Astrophysics Data System (ADS)

Ma, Teng; Li, Hui; Deng, Lili; Yang, Hao; Lv, Xulin; Li, Peiyang; Li, Fali; Zhang, Rui; Liu, Tiejun; Yao, Dezhong; Xu, Peng

2017-04-01

Objective. Movement control is an important application for EEG-BCI (EEG-based brain-computer interface) systems. A single-modality BCI cannot provide an efficient and natural control strategy, but a hybrid BCI system that combines two or more different tasks can effectively overcome the drawbacks encountered in single-modality BCI control. Approach. In the current paper, we developed a new hybrid BCI system by combining MI (motor imagery) and mVEP (motion-onset visual evoked potential), aiming to realize the more efficient 2D movement control of a cursor. Main result. The offline analysis demonstrates that the hybrid BCI system proposed in this paper could evoke the desired MI and mVEP signal features simultaneously, and both are very close to those evoked in the single-modality BCI task. Furthermore, the online 2D movement control experiment reveals that the proposed hybrid BCI system could provide more efficient and natural control commands. Significance. The proposed hybrid BCI system is compensative to realize efficient 2D movement control for a practical online system, especially for those situations in which P300 stimuli are not suitable to be applied.

Guanfacine potentiates the activation of prefrontal cortex evoked by warning signals.

PubMed

Clerkin, Suzanne M; Schulz, Kurt P; Halperin, Jeffrey M; Newcorn, Jeffrey H; Ivanov, Iliyan; Tang, Cheuk Y; Fan, Jin

2009-08-15

Warning signals evoke an alert state of readiness that prepares for a rapid response by priming a thalamo-frontal-striatal network that includes the dorsolateral prefrontal cortex (DLPFC). Animal models indicate that noradrenergic input is essential for this stimulus-driven activation of DLPFC, but the precise mechanisms involved have not been determined. We tested the role that postsynaptic alpha(2A) adrenoceptors play in the activation of DLPFC evoked by warning cues using a placebo-controlled challenge with the alpha(2A) agonist guanfacine. Sixteen healthy young adults were scanned twice with event-related functional magnetic resonance imaging (fMRI), while performing a simple cued reaction time (RT) task following administration of a single dose of oral guanfacine (1 mg) and placebo in counterbalanced order. The RT task temporally segregates the neural effects of warning cues and motor responses and minimizes mnemonic demands. Warning cues produced a marked reduction in RT accompanied by significant activation in a distributed thalamo-frontal-striatal network, including bilateral DLPFC. Guanfacine selectively increased the cue-evoked activation of the left DLPFC and right anterior cerebellum, although this increase was not accompanied by further reductions in RT. The effects of guanfacine on DLPFC activation were specifically associated with the warning cue and were not seen for visual- or target-related activation. Guanfacine produced marked increases in the cue-evoked activation of DLPFC that correspond to the well-described actions of postsynaptic alpha(2) adrenoceptor stimulation. The current procedures provide an opportunity to test postsynaptic alpha(2A) adrenoceptor function in the prefrontal cortex in the pathophysiology of several psychiatric disorders.

Transcutaneous Electrical Nerve Stimulation Effects on Neglect: A Visual-Evoked Potential Study

PubMed Central

Pitzalis, Sabrina; Spinelli, Donatella; Vallar, Giuseppe; Di Russo, Francesco

2013-01-01

We studied the effects of transcutaneous electrical nerve stimulation (TENS) in six right-brain-damaged patients with left unilateral spatial neglect (USN), using both standard clinical tests (reading, line, and letter cancelation, and line bisection), and electrophysiological measures (steady-state visual-evoked potentials, SSVEP). TENS was applied on left neck muscles for 15′, and measures were recorded before, immediately after, and 60′ after stimulation. Behavioral results showed that the stimulation temporarily improved the deficit in all patients. In cancelation tasks, omissions and performance asymmetries between the two hand-sides were reduced, as well as the rightward deviation in line bisection. Before TENS, SSVEP average latency to stimuli displayed in the left visual half-field [LVF (160 ms)] was remarkably longer than to stimuli shown in the right visual half-field [RVF (120 ms)]. Immediately after TENS, latency to LVF stimuli was 130 ms; 1 h after stimulation the effect of TENS faded, with latency returning to baseline. TENS similarly affected also the latency SSVEP of 12 healthy participants, and their line bisection performance, with effects smaller in size. The present study, first, replicates evidence concerning the positive behavioral effects of TENS on the manifestations of left USN in right-brain-damaged patients; second, it shows putatively related electrophysiological effects on the SSVEP latency. These behavioral and novel electrophysiological results are discussed in terms of specific directional effects of left somatosensory stimulation on egocentric coordinates, which in USN patients are displaced toward the side of the cerebral lesion. Showing that visual-evoked potentials latency is modulated by proprioceptive stimulation, we provide electrophysiological evidence to the effect that TENS may improve some manifestations of USN, with implications for its rehabilitation. PMID:23966919

A computer-controlled, closed-loop infusion system for infusing muscle relaxants: its use during motor-evoked potential monitoring.

PubMed

Stinson, L W; Murray, M J; Jones, K A; Assef, S J; Burke, M J; Behrens, T L; Lennon, R L

1994-02-01

A microcomputer-controlled closed-loop infusion system (MCCLIS) has been developed that provides stable intraoperative levels of partial neuromuscular blockade. Complete neuromuscular blockade interferes with intraoperative motor-evoked potential (MEP) monitoring used for patients undergoing surgical procedures that place them at risk for spinal cord ischemia. Nine patients were studied during which the MCCLIS maintained stable levels of partial neuromuscular blockade and allowed transcranial magnetic motor-evoked potential (TcM-MEP) monitoring during thoracoabdominal aortic aneurysmectomy. The use of TcM-MEP for monitoring intraoperative spinal cord function was balanced against surgical considerations for muscle relaxation with 80% to 90% neuromuscular blockade fulfilling each requirement. Intraoperative adjustment of partial neuromuscular blockade to facilitate TcM-MEP monitoring was also possible with the MCCLIS. The MCCLIS should allow for further investigation into the sensitivity, specificity, and predictability of TcM-MEP monitoring for any patient at risk for intraoperative spinal cord ischemia including those undergoing thoracoabdominal aortic aneurysmectomy.

Event related aspects of somatosensory and auditory evoked potentials: noise or signals?

PubMed

Stowell, H

1985-05-01

The so-called Vertex Potential (VP) of human scalp-conducted and event related brain potential (ERBP), which occur as a slow and often large, biphasic sinusoid within the 100-400 msec time segment after transient stimulation in the three main sensory modalities, are the longest researched of all human evoked potential (EP) phenomena. Its variable amplitude has been directly correlated, in experiments expressly tailored for the purpose, with input/output variables such as the rate of acceleration of given stimulus parameters from a state of relative rest (RM function), interstimulus interval (ISI), stimulus intensity, skin potential and resistance changes (SPR and SRR), the peripheral electroneurogram (ENG), and experimentally isolated C-fiber afference; and with neuropsychological variables such as attention or vigilance, visual acuity, response time, subjective stimulus probability or expectancy, acute pain of both fast and slow kinds, intelligence quotient (IQ), and psychometric personality scores (e.g., extraversion versus introversion and neuroticism versus normality). Unfortunately, the cerebral, neural origins of the VP, if any, are unknown; it is reported as usually absent from cortex-surface EP in those primates and mammals hitherto studied, and also from human extracranial event related magnetic fields of the brain (ERMFb) insofar as these reveal only superficial tangential sources; but a possible analog has been recorded from deep subcortical electrodes during human neurosurgery. In view of the increasing published range and quantity of direct correlates of VP amplitude, and of the scarcity of data about its neuroanatomy and neurophysiology, it seemed a good idea to do some rudimentary signal analysis. Preliminary results from five subjects confirm earlier data: The VP of somatosensory (SEP) and auditory (AEP) evoked potentials, as obtained by scalp-conductance and either averaged or single-epoch, can be resolved into inconsistently stimulus synchronized

Stimulus specificity of a steady-state visual-evoked potential-based brain-computer interface.

PubMed

Ng, Kian B; Bradley, Andrew P; Cunnington, Ross

2012-06-01

The mechanisms of neural excitation and inhibition when given a visual stimulus are well studied. It has been established that changing stimulus specificity such as luminance contrast or spatial frequency can alter the neuronal activity and thus modulate the visual-evoked response. In this paper, we study the effect that stimulus specificity has on the classification performance of a steady-state visual-evoked potential-based brain-computer interface (SSVEP-BCI). For example, we investigate how closely two visual stimuli can be placed before they compete for neural representation in the cortex and thus influence BCI classification accuracy. We characterize stimulus specificity using the four stimulus parameters commonly encountered in SSVEP-BCI design: temporal frequency, spatial size, number of simultaneously displayed stimuli and their spatial proximity. By varying these quantities and measuring the SSVEP-BCI classification accuracy, we are able to determine the parameters that provide optimal performance. Our results show that superior SSVEP-BCI accuracy is attained when stimuli are placed spatially more than 5° apart, with size that subtends at least 2° of visual angle, when using a tagging frequency of between high alpha and beta band. These findings may assist in deciding the stimulus parameters for optimal SSVEP-BCI design.

Stimulus specificity of a steady-state visual-evoked potential-based brain-computer interface

NASA Astrophysics Data System (ADS)

Ng, Kian B.; Bradley, Andrew P.; Cunnington, Ross

2012-06-01

The mechanisms of neural excitation and inhibition when given a visual stimulus are well studied. It has been established that changing stimulus specificity such as luminance contrast or spatial frequency can alter the neuronal activity and thus modulate the visual-evoked response. In this paper, we study the effect that stimulus specificity has on the classification performance of a steady-state visual-evoked potential-based brain-computer interface (SSVEP-BCI). For example, we investigate how closely two visual stimuli can be placed before they compete for neural representation in the cortex and thus influence BCI classification accuracy. We characterize stimulus specificity using the four stimulus parameters commonly encountered in SSVEP-BCI design: temporal frequency, spatial size, number of simultaneously displayed stimuli and their spatial proximity. By varying these quantities and measuring the SSVEP-BCI classification accuracy, we are able to determine the parameters that provide optimal performance. Our results show that superior SSVEP-BCI accuracy is attained when stimuli are placed spatially more than 5° apart, with size that subtends at least 2° of visual angle, when using a tagging frequency of between high alpha and beta band. These findings may assist in deciding the stimulus parameters for optimal SSVEP-BCI design.

Ocular Vestibular Evoked Myogenic Potentials in Response to Three Test Positions and Two Frequencies

PubMed Central

Todai, Janvi K.; Congdon, Sharon L.; Sangi-Haghpeykar, Haleh; Cohen, Helen S.

2014-01-01

Objective To determine how eye closure, test positions, and stimulus frequencies influence ocular vestibular evoked myogenic potentials. Study Design This study used a within-subjects repeated measures design. Methods Twenty asymptomatic subjects were each tested on ocular vestibular evoked myogenic potentials in three head/eye conditions at 500 Hz and 1000 Hz using air-conducted sound: 1) Sitting upright, head erect, eyes open, looking up. 2) Lying supine, neck flexed 30 degrees, eyes open and looking up. 3) Lying supine, neck flexed 30 degrees, eyes closed and relaxed. Four dependent variables measured were n10, p16, amplitude, and threshold. Results The supine position/ eyes open was comparable to sitting/ eyes open and better than supine/ eyes closed. Eyes closed resulted in lower amplitude, higher threshold, and prolonged latency. Significantly fewer subjects provided responses with eyes closed than with eyes open. No significant differences were found between both eyes open conditions. Both n10 and p16 were lower at 1000 Hz than at 500 Hz. Amplitude and threshold were higher at 1000 Hz than at 500 Hz. Conclusion Supine eyes open is a reliable alternative to sitting eyes open in patients who cannot maintain a seated position. Testing at 1000 Hz provides a larger response with a faster onset that fatigues faster than at 500 Hz. The increased variability and decreased response in the eyes closed position suggest that the eyes closed position is not reliable. PMID:24178911

Visual evoked potentials and selective attention to points in space

NASA Technical Reports Server (NTRS)

Van Voorhis, S.; Hillyard, S. A.

1977-01-01

Visual evoked potentials (VEPs) were recorded to sequences of flashes delivered to the right and left visual fields while subjects responded promptly to designated stimuli in one field at a time (focused attention), in both fields at once (divided attention), or to neither field (passive). Three stimulus schedules were used: the first was a replication of a previous study (Eason, Harter, and White, 1969) where left- and right-field flashes were delivered quasi-independently, while in the other two the flashes were delivered to the two fields in random order (Bernoulli sequence). VEPs to attended-field stimuli were enhanced at both occipital (O2) and central (Cz) recording sites under all stimulus sequences, but different components were affected at the two scalp sites. It was suggested that the VEP at O2 may reflect modality-specific processing events, while the response at Cz, like its auditory homologue, may index more general aspects of selective attention.

Sensory physiology assessed by evoked potentials in survivors of poliomyelitis.

PubMed

Prokhorenko, Olga A; Vasconcelos, Olavo M; Lupu, Vitalie D; Campbell, William W; Jabbari, Bahman

2008-10-01

Evidence suggests that sensory loss may occur in a proportion of patients affected by poliomyelitis. We hypothesize that sensory problems may be a lasting sequela in some polio survivors. Sensory pathways in polio survivors were evaluated clinically and electrophysiologically using sensory evoked potentials (SEPs). Patients with sensory deficits or abnormal SEPs were further evaluated by magnetic resonance imaging (MRI). Twenty-two patients were studied. The mean age was 64.7 years (age range: 56-81 years). Clinically, sensory impairments were found in 4 patients. Upper limb SEPs were normal. Lower limb SEPs were abnormal in 10 patients. In 1 patient, clinical and electrographic findings correlated with a patch of atrophy in the spinal cord, as shown by MRI. Sensory derangements may be found in a proportion of aging polio survivors. SEP studies may add sensitivity when evaluating sensory function in this cohort. It remains unclear whether these sensory abnormalities are related to remote poliomyelitis. Further studies are necessary.

A comparative study on long-term evoked auditory and visual potential responses between Schizophrenic patients and normal subjects

PubMed Central

2011-01-01

Background The electrical signals measuring method is recommended to examine the relationship between neuronal activities and measure with the event related potentials (ERPs) during an auditory and a visual oddball paradigm between schizophrenic patients and normal subjects. The aim of this study is to discriminate the activation changes of different stimulations evoked by auditory and visual ERPs between schizophrenic patients and normal subjects. Methods Forty-three schizophrenic patients were selected as experimental group patients, and 40 healthy subjects with no medical history of any kind of psychiatric diseases, neurological diseases, or drug abuse, were recruited as a control group. Auditory and visual ERPs were studied with an oddball paradigm. All the data were analyzed by SPSS statistical software version 10.0. Results In the comparative study of auditory and visual ERPs between the schizophrenic and healthy patients, P300 amplitude at Fz, Cz, and Pz and N100, N200, and P200 latencies at Fz, Cz, and Pz were shown significantly different. The cognitive processing reflected by the auditory and the visual P300 latency to rare target stimuli was probably an indicator of the cognitive function in schizophrenic patients. Conclusions This study shows the methodology of application of auditory and visual oddball paradigm identifies task-relevant sources of activity and allows separation of regions that have different response properties. Our study indicates that there may be slowness of automatic cognitive processing and controlled cognitive processing of visual ERPs compared to auditory ERPs in schizophrenic patients. The activation changes of visual evoked potentials are more regionally specific than auditory evoked potentials. PMID:21542917

Electrically-evoked frequency-following response (EFFR) in the auditory brainstem of guinea pigs.

PubMed

He, Wenxin; Ding, Xiuyong; Zhang, Ruxiang; Chen, Jing; Zhang, Daoxing; Wu, Xihong

2014-01-01

It is still a difficult clinical issue to decide whether a patient is a suitable candidate for a cochlear implant and to plan postoperative rehabilitation, especially for some special cases, such as auditory neuropathy. A partial solution to these problems is to preoperatively evaluate the functional integrity of the auditory neural pathways. For evaluating the strength of phase-locking of auditory neurons, which was not reflected in previous methods using electrically evoked auditory brainstem response (EABR), a new method for recording phase-locking related auditory responses to electrical stimulation, called the electrically evoked frequency-following response (EFFR), was developed and evaluated using guinea pigs. The main objective was to assess feasibility of the method by testing whether the recorded signals reflected auditory neural responses or artifacts. The results showed the following: 1) the recorded signals were evoked by neuron responses rather than by artifact; 2) responses evoked by periodic signals were significantly higher than those evoked by the white noise; 3) the latency of the responses fell in the expected range; 4) the responses decreased significantly after death of the guinea pigs; and 5) the responses decreased significantly when the animal was replaced by an electrical resistance. All of these results suggest the method was valid. Recording obtained using complex tones with a missing fundamental component and using pure tones with various frequencies were consistent with those obtained using acoustic stimulation in previous studies.

Generators of the brainstem auditory evoked potential in cat. II. Correlating lesion sites with waveform changes.

PubMed

Melcher, J R; Guinan, J J; Knudson, I M; Kiang, N Y

1996-04-01

Brainstem regions involved in generating the brainstem auditory evoked potential (BAEP) were identified by examining the effects of lesions on the click-evoked BAEP in cats. An excitotoxin, kainic acid, was injected into various parts of the cochlear nucleus (CN) or into the superior olivary complex (SOC). The locations of the resulting lesions were correlated with the changes produced in the various extrema of the BAEP waveforms. The results indicate that: (1) the earliest BAEP extrema (P1, N1 (recorded between vertex and the earbar ipsilateral to the stimulus) and P1a, P1b, (vertex to contralateral earbar)) are generated by cells with somata peripheral to the CN; (2) P2 is primarily generated by posterior anteroventral CN (AVCNp) and anterior posteroventral CN (PVCNa) cells; (3) SOC, anterior anteroventral CN (AVCNa), AVCNp, and PVCNa cells are involved in generating P3; (4) AVCNa cells are the main CN cells involved in P4, N4, and P5 generation; (5) both ipsilateral and contralateral SOC cells have a role in generating monaurally evoked P4 and P5; and (6) P5 is generated by cells with characteristic frequencies below 10 kHz. From (2) and (4), it is clear that P2 and P4-P5 are generated by cells in distinct, parallel pathways.

Cortical Auditory Evoked Potentials to Evaluate Cochlear Implant Candidacy in an Ear With Long-standing Hearing Loss: A Case Report.

PubMed

Patel, Tirth R; Shahin, Antoine J; Bhat, Jyoti; Welling, D Bradley; Moberly, Aaron C

2016-10-01

We describe a novel use of cortical auditory evoked potentials in the preoperative workup to determine ear candidacy for cochlear implantation. A 71-year-old male was evaluated who had a long-deafened right ear, had never worn a hearing aid in that ear, and relied heavily on use of a left-sided hearing aid. Electroencephalographic testing was performed using free field auditory stimulation of each ear independently with pure tones at 1000 and 2000 Hz at approximately 10 dB above pure-tone thresholds for each frequency and for each ear. Mature cortical potentials were identified through auditory stimulation of the long-deafened ear. The patient underwent successful implantation of that ear. He experienced progressively improving aided pure-tone thresholds and binaural speech recognition benefit (AzBio score of 74%). Findings suggest that use of cortical auditory evoked potentials may serve a preoperative role in ear selection prior to cochlear implantation. © The Author(s) 2016.

[Development of auditory evoked potentials of the brainstem in relation to age].

PubMed

Tarantino, V; Stura, M; Vallarino, R

1988-01-01

In order to study the various changes which occur in the waveform, latency and amplitude of the auditory brainstem evoked response (BSER) as a function of age, the authors recorded the BSER from the scalp's surface of 20 newborns and 50 infants, 3 months, 6 months, 1 year and 3 years old as well as from 20 normal adults. The data obtained show that the most reliable waves during the first month of life are waves I, III, V, which is often present even when other vertex-positive peaks are absent. The latencies of the various potential components decreased with maturation. Wave V, evoked by 90 dB sensation level clicks, changed in latency from 7, 12 msec at 1-4 weeks of age to 5,77 msec at 3 years of life. The auditory processes related to peripheral and central transmission were shown to mature at differential rates during the first period of life. By the 6th month, in fact, wave I latency had reached the adult value; in contrast, wave V latency did match that of the adult until approximately 1 year old. One obvious explanation for the age-related latency shift is progressive myelination of the auditory tract in infants, for this is know to occur. The authors conclude that the clinical application of this technique in paediatric patients couldn't provide reliable informations about auditory brain stem activity regardless of evaluation of the relationship between age and characteristics of BSER.

Auditory Evoked Potentials and Hand Preference in 6-Month-Old Infants: Possible Gender-Related Differences in Cerebral Organization.

ERIC Educational Resources Information Center

Shucard, Janet L.; Shucard, David W.

1990-01-01

Verbal and musical stimuli were presented to infants in a study of the relations of evoked potential left-right amplitude asymmetries to gender and hand preference. There was a relation between asymmetry and hand preference, and for girls, between asymmetry and stimulus condition. Results suggest a gender difference in cerebral hemisphere…

Real-Time Detection and Monitoring of Acute Brain Injury Utilizing Evoked Electroencephalographic Potentials.

PubMed

Fisher, Jonathan A N; Huang, Stanley; Ye, Meijun; Nabili, Marjan; Wilent, W Bryan; Krauthamer, Victor; Myers, Matthew R; Welle, Cristin G

2016-09-01

Rapid detection and diagnosis of a traumatic brain injury (TBI) can significantly improve the prognosis for recovery. Helmet-mounted sensors that detect impact severity based on measurements of acceleration or pressure show promise for aiding triage and transport decisions in active, field environments such as professional sports or military combat. The detected signals, however, report on the mechanics of an impact rather than directly indicating the presence and severity of an injury. We explored the use of cortical somatosensory evoked electroencephalographic potentials (SSEPs) to detect and track, in real-time, neural electrophysiological abnormalities within the first hour following head injury in an animal model. To study the immediate electrophysiological effects of injury in vivo, we developed an experimental paradigm involving focused ultrasound that permits continuous, real-time measurements and minimizes mechanical artifact. Injury was associated with a dramatic reduction of amplitude over the damaged hemisphere directly after the injury. The amplitude systematically improved over time but remained significantly decreased at one hour, compared with baseline. In contrast, at one hour there was a concomitant enhancement of the cortical SSEP amplitude evoked from the uninjured hemisphere. Analysis of the inter-trial electroencephalogram (EEG) also revealed significant changes in low-frequency components and an increase in EEG entropy up to 30 minutes after injury, likely reflecting altered EEG reactivity to somatosensory stimuli. Injury-induced alterations in SSEPs were also observed using noninvasive epidermal electrodes, demonstrating viability of practical implementation. These results suggest cortical SSEPs recorded at just a few locations by head-mounted sensors and associated multiparametric analyses could potentially be used to rapidly detect and monitor brain injury in settings that normally present significant levels of mechanical and electrical

Amplitude modulation of steady-state visual evoked potentials by event-related potentials in a working memory task

PubMed Central

Yao, Dezhong; Tang, Yu; Huang, Yilan; Su, Sheng

2009-01-01

Previous studies have shown that the amplitude and phase of the steady-state visual-evoked potential (SSVEP) can be influenced by a cognitive task, yet the mechanism of this influence has not been understood. As the event-related potential (ERP) is the direct neural electric response to a cognitive task, studying the relationship between the SSVEP and ERP would be meaningful in understanding this underlying mechanism. In this work, the traditional average method was applied to extract the ERP directly, following the stimulus of a working memory task, while a technique named steady-state probe topography was utilized to estimate the SSVEP under the simultaneous stimulus of an 8.3-Hz flicker and a working memory task; a comparison between the ERP and SSVEP was completed. The results show that the ERP can modulate the SSVEP amplitude, and for regions where both SSVEP and ERP are strong, the modulation depth is large. PMID:19960240

Vestibular evoked myogenic potentials in patients with ankylosing spondylitis.

PubMed

Özgür, Abdulkadir; Serdaroğlu Beyazal, Münevver; Terzi, Suat; Coşkun, Zerrin Özergin; Dursun, Engin

2016-10-01

Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease with unknown etiology. Although sacroiliac joint involvement is the classic sign along with the formed immune mediators, it may result in immune-mediated inner ear disease and may cause damage to the audiovestibular system. Vestibular evoked myogenic potentials (VEMP) is a clinical reflex test used in the diagnosis of vestibular diseases and is performed by recording and evaluating the muscle potentials resulting from the stimulation of the vestibular system with different stimuli. The aim of this study is to evaluate the cervical VEMP test results in AS patients without vestibular symptoms. Thirty-three patients with AS and a control group of 30 healthy volunteers with similar demographic characteristics were evaluated in the study. VEMP wave latency, P13-N23 wave amplitude, and VEMP asymmetry ratio (VAR) values were compared between the groups. The relationship between clinical and laboratory findings of the AS patients and VEMP data were also investigated. Compared with healthy people, this study shows the response rate of patients with ankylosing spondylitis was reduced in the VEMP test, and P13-N23 wave amplitude showed a decrease in AS patients who had VEMP response (p < 0.001). There was no correlation between the clinical and laboratory findings and VEMP findings in patients with ankylosing spondylitis. The data obtained from this study suggest that AS may lead to decreased sensitivity of the vestibular system.

Spatial adaptation of the cortical visual evoked potential of the cat.

PubMed

Bonds, A B

1984-06-01

Adaptation that is spatially specific for the adapting pattern has been seen psychophysically in humans. This is indirect evidence for independent analyzers (putatively single units) that are specific for orientation and spatial frequency in the human visual system, but it is unclear how global adaptation characteristics may be related to single unit performance. Spatially specific adaptation was sought in the cat visual evoked potential (VEP), with a view towards relating this phenomenon with what we know of cat single units. Adaptation to sine-wave gratings results in a temporary loss of cat VEP amplitude, with induction and recovery similar to that seen in human psychophysical experiments. The amplitude loss was specific for both the spatial frequency and orientation of the adapting pattern. The bandwidth of adaptation was not unlike the average selectivity of a population of cat single units.

Possible long term effects of chemical warfare using visual evoked potentials.

PubMed

Riazi, Abbas; Hafezi, Rhamatollah; Babaei, Mahmoud; Naderi, Mostafa

2014-09-01

Some studies have already addressed the effects of occupational organic solvent exposure on the visually evoked potentials (VEPs). Visual system is an important target for Sulphur Mustard (SM) toxicity. A number of Iranian victims of Sulphur Mustard (SM) agent were apprehensive about the delay effect of SM on their vision and a possible delay effect of SM on their visual cortex. This investigation was performed on 34 individuals with a history of chemical exposure and a control group of 15 normal people. The Toennies electro-diagnosis device was used and its signals were saved as the latencies. The mean of N75, N140 and P100 of victims of chemical warfare (VCWs) and control group indicated no significant results (P>0.05). The VCWs did not show any visual symptoms and there was no clear deficit in their VEPs.

Low-frequency tone-pip-evoked otoacoustic emissions originate over a broad cochlear region in chinchillas

NASA Astrophysics Data System (ADS)

Charaziak, Karolina K.; Siegel, Jonathan H.

2015-12-01

Otoacoustic emissions evoked with transient sounds (TEOAEs) are believed to originate within the tonotopic region of the stimulus in the cochlea via the same mechanisms as emissions evoked with single tones. However, we found that emissions evoked by low frequency (< 3 kHz) single-tones have an extended region of generation (> 6 mm) in chinchillas (Charaziak and Siegel, 2014, ARO Abst., 119). Here we test whether a broad region of generation for low-frequency stimuli is also a characteristic of TEOAEs evoked with 1-kHz tone pips extracted with compression and suppression methods. The TEOAE could be revealed with moderate level suppressors with frequencies extending beyond the stimulus bandwidth (up to 12.1 kHz), with the largest responses obtained with 3.1 - 4.1 kHz suppressors. There was a consistent decline in group delays of suppressor-revealed TEOAEs with increasing suppressor frequency, as expected if higher-frequency suppressors acted on more basal TEOAE generators. Effects of mid- to high-frequency acoustic trauma on TEOAE levels confirm the notion that the suppressors interact with emission components arising near the tonotopic place of the suppressor.

A Bayesian approach to estimate evoked potentials.

PubMed

Sparacino, Giovanni; Milani, Stefano; Arslan, Edoardo; Cobelli, Claudio

2002-06-01

Several approaches, based on different assumptions and with various degree of theoretical sophistication and implementation complexity, have been developed for improving the measurement of evoked potentials (EP) performed by conventional averaging (CA). In many of these methods, one of the major challenges is the exploitation of a priori knowledge. In this paper, we present a new method where the 2nd-order statistical information on the background EEG and on the unknown EP, necessary for the optimal filtering of each sweep in a Bayesian estimation framework, is, respectively, estimated from pre-stimulus data and obtained through a multiple integration of a white noise process model. The latter model is flexible (i.e. it can be employed for a large class of EP) and simple enough to be easily identifiable from the post-stimulus data thanks to a smoothing criterion. The mean EP is determined as the weighted average of the filtered sweeps, where each weight is inversely proportional to the expected value of the norm of the correspondent filter error, a quantity determinable thanks to the employment of the Bayesian approach. The performance of the new approach is shown on both simulated and real auditory EP. A signal-to-noise ratio enhancement is obtained that can allow the (possibly automatic) identification of peak latencies and amplitudes with less sweeps than those required by CA. For cochlear EP, the method also allows the audiology investigator to gather new and clinically important information. The possibility of handling single-sweep analysis with further development of the method is also addressed.

Consistent latencies of vestibular evoked myogenic potentials.

PubMed

Wang, Shou-Jen; Yeh, Te-Huei; Chang, Chun-Hsiang; Young, Yi-Ho

2008-12-01

This study investigated the association between neck length and vestibular evoked myogenic potential (VEMP) latencies in healthy children, adolescents, and adults to elucidate when VEMP latencies reach consistent levels. Findings of VEMP tests in 14 healthy children, seven healthy adolescents, and 14 healthy adults were analyzed for correlations with neck length, which was measured as the distance of a line dropping vertically from the mastoid tip to the horizontal plane passing through the clavicle. All healthy children, adolescents, and adults exhibited present VEMP responses. Children, adolescents, and adults significantly differed in p13 latency, n23 latency, and p13-n23 interval. According to receiver operating characteristic curve analysis, the optimal cutoff values of p13 and n23 latencies between children and adults were 12.6 and 19.8 msec, respectively. Because the odds ratio of p13 latency was less than that of n23 latency, n23 latency was used to discriminate VEMP latencies between children and adults. Accordingly, a cutoff value of 15.3 cm for neck length was proposed as a criterion for predicting VEMP latency within the adult range. Consequently, a positive correlation between neck length and VEMP latency was observed when neck length was <15.3 cm, while above which level one need not account for neck length in evaluating VEMP latency. The intra-subject variability of norms can be enhanced if the normative data for VEMP characteristic parameters take structural variance into account. This study suggests that the adult range of VEMP latencies can be anticipated if neck length is >15.3 cm.

Underwater Anesthesia of Diamondback Terrapins (Malaclemys terrapin) for Measurement of Auditory Evoked Potentials

PubMed Central

Christiansen, Emily F; Piniak, Wendy E D; Lester, Lori A; Harms, Craig A

2013-01-01

Investigations into the biology of aquatic and semiaquatic species, including those involving sensory specialization, often require creative solutions to novel questions. We developed a technique for safely anesthetizing a semiaquatic chelonian species, the diamondback terrapin (Malaclemys terrapin), for measurement of auditory evoked potentials while animals were completely submerged in water. Custom-modified endotracheal tubes were used to obtain a watertight seal on both sides of the glottis and prevent aspiration of water during testing. No adverse effects were seen after the procedures, and assessment of venous blood-gas partial pressures and lactate concentrations indicated that sufficient gas exchange was maintained under anesthesia through manual ventilation. PMID:24351768

Influence of visual angle on pattern reversal visual evoked potentials

PubMed Central

Kothari, Ruchi; Singh, Smita; Singh, Ramji; Shukla, A. K.; Bokariya, Pradeep

2014-01-01

Purpose: The aim of this study was to find whether the visual evoked potential (VEP) latencies and amplitude are altered with different visual angles in healthy adult volunteers or not and to determine the visual angle which is the optimum and most appropriate among a wide range of check sizes for the reliable interpretation of pattern reversal VEPs (PRVEPs). Materials and Methods: The present study was conducted on 40 healthy volunteers. The subjects were divided into two groups. One group consisted of 20 individuals (nine males and 11 females) in the age range of 25-57 years and they were exposed to checks subtending a visual angle of 90, 120, and 180 minutes of arc. Another group comprised of 20 individuals (10 males and 10 females) in the age range of 36-60 years and they were subjected to checks subtending a visual angle of 15, 30, and 120 minutes of arc. The stimulus configuration comprised of the transient pattern reversal method in which a black and white checker board is generated (full field) on a VEP Monitor by an Evoked Potential Recorder (RMS EMG. EPMARK II). The statistical analysis was done by One Way Analysis of Variance (ANOVA) using EPI INFO 6. Results: In Group I, the maximum (max.) P100 latency of 98.8 ± 4.7 and the max. P100 amplitude of 10.05 ± 3.1 μV was obtained with checks of 90 minutes. In Group II, the max. P100 latency of 105.19 ± 4.75 msec as well as the max. P100 amplitude of 8.23 ± 3.30 μV was obtained with 15 minutes. The min. P100 latency in both the groups was obtained with checks of 120 minutes while the min. P100 amplitude was obtained with 180 minutes. A statistically significant difference was derived between means of P100 latency for 15 and 30 minutes with reference to its value for 120 minutes and between the mean value of P100 amplitude for 120 minutes and that of 90 and 180 minutes. Conclusion: Altering the size of stimulus (visual angle) has an effect on the PRVEP parameters. Our study found that the 120 is the

Brain-stem evoked potentials and noise effects in seagulls.

PubMed

Counter, S A

1985-01-01

Brain-stem auditory evoked potentials (BAEP) recorded from the seagull were large-amplitude, short-latency, vertex-positive deflections which originate in the eighth nerve and several brain-stem nuclei. BAEP waveforms were similar in latency and configurations to that reported for certain other lower vertebrates and some mammals. BAEP recorded at several pure tone frequencies throughout the seagull's auditory spectrum showed an area of heightened auditory sensitivity between 1 and 3 kHz. This range was also found to be the primary bandwidth of the vocalization output of young seagulls. Masking by white noise and pure tones had remarkable effects on several parameters of the BAEP. In general, the tone- and click-induced BAEP were either reduced or obliterated by both pure tone and white noise maskers of specific signal to noise ratios and high intensity levels. The masking effects observed in this study may be related to the manner in which seagulls respond to intense environmental noise. One possible conclusion is that intense environmental noise, such as aircraft engine noise, may severely alter the seagull's localization apparatus and induce sonogenic stress, both of which could cause collisions with low-flying aircraft.

The Relationship between Parameters of Long-Latency Evoked Potentials in a Multisensory Design.

PubMed

Hernández, Oscar H; García-Martínez, Rolando; Monteón, Victor

2016-10-01

In previous papers, we have shown that parameters of the omitted stimulus potential (OSP), which occurs at the end of a train of sensory stimuli, strongly depend on the modality. A train of stimuli also produces long-latency evoked potentials (LLEP) at the beginning of the train. This study is an extension of the OSP research, and it tested the relationship between parameters (ie, rate of rise, amplitude, and peak latency) of the P2 waves when trains of auditory, visual, or somatosensory stimuli were applied. The dynamics of the first 3 potentials in the train, related to habituation, were also studied. Twenty healthy young college volunteers participated in the study. As in the OSP, the P2 was faster and higher for auditory than for visual or somatosensory stimuli. The first P2 was swifter and higher than the second and the third potentials. The strength of habituation depends on the sensory modality and the parameter used. All these findings support the view that many long-latency brain potentials could share neural mechanisms related to wave generation. © EEG and Clinical Neuroscience Society (ECNS) 2015.

Experience-dependent increase in spine calcium evoked by backpropagating action potentials in layer 2/3 pyramidal neurons in rat somatosensory cortex.

PubMed

Krieger, Patrik

2009-11-01

In spines on basal dendrites of layer 2/3 pyramidal neurons in somatosensory barrel cortex, calcium transients evoked by back-propagating action potentials (bAPs) were investigated (i) along the length of the basal dendrite, (ii) with postnatal development and (iii) with sensory deprivation during postnatal development. Layer 2/3 pyramidal neurons were investigated at three different ages. At all ages [postnatal day (P)8, P14, P21] the bAP-evoked calcium transient amplitude increased with distance from the soma with a peak at around 50 microm, followed by a gradual decline in amplitude. The effect of sensory deprivation on the bAP-evoked calcium was investigated using two different protocols. When all whiskers on one side of the rat snout were trimmed daily from P8 to P20-24 there was no difference in the bAP-evoked calcium transient between cells in the contralateral hemisphere, lacking sensory input from the whisker, and cells in the ipsilateral barrel cortex, with intact whisker activation. When, however, only the D-row whiskers on one side were trimmed the distribution of bAP-evoked calcium transients in spines was shifted towards larger amplitudes in cells located in the deprived D-column. In conclusion, (i) the bAP-evoked calcium transient gradient along the dendrite length is established at P8, (ii) the calcium transient increases in amplitude with age and (iii) this increase is enhanced in layer 2/3 pyramidal neurons located in a sensory-deprived barrel column that is bordered by non-deprived barrel columns.

Captured by the pain: pain steady-state evoked potentials are not modulated by selective spatial attention.

PubMed

Blöchl, Maria; Franz, Marcel; Miltner, Wolfgang H R; Weiss, Thomas

2015-04-07

Attention has been shown to affect the neural processing of pain. However, the exact mechanisms underlying this modulation remain unknown. Here, we used a new method called pain steady-state evoked potentials (PSSEPs) to investigate whether selective spatial attention affects EEG responses to tonic painful stimuli. In general, steady-state evoked potentials reflect changes in the EEG spectrum at a certain frequency that correspond to the frequency of a train of applied stimuli. In this study, high intensity transcutaneous electrical stimulation was delivered to both hands simultaneously with 31 Hz and 37 Hz, respectively. Subject׳s attention was directed to one of the two trains of stimulation in order to detect a small gap that was occasionally interspersed into the stimulus trains. Thereby, they had to ignore the stimulation applied to the other hand. Results show that PSSEPs were induced at 31 Hz and 37 Hz at frontal and central electrodes. PSSEPs occurred contralaterally to the respective hand stimulated with that frequency. Surprisingly, the magnitude of PSSEPs was not modulated by spatial attention towards one of the two stimuli. Our results indicate that attention can hardly be shifted between two simultaneously applied tonic painful stimulations. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous detection of P300 and steady-state visually evoked potentials for hybrid brain-computer interface.

PubMed

Combaz, Adrien; Van Hulle, Marc M

2015-01-01

We study the feasibility of a hybrid Brain-Computer Interface (BCI) combining simultaneous visual oddball and Steady-State Visually Evoked Potential (SSVEP) paradigms, where both types of stimuli are superimposed on a computer screen. Potentially, such a combination could result in a system being able to operate faster than a purely P300-based BCI and encode more targets than a purely SSVEP-based BCI. We analyse the interactions between the brain responses of the two paradigms, and assess the possibility to detect simultaneously the brain activity evoked by both paradigms, in a series of 3 experiments where EEG data are analysed offline. Despite differences in the shape of the P300 response between pure oddball and hybrid condition, we observe that the classification accuracy of this P300 response is not affected by the SSVEP stimulation. We do not observe either any effect of the oddball stimulation on the power of the SSVEP response in the frequency of stimulation. Finally results from the last experiment show the possibility of detecting both types of brain responses simultaneously and suggest not only the feasibility of such hybrid BCI but also a gain over pure oddball- and pure SSVEP-based BCIs in terms of communication rate.

Vestibular evoked myogenic potentials in patients with BPPV.

PubMed

Korres, Stavros; Gkoritsa, Eleni; Giannakakou-Razelou, Dimitra; Yiotakis, Ioannis; Riga, Maria; Nikolpoulos, Thomas P

2011-01-01

The probable cause of Benign Paroxysmal Positional Vertigo (BPPV) is a degeneration of the oto lithic organs (utricle and saccule). The aim of the study is to find possible alterations in Vestibular Evoked Myogenic Potentials (VEMP) recordings in BPPV patients, because the saccule is part of the VEMP pathway. 27 BPPV patients (24 unilateral and 3 bilateral) aged 20 to 70 years and 30 healthy age matched controls. BPPV was diagnosed by the upbeating geotropic nystagmus found in the supine position with the head overextended towards one side. The subjects were investigated with pure tone audiometry, bi-thermal caloric test with electronystagmographic (ENG) recording, and VEMP recording. P1 latency and N1 latency did not present any statistical difference between control ears and affected ears of the BPPV population. The percentage of abnormal VEMP in the BPPV population was statistically higher than in the control ears (p < 0.005). No significant relationship could be shown between the occurrence of Canal Paresis and abnormal VEMP. No relationship was found between the side (right or left ear) where BPPV appeared clinically and the side where abnormal VEMP was registered. BPPV is a clinical entity associated with increased occurrence of abnormal VEMP recordings, possibly due to degeneration of the saccular macula, which is part of the neural VEMP pathway.

Vestibular evoked myogenic potentials in patients with BPPV

PubMed Central

Korres, Stavros; Gkoritsa, Eleni; Giannakakou-Razelou, Dimitra; Yiotakis, Ioannis; Riga, Maria; Nikolpoulos, Thomas P.

2011-01-01

Summary Background The probable cause of Benign Paroxysmal Positional Vertigo (BPPV) is a degeneration of the oto lithic organs (utricle and saccule). The aim of the study is to find possible alterations in Vestibular Evoked Myogenic Potentials (VEMP) recordings in BPPV patients, because the saccule is part of the VEMP pathway. Material/Methods 27 BPPV patients (24 unilateral and 3 bilateral) aged 20 to 70 years and 30 healthy age matched controls. BPPV was diagnosed by the upbeating geotropic nystagmus found in the supine position with the head overextended towards one side. The subjects were investigated with pure tone audiometry, bi-thermal caloric test with electronystagmographic (ENG) recording, and VEMP recording. Results P1 latency and N1 latency did not present any statistical difference between control ears and affected ears of the BPPV population. The percentage of abnormal VEMP in the BPPV population was statistically higher than in the control ears (p<0.005). No significant relationship could be shown between the occurrence of Canal Paresis and abnormal VEMP. No relationship was found between the side (right or left ear) where BPPV appeared clinically and the side where abnormal VEMP was registered. Conclusions BPPV is a clinical entity associated with increased occurrence of abnormal VEMP recordings, possibly due to degeneration of the saccular macula, which is part of the neural VEMP pathway. PMID:21169909

Roles of N-methyl-d-aspartate receptors during the sensory stimulation-evoked field potential responses in mouse cerebellar cortical molecular layer.

PubMed

Xu, Yin-Hua; Zhang, Guang-Jian; Zhao, Jing-Tong; Chu, Chun-Ping; Li, Yu-Zi; Qiu, De-Lai

2017-11-01

The functions of N-methyl-d-aspartate receptors (NMDARs) in cerebellar cortex have been widely studied under in vitro condition, but their roles during the sensory stimulation-evoked responses in the cerebellar cortical molecular layer in living animals are currently unclear. We here investigated the roles of NMDARs during the air-puff stimulation on ipsilateral whisker pad-evoked field potential responses in cerebellar cortical molecular layer in urethane-anesthetized mice by electrophysiological recording and pharmacological methods. Our results showed that cerebellar surface administration of NMDA induced a dose-dependent decrease in amplitude of the facial stimulation-evoked inhibitory responses (P1) in the molecular layer, accompanied with decreases in decay time, half-width and area under curve (AUC) of P1. The IC 50 of NMDA induced inhibition in amplitude of P1 was 46.5μM. In addition, application of NMDA induced significant increases in the decay time, half-width and AUC values of the facial stimulation-evoked excitatory responses (N1) in the molecular layer. Application of an NMDAR blocker, D-APV (250μM) abolished the facial stimulation-evoked P1 in the molecular layer. These results suggested that NMDARs play a critical role during the sensory information processing in cerebellar cortical molecular layer in vivo in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Potential Benefits of an Integrated Electric-Acoustic Sound Processor with Children: A Preliminary Report.

PubMed

Wolfe, Jace; Neumann, Sara; Schafer, Erin; Marsh, Megan; Wood, Mark; Baker, R Stanley

2017-02-01

A number of published studies have demonstrated the benefits of electric-acoustic stimulation (EAS) over conventional electric stimulation for adults with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. These benefits potentially include better speech recognition in quiet and in noise, better localization, improvements in sound quality, better music appreciation and aptitude, and better pitch recognition. There is, however, a paucity of published reports describing the potential benefits and limitations of EAS for children with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. The objective of this study was to explore the potential benefits of EAS for children. A repeated measures design was used to evaluate performance differences obtained with EAS stimulation versus acoustic- and electric-only stimulation. Seven users of Cochlear Nucleus Hybrid, Nucleus 24 Freedom, CI512, and CI422 implants were included in the study. Sentence recognition (assayed using the pediatric version of the AzBio sentence recognition test) was evaluated in quiet and at three fixed signal-to-noise ratios (SNR) (0, +5, and +10 dB). Functional hearing performance was also evaluated with the use of questionnaires, including the comparative version of the Speech, Spatial, and Qualities, the Listening Inventory for Education Revised, and the Children's Home Inventory for Listening Difficulties. Speech recognition in noise was typically better with EAS compared to participants' performance with acoustic- and electric-only stimulation, particularly when evaluated at the less favorable SNR. Additionally, in real-world situations, children generally preferred to use EAS compared to electric-only stimulation. Also, the participants' classroom teachers observed better hearing performance in the classroom with the use of EAS. Use of EAS provided better speech recognition in quiet and in noise when compared to

Comparison of in-air evoked potential and underwater behavioral hearing thresholds in four bottlenose dolphins (Tursiops truncatus).

PubMed

Finneran, James J; Houser, Dorian S

2006-05-01

Traditional behavioral techniques for hearing assessment in marine mammals are limited by the time and access required to train subjects. Electrophysiological methods, where passive electrodes are used to measure auditory evoked potentials (AEPs), are attractive alternatives to behavioral techniques; however, there have been few attempts to compare AEP and behavioral results for the same subject. In this study, behavioral and AEP hearing thresholds were compared in four bottlenose dolphins. AEP thresholds were measured in-air using a piezoelectric sound projector embedded in a suction cup to deliver amplitude modulated tones to the dolphin through the lower jaw. Evoked potentials were recorded noninvasively using surface electrodes. Adaptive procedures allowed AEP hearing thresholds to be estimated from 10 to 150 kHz in a single ear in about 45 min. Behavioral thresholds were measured in a quiet pool and in San Diego Bay. AEP and behavioral threshold estimates agreed closely as to the upper cutoff frequency beyond which thresholds increased sharply. AEP thresholds were strongly correlated with pool behavioral thresholds across the range of hearing; differences between AEP and pool behavioral thresholds increased with threshold magnitude and ranged from 0 to + 18 dB.

Wavelet analysis can sensitively describe dynamics of ethanol evoked local field potentials of the slug (Limax marginatus) brain.

PubMed

Schütt, Atsuko; Ito, Iori; Rosso, Osvaldo A; Figliola, Alejandra

2003-10-30

Odorants evoke characteristic, but complex, local field potentials (LFPs) in the molluscan brain. Wavelet tools in combination with Fourier analysis can detect and characterize hitherto unknown discrete, slow potentials underlying the conspicuous oscillations. Ethanol was one of the odorants that we have extensively studied (J. Neurosci. Methods, 119 (2002) 89). To detect new features and to elucidate their functions, we tested the wavelet tools on the ethanol-evoked LFP responses of the slug (Limax) procerebrum. Recordings were made in vitro from the neuropile and the cell layer. The present study led to the following findings: (i) Mutual exclusion. Energy concentrated mainly in two ranges, (a) 0.1-0.4 Hz and (b) 1.56-12.5 Hz, and the sum of energy remained constant throughout experiments regardless of the condition. A redistribution of relative energy within this sum seemed to occur in the course of main, possible interactions between the two components excluding each other ('mutual exclusion'). (ii) Transient signal ordering and disordering. Ethanol stimulation alternatingly evoked periods of strongly time evolving oscillation dominated by the energy of 1.56-12.5 Hz (increase of entropy=disordered or complexly ordered state) and those of near-silence were predominated by the energy of 0.1-0.4 Hz (decrease of entropy=ordered state). (iii) About 0.1 Hz slow wave oscillation. It was robust. The dominant energy oscillation and the resulting large entropy fluctuation were negatively correlated to each other, and revealed strong frequency-tuning or synchronization at this frequency. Our findings suggest that discrete slow waves play functionally important roles in the invertebrate brain, as widely known in vertebrate EEG. Wavelet tools allow an easy interpretation of several minutes of frequency variations in a single display and give precise information on stimulus-evoked complex change of the neural system describing the new state 'more ordered' or 'non-ordered or

INHIBITION OF BRAIN CHOLINESTERASE AND THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS PRODUCED BY CARBARYL IN LONG EVANS RATS.

EPA Science Inventory

Carbaryl is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response often used to detect central nervous system (CNS) changes following expos...

A high-speed brain speller using steady-state visual evoked potentials.

PubMed

Nakanishi, Masaki; Wang, Yijun; Wang, Yu-Te; Mitsukura, Yasue; Jung, Tzyy-Ping

2014-09-01

Implementing a complex spelling program using a steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) remains a challenge due to difficulties in stimulus presentation and target identification. This study aims to explore the feasibility of mixed frequency and phase coding in building a high-speed SSVEP speller with a computer monitor. A frequency and phase approximation approach was developed to eliminate the limitation of the number of targets caused by the monitor refresh rate, resulting in a speller comprising 32 flickers specified by eight frequencies (8-15 Hz with a 1 Hz interval) and four phases (0°, 90°, 180°, and 270°). A multi-channel approach incorporating Canonical Correlation Analysis (CCA) and SSVEP training data was proposed for target identification. In a simulated online experiment, at a spelling rate of 40 characters per minute, the system obtained an averaged information transfer rate (ITR) of 166.91 bits/min across 13 subjects with a maximum individual ITR of 192.26 bits/min, the highest ITR ever reported in electroencephalogram (EEG)-based BCIs. The results of this study demonstrate great potential of a high-speed SSVEP-based BCI in real-life applications.

Quantification of the proportion of motor neurons recruited by transcranial electrical stimulation during intraoperative motor evoked potential monitoring.

PubMed

Tsutsui, Shunji; Yamada, Hiroshi; Hashizume, Hiroshi; Minamide, Akihito; Nakagawa, Yukihiro; Iwasaki, Hiroshi; Yoshida, Munehito

2013-12-01

Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. However, they are much smaller and more variable in amplitude than responses evoked by maximal peripheral nerve stimulation, suggesting that a limited number of spinal motor neurons to the target muscle are excited by transcranial stimulation. The aim of this study was to quantify the proportion of motor neurons recruited during TcMEP monitoring under general anesthesia. In twenty patients who underwent thoracic and/or lumbar spinal surgery with TcMEP monitoring, the triple stimulation technique (TST) was applied to the unilateral upper arm intraoperatively. Total intravenous anesthesia was employed. Trains of four stimuli were delivered with maximal intensity and an inter-pulse interval of 1.5 ms. TST responses were recorded from the abductor digiti minimi muscle, and the negative peak amplitude and area were measured and compared between the TST test (two collisions between transcranial and proximal and distal peripheral stimulation) and control response (two collisions between two proximal and one distal peripheral stimulation). The highest degree of superimposition of the TST test and control responses was chosen from several trials per patient. The average ratios (test:control) were 17.1 % (range 1.8-38 %) for the amplitudes and 21.6 % (range 2.9-40 %) for the areas. The activity of approximately 80 % of the motor units to the target muscle cannot be detected by TcMEP monitoring. Therefore, changes in evoked potentials must be interpreted cautiously when assessing segmental motor function with TcMEP monitoring.

Adaptive interference cancel filter for evoked potential using high-order cumulants.

PubMed

Lin, Bor-Shyh; Lin, Bor-Shing; Chong, Fok-Ching; Lai, Feipei

2004-01-01

This paper is to present evoked potential (EP) processing using adaptive interference cancel (AIC) filter with second and high order cumulants. In conventional ensemble averaging method, people have to conduct repetitively experiments to record the required data. Recently, the use of AIC structure with second statistics in processing EP has proved more efficiency than traditional averaging method, but it is sensitive to both of the reference signal statistics and the choice of step size. Thus, we proposed higher order statistics-based AIC method to improve these disadvantages. This study was experimented in somatosensory EP corrupted with EEG. Gradient type algorithm is used in AIC method. Comparisons with AIC filter on second, third, fourth order statistics are also presented in this paper. We observed that AIC filter with third order statistics has better convergent performance for EP processing and is not sensitive to the selection of step size and reference input.

Addition of visual noise boosts evoked potential-based brain-computer interface.

PubMed

Xie, Jun; Xu, Guanghua; Wang, Jing; Zhang, Sicong; Zhang, Feng; Li, Yeping; Han, Chengcheng; Li, Lili

2014-05-14

Although noise has a proven beneficial role in brain functions, there have not been any attempts on the dedication of stochastic resonance effect in neural engineering applications, especially in researches of brain-computer interfaces (BCIs). In our study, a steady-state motion visual evoked potential (SSMVEP)-based BCI with periodic visual stimulation plus moderate spatiotemporal noise can achieve better offline and online performance due to enhancement of periodic components in brain responses, which was accompanied by suppression of high harmonics. Offline results behaved with a bell-shaped resonance-like functionality and 7-36% online performance improvements can be achieved when identical visual noise was adopted for different stimulation frequencies. Using neural encoding modeling, these phenomena can be explained as noise-induced input-output synchronization in human sensory systems which commonly possess a low-pass property. Our work demonstrated that noise could boost BCIs in addressing human needs.

Ocular vestibular evoked myogenic potentials elicited with vibration applied to the teeth.

PubMed

Parker-George, Jennifer C; Bell, Steven L; Griffin, Michael J

2016-01-01

This study investigated whether the method for eliciting vibration-induced oVEMPs could be improved by applying vibration directly to the teeth, and how vibration-induced oVEMP responses depend on the duration of the applied vibration. In 10 participants, a hand-held shaker was used to present 100-Hz vibration tone pips to the teeth via a customised bite-bar or to other parts of the head. oVEMP potentials were recorded in response to vibration in three orthogonal directions and five stimulus durations (10-180 ms). The oVEMP responses were analysed in terms of the peak latency onset, peak-to-peak amplitude, and the quality of the trace. Vibration applied to the teeth via the bite-bar produced oVEMPs that were more consistent, of higher quality and of greater amplitude than those evoked by vibration applied to the head. Longer duration stimuli produced longer duration oVEMP responses. One cycle duration stimuli produced responses that were smaller in amplitude and lower quality than the longer stimulus durations. Application of vibration via the teeth using a bite-bar is an effective means of producing oVEMPs. A 1-cycle stimulus is not optimal to evoke an oVEMP because it produces less robust responses than those of longer stimulus duration. A positive relationship between the duration of the stimulus and the response is consistent with the notion that the vibration-induced oVEMP is an oscillatory response to the motion of the head, rather than being a simple reflex response that occurs when the stimulus exceeds a threshold level of stimulation. Applying acceleration to the teeth through a bite-bar elicits clearer oVEMP responses than direct application to other parts of the head and has potential to improve clinical measurements. A 100-Hz 1-cycle stimulus produces less robust oVEMP responses than longer 100-Hz stimuli. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Using Evoked Potentials to Match Interaural Electrode Pairs with Bilateral Cochlear Implants

PubMed Central

Delgutte, Bertrand

2007-01-01

Bilateral cochlear implantation seeks to restore the advantages of binaural hearing to the profoundly deaf by providing binaural cues normally important for accurate sound localization and speech reception in noise. Psychophysical observations suggest that a key issue for the implementation of a successful binaural prosthesis is the ability to match the cochlear positions of stimulation channels in each ear. We used a cat model of bilateral cochlear implants with eight-electrode arrays implanted in each cochlea to develop and test a noninvasive method based on evoked potentials for matching interaural electrodes. The arrays allowed the cochlear location of stimulation to be independently varied in each ear. The binaural interaction component (BIC) of the electrically evoked auditory brainstem response (EABR) was used as an assay of binaural processing. BIC amplitude peaked for interaural electrode pairs at the same relative cochlear position and dropped with increasing cochlear separation in either direction. To test the hypothesis that BIC amplitude peaks when electrodes from the two sides activate maximally overlapping neural populations, we measured multiunit neural activity along the tonotopic gradient of the inferior colliculus (IC) with 16-channel recording probes and determined the spatial pattern of IC activation for each stimulating electrode. We found that the interaural electrode pairings that produced the best aligned IC activation patterns were also those that yielded maximum BIC amplitude. These results suggest that EABR measurements may provide a method for assigning frequency–channel mappings in bilateral implant recipients, such as pediatric patients, for which psychophysical measures of pitch ranking or binaural fusion are unavailable. PMID:17225976

Using evoked potentials to match interaural electrode pairs with bilateral cochlear implants.

PubMed

Smith, Zachary M; Delgutte, Bertrand

2007-03-01

Bilateral cochlear implantation seeks to restore the advantages of binaural hearing to the profoundly deaf by providing binaural cues normally important for accurate sound localization and speech reception in noise. Psychophysical observations suggest that a key issue for the implementation of a successful binaural prosthesis is the ability to match the cochlear positions of stimulation channels in each ear. We used a cat model of bilateral cochlear implants with eight-electrode arrays implanted in each cochlea to develop and test a noninvasive method based on evoked potentials for matching interaural electrodes. The arrays allowed the cochlear location of stimulation to be independently varied in each ear. The binaural interaction component (BIC) of the electrically evoked auditory brainstem response (EABR) was used as an assay of binaural processing. BIC amplitude peaked for interaural electrode pairs at the same relative cochlear position and dropped with increasing cochlear separation in either direction. To test the hypothesis that BIC amplitude peaks when electrodes from the two sides activate maximally overlapping neural populations, we measured multiunit neural activity along the tonotopic gradient of the inferior colliculus (IC) with 16-channel recording probes and determined the spatial pattern of IC activation for each stimulating electrode. We found that the interaural electrode pairings that produced the best aligned IC activation patterns were also those that yielded maximum BIC amplitude. These results suggest that EABR measurements may provide a method for assigning frequency-channel mappings in bilateral implant recipients, such as pediatric patients, for which psychophysical measures of pitch ranking or binaural fusion are unavailable.

[Cortical potentials evoked to response to a signal to make a memory-guided saccade].

PubMed

Slavutskaia, M V; Moiseeva, V V; Shul'govskiĭ, V V

2010-01-01

The difference in parameters of visually guided and memory-guided saccades was shown. Increase in the memory-guided saccade latency as compared to that of the visually guided saccades may indicate the deceleration of saccadic programming on the basis of information extraction from the memory. The comparison of parameters and topography of evoked components N1 and P1 of the evoked potential on the signal to make a memory- or visually guided saccade suggests that the early stage of the saccade programming associated with the space information processing is performed predominantly with top-down attention mechanism before the memory-guided saccade and bottom-up mechanism before the visually guided saccade. The findings show that the increase in the latency of the memory-guided saccades is connected with decision making at the central stage of the saccade programming. We proposed that wave N2, which develops in the middle of the latent period of the memory-guided saccades, is correlated with this process. Topography and spatial dynamics of components N1, P1 and N2 testify that the memory-guided saccade programming is controlled by the frontal mediothalamic system of selective attention and left-hemispheric brain mechanisms of motor attention.

The intra-individual reproducibility of flash-evoked potentials in a sample of children.

PubMed

Schellberg, D; Gasser, T; Köhler, W

1987-07-01

Visual evoked potentials (VEPs) to flash stimuli were recorded twice from 26 children aged 10-13 years, with an intersession interval of about 10 months. Test-retest reliability was poor for recordings taken from scalp locations overlying non-specific cortex and somewhat better for specific cortex. The size of consistency coefficients (i.e. correlations within session) showed that noise and artefacts were not the decisive factors which lower reliability. A comparison with retest correlations of broad band parameters of the EEG at rest for the same sample showed, to our surprise, smaller retest reliability for VEP parameters. Variability of the VEP in children over time seems to be a substantial as its well-known inter-individual variability.

Automated single-trial assessment of laser-evoked potentials as an objective functional diagnostic tool for the nociceptive system.

PubMed

Hatem, S M; Hu, L; Ragé, M; Gierasimowicz, A; Plaghki, L; Bouhassira, D; Attal, N; Iannetti, G D; Mouraux, A

2012-12-01

To assess the clinical usefulness of an automated analysis of event-related potentials (ERPs). Nociceptive laser-evoked potentials (LEPs) and non-nociceptive somatosensory electrically-evoked potentials (SEPs) were recorded in 37 patients with syringomyelia and 21 controls. LEP and SEP peak amplitudes and latencies were estimated using a single-trial automated approach based on time-frequency wavelet filtering and multiple linear regression, as well as a conventional approach based on visual inspection. The amplitudes and latencies of normal and abnormal LEP and SEP peaks were identified reliably using both approaches, with similar sensitivity and specificity. Because the automated approach provided an unbiased solution to account for average waveforms where no ERP could be identified visually, it revealed significant differences between patients and controls that were not revealed using the visual approach. The automated analysis of ERPs characterized reliably and objectively LEP and SEP waveforms in patients. The automated single-trial analysis can be used to characterize normal and abnormal ERPs with a similar sensitivity and specificity as visual inspection. While this does not justify its use in a routine clinical setting, the technique could be useful to avoid observer-dependent biases in clinical research. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Neurophysiological Effects of Meditation Based on Evoked and Event Related Potential Recordings

PubMed Central

Singh, Nilkamal; Telles, Shirley

2015-01-01

Evoked potentials (EPs) are a relatively noninvasive method to assess the integrity of sensory pathways. As the neural generators for most of the components are relatively well worked out, EPs have been used to understand the changes occurring during meditation. Event-related potentials (ERPs) yield useful information about the response to tasks, usually assessing attention. A brief review of the literature yielded eleven studies on EPs and seventeen on ERPs from 1978 to 2014. The EP studies covered short, mid, and long latency EPs, using both auditory and visual modalities. ERP studies reported the effects of meditation on tasks such as the auditory oddball paradigm, the attentional blink task, mismatched negativity, and affective picture viewing among others. Both EP and ERPs were recorded in several meditations detailed in the review. Maximum changes occurred in mid latency (auditory) EPs suggesting that maximum changes occur in the corresponding neural generators in the thalamus, thalamic radiations, and primary auditory cortical areas. ERP studies showed meditation can increase attention and enhance efficiency of brain resource allocation with greater emotional control. PMID:26137479

Neurophysiological Effects of Meditation Based on Evoked and Event Related Potential Recordings.

PubMed

Singh, Nilkamal; Telles, Shirley

2015-01-01

Evoked potentials (EPs) are a relatively noninvasive method to assess the integrity of sensory pathways. As the neural generators for most of the components are relatively well worked out, EPs have been used to understand the changes occurring during meditation. Event-related potentials (ERPs) yield useful information about the response to tasks, usually assessing attention. A brief review of the literature yielded eleven studies on EPs and seventeen on ERPs from 1978 to 2014. The EP studies covered short, mid, and long latency EPs, using both auditory and visual modalities. ERP studies reported the effects of meditation on tasks such as the auditory oddball paradigm, the attentional blink task, mismatched negativity, and affective picture viewing among others. Both EP and ERPs were recorded in several meditations detailed in the review. Maximum changes occurred in mid latency (auditory) EPs suggesting that maximum changes occur in the corresponding neural generators in the thalamus, thalamic radiations, and primary auditory cortical areas. ERP studies showed meditation can increase attention and enhance efficiency of brain resource allocation with greater emotional control.

Does navigated transcranial stimulation increase the accuracy of tractography? A prospective clinical trial based on intraoperative motor evoked potential monitoring during deep brain stimulation.

PubMed

Forster, Marie-Therese; Hoecker, Alexander Claudius; Kang, Jun-Suk; Quick, Johanna; Seifert, Volker; Hattingen, Elke; Hilker, Rüdiger; Weise, Lutz Martin

2015-06-01

Tractography based on diffusion tensor imaging has become a popular tool for delineating white matter tracts for neurosurgical procedures. To explore whether navigated transcranial magnetic stimulation (nTMS) might increase the accuracy of fiber tracking. Tractography was performed according to both anatomic delineation of the motor cortex (n = 14) and nTMS results (n = 9). After implantation of the definitive electrode, stimulation via the electrode was performed, defining a stimulation threshold for eliciting motor evoked potentials recorded during deep brain stimulation surgery. Others have shown that of arm and leg muscles. This threshold was correlated with the shortest distance between the active electrode contact and both fiber tracks. Results were evaluated by correlation to motor evoked potential monitoring during deep brain stimulation, a surgical procedure causing hardly any brain shift. Distances to fiber tracks clearly correlated with motor evoked potential thresholds. Tracks based on nTMS had a higher predictive value than tracks based on anatomic motor cortex definition (P < .001 and P = .005, respectively). However, target site, hemisphere, and active electrode contact did not influence this correlation. The implementation of tractography based on nTMS increases the accuracy of fiber tracking. Moreover, this combination of methods has the potential to become a supplemental tool for guiding electrode implantation.

Pattern visual evoked potentials elicited by organic electroluminescence screen.

PubMed

Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Funada, Hideaki; Sasaki, Kakeru; Minoda, Haruka; Iwata, Takeshi; Mizota, Atsushi

2014-01-01

To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT) screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

Transdiagnostic psychiatric symptoms related to visual evoked potential abnormalities.

PubMed

Bedwell, Jeffrey S; Butler, Pamela D; Chan, Chi C; Trachik, Benjamin J

2015-12-15

Visual processing abnormalities have been reported across a range of psychotic and mood disorders, but are typically examined within a particular disorder. The current study used a novel transdiagnostic approach to examine diagnostic classes, clinician-rated current symptoms, and self-reported personality traits in relation to visual processing abnormalities. We examined transient visual-evoked potentials (VEPs) from 48 adults (56% female), representing a wide range of psychotic and mood disorders, as well as individuals with no history of psychiatric disorder. Stimuli were low contrast check arrays presented on green and red backgrounds. Pairwise comparisons between individuals with schizophrenia-spectrum disorders (SSD), chronic mood disorders (CMD), and nonpsychiatric controls (NC) revealed no overall differences for either P1 or N1 amplitude. However, there was a significant interaction with the color background in which the NC group showed a significant increase in P1 amplitude to the red, vs. green, background, while the SSD group showed no change. This was related to an increase in social anhedonia and general negative symptoms. Stepwise regressions across the entire sample revealed that individuals with greater apathy and/or eccentric behavior had a reduced P1 amplitude. These relationships provide clues for uncovering the underlying causal pathology for these transdiagnostic symptoms. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Turbofan Acoustic Propagation and Radiation

NASA Technical Reports Server (NTRS)

Eversman, Walter

2000-01-01

This document describes progress in the development of finite element codes for the prediction of near and far field acoustic radiation from the inlet and aft fan ducts of turbofan engines. The report consists of nine papers which have appeared in archival journals and conference proceedings, or are presently in review for publication. Topics included are: 1. Aft Fan Duct Acoustic Radiation; 2. Mapped Infinite Wave Envelope Elements for Acoustic Radiation in a Uniformly Moving Medium; 3. A Reflection Free Boundary Condition for Propagation in Uniform Flow Using Mapped Infinite Wave Envelope Elements; 4. A Numerical Comparison Between Multiple-Scales and FEM Solution for Sound Propagation in Lined Flow Ducts; 5. Acoustic Propagation at High Frequencies in Ducts; 6. The Boundary Condition at an Impedance Wall in a Nonuniform Duct with Potential Flow; 7. A Reverse Flow Theorem and Acoustic Reciprocity in Compressible Potential Flows; 8. Reciprocity and Acoustics Power in One Dimensional Compressible Potential Flows; and 9. Numerical Experiments on Acoustic Reciprocity in Compressible Potential Flows.

BRAIN CHOLINESTERASE INHIBITION PRODUCED BY PROPOXUR AND DEPRESSION OF THE PHOTIC AFTER DISCHARGE OF FLASH EVOKED POTENTIALS IN LONG EVANS RATS.

EPA Science Inventory

Propoxur is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response following stimulation of the visual system with flashes of light. They ar...

Primary Generators of Visually Evoked Field Potentials Recorded in the Macaque Auditory Cortex.

PubMed

Kajikawa, Yoshinao; Smiley, John F; Schroeder, Charles E

2017-10-18

Prior studies have reported "local" field potential (LFP) responses to faces in the macaque auditory cortex and have suggested that such face-LFPs may be substrates of audiovisual integration. However, although field potentials (FPs) may reflect the synaptic currents of neurons near the recording electrode, due to the use of a distant reference electrode, they often reflect those of synaptic activity occurring in distant sites as well. Thus, FP recordings within a given brain region (e.g., auditory cortex) may be "contaminated" by activity generated elsewhere in the brain. To determine whether face responses are indeed generated within macaque auditory cortex, we recorded FPs and concomitant multiunit activity with linear array multielectrodes across auditory cortex in three macaques (one female), and applied current source density (CSD) analysis to the laminar FP profile. CSD analysis revealed no appreciable local generator contribution to the visual FP in auditory cortex, although we did note an increase in the amplitude of visual FP with cortical depth, suggesting that their generators are located below auditory cortex. In the underlying inferotemporal cortex, we found polarity inversions of the main visual FP components accompanied by robust CSD responses and large-amplitude multiunit activity. These results indicate that face-evoked FP responses in auditory cortex are not generated locally but are volume-conducted from other face-responsive regions. In broader terms, our results underscore the caution that, unless far-field contamination is removed, LFPs in general may reflect such "far-field" activity, in addition to, or in absence of, local synaptic responses. SIGNIFICANCE STATEMENT Field potentials (FPs) can index neuronal population activity that is not evident in action potentials. However, due to volume conduction, FPs may reflect activity in distant neurons superimposed upon that of neurons close to the recording electrode. This is problematic as the

Primary Generators of Visually Evoked Field Potentials Recorded in the Macaque Auditory Cortex

PubMed Central

Smiley, John F.; Schroeder, Charles E.

2017-01-01

Prior studies have reported “local” field potential (LFP) responses to faces in the macaque auditory cortex and have suggested that such face-LFPs may be substrates of audiovisual integration. However, although field potentials (FPs) may reflect the synaptic currents of neurons near the recording electrode, due to the use of a distant reference electrode, they often reflect those of synaptic activity occurring in distant sites as well. Thus, FP recordings within a given brain region (e.g., auditory cortex) may be “contaminated” by activity generated elsewhere in the brain. To determine whether face responses are indeed generated within macaque auditory cortex, we recorded FPs and concomitant multiunit activity with linear array multielectrodes across auditory cortex in three macaques (one female), and applied current source density (CSD) analysis to the laminar FP profile. CSD analysis revealed no appreciable local generator contribution to the visual FP in auditory cortex, although we did note an increase in the amplitude of visual FP with cortical depth, suggesting that their generators are located below auditory cortex. In the underlying inferotemporal cortex, we found polarity inversions of the main visual FP components accompanied by robust CSD responses and large-amplitude multiunit activity. These results indicate that face-evoked FP responses in auditory cortex are not generated locally but are volume-conducted from other face-responsive regions. In broader terms, our results underscore the caution that, unless far-field contamination is removed, LFPs in general may reflect such “far-field” activity, in addition to, or in absence of, local synaptic responses. SIGNIFICANCE STATEMENT Field potentials (FPs) can index neuronal population activity that is not evident in action potentials. However, due to volume conduction, FPs may reflect activity in distant neurons superimposed upon that of neurons close to the recording electrode. This is

Age-related changes in laser-evoked potentials following trigeminal and hand stimulation in healthy subjects.

PubMed

de Tommaso, M; Ricci, K; Montemurno, A; Vecchio, E

2017-07-01

This study aimed to evaluate age-related changes in laser-evoked potential (LEP) features, including habituation, via trigeminal and hand stimulation in a large group of healthy volunteers. We recorded the LEPs by right-hand stimulation in 237 healthy subjects and by stimulation of the right supraorbital zone in 170 cases. The subjects ranged in age from 7 to 72 years and were divided into six groups by age. At the trigeminal level, the N2 and P2 latencies were significantly shorter and the N2-P2 amplitude was significantly larger in the 7-17 age group than in the other groups. The N2-P2 amplitude of the responses evoked by hand stimulation was significantly larger in the 7-40 age range than in the older subjects. The N1 amplitude and latency were not significantly different among the groups. The N2-P2 habituation increased with age, but no significant changes among groups were revealed by the Bonferroni test. Trigeminal vertex LEPs have greater amplitudes and appear earlier in children, while a progressive age-related amplitude decrease characterizes the N2-P2 waves associated with hand stimulation. The N2-P2 habituation increases in older people. The N1 latency and amplitude seem to remain stable during ageing and are therefore potentially reliable and useful patterns for nociceptive system examination. Standardization of age-related changes in trigeminal and hand LEPs is possible and should improve their reliability in the objective assessment of pain pathways. © 2017 European Pain Federation - EFIC®.

Transient evoked oto-acoustic emission screening in newborns in Bogotá, Colombia: a retrospective study.

PubMed

Rojas, Jorge A; Bernal, Jaime E; García, Mary A; Zarante, Ignacio; Ramírez, Natalia; Bernal, Constanza; Gelvez, Nancy; Tamayo, Marta L

2014-10-01

The aim of this study was to investigate the characteristics and performance of transient evoked oto-acoustic emission (TEOAE) hearing screening in newborns in Colombia, and analyze all possible variables and factors affecting the results. An observational, descriptive and retrospective study with bivariate analysis was performed. The study population consisted of 56,822 newborns evaluated at the private institution, PREGEN. TEOAE testing was carried out as a pediatric hearing screening test from December 2003 to March 2012. The database from PREGEN was revised, and the protocol for evaluation included the same screening test performed twice. Demographic characteristics were recorded and the newborn's background was evaluated. Basic statistics of the qualitative and quantitative variables, and statistical analysis were obtained using the chi-square test. Of the 56,822 records examined, 0.28% were classed as abnormal, which corresponded to a prevalence of 1 in 350. In the screened newborns, 0.08% had a major abnormality or other clinical condition diagnosed, and 0.29% reported a family history of hearing loss. A prevalence of 6.7 in 10,000 was obtained for microtia, which is similar to the 6.4 in 10,000 previously reported in Colombia (database of the Latin-American Collaborative Study of Congenital Malformations - ECLAMC). Statistical analysis demonstrated an association between presenting with a major anomaly and a higher frequency of abnormal results on both TEOAE tests. Newborns in Colombia do not currently undergo screening for the early detection of hearing impairment. The results from this study suggest TEOAE screening tests, when performed twice, are able to detect hearing abnormalities in newborns. This highlights the need to improve the long-term evaluation and monitoring of patients in Colombia through diagnostic tests, and to provide tests that are both sensitive and specific. Furthermore, the use of TEOAE screening is justified by the favorable cost

An approach for brain-controlled prostheses based on Scene Graph Steady-State Visual Evoked Potentials.

PubMed

Li, Rui; Zhang, Xiaodong; Li, Hanzhe; Zhang, Liming; Lu, Zhufeng; Chen, Jiangcheng

2018-08-01

Brain control technology can restore communication between the brain and a prosthesis, and choosing a Brain-Computer Interface (BCI) paradigm to evoke electroencephalogram (EEG) signals is an essential step for developing this technology. In this paper, the Scene Graph paradigm used for controlling prostheses was proposed; this paradigm is based on Steady-State Visual Evoked Potentials (SSVEPs) regarding the Scene Graph of a subject's intention. A mathematic model was built to predict SSVEPs evoked by the proposed paradigm and a sinusoidal stimulation method was used to present the Scene Graph stimulus to elicit SSVEPs from subjects. Then, a 2-degree of freedom (2-DOF) brain-controlled prosthesis system was constructed to validate the performance of the Scene Graph-SSVEP (SG-SSVEP)-based BCI. The classification of SG-SSVEPs was detected via the Canonical Correlation Analysis (CCA) approach. To assess the efficiency of proposed BCI system, the performances of traditional SSVEP-BCI system were compared. Experimental results from six subjects suggested that the proposed system effectively enhanced the SSVEP responses, decreased the degradation of SSVEP strength and reduced the visual fatigue in comparison with the traditional SSVEP-BCI system. The average signal to noise ratio (SNR) of SG-SSVEP was 6.31 ± 2.64 dB, versus 3.38 ± 0.78 dB of traditional-SSVEP. In addition, the proposed system achieved good performances in prosthesis control. The average accuracy was 94.58% ± 7.05%, and the corresponding high information transfer rate (IRT) was 19.55 ± 3.07 bit/min. The experimental results revealed that the SG-SSVEP based BCI system achieves the good performance and improved the stability relative to the conventional approach. Copyright © 2018 Elsevier B.V. All rights reserved.

Vestibular Evoked Myogenic Potentials in Normal Mice and Phex Mice With Spontaneous Endolymphatic Hydrops

PubMed Central

Sheykholeslami, Kianoush; Megerian, Cliff A.; Zheng, Qing Y.

2010-01-01

Objective and Background Vestibular evoked myogenic potentials (VEMPs) have been recorded from the neck musculature and the cervical spinal cord in humans and a limited number of laboratory animals in response to loud sound. However, the mouse VEMP has yet to be described. Evaluation of the sacculocollic pathway via VEMPs in mice can set the stage for future evaluations of mutant mice that now play an important role in research regarding human auditory and vestibular dysfunction. Materials and Methods Sound-evoked potentials were recorded from the neck extensor muscles and the cervical spinal cord in normal adult mice and in circling PhexHyp-Duk/y mice with known vestibular abnormalities, including endolymphatic hydrops (ELH). Results Biphasic potentials were recorded from all normal animals. The mean threshold of the VEMP response in normal adult mice was 60 dB normal hearing level with a mean peak latency of 6.25 ± 0.46 and 7.95 ± 0.42 milliseconds for p1 and n1 peaks, respectively. At the maximum sound intensity used (100 dB normal hearing level), 4 of 5 Phex mice did not exhibit VEMP responses, and 1 showed an elevated threshold, but normal response, with regard to peak latency and amplitude. The histologic findings in all of these Phex mice were consistent with distended membranous labyrinth, displaced Reissner membrane, ganglion cell loss, and ELH. Conclusion This is the first report of VEMP recordings in mice and the first report of abnormal VEMPs in a mouse model with ELH. The characteristics of these potentials such as higher response threshold in comparison to auditory brainstem response, myogenic nature of the response, and latency correlation with the cervical recording (accessory nerve nucleus) were similar to those of VEMPs in humans, guinea pigs, cats, and rats, suggesting that the mouse may be used as an animal model in the study of VEMPs. The simplicity and reliability of these recordings make the VEMP a uniquely informative test for assessing

Topics in electromagnetic, acoustic, and potential scattering theory

NASA Astrophysics Data System (ADS)

Nuntaplook, Umaporn

With recent renewed interest in the classical topics of both acoustic and electromagnetic aspects for nano-technology, transformation optics, fiber optics, metamaterials with negative refractive indices, cloaking and invisibility, the topic of time-independent scattering theory in quantum mechanics is becoming a useful field to re-examine in the above contexts. One of the key areas of electromagnetic theory scattering of plane electromagnetic waves --- is based on the properties of the refractive indices in the various media. It transpires that the refractive index of a medium and the potential in quantum scattering theory are intimately related. In many cases, understanding such scattering in radially symmetric media is sufficient to gain insight into scattering in more complex media. Meeting the challenge of variable refractive indices and possibly complicated boundary conditions therefore requires accurate and efficient numerical methods, and where possible, analytic solutions to the radial equations from the governing scalar and vector wave equations (in acoustics and electromagnetic theory, respectively). Until relatively recently, researchers assumed a constant refractive index throughout the medium of interest. However, the most interesting and increasingly useful cases are those with non-constant refractive index profiles. In the majority of this dissertation the focus is on media with piecewise constant refractive indices in radially symmetric media. The method discussed is based on the solution of Maxwell's equations for scattering of plane electromagnetic waves from a dielectric (or "transparent") sphere in terms of the related Helmholtz equation. The main body of the dissertation (Chapters 2 and 3) is concerned with scattering from (i) a uniform spherical inhomogeneity embedded in an external medium with different properties, and (ii) a piecewise-uniform central inhomogeneity in the external medium. The latter results contain a natural generalization of

Visual Acuity and Contrast Sensitivity Development in Children: Sweep Visually Evoked Potential and Psychophysics.

PubMed

Almoqbel, Fahad M; Irving, Elizabeth L; Leat, Susan J

2017-08-01

The purpose of this study was to investigate the development of visual acuity (VA) and contrast sensitivity in children as measured with objective (sweep visually evoked potential) and subjective, psychophysical techniques, including signal detection theory (SDT), which attempts to control for differences in criterion or behavior between adults and children. Furthermore, this study examines the possibility of applying SDT methods with children. Visual acuity and contrast thresholds were measured in 12 children 6 to 7 years old, 10 children 8 to 9 years old, 10 children 10 to 12 years old, and 16 adults. For sweep visually evoked potential measurements, spatial frequency was swept from 1 to 40 cpd to measure VA, and contrast of sine-wave gratings (1 or 8 cpd) was swept from 0.33 to 30% to measure contrast thresholds. For psychophysical measurements, VA and contrast thresholds (1 or 8 cpd) were measured using a temporal two-alternative forced-choice staircase procedure and also with a yes-no SDT procedure. Optotype (logMAR [log of the minimum angle of resolution]) VA was also measured. The results of the various procedures were in agreement showing that there are age-related changes in threshold values and logMAR VA after the age of 6 years and that these visual functions do not become adult-like until the age of 8 to 9 years at the earliest. It was also found that children can participate in SDT procedures and do show differences in criterion compared with adults in psychophysical testing. These findings confirm a slightly later development of VA and contrast sensitivity (8 years or older) and indicate the importance of using SDT or forced-choice procedures in any developmental study to attempt to overcome the effect of criterion in children.

Brain correlates of music-evoked emotions.

PubMed

Koelsch, Stefan

2014-03-01

Music is a universal feature of human societies, partly owing to its power to evoke strong emotions and influence moods. During the past decade, the investigation of the neural correlates of music-evoked emotions has been invaluable for the understanding of human emotion. Functional neuroimaging studies on music and emotion show that music can modulate activity in brain structures that are known to be crucially involved in emotion, such as the amygdala, nucleus accumbens, hypothalamus, hippocampus, insula, cingulate cortex and orbitofrontal cortex. The potential of music to modulate activity in these structures has important implications for the use of music in the treatment of psychiatric and neurological disorders.

Intraoperative monitoring of somatosensory-evoked potential in the spinal cord rectification operation by means of wavelet analysis

NASA Astrophysics Data System (ADS)

Liu, W.; Du, M. H.; Chan, Francis H. Y.; Lam, F. K.; Luk, D. K.; Hu, Y.; Fung, Kan S. M.; Qiu, W.

1998-09-01

Recently there has been a considerable interest in the use of a somatosensory evoked potential (SEP) for monitoring the functional integrity of the spinal cord during surgery such as spinal scoliosis. This paper describes a monitoring system and signal processing algorithms, which consists of 50 Hz mains filtering and a wavelet signal analyzer. Our system allows fast detection of changes in SEP peak latency, amplitude and signal waveform, which are the main parameters of interest during intra-operative procedures.

Two Sides of the Same Coin: ERP and Wavelet Analyses of Visual Potentials Evoked and Induced by Task-Relevant Faces.

PubMed

Van der Lubbe, Rob H J; Szumska, Izabela; Fajkowska, Małgorzata

2016-01-01

New analysis techniques of the electroencephalogram (EEG) such as wavelet analysis open the possibility to address questions that may largely improve our understanding of the EEG and clarify its relation with related potentials (ER Ps). Three issues were addressed. 1) To what extent can early ERERP components be described as transient evoked oscillations in specific frequency bands? 2) Total EEG power (TP) after a stimulus consists of pre-stimulus baseline power (BP), evoked power (EP), and induced power (IP), but what are their respective contributions? 3) The Phase Reset model proposes that BP predicts EP, while the evoked model holds that BP is unrelated to EP; which model is the most valid one? EEG results on NoGo trials for 123 individuals that took part in an experiment with emotional facial expressions were examined by computing ERPs and by performing wavelet analyses on the raw EEG and on ER Ps. After performing several multiple regression analyses, we obtained the following answers. First, the P1, N1, and P2 components can by and large be described as transient oscillations in the α and θ bands. Secondly, it appears possible to estimate the separate contributions of EP, BP, and IP to TP, and importantly, the contribution of IP is mostly larger than that of EP. Finally, no strong support was obtained for either the Phase Reset or the Evoked model. Recent models are discussed that may better explain the relation between raw EEG and ERPs.

Two Sides of the Same Coin: ERP and Wavelet Analyses of Visual Potentials Evoked and Induced by Task-Relevant Faces

PubMed Central

Van der Lubbe, Rob H. J.; Szumska, Izabela; Fajkowska, Małgorzata

2016-01-01

New analysis techniques of the electroencephalogram (EEG) such as wavelet analysis open the possibility to address questions that may largely improve our understanding of the EEG and clarify its relation with related potentials (ER Ps). Three issues were addressed. 1) To what extent can early ERERP components be described as transient evoked oscillations in specific frequency bands? 2) Total EEG power (TP) after a stimulus consists of pre-stimulus baseline power (BP), evoked power (EP), and induced power (IP), but what are their respective contributions? 3) The Phase Reset model proposes that BP predicts EP, while the evoked model holds that BP is unrelated to EP; which model is the most valid one? EEG results on NoGo trials for 123 individuals that took part in an experiment with emotional facial expressions were examined by computing ERPs and by performing wavelet analyses on the raw EEG and on ER Ps. After performing several multiple regression analyses, we obtained the following answers. First, the P1, N1, and P2 components can by and large be described as transient oscillations in the α and θ bands. Secondly, it appears possible to estimate the separate contributions of EP, BP, and IP to TP, and importantly, the contribution of IP is mostly larger than that of EP. Finally, no strong support was obtained for either the Phase Reset or the Evoked model. Recent models are discussed that may better explain the relation between raw EEG and ERPs. PMID:28154612

Relationship between median nerve somatosensory evoked potentials and spinal cord injury levels in patients with quadriplegia.

PubMed

de Arruda Serra Gaspar, M I F; Cliquet, A; Fernandes Lima, V M; de Abreu, D C C

2009-05-01

Cross-sectional study. To observe if there is a relationship between the level of injury by the American Spinal Cord Injury Association (ASIA) and cortical somatosensory evoked potential (SSEP) recordings of the median nerve in patients with quadriplegia. Rehabilitation Outpatient Clinic at the university hospital in Brazil. Fourteen individuals with quadriplegia and 8 healthy individuals were evaluated. Electrophysiological assessment of the median nerve was performed by evoked potential equipment. The injury level was obtained by ASIA. N(9), N(13) and N(20) were analyzed based on the presence or absence of responses. The parameters used for analyzing these responses were the latency and the amplitude. Data were analyzed using mixed-effect models. N(9) responses were found in all patients with quadriplegia with a similar latency and amplitude observed in healthy individuals; N(13) responses were not found in any patients with quadriplegia. N(20) responses were not found in C5 patients with quadriplegia but it was present in C6 and C7 patients. Their latencies were similar to healthy individuals (P>0.05) but the amplitudes were decreased (P<0.05). This study suggests that the SSEP responses depend on the injury level, considering that the individuals with C6 and C7 injury levels, both complete and incomplete, presented SSEP recordings in the cortical area. It also showed a relationship between the level of spinal cord injury assessed by ASIA and the median nerve SSEP responses, through the latency and amplitude recordings.

Pattern Visual Evoked Potentials Elicited by Organic Electroluminescence Screen

PubMed Central

Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Funada, Hideaki; Minoda, Haruka

2014-01-01

Purpose. To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT) screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account. PMID:25197652

Middle ear muscle contractions and their relation to pulse and echo evoked potentials in the bat

NASA Technical Reports Server (NTRS)

Henson, O. W., Jr.; Henson, M. M.

1972-01-01

An analysis is made of pulse and echo orientation cries of the Mustache Bat. That bat's cries are characterized by a long, 60 to 30 msec, pure tone component and brief beginning and terminal FM sweeps. In addition to obvious echo overlap and middle ear muscle contractions, the following are examined: (1) characteristics of pulse- and echo-evoked potential under various conditions, (2) evidence of changes in hearing sensitivity during and after pulse emission, and (3) the role of the middle ear muscles in bringing about these changes.

Cortical auditory evoked potentials in the assessment of auditory neuropathy: two case studies.

PubMed

Pearce, Wendy; Golding, Maryanne; Dillon, Harvey

2007-05-01

Infants with auditory neuropathy and possible hearing impairment are being identified at very young ages through the implementation of hearing screening programs. The diagnosis is commonly based on evidence of normal cochlear function but abnormal brainstem function. This lack of normal brainstem function is highly problematic when prescribing amplification in young infants because prescriptive formulae require the input of hearing thresholds that are normally estimated from auditory brainstem responses to tonal stimuli. Without this information, there is great uncertainty surrounding the final fitting. Cortical auditory evoked potentials may, however, still be evident and reliably recorded to speech stimuli presented at conversational levels. The case studies of two infants are presented that demonstrate how these higher order electrophysiological responses may be utilized in the audiological management of some infants with auditory neuropathy.

Cochlear Microphonic and Summating Potential Responses from Click-Evoked Auditory Brain Stem Responses in High-Risk and Normal Infants.

PubMed

Hunter, Lisa L; Blankenship, Chelsea M; Gunter, Rebekah G; Keefe, Douglas H; Feeney, M Patrick; Brown, David K; Baroch, Kelly

2018-05-01

Examination of cochlear and neural potentials is necessary to assess sensory and neural status in infants, especially those cared for in neonatal intensive care units (NICU) who have high rates of hyperbilirubinemia and thus are at risk for auditory neuropathy (AN). The purpose of this study was to determine whether recording parameters commonly used in click-evoked auditory brain stem response (ABR) are useful for recording cochlear microphonic (CM) and Wave I in infants at risk for AN. Specifically, we analyzed CM, summating potential (SP), and Waves I, III, and V. The overall aim was to compare latencies and amplitudes of evoked responses in infants cared for in NICUs with infants in a well-baby nursery (WBN), both of which passed newborn hearing screening. This is a prospective study in which infants who passed ABR newborn hearing screening were grouped based on their birth history (WBN and NICU). All infants had normal hearing status when tested with diagnostic ABR at about one month of age, corrected for prematurity. Thirty infants (53 ears) from the WBN [mean corrected age at test = 5.0 weeks (wks.)] and thirty-two infants (59 ears) from the NICU (mean corrected age at test = 5.7 wks.) with normal hearing were included in this study. In addition, two infants were included as comparative case studies, one that was diagnosed with AN and another case that was diagnosed with bilateral sensorineural hearing loss (SNHL). Diagnostic ABR, including click and tone-burst air- and bone-conduction stimuli were recorded. Peak Waves I, III, and V; SP; and CM latency and amplitude (peak to trough) were measured to determine if there were differences in ABR and electrocochleography (ECochG) variables between WBN and NICU infants. No significant group differences were found between WBN and NICU groups for ABR waveforms, CM, or SP, including amplitude and latency values. The majority (75%) of the NICU group had hyperbilirubinemia, but overall, they did not show evidence of

Auditory evoked potentials to abrupt pitch and timbre change of complex tones: electrophysiological evidence of 'streaming'?

PubMed

Jones, S J; Longe, O; Vaz Pato, M

1998-03-01

Examination of the cortical auditory evoked potentials to complex tones changing in pitch and timbre suggests a useful new method for investigating higher auditory processes, in particular those concerned with 'streaming' and auditory object formation. The main conclusions were: (i) the N1 evoked by a sudden change in pitch or timbre was more posteriorly distributed than the N1 at the onset of the tone, indicating at least partial segregation of the neuronal populations responsive to sound onset and spectral change; (ii) the T-complex was consistently larger over the right hemisphere, consistent with clinical and PET evidence for particular involvement of the right temporal lobe in the processing of timbral and musical material; (iii) responses to timbral change were relatively unaffected by increasing the rate of interspersed changes in pitch, suggesting a mechanism for detecting the onset of a new voice in a constantly modulated sound stream; (iv) responses to onset, offset and pitch change of complex tones were relatively unaffected by interfering tones when the latter were of a different timbre, suggesting these responses must be generated subsequent to auditory stream segregation.

Face-Evoked Steady-State Visual Potentials: Effects of Presentation Rate and Face Inversion

PubMed Central

Gruss, L. Forest; Wieser, Matthias J.; Schweinberger, Stefan R.; Keil, Andreas

2012-01-01

Face processing can be explored using electrophysiological methods. Research with event-related potentials has demonstrated the so-called face inversion effect, in which the N170 component is enhanced in amplitude and latency to inverted, compared to upright, faces. The present study explored the extent to which repetitive lower-level visual cortical engagement, reflected in flicker steady-state visual evoked potentials (ssVEPs), shows similar amplitude enhancement to face inversion. We also asked if inversion-related ssVEP modulation would be dependent on the stimulation rate at which upright and inverted faces were flickered. To this end, multiple tagging frequencies were used (5, 10, 15, and 20 Hz) across two studies (n = 21, n = 18). Results showed that amplitude enhancement of the ssVEP for inverted faces was found solely at higher stimulation frequencies (15 and 20 Hz). By contrast, lower frequency ssVEPs did not show this inversion effect. These findings suggest that stimulation frequency affects the sensitivity of ssVEPs to face inversion. PMID:23205009