Note: This page contains sample records for the topic brainstem evoked potentials from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Brainstem evoked potentials in adult sleep apnea.  

PubMed

Brainstem evoked potentials (BSEP) were recorded in 23 patients with adult sleep apnea (ASA). Three patients were studied with all-night polysomnography prior to our testing. They were categorized as having obstructive, central, or mixed sleep apnea depending on the predominant sleep findings. All patients with central sleep apnea had abnormal BSEP with prolongation of wave V. A majority of the remaining patients with obstructive sleep apnea and mixed sleep apnea had abnormal BSEP, but without specific configurations. These findings substantiate our hypothesis that brainstem dysfunction may play a role in ASA. PMID:7149540

Snyderman, N L; Johnson, J T; Møller, M; Thearle, P B

2

Brainstem evoked potentials in panic disorder.  

PubMed Central

Patient reports and laboratory tests support the notion that panic attacks are generated by stimulation of brainstem nuclei. Scalp-recorded brainstem auditory evoked potentials may serve as a unique measurement strategy for the noninvasive assessment of the role of brainstem functioning in panic disorder. Ipsilateral and contralateral BSAEP recordings were examined in response to separate left and right ear click stimulation in 28 patients with a diagnosis of panic disorder and in 18 normal controls. Latency measures did not differentiate between the patient and control groups but amplitudes of wave III and V were found to be larger in patients. These findings are discussed in relation to pathophysiological and neurochemical theories of panic and specific emphasis is placed on serotonergic function.

Knott, V J; Bakish, D; Barkley, J

1994-01-01

3

Brainstem auditory and visual evoked potentials in infants with myelomeningocele  

Microsoft Academic Search

Brainstem auditory evoked potentials (BAEPs) and visual evoked potentials WEN were recorded in 47 infants with myelomeningocele to determine if the evoked potentials reflected the early neurological status, and if they had prognostic value as to the children's neurological outcome. The infants were tested between 1 day and 3 months of age (mean 24 days), while still in hospital after

Margot J. Taylor; Rainer Boor; Nancy K. Keenan; James T. Rutka; James M. Drake

1996-01-01

4

Air pollution is associated with brainstem auditory nuclei pathology and delayed brainstem auditory evoked potentials  

Microsoft Academic Search

We assessed brainstem inflammation in children exposed to air pollutants by comparing brainstem auditory evoked potentials (BAEPs) and blood inflammatory markers in children age 96.3±8.5 months from highly polluted (n=34) versus a low polluted city (n=17). The brainstems of nine children with accidental deaths were also examined. Children from the highly polluted environment had significant delays in wave III (t(50)=17.038;

Lilian Calderón-Garcidueñas; Amedeo D’Angiulli; Randy J. Kulesza; Ricardo Torres-Jardón; Norma Osnaya; Lina Romero; Sheyla Keefe; Lou Herritt; Diane M. Brooks; Jose Avila-Ramirez; Ricardo Delgado-Chávez; Humberto Medina-Cortina; Luis Oscar González-González

2011-01-01

5

Brain-stem auditory evoked potentials in children with brain-stem or cerebellar dysfunction.  

PubMed

Brain-stem auditory evoked potentials (BAEPs) were recorded in 23 children who had signs of brain-stem or cerebellar dysfunction. In patients with brain-stem gliomas, BAEPs were abnormal in all except one, in whom involvement of the brain-stem auditory pathway was limited to the midbrain tectum. The BAEPs were normal in neuronal ceroid lipofuscinosis, but abnormal bilaterally in inheritable leukoencephalopathies. All patients with Leigh's encephalopathy had BAEP abnormalities; in two, abnormalities occurred before the appearance of lesions on computed tomographic scan. Patients with Friedreich's ataxia and giant axonal dystrophy had abnormal BAEPs, but the test was normal in a child with similar neurologic findings with vitamin E deficiency. Patients with diffuse metabolic encephalopathies had variable findings. Thus, BAEP abnormalities are nonspecific for various disease processes but are frequently seen in neoplastic and neurodegenerative diseases, with primary white matter or extensive brain-stem involvement. PMID:3977645

Davis, S L; Aminoff, M J; Berg, B O

1985-02-01

6

Reliability of Brainstem Auditory Evoked Potentials (BAEP) Using the Nicolet Pathfinder II.  

National Technical Information Service (NTIS)

Evoked potentials (EP) are emerging as a useful diagnostic tool to determine the functional integrity of the central and peripheral nervous systems. The Brainstem Auditory Evoked Potential (BAEP) provides a rapid assessment of the functioning of the brain...

D. J. McMenemy T. M. Rauch W. J. Tharion

1989-01-01

7

Brain-stem evoked potentials and noise effects in seagulls.  

PubMed

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. PMID:2863073

Counter, S A

1985-01-01

8

Air pollution is associated with brainstem auditory nuclei pathology and delayed brainstem auditory evoked potentials  

PubMed Central

We assessed brainstem inflammation in children exposed to air pollutants by comparing brainstem auditory evoked potentials (BAEPs) and blood inflammatory markers in children age 96.3± 8.5 months from highly polluted (n=34) versus a low polluted city (n=17). The brainstems of nine children with accidental deaths were also examined. Children from the highly polluted environment had significant delays in wave III (t(50)=17.038; p<0.0001) and wave V (t(50)=19.730; p<0.0001) but no delay in wave I (p=0.548). They also had significantly longer latencies than controls for interwave intervals I–III, III–V, and I–V (all t(50)> 7.501; p<0.0001), consisting with delayed central conduction time of brainstem neural transmission. Highly exposed children showed significant evidence of inflammatory markers and their auditory and vestibular nuclei accumulated ? synuclein and/or ? amyloid 1–42. Medial superior olive neurons, critically involved in BAEPs, displayed significant pathology. Children’s exposure to urban air pollution increases their risk for auditory and vestibular impairment.

Calderon-Garciduenas, Lilian; D'Angiulli, Amedeo; Kulesza, Randy J; Torres-Jardon, Ricardo; Osnaya, Norma; Romero, Lina; Keefe, Sheyla; Herritt, Lou; Brooks, Diane M; Avila-Ramirez, Jose; Delgado-Chavez, Ricardo; Medina-Cortina, Humberto; Gonzalez-Gonzalez, Luis Oscar

2011-01-01

9

Brainstem auditory evoked potentials and middle latency auditory evoked potentials in young children.  

PubMed

Measurements of brainstem auditory evoked potentials (BAEP) and middle latency auditory evoked potentials (MLAEP) are readily available neurophysiologic assessments. The generators for BAEP are believed to involve the structures of cochlear nerve, cochlear nucleus, superior olive complex, dorsal and rostral pons, and lateral lemniscus. The generators for MLAEP are assumed to be located in the subcortical area and auditory cortex. BAEP are commonly used in evaluating children with autistic and hearing disorders. However, measurement of MLAEP is rarely performed in young children. To explore the feasibility of this procedure in young children, we retrospectively reviewed our neurophysiology databank and charts for a 3-year period to identify subjects who had both BAEP and MLAEP performed. Subjects with known or identifiable central nervous system abnormalities from the history, neurologic examination and neuroimaging studies were excluded. This cohort of 93 children up to 3 years of age was divided into 10 groups based on the age at testing (upper limits of: 1 week; 1, 2, 4, 6, 8, 10 and 12 months; 2 years; and 3 years of age). Evolution of peak latency, interpeak latency and amplitude of waveforms in BAEP and MLAEP were demonstrated. We concluded that measurement of BAEP and MLAEP is feasible in children, as early as the first few months of life. The combination of both MLAEP and BAEP may increase the diagnostic sensitivity of neurophysiologic assessment of the integrity or functional status of both the peripheral (acoustic nerve) and the central (brainstem, subcortical and cortical) auditory conduction systems in young children with developmental speech and language disorders. PMID:23266312

Luo, Jin Jun; Khurana, Divya S; Kothare, Sanjeev V

2012-12-21

10

Preliminary Processing and Detection of Characteristic Features of Brainstem Auditory Evoked Potentials (BAEP).  

National Technical Information Service (NTIS)

The Brainstem Auditory Evoked Potentials (BAEP) provide an objective, electrophysiological diagnostic method, widely applied in examinations of auditory organs, in particular for such cases, when the application of traditional audiometric methods is diffi...

I. Wochlik J. Bulka A. Izworski A. Paslawski

2001-01-01

11

Delayed brainstem auditory evoked potential latencies in 14-year-old children exposed to methylmercury  

Microsoft Academic Search

ObjectiveTo determine possible exposure-associated delays in auditory brainstem evoked potential latencies as an objective measure of neurobehavioral toxicity in 14-year-old children with developmental exposure to methylmercury (MeHg) from seafood.

Katsuyuki Murata; Pál Weihe; Esben Budtz-Jørgensen; Poul J Jørgensen; Philippe Grandjean

2004-01-01

12

The brainstem auditory evoked potentials estimation using a Bayesian deconvolution method  

Microsoft Academic Search

This paper presents a new approach for estimating the Brainstem Auditory Evoked Potentials (BAEP). The originality of this method is that it is not content only on the observation defined as the response to the stimulation, but integrates also information about the stimulus and the Evoked Potentials (EPs) properties. The authors model the physiological system by a linear one and

Amine M. NAIT-ALI; Olivier ADAM; Jean-Franqois MOTSCH

1996-01-01

13

Clinical study of vestibular-evoked myogenic potentials and auditory brainstem responses in patients with brainstem lesions.  

PubMed

A total of 13 patients, who were diagnosed with localized brainstem lesions using MRI, were investigated. The diagnoses were multiple sclerosis in five patients, brainstem hemorrhage in three patients, pontomedullary infarction in one patient and Wallenberg's syndrome in four patients. In addition, 42 ears of 21 normal adult volunteers were also examined. In a patient with upper brainstem lesions mainly affecting the midbrain, the auditory brainstem response (ABR) was abnormal but the vestibular-evoked myogenic potential (VEMP) was normal. In four patients with middle brainstem lesions which mainly affected the pons, both ABR and VEMP were abnormal. In five patients with lower brainstem lesions which mainly affected the medulla, the ABR was normal but the VEMP was abnormal. In those patients with middle-to-lower brainstem lesions, a disappearance of VEMP reactions, delay of the positive-negative (PN) wave, increase in PN interpeak latency and decrease in PN amplitude on the affected side were confirmed. In conclusion, the VEMP test comprises a useful new diagnostic method for identifying lower brainstem lesions. PMID:11677723

Itoh, A; Kim, Y S; Yoshioka, K; Kanaya, M; Enomoto, H; Hiraiwa, F; Mizuno, M

2001-01-01

14

Brainstem auditory evoked potentials in syndromes of decerebration, the bulbar syndrome and in central death  

Microsoft Academic Search

The results are reported of serial brainstem auditory evoked potentials recordings in 51 patients with decerebration and bulbar syndrome. In contrast to the stability of latencies of single components of the potential in healthy subjects, patients with decerebration syndromes show considerable instability and an increase in the latency of all the components of the potential. In 34 decerebrate patients the

N. Klug

1982-01-01

15

Utility of somatosensory evoked potentials in the early diagnosis of Bickerstaff's brainstem encephalitis  

Microsoft Academic Search

Bickerstaff's brainstem encephalitis (BBE) is characterized by diverse symptoms, and early diagnosis is often difficult, especially confusing with menigoencephalitis with cranial nerve involvements. Diagnostic role of anti-GQ1b antibody has been established, although its result is usually known late. Prompt diagnosis is preferred because immunotherapies are effective. Here we illustrate the usefulness of somatosensory evoked potentials (SEP) in the early diagnosis

H. Tsukamoto; M Sonoo; Y. Hatanaka; M. Kobayashi; T. Shimizu

2005-01-01

16

Brainstem auditory evoked potential recording in patients with epilepsy.  

PubMed

The brain stem auditory evoked potential (BSAEP) was recorded in 32 normal control subjects and 81 epileptic patients. Statistically significant differences in regard to sex and laterality of ear stimulated were found to exist in both groups. The epileptic patients also had significantly longer latencies for all wave components and interwaves I-III as well as I-IV than the normal controls. There were no differences in regard to interwave latency III-V. Clinically significant latency prolongations (more than three standard deviations from the norm) were encountered especially in regard to waves I and III. Correlations of wave and interwave latencies with a large variety of clinical variables showed that statistically significant relationships existed mainly in regard to presence or absence of brain damage and the severity of the seizure disorder, as expressed by the number of different seizure types to which a given patient was subject. Waves II and III showed the most consistent latency prolongations for these variables. Anticonvulsant medication levels did affect wave latencies, but apart from Primidone, it involved waves IV through VII rather than II and III. Carbamazepine levels were related to prolongation of I-III interwave latency. It is concluded that severely brain-damaged epileptic patients have demonstrable brain stem dysfunction affecting mainly the medullo-pontine rather than midbrain or thalamic structures. PMID:7127849

Rodin, E; Chayasirisobhon, S; Klutke, G

1982-07-01

17

Somatosensory and brainstem auditory evoked potential in congenital craniovertebral anomaly; effect of surgical management.  

PubMed Central

Clinical features and evoked potential recordings were analysed in 32 patients with congenital atlantoaxial dislocation before and after surgery. Seven patients (group 1) had atlantoaxial dislocation, while 22 patients had associated basilar invagination (group 2). In both groups, pyramidal tract signs, posterior column signs, wasting of the upper limbs, and abnormality of somatosensory evoked potentials (SSEP) were similar. Conversely, lower cranial nerve involvement and abnormal brainstem auditory evoked potentials (BAEP) were significantly more in patients with basilar invagination (p less than 0.05). All seven patients in group 1 and 17 patients in group 2 were operated upon. Clinical and electrophysiological deterioration were significant in patients with basilar invagination (group 2), following posterior fixation compared with group 1. Among the patients in group 2, who clinically deteriorated following posterior fixation, seven had transoral excision of odontoid and six of them improved both clinically and electrophysiologically. Two patients in group 2 had odontoid excision before posterior fixation, and in both the evoked potentials improved postoperatively. In group 1 the patient's BAEP remained unaffected following posterior fixation, however, in group 2, eight patients over 53% showed improvement in brainstem function following posterior fixation. This study shows the value of evoked potentials in congenital atlantoaxial dislocation, and rationalizes the surgical procedure in these patients. In patients with basilar invagination, odontoid excision is the preferred first stage procedure. Images

Sood, S; Mahapatra, A K; Bhatia, R

1992-01-01

18

Vestibular evoked myogenic potentials in acoustic tumor patients with normal auditory brainstem responses  

Microsoft Academic Search

In order to clarify the utility of the vestibular evoked myogenic potential (VEMP) in detecting acoustic tumors, we report\\u000a two patients who were found to have normal auditory brainstem responses (ABRs) and abnormal VEMPs. To record VEMPs, electromyographic\\u000a responses to brief loud clicks (0.1 ms at 95 dBnHL) were amplified and averaged on the sternocleidomastoid muscle ipsilateral\\u000a to the stimulated

M. Matsuzaki; T. Murofushi; M. Mizuno

1999-01-01

19

Brainstem and middle latency auditory evoked potentials in autism and developmental language disorder  

Microsoft Academic Search

Brainstem auditory evoked potentials (BAEP) and middle latency responses (MLR) were studied in 8 nonretarded subjects with infantile autism (mean age=23.3,SD=2.8), 8 subjects with receptive developmental language disorder (mean age=16.3,SD=1.4), and normal control subjects matched to each group for age, gender, and Performance IQ. Click stimuli were delivered monaurally to the left and the right ear and binaurally for both

Christian Grillon; Eric Courchesne; Natacha Akshoomoff

1989-01-01

20

Brainstem auditory evoked potentials in syndromes of decerebration, the bulbar syndrome and in central death.  

PubMed

The results are reported of serial brainstem auditory evoked potentials recordings in 51 patients with decerebration and bulbar syndrome. In contrast to the stability of latencies of single components of the potential in healthy subjects, patients with decerebration syndromes show considerable instability and an increase in the latency of all the components of the potential. In 34 decerebrate patients the P-I latency and the interpeak latencies for the medullo-pontine and ponto-mesencephalic segments as well as the central conduction time were significantly increased. There was marked reduction of the amplitude of P-V and P-III and deformation of the single components of the potential with widening and smoothing. The amplitude ratios A-V to A-I and A-III to A-I were significantly decreased. The findings are interpreted as due to mesencephalic and pontine functional disturbance during decerebration. The brainstem auditory evoked potential can be used to estimate the time of brain death. Possible causes of misinterpretation are discussed. PMID:6183408

Klug, N

1982-01-01

21

Effects of low pass filtering on the brainstem auditory evoked potential in the rat.  

PubMed

The effects of low pass filtering on the brainstem auditory evoked potential (BAEP) were studied in the adult male rat. The bandpass of the recording system was progressively widened while the cut-off frequency of the high pass filter remained constant at 3.2 Hz. When the high frequency cut-off was 320 Hz or less, the principal waveform recorded in response to a click stimulus was a slow positive-negative complex. As the high frequency setting was raised from 800 Hz to 3.2 kHz, the slow components of the brainstem were replaced by four fast BAEP waves (I, II, III and IV). As the bandpass widened there was an increase in amplitude and a decrease in the absolute latency of all four fast waves in the order of 0.1 ms although the wave I-IV interpeak latency remained unaffected. The results confirm that the high frequency components of the BAEP are underlain by a slow positivity of uncertain origin followed by a slow negativity which probably arises within the inferior colliculus. PMID:3556497

Shaw, N A

1987-01-01

22

Sound lateralization, brainstem auditory evoked potentials and magnetic resonance imaging in multiple sclerosis.  

PubMed

Two tests of binaural hearing, namely intensity discrimination of alternating monaural clicks and interaural time difference (IATD) discrimination of binaural clicks, were performed in 28 patients with definite multiple sclerosis (MS) and 12 with an isolated brainstem lesion compatible with demyelination. Intensity discrimination defects were found in 53.5% and IATD defects in 82% of definite MS cases, although no overt auditory symptoms were reported and pure tone audiology was unremarkable. Corresponding figures in the isolated lesion group were 25% and 33%. Defects were manifested either by an abnormal 'bias' in favour of one ear or by a broadened 'spread' of responses (i.e., greater range of uncertainty). Brainstem auditory evoked potentials (BAEPs) were abnormal in 75% of the definite MS cases but only in 8% of the isolated lesion group. BAEP abnormalities involving component III on one or both sides were invariably associated with a defect of IATD discrimination. This is consistent with disruption of input to the superior olivary complex, the most peripheral structure where binaurally responsive units are sensitive to IATD. Lesions causing abnormality of component V alone less frequently resulted in impaired IATD discrimination, possibly because at rostral levels the IATD is encoded by the location rather than the timing of neuronal activity. In magnetic resonance imaging (MRI), abnormalities of the medulla, pons or midbrain were demonstrated in all MS patients tested and 45% of those with isolated brainstem lesions. The correlation with BAEP abnormalities was plausible in some patients but apparently anomalous in others. More severe BAEP abnormalities than would have been expected on the basis of MRI may have been due to small unresolved lesions, while the more frequent finding of normal or mildly abnormal BAEPs in conjunction with extensive MRI abnormalities may have been due to the fact that areas of abnormal signal reflect an increase in the water content of the tissue rather than demyelination per se. PMID:3208066

van der Poel, J C; Jones, S J; Miller, D H

1988-12-01

23

Brainstem lesion in benign paroxysmal vertigo children: Evaluated by a combined ocular and cervical vestibular-evoked myogenic potential test  

Microsoft Academic Search

ObjectiveThis study utilized a combined ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) test in children with benign paroxysmal vertigo (BPV) to investigate whether the upper or lower brainstem is more frequently affected in BPV children.

Kuei-You Lin; Ying-Shuo Hsu; Yi-Ho Young

2010-01-01

24

Localization of Brainstem Auditory Evoked Potentials in Primates: A Comparison of Localization Techniques Applied to Deep Brain Sources  

Microsoft Academic Search

The objective of this study was to evaluate the performance of source localization techniques through localization of deep brain sources. To accomplish this, two replications of a brainstem auditory evoked potential (BAEP, left ear 60 dB nHL clicks) were recorded from five normal rhesus monkeys. We analyzed waves III and IV, as this portion of the BAEP corresponds to the

Joel B. Fontanarosa; Robert E. Lasky; Hyong C. Lee; Wim van Drongelen

2004-01-01

25

Brainstem auditory evoked potentials in a case of 'Manto syndrome', or spasmodic torticollis with thoracic outlet syndrome.  

PubMed

A case of spasmodic torticollis with thoracic outlet syndrome observed for over 18 months is presented and discussed. Maximal head rotation (determining backward gaze) was associated with compression of the brachial plexus between the scaleni muscles and motor, sensory and trophic troubles in the hand. This new syndrome is called after the diviner Manto, quoted by Dante Alighieri in his 'Divina Commedia' (Inferno, XX, 52-56). The etiology was ascribed to subacute toxic effects of methylparathion. Brainstem Auditory Evoked Potentials (BAEPs) demonstrated severe brainstem involvement, maximal in the mesencephalic structures. Clinical and neurophysiological data improved on treatment with L-5-hydroxytryptophan. Finally, BAEPs returned to normal. PMID:6984700

Disertori, B; Ducati, A; Piazza, M; Pavani, M

1982-12-01

26

Localization of brainstem auditory evoked potentials in primates: a comparison of localization techniques applied to deep brain sources.  

PubMed

The objective of this study was to evaluate the performance of source localization techniques through localization of deep brain sources. To accomplish this, two replications of a brainstem auditory evoked potential (BAEP, left ear 60 dB nHL clicks) were recorded from five normal rhesus monkeys. We analyzed waves III and IV, as this portion of the BAEP corresponds to the deepest signal. Data were analyzed using five different source localization techniques: Moving Dipoles, Fixed Dipoles, MUSIC (Multiple Signal Classification) dipole scan, LORETA (Low Resolution Tomography), and LCMV (Linearly Constrained Minimum Variance) spatial filtering. The moving dipole, fixed dipole and MUSIC solutions were found to be, on average, 25.1 mm from the brainstem generators. LORETA detected sources within the brainstem 65% of the time. However, 90% of these localization results also included false detections defined as regions of the brain that were more than 2 cm away from the auditory pathway. LCMV included the brainstem in 90% of the trials and false detections in 40% of the cases. These findings indicate that evoked electrical activity from deep brain sources can be localized with cm accuracy. The dipole methods performed better than LORETA and LCMV. Given the depth and amplitude of the sources analyzed in this study, these results can be interpreted as an upper bound on the accuracy of each technique. PMID:15754875

Fontanarosa, Joel B; Lasky, Robert E; Lee, Hyong C; van Drongelen, Wim

2004-01-01

27

Brainstem auditory evoked potentials suggest a role for the ventral cochlear nucleus in tinnitus.  

PubMed

Numerous studies have demonstrated elevated spontaneous and sound-evoked brainstem activity in animal models of tinnitus, but data on brainstem function in people with this common clinical condition are sparse. Here, auditory nerve and brainstem function in response to sound was assessed via auditory brainstem responses (ABR) in humans with tinnitus and without. Tinnitus subjects showed reduced wave I amplitude (indicating reduced auditory nerve activity) but enhanced wave V (reflecting elevated input to the inferior colliculi) compared with non-tinnitus subjects matched in age, sex, and pure-tone threshold. The transformation from reduced peripheral activity to central hyperactivity in the tinnitus group was especially apparent in the V/I and III/I amplitude ratios. Compared with a third cohort of younger, non-tinnitus subjects, both tinnitus, and matched, non-tinnitus groups showed elevated thresholds above 4 kHz and reduced wave I amplitude, indicating that the differences between tinnitus and matched non-tinnitus subjects occurred against a backdrop of shared peripheral dysfunction that, while not tinnitus specific, cannot be discounted as a factor in tinnitus development. Animal lesion and human neuroanatomical data combine to indicate that waves III and V in humans reflect activity in a pathway originating in the ventral cochlear nucleus (VCN) and with spherical bushy cells (SBC) in particular. We conclude that the elevated III/I and V/I amplitude ratios in tinnitus subjects reflect disproportionately high activity in the SBC pathway for a given amount of peripheral input. The results imply a role for the VCN in tinnitus and suggest the SBC pathway as a target for tinnitus treatment. PMID:22869301

Gu, Jianwen Wendy; Herrmann, Barbara S; Levine, Robert A; Melcher, Jennifer R

2012-08-07

28

Comparison of electrically evoked whole-nerve action potential and electrically evoked auditory brainstem response thresholds in nucleus CI24R cochlear implant recipients.  

PubMed

In this study, differences between electrically evoked whole-nerve action potential (EAP) and electrically evoked auditory brainstem response (EABR) measurements within Nucleus CI24R cochlear implant recipients were evaluated. Precurved modiolus-hugging internal electrode arrays, such as the CI24R, are designed to provide more direct stimulation of neural elements of the modiolus. If the electrode array is closer to the modiolus, electrically evoked and behavioral levels might be lower than were previously recorded for the straight electrode array, the CI24M. EAP and EABR growth functions and behavioral levels were obtained for 10 postlingually deafened adults. Results revealed no significant differences between EAP and EABR threshold levels, and these levels were not significantly lower than those obtained using the CI24M. PMID:12371659

Hay-McCutcheon, Marcia J; Brown, Carolyn J; Clay, Kelly Schmidt; Seyle, Keely

2002-09-01

29

Inhalational exposure to carbonyl sulfide produces altered brainstem auditory and somatosensory-evoked potentials in Fischer 344N rats.  

PubMed

Carbonyl sulfide (COS), a chemical listed by the original Clean Air Act, was tested for neurotoxicity by a National Institute of Environmental Health Sciences/National Toxicology Program and U.S. Environmental Protection Agency collaborative investigation. Previous studies demonstrated that COS produced cortical and brainstem lesions and altered auditory neurophysiological responses to click stimuli. This paper reports the results of expanded neurophysiological examinations that were an integral part of the previously published experiments (Morgan et al., 2004, Toxicol. Appl. Pharmacol. 200, 131-145; Sills et al., 2004, Toxicol. Pathol. 32, 1-10). Fisher 334N rats were exposed to 0, 200, 300, or 400 ppm COS for 6 h/day, 5 days/week for 12 weeks, or to 0, 300, or 400 ppm COS for 2 weeks using whole-body inhalation chambers. After treatment, the animals were studied using neurophysiological tests to examine: peripheral nerve function, somatosensory-evoked potentials (SEPs) (tail/hindlimb and facial cortical regions), brainstem auditory-evoked responses (BAERs), and visual flash-evoked potentials (2-week study). Additionally, the animals exposed for 2 weeks were examined using a functional observational battery (FOB) and response modification audiometry (RMA). Peripheral nerve function was not altered for any exposure scenario. Likewise, amplitudes of SEPs recorded from the cerebellum were not altered by treatment with COS. In contrast, amplitudes and latencies of SEPs recorded from cortical areas were altered after 12-week exposure to 400 ppm COS. The SEP waveforms were changed to a greater extent after forelimb stimulation than tail stimulation in the 2-week study. The most consistent findings were decreased amplitudes of BAER peaks associated with brainstem regions after exposure to 400 ppm COS. Additional BAER peaks were affected after 12 weeks, compared to 2 weeks of treatment, indicating that additional regions of the brainstem were damaged with longer exposures. The changes in BAERs were observed in the absence of altered auditory responsiveness in FOB or RMA. This series of experiments demonstrates that COS produces changes in brainstem auditory and cortical somatosensory neurophysiological responses that correlate with previously described histopathological damage. PMID:17079700

Herr, David W; Graff, Jaimie E; Moser, Virginia C; Crofton, Kevin M; Little, Peter B; Morgan, Daniel L; Sills, Robert C

2006-11-01

30

[Prognostic evaluation of patients with severe head injury by motor evoked potentials induced by transcranial magnetic stimulation--combined analysis with brainstem auditory evoked potentials].  

PubMed

Prognostic evaluation of severe head injury was performed on the basis of transcranial magnetic motor evoked potentials (MEPs) and brainstem auditory evoked potentials (BAEPs). The subjects were 43 severe head injury patients with Glasgow Coma Scale Scores (GCS) of 9 or less. MEPs were recorded within 3 days after the injury. Patient outcome at 1, 6 and 12 months after the injury was correlated with the MEPs and BAEPs. Differences between MEP and BAEP findings in focal lesions and diffuse lesions also were analyzed. MEP wave latencies and inter-peak latencies between BAEP waves IV and V and between waves I and V were evaluated. There was a closer relationship between MEP latency and GOS, especially between the good recovery group and other outcome groups. At 1 month after the injury, there was a closer correlation between MEP latency and BAEP latency in those who died than in those who survived, and this tendency was more evident with regard to focal lesions. However, there was no significant correlation between MEP and patient outcome when the lesions were diffuse. There was no correlation between BAEP latencies and patient outcome, but there was a good, close correlation between prolonged MEP latency and unfavorable outcome at 1, 6, 12 months after injury. In conclusion, the combined use of BAEPs and MEPs induced by transcranial magnetic stimulation is useful in prognostic evaluation of acute head injury patients, especially when the brain lesions are focal. PMID:7786626

Kaneko, M

1995-05-01

31

Normative Bilateral Brainstem Evoked Response Data for a Naval Aviation Student Population: Group Statistics.  

National Technical Information Service (NTIS)

A biomedical instrumentation capability has been developed and exploratory research has been initiated to investigate the potential contributions of brainstem auditory evoked response technology to aviation medicine. Brainstem data based upon simultaneous...

W. C. Hixson J. D. Mosko

1979-01-01

32

Human brainstem auditory-evoked potentials in deep experimental diving to pressures up to 62.5 bar.  

PubMed

The neural mechanisms underlying the high pressure neurologic syndrome (HPNS), which limit man's safe advance to extreme diving depths, are still unclear. This work was aimed at a better understanding of HPNS through study of brainstem auditory-evoked potentials (BAEP). BAEP were repeatedly recorded within 2 experimental chamber dives, Titan VIII (2 divers, maximum depth of 560 msw, compression time to bottom 109 h) and Titan XI (3 divers, maximum depth of 615 msw, compression time to bottom 240 h). Prolongation of the IV/V-complex occurred in 2 divers upon reaching 525 msw during Titan VIII compression and was accompanied by vestibular disturbances and amplitude increases of finger tremor. Both categories of changes--clinical signs and IV/V delay--gradually diminished during a 4-day stay at 545 msw, suggesting that they depended on excessive compression rates and insufficient acclimation time. Longer holding times at intermittent depths during Titan XI clearly reduced both HPNS symptoms and magnitude of prolongation of IV/V latencies. Wave I and wave III latency did not significantly change, pointing to a suppression of pontomesencephalic transmission. We infer that pressure suppresses synaptic transmission or triggers an increase of cortical or subcortical efferent inhibitory modulation of upper pontine and midbrain auditory afferents. Postdive controls revealed no persistent changes of BAEP measures in either the Titan VIII or XI divers. PMID:1355311

Lorenz, J; Athanassenas, G; Hampe, P; Plath, G; Wenzel, J

1992-09-01

33

The effect of sound level, temperature and dehydration on the brainstem auditory evoked potential in anuran amphibians.  

PubMed

Brainstem auditory evoked potentials (BAEPs) were used to examine the effects of sound level, temperature, and dehydration on the auditory pathway of three species of anuran amphibians: Rana pipiens, Bufo americanus and B. terrestris. BAEP latency, amplitude and a measure of threshold were determined for all stimulus and test conditions. Threshold values obtained with this technique were similar to other neural measures of threshold in anurans, and were stable for repeated measures within 12 h and over three days. Transient changes in temperature caused non-linear changes in BAEP threshold and latency. Above 20 degrees C small threshold shifts were elicited, while below 20 degrees C we observed rapid deterioration of threshold. Animals acclimated to a cold temperature (14 degrees C) were acoustically less sensitive than warm (21 degrees C) animals, even when both groups were tested at colder temperatures. Because peripheral components of the BAEP were most affected by both transient and acclimation (longer term) cooling and warming, the sensory epithelium appears to be the most temperature-sensitive component of the auditory pathway. Dehydrated frogs showed no auditory dysfunction until a critical level of dehydration was reached. More dehydration-resistant species (B. terrestris and B. americanus) were less susceptible to BAEP degradation near their critical dehydration level. PMID:8294266

Carey, M B; Zelick, R

1993-11-01

34

The location by early auditory evoked potentials (EAEP) of acoustic nerve and brainstem demyelination in multiple sclerosis (MS)  

Microsoft Academic Search

Tone pips of suprathreshold intensities elicit an acoustic nerve response (I) and six low amplitude brainstem potentials (II–VII) during the initial 10 ms. Seven waves were studied in 40 control subjects and 5 waves (I–V) in 47 patients with MS. The results suggest involvement of the auditory pathway of 24 of 27 patients in the clinically “definite”, of 5 of

K. Maurer; E. Schäfer; H. C. Hopf; H. Leitner

1980-01-01

35

An expert system for the analysis and interpretation of evoked potentials based on fuzzy classification: application to brainstem auditory evoked potentials.  

PubMed

EPEXS is an expert system for evoked potential analysis and interpretation (a medical examination performed in clinical neurophysiology laboratories), working from available clinical records and numerical data extracted from evoked potential traces. EPEXS integrates two formalisms of knowledge representation: rules and structured objects. The rules represent the elementary concepts (shallow knowledge) and include a model of possibility based on the Dubois and Prade default reasoning and possibility theory. The structured objects (prototypes) are organized as hierarchical taxonomies (underlying knowledge). These allow the description of both the objects and their relationships. The heuristics used to interpret knowledge are based on two hypotheses: the unicity of the pathological process leading to several given symptoms and the progression from the general to the specific, leading to the adoption or rejection of a class of diagnoses. This avoids the problem of the differential diagnosis. These sources of knowledge are used in a dynamical way that could be described as a four-step process: acquisition of clinical data in order to define the nosological frame of the pathology, production of hypotheses about the nature and topography of lesions, interpretation of data in accordance with these hypotheses, and finally evaluation of their likelihood. The validation shows that EPEXS topographic diagnoses were correct in 100% of cases and 92% of it nosologic diagnoses were correct, and no pathological record was interpreted as normal. When examined on a given pathology basis EPEXS was not significantly different from human experts as regards to performance, specificity, and sensitivity. PMID:7813199

Brai, A; Vibert, J F; Koutlidis, R

1994-10-01

36

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

PubMed Central

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.

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

37

A model for simulation of electrically evoked auditory brainstem responses  

NASA Astrophysics Data System (ADS)

An important aspect of research in the continued development of cochlear implants is the in vivo assessment of signal processing algorithms. One technique that has been used is evoked potentials, the recording of neural responses to auditory stimulation. Depending on the latency of the observed response, the evoked potential indicates neural activity at the various neurological structures of the auditory system. Electrically evoked ABRs are commonly measured in hearing-impaired patients who have cochlear implants, via electrical stimulation delivered by electrodes in the implanted array. This research explores the use of MATLAB for the purpose of developing a model for electrically evoked auditory brainstem responses (ABRs). The simulation model developed in this study takes as its input the stimulus current intensity level, and uses function vectors and equations derived from measured ABRs, to generate an approximation of the evoked surface potentials. A function vector is used to represent the combined firing of the neurons of the auditory nervous system that are needed to elicit a measurable response. Equations have been derived to represent the latency and stimulus amplitude scaling functions. The simulation also accounts for other neural activity that can be present in and contaminate an ABR recording, and reduces it through time-locked averaging of the simulated response. In the MATLAB simulation, the model performs well and delivers results that compare favorably with the results measured from the research subjects.

Miller, Douglas A.; Matin, Mohammed A.

2009-08-01

38

Inhalational Exposure to Carbonyl Sulfide Produces Altered Brainstem Auditory and Somatosensory-Evoked Potentials in Fischer 344N Rats  

Microsoft Academic Search

Carbonyl sulfide (COS), a chemical listed by the original Clean Air Act, was tested for neurotoxicity by a National Institute of Environmental Health Sciences\\/National Toxicology Program and U.S. Environmental Protection Agency collaborative investiga- tion. Previous studies demonstrated that COS produced cortical and brainstem lesions and altered auditory neurophysiological responses to click stimuli. This paper reports the results of ex- panded

David W. Herr; Jaimie E. Graff; Virginia C. Moser; Kevin M. Crofton; Peter B. Little; Daniel L. Morgan; Robert C. Sills

2007-01-01

39

Evoked potentials and contingent negative variation during treatment of multiple sclerosis with spinal cord stimulation  

Microsoft Academic Search

Cervical somatosensory evoked potentials, brainstem evoked potentials, visual evoked potentials, and the cerebral contingent negative variation were recorded in patients with definite multiple sclerosis before, during, and after spinal cord stimulation. Improvements were seen in the cervical somatosensory and brainstem evoked potentials but neither the visual evoked potential nor the contingent negative variation changed in association with spinal cord stimulation.

E M Sedgwick; L S Illis; R C Tallis; A R Thornton; P Abraham; E El-Negamy; T B Docherty; J S Soar; S C Spencer; F M Taylor

1980-01-01

40

Sensory evoked potentials in neurotoxicology.  

PubMed

This paper provides a summary of routine evoked potential tests used with rats, with elaboration on the cochlear microphonic portion of the auditory brainstem response, the effects of chemicals on high frequency (above 40 Hz) components of the somatosensory evoked potential, on cerebellar recording of sensory evoked potentials, and on central conduction time. An alternative to peak-valley amplitude and latency measurements is discussed, wherein a computer analyzes evoked potentials for differences from control in waveform shape, latency, and power. Since multiple use of statistics is common, resulting in an inflated false positive rate, an alpha criterion of less than 0.05 is recommended. Instead of dividing alpha by the number of statistical tests (Bonferroni), a less severe correction of dividing alpha by the square root of the number of tests is proposed. PMID:3073306

Mattsson, J L; Albee, R R

41

Gap prepulse inhibition and auditory brainstem-evoked potentials as objective measures for tinnitus in guinea pigs.  

PubMed

Tinnitus or ringing of the ears is a subjective phantom sensation necessitating behavioral models that objectively demonstrate the existence and quality of the tinnitus sensation. The gap detection test uses the acoustic startle response elicited by loud noise pulses and its gating or suppression by preceding sub-startling prepulses. Gaps in noise bands serve as prepulses, assuming that ongoing tinnitus masks the gap and results in impaired gap detection. This test has shown its reliability in rats, mice, and gerbils. No data exists for the guinea pig so far, although gap detection is similar across mammals and the acoustic startle response is a well-established tool in guinea pig studies of psychiatric disorders and in pharmacological studies. Here we investigated the startle behavior and prepulse inhibition (PPI) of the guinea pig and showed that guinea pigs have a reliable startle response that can be suppressed by 15 ms gaps embedded in narrow noise bands preceding the startle noise pulse. After recovery of auditory brainstem response (ABR) thresholds from a unilateral noise over-exposure centered at 7 kHz, guinea pigs showed diminished gap-induced reduction of the startle response in frequency bands between 8 and 18 kHz. This suggests the development of tinnitus in frequency regions that showed a temporary threshold shift (TTS) after noise over-exposure. Changes in discharge rate and synchrony, two neuronal correlates of tinnitus, should be reflected in altered ABR waveforms, which would be useful to objectively detect tinnitus and its localization to auditory brainstem structures. Therefore, we analyzed latencies and amplitudes of the first five ABR waves at suprathreshold sound intensities and correlated ABR abnormalities with the results of the behavioral tinnitus testing. Early ABR wave amplitudes up to N3 were increased for animals with tinnitus possibly stemming from hyperactivity and hypersynchrony underlying the tinnitus percept. Animals that did not develop tinnitus after noise exposure showed the opposite effect, a decrease in wave amplitudes for the later waves P4-P5. Changes in latencies were only observed in tinnitus animals, which showed increased latencies. Thus, tinnitus-induced changes in the discharge activity of the auditory nerve and central auditory nuclei are represented in the ABR. PMID:22666193

Dehmel, Susanne; Eisinger, Daniel; Shore, Susan E

2012-05-31

42

Gap prepulse inhibition and auditory brainstem-evoked potentials as objective measures for tinnitus in guinea pigs  

PubMed Central

Tinnitus or ringing of the ears is a subjective phantom sensation necessitating behavioral models that objectively demonstrate the existence and quality of the tinnitus sensation. The gap detection test uses the acoustic startle response elicited by loud noise pulses and its gating or suppression by preceding sub-startling prepulses. Gaps in noise bands serve as prepulses, assuming that ongoing tinnitus masks the gap and results in impaired gap detection. This test has shown its reliability in rats, mice, and gerbils. No data exists for the guinea pig so far, although gap detection is similar across mammals and the acoustic startle response is a well-established tool in guinea pig studies of psychiatric disorders and in pharmacological studies. Here we investigated the startle behavior and prepulse inhibition (PPI) of the guinea pig and showed that guinea pigs have a reliable startle response that can be suppressed by 15 ms gaps embedded in narrow noise bands preceding the startle noise pulse. After recovery of auditory brainstem response (ABR) thresholds from a unilateral noise over-exposure centered at 7 kHz, guinea pigs showed diminished gap-induced reduction of the startle response in frequency bands between 8 and 18 kHz. This suggests the development of tinnitus in frequency regions that showed a temporary threshold shift (TTS) after noise over-exposure. Changes in discharge rate and synchrony, two neuronal correlates of tinnitus, should be reflected in altered ABR waveforms, which would be useful to objectively detect tinnitus and its localization to auditory brainstem structures. Therefore, we analyzed latencies and amplitudes of the first five ABR waves at suprathreshold sound intensities and correlated ABR abnormalities with the results of the behavioral tinnitus testing. Early ABR wave amplitudes up to N3 were increased for animals with tinnitus possibly stemming from hyperactivity and hypersynchrony underlying the tinnitus percept. Animals that did not develop tinnitus after noise exposure showed the opposite effect, a decrease in wave amplitudes for the later waves P4–P5. Changes in latencies were only observed in tinnitus animals, which showed increased latencies. Thus, tinnitus-induced changes in the discharge activity of the auditory nerve and central auditory nuclei are represented in the ABR.

Dehmel, Susanne; Eisinger, Daniel; Shore, Susan E.

2012-01-01

43

Auditory Brainstem Evoked Responses in Newborns with Down Syndrome  

ERIC Educational Resources Information Center

|Auditory brainstem evoked responses (ABRs) were compared in 15 newborns with Down syndrome and 15 sex-, age-, and weight-matched control newborns. Participants had normal ABRs based upon values specific to 32- to 42-weeks postconceptional age. Although Wave III and Wave V component latencies and the Wave I-III interpeak latency (IPL) were shorter…

Kittler, Phyllis M.; Phan, Ha T. T.; Gardner, Judith M.; Miroshnichenko, Inna; Gordon, Anne; Karmel, Bernard Z.

2009-01-01

44

Auditory Brainstem Evoked Responses in Newborns with Down Syndrome  

ERIC Educational Resources Information Center

Auditory brainstem evoked responses (ABRs) were compared in 15 newborns with Down syndrome and 15 sex-, age-, and weight-matched control newborns. Participants had normal ABRs based upon values specific to 32- to 42-weeks postconceptional age. Although Wave III and Wave V component latencies and the Wave I-III interpeak latency (IPL) were shorter…

Kittler, Phyllis M.; Phan, Ha T. T.; Gardner, Judith M.; Miroshnichenko, Inna; Gordon, Anne; Karmel, Bernard Z.

2009-01-01

45

Brainstem Auditory Evoked Response in Children with Central Language Disturbance.  

ERIC Educational Resources Information Center

|Two groups of 10 children between the ages of 94 and 165 months were paired for age (wthin 6 months) and sex and were compared for Brainstem Auditory Evoked Response patterns. One child in each pair showed evidence of central language disturbance as determined by neuropsychological testing. The other did not. All had normal hearing and IQs of 80…

Piggott, Leonard R.; Anderson, Theodora

1983-01-01

46

Speech-evoked brainstem responses in Arabic and Hebrew speakers.  

PubMed

Based on studies in English speakers, it has been proposed that speech-evoked brainstem responses (ABRs) may be used clinically to assess central auditory function. Whether the same procedure can be used across speakers of different languages remains unclear, because recent findings suggest that language experience affects even subcortical processing of speech. The goal of the present study was to characterize brainstem responses to the syllable /da/ in Arabic and Hebrew speakers using the US developed BioMARK procedure. To that end, ABRs evoked by clicks and the syllable /da/ were collected from 37 normal-hearing students from the University of Haifa. Neither the transient nor the sustained components of the brainstem response differed significantly between Arabic and Hebrew speakers. Across the two groups, timing of the major components of the speech-evoked response as well as the correlations between the speech- and click indices were well within the US norms. Therefore, brainstem processing of the syllable /da/ does not differ between speakers of English and speakers of Semitic languages such as Arabic and Hebrew. PMID:20666694

Karawani, Hanin; Banai, Karen

2010-11-01

47

Kcna1 gene deletion lowers the behavioral sensitivity of mice to small changes in sound location and increases asynchronous brainstem auditory evoked potentials but does not affect hearing thresholds.  

PubMed

Sound localization along the azimuth depends on the sensitivity of binaural nuclei in the auditory brainstem to small differences in interaural level and timing occurring within a submillisecond epoch and on monaural pathways that transmit level and timing cues with high temporal fidelity to insure their coincident arrival at the binaural targets. The soma and axons of these brainstem neurons are heavily invested with ion channels containing the low-threshold potassium channel subunit Kv1.1, which previous in vitro and in vivo studies suggest are important for regulating their high input-output correspondence and temporal synchrony. We compared awake Kcna1-null mutant (Kcna1-/-) mice lacking Kv1.1 with Kcna1+/+ mice to determine whether Kv1.1 activity contributes to sound localization and examined anesthetized mice for absolute hearing thresholds for suprathreshold differences that may be revealed in the waveforms of auditory brainstem response potentials. The awake -/- mice tested with reflex modification audiometry had reduced sensitivity to an abrupt change in the location of a broad band noise compared to +/+ mice, while anesthetized -/- mice had normal absolute thresholds for tone pips but a high level of stimulus-evoked but asynchronous background activity. Evoked potential waveforms had progressively earlier peaks and troughs in -/- mice, but the amplitude excursions between adjacent features were identical in the two groups. Their greater excitability and asynchrony in suprathreshold evoked potentials coupled with their normal thresholds suggests that a disruption in central neural processing in -/- mice and not peripheral hearing loss is responsible for their poor sound localization. PMID:22396426

Allen, Paul D; Ison, James R

2012-02-15

48

Kcna1 gene deletion lowers the behavioral sensitivity of mice to small changes in sound location and increases asynchronous brainstem auditory evoked potentials, but does not affect hearing thresholds  

PubMed Central

Sound localization along the azimuth depends on the sensitivity of binaural nuclei in the auditory brainstem to small differences in interaural level and timing occurring within a sub-millisecond epoch, and on monaural pathways that transmit level and timing cues with high temporal fidelity to insure their coincident arrival at the binaural targets. The soma and axons of these brainstem neurons are heavily invested with ion channels containing the low-threshold potassium channel subunit Kv1.1, which previous in-vitro and in-vivo studies suggest are important for regulating their high input-output correspondence and temporal synchrony. We compared awake Kcna1 null mutant (?/?) mice lacking Kv1.1 with +/+ mice to determine if Kv1.1 activity contributes to sound localization, and examined anesthetized mice for absolute hearing thresholds for suprathreshold differences that may be revealed in the waveforms of auditory brainstem response potentials. The awake ?/? mice tested with reflex modification audiometry had reduced sensitivity to an abrupt change in the location of a broad band noise compared to +/+ mice, while anesthetized ?/? mice had normal absolute thresholds for tone pips but a high level of stimulus-evoked but asynchronous background activity. Evoked potential waveforms had progressively earlier peaks and troughs in ?/? mice but the amplitude excursions between adjacent features were identical in the two groups. Their greater excitability and asynchrony in suprathreshold evoked potentials coupled with their normal thresholds suggests that a disruption in central neural processing in ?/? mice and not peripheral hearing loss is responsible for their poor sound localization.

Allen, Paul D.; Ison, James R.

2012-01-01

49

Evoked Potentials in the Evaluation of Patients with Mitochondrial Myopathy  

Microsoft Academic Search

Multimodality evoked potentials and pattern electroretinograms (PERGs) were performed in seventeen patients with histologically defined mitochondrial myopathy (MM). Brainstem auditory evoked potentials showed abnormalities in 47% and somatosensory evoked potentials in 76%. Visual evoked potentials were outside the normal range in 71%; PERGs exhibited a decreased amplitude or delayed P50 in 78%. These findings may be considered as an expression

Ferdinando Sartucci; Bruno Rossi; Gloria Tognoni; Gabriele Siciliano; Valentina Guerrini; Luigi Murri

1993-01-01

50

Brainstem Maturation after Antenatal Steroids Exposure in Premature Infants as Evaluated by Auditory Brainstem-Evoked Response  

Microsoft Academic Search

OBJECTIVE: Antenatal steroids result in fetal lung maturation, but may retard brain development. Auditory brainstem-evoked response (ABR) is a noninvasive assessment of brainstem maturation. The objective of this study was to determine if antenatal steroids affect brainstem maturation in infants ?32 weeks gestational age (GA).DESIGN\\/METHODS: Bilateral monaural ABR were performed within the first 24 hours using 80 db nHL unfiltered

Sanjiv B Amin; Mark S Orlando; Larry E Dalzell; Kathleen S Merle; Ronnie Guillet

2003-01-01

51

Cumulative Lifelong Alcohol Consumption Alters Auditory Brainstem Potentials  

Microsoft Academic Search

Background: Alcohol is one of the most widely abused substances in the United States and Europe. It is believed that alcohol causes brain damage that may influence the central auditory tracts. Brainstem auditory evoked potentials (BAEPs) are a common method for measuring central auditory pathways. Therefore, the influence of cumulative lifelong alcohol consumption on BAEPs in subjects with normal hearing

Elisabeth Stephanie Smith; Herbert Riechelmann

2004-01-01

52

Ocular vestibular evoked myogenic potentials are abnormal in internuclear ophthalmoplegia  

Microsoft Academic Search

ObjectiveThe cervical vestibular evoked myogenic potential (cVEMP) is sensitive to lower brainstem lesions affecting the vestibulo-collic pathway. We wished to determine whether the ocular VEMP (oVEMP), a recently-described otolith–ocular reflex, is also abnormal in patients with brainstem lesions. We tested patients with internuclear ophthalmoplegia (INO), caused by a brainstem lesion in the medial longitudinal fasciculus (MLF), to investigate whether the

S. M. Rosengren; J. G. Colebatch

2011-01-01

53

[Spasmodic torticollis, substantiating Manto syndrome, of possible toxic aethiology, with alterations of brainstem acoustic evoked potentials (BAEPs). Treatment with L-5-hydroxytryptophan. Follow up of 18 months, during which high degree resolution of symptoms and normalization of BAEPs took place].  

PubMed

A case of very severe spasmodic torticollis observed for 18 months is presented and discussed. Head was so rotated that permitted only backward seeing and compressed brachial plexus between scaleni muscles with sensory, motor and trophic troubles in the hand. A toxic aethiology from parathion is likely. Brainstem Acoustic Evoked Potentials (BAEPs) showed in the beginning abnormal responses, especially as refers to waves originating in the mesencephalon. Therapy with L-5-hydroxytryptophan subdued neurological symptoms; a parallel normalization of BAEPs recording was observed. The Authors propose to call this syndrome (spasmodic torticollis with thoracic outlet syndrome) after the mythical diviner Manto, which Dante Alighieri refers to in his "Divina Commedia" (Inferno, XX, 55 e segg.). PMID:6985243

Disertori, B; Ducati, A; Piazza, M

54

Visual evoked potentials in neonatal hyperbilirubinemia.  

PubMed

The management of neonatal hyperbilirubinemia is very standardized. However, there is a lack of an objective method to evaluate the cerebral effects of bilirubin apart from brainstem auditory evoked potentials. There were few studies evaluating the effects of hyperbilirubinemia or phototherapy on the visual pathway in infants with hyperbilirubinemia. Serial visual evoked potentials of two groups of term neonates (N = 24)--group 1 with moderate hyperbilirubinemia (n = 16) and group 2 with severe hyperbilirubinemia (n = 8)--were evaluated prospectively. All infants had regular physical, neurologic, visual, and auditory evaluations until 3 years. Four (16%) had abnormal visual evoked potentials before 1 year, and the abnormalities returned to normal thereafter. There was no significant difference in visual evoked potentials between the two groups. All had normal neurodevelopmental status by 3 years, with the exception of one child from the severe group with ABO incompatibility with transient mild motor delay, hypotonia, and abnormal visual evoked potential. There were no abnormal effects of phototherapy on visual evoked potentials in infants with neonatal hyperbilirubinemia after 1 year of age. Although our sample size was small, the results suggest that the effects of hyperbilirubinemia on visual evoked potentials might be transient. (J Child Neurol 2006;21:58-62). PMID:16551455

Chen, Wen-Xiong; Wong, Virginia

2006-01-01

55

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...

56

Differential Impact of Hypothermia and Pentobarbital on Brain-Stem Auditory Evoked Responses.  

National Technical Information Service (NTIS)

Two experiments were conducted to determine the effects of hypothermia and pentobarbital anesthesia, alone and in combination, on the brain-stem auditory evoked responses (BAERs) of rats. In experiment I, unanesthetized rats were cooled to colonic tempera...

R. Janssen B. E. Hetzler J. P. Creason R. S. Dyer

1991-01-01

57

Evoked Potential Variability  

PubMed Central

An unsupervised correlation-based clustering method was developed to assess the trial-to-trial variability of auditory evoked potentials (AEPs). The method first decomposes single trials into three frequency bands, each containing activity primarily associated with one of the three major AEP components, i.e., P50, N100 and P200. Next, single-trial evoked potentials with similar post-stimulus characteristics are clustered and selectively averaged to determine the presence or absence of an AEP component. The method was evaluated on actual AEP and spontaneous EEG data collected from 25 healthy participants using a paradigm in which pairs of identical tones were presented, with the first stimulus (S1) presented 0.5 s before the second stimulus (S2). Homogeneous, well-separated clusters were obtained and substantial AEP variability was found. Also, there was a trend for S2 to produce fewer ‘complete’ (and significantly smaller) responses than S1. Tests conducted on spontaneous EEG produced similar clusters as obtained from EP data, but significantly fewer stimuli produced responses containing all three EP components than seen in AEP data. These findings suggest that the clustering method presented here performs adequately to assess trial-to-trial EP variability. Also, the results suggest that the sensory gating observed in normal controls may be caused by the fact that the second stimulus generates fewer ‘responsive’ trials than the first stimulus, thus resulting in smaller ensemble averages.

Hu, Lingli; Boutros, Nash N.; Jansen, Ben H.

2008-01-01

58

UNRECOGNIZED ERRORS DUE TO ANALOG FILTERING OF THE BRAIN-STEM AUDITORY EVOKED RESPONSE  

EPA Science Inventory

The brainstem auditory evoked response (BAER) is used as a tool both in clinical evaluation and in toxicological research, where the subject is most often the laboratory rat. As in other species, interpretation of the rat BAER waveform is based on the latencies and amplitudes of ...

59

DIFFERENTIAL IMPACT OF HYPOTHERMIA AND PENTOBARBITAL ON BRAINSTEM AUDITORY EVOKED RESPONSE  

EPA Science Inventory

Two experiments were conducted to determine the effects of hypothermia and pentobarbital anesthesia, alone and in combination, on the brainstem auditory evoked responses (BAERs) of rats. n experiment I, unanesthetized rats were cooled to colonic temperatures 0.5 and 1.0 degrees C...

60

[The importance of brain stem evoked potentials in the diagnosis of neurosurgical patients].  

PubMed

The technique of Brainstem Electric Response Audiometry (BERA) is a non-invasive electrophysiologic method used in comatose patients for localization of areas of neuronal and synaptic dysfunction not evident in clinical evaluation. This test has a diagnostic and prognostic value in detection of abnormalities and evaluation of comatose head-injured patients at a reversible clinical stage. In contrast to most clinical signs, brainstem auditory evoked potentials are independent of levels of consciousness, analgesics, sedatives. This test is aetiologically non-specific and must be carefully integrated into the clinical situation. Generators of brainstem auditory evoked potentials are located in the auditory nerve (waves I and II) and brainstem (waves III-V). Patients in acute posttraumatic coma are assessed by means of Glasgow Coma Score (GCS), which is reliable in forecasting a favourable outcome. Patients with a score 8 points have an unfavourable outcome in 16%. Brainstem auditory evoked potentials are reliable predictors of unfavourable outcome. Subsequent brainstem auditory evoked potential testing provides relevant prognostic information, since improvement of graded brainstem auditory evoked potentials indicates a favourable outcome. Progressive deterioration of brainstem auditory evoked potentials indicates irreversible damage and is associated with unfavourable outcome, whereas singular abnormal evoked potentials may result from reversible neuronal dysfunction. The absence of waves III-V associated with the end EEG activity is the proof of brain death. Serial BERA monitoring has been used to evaluate progressive clinical syndromes, such as "uncal herniation" and evolving brain death. The use of serial BERA recordings appeared to improve the outcome predictions in comparison with single BERA tests. A combination of brainstem auditory evoked potentials, somatosensory and visual evoked potentials (multimodality evoked potentials-MEP) provides more information for management of a patient than a single evoked potential modality. The main goal to use BERA is early detection of secondary deterioration in comatose patients suffering from intracranial lesions. The results of brainstem auditory evoked potentials and clinical examination of patients obtained within the acute phase after head injury may indicate increased intracranial pressure (ICP) and incipient transtentorial herniation but do not always predict outcome (GOS). The outcome can be better evaluated later, 3-6 days after head injury. In summary, BERA is a non-invasive, safe and objective method of evaluating patients after severe head injury and adds valuable information for assessment of their outcome. PMID:11783409

Rogowski, M; Michalska, B I

61

Test-retest consistency of speech-evoked auditory brainstem responses in typically-developing children  

PubMed Central

The click-evoked auditory brainstem response (ABR) is widely used in clinical settings, partly due to its predictability and high test-retest consistency. More recently, the speech-evoked ABR has been used to evaluate subcortical processing of complex signals, allowing for the objective assessment of biological processes underlying auditory function and auditory processing deficits not revealed by responses to clicks. Test-retest reliability of some components of speech-evoked ABRs has been shown for adults and children over the course of months. However, a systematic study of the consistency of the speech-evoked brainstem response in school-age children has not been conducted. In the present study, speech-evoked ABRs were collected from 26 typically-developing children (ages 8-13) at two time points separated by one year. ABRs were collected for /da/ presented in quiet and in a 6-talker babble background noise. Test-retest consistency of response timing, spectral encoding, and signal-to-noise ratio was assessed. Response timing and spectral encoding were highly replicable over the course of one year. The consistency of response timing and spectral encoding found for the speech-evoked ABRs of typically-developing children suggests that the speech-evoked ABR may be a unique tool for research and clinical assessment of auditory function, particularly with respect to auditory-based communication skills.

Hornickel, Jane; Knowles, Erica; Kraus, Nina

2012-01-01

62

Prognostic value of evoked potentials and sleep recordings in the prolonged comatose state of children. Preliminary data  

Microsoft Academic Search

Objectives – Sleep recordings and evoked potentials (EPs) were used in five comatose children to evaluate their predictive value for outcome following a severe comatose state. Methods and subjects – The protocol included EEG, Brainstem Evoked Responses (BERs), Somatosensory Evoked Potentials (SEPs) and polysomnography. From 10 to 15 days post-coma (D10 to D15), EEG and clinical examinations were carried out every second

F. Chéliout-Heraut; R. Rubinsztajn; C. Ioos; B. Estournet

2001-01-01

63

Potenciais evocados auditivos em indivíduos acima de 50 anos de idade***** Auditory evoked potentials in individuals over 50 years  

Microsoft Academic Search

Background: auditory evoked potentials. Aim: to describe the results of brainstem auditory evoked potentials (PEATE), middle latency auditory evoked potentials (PEAML) and cognitive potential (P300) in individuals over 50 years. Method: this study was developed at the Speech and Hearing Investigation Laboratory in Auditory Evoked Potentials of the Speech-Language and Hearing Course of the Department of Physiotherapy, Speech-language and Hearing

Carla Gentile Matas; Valdete Alves; Valentins dos Santos Filha; Melissa Mitsue Cunha; Pires Okada; Juliana Reis Resque

64

Multimodal evoked potentials after subarachnoid haemorrhage.  

PubMed

In 59 comatose patients after subarachnoid haemorrhage somatosensory, visual, auditory and magnetic motor evoked potentials were registered. Evoked potentials proved to be of much less predictive value than in other causes of coma, such as head injury and others. While loss of cortical function was a safe predictor of a fatal outcome, preservation of evoked potentials has little prognostic relevance. PMID:7913522

Firsching, R

1994-02-01

65

[Effect of anesthetics on sensory evoked potentials].  

PubMed

The authors have reviewed the main effects of anaesthetic agents on sensory evoked potentials (EPs) in the auditory, somatosensory and visual modalities. Knowledge of EP changes induced by anesthetic drugs is important to avoid false alarms when monitoring neural structures at risk during surgery. Intraoperative EP monitoring is all the more efficient as the following points are taken into account: 1) whatever the sensory modality considered, EPs are more attenuated by volatile halogenated agents than by intravenous drugs; 2) the cortical components of EPs are more sensitive to anesthetic drugs than the brainstem components; 3) in each modality, the first component of the "primary cortical complex" is less attenuated by anaesthetic agents than the following cortical waves; 4) continuous administration of anaesthetic agents rather than acute administration (bolus) is preferred during EP monitoring. EPs also represent an objective means to assess the depth of surgical anaesthesia, since they may provide a reliable index of cortical depression. Amplitude changes of middle-latency auditory responses (Pa/Nb) seem to be a good marker for estimating depth of anaesthesia with the aid of EPs. PMID:8326927

García-Larrea, L; Fischer, C; Artru, F

1993-05-01

66

Vestibular Evoked Myogenic Potentials in Patients With Acoustic Neuromas  

Microsoft Academic Search

Background: To diagnose acoustic neuromas (ANs), the auditory brainstem response test and the caloric test have been used in addition to magnetic resonance imaging. The auditory brainstem response and the caloric tests mainly reflect functions of the auditory pathway, ie, the cochlear nerve and the superior vestibular nerve, respec- tively. Because the vestibular evoked myogenic poten- tial (VEMP) has been

Toshihisa Murofushi; Masaki Matsuzaki; Masahiro Mizuno

1998-01-01

67

RECORDING OF VESTIBULAR EVOKED MYOGENIC POTENTIALS  

Microsoft Academic Search

It has been shown recently that loud clicks evoke myogenic potentials in the tonically contracting sternocleidomastoid muscles. Studies have suggested that these potentials are of vestibular origin, especially of the saccule and inferior vestibular nerve. A pilot study was undertaken in our hospital to record vestibular evoked myogenic potentials (VEMP) for the first time in Iran. Eighteen healthy volunteers (32

A. A. Sazgar; K. Akrami; S. Akrami; A. R. Karimi Yazdi

68

Effect of thyroxine on the development of somatosensory and visual evoked potentials in the rat  

Microsoft Academic Search

The thyroid hormone thyroxine (T4), administered post-natally to neonatal rats, has been shown to accelerate development of auditory function, as expressed by auditory nerve-brainstem evoked responses. This study investigated whether this earlier development was also reflected in other sensory modalities. Rat pups were injected with T4 from the day of birth for 10 consecutive days. Somatosensory evoked potentials, both from

Sharon Freeman; Haim Sohmer

1995-01-01

69

USE OF SENSORY EVOKED POTENTIALS IN TOXICOLOGY  

EPA Science Inventory

The rationale for studying sensory systems as an integral part of neurotoxicological examinations is presented. The role of evoked potentials in assessing brain dysfunction in general and sensory systems in particular is also presented. Four types of sensory evoked potentials (br...

70

Evoked-Potential Correlates of Stimulus Uncertainty  

Microsoft Academic Search

The average evoked-potential waveforms to sound and light stimuli recorded from scalp in awake human subjects show differences as a function of the subject's degree of uncertainty with respect to the sensory modality of the stimulus to be presented. Differences are also found in the evoked potential as a function of whether or not the sensory modality of the stimulus

Samuel Sutton; Margery Braren; Joseph Zubin; E. R. John

1965-01-01

71

Abnormal brain stem auditory evoked potentials in a girl with the central alveolar hypoventilation syndrome.  

PubMed

Brainstem auditory evoked potentials were recorded in a 3-year-old girl with the central alveolar hypoventilation syndrome (Ondine's syndrome). Abnormal findings were seen at the level of the mid to upper brain stem (wave III), which was not reproducibly recordable on the left side. This electrophysiologic abnormality is consistent with a previous finding in a patient with sleep apnea. PMID:9003972

Litscher, G; Schwarz, G; Reimann, R

1996-11-01

72

[Somatosensory evoked potentials/fields--exploration of brain function].  

PubMed

We have summarized the history of electroencephalography(EEG) since 1875, when a paper by Richard Caton was published describing the first EEG recordings in animals. Somatosensory evoked potentials (SEPs) were recorded by George Dawson in 1951. Thereafter, SEPs were developed for clinical use with other evoked potentials such as auditory evoked potentials(VEPs). To understand evoked potentials, related mechanism of induction of far-fields-potentials(FFP) following stimulation of the median nerve has been discussed. SEPs consisted of P9, N9, N10, P11, N11, N13, P13, P14, N18, N20 and P20/P22. Scalp recorded P9 FFP arises from the distal portion of the branchial plexus as reflected by N9 stationary negative potential recorded over the stimulated arm. Cervical N11 and N13 arise from the root entry zone and dorsal horn, respectively. Scalp recorded P13, P14 and N18 FFP originate from the brainstem. In this communication, magnetoencephalography(MEG) and results of one of our recent studies on somatosensory evoked fields(SEFs) are also discussed. One of the important features of MEG is that magnetic signals detected outside the head arise mainly from cortical currents tangential to the skull. Since the net postsynaptic current follows the orientation of cortical pyramidal cells, the MEG signals mainly reflect activity of the fissural cortex, whereas radial current may remain undetected. In our study, we demonstrated SEFs elicited by compression and decompression of a subject's glabrous skin by a human operator. Their dipoles were tangentially oriented from the frontal lobe to parietal lobe. PMID:14968564

Inoue, Ken; Shirai, Takushi; Harada, Toshihide; Mimori, Yasuyo; Matsumoto, Masayasu

2004-01-01

73

Ultra Fast Quantification of Hearing Loss by Neural Synchronization Stabilities of Auditory Evoked Brainstem Activity  

Microsoft Academic Search

Recently, we proposed a new novelty detection paradigm for the fast detection of hearing thresholds using single sweeps of auditory evoked potentials as efficient approach to newborn hearing screening. Such a method might prevent currently used time consuming averaging procedures which require the state of spontaneous sleep, sedation, or narcosis of the newborns when using such systems in universal newborn

F. I. Corona-Strauss; W. Delb; M. Bloching; D. J. Strauss

2007-01-01

74

[Evoked somatosensory plexus and cervical evoked potentials in cervicobrachialgia].  

PubMed

The authors study the sensitive potential evoked from point of Erb and from cervical spine in C6-C7, obtained by stimulation of median nerve in a control group (normals) and in a greater group of 40 cases from patients affected by radiculopathie with or without discal protrusion and by myelopathie spondiloartrosic. The date supply significant informations and are (obicurred in analytique) analyzed with accuracy. PMID:6879059

Rossi, L; Ubiali, E; Merli, R; Rottoli, M R

75

Inhibitory effect of capsaicin evoked trigeminal pain on warmth sensation and warmth evoked potentials.  

PubMed

The aim of the study was to evaluate the effect of tonic pain evoked by topical application of capsaicin on the somatosensory sensation of warmth. The warmth pathways were studied in ten healthy subjects by recording the scalp potentials evoked by non-painful warm laser stimuli delivered on both the right and left perioral region (warmth C-fiber related laser-evoked potentials (C-LEPs)). Tonic pain was induced by topical capsaicin application above the lateral part of the right upper lip. The area of primary and secondary hyperalgesia were mapped. C-LEPs were obtained from 31 scalp electrodes before, during, and after capsaicin application. C-LEPs from the right perioral region were evoked by laser stimuli delivered to the area of secondary hyperalgesia during capsaicin application and on both the areas of primary and secondary hyperalgesia after capsaicin removal. While the lateralized N1/P1 component (around 185 ms of latency) was not affected by the capsaicin, the amplitudes of the later vertex C-LEPs (around 260 and 410 ms of latency for the N2a and P2 potentials, respectively) evoked from the secondary hyperalgesic area on the right side and from a symmetrical non-hyperalgesic area on the left perioral region were significantly decreased during capsaicin application and after capsaicin removal, as compared with the baseline recordings. At the same times, the rating of the laser-evoked warmth sensation was reduced significantly. This inhibitory effect can occur at brainstem level and is possibly due to: 1) trigemino-cortico-trigeminal circuits, similar to those mediating the classical diffuse noxious inhibitory control, or 2) an increased background activity of the capsaicin-insensitive A-fibers, which mediate the secondary hyperalgesia. Probably due to a peripheral inhibitory mechanism, neither reliable C-LEP components nor warmth sensation were evoked by laser pulses delivered to the primary hyperalgesic area. This is the first neurophysiological evidence in humans of an inhibitory effect of pain on warmth sensation. PMID:15316704

Valeriani, Massimiliano; Tinazzi, Michele; Le Pera, Domenica; Restuccia, Domenico; De Armas, Liala; Maiese, Toni; Tonali, Pietro; Arendt-Nielsen, Lars

2005-01-01

76

ONE YEAR OUTCOME OF BABIES WITH SEVERE NEONATAL HYPERBILIRUBINEMIA AND REVERSIBLE ABNORMALITY IN BRAINSTEM AUDITORY EVOKED RESPONSES  

Microsoft Academic Search

Brainstem auditory evoked responses (BAER) were longitudinally recorded prospec- tively in 18 term infants with neonatal hyperbil- irubinemia (NHB) (total serum bilirubin >15 mg\\/dl). Seven neonates had abnormal BAER. Wave complex IV-V was absent in eight record- ings in NHB group while they were normal in the control group (p <0.001). Prolongation of laten- cy of waves I and V

A. K. Deorari; Meharban Singh; G. K. Ahuja; M. S. Bisht; Ashok Verma; V. K. Paul; D. A. Tandon

77

[350m heliox saturated diving test--dynamic observation on hearing threshold, brainstem evoked response and acoustic impedance].  

PubMed

Four divers were investigated simulating a diving of 350m with saturated heliox under compression, performed in Jan 1989 at Navy Medical Institute. Changes in hearing threshold, brainstem evoked response and acoustic impedance were observed. The 4 divers experienced no tinnitus, hard of hearing and earache during compression and decompression. Objective examination showed loss of lower frequency range of hearing, that was due to the masking effect of the noise in the chamber. Changes in the wave--form and latency of brainstem evoked response were due to a change in sound wave transmission effected by the chamber pressure and a poor signal to noise ratio in the hyperbaric chamber of helium oxygen environment. All the changes were transient, after leaving the chamber, the hearing threshold and brainstem evoked response all returned to normal. Besides, there were no changes in the tympanogram, acoustic compliance and stapedius reflex before and after the experiment. Therefore the profile of compression and decompression in the experiment brought no harm to the divers' acoustic system; their Eustachian tubes, middle and inner ears functioned normally. PMID:1679643

Wang, L

1991-01-01

78

Saturation diving with heliox to 350 meters. Observation on hearing threshold, brainstem evoked response and acoustic impedance.  

PubMed

Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of hearing, earache during compression. Examination showed that the threshold of lower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient. After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test. PMID:7882734

Wang, L; Jiang, W; Gong, J H; Zheng, X Y

1994-12-01

79

Interhemispheric Asymmetries in Visual Evoked Potential Amplitude.  

National Technical Information Service (NTIS)

Interhemispheric differences in visual evoked potential amplitude (microvolts root mean square) were measured in five right-handed male subjects. Five different stimuli were used, and each subject participated in 3 similar test sessions. The stimuli inclu...

C. L. Schlichting D. F. Neri S. W. Kindness

1980-01-01

80

Multimodality evoked potentials in myotonic dystrophy  

Microsoft Academic Search

Multimodality evoked potentials were performed in 18 patients affected by myotonic dystrophy (8 males and 10 females); the aim was to make an electrophysiological evaluation of the central nervous system involvement in this disease.

F. Sartucci; F. Marconi; E. Busso; B. Rossi; L. Murri

1989-01-01

81

Fever and evoked potentials in multiple sclerosis  

Microsoft Academic Search

The somatosensory evoked potentials (SEPs) and visual evoked potentials (VEPs) were studied in 19 patients with multiple sclerosis; 17 controls were studied during fever (38.0°–39.7°C) and 2–3 days following return to normal temperature. The latencies of components N20 and P114 were measured and specified as abnormal when their value exceeded the standard deviation of the controls by 2.5 times. The

A. Kazis; N. Vlaikidis; D. Xafenias; J. Papanastasiou; P. Pappa

1982-01-01

82

Evoked potential application to study of echolocation in cetaceans  

NASA Astrophysics Data System (ADS)

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.

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

2002-05-01

83

Canine brainstem auditory evoked responses are not clinically impacted by head size or breed.  

PubMed

Accurate assessment of canine hearing is essential to decrease the incidence of hereditary deafness in predisposed breeds and to substantiate hearing acuity. The Brainstem Auditory Evoked Response (BAER) is a widely accepted, objective test used in humans and animals for estimation of hearing thresholds and deafness diagnosis. In contrast to humans, testing and recording parameters for determination of normal values for canine hearing are not available. Conflicting information concerning breed and head size effects on canine BAER tests are major contributors preventing this normalization. The present study utilized standard head measurement techniques coupled with BAER testing and recording parameters modeled from humans to examine the effect canine head size and breed have on BAER results. Forty-three adult dogs from fourteen different breeds had head size measurements and BAER tests performed. The mean latencies compared by breed for waves I, II, III, IV, and V were as follows: 1.46±0.49 ms, 2.52±0.54 ms, 3.45±0.41 ms, 4.53±0.83 ms and 5.53±0.43 ms, respectively. The mean wave I-V latency interval for all breeds was 3.69 ms. All dogs showed similar waveform morphology, structures, including the presence of five waves occurring within 11 ms after stimulus presentation and a significant trough occurring after Wave V. All of the waveform morphology for our subjects occurred with consistent interpeak latencies as shown by statistical testing. All animals had diagnostic results within the expected ranges for each wave latency and interwave interval allowing diagnostic evaluation. Our results establish that neither differences in head size nor breed impact determination of canine BAER waveform morphology, latency, or hearing sensitivity for diagnostic purposes. The differences in canine head size do not have a relevant impact on canine BAERs and are not clinically pertinent to management or diagnostic decisions. PMID:23262145

Kemper, Debra L; Scheifele, Peter M; Clark, John Greer

2012-12-21

84

Association of Hemoglobin levels and Brainstem Auditory Evoked Responses in Lead-Exposed Children  

PubMed Central

Objectives Decreased blood hemoglobin (HbB) levels and anemia have been associated with abnormal brainstem auditory evoked responses (BAER). Lead (Pb) exposure has also been associated with anemia and aberrant BAER. This study investigated the relationship between HbB level and BAER wave latency and amplitude in Pb-exposed Andean children. Design and methods Sixty-six children aged 2 to 15 years (mean age: 9.1; SD: 3.3) living in Pb-contaminated villages were screened for HbB levels, blood Pb (PbB) levels and BAER latencies and amplitudes. Results The mean HbB level observed in the study group was 11.9 g/dL (SD: 1.4; range: 8.6–14.8 g/dL). The mean HbB level corrected for altitude was 10.3 g/dL (SD: 1.4; range: 6.9–13.1 g/dL), and suggestive of anemia. The mean PbB level was 49.3 ?g/dL (SD: 30.1; range: 4.4–119.1 ?g/dL) and indicative of Pb poisoning. Spearman Rho correlation analyses revealed significant associations between the BAER absolute latencies and HbB level, indicating that as the HbB level decreased, the BAER wave latency increased. Children with low HbB levels (?11 g/dL) showed significantly prolonged absolute latencies of waves I, II, III, IV and V compared to the children with normal HbB levels. Although a significant relationship between HbB and BAER waves was observed, no significant associations between PbB level and BAER parameters were found. Conclusion Low hemoglobin levels may diminish auditory sensory-neural function, and is therefore an important variable to consider when assessing BAER in children with anemia and/or Pb exposure.

Counter, S. Allen; Buchanan, Leo H.; Ortega, Fernando

2012-01-01

85

Deconvolution of the vestibular evoked myogenic potential  

Microsoft Academic Search

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 a “mean” motor unit, and the temporal modulation of the MUAP rate of all contributing motor units, briefly called rate modulation. The latter is the function

Bernd Lütkenhöner; Türker Basel

86

Auditory evoked potentials in young patients with Down syndrome. Event-related potentials (P3) and histaminergic system  

Microsoft Academic Search

Subjects with Down syndrome exhibit various types of cognitive impairment. Besides abnormalities in a number of neurotransmitter systems (e.g. cholinergic), histaminergic deficits have recently been identified. Brainstem auditory evoked potentials (BAEPs) and auditory event-related potentials (ERPs), were recorded from 10 children (aged 11–20 years) with Down syndrome and from 10 age- and sex-matched healthy control subjects. In Down subjects, BAEPs

Rainer Seidl; Erwin Hauser; Günther Bernert; Manfred Marx; Michael Freilinger; Gert Lubec

1997-01-01

87

Somatosensory evoked potential monitoring during carotid surgery  

Microsoft Academic Search

Controversy exists over the value of intraoperative monitoring and shunting in patients undergoing carotid endarterectomy. Although it is widely believed that contralateral carotid occlusion and previous stroke mandate intraoperative shunting, the susceptibility of these two groups of patients to cerebral ischemia during carotid artery endarterectomy is not well defined. Somatosensory evoked potentials (SSEPs) were monitored in 113 carotid artery endarterectomy

M. L. Schwartz; T. F. Panetta; B. J. Kaplan; A. D. Legatt; W. D. Suggs; K. R. Wengerter; M. L. Marin; F. J. Veith

1996-01-01

88

Vestibular evoked myogenic potentials of undiagnosed dizziness  

Microsoft Academic Search

ObjectiveRecording of vestibular evoked myogenic potentials (VEMP) can facilitate the evaluation of otolith function. The dizziness caused by otolith lesions is not completely understood. To clarify which symptoms of dizziness originate from the otolith organs, we examined the relationship between symptoms and VEMP results in patients with undiagnosed dizziness.

Toru Seo; Atsushi Miyamoto; Michiko Node; Masafumi Sakagami

2008-01-01

89

Vestibular Evoked Myogenic Potentials in Preterm Infants  

Microsoft Academic Search

The goal of this study was to determine whether there was an association between perinatal risk factors of prematurity and vestibular evoked myogenic potentials (VEMPs). A prospective case-control trial was designed. Fifty preterm newborns (100 ears) with a gestational age <37 weeks were included. The control group consisted of 20 healthy term infants (40 ears). VEMP recordings were performed, and

Seyra Erbek; Zeynel Gokmen; Servet Ozkiraz; Selim S. Erbek; Aylin Tarcan; Levent N. Ozluoglu

2009-01-01

90

Modeling the vestibular evoked myogenic potential  

Microsoft Academic Search

Measuring the vestibular evoked myogenic potential (VEMP) promises to become a routine method for assessing vestibular function, although the technique is not yet standardized. To overcome the problem that the VEMP amplitude depends not only on the inhibition triggered by the acoustic stimulation of the vestibular end organs in the inner ear, but also on the tone of the muscle

Bernd Lütkenhöner; Wolfgang Stoll; Türker Basel

2010-01-01

91

Evoked Cortical Potentials and Information Processing.  

National Technical Information Service (NTIS)

The present report details the results of five separate experiments. Experiment I examines the visual evoked potential (VEP) to a target stimulus when it is perceptually masked by a second stimulus, and again when it is disinhibited. In experiment II, the...

J. L. Andreassi J. A. Gallichio N. E. Young

1977-01-01

92

Vestibular-Evoked Myogenic Potentials as a Test of Otolith Function  

Microsoft Academic Search

Objectives: To evaluate the use of 75 auditory clicks rather than the usual 100–256 for production of the vestibular-evoked myogenic potential (VEMP) response and to assess if the VEMP correlates with measures of cochlear function such as hearing loss (decibels on pure-tone testing) or auditory brainstem response (ABR). Subjects and Methods: Testing of the VEMP was carried out on 24

Khalid Al-Sebeih; Anthony Zeitouni

2002-01-01

93

Brain volume analyses and somatosensory evoked potentials in multiple system atrophy  

Microsoft Academic Search

We investigated a progression of brain atrophy and somatosensory system dysfunction in multiple system atrophy (MSA). Subjects\\u000a were 21 MSA patients [12 MSA-C (cerebellar type) and 9 MSA-P (parkinsonism type)]. The relative volumes of cerebrum, brainstem\\u000a and cerebellum to the intracranial volume were obtained from three-dimensional computed tomography (3D-CT) of the brain. The\\u000a median nerve somatosensory evoked potentials (SEPs) were

Satoko Miyatake; Hitoshi Mochizuki; Tetsuji Naka; Yoshikazu Ugawa; Hajime Tanabe; Daisuke Kuzume; Mikiya Suzuki; Katsuhisa Ogata; Mitsuru Kawai

2010-01-01

94

Nasopharyngeal electrode recording of somatosensory evoked potentials as an indicator in brain death.  

PubMed

Median nerve somatosensory evoked potentials were recorded in 28 comatose patients, eight of whom were progressing from coma to eventual brain death and in 11 brain dead patients using electrodes over the scalp, neck and nasopharynx (nasopharyngeal electrode). This recording technique was used to assess the different derivation of brainstem P14 wave activity. It showed that in the midfrontal scalp to the nasopharynx derivation a clear P14 was present in all comatose patients. This component disappeared during the passage from coma to brain death. In a separate group, simultaneous direct recordings in the vicinity of the dorsal column nuclei and with a nasopharyngeal electrode were made in five patients undergoing neurosurgical procedures at the craniocervical junction with the same somatosensory evoked potential monitor. We found that the P14 recorded with the nasopharyngeal electrode in the neurosurgical patients corresponded in latency and morphology with the P14 recorded directly on the surface of the craniocervical junction and more specifically in the vicinity of the nucleus cuneatus. The nasopharyngeal electrode provides non-invasive access to the ventral brainstem at the medullo-pontine level and the disappearance of the P14 shows a clear sign of involvement of the craniocervical junction in brain dead patients. Our study showed that with a simple montage the nasopharyngeal electrode is an effective non-invasive monitor for brainstem activity and can be used as an early diagnostic indicator of brainstem death. PMID:10050218

Roncucci, P; Lepori, P; Mok, M S; Bayat, A; Logi, F; Marino, A

1999-02-01

95

Evoked potential changes from 13 weeks of simulated toluene abuse in rats.  

PubMed

Fischer 344 rats were exposed to 8000 ppm toluene vapor in an 'abuse' paradigm for 13 weeks to develop an animal model for 'solvent neurotoxicity.' Exposures to toluene were multiple and short (15 to 35 min), adjusted according to tolerance. Although body weight was reduced 23% from controls, the toluene-exposed rats appeared healthy. Evoked potentials taken postexposure were, however, mildly to severely affected. Flash-evoked potentials were slow and topographically disorganized; 10 kHz tone-pip auditory brainstem responses (ABRs) had severe loss of power and loss of detail. Click and 30 kHz ABRs, somatosensory-evoked potentials, and caudal nerve action potentials were less affected. No neuropathologic changes were detected by light microscopy (perfusion fixation, special stains). Thus, postexposure multimodal functional effects were readily detected after subchronic, severe episodic exposures to toluene. PMID:2377668

Mattsson, J L; Gorzinski, S J; Albee, R R; Zimmer, M A

1990-07-01

96

Vestibular Evoked Myogenic Potentials in Newborns  

Microsoft Academic Search

This study presents a novel method for recording vestibular evoked myogenic potential (VEMP) in newborns, used to investigate the maturation of sacculocollic reflex at birth.Twenty full-term newborns aged 2–5 days old were enrolled in this study. During natural sleep, each newborn underwent distortion product otoacoustic emission test, and VEMP test using the head rotation method. For comparison, 20 healthy adults

Chun-Nan Chen; Shou-Jen Wang; Chi-Te Wang; Wu-Shiun Hsieh; Yi-Ho Young

2007-01-01

97

Wireless Vestibular Evoked Myogenic Potentials System  

Microsoft Academic Search

Existing commercial vestibular evoked myogenic potentials (VEMP) testing systems are cabled systems, which impede certain experiments, particularly those that involve motion and rotation of the patient. This paper presents an autonomous wireless system to record VEMPs. The system uses IMEC's 60 muW 60 nV\\/VHz biopotential readout front-end to extract the electromyogram (EMG). It uses IMEC's low power processing and wireless

T. Torfs; R. F. Yazicioglu; P. Merken; B. Gyselinckx; R. Puers; R. Vanspauwen; F. L. Wuyts; C. Van Hoof

2007-01-01

98

Vestibular evoked myogenic potential in vestibular neuritis  

Microsoft Academic Search

This study wants to show the diagnostic value of vestibular evoked myogenic potential (VEMP) in the diagnosis of vestibular\\u000a neuritis (VN), independently of the caloric test results. Twenty patients were enrolled with acute vertigo caused by VN. VEMP\\u000a was tested with the binaural simultaneous stimulation method. Surface electromyographic activity was recorded in the supine\\u000a patients from symmetrical sites over the

Giuseppe Nola; Luca Guastini; Barbara Crippa; Marco Deiana; Renzo Mora; Giovanni Ralli

99

Evoked potentials in children with Wilson's disease  

Microsoft Academic Search

We assessed multimodal evoked potentials (EPs) in 13 children with newly diagnosed neurologically symptomatic Wilson's disease (WD) and in their first degree symptom-free relatives, consisting of seven presymptomatic and 15 asymptomatic siblings and 22 asymptomatic parents. EP abnormalities of at least one modality and one side stimulation were observed in 38.5% of patients, 42.9% of presymptomatic siblings, 21.4% of asymptomatic

Meral Topcu; Mehmet Akif Topcuoglu; Gulsen Kose; Gulay Nurlu; Guzide Turanli

2002-01-01

100

Obtaining single stimulus evoked potentials with wavelet denoising  

Microsoft Academic Search

We present a method for the analysis of electroencephalograms (EEG). In particular, small signals due to stimulation, so-called evoked potentials (EPs), have to be detected in the background EEG. This is achieved by using a denoising implementation based on the wavelet decomposition. One recording of visual evoked potentials, and recordings of auditory evoked potentials from four subjects corresponding to different

R. Quian Quiroga

2000-01-01

101

[Acoustic evoked potentials (AEP) in obstructive sleep apnea syndrome].  

PubMed

Patients with obstructive sleep apnea syndrome (OSAS) present upper airway obstruction during sleep which can be documented by electromyography. The cause of weakness in oropharyngeal muscles is still unknown. Lesions of pons and medulla oblongata have to be expected. Brainstem auditory evoked potentials (BAEP) may indicate pathological changes in these regions. Several studies described normal BAEP in OSAS-patients. Moderate forms of OSAS as well as central sleep apnea syndromes were investigated, however. In our study 20 patients (17 men, 3 women, mean age 53.9 +/- 2.1 ys) with severe OSAS (apnea/hypopnea-index: 34.2 +/- 14.1/h, part of O2-saturation < or = 90% during sleep (SaO2 < or = 90%): 13.5 +/- 4.2%, minimal nocturnal O2-saturation: 78.0 +/- 2.5%) before starting nCPAP-therapy were investigated. BAEP were elicited after applying clicks 70 dB above threshold to each ear. Means of single wave latencies as well as interpeak latencies (I-V, I-III, III-V) were delayed significantly compared to normal controls. Main prolongations were seen regarding wave latency I (p < or = 0.001) and-interpeak latency I-V (p < or = 0.001). Prolongation of interpeak latencies (mean +/- 2.5 SD) of one or two sides could be demonstrated in 12 out of 20 patients. Pontomesencephal lesions (9 patients) dominated. There was no connection with respiratory parameters. As against pathological BAEP changes correlated with the duration of the disease. In conclusion pathological BAEP indicating brainstem lesions were seen in 60% of the examined OSAS-patients. Mesencephal lesions dominated, number of lesions increased with duration of disease. Therefore pathological findings have not to be considered as cause but as a result of hypoxemia in OSAS. Pathological BAEP may reveal a higher risk for cerebrovascular stroke. Therefore these patients should be leaded to further cerebrovascular investigation. PMID:9091889

Kotterba, S; Rasche, K

1996-12-01

102

Glycerol affects vestibular evoked myogenic potentials in Meniere's disease  

Microsoft Academic Search

Objectives: to show that abnormal vestibular evoked myogenic potentials on the sternocleidomastoid muscle (SCM) in patients with unilateral Meniere's disease are caused by endolymphatic hydrops. Subjects: six normal volunteers and 17 patients with unilateral Meniere's disease were examined. Methods: click-evoked myogenic potentials were recorded with surface electrodes over each SCM. Responses evoked by clicks recorded after oral administration of glycerol

Toshihisa Murofushi; Masaki Matsuzaki; Hideki Takegoshi

2001-01-01

103

Multiple Color Stimulus Induced Steady State Visual Evoked Potentials.  

National Technical Information Service (NTIS)

Steady state visual evoked potentials (SSVEP) are of the characteristics of high SNR and effectiveness in short-term identification of evoked responses. In most of the SSVEP experiments, single high frequency stimuli are used. To characterize the complex ...

M. Cheng X. Gao S. Gao D. Xu

2001-01-01

104

Contact heat evoked potentials in normal subjects.  

PubMed

Laser-evoked potentials are widely used to investigate nociceptive pathways. The newly developed contact heat stimulator for evoking brain response has the advantages of obtaining reliable scalp potentials and absence of cutaneous lesions. This study aimed to identify the most appropriate stimulation site with consistent cortical responses, and to correlate several parameters of the contact heat evoked potentials (CHEPs) with age, gender, and body height in normal subjects. CHEPs were recorded at Cz with a contact heat stimulator (Medoc, Israel) in 35 normal controls. The subjects were asked to keep eyes open and remain alert. The baseline temperature was 32 degrees C, and stimulation peak heat intensity of 51 degrees C was applied to five body sites: bilateral forearm, right dorsum hand, right peroneal area, and right dorsum foot. Reproducible CHEPs were recorded more frequently when stimulated at volar forearm (62.5%) than at the lower limbs (around 40%). The first negative peak latency (N1) was 370.1 +/- 20.3 ms, first positive peak latency (P1) was 502.4 +/- 33.0 ms, and peak to peak amplitude was 10.2 +/- 4.9 microV with stimulation of the forearm. Perceived pain intensity was not correlated with the presence or amplitude of CHEPs. No gender or inter-side differences were observed for N1 latency and N1-P1 amplitude. Also, no correlation was noted between N1 and age or body height. These results support future clinical access of CHEPs as a diagnostic tool. PMID:16995598

Chen, I-An; Hung, Steven Wu; Chen, Yu-Hsien; Lim, Siew-Na; Tsai, Yu-Tai; Hsiao, Cheng-Lun; Hsieh, Hsiang-Yao; Wu, Tony

2006-09-01

105

Pattern reversal evoked potentials in infantile spasms.  

PubMed

Visual evoked potentials in response to sinusoidal gratings of various spatial frequencies, alternating in contrast at 8 Hz were recorded from infants affected by an idiopathic form of infantile spasms (West syndrome). In two infants in whom the spasms began at 3 and 5 months of age, respectively, the VEP's were found to be depressed in amplitude at and around a spatial frequency of 3 and 5 c/deg, respectively. This midfrequency depression, which has never been reported in the literature for normal infants, suggests that infantile spasms in idiopathic patients may interfere at least temporarily with the development of visual function. PMID:6480435

Taddeucci, G; Fiorentini, A; Pirchio, M; Spinelli, D

1984-01-01

106

Spectral and synchrony differences in auditory brainstem responses evoked by chirps of varying durations.  

PubMed

The chirp-evoked ABR has been termed a more synchronous response, referring to the fact that rising-frequency chirp stimuli theoretically compensate for temporal dispersions down the basilar membrane. This compensation is made possible by delaying the higher frequency content of the stimulus until the lower frequency traveling waves are closer to the cochlea apex. However, it is not yet clear how sensitive this temporal compensation is to variation in the delay interval. This study analyzed chirp- and click-evoked ABRs at low intensity, using a variety of tools in the time, frequency, and phase domains, to measure synchrony in the response. Additionally, this study also examined the relationship between chirp sweep rate and response synchrony by varying the delay between high- and low-frequency portions of chirp stimuli. The results suggest that the chirp-evoked ABRs in this study exhibited more synchrony than the click-evoked ABRs and that slight gender-based differences exist in the synchrony of chirp-evoked ABRs. The study concludes that a tailoring of chirp parameters to gender may be beneficial in pathologies that severely affect neural synchrony, but that such a customization may not be necessary in routine clinical applications. PMID:20968361

Petoe, Matthew A; Bradley, Andrew P; Wilson, Wayne J

2010-10-01

107

Acoustic Responses after Total Destruction of the Cochlear Receptor: Brainstem and Auditory Cortex  

NASA Astrophysics Data System (ADS)

Acoustically evoked neural activity has been recorded from the brainstem and auditory cortex of guinea pigs after complete destruction of the organ of Corti by the aminoglycosidic antibiotic amikacin. These responses to sound differ in important respects from the evoked potentials normally recorded from the auditory pathways. At the brainstem level they resemble the potentials reported by others after stimulation of the vestibular nerve.

Cazals, Yves; Aran, Jean-Marie; Erre, Jean-Paul; Guilhaume, Anne

1980-10-01

108

Significance of Vestibular Evoked Myogenic Potentials in Peripheral Vestibulopathy  

Microsoft Academic Search

Background : Loud monaural clicks evoke myogenic potentials in the tonically contracting ipsilateral sternocleido - mastoid muscle. Clinical studies have suggested that these myogenic potentials are of vestibular origin, especially infe - rior vestibular nerve. Neurophysiological experimental studies also suggest that they are most likely to be of saccular origin. These potentials are called vestibular evoked myogenic potentials (VEMPs). Vestibular

Hyun-Young Kim; Hee-Tae Kim; Seung-Hyun Kim; Juhan Kim; Myung-Ho Kim; Ki-Bum Sung

109

Long-Term Evolution of Brainstem Electrical Evoked Responses to Sound after Restricted Ablation of the Auditory Cortex  

PubMed Central

Introduction This study aimed to assess the top-down control of sound processing in the auditory brainstem of rats. Short latency evoked responses were analyzed after unilateral or bilateral ablation of auditory cortex. This experimental paradigm was also used towards analyzing the long-term evolution of post-lesion plasticity in the auditory system and its ability to self-repair. Method Auditory cortex lesions were performed in rats by stereotactically guided fine-needle aspiration of the cerebrocortical surface. Auditory Brainstem Responses (ABR) were recorded at post-surgery day (PSD) 1, 7, 15 and 30. Recordings were performed under closed-field conditions, using click trains at different sound intensity levels, followed by statistical analysis of threshold values and ABR amplitude and latency variables. Subsequently, brains were sectioned and immunostained for GAD and parvalbumin to assess the location and extent of lesions accurately. Results Alterations in ABR variables depended on the type of lesion and post-surgery time of ABR recordings. Accordingly, bilateral ablations caused a statistically significant increase in thresholds at PSD1 and 7 and a decrease in waves amplitudes at PSD1 that recover at PSD7. No effects on latency were noted at PSD1 and 7, whilst recordings at PSD15 and 30 showed statistically significant decreases in latency. Conversely, unilateral ablations had no effect on auditory thresholds or latencies, while wave amplitudes only decreased at PSD1 strictly in the ipsilateral ear. Conclusion Post-lesion plasticity in the auditory system acts in two time periods: short-term period of decreased sound sensitivity (until PSD7), most likely resulting from axonal degeneration; and a long-term period (up to PSD7), with changes in latency responses and recovery of thresholds and amplitudes values. The cerebral cortex may have a net positive gain on the auditory pathway response to sound.

Lamas, Veronica; Alvarado, Juan C.; Carro, Juan; Merchan, Miguel A.

2013-01-01

110

Obtaining single stimulus evoked potentials with Wavelet Denoising  

Microsoft Academic Search

We present a method for the analysis of electroencephalograms (EEG).\\u000a In particular, small signals due to stimulation, so called evoked potentials,\\u000ahave to be detected in the background EEG. This is achieved by using a\\u000adenoising implementation based on the wavelet decomposition. One recording of\\u000avisual evoked potentials, and recordings of auditory evoked potentials from 4\\u000asubjects corresponding to different

R. Quian Quiroga; John von Neumann

2000-01-01

111

Modeling and estimation of single evoked brain potential components  

Microsoft Academic Search

Presents a novel approach to solving the single-trial evoked-potential estimation problem. Recognizing that different components of an evoked potential complex may originate from different functional brain sites and can be distinguished according to their respective latencies and amplitudes, the authors propose an estimation approach based on identification of evoked potential components on a single-trial basis. The estimation process is performed

Daniel H. Lange; Hillel Pratt; Gideon F. Inbar

1997-01-01

112

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

113

Pattern visual evoked potentials in cases of ambiguous acuity loss  

Microsoft Academic Search

Thirty patients were referred to our visual evoked potential laboratory with complaints of profound acuity loss in one or both eyes. However, the objective ophthalmologic findings were normal, including pupillary reaction, and anterior segment and fundus examinations. Transient visual evoked potentials to a 2.3-c\\/deg sinusoidal grating pattern were found to be present in 26 of these 30 patients. Visual evoked

Phyllis Bobak; Priti Khanna; James Goodwin; Mitchell Brigell

1993-01-01

114

Effect of middle ear effusion on the brain-stem auditory evoked response of Cavalier King Charles Spaniels.  

PubMed

Brain-stem auditory evoked responses (BAER) were assessed in 23 Cavalier King Charles Spaniels with and without middle ear effusion at sound intensities ranging from 10 to 100 dB nHL. Significant differences were found between the median BAER threshold for ears where effusions were present (60 dB nHL), compared to those without (30 dB nHL) (P=0.001). The slopes of latency-intensity functions from both groups did not differ, but the y-axis intercept when the x value was zero was greater in dogs with effusions (P=0.009), consistent with conductive hearing loss. Analysis of latency-intensity functions suggested the degree of hearing loss due to middle ear effusion was 21 dB (95% confidence between 10 and 33 dB). Waves I-V inter-wave latency at 90 dB nHL was not significantly different between the two groups. These findings demonstrate that middle ear effusion is associated with a conductive hearing loss of 10-33 dB in affected dogs despite the fact that all animals studied were considered to have normal hearing by their owners. PMID:21194995

Harcourt-Brown, Thomas R; Parker, John E; Granger, Nicolas; Jeffery, Nick D

2010-12-30

115

Visual evoked potentials in disproportionately growth-retarded human neonates  

Microsoft Academic Search

To study brain function in the neonatal period, disproportionately growth-retarded (n = 33) and appropriately grown (n = 21) infants were examined using Doppler flow velocities prenatally and visual evoked potentials postnatally. Visual evoked potentials recordings were made at gestation of 40 and 46 weeks. The group of growth-retarded infants had significantly prolonged latencies to both of the two major

C. Magnus Thordstein; Bo L Sultan; Margareta M Wennergren; Eva Törnqvist; Kaj G Lindecrantz; Ingemar Kjellmer

2004-01-01

116

Physiological mechanisms of habituation of visual evoked potentials  

Microsoft Academic Search

Experiments on cats showed that complete operative exclusion of the reticular formation by precollicular section prevents the development of habituation of evoked potentials in the primary visual projection area and lateral geniculate body. Similar results were obtained after postcollicular section of the mesencephalon. The phenomenon of habituation of visual evoked potentials is found in posttrigeminal preparations. It is postulated that

R. F. Makul'kin; Yu. F. Pedanov

1972-01-01

117

Serial visual evoked potential recordings in Alzheimer's disease  

Microsoft Academic Search

Primary presenile dementia slows the major positive component of the visual evoked potential to flash stimulation but does not affect the visual evoked potential to patterned stimulation. The progressive effect of Alzheimer's disease was followed in a 58 year old woman over three and a half years from the development of the earliest symptoms to complete mental incapacity. The pattern

G F A Harding; C E Wright; D C Rowan; E B Rolfe

1986-01-01

118

[Visually evoked potentials and visual acuity of the young child].  

PubMed

Interest in the development of visual acuity in young infants is increasing. At this age a reliable estimation of visual function is hazardous. This paper highlights the role of flash- and pattern evoked visual potentials. Flash evoked potentials are valuable in following development and/or recovery of visual acuity intra-individually as well as in providing an estimation of sensitiveness to light. Pattern evoked potentials may give an estimation of maturation of the visual system: these potentials also give an objective measurement of visual acuity. PMID:2799799

van Nieuwenhuizen, O

1989-06-01

119

Specialization of the auditory processing in harbor porpoise, characterized by brain-stem potentials  

NASA Astrophysics Data System (ADS)

Brain-stem auditory evoked potentials (BAEPs) were recorded from the head surface of the three awaked harbor porpoises (Phocoena phocoena). Silver disk placed on the skin surface above the vertex bone was used as an active electrode. The experiments were performed at the Karadag biological station (the Crimea peninsula). Clicks and tone bursts were used as stimuli. The temporal and frequency selectivity of the auditory system was estimated using the methods of simultaneous and forward masking. An evident minimum of the BAEPs thresholds was observed in the range of 125-135 kHz, where the main spectral component of species-specific echolocation signal is located. In this frequency range the tonal forward masking demonstrated a strong frequency selectivity. Off-response to such tone bursts was a typical observation. An evident BAEP could be recorded up to the frequencies 190-200 kHz, however, outside the acoustical fovea the frequency selectivity was rather poor. Temporal resolution was estimated by measuring BAER recovery functions for double clicks, double tone bursts, and double noise bursts. The half-time of BAERs recovery was in the range of 0.1-0.2 ms. The data indicate that the porpoise auditory system is strongly adapted to detect ultrasonic closely spaced sounds like species-specific locating signals and echoes.

Bibikov, Nikolay G.

2002-05-01

120

Contact heat evoked potentials using simultaneous EEG and fMRI and their correlation with evoked pain  

Microsoft Academic Search

BACKGROUND: The Contact Heat Evoked Potential Stimulator (CHEPS) utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm\\/heat thresholds of receptors expressed by A? and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials

Katherine Roberts; Anastasia Papadaki; Carla Gonçalves; Mary Tighe; Duncan Atherton; Ravikiran Shenoy; Donald McRobbie; Praveen Anand

2008-01-01

121

Transcranial magnetic motor-evoked potentials in scoliosis surgery.  

PubMed

Spinal cord monitoring using SSEPs is an accepted adjunct in the surgical correction of spinal deformities, but does not directly assess motor function. Motor-evoked potentials have been introduced in an effort to meet this important need. In this series of 18 patients, the feasibility of intraoperative monitoring using transcranial magnetic motor-evoked potentials is documented. The potential value of this neurophysiologic monitoring technique, as well as the pitfalls in interpretation, are reviewed. PMID:8584459

Glassman, S D; Zhang, Y P; Shields, C B; Johnson, J R; Linden, R D

1995-10-01

122

USE OF SENSORY EVOKED POTENTIALS IN NEUROTOXICITY TESTING OF WORKERS  

EPA Science Inventory

Electrophysiological measures appropriate for use in neurotoxicity testing of workers are briefly reviewed. These measures include auditory, visual and somatosensory evoked potentials. Relevant human studies are reviewed. Selection criteria, strengths and weaknesses are discussed...

123

Aging effect on galvanic vestibular-evoked myogenic potentials  

Microsoft Academic Search

ObjectiveThis study compared the characteristic parameters of vestibular-evoked myogenic potentials (VEMPs) via galvanic vestibular stimulation (GVS) in healthy subjects of various ages to measure the effect of aging on GVS-VEMPs.

Chih-Ming Chang; Po-Wen Cheng; Yi-Ho Young

2010-01-01

124

Development of vestibular evoked myogenic potentials in early life  

Microsoft Academic Search

ObjectiveThis study applied vestibular evoked myogenic potential (VEMP) test in full-term newborns younger than 2 weeks, to investigate the development and maturation of the sacculo-collic reflex in early life.

Yi-Ho Young; Chun-Nan Chen; Wu-Shiun Hsieh; Shou-Jen Wang

2009-01-01

125

Transient Evoked Potential in a Critical Event Detection Task.  

National Technical Information Service (NTIS)

An experiment was designed to investigate late positive components of the transient evoked potential elicited by detection of a perceptually complex critical event. Areas of investigation included spatial distribution, motor response effects, stimulus dur...

S. A. Huddleson

1984-01-01

126

The Effect of Attention on Auditory Evoked Potentials.  

National Technical Information Service (NTIS)

Click-evoked potentials were recorded from unanesthetized cats with electrodes chronically implanted in the auditory cortex, cochlear nucleus, and round window. The clicks (irrelevant stimuli) were presented continuously as background before, during, and ...

L. C. Oatman

1968-01-01

127

SN10 auditory evoked potential revisited.  

PubMed

The slow brainstem response (SN10) was originally described as a slow negative wave occurring at a latency of 10 msec post stimulus onset. In the late 1970s and early 1980s it was considered to be promising for estimating hearing thresholds at low frequencies. However, there have been controversies regarding waveform description, recording stimulus parameters, and factors affecting the response. Consequently, the SN10 has not become a popular clinical test for estimating hearing thresholds electrophysiologically. However, recent observation of ABR waveforms using low-frequency stimuli and broad-band filtering indicate that the negative wave after wave V can be highly identifiable. This wave in many instances is the SN10. Therefore, this article was designed to review various aspects of the SN10 to make clinicians more aware of its possible applications in estimating low-frequency hearing thresholds. PMID:1882965

Tawfik, S; Musiek, F E

1991-05-01

128

Visual evoked potentials and electroretinography in brain-dead patients  

Microsoft Academic Search

Visual evoked potentials and electroretinograms were elicited by light-emitting diode stimulation and recorded simultaneously, with cephalic and noncephalic references, in 30 normal subjects and in 30 brain-dead patients. A characteristic pattern was found in the group of patients: when a cephalic reference was used for both visual evoked potentials and the electroretinogram, the a- and b-waves of the electroretinogram were

Calixto Machado; Rosaralis Santiesteban; Orlando García; Pedro Coutin; Miguel A. Beurgo; Jose Román; Juan Miranda; Juana Suárez; Gert Pfurtscheller

1993-01-01

129

The British Columbia's Children's Hospital tone-evoked auditory brainstem response protocol: how long do infants sleep and how much information can be obtained in one appointment?  

PubMed

There are few published reports providing quantitative information of clinical feasibility for tone-evoked auditory brainstem response (ABR) protocols. In this study, the authors reviewed charts of 188 ABR assessments during a 20-mo period: 116 sedated (median age, 23 mos) and 72 nonsedated (median age, 4 mos). Fifty-one percent of infants had normal thresholds. The average amount of sleep time was 58 mins for sedated assessments, during which an average of 7.6 measures were obtained; nonsedated assessments averaged 49 mins with 6.2 measures obtained. Thus, a substantial amount of both test time and information about hearing can be obtained within one ABR appointment. PMID:20473179

Janssen, Renée M; Usher, Laurie; Stapells, David R

2010-10-01

130

Tone burst–galvanic ratio of vestibular evoked myogenic potential amplitudes: A new parameter of vestibular evoked myogenic potential?  

Microsoft Academic Search

ObjectiveTo clarify whether the ratio of tone burst vestibular evoked myogenic potential (VEMP) amplitude to galvanic (electric) VEMP amplitude can be a useful indicator of peripheral vestibular disorders, especially labyrinthine disorders.

Toshihisa Murofushi; Shinichi Iwasaki; Hidenori Ozeki; Munetaka Ushio; Yasuhiro Chihara

2007-01-01

131

Vestibular evoked potentials in response to direct unilateral mechanical stimulation.  

PubMed

Evoked potentials produced by direct unilateral mechanical stimulation of the cannulated horizontal semicircular canal were investigated parametrically in anesthetized adult cats (40 mg/kg pentobarbital). Stimuli were fluid pressure pulses in a closed hydraulic system (no net flow), which was coupled to the lateral semicircular canal near the ampulla. Hydraulic waveform output and fluid pressure was monitored in situ via a parallel hydraulic circuit during experiments. Maximum fluid displacement at the level of the horizontal canal was 0.025 microliters. The intensity, duration, and presentation rate of the stimulus were varied during experiments. Field potentials were recorded differentially using subdermal electrodes, with the active lead in the region of the mastoid referenced to a distant nasal site. A total of 256 trials was accumulated for each run using an averaging computer. Evoked responses were physiologically vulnerable and reproducible, with little variance among animals. Response amplitude increased monotonically until saturation was noted and responses followed the temporal structure of the pressure wave. Polarity reversal with differing electrode placement suggests that the generator site lies within the mastoid. Further, intense broad-band acoustic stimuli and eighth nerve sectioning did not affect the vestibular evoked potentials, but could be shown to abolish the auditory evoked potentials. Results of these experiments support the notion that vestibular evoked potentials are related to the first derivative of the pressure pulse waveforms. Future experiments will be directed toward the assessment of vestibular physiology and pharmacology with this evoked response method. PMID:2496377

Coale, F S; Walsh, E J; McGee, J; Konrad, H R

1989-03-01

132

The utility of multimodal evoked potentials in multiple sclerosis prognostication.  

PubMed

The ability to predict disability development in multiple sclerosis (MS) is limited. While abnormalities of evoked potentials (EP) have been associated with disability, the prognosticating utility of EP in MS remains to be fully elucidated. The present study assessed the utility of multimodal EP as a prognostic biomarker of disability in a cohort of clinically heterogeneous MS patients. Median and tibial nerve somatosensory, visual, and brainstem auditory EP were performed at initial assessment on 63 MS patients (53 relapsing-remitting and 10 secondary progressive) who were followed for an average of 2years. A combined EP score (CEPS) was calculated consisting of the total number of abnormal EP tests, and was correlated with the Expanded Disability Status Scale (EDSS) at baseline and follow-up. There was a significant correlation between multimodal EP and baseline and follow-up EDSS. Specifically, tibial nerve P37 latencies correlated with EDSS (RBASELINE=0.49, p<0.01; RFOLLOW-UP=0.47, p<0.01), as did the median nerve N13 (RBASELINE=0.40, p<0.01; RFOLLOW-UP=0.35, p<0.05) and N20 latencies (RBASELINE=0.43, p<0.01; RFOLLOW-UP=0.47, p<0.01), and P100 full-field (RBASELINE=0.50, p<0.001; RFOLLOW-UP=0.45, p<0.001) and central field latencies (RBASELINE=0.60, p<0.001; RFOLLOW-UP=0.50, p<0.001). In addition, there was a significant correlation between the CEPS with baseline (R=0.65, p<0.001) and follow-up (R=0.57, p<0.01) EDSS. In contrast, white matter disease burden, as measured by T2 lesion load, exhibited a weaker correlation with EDSS (RBASELINE=0.28, p<0.05). In conclusion, these findings suggest that abnormalities of EP, as quantified by the novel CEPS, may be a useful biomarker for prognosticating clinical disability in MS, and may aid in the quantification of MS disease severity and in guiding therapeutic decisions. PMID:23827173

Ramanathan, Sudarshini; Lenton, Kerry; Burke, Therese; Gomes, Lavier; Storchenegger, Karen; Yiannikas, Con; Vucic, Steve

2013-07-01

133

CHRONIC DIETARY EXPOSURE WITH INTERMITTENT SPIKE DOSES OF CHLORPYRIFOS FAILS TO ALTER BRAINSTEM AUDITORY EVOKED RESPONSE (BAERS) IN RATS.  

EPA Science Inventory

Human exposure to pesticides is often characterized by chronic low level exposure with intermittent spiked higher exposures. Cholinergic transmission is involved in auditory structures in the periphery and the brainstem and is altered following chlorpyrifos exposure. This study e...

134

[Objective auditory evaluation by evoked potentials].  

PubMed

We have analyzed 1300 Auditory Brain-Stem Response Audiometry exams. The patients were distributed according to criteria related to age, clinical presentation, hearing impairment risk-factors and hearing thresholds. The results were divided into five groups of hearing thresholds: normal hearing (threshold response obtained up to 25 dBHL); mild hearing loss (25-50 dBHL); moderate hearing loss (50-70 dBHL); severe hearing loss (70-90 dBHL); and without response to acoustic stimuli. We have studied the risk-factors related to gestation, delivery and neonatal period, family history of hearing loss, hearing apparatus malformations, craniofacial anomalies, certain modalities of infectious diseases, hearing impairment associated syndromes, and the use of some kind of drugs. Cerebral palsy, neuropsychomotor development retardation and cases without known antecedents were also studied. The main results of our study show: 82.8% incidence of hearing impairment; the late performance of examinations to evidence a definite hearing loss as 54.1% of the examined patients were at ages ranging from one to three years old; 54.0% of total cases have not presented any language development; the risk-factor "Congenital Rubeola" has the expressive incidence of 14.8% and the distribution of this value into hearing threshold ranges has shown an exponential increase which demonstrates a close correlation between that disease and hearing impairment. PMID:8147741

Seixas, R R; Fasolo, M I; Moreira, R N

1993-12-01

135

Enhanced neuronal excitability in adult rat brainstem causes widespread repetitive brainstem depolarizations with cardiovascular consequences.  

PubMed

The brainstem of the adult rat is relatively resistant to spreading depolarization (SD) but after enhancement of excitability SD can be evoked by local application of KCl. In the present experiments, we observed that the enhanced excitability even triggers prolonged periods of repetitive depolarizations (RDs), which elicit significant cardiovascular changes. In contrast to KCl-evoked SDs with amplitudes of ?24?mV and spreading velocity of 4?mm/min, spontaneous RDs had amplitudes of 7 to 12?mV, propagated up to 30 times faster than KCl-evoked SDs, and depolarized larger brainstem areas including the contralateral side. Similarly as SD, RDs depended on glutamatergic neurotransmission and were blocked by MK-801 or by the calcium channel blocker agatoxin. They depended on sodium channels and were blocked by tetrodotoxin. Functionally, the invasion of RDs into the spinal trigeminal and other nuclei evoked bursts of action potentials, indicating that specific neuronal systems are affected. In fact, during episodes of RDs the blood pressure and the local blood flow at the surface of the brainstem and the cortex increased substantially. Brainstem RDs did not propagate into the cerebral cortex. We propose to consider brainstem RPs as a pathophysiological mechanism whose significance for brainstem disease states should be further explored. PMID:22453631

Richter, Frank; Bauer, Reinhard; Ebersberger, Andrea; Lehmenkühler, Alfred; Schaible, Hans-Georg

2012-03-28

136

Ocular vestibular evoked myogenic potentials in superior canal dehiscence  

Microsoft Academic Search

Objective:Patients with superior canal dehiscence (SCD) have large sound-evoked vestibular reflexes with pathologically low threshold. We wished to determine whether a recently discovered measure of the vestibulo-ocular reflex—the ocular vestibular evoked myogenic potential (OVEMP)—produced similar high-amplitude, low-threshold responses in SCD, and could differentiate patients with SCD from normal control patients.Methods:Nine patients with CT-confirmed SCD and 10 normal controls were stimulated

S M Rosengren; S T Aw; G M Halmagyi; N P McAngus Todd; J G Colebatch

2008-01-01

137

Vestibular evoked myogenic potentials: Past, present and future  

Microsoft Academic Search

Since the first description of sound-evoked short-latency myogenic reflexes recorded from neck muscles, vestibular evoked myogenic potentials (VEMPs) have become an important part of the neuro-otological test battery. VEMPs provide a means of assessing otolith function: stimulation of the vestibular system with air-conducted sound activates predominantly saccular afferents, while bone-conducted vibration activates a combination of saccular and utricular afferents. The

S. M. Rosengren; M. S. Welgampola; J. G. Colebatch

2010-01-01

138

Ocular Vestibular Evoked Myogenic Potential Using Different Test Stimuli  

PubMed Central

Aim. Ocular Evoked Myogenic Potential (oVEMP) are short latency potentials evoked by higher acoustic stimulation. In this study, we aimed at comparing the click, 500?Hz mixed modulated, and 500?Hz short duration tone burst stimuli using oVEMP. Material. Click, 500?Hz mixed modulated and 500?Hz short duration tone burst stimuli were used for the study. Method. Conventional sampling and conveneint study design were used. Sixty healthy subjects underwent contralateral oVEMP testing maintaining 30 degrees upward gaze. Single channel electrode montage was applied to record oVEMP response. Results. On statistical analysis the three stimuli evoked equal response rates (100%), and when latency of n1 and p1 and peak-peak amplitude were compared, the click evoked showed significantly early latency and lower peak-peak amplitude than the 500?Hz stimuli. Five hundred Hz stimuli did not show significant difference in latency and peak-peak amplitude of n1-p1. Discussion. Thus, 500?Hz stimuli can evoke better latency and peak-peak amplitude. oVEMP has good clinical significance in diagnosing subjects with vestibular dysfunction. To add to the sensitivity of the oVEMP test, 500?Hz stimuli may also be used as it can evoke better oVEMP responses in clinical population with good morphology.

Deepak, Dessai Teja; Bhat, Jayashree S.; Kumar, Kaushlendra

2013-01-01

139

Suboccipital craniotomy for Chiari I results in evoked potential conduction changes  

PubMed Central

Background: Management of Chiari I is controversial, in part because there is no widely used quantitative measurement of decompression. It has been demonstrated that brainstem auditory evoked responses (BAER) and somatosensory evoked potentials (SSEP) have decreased conduction latencies after wide craniectomy. We analyzed these parameters in a suboccipital craniectomy/craniotomy procedure. Methods: Thirteen consecutive patients underwent suboccipital decompression for treatment of symptomatic Chiari I. Craniectomy was restricted to the inferior aspect of the nuchal line, and in most cases the bone flap was replaced. Neuronal conduction was monitored continuously with median nerve somatosensory evoked potentials (M-SEP), posterior tibial nerve somatosensory evoked potentials (T-SEP), BAER, or a combination. The M-SEP N20, T-SEP P37, and BAER V latencies were recorded at four milestones – preoperatively, following craniotomy, following durotomy, and following closure. Results: Five males and eight females, with average age of 9 years, were studied. Clinical improvement was noted in all 13 patients. M-SEP N20 latency decreased from a mean of 18.55 at baseline to 17.75 ms after craniotomy (P = 0.01); to 17.06 ms after durotomy (P = 0.01); and to 16.68 ms after closing (P = 0.02). T-SEP P37 latency did not change significantly. BAER V latency decreased from a mean of 6.25 ms at baseline to 6.14 ms after craniotomy (P = 0.04); to 5.98 ms after durotomy (P = 0.01); and to 5.95 ms after closing (P = 0.45). Conclusion: Significant improvements in conduction followed both craniectomy and durotomy. Bone replacement did not affect these results.

Chen, Jason A.; Coutin-Churchman, Pedro E.; Nuwer, Marc R.; Lazareff, Jorge A.

2012-01-01

140

[Effects, on early auditory evoked potentials, of road traffic noise, of benzodiazepine and their combination].  

PubMed

In this study, 30 young men and 30 young women (with the same proportion of anxious persons in each group) were submitted, in random order, to: i) a road traffic noise of 75 dBA for 15 min; ii) this same noise for 15 min, having ingested 0.25 mg of alprazolam (Xanax*) 1 h before; iii) uniquely 0.25 mg of alprazolam. The auditory brainstem evoked potentials (ABEP) were taken before and after exposure to noise (for the non-noise case, we respected the same time schedule). The alprazolam had an effect on the cochlea and can be considered as a noise adaptation factor on the auditory pathways explored by the ABEP. PMID:9499939

Morizot-Martinet, S; Petiot, J C; Smolik, H J; Trapet, P; Gisselmann, A

1997-11-01

141

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...

142

Continuous somatosensory evoked potential monitoring in the NICU.  

PubMed

Monitoring of somatosensory evoked potentials (SSEP) of head-injured patients is a frequent and interesting topic in the neuroscience nursing arena. Often, however, nursing involvement in the recording of somatosensory evoked potentials has been limited to observing the once a week procedure and documenting patient outcome. Active nursing involvement and input in this fast moving area of research has been developed in a large midwestern neuroscience center where nurses in the NICU are responsible for the continuous monitoring (24 hours a day) of somatosensory evoked potentials of the brain-injured patient. These nurses are accountable for an accurate clinical assessment of the patient, placement and upkeep of the monitoring equipment, and evaluation of the waveform for abnormalities. The purpose and physiology of the monitoring process and the aspects of nursing care will be discussed in this article. PMID:3849566

Sherburne, E

1985-08-01

143

Deblurring visual evoked potentials using commercially available software.  

PubMed

Visual evoked potentials are useful clinical tools to study visual pathways of the brain. Although the temporal resolution is unsurpassed by other brain imaging technologies, the spatial resolution is diminished or blurred by the low conductance of the electrical signals through the skull. Methods have been proposed to improve the spatial resolution by downwardly projecting the electrical signals measured on the scalp to the surface of the cerebral cortex through the inverse solution of the equations governing static current flow. We describe the adaptation and combination of commercially available engineering software programs to solve this inverse problem and report the results of a sample run of the system. Before deblurring, the visual evoked potentials appeared to be diffusely localized over the posterior scalp. After deblurring, the visual evoked potentials were only found at the electrodes closest to the visual cortex, as would be predicted by our current knowledge of neuroanatomy. PMID:16563552

Zarkowski, Paul A; Shin, Chul-Jin; Holmes, Mark D

2006-04-01

144

Vestibular evoked myogenic potentials: optimal stimulation and clinical application  

Microsoft Academic Search

Summary  By easily stimulating the ear with loud sound and recording on tonically contracted neck muscles, vestibular evoked myogenic potential (VEMP) test can reflect inner ear function other than the cochlea and semicircular canal. This expands the test battery for clinicians to explore saccular disease, adding a potential usefulness to the sacculo-collic reflex. The ideal stimulation mode for VEMPs is as

Yi-Ho Young

2006-01-01

145

Vestibular evoked myogenic potential (VEMP) in patients with acoustic neuromas  

Microsoft Academic Search

Objective: To study the utility of VEMP (vestibular-evoked myogenic potential) in the diagnosis of acoustic neuromas.Methods: Eighteen patients with unilateral acoustic neuromas were subjected to this study. Myogenic potential responding to loud click stimuli was recorded at ipsilateral sternocleidomastoid muscle. A normal range of VEMP was obtained from 20 controls. VEMP responses were compared with both, clinical symptoms and results

Norihito Takeichi; Touru Sakamoto; Satoshi Fukuda; Yukio Inuyama

2001-01-01

146

Surgical management of brain-stem cavernomas  

Microsoft Academic Search

We present a series of seven patients who were operated on for symptomatic brain-stem cavernomas. The following approaches were used: medial suboccipital (N = 4), lateral suboccipital (N = 1), subtemporal-transtentorial (N = 1), and frontal transcortical-transventricular-subchorioidaltrans velum interpositum (N = 1). Intraoperative motor (N = 4) and somatosensory (N = 1) evoked potential monitoring revealed temporary changes in 3

Ulrich Pechstein; Josef Zentner; Dirk Van Roost; Johannes Schramm

1997-01-01

147

[Contact heat evoked potentials for the evaluation of pain pathways].  

PubMed

Pain evoked potentials offer a possibility for the evaluation of nociceptive pathways. Contact heat evoked potentials (CHEPS) represent a novel technique allowing to investigate peripheral pain pathways represented by small-diameter nerve fibers (A-delta and C fibers) and to study the spinothalamic tract. In contrast to more time-consuming methods such as quantitative sensory testing, CHEPS enables an objective investigation of pain pathways. This article reviews and discusses the technique, possible indications, and pitfalls in the context of clinical cases. PMID:18516578

Seifert, C L; Nitzsche, D; Valet, M; Tölle, T R; Sprenger, T

2008-08-01

148

Visual evoked potentials and the localization of visual pathway lesions  

Microsoft Academic Search

Summary  The site of a visual pathway lesion correlates with changes of the pattern reversal visual evoked potentials (VEPs).\\u000a \\u000a Optic nerve, optic chiasm and the retrochiasmal visual pathway lesions were explored by evoking visual potentials with a range\\u000a of stimulus sizes (full-field, half-field and central-field). Multichannel recording of VEPs was used.\\u000a \\u000a \\u000a \\u000a It was seen that certain forms of VEP changes were

J. Brecelj

1991-01-01

149

Auditory evoked potentials in multiple sclerosis: correlation with magnetic resonance imaging.  

PubMed

The present study addresses issues regarding the location of neural sources (i.e. generators) of human auditory evoked potentials (AEPs), and the pattern of neural conduction in the auditory pathway. AEPs were recorded from fifteen patients with multiple sclerosis (MS) and compared to normals. The recordings included auditory brainstem responses (ABRs), mid-latency responses (MLRs), and long-latency responses (LLRs). AEP latency abnormalities were related to the locus of demyelinating lesions, as determined by magnetic resonance imaging (MRI) scans. The data demonstrated several anatomical patterns relating abnormal ABR wave intervals and abnormal MRI signals. From these patterns specific loci for ABR neural sources in the brainstem might be postulated. In addition, the earlier the ABR waves, the more unilateral the abnormalities appeared, suggesting bilateral sources for later waves. The MLRs were highly correlated with ABR wave V and were associated with greater abnormality in MRI signals in midbrain and forebrain regions. In general, patients with abnormal LLRs also had widespread AEP and MRI abnormalities, supporting a multiple source approach for the N1 wave of the LLRs. The observation that LLRs were only abnormal in the presence of bilateral ABR abnormalities suggests a cross wiring which would serve as a compensatory mechanism for unilateral disturbances. The AEP data showed dissociation between early and late wave abnormalities, thus supporting parallel channels for neural conduction in the central auditory system. Such a model calls for some degree of independence of AEP generators along the auditory pathway. PMID:8910140

Hendler, T; Squires, N K; Moore, J K; Coyle, P K

1996-01-01

150

EVOKED POTENTIALS, PHYSIOLOGICAL METHODS WITH HUMAN APPLICATIONS  

EPA Science Inventory

A number of tests and test batteries have been developed and implemented for detecting potential neurotoxicity in humans. n some cases test results may suggest specific dysfunction. hile tests in laboratory animals are often used to project the potential for adverse health effect...

151

Evaluation of Evoked Potentials to Dyadic Tones after Cochlear Implantation  

ERIC Educational Resources Information Center

|Auditory evoked potentials are tools widely used to assess auditory cortex functions in clinical context. However, in cochlear implant users, electrophysiological measures are challenging due to implant-created artefacts in the EEG. Here, we used independent component analysis to reduce cochlear implant-related artefacts in event-related EEGs of…

Sandmann, Pascale; Eichele, Tom; Buechler, Michael; Debener, Stefan; Jancke, Lutz; Dillier, Norbert; Hugdahl, Kenneth; Meyer, Martin

2009-01-01

152

Cortical Auditory Evoked Potentials in Unsuccessful Cochlear Implant Users  

ERIC Educational Resources Information Center

|In some cochlear implant users, success is not achieved in spite of optimal clinical factors (including age at implantation, duration of rehabilitation and post-implant hearing level), which may be attributed to disorders at higher levels of the auditory pathway. We used cortical auditory evoked potentials to investigate the ability to perceive…

Munivrana, Boska; Mildner, Vesna

2013-01-01

153

Vestibular Evoked Myogenic Potentials in Patients with Idiopathic Bilateral Vestibulopathy  

Microsoft Academic Search

Idiopathic bilateral vestibulopathy (IBV) is an acquired bilateral peripheral vestibular disorder of unknown cause. Three patients diagnosed as IBV by neuro-otological examination were reported. They underwent vestibular evoked myogenic potential (VEMP) testing which reflects the functionality of the sacculo-collic pathway. As a result, 2 of the 3 patients showed bilateral absence of VEMPs and one showed unilateral absence. The VEMPs

Masaki Matsuzaki; Toshihisa Murofushi

2001-01-01

154

Age-Related Changes in Vestibular Evoked Myogenic Potentials  

Microsoft Academic Search

Vestibular evoked myogenic potentials (VEMP) in response to sound stimulation (500 Hz tone burst, 129 dB SPL) were studied in 1000 consecutive patients. VEMP from the ear with the larger amplitude were evaluated based on the assumption that the majority of the tested patients probably had normal vestibular function in that ear. Patients with known bilateral conductive hearing loss, with

Krister Brantberg; Kerstin Granath; Nadine Schart

2007-01-01

155

The variance modulation associated with the vestibular evoked myogenic potential  

Microsoft Academic Search

ObjectiveModel considerations suggest that the sound-induced inhibition underlying the vestibular evoked myogenic potential (VEMP) briefly reduces the variance of the electromyogram (EMG) from which the VEMP is derived. Although more difficult to investigate, this inhibitory modulation of the variance promises to be a specific measure of the inhibition, in that respect being superior to the VEMP itself. This study aimed

Bernd Lütkenhöner; Claudia Rudack; Türker Basel

2011-01-01

156

Vestibular evoked myogenic potentials (VEMP) can detect asymptomatic saccular hydrops  

Microsoft Academic Search

Objective: The objective of this study was to explore the useful of vestibular evoked myogenic potential (VEMP) testing for detecting endolymphatic hydrops, especially in the second ear of patients with unilateral Meniere disease (MD). Methods: This study was performed at a tertiary care academic medical center. Part I consisted of postmortem temporal bone specimens from the temporal bone collection of

Ming-Yee Lin; Ferdinand C. A. Timmer; Brad S. Oriel; Guangwei Zhou; John J. Guinan; Sharon G. Kujawa; Barbara S. Herrmann; Saumil N. Merchant; Steven D. Rauch

2006-01-01

157

Brain-Computer Interfaces Based on Visual Evoked Potentials  

Microsoft Academic Search

Recently, electroencephalogram (EEG)-based brain- computer interfaces (BCIs) have become a hot spot in the study of neural engineering, rehabilitation, and brain science. In this article, we review BCI systems based on visual evoked potentials (VEPs). Although the performance of this type of BCI has already been evaluated by many research groups through a variety of laboratory demonstrations, researchers are still

Yijun Wang; Xiaorong Gao; Bo Hong; Chuan Jia; Shangkai Gao

2008-01-01

158

Evoked Potentials in Faroese Children Prenatally Exposed to Methylmercury  

Microsoft Academic Search

A study of 7-year-old children from a fishing village on Madeira has suggested that latencies of evoked potentials may be delayed because of increased exposures to methylmercury during development. Data from a previously published prospective study in the Faroe Islands have therefore been reexamined. Because of changes in instrumentation, results obtained during the second year of examination were excluded. After

Katsuyuki Murata; Pal Weihe; Shunichi Araki; Esben Budtz-JØrgensen; Philippe Grandjean

1999-01-01

159

VALIDITY OF SPECTRAL ANALYSIS OF EVOKED POTENTIALS IN BRAIN RESEARCH  

Microsoft Academic Search

The averaged electronencephologram (EEG) response of the brain to an external stimulus (evoked potential, EP) is usually subjected to spec- tral analysis using the fast Fourier transform (FFT), especially to dis- cover the relation of cognitive ability to so-called brain dynamics. There is indeed a discrepancy between these two systems, because the brain is a highly complex nonlinear system, analyzed

ALEXANDER V. KRAMARENKO; UNER TAN

160

A Source Analysis of the Late Human Auditory Evoked Potentials  

Microsoft Academic Search

The intracerebral generators of the human auditory evoked potentials were estimated using dipole source analysis of 14-channel scalp recordings. The response to a 400-msec toneburst presented every 0.9 sec could be explained by three major dipole sources in each temporal lobe. The first was a vertically oriented dipole located on the supratemporal plane in or near the auditory koniocortex. This

Michael Scherg; Jiri Vajsar; Terence W. Picton

1989-01-01

161

Ontogeny of Flash-Evoked Potentials in Unanesthetized Rats.  

National Technical Information Service (NTIS)

The effects of age and stimulation frequency (0.2/sec, 1.0/sec, 2.0/sec, or 4.0/sec) on flash evoked potentials (FEPs) were investigated in awake, unsedated, unrestrained rats. Animals were tested daily from postnatal day (PND) 8 through PND 20, and every...

G. C. Rigdon R. S. Dyer

1987-01-01

162

COMPARABILITY OF RAT AND HUMAN VISUAL EVOKED POTENTIALS  

EPA Science Inventory

A series of experiments was conducted to assess the comparability of physiological processes in rat and human visual systems. n the first set of experiments, transient visual evoked potentials (VEPs) were elicited by the onset of sine-wave gratings of various spatial frequencies....

163

THE EFFECT OF EXPERIMENTAL CONCUSSION ON SOMATOSENSORY EVOKED POTENTIALS  

Microsoft Academic Search

Cortical somatosensory evoked potentials (SEPs) were recorded following experimental acceleration concussion in the rat. Immediately after head injury there was a general reduction in the amplitude of the SEP, and all its components were either temporarily abolished or increased in latency. The early components of the SEP recovered much more rapidly than did the amplitude and latencies of the later

NA Shaw; BR Cant

1984-01-01

164

Visual evoked potentials in children with neurofibromatosis type 1  

Microsoft Academic Search

The purposes of this investigation were to determine: (a) if visual evoked potential (VEP) abnormalities could be identified in children with neurofibromatosis type 1 (NF1) with no evidence of optic pathway or brain neoplasias on MRI; and (b) if VEP abnormalities could be explained by the presence of hyperintense T2-weighted foci on MRI testing, known as unidentified bright objects (UBOs).

Alessandro Iannaccone; Richard A. McCluney; Vickie R. Brewer; Peter H. Spiegel; June S. Taylor; Natalie C. Kerr; Enikö K. Pivnick

2002-01-01

165

Visual evoked potentials in children with occipital epilepsies  

Microsoft Academic Search

The objectives of this study are to see if any visual evoked potential (VEP) differences are present in two forms of occipital epilepsy, childhood epilepsy with occipital paroxysms (CEOP) and symptomatic occipital epilepsy (SOE) with respect to etiology, as CEOP is a benign age- and localization-related idiopathic epilepsy while SOE is a symptomatic form. Nineteen patients with CEOP and 13

Ahmet Gokcay; Ne?e Celeb?soy; Figen Gokcay; Özgül Ekmekc?; Ayfer Ulku

2003-01-01

166

Visual evoked potentials in infants exposed to methadone in utero  

Microsoft Academic Search

We investigated the effects of maternal drug misuse on neonatal visual evoked potentials (VEPs). Flash VEPs were recorded within 4 days of birth from 21 term infants of mothers misusing drugs and prescribed substitute methadone and 20 controls. Waveforms were classified as typical, atypical, immature or non-detectable, and amplitude and latencies were measured. VEPs from drug-exposed infants were less likely

L. McGlone; H. Mactier; M. S. Bradnam; R. Boulton; W. Borland; M. Hepburn; Daphne L. McCulloch

2008-01-01

167

Visual evoked potential measures of interhemispheric transfer time in humans  

Microsoft Academic Search

Four experiments testing fight-handed adult males examined interhemispheric transfer time (IHTT) estimation with visual evoked potentials (EPs) elicited in response to hemiretinal presentations of checkerboard-flash stimuli. Experiment 1 was a study of the relation between reaction time (RT) and EP measures of IHTT. EP measures provided more valid estimates than RT measures because more subjects showed IHTT in the direction

Clifford D. Saron; Richard J. Davidson

1989-01-01

168

Evaluation of Evoked Potentials to Dyadic Tones after Cochlear Implantation  

ERIC Educational Resources Information Center

Auditory evoked potentials are tools widely used to assess auditory cortex functions in clinical context. However, in cochlear implant users, electrophysiological measures are challenging due to implant-created artefacts in the EEG. Here, we used independent component analysis to reduce cochlear implant-related artefacts in event-related EEGs of…

Sandmann, Pascale; Eichele, Tom; Buechler, Michael; Debener, Stefan; Jancke, Lutz; Dillier, Norbert; Hugdahl, Kenneth; Meyer, Martin

2009-01-01

169

Comparability of Rat and Human Visual-Evoked Potentials.  

National Technical Information Service (NTIS)

A series of experiments was conducted to assess the comparability of physiological processes in rat and human visual systems. In the first set of experiments, transient visual evoked potentials (VEPs) were elicited by the onset of sine-wave gratings of va...

H. K. Hudnell W. K. Boyes

1991-01-01

170

Hearing in time: evoked potential studies of temporal processing.  

PubMed

This article reviews the temporal aspects of human hearing as measured using the auditory evoked potentials. Interaural timing cues are essential to the detection and localization of sound sources. The temporal envelope of a sound--how it changes in amplitude over time--is crucially important for speech perception. Time is taken to integrate, identify, and dissolve auditory streams. These temporal aspects of human hearing can be examined using the auditory evoked potentials, which measure the millisecond-by-millisecond activity of populations of neurons as they form an auditory percept. Important measurements are the time taken to localize sounds on the basis of their interaural time differences as measured by the cortical N1 wave, the contribution of the vocal cord frequency and phonemic frequency to the perception of speech sounds as indicated by the envelope-following responses, the temporal integration of sound as assessed using the steady state responses, and the duration of auditory memory as shown in the refractory periods of the slow auditory evoked potentials. Disorders of temporal processing are a characteristic feature of auditory neuropathy, a significant component of the hearing problems that occur in the elderly, and a possible etiological factor in developmental dyslexia and central auditory processing disorders. Auditory evoked potentials may help in the diagnosis and monitoring of these disorders. PMID:24005840

Picton, Terence

171

Cortically evoked potentials in the human subthalamic nucleus.  

PubMed

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) alleviates motor symptoms in Parkinson's disease (PD) patients. However, in a substantial number of patients the beneficial effects of STN DBS are overshadowed by psychiatric side effects. We hypothesize that stimulation of the STN motor area will provide the optimal effect on the motor symptoms without inducing these side effects, and expect that motor cortex stimulation (MCS) evokes a spatially specific response within the STN, which identifies the STN motor area. We previously showed that MCS evokes responses in the unit activity specifically within certain areas of the STN. Unit activity is generally considered a measure of the output activity. To gain more insight into the neuronal input into the STN, we describe the results of cortically evoked subthalamic local field potentials (LFPs). We show that the cortically evoked LFPs follow a certain temporal and spatial pattern. The significant peaks of the evoked LFPs coincide with the timing of some of the inhibitions and excitations present in the unit responses. The spatial resolution of responses measured in the LFP to MCS is not high enough to identify the STN motor region. However, we believe that optimizing targeting techniques and the development of novel DBS electrodes will improve STN DBS therapy for PD patients. PMID:23384566

Zwartjes, Daphne G M; Janssen, Marcus L F; Heida, Tjitske; Van Kranen-Mastenbroek, Vivianne; Bour, Lo J; Temel, Yasin; Visser-Vandewalle, Veerle; Veltink, Peter H

2013-02-04

172

Magnetic motor evoked potentials in ponies.  

PubMed

Magnetic stimulation of motor pathways was used to effect motor unit action potential recordings from forelimb and hindlimb muscles in unanesthetized ponies. Motor pathway conduction velocities to the forelimb and hindlimb were determined to be 53.8 +/- 9.6 m/s-1 and 63.4 +/- 8.3 m/s-1, respectively. This noninvasive technique will enable more precise evaluation of motor deficits in clinical patients than is possible with the neurological examination. PMID:8884720

Mayhew, I G; Washbourne, J R

173

Recording of electrically evoked auditory brainstem responses (E-ABR) with an integrated stimulus generator in Matlab  

Microsoft Academic Search

Electrical auditory brainstem responses (E-ABRs) of subjects with cochlear implants are used for monitoring the physiologic responses of early signal processing of the auditory system. Additionally, E-ABR measurements allow the diagnosis of retro-cochlear diseases. Therefore, E-ABR should be available in every cochlear implant center as a diagnostic tool. In this paper, we introduce a low-cost setup designed to perform an

Andreas Bahmer; Otto Peter; Uwe Baumann

2008-01-01

174

Commentary: somatosensory evoked potentials and magnetic fields.  

PubMed

Evidence is offered for the requirement of more careful comparisons between the new event related magnetic fields of the brain (ERMFb) and their conventional counterparts the event related brain potentials (ERBP), in the somato-sensory (SEP) and auditory (AEP) modalities at least, because the existing ERBP literature contains a wealth of well-documented data on these crucial issues: (1) Contralateral and ipsilateral SEP; (2) the relevance of "background" intrinsic periodicity; and (3) the relevance of stimulus parameters, receptive fields, and subjective perceptual status to variations in the waveforms. The importance of the new 2nd derivative magnetic gradiometry for better spatiotemporal resolution of sources and for functional understanding of cerebral electrophysiology cannot be overestimated. So it may be equally important to ensure that existing, historical data from conventional scalp-conductance, systematically recorded and analyzed during the past twenty years, are not ignored at the inception of essential comparisons using complementary electromagnetic techniques. PMID:6840984

Stowell, H

1983-01-01

175

An analytical model of the vestibular evoked myogenic potential  

Microsoft Academic Search

The vestibular evoked myogenic potential (VEMP) can be modeled (scaling factors aside) as a convolution of the motor unit action potential (MUAP) of a representative motor unit, h(t), with the temporal modulation of the MUAP rate of all contributing motor units, r(t). Accordingly, the variance modulation associated with the VEMP can be modeled as a convolution of r(t) with the

Bernd Lütkenhöner; Türker Basel

2011-01-01

176

Effect of Endothelin on Somatosensory Evoked Potentials in Rats  

Microsoft Academic Search

The effects of endothelin 1 (ET-1; 300 pmol\\/rat intracarotid) on somatosensory evoked potential were investigated in rats. ET-1 led to an amplitude reduction, peak latency prolongations and waveform disturbances. There was a large interindividual variability. The late cortical components were more affected than the earlier potentials at a thalamic or cortical level. ET-1-induced SEP changes developed quickly after the drug

A. Todorova; M. Boyagieva; T. Yosifov

1992-01-01

177

The neonatal development of the light flash visual evoked potential  

Microsoft Academic Search

Aims. To follow visual development longitudinally in the normal neonate using the flash visual evoked potential (VEP) and to find\\u000a indications for a relationship between potential development and visual development. Methods. Twenty healthy infants, born at term, were included in the study. Flash and patterned flash VEPs were used. The first VEP\\u000a was recorded the day of birth or just

Maria Kræmer; Maths Abrahamsson; Anders Sjöström

1999-01-01

178

Emotional modulation of pain-related evoked potentials?  

PubMed Central

To investigate whether cortical processing of trigeminal nociception is modulated by emotion, the N2 and P2 components of the pain-related evoked potential (PREP) were recorded in response to noxious stimulation of the supraorbital nerve while participants viewed neutral, pleasant and unpleasant pictures. The nerve was stimulated at 125% of pain threshold via a nociceptive-specific concentric electrode to selectively activate A-delta pain fibres. The N2 and P2 pain-related evoked potentials were similarly influenced by emotional priming: the amplitude of both potentials decreased monotonically from viewing neutral to pleasant to unpleasant pictures. These findings show that cortical processing of trigeminal nociception is modulated by emotion. We explain our findings in terms of the effects of picture viewing on attention.

Ring, Christopher; Kavussanu, Maria; Willoughby, Adrian R.

2013-01-01

179

Comparison of visual and auditory evoked cortical potentials in migraine patients between attacks  

Microsoft Academic Search

Objective: As both habituation of pattern reversal visual evoked potentials (PR-VEP) (Schoenen J, Wang W, Albert A, Delwaide PJ. Potentiation instead of habituation characterizes visual evoked potentials in migraine patients between attacks. Eur J Neurol 1995;2:115–122) and intensity dependence of auditory evoked cortical potentials (IDAP) (Wang W, Timsit-Berthier M, Schoenen J. Intensity dependence of auditory evoked potentials in migraine: an

J. Áfra; A. Proietti Cecchini; P. S. Sándor; J. Schoenen

2000-01-01

180

Nociceptive evoked potentials revisited in the frequency domain.  

PubMed

Human somatosensory evoked potentials (SEP), especially those evoked by electrical stimulation of toothpulp and teeth or by laser thermal stimulation of skin, have attracted biomedical attention since 1975 as possible indicators of the quantity of acute pain being perceived by the subject. The dental variety has been claimed as an "objective correlate of acute laboratory pain." But investigators of SEP for mechanical, electrical, and thermal stimulation of skin and mucocutaneous junctions have provided data which seriously question the meaning of that claim. Most recently dental SEP workers have rediscovered some well-known ambiguities in their own data, all of which refer only to time-domain or transient characteristics of event related brain potentials (ERBP). Perhaps we should reconsider an older approach to understanding ERBP, using concurrent analysis of their transient temporal and steady-state frequency characteristics. PMID:6469467

Stowell, H

1984-08-01

181

Vestibular evoked myogenic potentials in multiple sclerosis patients  

Microsoft Academic Search

Objectives: Vestibular evoked myogenic potentials (VEMPs) are saccular responses to loud acoustic stimuli and are recordable from the sterno-cleido-mastoid muscle ipsilaterally to the stimulated ear. This study aimed to investigate VEMPs in patients suffering from multiple sclerosis (MS), and to compare these findings with both clinical and instrumental data.Methods: We recorded VEMPs from 70 MS patients, whose clinical data were

Maurizio Versino; Silvia Colnaghi; Roberto Callieco; Roberto Bergamaschi; Alfredo Romani; Vittorio Cosi

2002-01-01

182

Development of Vestibular Evoked Myogenic Potentials in Preterm Neonates  

Microsoft Academic Search

Our recent study successfully recorded vestibular evoked myogenic potential (VEMP) responses in full-term newborns. However, when VEMP responses are elicited in preterm neonates remains unclear. This study employed the VEMP test in 27 low-risk preterm and 25 healthy full-term neonates without sedation to investigate the development of VEMP response after birth. Fourteen (26%) of 54 ears in preterm neonates exhibited

Shou-Jen Wang; Chun-Nan Chen; Wu-Shiun Hsieh; Yi-Ho Young

2008-01-01

183

Vestibular evoked myogenic potentials in Behcet’s disease  

Microsoft Academic Search

The aim of this study was to investigate vestibular evoked myogenic potentials (VEMPs) and their clinical significance in\\u000a Behcet’s disease. Twenty-six patients with Behcet’s disease and 25 healthy volunteers were evaluated for pure tone audiometry,\\u000a caloric response, and VEMPs. Sensorineural hearing loss was found in 53.8% of patients with Behcet’s disease, which was significantly\\u000a higher than controls. Four patients had

Seyra Erbek; Selim S. Erbek; Sema Yilmaz; Eftal Yucel; Levent N. Ozluoglu

2008-01-01

184

Vestibular Evoked Myogenic Potentials in Ipsilateral Delayed Endolymphatic Hydrops  

Microsoft Academic Search

We recorded vestibular evoked myogenic potentials (VEMPs) in 12 patients diagnosed as having ipsilateral delayed endolymphatic hydrops (DEH). Seventy-five percent (9\\/12) of the patients showed decreased or absent VEMPs in the affected ears. Almost all patients had normal VEMPs in the unaffected ears. In addition, in 4 patients, VEMPs were recorded before and 3 h after oral glycerol administration (1.3

Masafumi Ohki; Masaki Matsuzaki; Keiko Sugasawa; Toshihisa Murofushi

2002-01-01

185

Vestibular-evoked myogenic potentials in vestibular migraine  

Microsoft Academic Search

Sound-induced vestibular-evoked myogenic potentials (VEMPs) can be used to investigate saccular function, measured from the\\u000a tonically contracted sternocleidomastoid muscles (SCM) in response to loud sound stimuli. The aim of the present study was\\u000a to assess VEMPs in patients with vestibular migraine and to determine whether saccular function is affected by the disease.\\u000a Furthermore, tests such as tilts of subjective visual

Bernhard Baier; N. Stieber; M. Dieterich

2009-01-01

186

Asymmetric vestibular evoked myogenic potentials in unilateral Menière patients  

Microsoft Academic Search

Vestibular evoked myogenic potentials (VEMPs) were measured in 22 unilateral Menière patients with monaural and binaural stimulation\\u000a with 250 and 500 Hz tone bursts. For all measurement situations significantly lower VEMP amplitudes were on average measured\\u000a at the affected side compared to the unaffected side. Unilateral Menière patients have, in contrast to normal subjects, asymmetric\\u000a VEMPs, indicating a permanently affected vestibular

C. M. Kingma; H. P. Wit

2011-01-01

187

Age differences in visual evoked potential estimates on interhemishperic transfer  

Microsoft Academic Search

Twenty-six younger (ages 18-36 years) and 19 older (ages 60-88 years) healthy right-handed men and women were tested for interhemispheric transfer by using visual evoked potentials to laterally presented checkerboards. Interhemispheric transfer time (IHTT) was estimated by subtracting latencies for both P100 and N160 peaks of the waveform contralateral to the stimulus from the waveform ipsilateral to the stimulus for

Matthew J. Hoptman; Richard J. Davidson; Adalsteinn Gudmundsson; Ronald T. Schreiber; William B. Ershler

1996-01-01

188

Studies of human visual pathophysiology with visual evoked potentials  

Microsoft Academic Search

Visual evoked potentials (VEPs) offer reproducible and quantitative data on the function of the visual pathways and the visual cortex. Pattern reversal VEPs to full-field stimulation are best suited to evaluate anterior visual pathways while hemi-field stimulation is most effective in the assessment of post-chiasmal function. However, visual information is processed simultaneously via multiple parallel channels and each channel constitutes

Shozo Tobimatsu; Gastone G. Celesia

2006-01-01

189

The adaptive chirplet transform and visual evoked potentials  

Microsoft Academic Search

We propose a new approach based upon the adaptive chirplet transform (ACT) to characterize the time-dependent behavior of the visual evoked potential (VEP) from its initial transient portion (tVEP) to the steady-state portion (ssVEP). This approach employs a matching pursuit (MP) algorithm to estimate the chirplets and then a maximum-likelihood estimation (MLE) algorithm to refine the results. The ACT decomposes

Jie Cui; Willy Wong

2006-01-01

190

Cerebral evoked potentials after endorectal mechanical stimulation in humans.  

PubMed

Although numerous clinical studies have proved that impaired rectal sensation is a major factor in fecal continence dysfunctions, objective studies in this field are still lacking. To provide information on normal rectal afferents, a study of cerebral potentials evoked by mechanical stimulation of the rectal wall was carried out in 10 healthy volunteers (5 male, 5 female; age, 33-52 yr). The stimulating device consisted of a rectal balloon rhythmically inflated and deflated by means of an animal breathing ventilator. Recordings were obtained 2 cm behind the vertex (C'z, International system 10-20). The responses were averaged from 300 to 800 sweeps. The average was triggered either on inflation ("on effect") or on deflation ("off effect"). Inflation volume and pressure were adjusted to induce a clear but not painful pulsing sensation. Reproducible responses were recorded by both on and off effects. The evoked potentials were polyphasic with a succession of positive and negative waves (peak latencies between 78 and 310 ms). The shape of the response (morphology, latency, and amplitude) was perfectly reproducible in the same subject. With regard to intrasubject reproducibility, variability was displayed: only the early waves (latency less than 100 ms) were perfectly reproducible; late waves exhibited variable latency and morphology. The present findings are the first demonstration of the possibility of recording an evoked potential on the scalp after a mechanical stimulation of the rectum. PMID:3354668

Collet, L; Meunier, P; Duclaux, R; Chery-Croze, S; Falipou, P

1988-04-01

191

EEG and the variance of motor evoked potential amplitude.  

PubMed

The motor threshold is an important parameter in selecting the treatment intensity of patients undergoing transcranial magnetic stimulation. The large variance in magnitude of motor evoked responses has forced clinicians to perform many trials and average the results to find a repeatable value for motor threshold. Our objective is to investigate the source of the variance in amplitude. Four clinically healthy adult males participated in an EEG and EMG during transcranial magnetic stimulation of the left motor cortex, 100% motor threshold, 0.1 Hz. Per our hypothesis, a significant negative correlation of .22 was found between the amplitude of the motor evoked potential and the power in the high alpha frequency band during the pre-stimulus period (p < .001). In addition, a significant positive correlation of .17 was found between the motor evoked potential (MEP) amplitude and the gamma band (p < .001). The strongest correlation of .27 (p < .001) was found between the MEP amplitude and the ratio of the power in the low gamma to high alpha band. We conclude that the gamma to alpha power ratio may be a useful indicator of cortical excitability. PMID:16929713

Zarkowski, P; Shin, C J; Dang, T; Russo, J; Avery, D

2006-07-01

192

Recording of electrically evoked auditory brainstem responses (E-ABR) with an integrated stimulus generator in Matlab.  

PubMed

Electrical auditory brainstem responses (E-ABRs) of subjects with cochlear implants are used for monitoring the physiologic responses of early signal processing of the auditory system. Additionally, E-ABR measurements allow the diagnosis of retro-cochlear diseases. Therefore, E-ABR should be available in every cochlear implant center as a diagnostic tool. In this paper, we introduce a low-cost setup designed to perform an E-ABR as well as a conventional ABR for research purposes. The distributable form was developed with Matlab and the Matlab Compiler (The Mathworks Inc.). For the ABR, only a PC with a soundcard, conventional system headphones, and an EEG pre-amplifier are necessary; for E-ABR, in addition, an interface to the cochlea implant is required. For our purposes, we implemented an interface for the Combi 40+/Pulsar implant (MED-EL, Innsbruck). PMID:18621081

Bahmer, Andreas; Peter, Otto; Baumann, Uwe

2008-06-24

193

Habituation and sensitization in rat auditory evoked potentials: a single-trial analysis with wavelet denoising  

Microsoft Academic Search

Abstract In this work, systematic changes of single-trial auditory evoked potentials elicited in rats were studied. Single-trial evoked potentials were obtained with the help of wavelet denoising, a very recently proposed method that has already been,shown,to be useful in the analysis of scalp human,evoked,potentials. For the evoked,components,in the Ž. 1324-ms range i.e. P13, N18, P20 and N24 , it was

R. Quian Quiroga

194

Habituation and sensitization in rat auditory evoked potentials: a single-trial analysis with wavelet denoising  

Microsoft Academic Search

In this work, systematic changes of single-trial auditory evoked potentials elicited in rats were studied. Single-trial evoked potentials were obtained with the help of wavelet denoising, a very recently proposed method that has already been shown to be useful in the analysis of scalp human evoked potentials. For the evoked components in the 13–24-ms range (i.e. P13, N18, P20 and

R. Quian Quirogaa

2002-01-01

195

Intraoperative monitoring of motor function by magnetic motor evoked potentials.  

PubMed

Under etomidate anesthesia, motor evoked potentials produced by magnetic stimulation were successfully recorded from 10 thenar muscles and 10 anterior tibial muscles of eight patients who had undergone surgery on the medulla oblongata and the cervical and thoracic spinal cords. Recordings taken before placing the neural tissue at risk were assessed for variability in amplitude and latency. The lower limit in amplitude was approximately one-third (25-43%) of the baseline. The latencies were more difficult to monitor than were the amplitudes. The latency variations were 2.56 +/- 0.50 milliseconds for the hand and 6.84 +/- 1.37 milliseconds for the leg. During surgery, the unilateral recordings of two patients were transiently lost but partially recovered after a pause in the operation. No obvious postoperative weaknesses in the corresponding limbs occurred. One patient, who showed a permanent loss of unilateral recording, had transient monoplegia with a complete recovery. None of the remaining five patients who had amplitudes larger than one-third of the baseline at the end of the operation had additional motor deficits. Our conclusions are that under etomidate anesthesia, the magnetic motor evoked potentials can be convenient and reliable monitors of motor function, that changes in the amplitude may be superior to those in the latency for intraoperative warning, that the criterion for potential neural damage under magnetic motor evoked potential monitoring might be an amplitude reduction of two-thirds of the control value, and that the magnetic stimulation seems to be more sensitive than the electrical stimulation in the monitoring of motor function and also allows more time and opportunities for the motor function to recover. PMID:7753349

Lee, W Y; Hou, W Y; Yang, L H; Lin, S M

1995-03-01

196

CHLORDIMEFORM PRODUCES CONTRAST-DEPENDENT CHANGES IN VISUAL EVOKED POTENTIALS OF HOODED RATS  

EPA Science Inventory

Acute exposure to the insecticide/acaricide chlordimeform (CDM) produces large, selective and transient changes in visual evoked potentials of rats. Experiments were conducted investigating the influence of physical characteristics of the evoking stimuli on the CDM effect. Adult ...

197

Lateral dominance and visual evoked potentials in albinos.  

PubMed

Lateral preferences for the use of eye, hand, and foot were assessed in 17 male and female albino subjects, aged 15 to 52 yr. Visual evoked potential (VEP) recordings suggested that optic fibres were abnormally decussated in these subjects, as others have shown. Fewer albino subjects showed the lateral preference for the use of hand/eye and foot/eye similar to that of normals. It is postulated that the abnormal decussation of optic fibres may underlie the reduced preference for the use of the same hand and eye, and foot and eye, in albinos. PMID:3725523

Murdoch, B D; Reef, H E

1986-06-01

198

Estimation of evoked potentials using total least squares prony technique.  

PubMed

The authors investigate the applicability of Prony modelling to the estimation of evoked potentials. Four types of total least squares (TLS) model are considered and their optimal parameters are defined based on ten visual averaged EPs. Simulations with various signal and noise characteristics show that the TLS-Prony estimation is superior to averaging for two of the models, namely the unconstrained and the stable models. Application of the TLS-Prony estimator as a post-processor to moderate averaging allows a reduction in the number of responses averaged, or equivalently of recording time, by a factor of two. PMID:10367435

Akkin, T; Saliu, S

1998-09-01

199

Cortical processing of musical consonance: an evoked potential study.  

PubMed

Cortical processes underlying perception of musical consonance were investigated by long-latency auditory evoked potentials (EPs). Subjects listened to a random sequence of dyadic pure tones paired at various pitch intervals (1, 4, 6, 7, or 9 semitones). Amplitudes of P2 and N2 components of auditory EPs were significantly modulated by pitch interval of the dyads, being most negative for 1 semitone (minor second) and least negative or most positive for 7 semitones (perfect fifth). The results indicate that neural processing of consonance depend not only on peripheral mechanisms in the inner ear but also on higher associative processing of pitch relationships in the cerebral cortex. PMID:14663180

Itoh, Kosuke; Suwazono, Shugo; Nakada, Tsutomu

2003-12-19

200

A novel shape analysis technique for somatosensory evoked potentials.  

PubMed

Somatosensory evoked potentials (SEP) have been shown to be an important electrophysiological measure to assess the integrity of the spinal cord. However the peaks in the SEP waveform are often undetectable due to low signal-to-noise (SNR) ratio. Sometimes they also become indistinct during injury when the SEP flattens. Hence time-domain analysis methods are often subject to errors, and need human-expert intervention. In this paper, we propose a new technique for analyzing the shape of the evoked potentials, in which slope information is obtained for the entire signal in specific time bins. Apart from solving the problems associated with present methods, this technique has an added advantage of analyzing the SEP signal as a whole rather than simply a few peaks. The efficacy of this technique was investigated on SEP signals recorded from 12 rats before and after contusion spinal cord injury at thoracic vertebra T8. The statistical analysis results revealed significant effect of injury to hindlimbs, whereas almost none to forelimbs. Thus, the results show high potential of this technique to differentiate between normal and injured spinal cord. PMID:19163762

Agrawal, Gracee; Sherman, David; Thakor, Nitish; All, Angelo

2008-01-01

201

Properties of rectified averaging of an evoked-type signal: theory and application to the vestibular-evoked myogenic potential  

Microsoft Academic Search

The properties of rectified averages were investigated using the VEMP (vestibular-evoked myogenic potential) as an example\\u000a of an evoked-type response. Recordings were made of surface EMG from the sternocleidomastoid (SCM) muscles of six volunteers,\\u000a unstimulated, at different levels of tonic activation and then in response to clicks of different intensities. The stochastic\\u000a properties of the surface EMG recorded were shown

J. G. Colebatch

2009-01-01

202

A wireless system for monitoring transcranial motor evoked potentials.  

PubMed

Intraoperative neurophysiological monitoring (IONM) is commonly used as an attempt to minimize neurological morbidity from operative manipulations. The goal of IONM is to identify changes in the central and peripheral nervous system function prior to irreversible damage. Intraoperative monitoring also has been effective in localizing anatomical structures, including peripheral nerves and sensorimotor cortex, which helps guide the surgeon during dissection. As part of IONM, transcranial motor evoked potentials (TcMEPs), and somatosensory evoked potentials (SSEPs) are routinely monitored. However, current wired systems are cumbersome as the wires contribute to the crowded conditions in the operating room and in doing so not only it limits the maneuverability of the surgeon and assistants, but also places certain demand in the total anesthesia required during surgery, due to setup preoperative time needed for proper electrode placement, due to the number and length of the wires, and critical identification of the lead wires needed for stimulation and recording. To address these limitations, we have developed a wireless TcMEP IONM system as a first step toward a multimodality IONM system. Bench-top and animal experiments in rodents demonstrated that the wireless method reproduced with high fidelity, and even increased the frequency bandwidth of the TcMEP signals, compared to wired systems. This wireless system will reduce the preoperative time required for IONM setup, add convenience for surgical staff, and reduce wire-related risks for patients during the operation. PMID:20824343

Farajidavar, Aydin; Seifert, Jennifer L; Bell, Jennifer E S; Seo, Young-Sik; Delgado, Mauricio R; Sparagana, Steven; Romero, Mario I; Chiao, J-C

2010-09-08

203

Dichloroacetylene: effects on the rat trigeminal nerve somatosensory evoked potential.  

PubMed

Humans overexposed to trichloroethylene (TCE), under specific conditions, were reported to develop trigeminal nerve dysfunction. A degradation byproduct dichloroacetylene (DCA), however, has been suggested as the probable neurotoxicant rather than TCE. Studies in mice, rats, and rabbits support the hypothesis of DCA-induced trigeminal neurotoxicity. This study, therefore, was conducted to characterize DCA-induced trigeminal nerve dysfunction in rats using the electrodiagnostic procedure trigeminal nerve-stimulated somatosensory evoked potential (TSEP). A group of six rats was exposed once to DCA (approximately 300 ppm) or room air for 2.25 h and a separate group of six rats was not exposed and served as controls. Trigeminal nerve somatosensory evoked potentials (TSEPs) were collected before exposure and 2, 4, and 7 days postexposure. Because DCA was manufactured from TCE with acetylene added as a stabilizer, another group of rats was exposed to TCE and acetylene without generation of DCA. TSEPs from DCA-exposed rats were smaller and slower compared to their baseline recordings and to the concurrent negative controls. TSEPs from the controls and the TCE/acetylene-exposed rats were unchanged. Neuropathology did not reveal treatment-related lesions. It was concluded that the rat is mildly to markedly susceptible to DCA-induced trigeminal nerve dysfunction as assessed by TSEP, but that the kidney was the likely target organ based on gross observations and the DCA literature. PMID:9088008

Albee, R R; Nitschke, K D; Mattsson, J L; Stebbins, K E

204

Visual evoked potential monitoring of optic nerve function during surgery.  

PubMed Central

A study was made with intra-operative flash--visual evoked potentials (VEP) monitored using a fibre-optic/contact lens photo stimulator in 57 patients undergoing intra-orbital surgical procedures with potential risk to the optic nerve. The VEPs recorded under enflurane and nitrous oxide anaesthesia did not differ significantly in latency or amplitude from the pre-operative recordings. Transient abolition of the VEP was seen under many circumstances and did not correlate with the outcome of surgery, but absence of a previously normal VEP for more than four minutes during surgical manipulation within the orbit did show a correlation with post operative impairment of vision. The technique provides early warning to the surgeon of threats to the integrity of the optic nerve.

Harding, G F; Bland, J D; Smith, V H

1990-01-01

205

Automatic denoising of single-trial evoked potentials.  

PubMed

We present an automatic denoising method based on the wavelet transform to obtain single trial evoked potentials. The method is based on the inter- and intra-scale variability of the wavelet coefficients and their deviations from baseline values. The performance of the method is tested with simulated event related potentials (ERPs) and with real visual and auditory ERPs. For the simulated data the presented method gives a significant improvement in the observation of single trial ERPs as well as in the estimation of their amplitudes and latencies, in comparison with a standard denoising technique (Donoho's thresholding) and in comparison with the noisy single trials. For the real data, the proposed method largely filters the spontaneous EEG activity, thus helping the identification of single trial visual and auditory ERPs. The proposed method provides a simple, automatic and fast tool that allows the study of single trial responses and their correlations with behavior. PMID:23142653

Ahmadi, Maryam; Quian Quiroga, Rodrigo

2012-11-01

206

Effect of endothelin on somatosensory evoked potentials in rats.  

PubMed

The effects of endothelin 1 (ET-1; 300 pmol/rat intracarotid) on somatosensory evoked potential were investigated in rats. ET-1 led to an amplitude reduction, peak latency prolongations and waveform disturbances. There was a large interindividual variability. The late cortical components were more affected than the earlier potentials at a thalamic or cortical level. ET-1-induced SEP changes developed quickly after the drug injection and persisted for at least 30 min. It is assumed that the observed effects probably reflect the occurrence of a progressively developing ischemia subsequent to ET-1 administration. Moreover, the pattern of ET-1-induced changes suggests a greater sensitivity of the synaptic transmission to the ischemic influence than the axonal conduction. PMID:1475035

Todorova, A; Boyagieva, M; Yosifov, T

1992-01-01

207

Conscious Wireless Electroretinogram and Visual Evoked Potentials in Rats  

PubMed Central

The electroretinogram (ERG, retina) and visual evoked potential (VEP, brain) are widely used in vivo tools assaying the integrity of the visual pathway. Current recordings in preclinical models are conducted under anesthesia, which alters neural physiology and contaminates responses. We describe a conscious wireless ERG and VEP recording platform in rats. Using a novel surgical technique to chronically implant electrodes subconjunctivally on the eye and epidurally over the visual cortex, we are able to record stable and repeatable conscious ERG and VEP signals over at least 1 month. We show that the use of anaesthetics, necessary for conventional ERG and VEP measurements, alters electrophysiology recordings. Conscious visual electrophysiology improves the viability of longitudinal studies by eliminating complications associated with repeated anaesthesia. It will also enable uncontaminated assessment of drug effects, allowing the eye to be used as an effective biomarker of the central nervous system.

He, Zheng; Dang, Trung M.; Vingrys, Algis J.; Fish, Rebecca L.; Gurrell, Rachel; Brain, Phil; Bui, Bang V.

2013-01-01

208

Conscious wireless electroretinogram and visual evoked potentials in rats.  

PubMed

The electroretinogram (ERG, retina) and visual evoked potential (VEP, brain) are widely used in vivo tools assaying the integrity of the visual pathway. Current recordings in preclinical models are conducted under anesthesia, which alters neural physiology and contaminates responses. We describe a conscious wireless ERG and VEP recording platform in rats. Using a novel surgical technique to chronically implant electrodes subconjunctivally on the eye and epidurally over the visual cortex, we are able to record stable and repeatable conscious ERG and VEP signals over at least 1 month. We show that the use of anaesthetics, necessary for conventional ERG and VEP measurements, alters electrophysiology recordings. Conscious visual electrophysiology improves the viability of longitudinal studies by eliminating complications associated with repeated anaesthesia. It will also enable uncontaminated assessment of drug effects, allowing the eye to be used as an effective biomarker of the central nervous system. PMID:24069276

Charng, Jason; Nguyen, Christine T; He, Zheng; Dang, Trung M; Vingrys, Algis J; Fish, Rebecca L; Gurrell, Rachel; Brain, Phil; Bui, Bang V

2013-09-12

209

Mid-latency auditory evoked potentials in 2 meditative states.  

PubMed

Mid-latency auditory evoked potentials (MLAEPs) were assessed in 60 participants during 4 mental states described in traditional yoga texts. These 4 mental states are random thinking, nonmeditative-focused thinking, meditative focusing, and meditation. Assessments were made before (5 minutes), during (20 minutes), and after (5 minutes) each of the 4 states, on 4 separate days. There were prolonged latencies of 2 MLAEPs components, the Na and Pa waves during meditation (P < .05, post hoc analyses following analysis of variance [ANOVA]), suggesting that auditory information transmission at the level of the medial geniculate and primary auditory cortex (ie, the neural generators corresponding to the Na and Pa waves) was delayed. Hence, meditation influenced MLAEPs, while meditative focusing did not. PMID:22715488

Telles, Shirley; Raghavendra, Bhat Ramachandra; Naveen, Kalkuni Visweswaraiah; Manjunath, Nandi Krishnamurthy; Subramanya, Pailoor

2012-04-16

210

Multifocal visual evoked potentials in amblyopia due to anisometropia  

PubMed Central

Purpose: To investigate multifocal visual evoked potentials (mfVEP) of the amblyopic and fellow eye in amblyopia due to anisometropia. Methods: We recorded mfVEP in both eyes of 15 anisometropic amblyopic patients and 15 normal control subjects. The responses from the central 7.0° arc of the visual field were measured, and changes in latency and amplitude were compared between the amblyopic, fellow, and normal control eyes. Results: There was a significant difference in the latency and amplitude of mfVEP between the amblyopic and fellow eyes. The responses in the central region of the visual field (rings 1 and 2) had a longer latency and smaller amplitude in the amblyopic eye. In contrast, there was no difference in mfVEP latency or amplitude between the fellow eye and normal control eyes. Conclusion: These results suggest that mfVEP may be used as an alternative objective method for diagnosis and monitoring of anisometropic amblyopia.

Moschos, MM; Margetis, I; Tsapakis, S; Panagakis, G; Chatzistephanou, IK; Iliakis, E

2010-01-01

211

Sensory physiology assessed by evoked potentials in survivors of poliomyelitis.  

PubMed

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. PMID:18816600

Prokhorenko, Olga A; Vasconcelos, Olavo M; Lupu, Vitalie D; Campbell, William W; Jabbari, Bahman

2008-10-01

212

Multifocal visual-evoked potential in unilateral compressive optic neuropathy  

PubMed Central

Aim To evaluate the effects of unilateral compressive optic neuropathy on amplitude and latency of multifocal visual evoked potentials (mfVEPs). Methods Static automated perimetry and mfVEP recordings were obtained from six patients with presumed meningiomas affecting one optic nerve. Monocular and interocular amplitude and latency analyses were performed and compared with normal control subjects. Results The change in the mfVEP amplitude agreed with visual field findings with regard to topography and severity of deviation from normal. The delay in recordable responses from affected eyes ranged from 7.6 to 20.7?ms (interocular analysis) and 7.9 to 13.9?ms (monocular analysis). Conclusions Compressive optic neuropathy decreases the amplitude and increases the latency of the mfVEP. The changes in latency were similar to those seen in optic neuritis but larger than those in ischaemic optic neuropathy and glaucoma.

Semela, Linda; Yang, E Bo; Hedges, Thomas R; Vuong, Laurel; Odel, Jeffery G; Hood, Donald C

2007-01-01

213

Effects of lead and mercury intoxications on evoked potentials  

SciTech Connect

Pattern reversal, brain stem auditory and somatosensory evoked potentials (PREPs, BAEPs, SEPs) have been recorded on 13 patients occupationally exposed to inorganic lead compounds, in 9 patients occupationally or accidentally exposed to inorganic mercury compounds and in 26 chronic alcoholics. The results were compared to those of a normal control group. Peripheral conduction velocities were decreased in lead exposed workers and in alcoholics, but not modified in the mercury exposed patients. In the three exposed groups, an amplitude increase (PREPs and upper limb SEP cortical components), more important in the mercury group and an increase of central conduction time in case of lower limb stimulation, could be interpreted as early signs of nervous cortical impairment.

Lille, F.; Hazemann, P.; Garnier, R.; Dally, S.

1988-01-01

214

Cervical Vestibular-Evoked Myogenic Potentials: Norms and Protocols  

PubMed Central

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.

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

2012-01-01

215

A Study of Evoked Potentials From Ear-EEG.  

PubMed

A method for brain monitoring based on measuring the electroencephalogram (EEG) from electrodes placed in-the-ear (ear-EEG) was recently proposed. The objective of this study is to further characterize the ear-EEG and perform a rigorous comparison against conventional on-scalp EEG. This is achieved for both auditory and visual evoked responses, over steady-state and transient paradigms, and across a population of subjects. The respective steady-state responses are evaluated in terms of signal-to-noise ratio and statistical significance, while the qualitative analysis of the transient responses is performed by considering grand averaged event-related potential (ERP) waveforms. The outcomes of this study demonstrate conclusively that the ear-EEG signals, in terms of the signal-to-noise ratio, are on par with conventional EEG recorded from electrodes placed over the temporal region. PMID:23722447

Kidmose, Preben; Looney, David; Ungstrup, Michael; Rank, Mike Lind; Mandic, Danilo P

2013-05-29

216

Contact heat evoked potentials using simultaneous EEG and fMRI and their correlation with evoked pain  

PubMed Central

Background The Contact Heat Evoked Potential Stimulator (CHEPS) utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm/heat thresholds of receptors expressed by A? and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials using electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has not previously been reported with CHEPS. Developing simultaneous EEG and fMRI with CHEPS is highly desirable, as it provides an opportunity to exploit the high temporal resolution of EEG and the high spatial resolution of fMRI to study the reaction of the human brain to thermal and nociceptive stimuli. Methods In this study we have recorded evoked potentials stimulated by 51°C contact heat pulses from CHEPS using EEG, under normal conditions (baseline), and during continuous and simultaneous acquisition of fMRI images in ten healthy volunteers, during two sessions. The pain evoked by CHEPS was recorded on a Visual Analogue Scale (VAS). Results Analysis of EEG data revealed that the latencies and amplitudes of evoked potentials recorded during continuous fMRI did not differ significantly from baseline recordings. fMRI results were consistent with previous thermal pain studies, and showed Blood Oxygen Level Dependent (BOLD) changes in the insula, post-central gyrus, supplementary motor area (SMA), middle cingulate cortex and pre-central gyrus. There was a significant positive correlation between the evoked potential amplitude (EEG) and the psychophysical perception of pain on the VAS. Conclusion The results of this study demonstrate the feasibility of recording contact heat evoked potentials with EEG during continuous and simultaneous fMRI. The combined use of the two methods can lead to identification of distinct patterns of brain activity indicative of pain and pro-nociceptive sensitisation in healthy subjects and chronic pain patients. Further studies are required for the technique to progress as a useful tool in clinical trials of novel analgesics.

Roberts, Katherine; Papadaki, Anastasia; Goncalves, Carla; Tighe, Mary; Atherton, Duncan; Shenoy, Ravikiran; McRobbie, Donald; Anand, Praveen

2008-01-01

217

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

PubMed Central

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.

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

2013-01-01

218

Nasopharyngeal recordings of somatosensory evoked potentials document the medullary origin of the N18 far-field.  

PubMed

Because the nasopharyngeal electrode provides non-invasive access to the ventral brain-stem at the medullo-pontine level we used it for recording somatosensory evoked potentials (SEPs) to median nerve stimulation (non-cephalic reference). After the P9 and P11 far-fields, the nasopharyngeal SEPs disclosed a negative-going component which was interpreted as the near-field equivalent of the P14 scalp far-field generated in the caudal part of the medial lemniscus. Nasopharyngeal SEPs also revealed a large N18 with voltage and features strikingly similar to those of the scalp-recorded N18 far-field. These results suggest that N18 is generated in the medulla and not more rostrally in the brain-stem. The use of a nasopharyngeal electrode as reference for topographic brain mapping is discussed. The paper documents the feasibility and relevance of nasopharyngeal recordings for non-invasive analysis of short-latency SEPs. PMID:1720725

Tomberg, C; Desmedt, J E; Ozaki, I; Noël, P

219

Spinal Cord-Evoked Potentials and Muscle Responses Evoked by Transcranial Magnetic Stimulation in 10 Awake Human Subjects  

Microsoft Academic Search

Transcranial magnetic stimulation (TCMS) causes leg muscle contractions, but the neural structures in the brain that are activated by TCMS and their relationship to these leg muscle responses are not clearly understood. To elucidate this, we concomitantly recorded leg muscle responses and thoracic spinal cord-evoked potentials (SCEPs) after TCMS for the first time in 10 awake, neurologically intact human subjects.

David A. Houlden; Michael L. Schwartz; Charles H. Tator; Peter Ashby; William A. MacKay

1999-01-01

220

Modified sound-evoked brainstem potentials in Foxp2 mutant mice  

Microsoft Academic Search

Heterozygous mutations of the human FOXP2 gene cause a developmental disorder involving impaired learning and production of fluent spoken language. Previous investigations of its aetiology have focused on disturbed function of neural circuits involved in motor control. However, Foxp2 expression has been found in the cochlea and auditory brain centers and deficits in auditory processing could contribute to difficulties in

Simone Kurt; Matthias Groszer; Simon E. Fisher; Günter Ehret

2009-01-01

221

AMPD2 regulates GTP synthesis and is mutated in a potentially treatable neurodegenerative brainstem disorder.  

PubMed

Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acid synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenosine and guanine nucleotides. We describe a distinct early-onset neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH) due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a potentially treatable early-onset neurodegenerative disease. PMID:23911318

Akizu, Naiara; Cantagrel, Vincent; Schroth, Jana; Cai, Na; Vaux, Keith; McCloskey, Douglas; Naviaux, Robert K; Van Vleet, Jeremy; Fenstermaker, Ali G; Silhavy, Jennifer L; Scheliga, Judith S; Toyama, Keiko; Morisaki, Hiroko; Sonmez, Fatma M; Celep, Figen; Oraby, Azza; Zaki, Maha S; Al-Baradie, Raidah; Faqeih, Eissa A; Saleh, Mohammed A M; Spencer, Emily; Rosti, Rasim Ozgur; Scott, Eric; Nickerson, Elizabeth; Gabriel, Stacey; Morisaki, Takayuki; Holmes, Edward W; Gleeson, Joseph G

2013-08-01

222

[Value of the studies of multimodal evoked potentials for evaluation of neurotoxic effects of combined exposure to lead, copper and zinc].  

PubMed

Central nervous system dysfunction was studied in workers with occupational exposure to Pb+Cu+Zn by measuring somatosensory evoked potentials of short and long latency, visual evoked potentials and brain-stem evoked auditory potentials. The tests were done in 40 workers with a history of exposure from 6 to 19 (mean 14.3) years in a copper foundry. Pb poisoning was not diagnosed in them, but 18 workers had some abnormalities of heme synthesis. Pb concentration in blood was from 11.4 to 62.8 (mean 35.7) mcg% in the whole group. Pb concentration in air in the foundry exceeded 1.1-175 times the MAC value, the concentration of CU exceeded it 7.25 times. Zn concentration was half the MAC value. No significant abnormalities were found in the parameters of multimodal evoked potentials. The obtained data suggest a protective effect of copper and zinc on heme , Pb blood level and conduction velocity of somatosensory, visual and auditory impulses in workers exposed to high Pb air concentration. PMID:1811176

Langauer-Lewowicka, H; Kazibutowska, Z

223

[Loss of brain stem auditory evoked potential waves I and II during controlled hypotension].  

PubMed

For surgical removal of a malignant choroid melanoma, it is necessary to reduce systolic blood pressure to around 50-60 mmHg in order to prevent choroidal haemorrhages. However, blood pressure reduction is associated with the risk of cerebral ischaemia. We report a patient with a malignant choroid melanoma in whom waves I and II of the brainstem auditory evoked potentials (BAEP) disappeared during surgery under controlled arterial hypotension and hypothermia (31.1 degrees C). The waves could be recorded again immediately after the mean arterial pressure was increased from 48 to 77 mmHg. The oesophageal temperature had dropped by 0.3 degrees C at this time. The 2-channel electroencephalogram (EEG) showed no irregularities during this time period. A bilateral, reversible, apparently blood-pressure-dependent loss of waves I and II during arterial hypotension despite a normal EEG has to our knowledge not been previously described in the literature. The isolated loss of waves I and II with maintenance of waves III, IV, and V is unusual. The literature contains reports of acoustic neurinoma patients in whom only wave V could be recorded. This is regarded as an indication of continued impulse conduction despite the loss of waves I to IV. Others have observed a patient with temporary and reversible loss of BAEP wave I due to vasospasm of the internal auditory artery that apparently occurred during or shortly after manipulation of the internal auditory meatus. Assuming anatomic peculiarities in the blood supply to the generators of the BAEP waves, a stenosis of the basilar artery could be considered as the cause of the bilateral reversible loss of waves I and II. Another potential source could be induced hypothermia, but this does not seem very likely because the patient's temperature was 0.3 degrees C lower at the return of the waves than at their loss. PMID:8678270

Papadopoulos, G; Lang, M; Link, J; Schäfer, M; Schaffartzik, W; Eyrich, K; Bornfeld, N; Foerster, M H

1995-11-01

224

[Highpass filtering of auditory evoked brain stem potentials (author's transl)].  

PubMed

Twenty ears of normal-hearing subjects are investigated as to the influence of highpass filtering on latency, amplitude, and shape of auditory evoked brain stem potentials. For this purpose, three different Bessel-filters (steepness 24 dB/octave) with lower cut-off frequencies at 100, 200, and 300 Hz (3-dB down points) and an upper cut-off frequency at 3 kHz are used. Spectral composition of brain stem potentials is analyzed by digital filtering based on Fast Fourier Transformation. Results show decreasing latency and amplitude of the negative wave between Jewett V and VI with increasing lower cut-off frequency. With higher edge frequencies we find attenuation of wave V relative to wave IV amplitudes. For that reason we must assume that an essential part of brain stem activity is located below 300 Hz. In our experience moderate highpass filtering seems to be useful in neurological cases to eliminate low frequency components of the signal. In that way potentials I -- V are easy to be identified and interpeak latencies can be determined without any problems. For objective threshold determination, however, brain stem potentials should be derived preferably with broadband filter settings to improve correlation of tone audiometric hearing loss (at about 3 kHz) and brain stem response threshold. A filter set with different lower cut-off frequencies has proved to be really useful in routine work. However, it must by taken into account that highpass filtering means an alteration of the original response in any case. PMID:7295174

Kiessling, J; Althaus, V

1981-01-01

225

DETECTION OF EVOKED POTENTIAL EMBEDDED IN EEG WITH TIME-VARYING AUTOCORRELATION FUNCTION  

Microsoft Academic Search

Statistical Objective Response Detection (ORD) Techniques applied to Evoked Potentials usually depend on the effective Number of Degrees of Freedom (NDOF) of spontaneous EEG. This work proposes a method to estimate the NDOF for the probability distribution of EPD (Evoked Potential Detector) under the null hypothesis of no-response, based on the EEG autocorrelation function (ACF), and assesses its performance applied

Maurício Cagy; Antonio Fernando; C. Infantosi; Eduardo J. B. Zaeyen

226

Visual and motor evoked potentials in the course of multiple sclerosis  

Microsoft Academic Search

Summary While evoked potentials are sensitive tools for diagnosing multiple sclerosis, little is known about their prognostic value and their role in determining the course of the disease. To validate the visual and motor evoked potentials (VEP and MEP) as measures for the course of multiple sclerosis, we examined prospectively 30 patients with relapsing-remitting or secondary progressive multiple sclerosis. The

P. Fuhr; A. Borggrefe-Chappuis; C. Schindler; L. Kappos

2001-01-01

227

Spinothalamic tract conduction velocity estimated using contact heat evoked potentials: What needs to be considered  

Microsoft Academic Search

ObjectiveLaser-evoked potentials have been shown to be clinically useful for the electrophysiological assessment of nociceptive pathways. Contact heat evoked potentials (CHEP) are less established but might be advantageous for clinical purposes. This study aimed at determining the conduction velocity (CV) of central pain (spinothalamic tract, STT) pathways using contact heat stimulation in order to replicate previous findings using laser stimulation.

Susanne Wydenkeller; Regula Wirz; Pascal Halder

2008-01-01

228

On the relationship between nociceptive evoked potentials and intraepidermal nerve fiber density in painful sensory polyneuropathies  

Microsoft Academic Search

This study analyzed the relationship between the density of intraepidermal nerve fibers (IENF) and the characteristics of either nociceptive laser-evoked potentials (LEPs) or contact heat-evoked potentials (CHEPs) in patients with painful sensory polyneuropathy with the aim to determine which parameters of LEPs and CHEPs more reliably reflect IENF loss. A total of 96 patients and 35 healthy volunteers took part

Jordi Casanova-Molla; Josep Maria Grau-Junyent; Merche Morales; Josep Valls-Solé

2011-01-01

229

Unusual postnatal development of visually evoked potentials in four brain areas of white zebra finches  

Microsoft Academic Search

The central visual system of white zebra finches is physiologically different from normally coloured (wild type) birds, although the eye pigmentation and the retinofugal projection appear to be normal. Ipsilaterally evoked potentials in the white birds are enhanced in comparison to wild type birds, whereas in albino mammals the ipsilateral component of visually evoked potentials is reduced. The present study

Manfred Bredenkötter; Hans-Joachim Bischof

2003-01-01

230

Amblyopia in unilateral congenital ptosis: early detection by sweep visual evoked potential  

Microsoft Academic Search

•Background: Fixation preference assessment is a clinical tool widely used to determine amblyopia in young infants and children. It is our clinical experience that this tool underestimates amblyopia. The purpose of this study was to compare the results of sweep visual evoked potentials to fixation preference assessment in cases of unilateral ptosis. • Methods: Sweep visual evoked potentials were performed

Gerhard W. Cibis; Kathleen M. Fitzgerald

1995-01-01

231

Relationship between Visual Evoked Potentials and Subjective Differences between Emotional Expressions in “Face Diagrams”  

Microsoft Academic Search

The relationship between visual evoked potentials resulting from substitution of one image of a human “face diagram” for another and assessment of perceived differences between the emotional expressions of these faces were studied. Emotions were altered by changing the curvature of the mouth and\\/or the slope of the brows. Unlike the traditional approach, in which visual evoked potentials are recorded

Ch. A. Izmailov; S. G. Korshunova; E. N. Sokolov

2001-01-01

232

Monocular contribution to the peak time of the binocular pattern visual evoked potential  

Microsoft Academic Search

The contribution of each monocular pathway to the timing of the binocular pattern visual evoked potential was assessed in situations where a significant interocular timing discrepancy was observed. Monocular and binocular pattern visual evoked potentials to 0.5° checks were recorded from normal subjects, normal subjects in whom one eye was blurred, patients with monocular amblyopia, and patients with resolved unilateral

Michelle McKerral; Pierre Lachapelle; François Tremblay; Robert C. Polomeno; Marie-Sylvie Roy; Raquel Beneish; Franco Leporé

1995-01-01

233

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

Microsoft Academic Search

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

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

1985-01-01

234

Development of a visual stimulation system and its application to visual evoked potentials  

Microsoft Academic Search

We report our development of a multi-purpose visual stimulation system for the generation of visual evoked potentials. The system was designed to provide a comprehensive selection of visual stimuli and enable the experimenter to vary a number of critical parameters surrounding the stimulus. This provides experimental control over the evoked potential visual stimulus, allowing for more accurate reproductions of experiments

G. Krumdick; B. He

1998-01-01

235

Effect of stimulus check size on multifocal visual evoked potentials.  

PubMed

In this study we examined the effects of varying stimulus check size on multifocal visual evoked potential (VEP). We also evaluated the currently used cortical scaling of stimulus segments. The ObjectiVision multifocal objective perimeter stimulates the eye with random check patterns at 56 cortically scaled segments within the visual field extending to a radius of 26 degrees. All cortically scaled segments have equal number of checks, which gradually increase in size from the center to the periphery, proportional to the size of the segment. Stimuli with 9, 16, 25, 36 and 49 checks/segment were tested on 10 eyes belonging to 10 normal subjects. The check size varied inversely with number of checks per segment. VEP was recorded using bipolar occipital cross electrodes (7 min/eye), the amplitude and latency of responses obtained were compared with the check size at different eccentricities. Our findings suggest that the existing setting with 16 checks/segment subtending 26' to 140' from center to periphery, is the most effective amongst all the check sizes. Decreasing the check size prolongs the latency in the central field only. Cortical scaling of segments generates responses of the same order of magnitude throughout the field, but could be improved slightly to enhance the signal from the outer two rings. PMID:12678283

Balachandran, Chandra; Klistorner, Alexander I; Graham, Stuart L

2003-03-01

236

Effect of pupil size on multifocal pattern visual evoked potentials.  

PubMed

The purpose of this study was to investigate the influence of pupil diameter on the amplitude and latency of multifocal visual evoked potentials (mfVEP). The multifocal objective perimeter (Accumap; Objectivision) was used to stimulate the visual field at 56 sites extending to 32 degrees using a pseudo-random pattern stimulus. The mfVEP were recorded using bipolar occipital electrodes, 7 min/eye. Ten normal subjects were recruited from the community and one eye was randomly selected for testing. The mfVEP were recorded at four different pupil diameters (2 mm, 4 mm, 6 mm, 8 mm), obtained by applying tropicamide (0.5%) or pilocarpine (2%) in different dilutions. Appropriate refractive correction was provided to overcome cycloplegia and achieve a visual acuity of 6/7.5 or better. Analysis revealed that at most pupil diameters the normalized full field amplitude did not show significant variation, except at the most miotic pupil diameter (2 mm), where the amplitude became reduced, based on 2-way anova and Tukey's T method. There was, however, significant correlation between latency and pupil area (correlation coefficient: upper field -0.63, lower field -0.76). The results suggest that even in the presence of mydriatics or miotics, the mfVEP test can be used to assess diseases that affect amplitude, provided near correction is used. The interpretation of latency, however, must be made with caution, as a borderline conduction defect with a dilated pupil may appear normal. PMID:12880463

Martins, Alessandra; Balachandran, Chandra; Klistorner, Alexander I; Graham, Stuart L; Billson, Francis A

2003-08-01

237

Vestibular evoked myogenic potentials in patients with BPPV  

PubMed Central

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.

Korres, Stavros; Gkoritsa, Eleni; Giannakakou-Razelou, Dimitra; Yiotakis, Ioannis; Riga, Maria; Nikolpoulos, Thomas P.

2011-01-01

238

Validation of a rational malingering test using evoked potentials.  

PubMed

Malingering is easy to define, difficult to detect, and very costly for any health care system. The structured interview of reported symptoms (SIRS) was constructed using rational strategies to detect malingering in patients endorsing psychotic symptoms. This study validated the SIRS using evoked potentials. Nineteen patients meeting DSM-IV criteria for schizophrenia and 15 healthy controls completed an oddball and paired click protocol. Severity of psychotic symptoms was documented using the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms. The patient group was divided by probability of malingering according to the SIRS. Patients with a high probability of malingering had significantly greater P3 amplitude (P = 0.006, t-test) and more P50 suppression (P = 0.044, t-test) than patients with a low probability of malingering. No significant difference in P3 amplitude or P50 suppression was found between the patients with a high probability of malingering and the healthy controls. This study provides empirical support for the validity of the SIRS with evidence that is independent of patient report. PMID:17912066

Zarkowski, Paul; Esparza, Brian; Russo, Joan

2007-10-01

239

Effects of blood glutamate scavenging on cortical evoked potentials.  

PubMed

It is well known that traumatic or ischemic brain injury is followed by acute excitotoxicity caused by the presence of abnormally high glutamate (Glu) in brain fluids. It has recently been demonstrated that excess Glu can be eliminated from brain into blood following the intravenous administration of oxaloacetate (OxAc), which, by scavenging blood Glu, induces an enhanced and neuroprotective brain-to-blood Glu efflux. In this study, we subjected rats to intravenous OxAc administration (i.v., 12.5, 25, and 50 mg/kg, respectively), and studied its effects on somatosensory evoked cortical potentials (EPs). Against our expectation, the amplitudes of EPs did not decrease but increased in a dose- and time-dependent manner after OxAc administration. Similar effects were observed when blood Glu scavenging was enhanced by combining OxAc (12.5 mg/kgbw) with recombinant glutamate-oxaloacetate transaminase (GOT, 0.14 nmol/100 g rat). On the basis of these results, we suggest that the changes of amplitudes of the EPs involve not only a glutamatergic but also the weakening of a GABAergic component. We cannot rule out the possibility that OxAc penetrates into the brain and improves mitochondrial functions. PMID:20607387

Nagy, Dávid; Knapp, Levente; Marosi, Máté; Farkas, Tamás; Kis, Zsolt; Vécsei, László; Teichberg, Vivian I; Toldi, József

2010-07-06

240

Electroretinogram and visual-evoked potential measurements in sheep.  

PubMed Central

Electroretinogram (ERG) and visual-evoked potential (VEP) recordings were taken from ten Suffolk-cross sheep. Stimuli for VEP were 1.5 flashes of white light/s; ERG stimuli were single flashes. The ERG measurements of the a and b wave latencies and a-to-b amplitude were measured between the lower eyelid and the vertex, with ground on the nuchal crest. The VEP after monocular stimulation were measured between the nuchal crest and the interorbital line, with ground on the vertex. Measurements consisted of the latencies to seven alternating positive and negative peaks P1, N1, P2, N2, P3, N3 and P4, and six amplitudes, P1-N1, N1-P2, P2-N2, N2-P3, P3-N3 and N3-P4. Average latencies for the a and b waves were 13.6 and 28.2 ms; the mean ab amplitude was 131.68 microV. Average latencies for the seven VEP peaks were 35.0, 43.1, 52.8, 64.1, 74.5, 90.4 and 112.2 ms. Mean amplitudes ranged from 3.90 to 8.29 microV.

Strain, G M; Claxton, M S; Prescott-Mathews, J S; LaPhand, D J

1991-01-01

241

Cortical auditory evoked potentials in unsuccessful cochlear implant users.  

PubMed

In some cochlear implant users, success is not achieved in spite of optimal clinical factors (including age at implantation, duration of rehabilitation and post-implant hearing level), which may be attributed to disorders at higher levels of the auditory pathway. We used cortical auditory evoked potentials to investigate the ability to perceive and discriminate auditory stimuli in 10 unsuccessful implant users aged 8-10 years (CI) and 10 healthy age-matched controls with normal hearing (NH). Pure tones (1 and 2 kHz) and double consonant-vowel syllables were applied. The stimuli were presented in an oddball paradigm that required the subjects to react consciously. The latencies and amplitudes of the P1, N1, P2, N2 and P3 waves were analyzed, in addition to reaction times and number of responses. Significant differences in the average response times and number of responses were observed between the CI and NH groups. The latencies also indicate that the CI group took longer to perceive and discriminate between tonal and speech auditory stimuli than the NH group. PMID:23621479

Munivrana, Boška; Mildner, Vesna

2013-04-26

242

Auditory Evoked Potential Variability in Healthy and Schizophrenia Subjects  

PubMed Central

Objectives To investigate if the reduced P50, N100 and P200 auditory evoked potential (EP) components and gating deficits seen in schizophrenia can be explained in terms of response incompleteness. Methods Twenty-five healthy and schizophrenia participants were studied using pairs of 1000 Hz tones (S1 and S2, 0.5 s apart) separated by 8.0 s. A correlation-based clustering method identified the responses containing P50, N100, and/or P200 related-activity. Results Schizophrenia participants produced fewer S1 and S2 responses containing all three EP components than healthy participants. Healthy participants, but not the patient population, produced fewer and smaller S2 than S1 responses containing all three EP components. However, the S2 responses following complete S1 responses were smaller than the complete S1 responses in both populations. Conclusions The gating deficits observed in schizophrenia are due to two mechanisms. First, the S1 response consistency is less in schizophrenia than in health. Second, the S2 responses are attenuated less in schizophrenia. Significance This research contributes to the understanding of response variability and sensory gating in health and schizophrenia. It also extends previous reports that fewer and smaller P300 components are produced in schizophrenia than in health to the mid-latency component range.

Jansen, Ben H.; Hu, Lingli; Boutros, Nash N.

2010-01-01

243

Grating-evoked cortical potentials and perceived contrast (A)  

NASA Astrophysics Data System (ADS)

Unlike subjective perception of contrast, steady-state evoked cortical potentials (VEP's) elicited with counterphased gratings may vary abruptly with changes in spatial frequency.(1) To avoid possible artifacts we developed a digital fast-sweep technique for investigating this discrepancy. In most of our 13 subjects, at high stimulus contrasts the dependency of VEP amplitude on spatial frequency had two pronounced peaks separated by a sharp notch at around 3 cycles per degree. With decreasing contrast these variations leveled out, and a unimodal response function was obtained at low contrast. A linear relationship between log contrast and VEP amplitude(2) was found for any given spatial frequency only in the low-contrast range. With increasing contrast the VEP amplitude saturated at a rate that depended clearly on spatial frequency, with a nonmonotonous dependency occurring at intermediate spatial frequencies. The latter phenomenon of oversaturation apparently gave rise to the above-mentioned bimodal response characteristic. Results of a careful analysis of VEP phase lags are added. (1) C. W. Tyler et al., Brain Res. 33, 535 (1978). (2) F. W. Campbell and L. Maffei, J. Physiol. 207, 635 (1970).

Strasburger, Hans; Scheidler, Wolfgang; Rentschler, Ingo

244

[Frontal evoked potentials and sensitivity to methylphenidate. Individual differences].  

PubMed

Auditory evoked potentials (AEPs) were recorded from 2 sites (Cz and Fz) on 17 subjects while awake. Five sound intensities were used (40-50-60-70-80 dB). Regression slopes relating AEP amplitude (N1-P2 component) to stimulus intensity were used to describe augmentation or reduction (A/R) of amplitude with increasing intensity. The individual differences thereby obtained have been related with the individual responsiveness to methylphenidate (MPD) measured by the modifications of polygraphic sleep parameters after absorption of this substance. The sleep parameters were recorded under 3 conditions: N1, night of habituation; N2, reference night (placebo); N3, night after 20 mg of methylphenidate (MPD); nights 2 and 3 consisted of a double blind cross-over. For the placebo condition, the lower the A/R slope while awake (and particularly the Fz slope), the higher the sleep efficiency, with scarcity of nocturnal awakening and precocity of the morning awakening. Individual differences concerning MPD responsiveness measured with sleep parameter modifications are significantly correlated with the frontal A/R slopes: the wakefulness effect of MPD increases as the frontal A/R slope weakens while a paradoxal drowsiness effect is observed at the other extreme (frontal augmenters). Moreover, sleep modifications due to the first night effect show similarities with those due to MPD and are correlated in the same way with frontal A/R slopes. PMID:6463312

Bruneau, N; Laffont, F; Roux, S; Autret, A; Cathala, H P

1984-06-01

245

Visual evoked potentials in rotogravure printers exposed to toluene.  

PubMed Central

Visual evoked potentials (VEPs) from stimulation by checkerboard pattern reversal were examined in 54 rotogravure printers exposed to toluene (all men, aged 22-64 years, duration of exposure 1-41 years). A control group consisted of 46 subjects (23 men and 23 women; aged 22-54 years). Compared with controls the exposed group showed more frequent responses with reduced reproducibility or absence of some waves, or both; the mean P1 wave latency was prolonged and mean amplitudes N1P1 and P1N2 were reduced. The VEPs were abnormal in 24% of workers. The frequency of abnormal VEPs correlated positively with the duration of exposure to toluene and also with the degree of alcohol drinking. No association was found between measurements of VEP and electroencephalogram (EEG) or electromyogram (EMG) examinations. A VEP measurement was made in 78% of the exposed workers two years after the first examination. No statistically significant difference between the two results was found. This suggests a marked stability of the observed VEP changes. These changes can be interpreted as a subclinical sign of dysfunction of the central nervous system (CNS) related to exposure to toluene and also to alcohol consumption.

Urban, P; Lukas, E

1990-01-01

246

Measuring action potential-evoked transmission at individual synaptic contacts  

NASA Astrophysics Data System (ADS)

In the neuronal culture experimental system, the total synaptic connection between two neurons can consist of large numbers of synaptic sites, each behaving probabilistically. Studies of synaptic function with paired recordings typically consider the summed response across all of these sites and from this infer the average response. Understanding of synaptic transmission and plasticity could be improved by examination of activity at as few synaptic sites as possible. To this end, we develop a system for recording responses from individual contacts. It relies on a precisely regulated pneumatic/hydrostatic pressure system to create a microenvironment within which individual synapses are active, and an acoustic signature method to monitor the stability of this microenvironment noninvasively. With this method we are able to record action potential-evoked postsynaptic currents consistent with individual quanta. The approach does not distort synaptic current waveforms and permits stable recording for several hours. The method is applied to address mechanisms of short-term plasticity, the variability of latency at individual synaptic sites and, in a preliminary experiment, the independence of nearby synapses on the same axon.

Nauen, David W.; Bi, Guo-Qiang

2012-06-01

247

Preliminary results of the relationship between the binaural interaction component of the electrically evoked auditory brainstem response and interaural pitch comparisons in bilateral cochlear implant recipients  

PubMed Central

Objectives The purpose of this study was to investigate the relationship between electrophysiologic measures of the binaural interaction component (BIC) of the electrically evoked auditory brainstem response (EABR) and psychophysical measures of interaural pitch comparisons in Nucleus bilateral cochlear implant users. Design Data were collected for ten postlingually deafened adult cochlear implant users. Each subject conducted an interaural pitch-comparison task using a biphasic pulse train with a pulse rate of 1000 pulses per second (pps) at high stimulation levels. Stimuli were presented in a two-interval, two-alternative forced-choice procedure with roving current variations. A subgroup of four subjects repeated the task at low stimulation levels. BICs were measured using loudness balanced, biphasic current pulses presented at a rate of 19.9 pps for each subject by pairing the electrode 12 (out of 22 intracochlear electrodes) in the right ear with each of 11 electrodes spaced across the electrode array in the left ear. The BIC was measured at high stimulation levels in ten subjects and at low stimulation levels in seven subjects. Because of differences in stimulation rate used in BIC measures and interaural pitch comparisons, the actual stimulation levels were different in these two measures. The relationship between BIC responses and results of interaural pitch comparisons was evaluated for each of the individual subjects as well as at the group level. Evaluation was carried out separately for results obtained at high and low stimulation levels. Results There was no significant correlation between results of BIC measures and interaural pitch comparisons on either the individual or group levels. Lower stimulation level did not improve the relationship between these two measures. Conclusions No significant correlations between psychophysical measures of interaural pitch comparisons and electrophysiologic measures of the BIC of the EABR were found. The lack of correlation may be attributed to methods used to quantify the data, small number of subjects retested at low stimulation levels, as well as central processing components involved in the interaural pitch-comparison task.

He, Shuman; Brown, Carolyn J.; Abbas, Paul J.

2011-01-01

248

Bickerstaff brainstem encephalitis. A grave non-demyelinating disease with benign prognosis.  

PubMed

We describe 6 patients with ophthalmoplegia, ataxia and normal or exaggerated deep tendon reflexes. All had been preceded by a febrile illness and had a full recovery without sequelae. The brainstem auditory evoked potentials showed a localised lesion in the upper brainstem while the pattern shift visual evoked potentials were normal and did not show any additional silent lesions. CSF IgG oligoclonal bands were not detected in any of the patients. MRI in 2 patients showed a confluent high intensity lesion in the upper mesencephalon and thalamus involving white and gray matter. Follow-up ranged from 6 to 24 months and showed no relapse. PMID:2351986

Yaqub, B A; al-Deeb, S M; Daif, A K; Sharif, H S; Shamena, A R; al-Jaberi, M; Obeid, T; Panayiotopoulos, C C

1990-04-01

249

[Present situation and development of ocular vestibular-evoked myogenic potential].  

PubMed

Myogenic potentials evoked by air conducted sound (ACS), bone conducted vibration (BCV) or galvanic pulses can be recorded with surface electrodes over contracted muscles. These myogenic potentials are of vestibular origin (utricle and saccule) and so these potentials are called vestibular evoked myogenic potentials (VEMPs). Since the vestibular system has projections to many muscle systems, there are many such VEMPs. In this review, we discuss the generated origin, response pathway, waveform characteristics and clinical application of ocular vestibular-evoked myogenic potential (oVEMP). PMID:23833997

Hu, Juan; Xu, Min; Zhang, Qing

2013-04-01

250

Galvanic ocular vestibular evoked myogenic potentials provide new insight into vestibulo-ocular reflexes and unilateral vestibular loss  

Microsoft Academic Search

ObjectiveSynchronous extraocular muscle activity can be recorded from around the eyes at the beginning of a vestibular-evoked eye movement (ocular vestibular evoked myogenic potentials, OVEMPs). As galvanic vestibular stimulation (GVS) evokes the vestibulo-ocular reflex, we wished to investigate GVS-evoked OVEMPs.

Sally M. Rosengren; Peter Jombik; G. Michael Halmagyi; James G. Colebatch

2009-01-01

251

Trigeminal small-fibre function assessed with contact heat evoked potentials in humans  

Microsoft Academic Search

Contact heat stimuli have been reported to excite mechano-thermal nociceptors and to evoke brain potentials (CHEPs) from the limbs. We investigated whether contact heat evokes reproducible CHEPs from the trigeminal territory and may prove a reliable diagnostic tool in facial neuropathic pain. We applied contact heat stimuli to the perioral and supraorbital regions; CHEPs were recorded from the vertex in

A. Truini; F. Galeotti; E. Pennisi; F. Casa; A. Biasiotta; G. Cruccu

2007-01-01

252

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

ERIC Educational Resources Information Center

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…

Izawa, Shuji; Mizutani, Tohru

253

Predicting perception in noise using cortical auditory evoked potentials.  

PubMed

Speech perception in background noise is a common challenge across individuals and health conditions (e.g., hearing impairment, aging, etc.). Both behavioral and physiological measures have been used to understand the important factors that contribute to perception-in-noise abilities. The addition of a physiological measure provides additional information about signal-in-noise encoding in the auditory system and may be useful in clarifying some of the variability in perception-in-noise abilities across individuals. Fifteen young normal-hearing individuals were tested using both electrophysiology and behavioral methods as a means to determine (1) the effects of signal-to-noise ratio (SNR) and signal level and (2) how well cortical auditory evoked potentials (CAEPs) can predict perception in noise. Three correlation/regression approaches were used to determine how well CAEPs predicted behavior. Main effects of SNR were found for both electrophysiology and speech perception measures, while signal level effects were found generally only for speech testing. These results demonstrate that when signals are presented in noise, sensitivity to SNR cues obscures any encoding of signal level cues. Electrophysiology and behavioral measures were strongly correlated. The best physiological predictors (e.g., latency, amplitude, and area of CAEP waves) of behavior (SNR at which 50 % of the sentence is understood) were N1 latency and N1 amplitude measures. In addition, behavior was best predicted by the 70-dB signal/5-dB SNR CAEP condition. It will be important in future studies to determine the relationship of electrophysiology and behavior in populations who experience difficulty understanding speech in noise such as those with hearing impairment or age-related deficits. PMID:24030818

Billings, Curtis J; McMillan, Garnett P; Penman, Tina M; Gille, Sun Mi

2013-09-13

254

[Trigeminal somatosensory evoked potentials: I. Recording technic and normal responses].  

PubMed

The general wave form and time course of somatosensory evoked potentials (SEP) to the stimulation of upper and lower extremities has been well known in recent years. However, only a little information has been published so far on SEP to the trigeminal nerve stimulation (TSEP), and at present there is not always common methodology available in clinical practice. These may be due to the technical problems from the close proximity of stimulating and recording electrodes. The purpose of this report is to attempt to solve some of the difficulties of the procedure, as well as to show the morphology and time course of TSEP in a group of normal healthy subjects. Twenty healthy volunteers were investigated. Their age ranged from 22 to 61 years old (mean 29.3). Clip shaped silver-balled stimulating electrodes with 2 mm contact surface and interelectrode distance of 10 mm were applied to the inner surface of the lips. They were held in place without any support, thus minimizing muscle activity of the subject. Each half of the upper and lower lip was then stimulated in turn by an electrical rectangular pulse of 3 or 4 times sensory threshold (usually 1.5-2.0 mA) and 0.2 msec duration, at a rate of 2.3 per second. TSEP was recorded contralaterally from C'5 or C'6 (midpoint between Cz and external auditory porus). Fz was used as a reference. Four hundred responses were averaged by a Nicolet Pathfinder II, which also generated stimulation pulses. Stimulus polarity was reversed after each 100 stimuli to eliminate stimulus artifact. Analysis time was set to 50 msec.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3828144

Seki, Y; Aiba, T; Shirai, Y; Ishiyama, Y

1987-02-01

255

Paying attention to orthography: a visual evoked potential study.  

PubMed

In adult readers, letters, and words are rapidly identified within visual networks to allow for efficient reading abilities. Neuroimaging studies of orthography have mostly used words and letter strings that recruit many hierarchical levels in reading. Understanding how single letters are processed could provide further insight into orthographic processing. The present study investigated orthographic processing using single letters and pseudoletters when adults were encouraged to pay attention to or away from orthographic features. We measured evoked potentials (EPs) to single letters and pseudoletters from adults while they performed an orthographic-discrimination task (letters vs. pseudoletters), a color-discrimination task (red vs. blue), and a target-detection task (respond to #1 and #2). Larger and later peaking N1 responses (~170 ms) and larger P2 responses (~250 ms) occurred to pseudoletters as compared to letters. This reflected greater visual processing for pseudoletters. Dipole analyses localized this effect to bilateral fusiform and inferior temporal cortices. Moreover, this letter-pseudoletter difference was not modulated by task and thus indicates that directing attention to or away from orthographic features did not affect early visual processing of single letters or pseudoletters within extrastriate regions. Paying attention to orthography or color as compared to disregarding the stimuli (target-detection task) elicited selection negativities at about 175 ms, which were followed by a classical N2-P3 complex. This indicated that the tasks sufficiently drew participant's attention to and away from the stimuli. Together these findings revealed that visual processing of single letters and pseudoletters, in adults, appeared to be sensory-contingent and independent of paying attention to stimulus features (e.g., orthography or color). PMID:23734115

Herdman, Anthony T; Takai, Osamu

2013-05-21

256

Magnetic motor evoked potentials during methohexital anesthesia in the dog.  

PubMed

Magnetic motor evoked potentials (MMEPs) were recorded from the right cranial tibial muscle after magnetic stimulation of the left motor cortex in six dogs sedated with oxymorphone. Anesthesia was induced with an intravenous bolus of 5.5 mg/kg of methohexital and maintained with a methohexital infusion. The dogs inspired 100% oxygen during anesthesia. Blood pressure, heart rate, respiratory rate, esophageal temperature, and end-tidal carbon dioxide tension were recorded. The depth of anesthesia was increased until the amplitude of the MMEP was less than 5% of the control value, and the dogs were then allowed to recover. Every 5 minutes during anesthesia, a blood sample was taken for methohexital assay and at the same time, four replicate MMEPs were recorded. Plasma methohexital levels were significantly (P < 0.05) correlated with heart rate (p = 0.38) and end-tidal carbon dioxide tension (p = 0.49) and negatively correlated with respiratory rate (p = 0.74). There was no significant correlation between blood pressure and methohexital levels. The dogs regained consciousness at a plasma methohexital level of 10.4 +/- 3.8 micrograms/ml (mean +/- SD). The amplitude of the MMEP decreased significantly with increasing methohexital levels. In four dogs, the relationship was reasonably linear. The MMEP disappeared at a plasma methohexital level of 23 +/- 6.6 micrograms/ml. The latency of onset of the MMEP increased significantly from its control value of 14.7 +/- 1.0 ms to 17.5 +/- 1.3 ms at the highest methohexital levels at which MMEPs were recordable. This study demonstrated that MMEPs can be reliably recorded under methohexital anesthesia. PMID:8190225

Young SS; discussion 495; Boermans, H J; Sylvestre, A M

1994-03-01

257

Paying attention to orthography: a visual evoked potential study  

PubMed Central

In adult readers, letters, and words are rapidly identified within visual networks to allow for efficient reading abilities. Neuroimaging studies of orthography have mostly used words and letter strings that recruit many hierarchical levels in reading. Understanding how single letters are processed could provide further insight into orthographic processing. The present study investigated orthographic processing using single letters and pseudoletters when adults were encouraged to pay attention to or away from orthographic features. We measured evoked potentials (EPs) to single letters and pseudoletters from adults while they performed an orthographic-discrimination task (letters vs. pseudoletters), a color-discrimination task (red vs. blue), and a target-detection task (respond to #1 and #2). Larger and later peaking N1 responses (~170 ms) and larger P2 responses (~250 ms) occurred to pseudoletters as compared to letters. This reflected greater visual processing for pseudoletters. Dipole analyses localized this effect to bilateral fusiform and inferior temporal cortices. Moreover, this letter-pseudoletter difference was not modulated by task and thus indicates that directing attention to or away from orthographic features did not affect early visual processing of single letters or pseudoletters within extrastriate regions. Paying attention to orthography or color as compared to disregarding the stimuli (target-detection task) elicited selection negativities at about 175 ms, which were followed by a classical N2-P3 complex. This indicated that the tasks sufficiently drew participant's attention to and away from the stimuli. Together these findings revealed that visual processing of single letters and pseudoletters, in adults, appeared to be sensory-contingent and independent of paying attention to stimulus features (e.g., orthography or color).

Herdman, Anthony T.; Takai, Osamu

2013-01-01

258

Cerebral monitoring in the operating room and the intensive care unit - an introductory for the clinician and a guide for the novice wanting to open a window to the brain. Part II: Sensory-evoked potentials (SSEP, AEP, VEP).  

PubMed

An evoked potential differs from the EEG mainly in two ways: 1. The EEG is a random, continuous signal, which arises from the ongoing activity of the outer layers of the cortex. An evoked potential is the brain's response to a repetitive stimulus along a specific nerve pathway. 2.EEG signals range from 10-200 milliVolt (mV). Evoked potentials are smaller in amplitude (1-5-20 microVolt requiring precise electrode positioning and special techniques (signal averaging) to extract the specific response from the underlying EEG "noise". The technique of signal averaging, as originally described by Dawson in 1954 [69J, has been further developed in computer processing. The technique is now used by applying a stimulus repeatedly--preferably at randomized intervals--and to record the evoked response over the corresponding area of the brain, averaging out mathematically the change over the number of stimuli. Rationale for the use of EPs in the OR and the ICU. Evoked potentials (EPs) serve the following major purposes: 1. Monitoring of the functional integrity of neural structures that may be at risk during, for instance, ECC (extracorporeal circulation) or endarterectomy indicating cerebral hypoxia. 2. Monitoring of the effects of anesthetic agents and other centrally active drugs, which, besides the cortex, affect deeper neuronal structures. 3. Orthopedic cases where the spinal cord is at risk such as Harrington rod insertion and removal. 4. Clamping of the abdominal aortic artery during aneurysmectomy resulting in a potential damage of the lower parts of the spinal cord. 5. Clipping of an intracerebral aneurysm, which may be impeding blood flow to vital cerebral textures. 6. An indicator of cerebral hypoxia when the blood pressure is deliberately lowered. 7. Operation on peripheral nerves and nerve roots to identify early trauma. 8. Monitoring the cerebral function during controlled hypothermia when the EEG becomes flat. 9. Monitoring of the pathophysiological conditions after severe head trauma and the effects of therapy. 10. An intraoperative warning device of unsuspected awareness during light anesthesia when movement is abolished by muscle relaxants and cardiovascular responses are modified by vasoactive drugs. In case of the latter the stimulus is a small electrical potential applied to the skin of the hand. Thereafter, the stimulus travels along the specific nervous pathways inducing (= generating) potential activation at various sites. The generation of potential changes at various sites along the pathway is an index for the integrity of the nerve. Thus, the evoked potential can be considered a neurophysiological response (usually of the cortex) to impulses originating from some externally stimulated sensory nerve. They provide a physiological measure of the functional integrity of the sensory nerve pathway, which can be used as a clinical diagnostic tool as well as for intraoperative monitoring. The evoked potential usually is recorded from the specific cortical area corresponding to the stimulus input. The classification of evoked potentials. Stimulating a sensory nervous pathway induces evoked potentials. If the auditory nerve is stimulated by "clicks" from headphones, it is called the auditory evoked potential (AEP). The early part of the AEP waveform (less than 10 msec) is called the Brainstem Auditory Evoked Potential (BAEP) since it reflects the passing of the impulse through the brainstem. If a nerve on the arm or the leg is stimulated by a small electrical current applied to the overlying skin, it is called the Somatosensory Evoked Potential (SSEP). If, however, the retina is stimulated by means of flicker light or a sudden change in a checkerboard pattern, the evoked potential thus recorded over the corresponding cortical area is called the Visual Evoked Potential (VEP). Evoked potentials are used both as a diagnostic tool and as a monitoring technique. As diagnostic tests, evoked potentials are useful to evaluate neurologic disorders such as: a) multiple sclerosis, b) acoustic nerve tumors, a

Freye, Enno

2005-04-01

259

Auditory evoked potentials in a stranded Gervais' beaked whale (Mesoplodon europaeus).  

PubMed

Efforts to identify the specific causal mechanisms responsible for beaked whale strandings coincident with naval exercises have been hampered by lack of data concerning the hearing abilities of beaked whales and their physiological and behavioral responses to sound. In this study, auditory capabilities of a stranded Gervais' beaked whale (Mesoplodon europaeus) were investigated by measuring auditory evoked potentials. Click-evoked potentials, auditory thresholds as a function of frequency, and the modulation rate transfer function were determined. The evoked potentials and modulation rate transfer function were similar to those measured in other echolocating odontocetes; the upper limit of functional hearing was 80-90 kHz. PMID:19603906

Finneran, James J; Houser, Dorian S; Mase-Guthrie, Blair; Ewing, Ruth Y; Lingenfelser, Robert G

2009-07-01

260

Visual evoked potentials and magnocellular and parvocellular segregation.  

PubMed

We have measured visual evoked potentials (VEPs) to luminance-modulated, square-wave alternating, 3-deg homogeneous disks for stimulus frequencies ranging from 1 Hz to 16.7 Hz. The aim of the study was to determine the range of frequencies at which we could reproduce the two-branched contrast-response (C-R) curves we had seen at 1 Hz (Valberg & Rudvin, 1997) and which we interpreted as magnocellular (MC) and parvocellular (PC) segregation. Low-contrast stimuli elicited relatively simple responses to luminance increments resulting in waveforms that may be the signatures of inputs from magnocellular channels to the visual cortex. At all frequencies, the C-R curves of the main waveforms were characterized by a steep slope at low contrasts and a leveling off at 10%-20% Michelson contrast. This was typically followed by an abrupt increase in slope at higher contrasts, giving a distinctive two-branched C-R curve. On the assumption that the low-contrast, high-gain branch reflects the responsivity of magnocellular-pathway inputs to the cortex, the high-contrast branch may be attributed to additional parvocellular activation. While a two-branched curve was maintained for frequencies up to 8 Hz, the high-contrast response was significantly compromised at 16.7 Hz, revealing a differential low-pass filtering. A model decomposing the measured VEP response into two separate C-R curves yielded a difference in sensitivity of the putative MC- and PC-mediated response that, when plotted as a function of frequency, followed a trend similar to that found for single cells. Due to temporal overlap of responses, the MC and PC contributions to the waveforms were hard to distinguish in the transient VEP. However, curves of time-to-peak (delay) as a function of contrast often went through a minimum before the high-contrast gain increase of the corresponding C-R curve, supporting the notion of a recruitment of new cell ensembles in the transition from low to high contrasts. PMID:11016577

Rudvin, I; Valberg, A; Kilavik, B E

261

Relationships between Electrically Evoked Potentials and Loudness Growth in Bilateral Cochlear Implant Users  

PubMed Central

SHORT SUMMARY Bilateral cochlear implantation has motivated efforts to ensure that sounds presented at equal levels to each ear are perceived as equally loud. Psychophysical loudness balancing is not always practical, especially with pediatric users. Electrophysiological potentials -- electrically evoked auditory brain stem response (EABR) and electrically evoked compound action potential (ECAP) measures -- may provide a means of approximating loudness balance. It was hypothesized that stimuli evoking equal amplitude neural responses would be more closely matched in loudness than stimuli with equal current levels. No significant differences in loudness discrepancy across ears were found for ECAP, EABR or matched current levels.

Kirby, Benjamin; Brown, Carolyn; Abbas, Paul; Etler, Christine; O'Brien, Sara

2011-01-01

262

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

National Technical Information Service (NTIS)

Interhemispheric difference in visual evoked potential amplitude were measured in 32 right handed sonar operators. Each operators was also rated by his supervisor as to his performance using visual sonar displays. Significant interhemispheric asymmetries ...

C. L. Schlichting S. W. Kindness

1981-01-01

263

Ocular vestibular evoked myogenic potentials produced by impulsive lateral acceleration in unilateral vestibular dysfunction  

Microsoft Academic Search

ObjectiveTo deduce the connectivity underlying ocular vestibular evoked myogenic potentials (OVEMPs) recorded from two sites and produced by lateral transmastoid stimulation in patients with unilateral vestibular dysfunction.

Sendhil Govender; Sally M. Rosengren; Neil P. McAngus Todd; James G. Colebatch

2011-01-01

264

Vestibular evoked myogenic potentials in patients with benign paroxysmal positional vertigo involving each semicircular canal  

Microsoft Academic Search

PurposeWe have investigated vestibular evoked myogenic potentials (VEMPs) as a function of age and the involvement of each of the 3 semicircular canals in patients with benign paroxysmal positional vertigo (BPPV).

Seok Min Hong; Dong Choon Park; Seung Geun Yeo; Chang Il Cha

2008-01-01

265

Ocular vestibular-evoked myogenic potentials elicited from monaural versus binaural acoustic stimulations  

Microsoft Academic Search

ObjectiveThis study compared the ocular vestibular-evoked myogenic potentials (oVEMPs) that are elicited (recorded) in response to monaural and separately, simultaneous binaural acoustic stimulations. The optimal stimulation mode for oVEMPs was also determined.

Shou-Jen Wang; Fu-Shan Jaw; Yi-Ho Young

2009-01-01

266

The vestibular evoked myogenic potential: A test–retest reliability study  

Microsoft Academic Search

ObjectiveThe purpose of this study was to evaluate the reliability of the vestibular evoked myogenic potential (VEMP) response in a clinical setting when only a feedback mechanism is available for monitoring background EMG.

Leen Maes; Bart M. Vinck; Eddy De Vel; Wendy D’haenens; Annelies Bockstael; Hannah Keppler; Birgit Philips; Freya Swinnen; Ingeborg Dhooge

2009-01-01

267

Cervical vestibular evoked myogenic potentials (cVEMPs) in patients with superior canal dehiscence syndrome (SCDS)  

Microsoft Academic Search

ObjectiveTo determine the usefulness of both amplitude and threshold data from tone-burst cervical vestibular evoked myogenic potential (cVEMP) testing for the evaluation of superior canal dehiscence syndrome (SCDS).

Rachel E. Roditi; Robert W. Eppsteiner; Todd B. Sauter; Daniel J. Lee

2009-01-01

268

EVOKED POTENTIALS AS INDICES OF ADAPTATION IN THE SOMATOSENSORY SYSTEM IN HUMANS: A REVIEW AND PROSPECTUS  

EPA Science Inventory

Population-level behavior of large neural aggregates can be efficiently monitored by corresponding population-level indices such as somatosensory evoked potentials (SEPs). The literature reviewed clearly indicates that SEPs undergo systematic and often marked changes under condit...

269

Studies on Accurate Measurements and Analyses of Human Olfactory Evoked Potentials.  

National Technical Information Service (NTIS)

Several techniques were developed to measure human olfactory evoked potentials (OEPs). Waveforms of the OEPs were recorded when perceived. Techniques for rejecting the contaminants and preventing various kinds of noise are described. The saturation phenom...

M. Tonoike

1986-01-01

270

Frequency Analysis of Visual Evoked Potentials from Anesthetized 'Macaca nemestrina' using Power Spectra Estimates.  

National Technical Information Service (NTIS)

The effects of varying intensity and retinal loci on the monkey visual evoked potential (VEP) were determined by frequency analysis. Frequency information in the VEP was investigated by use of the Fast Fourier Transform (FFT), the FFT output being represe...

G. W. Lewis

1972-01-01

271

Temperature-Dependent Changes in Visual Evoked Potentials of Rats (Journal Version).  

National Technical Information Service (NTIS)

The effects of alterations in body temperature on flash and pattern reversal evoked potential (FEPs and PREPs) were examined in hooded rats whose thermoregulatory capacity was compromised with lesions of the preoptic/anterior hypothalamic area and/or cold...

B. E. Hetzler W. K. Boyes J. P. Creason R. S. Dyer

1988-01-01

272

Real-Time Frequency Analysis Methodology for Evoked Potential Loop-Closure.  

National Technical Information Service (NTIS)

Evoked EEG response research indicates the potential for a usable brain actuated control system. Reduction of time lag is essential for the continued development of our subject training system, which has yielded results, but has certain limitations in the...

J. H. Schnurer D. F. Ingle C. W. Downey A. M. Junker

1988-01-01

273

Transcranial Magnetic Stimulation Evokes Giant Inhibitory Potentials in Children  

Microsoft Academic Search

The electroencephalographic response to transcranial magnetic stimulation (TMS) recently has been established as a direct parameter of motor cortex excitability. Its N100 component was suggested to reflect an inhibitory response. We investigated influences of cerebral maturation on TMS-evoked N100 in 6- to 10-year-old healthy children. We used a forewarned reaction time (contingent negative variation) task to test the effects of

Stephan Bender; Kristine Basseler; Imke Sebastian; Franz Resch; Thomas Kammer; Rieke Oelkers-Ax; Matthias Weisbrod

2005-01-01

274

Statistical Evoked Potential Detection with Number of Degrees of Freedom Estimated from EEG Autocorrelation Function  

Microsoft Academic Search

\\u000a Statistical Objective Response Detection (ORD) Techniques applied to Evoked Potentials usually depend on the effective Number\\u000a of Degrees of Freedom (NDOF) of spontaneous EEG. This work proposes a method for estimating the NDOF of the EPD (Evoked Potential Detector) probability distribution under the null hypothesis of no response, based on the EEG autocorrelation function (ACF). Its\\u000a performance was assessed by

Maurício Cagy; A. Fernando C. Infantosi; A. M. F. L. Miranda Sá; David M. Simpson

275

The Effect of Stimulation Frequency and Retinal Stimulus Location on Visual Evoked Potential Topography  

Microsoft Academic Search

The activity of cortical neurons is influenced by retinal stimulus location and temporal modulation. We investigated how reversal\\u000a frequency of black-and-white checkerboard patterns presented in different parts of the visual field affects evoked potential\\u000a topography. Visual evoked potentials were recorded from an array of 16 electrodes over the occipital cortex in 12 healthy\\u000a adults. A checkerboard reversal stimulus (40? check

Wolfgang Skrandies

2007-01-01

276

Facilitation of cortically evoked potentials with motor imagery during post-exercise depression of corticospinal excitability  

Microsoft Academic Search

This study examined whether muscle fatigue alters the facilitatory effect of motor imagery on corticospinal excitability. We aimed to determine if post-exercise depression of potentials evoked magnetically from the motor cortex is associated with alterations in internally generated movement plans. In experiment 1, motor-evoked potentials (MEPs) were recorded from two right hand and two right forearm muscles, at rest and during

Julia B. Pitcher; Alexandra L. Robertson; Emma C. Clover; Shapour Jaberzadeh

2005-01-01

277

Artefact cancellation in motor-sensory evoked potentials: two approaches using adaptive filtration and exponential approximation  

Microsoft Academic Search

Adaptive filtering for artefact cancellation in motor-sensory evoked potentials using signals obtained by subtraction methods\\u000a (double-stimulus, off-nerve and subthreshold) is proposed. This is advantageous as inherent non-linear distortions can be\\u000a overcome in an easier way by adaptive filtering. Efficiency is assessed with reference signals synthesised by varying the\\u000a shape and reducing the amplitude of a ‘pure’ evoked potential in the

I. Dotsinsky; A. Dos Santos; I. Tashev

1999-01-01

278

Influence of motor unit properties on the size of the simulated evoked surface EMG potential  

Microsoft Academic Search

The purpose of the study was to quantify the influence of selected motor unit properties on the simulated amplitude and area\\u000a of evoked muscle potentials detected at the skin surface. The study was restricted to a motor unit population simulating a\\u000a hand muscle whose potentials were recorded on the skin over the muscle. Peak-to-peak amplitude and area of the evoked

Kevin G. Keenan; Dario Farina; Roberto Merletti; Roger M. Enoka

2006-01-01

279

Observations on intraoperative somatosensory evoked potential (SEP) monitoring in the semi-sitting position  

Microsoft Academic Search

Background: Former case reports suggest that monitoring of median nerve somatosensory evoked potentials (M-SEP) is unreliable in patients operated in the semi-sitting position due to the occurrence of evoked potential changes unrelated to neurological damage. This study was designed to analyze these changes in greater detail and confirm that these changes are not caused by neurological damage.Methods: M-SEP monitoring findings

Helmut Wiedemayer; Heike Schaefer; W Armbruster; M Miller; Dietmar Stolke

2002-01-01

280

Dynamic grid self-organizing map for clustering of visual evoked potential single trials  

Microsoft Academic Search

The paper develops a novel learning model of clustering for evoked potential single trials, called dynamic grid self-organized map (DG-SOM) designed according to the peculiarities of evoked potential data. The DG-SOM determines adaptively the number of clusters with a dynamic extension process which is able to exploit class information whenever it exists. Specifically, it accepts available class information to control

Maria Stavrinou; S. Papadimitriou; Anustasios Bezerianos; P. Papathanasopoulos

2002-01-01

281

A subspace approach with pre-whitening for measurements of latencies in visual evoked potentials  

Microsoft Academic Search

Estimating a visual evoked potential (VEP) from the human brain is challenging since its signal-to-noise ratio (SNR) is generally very low-as low as -10 dB. Visual evoked potentials are conventionally extracted from the spontaneous brain activity by collecting a series of time-locked electroencephalogram (EEG) epochs and performing multitrial ensemble averaging on these samples to improve the SNR. Alternatively, a VEP

Mohd Zuki Yusoff; Nidal Kamel

2010-01-01

282

Visual evoked potentials in humans during recognition of emotional facial expressions  

Microsoft Academic Search

Visual evoked potentials were recorded from the occipital, parietal, central, frontal, and posterior temporal areas of the\\u000a cortex during recognition of emotionally positive, negative and neutral facial expressions and during passive observation\\u000a in 22 right-handed healthy subjects. These studies showed that in the posterior temporal areas, the latencies of the N90,\\u000a P150, and N180 waves of potentials evoked by faces

E. S. Mikhailova; D. V. Davydov

1999-01-01

283

Color-coded pattern suppresses visual evoked cortical potentials and electroretinograms  

Microsoft Academic Search

We developed a new visual stimulating system for recording visual evoked cortical potentials and electroretinograms. The stimulus\\u000a was a color checkerboard, in which each check kept its chromaticity but changed its luminance with its corresponding check.\\u000a Color-coded pattern stimuli using red and green checks did not produce visual evoked cortical potentials, while yellow checks\\u000a produced clear responses in a normal

Yoshiaki Shimada; Koichiro Murayama; Emiko Adachi-Usami

1996-01-01

284

Retinocortical conduction time in diabetics with abnormal pattern reversal electroretinograms and visual evoked potentials  

Microsoft Academic Search

Clinically evident retinal vascular disease in patients with diabetes mellitus may be preceded by an increase in visual evoked potential latency in electrophysiologic testing. This increase may indicate either retinal or optic nerve dysfunction. To determine the origin of the latency increase we initiated a cross-sectional study of simultaneous pattern-reversal electroretinograms and visual evoked potentials. We recorded transient (3.8 reversals\\/second)

Gary L. Trick; Ronald M. Burde; Mae O. Gordon; Charles Kilo; Julio V. Santiago

1988-01-01

285

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

Microsoft Academic Search

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

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

2007-01-01

286

Evaluation of brain function in acute carbon monoxide poisoning with multimodality evoked potentials  

SciTech Connect

The median nerve somatosensory evoked potentials (SEP), pattern reversal visual evoked potentials (VEP), and brain stem auditory evoked potentials (BAEP) were studied in 109 healthy adults and in 88 patients with acute carbon monoxide (CO) poisoning. The upper limits for normal values of peak and interpeak latencies of multimodalities of evoked potentials in the reference group were established by a stepwise multiple regression analysis. SEP changes selectively affecting N32 and N60 were found in 78.8% of patients. There was prolonged PI00 latency of VEP in 58.2% of the cases examined. The prevalence of BAEP abnormalities in comatose patients (36%) was significantly higher than that (8.6%) in conscious patients. BAEP abnormalities were most frequently seen in comatose patients who had diminished brain stem reflexes (77.8%). It has been found that a consistent abnormality involving N2O and subsequent peaks in SEP, a remarkable prolongation of PI00 latency in VEP, or a prolongation of Ill-V interpeak latency in BAEP as well as the reoccurrence of evoked potential abnormalities after initial recovery all indicate unfavorable outcomes in patients with acute CO poisoning. The multimodality evoked potentials have proved to be sensitive indicators in the evaluation of brain dysfunction and in the prediction of prognosis of acute CO poisoning and the development of delayed encephalopathy. 16 refs., 4 figs., 6 tabs.

He, Fengsheng; Liu, Xibao; Yang, Shi; Zhang, Shoulin (Institute of Occupational Medicine, Beijing (China)); Xu, Guanghua; Fang, Guangchai; Pan, Xiaowen (Navy Hospital, Beijing (China))

1993-02-01

287

[Effect of binaural conductive hearing loss on maturation of acoustically evoked potentials (auditory brain stem response, middle latency response) in guinea pigs].  

PubMed

During the early development of the acoustic system a conductive hearing loss may alter the maturation of acoustically evoked potentials and affect the development of hearing. The present experiments were carried out in newborn guinea pigs with binaural conductive hearing loss. The external ear canals were plugged over a period of one month from the first day postpartum. During and after deprivation click-evoked Auditory Brainstem Responses (ABR) and Middle Latency Responses (MLR) were collected to analyze changes in the maturation of these potentials in comparison to untreated animals. This type of deprivation is characterized by threshold elevations of about 40 dB over a wide frequency range. In young deprived animals, ABR Latencies (PIII, PV) and interpeak latencies exhibited a significant delay with a maximum between day 13 and 19, which disappeared within 10 days after the end of the treatment. MLR latencies were also significantly affected after three to four weeks of the deprivation phase. In contrast to the ABR, the recovery of the latencies was completed within four to six weeks. These results therefore indicate that a conductive hearing loss may alter the maturation of the acoustically evoked responses in the sensitive phase after birth. This type of partial deprivation may affect the development of hearing and speech perception in children with chronically occurring otitis media. PMID:2604818

Walger, M; Ferreira, P; Laska, M; Schneider, I; von Wedel, H

1989-11-01

288

Effects of Glutamate Receptor Agonists on the P13 Auditory Evoked Potential and Startle Response in the Rat  

PubMed Central

The P13 potential is the rodent equivalent of the P50 potential, which is an evoked response recorded at the vertex (Vx) 50?ms following an auditory stimulus in humans. Both the P13 and P50 potentials are only present during waking and rapid eye movement (REM) sleep, and are considered to be measures of level of arousal. The source of the P13 and P50 potentials appears to be the pedunculopontine nucleus (PPN), a brainstem nucleus with indirect ascending projections to the cortex through the intralaminar thalamus, mediating arousal, and descending inhibitory projections to the caudal pontine reticular formation (CPRF), which mediates the auditory startle response (SR). We tested the hypothesis that intracranial microinjection (ICM) of glutamate (GLU) or GLU receptor agonists will increase the activity of PPN neurons, resulting in an increased P13 potential response, and decreased SR due to inhibitory projections from the PPN to the CPRF, in freely moving animals. Cannulae were inserted into the PPN to inject neuroactive agents, screws were inserted into the Vx in order to record the P13 potential, and electrodes inserted into the dorsal nuchal muscle to record electromyograms and SR amplitude. Our results showed that ICM of GLU into the PPN dose-dependently increased the amplitude of the P13 potential and decreased the amplitude of the SR. Similarly, ICM of N-methyl-d-aspartic acid or kainate into the PPN increased the amplitude of the P13 potential. These findings indicate that glutamatergic input to the PPN plays a role in arousal control in vivo, and changes in glutamatergic input, or excitability of PPN neurons, could be implicated in a number of neuropsychiatric disorders with the common symptoms of hyperarousal and REM sleep dysregulation.

Simon, Christen; Wallace-Huitt, Tiffany; Thapa, Priyenka; Skinner, Robert D.; Garcia-Rill, Edgar

2010-01-01

289

Development of brainstem auditory pathway in mallard duck embryos and hatchlings  

Microsoft Academic Search

The development of the brainstem auditory evoked potential (BAEP) was studied in mallard duck (Anas platyrhynchos) embryos and hatchlings from 5–6 days before hatching through two days after hatching in response to tone pips of different frequencies. BAEPs showed a different time of onset and a different rate of development for low, middle, and high frequencies. Although auditory sensitivity in

Lubov P. Dmitrieva; Gilbert Gottlieb

1992-01-01

290

A Case of Bickerstaff's Brainstem Encephalitis with Guillain-Barré Syndrome Presenting Optic Neuropathy and Seizure  

Microsoft Academic Search

Bickerstaff's brainstem encephalitis (BBE), characterized by acute ophthalmoplegia and ataxia, often causes impaired consciousness and hyperreflexia. A 17-year-old man was admitted with an acute meningitic condition including high and neck stiffness. His condition rapidly deteriorated over 2 weeks, and he showed ophthal- moplegia, ataxia, seizure, tetraplegia, comatose mentality, and optic neuropathy. Electroencephalography showed diffuse slow waves. Visual evoked potentials showed

Ji Eun Kim; Jae Hyuk Kwak; O Dae Kwon; Jin Kuk Do; Dong Kuck Lee

291

Detection and multichannel SVD-based filtering of trigeminal somatosensory evoked potentials  

Microsoft Academic Search

Very weak and noisy trigeminal somatosensory evoked potentials (TSEPs) are considered, which are successfully evoked by electrical\\u000a stimulation of the trigeminal nerve of 15 patients with endosseous oral implants. As TSEP analysis provides an objective means\\u000a of assessing neuronal function, it is considered to be a promising tool for investigating tactile sensation through anchoring\\u000a implants in bone. For this purpose,

A. Swinnen; S. Van Huffel; K. Van Loven; R. Jacobs

2000-01-01

292

Gating of somatosensory evoked potentials during voluntary movement of the lower limb in man  

Microsoft Academic Search

Somatosensory evoked potentials (SEPs) evoked by stimulation of the tibial nerve (TN) in the popliteal fossa, the sural nerve\\u000a (Sur) at the lateral malleole, and an Achilles tendon (Achilles) tap were recorded before and during voluntary plantarflexion,\\u000a dorsiflexion, and cocontraction of the ipsi- and contralateral foot in normal subjects. Suppression (gating) of the TN-SEP\\u000a began around 60 ms before the

H. Morita; N. Petersen; J. Nielsen

1998-01-01

293

Evaluation of the vestibular evoked myogenic potential during parabolic flight in humans  

Microsoft Academic Search

The purpose of this study was to investigate how gravity affects the vestibular evoked myogenic potential (VEMP). Eight healthy\\u000a subjects (seven men, one woman; age range 19–45 years) participated in experiments in which three different gravity levels\\u000a [microgravity (MG), normal gravity (NG), and hypergravity (HG)] were imposed during a parabolic flight procedure. The VEMP\\u000a was evoked in response to an intense

Hideo Shojaku; Yukio Watanabe; Masahito Tsubota; Naomi Katayama

2008-01-01

294

Slow excitatory synaptic potentials evoked by distension in myenteric descending interneurones of guinea-pig ileum  

PubMed Central

The functional significance of the slow excitatory synaptic potentials (EPSPs) in myenteric neurones is unknown. We investigated this using intracellular recording from myenteric neurones in guinea-pig ileum, in vitro. In all, 121 neurones responded with fast EPSPs to distension of the intestine oral to the recording site. In 28 of these neurones, distension also evoked depolarizations similar to the slow EPSPs evoked by electrical stimulation in the same neurones. Intracellular injection of biocytin and immunohistochemistry revealed that neurones responding to distension with slow EPSPs were descending interneurones, which were immunoreactive for nitric oxide synthase (NOS). Other neurones, including inhibitory motor neurones and interneurones lacking NOS, did not respond to distension with slow EPSPs, but many had slow EPSPs evoked electrically. Slow EPSPs evoked electrically or by distension in NOS-immunoreactive descending interneurones were resistant to blockade of NK1 or NK3 tachykinin receptors (SR 140333, 100 nm; SR 142801, 100 nm, respectively) and group I metabotropic glutamate receptors (PHCCC, 10–30 ?m), when the antagonists were applied in the recording chamber of a two-chambered organ bath. However, slow EPSPs evoked electrically in inhibitory motor neurones were substantially depressed by SR 140333 (100 nm). Blockade of synaptic transmission in the stimulation chamber of the organ bath abolished slow EPSPs evoked by distension, indicating that they arose from activity in interneurones, and not from anally directed, intrinsic sensory neurones. Thus, distension evokes slow EPSPs in a subset of myenteric neurones, which may be important for intestinal motility.

Thornton, P D J; Bornstein, J C

2002-01-01

295

On the relationship between nociceptive evoked potentials and intraepidermal nerve fiber density in painful sensory polyneuropathies.  

PubMed

This study analyzed the relationship between the density of intraepidermal nerve fibers (IENF) and the characteristics of either nociceptive laser-evoked potentials (LEPs) or contact heat-evoked potentials (CHEPs) in patients with painful sensory polyneuropathy with the aim to determine which parameters of LEPs and CHEPs more reliably reflect IENF loss. A total of 96 patients and 35 healthy volunteers took part in the study. Based on clinical examination, nerve conduction tests, and quantitative sensory testing, we identified 52 patients with small-fiber neuropathy (SFN), 40 with mixed (small-fiber and large-fiber) neuropathy (MFN), and 4 who were excluded from the analysis because of no evidence of involvement of small fibers. The latency of the N2 was delayed for both LEPs and CHEPs in patients with MFN and for CHEPs only in patients with SFN. The amplitude of the vertex N2/P2 potential was similarly reduced in both types of neuropathy, but LEPs were more frequently absent than CHEPs in MFN patients (68% vs 40%). In general, latency and amplitude of LEPs and CHEPs were well correlated with IENF density. SFN patients were characterized by abnormal EPs and slightly decreased but morphologically abnormal IENF. MFN patients were characterized by frequently absent LEPs and CHEPs and a rather severe IENF loss. The correlation between nociceptive evoked potentials (laser-evoked potentials and contact heat-evoked potentials) and skin biopsy aids in the diagnosis of painful neuropathies. PMID:21185650

Casanova-Molla, Jordi; Grau-Junyent, Josep Maria; Morales, Merche; Valls-Solé, Josep

2010-12-24

296

Binaural interaction in specific language impairment: an auditory evoked potential study.  

PubMed

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 impairment (SLI). Binaural interaction components (BICs) in the brainstem were compared in 19 children with SLI (13 males, six females; age range 7y 4mo-11y 10mo; mean age 9y 7mo [SD 1y 2mo]), and 31 comparison children with typical language development (16 males, 15 females; age range 7y 1mo-11y 4mo; mean age 9y 7mo [SD 1y 5mo]). Children with SLI had a significantly smaller BIC amplitude than the comparison group. However, no clear relationship was found between BIC measures and severity of language impairment. We conclude that, for some children, SLI may be associated with reduced binaural interaction which may hinder the detection or localization of speech sounds from noisy contexts during critical periods of language acquisition. PMID:17376138

Clarke, Elaine M; Adams, Catherine

2007-04-01

297

GLUTATHIONE DEFICIENCY POTENTIATES MANGANESE TOXICITY IN RAT STRIATUM AND BRAINSTEM AND IN PC12 CELLS  

Microsoft Academic Search

Levels of dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), noradrenaline (NA), glutathione (GSH), ascorbic acid (AA), dehydroascorbic acid (DHAA) and uric acid (UA) were determined in the striatum and\\/or in the brainstem of 3-month-old male Wistar rats after subchronic oral exposure to MnCl2(20 mg kg?1daily) alone or associated to buthionine(S,R)sulphoximine-ethyl ester (BSO-E), an inhibitor of GSH synthesis. The NA,

M. S. Desole; G. Esposito; R. Migheli; S. Sircana; M. R. Delogu; L. Fresu; M. Miele; G. de Natale; E. Miele

1997-01-01

298

Estimation of trial-to-trial variation in evoked potential signals by smoothing across trials.  

PubMed

Averaging single trial evoked potential data to produce an estimate of the underlying signal obscures trial-to-trial variation in the response. We describe a method for estimating slow changes in the evoked potential signal by smoothing the data over trials. We discuss the crucial issue of deciding how much to smooth and suggest that an appropriate smoothing parameter is one that minimizes the estimated mean average square error of the smoothed data. Equations to estimate the mean average square error for a one-dimensional local linear regression smoother are presented. Performance of the method is assessed using simulated evoked potential data with several different models of a changing signal and different values of the signal-to-noise ratio. We find that the method rarely imputes trial-to-trial variation to data sets that have an unchanging signal, while it almost always produces less error than averaging when estimating a varying signal. The ability of the method to reveal signal heterogeneity is hampered by very low signal-to-noise ratios. When applied to real auditory evoked potential data from a sample of elderly subjects, the method indicated a changing signal in 35% of all subjects and in 56% of subjects with signal-to-noise ratios above 0.6. Consistent patterns of variation in the auditory evoked potential were present in this sample. PMID:2629018

Turetsky, B I; Raz, J; Fein, G

1989-11-01

299

Abnormal somatosensory evoked potentials in patients with classic galactosemia: correlation with neurologic outcome.  

PubMed

In classic galactosemia, long-term neurologic sequelae can include low cognitive functioning and a curious neurologic syndrome with tremors, dysmetria, and ataxia. An abnormal white-matter signal on cerebral magnetic resonance imaging (MRI) is present in almost all patients; some have mild cerebral or cerebellar atrophy and focal white-matter lesions. The present study was undertaken to assess the integrity of myelinated pathways by recording somatosensory evoked potentials. Results were correlated with age at diagnosis, severity of illness, age at evoked potentials, neurologic examination, MRI studies and cognitive outcome as measured by the Woodcock-Johnson Revised Standard Cognitive Battery. Evoked potentials were abnormal in 17 (28%) of 60 patients who had median nerve, and 26 (77%) of 34 patients who had posterior tibial nerve studies. Abnormalities of the central rather than the peripheral nervous system were most common. Evoked potentials correlated with severity of presenting symptoms (P = .011), age at evoked potential testing (P = .029), and presence of focal white-matter lesions on MRI (P = .049). Results of neurophysiologic testing showed no correlation with the Woodcock-Johnson Battery. Patients with classic galactosemia may have abnormal conduction along myelinated pathways that is associated with other central deficits. Myelin, which contains galactose, may be adversely affected in this inborn error of metabolism. PMID:7769175

Kaufman, F R; Horton, E J; Gott, P; Wolff, J A; Nelson, M D; Azen, C; Manis, F R

1995-01-01

300

The effect of cerebral lymphatic blockage on cortex regional cerebral blood flow and somatosensory evoked potential.  

PubMed

Disputes on the significance of cerebral lymphatic drainage pathways under physiological and pathophysiological conditions still exist. The purpose of this experiment is to investigate the influence of cerebral lymphatic blockage on cerebral blood flow and cortex somatosensory evoked potential. Wistar rat cerebral lymphatic blockage models were established by removing cervical lymphatic nodes after obstructing their input and output tubes. Animals were divided randomly into a sham-operated group and a cerebral lymphatic-blockage group. Regional cerebral blood flow in different regions of the cortex were detected using a laser-Doppler flowmeter probe, and cortex evoked potential was detected using an electromyogram and evoked potential instrument before the operation, then 1 day, 5 days and 7 days after the operation. Results showed that the sham operation had no obvious effect on regional cerebral blood flow and the latency of somatosensory evoked potential. From 1 day to 7 days after cerebral lymphatic obstruction, regional cerebral blood flow in different cortical regions decreased markedly (P<0.01). Latency of somatosensory evoked potential was significantly delayed on the 5th and 7th day after blockage of cerebral lymphatic drainage (P<0.01). We concluded that cerebral lymphatic drainage may play an important role in maintaining the equilibrium of the internal environment of the brain, and blockage of this pathway results in cerebral ischemia. PMID:14724360

Xia, Zuo-Li; Sun, Bao-Liang; Yang, Ming-Feng; Yuan, Hui; Qiu, Ping-Ming; Chen, Yu-She

2003-01-01

301

The use of magnetic motor evoked potentials in horses with cervical spinal cord disease.  

PubMed

The aim of this study was to investigate the use of magnetic motor evoked potentials as an ancillary diagnostic test in horses with cervical cord lesions. Transcranial magnetic stimulation was performed in 12 ataxic horses and the results of the evoked responses were compared to those found in normal horses. The latency and peak-to-peak amplitude of the potentials in the 12 ataxic horses were significantly different from those measured in normal horses. The configuration of the abnormal potentials was also polyphasic. Normalisation of the evoked potentials occurred in none of the horses, presented after a period of clinical improvement. These findings demonstrate that the technique is also able to detect lesions in horses with subtle clinical signs of incoordination. Magnetic transcranial stimulation is a valuable ancillary test to assess the integrity of the motor tracts. The technique is painless and safe and shows good sensitivity to detect lesions along the descending motor pathways. PMID:11902758

Nollet, H; Deprez, P; Van Ham, L; Verschooten, F; Vanderstraeten, G

2002-03-01

302

Effects of sedative and hypnotic drug combinations on transcranial magnetic motor evoked potential, bispectral index and ARX-derived auditory evoked potential index in dogs.  

PubMed

Relationships between onset latency and peak-to-peak amplitude of magnetic motor evoked potentials (MMEP) after transcranial magnetic stimulation (TMS), together with the electroencephalographic parameters bispectral analysis index (BIS) and the autoregressive model with exogenous input (ARX)-derived auditory evoked potential index (AAI) were explored during different sedative and hypnotic drug combinations in six dogs. TMS was performed under sedation with acepromazine/methadone or medetomidine and after a single bolus injection of propofol or etomidate. Data for BIS and AAI were continuously collected during the periods of treatment with the hypnotic drugs. Changes in BIS and AAI during both periods were not statistically correlated with changes in onset latencies and peak-to-peak amplitudes of MMEP after TMS. Therefore, both electroencephalographic techniques are of limited use in titrating sedation and anaesthesia during TMS in the dog. PMID:18682332

Van Soens, Iris; Struys, Michel M; Polis, Ingeborgh E; Tshamala, Mulenda; Nollet, Heidi; Bhatti, Sofie F; Van Ham, Luc M

2008-08-03

303

Aging affects transcranial magnetic modulation of hippocampal evoked potentials.  

PubMed

Transcranial magnetic stimulation (TMS) is being proposed as a method of choice for the treatment of clinical depression, yet its action in the brain is still not well understood. In previous studies we found that TMS has a long-term effect on reactivity of the hippocampus to perforant path stimulation. Since the efficacy of antidepressants is highly age-dependent, we studied possible age-related effects of TMS on hippocampal evoked responses. Young adult (3 months), aging (10 months) and aged (24-26 months) awake rats were subjected to daily TMS for one week, followed by measurements of several parameters of reactivity to perforant path stimulation in the anesthetized rat. TMS did not affect responses of the hippocampus to single perforant path stimulation, but reduced drastically paired-pulse and frequency dependent depression in the young and aging but not the old rats. Likewise, TMS increased LTP expression in the young but not the old rats, and reduced the efficacy of serotonin modulation of reactivity of the hippocampus, in the young but not the old rats. Thus, long term effects of chronic TMS on local GABAergic inhibition are highly age dependent. PMID:11182475

Levkovitz, Y; Segal, M

304

Sex-related hemispheric lateralization of electrical potentials evoked by arousing negative stimuli  

Microsoft Academic Search

Recent studies suggest that both sex and cerebral hemisphere influence brain mechanisms associated with emotional memory. Here we used evoked potentials to examine the influence of sex and hemisphere on brain responses to emotional stimuli. Given that the P300 component of the event-related brain potential (ERP) is considered a cognitive neuroelectric phenomenon, we compared left and right hemisphere P300 responses

Antonella Gasbarri; Benedetto Arnone; Assunta Pompili; Francesca Pacitti; Claudio Pacitti; Larry Cahill

2007-01-01

305

Effect of raising body temperature on visual and somatosensory evoked potentials in patients with multiple sclerosis  

Microsoft Academic Search

The effects of raising body temperature on the visual (VEP) and somatosensory (SEP) evoked potentials were observed in normal subjects and in patients with multiple sclerosis. The amplitude of the VEP was significantly reduced to the same degree after heating in normal subjects and in patients with multiple sclerosis but there was no effect on the latency of the potential.

W B Matthews; D J Read; E Pountney

1979-01-01

306

Auditory Evoked Potentials and Hand Preference in 6-Month-Old Infants: Possible Gender-Related Differences in Cerebral Organization  

Microsoft Academic Search

Normal 6-month-old infants (10 male and 10 female) were studied to determine if cortical auditory evoked potentials recorded to probe stimuli during verbal and musical stimulus presentation provided an index of cerebral functional organization. Furthermore, evoked potential left–right amplitude asymmetries were examined in relation to gender differences and hand-reaching preference in these infants. Six-month-old girls exhibited evoked potential amplitude asymmetries

Janet L. Shucard; David W. Shucard

1990-01-01

307

Efficacy of transcranial motor-evoked myogenic potentials to detect spinal cord ischemia during operations for thoracoabdominal aneurysms  

Microsoft Academic Search

Objective: Motor-evoked myogenic potentials after transcranial electrical stimulation monitor the vulnerable motoneuronal system of the spinal cord. This study reports our initial experiences with motor-evoked potentials to assess the adequacy of spinal cord perfusion during operations for thoracoabdominal aneurysms. Methods: In 20 patients undergoing thoracoabdominal aneurysm operations, myogenic motor-evoked potentials were recorded. In 18 patients retrograde aortic perfusion was used.

Peter de Haan; Cor J. Kalkman; Bas A. de Mol; Leon H. Ubags; Dirk J. Veldman; Michael J. H. M. Jacobs

1997-01-01

308

The effect of stimulation frequency and retinal stimulus location on visual evoked potential topography.  

PubMed

The activity of cortical neurons is influenced by retinal stimulus location and temporal modulation. We investigated how reversal frequency of black-and-white checkerboard patterns presented in different parts of the visual field affects evoked potential topography. Visual evoked potentials were recorded from an array of 16 electrodes over the occipital cortex in 12 healthy adults. A checkerboard reversal stimulus (40' check size) was presented with frequencies between 1.95 reversals/s and 7.81 reversals/s in the center or in the left or right hemiretina. Evoked potential fields displayed the well-known components of pattern reversal evoked activity. Computation of FFT and wavelets displayed electrical brain responses directly related to stimulation frequency. Further analysis showed that both retinal stimulus location and stimulation frequency affected visual evoked activity. Field strength as well as scalp field topography changed significantly with different reversal frequency. In addition, the pattern of lateralization of components also depended on temporal frequency of stimulation. Electrical brain activity elicited by visual stimuli shows globally similar features which are modulated by stimulus location and frequency. Our results indicate that--at least partly--different neuronal assemblies are activated by stimuli of different temporal characteristics. PMID:17587164

Skrandies, Wolfgang

2007-06-21

309

Segmental inhibition of cutaneous heat sensation and of laser-evoked potentials by experimental muscle pain.  

PubMed

The aim of the study was to evaluate the effect of tonic muscle pain evoked by injection of 5% hypertonic saline in the right brachioradialis muscle on the somatosensory sensation of laser-evoked heat pain and laser-evoked potentials. The heat pain pathways were studied in 9 healthy human subjects by recording the scalp potentials evoked by CO(2) laser stimuli delivered on four sites: the skin above the right brachioradialis muscle (ipsilateral local pain), the wrist area where muscle pain was referred in all subjects (ipsilateral referred pain), and two areas on the left arm symmetrical to both local and referred pain (contralateral local pain and contralateral referred pain). Laser-evoked potentials were obtained from 31 scalp electrodes before saline injection, during saline infusion (bolus injection with 0.3 ml saline infused over 20 s, followed by a steady infusion rate of 30 ml/h for the next 25 min), and 20 min after muscle pain had disappeared. While the early N1/P1 component (around 130 ms and 145 ms of latency after stimulation of the skin over the brachioradialis muscle and the wrist, respectively) was not affected by muscle pain, the amplitudes of the later vertex laser-evoked potentials (N2 latency of around 175 ms and 210 ms after stimulation of the skin over the brachioradialis muscle and the wrist, respectively; P2 latency of around 305 ms and 335 ms after stimulation of the skin over the brachioradialis muscle and the wrist, respectively) evoked from ipsilateral local pain, ipsilateral referred pain, and contralateral local pain sites were significantly decreased during muscle pain compared with the baseline recording, while they recovered after pain had disappeared. At the same stimulation sites, the rating of the laser-evoked pain sensation was reduced significantly during muscle pain as compared with the baseline and it recovered after pain had disappeared. On the contrary, muscle pain did not show any effect on both laser-evoked pain and laser-evoked potential amplitude when the contralateral referred pain site was stimulated. The muscle pain inhibitory effect on both heat pain sensation and laser-evoked potential amplitude is probably mediated by an ipsilateral and contralateral segmental mechanism which acts also on the referred pain area, while more general inhibitory mechanisms, such as a distraction effect or a diffuse noxious inhibitory control, are excluded by the absence of any effect of muscle pain on laser-evoked pain and laser-evoked potentials obtained from a remote site, such as the contralateral referred pain area. Since muscle pain induced by hypertonic saline injection is very similar to clinical pain, our results can be useful in understanding the pathophysiology of the somatosensory modifications which can be observed in patients with musculoskeletal pain syndromes. PMID:16182455

Valeriani, M; Le Pera, D; Restuccia, D; de Armas, L; Maiese, T; Tonali, P; Vigevano, F; Arendt-Nielsen, L

2005-09-21

310

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

PubMed

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. PMID:15250145

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

2004-06-01

311

Effects of upper airway anaesthesia on respiratory-related evoked potentials in humans.  

PubMed

Cortical potentials evoked by mid-inspiratory occlusion arise from numerous receptors, many of which are probably within the upper airway. Their precise nature is not known. The aim of the current study was to improve knowledge of this by studying the effects of topical upper airway anaesthesia on respiratory-related evoked potentials. Respiratory-related evoked potentials were described through the averaging of electroencephalogram (EEG) epochs following mid-inspiratory occlusions (C3-CZ; C4-CZ). A total of 21 healthy volunteers (13 male, aged 22-52 yrs) were studied during mouth breathing, before and after topical upper airway anaesthesia (lidocaine). Moreover, 15 subjects were studied during nose breathing with and without anaesthesia. Six subjects were studied whilst inhaling L-menthol. Typical potentials were present in all the subjects, their components featuring normal amplitudes and latencies. The route of breathing and upper airway anaesthesia did not modify the EEG responses to inspiratory occlusions, qualitatively or quantitatively, during mouth or nose breathing. L-menthol had no effect. Upper airway receptors sensitive to topical anaesthesia are unlikely to contribute significantly to mid-inspiratory occlusion-evoked potentials. On the contrary, deeper receptors, such as joint and muscle receptors, could contribute dominantly to these potentials. PMID:16319342

Redolfi, S; Raux, M; Donzel-Raynaud, C; Morelot-Panzini, C; Zelter, M; Derenne, J-P; Similowski, T; Straus, C

2005-12-01

312

Predictability of Painful Stimulation Modulates the Somatosensory-Evoked Potential in the Rat  

PubMed Central

Somatosensory-evoked potentials (SEPs) are used in humans and animals to increase knowledge about nociception and pain. Since the SEP in humans increases when noxious stimuli are administered unpredictably, predictability potentially influences the SEP in animals as well. To assess the effect of predictability on the SEP in animals, classical fear conditioning was applied to compare SEPs between rats receiving SEP-evoking electrical stimuli either predictably or unpredictably. As in humans, the rat’s SEP increased when SEP-evoking stimuli were administered unpredictably. These data support the hypothesis that the predictability of noxious stimuli plays a distinctive role in the processing of these stimuli in animals. The influence of predictability should be considered when studying nociception and pain in animals. Additionally, this finding suggests that animals confronted with (un)predictable noxious stimuli can be used to investigate the mechanisms underlying the influence of predictability on central processing of noxious stimuli.

Schaap, Manon W. H.; van Oostrom, Hugo; Doornenbal, Arie; Baars, Annemarie M.; Arndt, Saskia S.; Hellebrekers, Ludo J.

2013-01-01

313

[Problems of a frequency-specific threshold measurement with the brainstem potentials using the otometric sound pressure signal (damped wavetrain) (author's transl)].  

PubMed

This study aimes at investigating if the damped wavetrain stimulus (Victoreen) may be used in the evaluation of frequency specific thresholds using brainstem potentials. Stimulus frequencies were 1, 4, and 8 kHz. Starting with a control group (10 persons) latency curves for the brainstem potentials were established. The test group included patients with various forms of sensorineural hearing loss in the audiogram. Threshold measurements at the three stimulus frequencies were done with these patients using the potential IV (Jewet V). The latency curves of the normal hearing control group reveal a frequency-specific information being present in the brainstem potentials. This can be derived from latency shifts at different stimulus frequencies. However, investigating patients with a steep slope or a notch in the pure-tone audiogram introduces some difficulties in the ERA-threshold evaluation. PMID:7458759

Zöllner, C; Pedersen, P

1980-01-01

314

Ultraviolet irradiation of the eye and Fos-positive neurons induced in trigeminal brainstem after intravitreal or ocular surface transient receptor potential vanilloid 1 activation.  

PubMed

The interior structures of the eye are well supplied by the trigeminal nerve; however, the function of these afferent fibers is not well defined. The aim of this study was to use c-fos like immunohistochemistry (Fos-LI) to map the trigeminal brainstem complex after intravitreal microinjection or ocular surface application of capsaicin, a selective transient receptor potential vanilloid 1 (TRPV1) agonist in male rats under barbiturate anesthesia. The effect of ocular inflammation on Fos-LI was tested 2 or 7 days after UV irradiation of the eye. In non-inflamed controls, intravitreal capsaicin produced peaks of Fos-LI at the trigeminal subnucleus interpolaris/caudalis (Vi/Vcvl) transition and in superficial laminae at the caudalis/upper cervical cord (Vc/C1) junction regions. At the Vc/C1 junction intravitreal capsaicin induced Fos-LI in a dose-dependent manner, while at the Vi/Vcvl transition responses were similar after vehicle or capsaicin injections. Two days, but not 7 days, after UV irradiation intravitreal and ocular surface capsaicin-evoked Fos-LI at the Vc/C1 junction and nucleus tractus solitarius (NTS) were markedly enhanced, whereas the responses at the Vi/Vcvl transition were not different from non-inflamed controls. More than 80% of trigeminal ganglion neurons labeled after intravitreal microinjection of Fluorogold also expressed immunoreactivity for the TRPV1 receptor. These findings suggested that most intraocular trigeminal sensory nerves serve as nociceptors. The similar pattern and magnitude of Fos-LI after capsaicin suggested that TRPV1-responsive trigeminal nerves that supply intraocular and ocular surface tissues form a unified integrative circuit in the caudal brainstem. Intensity coding of capsaicin concentration and facilitation of Fos-LI expression after UV irradiation strongly supported the hypothesis that the Vc/C1 junction was critical for nociceptive processing related to ocular pain, whereas the Vi/Vcvl transition region likely served other functions in ocular homeostasis under naïve and inflamed conditions. PMID:20643195

Chang, Z; Okamoto, K; Tashiro, A; Bereiter, D A

2010-07-17

315

Estimation and localization of electrical dipoles in somatosensory evoked potentials  

Microsoft Academic Search

Neuronal currents in the brain produce external magnetic fields and scalp surface potentials that can be measured using magnetoencephalography (MEG) and electroencephalography (EEG), respectively. In the context of the localization of neuronal sources, the forward problem is to determinate the potentials and magnetic fields that result from primary current sources. The inverse problem is to estimate the location of these

Pablo Lecumberri; M. Gomez; A. Malanda; J. Artieda; M. Alegre; I. G. de Gurtubay; M. Valencia; M. Colino

2002-01-01

316

Pattern-reversal visual-evoked potentials in children with migraine and other primary headache: evidence for maturation disorder?  

Microsoft Academic Search

Recently, evidence for a disturbed maturation of cerebral information processing in migraine came from studies investigating the auditory-evoked contingent negative variation and the auditory-evoked potential from childhood to adulthood. This study is to clarify whether age-dependent development is altered also for the processing of visual stimuli in migraine. Components of pattern-reversal visual-evoked potentials at four different spatial frequencies (which can

Rieke Oelkers-Ax; Stephan Bender; Ulrike Just; Ute Pfüller; Peter Parzer; Franz Resch; Matthias Weisbrod

2004-01-01

317

C-Fos-like immunoreactivity in the cat brainstem evoked by sneeze-inducing air puff stimulation of the nasal mucosa  

Microsoft Academic Search

Sneeze is one of the most important protective reflex of the respiratory tract. It is elicited from trigeminal peripheral fields and results in major changes in the discharge patterns of the medullary respiratory-related neurons. The pattern of c-Fos-like immunoreactivity evoked by sneezing was explored as a structural approach to the networks involved in this particular model of trigemino-respiratory interactions. Sneezes

Fabrice Wallois; Françoise Gros; Kamel Masmoudi; Nicole Larnicol

1995-01-01

318

Event-Related Evoked Potential P300 in Frontotemporal Dementia  

Microsoft Academic Search

There are no studies on event-related cognitive potentials in frontotemporal dementia (FTD). In order to evaluate the aptitude and usefulness of the event-related P300 potential in this disease, we prospectively examined 60 cases: 11 patients with FTD diagnosed according to the Lund and Manchester criteria and Neary consensus criteria, 33 patients with a probable Alzheimer’s disease diagnosis following NINCDS-ADRDA criteria,

A. Jiménez-Escrig; J. Fernandez-Lorente; A. Herrero; M. Baron; M. Lousa; G. de Blas; J. Gobernado

2002-01-01

319

Potential application of ocular and cervical vestibular-evoked myogenic potentials in Meniere's disease: a review.  

PubMed

By stimulating the ear with air-conducted sound or bone-conducted vibration stimuli, vestibular-evoked myogenic potential (VEMP) can be recorded on the contracted neck muscles, termed cervical VEMP (cVEMP), and on the extraocular muscles, termed ocular VEMP (oVEMP). These two electrophysiological tests expand the test battery for clinicians to explore the dynamic otolithic function, adding a potential usefulness to the sacculocollic reflex and vestibulo-ocular reflex, respectively. The inner ear test battery, including audiometry, and cVEMP, oVEMP and caloric tests, is designed for complete evaluation of the inner ear function, namely, the cochlea, saccule, utricle, and semicircular canals, respectively. Using this test battery to study the localization and prevalence of hydrops formation reveals that the declining function in the cochlea, saccule, utricle, and semicircular canals mimics the declining sequence of hydrops formation in temporal bone studies. This study reviewed the physiological results in Meniere's patients via the inner ear test battery, especially the potential application of the oVEMP and cVEMP tests, to correlate with the histopathological findings of Meniere's disease. PMID:23070719

Young, Yi-Ho

2012-10-15

320

Unaltered respiratory-related evoked potentials after acute diaphragm dysfunction in humans.  

PubMed

Respiratory muscles play an important role in the origin of respiratory sensations. Data dissecting the role of the diaphragm and other inspiratory muscles are scarce. This study aimed to determine the impact of diaphragm dysfunction following inspiratory resistive loading on respiratory-related evoked potentials considered as a neurophysiological substrate of certain types of respiratory sensations. Altogether, nine subjects aged 25-50 yrs (six females) participated in the study. Transdiaphragmatic pressure output of cervical magnetic stimulation (with subdivision in oesophageal and gastric component), and respiratory-related evoked potentials (C3 and C4 derivations in the international 10-20 system) following mid-inspiratory occlusions were studied before and after an inspiratory-resistive loading challenge. Predominant diaphragm dysfunction was observed in seven subjects (average 28% reduction in transdiaphragmatic pressure, from 27.25-19.91 cmH2O, with increased oesophageal-to-gastric pressure ratio). The latencies and amplitudes of all the components of the respiratory-related evoked potentials were unchanged. The study concluded that predominant diaphragm fatigue does not affect respiratory-related evoked potentials. PMID:14582915

Bezzi, M; Donzel-Raynaud, C; Straus, C; Tantucci, C; Zelter, M; Derenne, J P; Similowski, T

2003-10-01

321

Cerebral information processing in personality disorders: I. Intensity dependence of auditory evoked potentials  

Microsoft Academic Search

Patients with personality disorders such as the histrionic type exaggerate their responses when receiving external social or environmental stimuli. We speculated that they might also show an augmenting pattern of the auditory evoked potential N1–P2 component in response to stimuli with increasing levels of intensity, a response pattern that is thought to be inversely correlated with cerebral serotonin (5-HT) activity.

Wei Wang; Yehan Wang; Xianming Fu; Jianhui Liu; Chengsen He; Yi Dong; W. John Livesley; Kerry L. Jang

2006-01-01

322

Association between interoception and empathy: Evidence from heartbeat-evoked brain potential  

Microsoft Academic Search

Physiological bodily states play an important role in affective experiences. This study investigated whether the neural processing of internal body state (interoception) is associated with empathy, the understanding of the affective states of others. We used the ‘heartbeat-evoked potential’ (HEP), a surface electroencephalography (EEG) pattern, as a neural index of interoceptive processing. The HEP is contingent on the most prominent

Hirokata Fukushima; Yuri Terasawa; Satoshi Umeda

2011-01-01

323

PEAK N160 OF RAT FLASH EVOKED POTENTIAL: DOES IT REFLECT HABITUATION OR SENSITIZATION?  

EPA Science Inventory

Flash evoked potentials recorded from awake rats contain a negative peak occurring about 160 msec after the flash (N160). This peak has been associated with a specific level of arousal, and/or habituation by various authors. The current studies attempted to determine whether chan...

324

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

PubMed

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. PMID:21095851

Ellingson, Roger M; Oken, Barry

2010-01-01

325

Seeing the pain of others while being in pain: A laser-evoked potentials study  

Microsoft Academic Search

Seeing actions, emotions and feelings of other individuals may activate resonant mechanisms that allow the empathic understanding of others’ states. Being crucial for implementing pro-social behaviors, empathy is considered as inherently altruistic. Here we explored whether the personal experience of pain make individuals less inclined to share others’ pain. We used laser-evoked potentials (LEPs) to explore whether observation of painful

Massimiliano Valeriani; Viviana Betti; Domenica Le Pera; Liala De Armas; Roberto Miliucci; Domenico Restuccia; Alessio Avenanti; Salvatore Maria Aglioti

2008-01-01

326

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

327

INVESTIGATIONS OF AMITRAZ NEUROTOXICITY IN RATS. 2. EFFECTS ON VISUAL EVOKED POTENTIALS  

EPA Science Inventory

Investigations of amitraz neurotoxicity in rats. II. Effects on visual evoked potentials. Boyes, W.K. and Moser, V.C. (1986) Fundam. Appl. Toxicol. 00,000-000. As a part of a series of studies investigating the possible neurotoxicity of amitraz (AMZ), a formamidine pesticide, vis...

328

The hemispherical laterality of the visual evoked potentials during simple dot stimulus in normal human subjects  

Microsoft Academic Search

We studied scalp visual evoked potentials (VEPs) during a simple visual attention paradigm using a dot stimulus, which was presented every 1600 ms, at the center of a screen. The visual attention paradigm consisted of three tasks: task R, task L and task N. The subjects were instructed to press a button either with the right hand (task R) or

Shu Omoto; Yoshiyuki Kuroiwa; Mei Li; Toshiaki Kamitani

2000-01-01

329

Comparison of Single-Subject and Traditional Statistical Designs in Steady-State Evoked Potential Research.  

National Technical Information Service (NTIS)

An experiment was conducted to assess the relationship between level of auditory noise and a measure derived from the steady-state evoked potential (SSEP) called relative transmission time (RTT). The visual stimulus consisted of a 150-fL light that was mo...

D. R. Eddy S. L. Moise

1985-01-01

330

Evoked potentials and quantitative thermal testing in spinal cord injury patients with chronic neuropathic pain  

Microsoft Academic Search

ObjectiveNeuropathic pain (NP) is a common symptom following spinal cord injury (SCI). NP may be associated with altered processing of somatosensory pathways in dermatomes rostral to the injury level. To explore this possibility, the characteristics of contact heat evoked potentials (CHEPs) and quantitative thermal testing (QTT) were studied at and above the lesion level in SCI patients with NP. The

Hatice Kumru; Dolors Soler; Joan Vidal; Josep Maria Tormos; Alvaro Pascual-Leone; Josep Valls-Sole

331

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

Microsoft Academic Search

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 A?-innervated AMH

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

2005-01-01

332

Vestibular-evoked myogenic potentials in two patients with Ramsay Hunt syndrome  

Microsoft Academic Search

We report on the function of the inferior vestibular nerve, as monitored by the vestibular-evoked myogenic potentials (VEMP), in two patients suffering from Ramsay Hunt syndrome. Both the patients presented canal paresis (CP) and hearing loss, but in one patient normal VEMP was recorded while the other presented vagus nerve paralysis plus no VEMP response at the highest stimulus intensity

Susumu Saito; Kentaro Ochi; Takehiko Kobayashi; Natsuki Sugiura; Yasushi Komatsuzaki; Toru Ohashi

2003-01-01

333

Radiation-induced otitis media—study of a new test, vestibular-evoked myogenic potential  

Microsoft Academic Search

PurposeExcluding the radiation history, current physical examination and audiovestibular function tests fail to differentiate radiation-induced otitis media (ROM) from chronic otitis media (COM). This study applied the newly developed vestibular-evoked myogenic potential (VEMP) test to investigate whether the VEMP test can be of help in differentiating between them.

Tsung-Lin Yang; Yi-Ho Young

2004-01-01

334

Vestibular Evoked Myogenic Potentials in Deaf and Hard of Hearing Subjects  

Microsoft Academic Search

Preliminary findings conducted at the Gallaudet Hearing and Balance Center corroborate clinical findings reported in the literature indicating that in subjects with vertigo or imbalance or history of these disorders vestibular evoked myogenic potentials (VEMPs) tend to be abnormal with respect to amplitude, latency and\\/or augmented calculations. Further, the findings suggest that subjects with vertigo or imbalance may be tested

R. Steven Ackley; Chizuko Tamaki; Danielle Inverso

335

Ocular vestibular-evoked myogenic potentials in children using air conducted sound stimulation  

Microsoft Academic Search

ObjectiveThis study compared ocular vestibular-evoked myogenic potentials (oVEMPs) in children and adults using air conducted sound stimulation to determine when oVEMP characteristic parameters in children reach adult levels. The relationships between oVEMP characteristics and structural factors were also investigated.

Ying-Shuo Hsu; Shou-Jen Wang; Yi-Ho Young

2009-01-01

336

The effect of sternocleidomastoeid electrode location on vestibular evoked myogenic potential  

Microsoft Academic Search

Objective: The purpose of this study was to investigate the effect of a sternocleidomastoeid (SCM) electrode array on the vestibular evoked myogenic potential (VEMP) and the most optimal recording site for clinical use. Methods: Fifteen normal adults (10 men and 5 women, aged 18 to 38 years) were tested. We placed electrodes at four different locations over the SCM muscle:

K. ianoush Sheykholeslami; T. oshihisa Murofushi; Kimitaka Kaga

2001-01-01

337

Could vestibular evoked myogenic potentials (VEMPs) also be useful in the diagnosis of perilymphatic fistula?  

Microsoft Academic Search

The role of vestibular evoked myogenic potentials (VEMPs) is at this time indisputable in the study of vestibular disorders. Furthermore, VEMPs are widely accepted as a diagnostic tool when a superior semicircular canal dehiscence (SCD) is suspected, presenting in such cases a lowering of threshold values able to raise a recordable response due to increased inner ear immittance. According to

Giovanni Carlo Modugno; Giorgio Magnani; Cristina Brandolini; Gabriella Savastio; Antonio Pirodda

2006-01-01

338

Cervical and ocular vestibular-evoked myogenic potentials in acute vestibular neuritis  

Microsoft Academic Search

ObjectivesTo clarify the origin and afferent pathways of short-latency ocular vestibular-evoked myogenic potential (oVEMP) in response to air-conducted sound (ACS), we evaluated cervical (cVEMP) and ocular VEMPs in patients with vestibular neuritis (VN).

Byoung-Soo Shin; Sun-Young Oh; Ji Soo Kim; Tae-Woo Kim; Man-Wook Seo; Hyung Lee; Young-Ae Park

339

Ocular vestibular evoked myogenic potentials (OVEMPs) produced by impulsive transmastoid accelerations  

Microsoft Academic Search

ObjectiveRecent work has demonstrated the existence of ocular vestibular evoked myogenic potentials (OVEMPs), which likely reflect projections underlying the translational vestibular ocular reflex (TVOR). We examined extraocular muscle activity associated with impulsive acceleration of the head in the transmastoid plane.

Neil P. M. Todd; Sally M. Rosengren; James G. Colebatch

2008-01-01

340

Vestibular evoked myogenic potential (VEMP) in patients with Meniere's disease with drop attacks  

Microsoft Academic Search

Objective. In this retrospective study, we tested the hypothesis that vestibular evoked myogenic potential (VEMP) thresholds are more often elevated or absent in patients with Meniere's disease experiencing Tumarkin drop attacks than in other patients with Meniere's disease. Methods: Subjects included normal subjects (n = 14) and patients with unilateral Meniere's disease by AAO-HNS (1995) diagnostic criteria with (n =

Ferdinand C. A. Timmer; Guangwei Zhou; John J. Guinan; Sharon G. Kujawa; Barbara S. Herrmann; Steven D. Rauch

2006-01-01

341

Effect of gender on ocular vestibular-evoked myogenic potentials via various stimulation modes  

Microsoft Academic Search

ObjectiveThis study compared the characteristic parameters of ocular vestibular-evoked myogenic potentials (oVEMPs) via air-conducted sound (ACS), bone-conducted vibration (BCV), and galvanic vestibular stimulation (GVS) modes between male and female adults to determine whether gender affects oVEMPs.

Po-Hsien Sung; Po-Wen Cheng; Yi-Ho Young

2011-01-01

342

Acoustic, mechanical and galvanic stimulation modes elicit ocular vestibular-evoked myogenic potentials  

Microsoft Academic Search

ObjectiveThis study compared the characteristic parameters of ocular vestibular-evoked myogenic potentials (oVEMPs) elicited by the air-conducted sound (ACS) and bone-conducted vibration (BCV) stimulation modes as well as the galvanic vestibular stimulation (GVS) mode.

Po-Wen Cheng; Chien-Cheng Chen; Shou-Jen Wang; Yi-Ho Young

2009-01-01

343

Vestibular evoked myogenic potentials in benign paroxysmal positional vertigo and Meniere’s disease  

Microsoft Academic Search

The objective was to investigate vestibular evoked myogenic potentials (VEMP) in benign paroxysmal positional vertigo (BPPV) and Meniere’s disease, and to determine if this type of testing is valuable for assessing the vestibular system. A prospective controlled clinical study was designed in a tertiary referral center setting. The 62 participants included 17 healthy controls and 45 other subjects selected from

Güzin Akkuzu; Babur Akkuzu; Levent N. Ozluoglu

2006-01-01

344

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

ERIC Educational Resources Information Center

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…

Bates, Tim; And Others

1995-01-01

345

Multiple Channel Detection of Steady-State Visual Evoked Potentials for Brain-Computer Interfaces  

Microsoft Academic Search

In this paper, novel methods for detecting steady-state visual evoked potentials using multiple electroencephalogram (EEG) signals are presented. The methods are tailored for brain-computer interfacing, where fast and accurate detection is of vital importance for achieving high information transfer rates. High detection accuracy using short time segments is obtained by finding combinations of electrode signals that cancel strong interference signals

Ola Friman; Ivan Volosyak; Axel Graser

2007-01-01

346

Topographic mapping of cortical potentials evoked by distension of the human proximal and distal oesophagus  

Microsoft Academic Search

We describe cortical potentials evoked by balloon distension of the proximal and distal oesophagus in 8 healthy right handed volunteers. Oesophageal stimulation was performed using a pump which rapidly inflated a 2 cm silicone balloon positioned either 3 cm distal to the upper oesophageal sphincter or 5 cm proximal to the lower oesophageal sphincter, at a frequency of 0.2 Hz,

Q. Aziz; P. L. Furlong; J. Barlow; A. Hobson; S. Alani; J. Bancewicz; M. Ribbands; G. F. A. Harding; D. G. Thompson

1995-01-01

347

Response of Brain Waves to Periodic Flicker Stimuli - Entrainment and Steady-State Visually Evoked Potentials  

Microsoft Academic Search

Spatiotemporal phase dynamics of response of brain waves to periodic flicker stimuli are investigated to compare the response properties of the alpha waves with those of steady-state visually evoked potentials (SSVEPs). Under flicker stimuli the frequency of which is outside the range 8-13 Hz (outside the range of the alpha wave), the response of the brain wave, namely, the SSVEPs,

S. Nishifuji; S. Tanaka

2006-01-01

348

Comparing the habituation of late auditory evoked potentials to loud and soft sound  

Microsoft Academic Search

The objective fitting of hearing aids and cochlear implants remains a challenge. In particular, the determination of whether sound is perceived as too loud or comfortable represents an unsolved problem in noncooperative patients. In a first step of an ongoing study, we assess the feasibility of habituation correlates in late auditory evoked potentials (LAEPs) to discriminate between a soft sound

Mai Mariam; Wolfgang Delb; Farah I. Corona-Strauss; Marc Bloching; Daniel J. Strauss

2009-01-01

349

Heterotopic painful stimulation decreases the late component of somatosensory evoked potentials induced by electrical tooth stimulation  

Microsoft Academic Search

The purpose of this study was to determine the relationship between the late component of somatosensory evoked potentials (SEP) induced by electrical tooth stimulation and subjective pain estimation when heterotopically painful stimulation was delivered to humans. The noxious electrical conditioning stimuli were applied to the left median nerve in noxious session I and the right median nerve in noxious session

Katsunori Motohashi; Masahiro Umino

2001-01-01

350

Noise Reduction in Brain Evoked Potentials Based on Third-Order Correlations  

Microsoft Academic Search

In this paper, we use third-order correlations (TOC) in developing a filtering technique for the recovery of brain evoked potentials (EPs). The main idea behind the presented technique is to pass the noisy signal through a finite impulse response filter whose impulse response is matched with the shape of the noise-free signal. It is shown that it is possible to

R. R. Gharieb; Andrzej Cichocki

2001-01-01

351

Noise reduction in brain evoked potentials based on third-order correlations  

Microsoft Academic Search

We use third-order correlations (TOC) in developing a filtering technique for the recovery of brain evoked potentials (EPs). The main idea behind the presented technique is to pass the noisy signal through a finite impulse response filter whose impulse response is matched with the shape of the noise-free signal. It is shown that it is possible to estimate the filter

R. R. Gharieb; A. Cichocki

2001-01-01

352

Dermatomal somatosensory evoked potential demonstration of nerve root decompression after VAX-D therapy  

Microsoft Academic Search

Reductions in low back pain and referred leg pain associated with a diagnosis of herniated disc, degenerative disc disease or facet syndrome have previously been reported after treatment with a VAX-D table, which intermittently distracts the spine. The object of this study was to use dermatomal somatosensory evoked potentials (DSSEPs) to demonstrate lumbar root decompression following VAX-D therapy. Seven consecutive

William K. Naguszewski; Robert K. Naguszewski; Earl E. Gose

2001-01-01

353

The Use of Motor Evoked Potentials in the Diagnosis of Psychogenic Quadriparesis  

Microsoft Academic Search

We present a case illustrating the usefulness of motor evoked potentials (MEPs) in differentiating psychogenic from organic postoperative paralysis. Discussed is a 12-year-old girl who underwent surgery for the repair of a recurrent syringomyelia. On the 6 day after a proximal revision of her syringoperitoneal shunt she returned to the hospital with deep quadriparesis, bowel and bladder incontinence, and complaining

Nobuhito Morota; Vedran Deletis; Kiril Kiprovski; Fred Epstein; Rick Abbott

1994-01-01

354

Visually evoked cortical potentials in the evaluation of homonymous and bitemporal visual field defects  

Microsoft Academic Search

Visually evoked cortical potentials were studied in six patients with a homonymous and six with a bitemporal hemianopia by presenting a pattern-reversal stimulus separately to a temporal or nasal retinal area and by recording the responses from leads over the hemispheres. Homonymous visual field defects are characterized by a reduction of VECPs from the affected hemisphere. The disturbance of VECPs

H. G. Wildberger; G. H. Van Lith; R. Wijngaarde; G. T. Mak

1976-01-01

355

The use of anesthesia during evoked potential audiometry in goldfish (Carassius auratus)  

PubMed Central

Auditory evoked potentials (AEPs) have become a widely utilized measure of hearing sensitivity. Most investigators use pharmacological paralysis to reduce myogenic noise and immobilize the animal for stable electrical recordings, but additional anesthesia is generally not used because the most commonly available fish anesthetic, the cholinergic antagonist tricane methanosulfate (MS222), is known to disrupt hair cell and primary afferent physiology. Anesthetic agents that do not interfere with auditory function would be a useful adjunctant to paralytic immobilization and would reduce any possible distress incurred by prolonged immobilization. In this report we tested the opiate anesthetic Fentanyl and compared hearing thresholds in immobilized versus immobilized and anesthetized animals. Short-term effects of mild MS222 anesthesia were also measured via evoked potential audiometry. Animals were tested before and after Fentanyl injection (100, 500 and 2500 ?g g?1 fish body-weight) using standard evoked potential audiometry. Tone pips, 0.2 to 3 kHz, from an aerial loudspeaker served as stimuli. Fentanyl altered evoked potential waveforms slightly, but did not alter estimated threshold sensitivity. These results suggest Fentanyl be considered as a possible addition to AEP techniques in goldfish (Carassius auratus) and poikilothermic vertebrates generally.

Cordova, Micah S.; Braun, Christopher B.

2007-01-01

356

Tethered cord after spina bifida aperta: a longitudinal study of somatosensory evoked potentials  

Microsoft Academic Search

Progressive neurological deterioration may occur after meningomyelocele repair. Magnetic resonance imaging almost invariably demonstrates a conus medullaris in an abnormally low position, whether neurological symptoms develop or not. Surgery of a secondary tethered cord is indicated when progression of neurological symptoms is documented. We performed a longitudinal study of posterior tibial nerve somatosensory evoked potentials (SSEPs) in children and adolescents

R. Boor; M. Schwarz; B. Reitter; D. Voth

1993-01-01

357

A Steady State Visually Evoked Potential Investigation of Memory and Ageing  

ERIC Educational Resources Information Center

|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…

Macpherson, Helen; Pipingas, Andrew; Silberstein, Richard

2009-01-01

358

Laboratory Note: Effect on Sleep Latency of Pre-Sleep AEP (Auditory Evoked Potential) Procedures.  

National Technical Information Service (NTIS)

In a 12-night study of the effects of 1-tryptophan in poor sleepers, waking auditory evoked potentials (AEPs) were obtained prior to lights out on the third placebo-baseline night and fifth treatment night. Sleep latencies were significantly shorter on bo...

C. L. Spinweber

1984-01-01

359

Enhancement of Neuroplastic P2 and N1c Auditory Evoked Potentials in Musicians  

Microsoft Academic Search

P2 and N1c components of the auditory evoked potential (AEP) have been shown to be sensitive to remodeling of the auditory cortex by training at pitch discrimination in nonmusician subjects. Here, we investigated whether these neuroplastic components of the AEP are enhanced in musicians in accordance with their musical training histories. Highly skilled violinists and pianists and nonmusician controls listened

Antoine Shahin; Daniel J. Bosnyak; Laurel J. Trainor; Larry E. Roberts

2003-01-01

360

Scalp topography and analysis of intracranial sources of face-evoked potentials  

Microsoft Academic Search

Several reports have described that a positive vertex peak of an evoked potential varied in amplitude and latency specifically when images of faces were the eliciting stimulus. The scalp topography and the possible underlying dipole sources of this peak are the subject of this report. We presented black-and-white photographs of human faces, flowers and leaves to 16 healthy subjects and

Kai Bötzel; Stefan Schulze; Stefan R. G. Stodieck

1995-01-01

361

Evoked potentials elicited on the cerebellar cortex by electrical stimulation of the rat spinocerebellar tract  

Microsoft Academic Search

BackgroundIn the current study, as a first step to develop a monitoring method of cerebellar functions, we tried to record evoked potentials on the cerebellar cortex by electrical stimulation of the rat SCT, which is located in the Inf-CPed.

Hiroyuki Muramatsu; Kyouichi Suzuki; Tatsuya Sasaki; Masato Matsumoto; Jun Sakuma; Masahiro Oinuma; Takeshi Itakura; Namio Kodama

2009-01-01

362

Serial Visual Evoked Potentials in 90 Untreated Patients With Acute Optic Neuritis  

Microsoft Academic Search

To establish the value of visual evoked potentials (VEPs) for monitoring disease evolution, we undertook a population-based study of 90 untreated patients 12 to 57 years of age (median, 32 years) at the onset of optic neuritis (ON) and after 2, 4, 12, and 52 weeks. Optic neuritis was monosymptomatic (AMON) in 58 patients and part of the clinically definite

Jette Lautrup Frederiksen; Jorge Petrera

1999-01-01

363

Laser-evoked cerebral potentials and sensory function in patients with central pain  

Microsoft Academic Search

Central pain syndromes (CPS) could be caused by disinhibition of spinothalamic excitability or by other central nervous system (CNS) changes caused by reduced spinothalamic function. To examine these possibilities, we studied 11 patients (ages 51–82 years) with unilateral central pain and with reproducible cerebral evoked vertex potentials in response to cutaneous stimulation of the normal side with pulses from an

K. L. Casey; A. Beydoun; J. Boivie; B. Sjolund; H. Holmgren; G. Leijon; T. J. Morrow; I. Rosen

1996-01-01

364

Inhibition of cortical evoked potentials and sensation by self-initiated movement in man  

Microsoft Academic Search

AN imposed, passive or externally paced displacement (EPD) of the index finger in man evokes brain potentials that differ in delay and waveform for postcentral, precentral and prefrental areas1. Displacement so imposed leads to less accurate subjective estimation of limb position from that obtained by self initiated movement2. This behavioural observation as far as we know has not been neurophysiologically

D. Papakostopoulos; R. Cooper; H. J. Crow

1975-01-01

365

Proprioceptive modulation of somatosensory evoked potentials during active or passive finger movements in man  

Microsoft Academic Search

The effects of active and passive finger movements on somatosensory potentials evoked by stimulation of the median nerve at the wrist or of finger I were investigated in 15 healthy volunteers. As compared to the resting condition, both active and passive movements of the stimulated hand fingers induced a marked reduction in the amplitude of the primary cerebral response (N20-P25

G Abbruzzese; S Ratto; E Favale; M Abbruzzese

1981-01-01

366

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

ERIC Educational Resources Information Center

|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…

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

2010-01-01

367

Evoked potentials for the prediction of vegetative state in the acute stage of coma  

Microsoft Academic Search

For comatose patients in intensive care units, it is important to anticipate their functional outcome as soon and as reliably as possible. Among clinical variables the Glasgow Coma Score (GCS) and the patient's pupil reactivity are the strongest predictive variables. Evoked potentials help to assess objectively brain function. Over the past 20 years, numerous studies have assessed their prognostic utility

Catherine Fischer; Jacques Luauté

2005-01-01

368

Development of directional motion symmetry in the monocular visually evoked potential of infant monkeys  

Microsoft Academic Search

Motion processing in humans and monkeys exhibit a directional asymmetry during infancy which is not present in adults except following abnormal visual rearing conditions. To characterize the time course for maturation of a symmetric response, we measured the monocular visually evoked potential (MVEP) response to 0.26 c\\/deg gratings oscillating horizontally at 6 Hz in 13 infant rhesus monkeys between 1

Rick J. Brown; James R. Wilson; Anthony M. Norcia; Ronald G. Boothe

1998-01-01

369

DESIGN AND DEVELOPMENT OF VISUAL EVOKED POTENTIALS RECORDING SYSTEM FOR DIAGNOSIS OF OPTIC NERVE DISEASES  

Microsoft Academic Search

This paper deals with the design and development of a Visual Evoked Potentials (VEPs) recording system for the diagnosis of optic nerve diseases. In this system visual stimulator, electrodes, surge protection circuit, pre-amplifier, filter network, post amplifier, isolation circuit and A\\/D converter have been used as building blocks to acquire VEPs. After proper signal processing, the amplitude between the first

G. B. Mukartihal; S. Radhakrishnan; S. S. K. Ayyar

370

Dynamic topography of pattern visual evoked potentials (PVEP) in psychogenic visual loss patients  

Microsoft Academic Search

We investigated to measure the objective visual acuity using pattern visual evoked potentials (PVEP) to help the diagnosis with psychogenic visual loss (PVL) who ranged in age from 7 to 14 years old. Pattern stimuli consisted of black and white checkerboard patterns (39, 26, 15 and 9') with a visual angle of 8 degrees and a contrast level of 15%.

A. Nakamura; A. Tabuchi; E. Matsuda; W. Yamaguchi

2000-01-01

371

Alterations in Transient Visual-Evoked Potentials Induced by Clonazepam and Sodium Valproate  

Microsoft Academic Search

The transient visual-evoked potentials (VEP), recorded in patients suffering from generalized epilepsy, can be characterized by a duplication of the negative peak with a latency of 70–100 ms, a strong increase in amplitude of the negative peak between 80 and 130 ms and the development of a high amplitude slow negative wave following the primary complex. In this study we

A. C. Declerck; L. T. Oei; W. Arnoldussen; M. te Dorsthorst

1985-01-01

372

Deficits in the visual evoked potentials of cats as a result of visual deprivation  

Microsoft Academic Search

Summary Visual evoked potentials in response to contrast reversal of grating patterns were used as a measure of visual function in normal and visually deprived cats. In cats which had been dark reared from birth (BD cats) there was a characteristic change in VEP waveform from normal, for both eyes and for all spatial frequencies of testing stimulus. In cats

A. Snyder; R. Shapley

1979-01-01

373

Development of a steady state visual evoked potential (SSVEP)-based brain computer interface (BCI) system  

Microsoft Academic Search

This paper describes the development of a synchronous, online brain computer interface (BCI) system based on detecting the steady-state visual evoked potential (SSVEP). The system includes a programmable visual stimulator, EEG amplifier with filter system, data acquisition card, and signal processing and classification algorithms. Two types of experiments were carried out; training experiments were conducted to determine three optimal frequencies

R. S. a Leow; F. a Ibrahim; M.b Moghavvemi

2007-01-01

374

Novel protocol for random visual stimulation during visual evoked potential testing  

Microsoft Academic Search

The standard method of studying the visual evoked potentials (VEPs) of multiple visual stimuli is to separately record the VEP for each stimulus then compare the resultant signals. The resultant signals are subject to inter-presentation noise factors. These can include subject attention, electrode noise and subject movement. We have developed a technique, which allows all of the visual stimuli to

P. J. Wojnicki; E. Uyeda; E. Micheli-Tzanakou

2003-01-01

375

Methods of visual acuity determination with the spatial frequency sweep visual evoked potential  

Microsoft Academic Search

Purpose: The spatial frequency sweep visual evoked potential (sVEP) is used to rapidly determine visual acuity in children or non-responsive patients. Two techniques have been used to separate signal from noise: (1) the 95% confidence interval for the signal amplitude (95% CI) or (2) the amplitude of a Fourier frequency adjacent to 2· the signal frequency (DFT). The purpose of

William H. Ridder

2004-01-01

376

Alteration of the visual evoked potential by macular holes: Comparison with optic neuritis  

Microsoft Academic Search

Nine patients with maculopathy (macular holes, macular cysts, and lamellar holes) and ten patients with optic neuritis were examined in order to determine changes in the visual evoked potential (VEP) in response to pattern-reversal stimulation. Eyes with lamellar holes had normal P100 latency, but eyes with macular cysts and macular holes had prolonged P100 latency. Eyes with optic neuritis exhibited

L. N. Johnson; R. D. Yee; R. S. Hepler; D. A. Martin

1987-01-01

377

Visual evoked potentials in phenylketonuria: association with brain MRI, dietary state, and IQ  

Microsoft Academic Search

At separate institutions, pattern reversal visual evoked potentials (VEPs) were recorded in children and older patients with phenylketonuria and compared with MRI of the brain. In nine patients aged less than 14 years, who were still on a diet low in phenylalanine, VEPs were clearly abnormal in only one and the abnormalities seen on MRI were mild. In 27 patients

S J Jones; G Turano; A Kriss; F Shawkat; B Kendall; A J Thompson

1995-01-01

378

A personal computer-based visual evoked potential stimulus and recording system  

Microsoft Academic Search

A system for recording electroretinograms and visual evoked cortical potentials has been constructed with the use of a personal computer and a digital signal processing card. The system is based on widely available commercial hardware. It has been designed to be capable of performing routine visual electrophysiology as well as allowing the development of novel visual stimuli and signal detection

Michael S. Bradnam; Aled L. Evans; Donald M. I. Montgomery; David Keating; Bertil E. Damato; Alice Cluckie; Donald Allan

1994-01-01

379

Cholinergic Pairing with Visual Activation Results in Long-Term Enhancement of Visual Evoked Potentials  

Microsoft Academic Search

Acetylcholine (ACh) contributes to learning processes by modulating cortical plasticity in terms of intensity of neuronal activity and selectivity properties of cortical neurons. However, it is not known if ACh induces long term effects within the primary visual cortex (V1) that could sustain visual learning mechanisms. In the present study we analyzed visual evoked potentials (VEPs) in V1 of rats

Jun Il Kang; Elvire Vaucher; Teresa Serrano-Gotarredona

2009-01-01

380

Effect of body temperature on visual evoked potential delay and visual perception in multiple sclerosis  

Microsoft Academic Search

Seven multiple sclerosis patients were cooled and four heated, but evoked potential delay changed in only five out 11 experiments. Control limits were set by cooling eight and heating four control subjects. One patient gave anomalous results in that although heating degraded perceptual delay and visual acuity, and depressed the sine wave grating MTF, double-flash resolution was improved. An explanation

D Regan; T J Murray; R Silver

1977-01-01

381

Circadian and hypothermia-induced effects on visual and auditory evoked potentials in multiple sclerosis  

Microsoft Academic Search

Objectives: Body cooling has been proposed as a symptomatic treatment for multiple sclerosis. This study aimed to assess the effects of body cooling and of circadian variations on clinical parameters and on visual and auditory evoked potential measures in multiple sclerosis patients.Methods: Clinical status was assessed and VEPs, BAEPs and MLAEPs (all with two stimulus frequencies) were recorded a total

A Romani; R Bergamaschi; M Versino; A Zilioli; R Callieco; V Cosi

2000-01-01

382

Somatosensory evoked potential monitoring of lumbar pedicle screw placement for in situ posterior spinal fusion  

Microsoft Academic Search

BACKGROUND CONTEXT: Somatosensory evoked potentials (SSEP) are commonly used to monitor the spinal cord and nerve roots during operative procedures that put those structures at risk. The utility of SSEPs to evaluate cauda equina and nerve root function during posterior spinal arthrodesis with pedicular fixation for degenerative lumbar disease has been reported anecdotally and remains controversial.PURPOSE: An institution-wide review of

Mukund Gundanna; Mark Eskenazi; John Bendo; Jeffrey Spivak; Ronald Moskovich

2003-01-01

383

Direct comparison of two statistical methods for determination of evoked-potential thresholds  

Microsoft Academic Search

Several statistical procedures have been proposed as objective methods for determining evoked-potential thresholds. Data have been presented to support each of the methods, but there have not been direct comparisons using the same data. The goal of the present study was to evaluate correlation and variance ratio statistics using common data. A secondary goal was to evaluate the utility of

Ted L. Langford; James H. Patterson Jr.

1994-01-01

384

Real-Time Adaptive Microstimulation Increases Reliability of Electrically Evoked Cortical Potentials  

Microsoft Academic Search

Cortical neuroprostheses that employ repeated elec- trical stimulation of cortical areas with fixed stimulus parameters, are faced with the problem of large trial-by-trial variability of evoked potentials. This variability is caused by the ongoing cor- tical signal processing, but it is an unwanted phenomenon if one aims at imprinting neural activity as precisely as possible. Here, we use local field

Dominik Brugger; Sergejus Butovas; Martin Bogdan; Cornelius Schwarz

2011-01-01

385

Controlling a robot with a brain-computer interface based on steady state visual evoked potentials  

Microsoft Academic Search

In this paper a brain-computer interface (BCI) is presented which uses steady-state visual evoked potentials for controlling a robot. EEG is derived from three subjects to test the performance of the system. For feature extraction and classification on one hand the Minimum Energy method, and on the other hand the Fast Fourier Transformation (FFT) with linear discriminant analysis (LDA) is

Robert Prueckl; Christoph Guger

2010-01-01

386

Hyperalgesia or hypervigilance? An evoked potential approach to the study of fibromyalgia syndrome  

Microsoft Academic Search

Summary Past research on the phenomenon of enhanced pain sensitivity in fibromyalgia syndome (FS) revealed evidence for both a higher pain magnitude in response to nociceptive stimuli (hyperalgesia) and a general perceptual amplification of sensations (hypervigilance). In order to distinguish between these two aspects of disturbed sensory processing in FS, cerebral evoked potentials after brief painful laser and auditory stimuli

J. Lorenz

1998-01-01

387

Prognostic significance of the pattern visual evoked potential in ocular hypertension  

Microsoft Academic Search

This paper reports a prospective study on 49 ocular hypertensive patients to evaluate the prognostic significance of transient abnormalities in the pattern visual evoked potential (VEP) in the development of glaucoma. Seven of 24 patients with VEP abnormalities at diagnosis of ocular hypertension developed glaucomatous field defects in the follow-up period as compared with none of 25 patients with normal

L C Bray; K W Mitchell; J W Howe

1991-01-01

388

ALTERATIONS IN FLASH EVOKED POTENTIALS (FEPS) IN RATS PRODUCED BY 3,3'-IMINODIPROPIONITRILE (IDPN)  

EPA Science Inventory

-3,-3'-iminodiproprionitrile (IDPN) is a neurotoxicant that produces changes in flash evoked potentials (FEPs) 18 weeks after treatment (52). e examined dose and time-related effects of IDPN on FEPs at earlier time points than previously studied. dult male Long-Evans rats were gi...

389

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...

390

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

PubMed

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. PMID:12739602

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

2003-04-26

391

Study of visual evoked potentials inthe assessment of the central optic pathways in leprosypatients  

Microsoft Academic Search

\\u000a Abstract.\\u000a   We evaluated the possible involvement of central optic\\u000apathways (COP) in leprosy patients with visual evoked\\u000apotentials, an easy, sensitive and reliable noninvasive method\\u000afor evaluation of COP. In 37 patients with lepromatous leprosy\\u000aand in 37 age-matched controls, we measured reversal pattern\\u000avisual evoked potentials (RP-VEP) and nerve conduction\\u000aparameters. The mean latency value of positive peak P100

H. Ulvi; R. Yigiter; T. Yoldas; I. Erdem; B. Müngen

2003-01-01

392

Depression of evoked potentials in brain slices by adenosine compounds.  

PubMed Central

1 A study has been made of the action of adenosine on surface slices of guinea-pig olfactory cortex in vitro. 2 With extracellular recordings from the pial surface and stimulation of the presynaptic input, the lateral olfactory tract (LOT) generated a monosynaptic negative wave representing dendritic excitatory potentials. This negative wave was depressed by bath application of 1 micron adenosine with increasing effect up to 1 mM. Adenosine 5'--triphosphate (ATP), adenosine 5'-monophosphate (AMP) and cyclic adenosine 3',5'-monophosphate (cyclic AMP) had similar depressant actions. Adenine and guanosine were very weak depressants. 3 Theophylline concentrations in the range 10 micron to 3 mM progressively antagonized the action of adenosine. 4 Dibuyryl cyclic AMP (100 micron) and agents which increase intracellular cyclic AMP were not depressants, suggesting that the action of adenosine was not cyclic AMP-mediated. 5 Intracellular recordings confirmed the depressant effect of adenosine on excitatory potentials generated by LOT stimulation and also showed that postsynatpic action potentials and the membrane of the soma were unaffected by adenosine. 6 Since presynaptic action potentials were also unaffected by adenosine, these experiments suggest that adenosine reduces excitatory transmission at LOT synapses and fortifies the idea that adenosine has a 'neurohumoral' action.

Scholfield, C N

1978-01-01

393

An information flow technique for category related evoked potentials  

Microsoft Academic Search

A general mathematical technique is developed for information flow among various subsystems of a system when two or more classes of stimuli are presented to the system. The technique is validated by various simulation studies and then applied to a brain system. The usefulness of the technique is demonstrated for visual event related potentials (ERPs) obtained from human subjects suffering

R. K. Kushwaha; W. J. Williams

1992-01-01

394

Relationships between behavior, brainstem and cortical encoding of seen and heard speech in musicians and non-musicians  

Microsoft Academic Search

Musicians have a variety of perceptual and cortical specializations compared to non-musicians. Recent studies have shown that potentials evoked from primarily brainstem structures are enhanced in musi- cians, compared to non-musicians. Specifically, musicians have more robust representations of pitch peri- odicity and faster neural timing to sound onset when listening to sounds or both listening to and viewing a speaker.

Gabriella Musacchia; Dana Strait; Nina Kraus

2008-01-01

395

Trigeminal small-fibre function assessed with contact heat evoked potentials in humans.  

PubMed

Contact heat stimuli have been reported to excite mechano-thermal nociceptors and to evoke brain potentials (CHEPs) from the limbs. We investigated whether contact heat evokes reproducible CHEPs from the trigeminal territory and may prove a reliable diagnostic tool in facial neuropathic pain. We applied contact heat stimuli to the perioral and supraorbital regions; CHEPs were recorded from the vertex in 20 controls and 2 patients with facial neuropathic pains, and reflex responses from the orbicularis oculi and masticatory muscles in 5 controls. We studied the correlation between CHEP data and perceptive ratings, site of stimulation, and age. Finally, we compared CHEPs with laser evoked potentials (LEPs). Contact heat stimuli at 51 degrees C evoked vertex potentials consisting of an NP complex similar to that elicited by laser pulses, though with a latency some 100-ms longer. Perioral stimulation yielded higher pain intensity ratings, shorter latency and larger amplitude CHEPs than supraorbital stimulation. CHEP data correlated significantly with age. Contact heat stimuli at 53 degrees C evoked a blink-like response in the relaxed orbicularis oculi muscle and a silent period in the contracted masseter muscle. In patients with facial neuropathic pain the CHEP abnormalities paralleled those seen with LEPs. We were unable to achieve reproducible signals related to C-receptor stimulation by contact heat stimuli at 41 degrees C in the ten subjects in whom they were tested. Contact heat stimulation, as well as laser stimulation, easily yields large-amplitude brain potentials and nociceptive reflexes, both related to the Adelta input. However CHEPs are not suitable for C-fibres potentials recording. PMID:17346887

Truini, A; Galeotti, F; Pennisi, E; Casa, F; Biasiotta, A; Cruccu, G

2007-03-07

396

Somatosensory-evoked potentials during aortic coarctation repair  

Microsoft Academic Search

Objective: To determine the incidence of somatosensoryevoked potential (SSEP) changes and the interventions based on these changes during aortic coarctation repair.Design: Retrospective review.Setting: Single-institution, university hospital.Participants: Eighty-four children who had undergone surgical repair of aortic coarctation from January 1984 to May 1996.Interventions: SSEPs were monitored in all patients throughout the procedure. A persistent decrease in amplitude greater than 50% from

Lisa W. Faberowski; Susan Black; Mark F. Trankina; Richard J. Pollard; Rhonda K. Clark; Michael E. Mahla

1999-01-01

397

Potentiating vanadium-evoked glucose metabolism by novel hydroxamate derivatives  

Microsoft Academic Search

Summary  L-glutamic acid (?) monohydroxamate (L-Glu(?)HXM) enhances the insulinomimetic activity of vanadium ions bothin vitro andin vivo. Based on this ligand as a lead compound, and in order to delineate molecular features relevant to its anti-diabetic potential,\\u000a 14 related derivatives, including short peptides, were synthesized by solution as well as by solid phase methodologies. In\\u000a addition, hydroxamate derivatives of (+) pantothenic

Sagit Hindi; Dov P. Grossman; Itzhak Goldwaser; Yoram Shechter; Mati Fridkin

2002-01-01

398

Potentiating vanadium-evoked glucose metabolism by novel hydroxamate derivatives  

Microsoft Academic Search

L-glutamic acid (?) monohydroxamate (L-Glu(?)HXM) enhances the insulinomimetic activity of vanadium ions both in vitro and in vivo. Based on this ligand as a lead compound, and in order to delineate molecular features relevant to its anti-diabetic potential, 14 related derivatives, including short peptides, were synthesized by solution as well as by solid phase methodologies. In addition, hydroxamate derivatives of

Sagit Hindi; Dov P. Grossman; Itzhak Goldwaser; Yoram Shechter; Mati Fridkin

2002-01-01

399

Neonatal ventral hippocampal lesions modify pain perception and evoked potentials in rats.  

PubMed

This work concerns the debate surrounding the modified pain reactivity of patients with schizophrenia and other possible perceptive distortions. Rats with a neonatal ventral hippocampal lesion (NVHL) were used to model the neuro-developmental aspect of schizophrenia, and their reactivity to various stimuli was evaluated. The results could also help understand sensory deficits in other neuro-developmental disorders. Behavioural reactions to graduated painful thermal and mechanical stimuli were observed, and evoked potential responsiveness to tactile, visual and acoustic non-painful stimuli was recorded and compared to non-operated and sham lesioned controls. A higher threshold was observed with painful mechanical stimuli and shorter paw withdrawal latency with thermal stimuli. This was particularly relevant as there was no change in the evoked potentials triggered by non-nociceptive tactile stimulation of the same part of the body. There was a 10 dB(A) increase in the auditory threshold and a suppression of auditory sensory motor gating. Visually evoked potentials did not appear to be affected. Taken together, the results showed that NVHL-evoked alteration of brain development induces mechanical hypoalgesia, thermal hyperalgesia and auditory sensory changes. The data also contribute towards elucidating mechanisms underlying sensory deficits in neurodevelopmental diseases, including schizophrenia. PMID:22766216

Sandner, Guy; Meyer, Laurence; Angst, Marie-Josée; Guignard, Blandine; Guiberteau, Thierry; Mensah-Nyagan, Ayikoe Guy

2012-07-03

400

PAS-Induced Potentiation of Cortical-Evoked Activity in the Dorsolateral Prefrontal Cortex.  

PubMed

Neuroplasticity and long-term potentiation (LTP) in the dorsolateral prefrontal cortex (DLPFC) are considered important mechanisms in learning and memory, and their disruption may be related to the pathophysiology of several neuropsychiatric disorders. Paired associative stimulation (PAS) is a brain stimulation paradigm that produces enhanced activity in the human motor cortex that may be related to LTP. In a group of 15 healthy participants, we report on the potentiation of cortical-evoked activity in the human DLPFC using the combination of PAS and electroencephalography. In contrast, a PAS control condition did not result in potentiation in another group of nine healthy participants. We also demonstrate that PAS-induced potentiation of cortical-evoked activity is characterized by anatomical specificity that is largely confined to the site of stimulation. Finally, we show that PAS results in potentiation of ?- and ?-activity and ?-phase-?-amplitude coupling. These neurophysiological indices may be related to working memory, an important function of the DLPFC. To our knowledge, this is the first report of potentiation of cortical-evoked activity in the DLPFC. As this potentiation may be related to LTP, our findings provide a model through which neuroplasticity in health and disease states in the frontal cortex can be studied. PMID:23820586

Rajji, Tarek K; Sun, Yinming; Zomorrodi-Moghaddam, Reza; Farzan, Faranak; Blumberger, Daniel M; Mulsant, Benoit H; Fitzgerald, Paul B; Daskalakis, Zafiris J

2013-07-03

401

Sufentanil and nitrous oxide anaesthesia for the recording of transcranial magnetic motor evoked potentials in dogs.  

PubMed

Transcranial magnetic motor evoked potentials were recorded from the extensor carpi radialis muscle of the forelimbs and from the cranial tibial muscle of the hindlimbs of anaesthetised dogs. The dogs were premedicated with droperidol and fentanyl and a light plane of anaesthesia was induced and maintained with sufentanil and nitrous oxide. The potentials recorded under sufentanil and nitrous oxide anaesthesia were suppressed in comparison with baseline recordings under droperidol and fentanyl sedation: their latencies were significantly increased and their amplitudes significantly decreased (P < 0.05). However, the potentials could be recorded reliably in all the dogs and with very good reproducibility. This narcotic anaesthesia also allowed sensory evoked potentials to be recorded reliably. PMID:8817859

Van Ham, L M; Nijs, J; Mattheeuws, D R; Vanderstraeten, G G

1996-06-29

402

Changes in Midlatency Auditory Evoked Potentials following Two Yoga-Based Relaxation Techniques  

Microsoft Academic Search

Practicing meditation while focusing on a sound or a symbol influenced midlatency auditory evoked potentials (MLAEPs). Cyclic meditation (CM) is a technique combining yoga postures with meditation while supine, which has influenced the P300 event-related potential. The effects of CM on MLAEPs have not been previously studied.The MLAEPs were studied before and after the practice of CM compared to an

Pailoor Subramanya; Shirley Telles

2009-01-01

403

Influence of narcotics on luminance and frequency modulated visual evoked potentials in rats  

Microsoft Academic Search

Quantification of visual function is essential for the impact of disease models and their treatment. Recently, we introduced\\u000a a chronic implant model to record visual evoked potentials (VEP) in awake Brown–Norway rats. Here, we investigated the hemispheric\\u000a distribution of VEP after monocular stimulation, the chronic electrode implantation and the influence of commonly used anesthetics.\\u000a Potentials were recorded by electrodes, implanted

T. Jehle; D. Ehlken; K. Wingert; T. J. Feuerstein; M. Bach; W. A. Lagrèze

2009-01-01

404

Measurement of evoked potential in recognition of faces and buildings.  

PubMed

In the functional neuro-imaging, it is known that the activation to the second stimulus is suppressed when two stimuli are given successively with a short interval as sensory inputs. This kind of suppressive phenomenon has been observed in event-related potential (ERP) signals as well as functional MRI signals of primary auditory, somatosensory and visual cortices. However, we rarely find reports to ERP suppression in higher-order areas of the brain. In this study we used a paired stimulus paradigm. The paired stimulus paradigm consisted of successively presented two stimuli in one trial. We recorded ERP related to recognition of faces and buildings to investigate the suppressive phenomenon in higher-order areas of the brain. We used the paired stimulus paradigm which was comprised of face, building and gray-colored-plain (gray) pictures. The inter-stimulus interval of two stimuli was 200 ms. On the points of O2 and T6, we observed that the ERP for the latter stimulus (face picture) was suppressed severely when a face-gray stimulus pair was presented. On the other hand, when a gray-building stimulus pair was presented, the ERP for the latter stimulus (building picture) was not suppressed on the points of O2 and T6. The similar suppression was observed with a face-face stimulus pair. PMID:19163620

Fujiyama, Saki; Sung, Yul-Wan; Ogawa, Seiji; Hayami, Takehito; Iramina, Keiji

2008-01-01

405

[Influence of low concentrations of halogenated anesthetics on the electroretinogram and visual evoked potentials in children].  

PubMed

During anaesthesia for neurophysiological investigations, halogen anaesthetics delivered at high concentrations altered visually evoked potentials. Low concentrations of volatile anaesthetics were proposed to avoid these alterations. Thirty young children, with visual or neurological abnormalities, were divided in two groups: the first group (n = 16), mean age of 20 months, was anaesthetized with halothane 0.5%, and the second (n = 14), mean age of 14 months, with enflurane 1.5%. Retinal action potentials (RAP) and visually evoked potentials (VEP) were obtained by computerized methods. The morphology of graphs before anaesthesia and after increasing concentrations of anaesthetics were compared. Height and latencies of the principal waves were measured. Low concentrations of halothane as well as enflurane avoided RAP and VEP disturbances. Nevertheless, no statistically significant data was obtained because of individual variations due to age, pathology and technical conditions. PMID:6711925

Debrabant, F; Hache, J C; Cantineau, D; Scherpereel, P

1984-01-01

406

Late cortical auditory potentials evoked by electrostimulation in deaf and cochlear implant patients.  

PubMed

Deaf or residually hearing patients without sufficient auditory communication by conventional hearing aids are candidates for the implantation of a cochlear prosthesis. In addition to objective audiometry (electrophysiological evaluation and assessment of the degree and type of hearing loss), preoperative electrostimulation tests should be performed. In so doing, it is reasonable to employ late cortical potentials for preoperative patient selection as well as for postoperative follow-ups. In contrast to early potentials (such as, brain stem evoked potentials), late cortical potentials offer technical, physiological, medical and psychological advantages. This approach to testing has been used successfully in 70 patients (including children over the age of 3 years). PMID:1768404

Brix, R; Gedlicka, W

1991-01-01

407

Visual evoked cortical potentials and pattern electroretinograms in Parkinson's disease and control subjects.  

PubMed Central

Parkinson's disease patients have been shown to have abnormal visually evoked cortical potentials (VEPs) to pattern stimulation. Whereas dopamine is not an important neurotransmitter in the central visual pathways, the retina is rich in dopamine and, together with previous animal and human studies, this suggests that the abnormal VEPs in Parkinson's disease patients may be due to a biochemical and electrophysiological disorder in the retina. This hypothesis has been examined by studying the VEPs and pattern electroretinogram (PERG) of Parkinson's disease patients and matched control subjects. The amplitudes of the cortical and retinal evoked potentials were significantly reduced in Parkinson's disease patients compared with the control subjects and this could not be attributed to any particular feature of the disease or its treatment. There was a significant relationship between the VEP P100 latency and the PERG amplitude. Moreover for those subjects in whom there was an interocular difference in both cortical and retinal evoked potentials, the abnormality was more commonly found in the potentials from the same eye. These findings suggest that the abnormality of the VEP in Parkinson's disease patients is, at least in part, secondary to an abnormality of the retina itself.

Nightingale, S; Mitchell, K W; Howe, J W

1986-01-01

408

Effects of distraction on pain-related somatosensory evoked magnetic fields and potentials following painful electrical stimulation  

Microsoft Academic Search

We aimed to compare the effects of distraction on pain-related somatosensory evoked magnetic fields (pain SEF) following painful electrical stimulation with simultaneous recordings of evoked potentials (pain SEP). Painful electrical stimuli were applied to the right index finger of eleven healthy subjects. A table with 25 random two-digit numbers was shown to the subjects, who were asked to add 5

Hiroshi Yamasaki; Ryusuke Kakigi; Shoko Watanabe; Minoru Hoshiyama

2000-01-01

409

Conditioning effects of sural nerve stimulation on short and long latency motor evoked potentials in lower limb muscles  

Microsoft Academic Search

The effects of conditioning sural nerve stimulation on motor evoked potentials (MEPs) in relaxed muscles of the lower limb were examined in 11 healthy adults. The study tested the hypothesis that cutaneous afferent stimulation, in the absence of muscle afferent input, facilitates the short latency MEPs evoked in lower limb muscles following transcranial magnetic stimulation of motor cortex. Non-painful (3.6

D. L. Wolfe; K. C. Hayes

1995-01-01

410

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

PubMed

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. PMID:22801526

Richardson, Andrew G; Fetz, Eberhard E

2012-07-11

411

Visual evoked potentials in early diagnosis of demyelinating diseases - a case report of Devic's disease  

PubMed Central

Summary Background Devic’s disease, also known as neuromyelinitis optica (NMO), is a severe, rare demyelinating disorder, previously considered to be a form of multiple sclerosis (MS). The aim of this study was to present the case report of 21-year-old woman with a very early diagnosis of Devic’s disease, established following electrophysiological testing. Case Report A 21-year-old woman was referred to Warsaw Medical University, Department of Ophthalmology, with subjective visual impairment. The patient underwent a full clinical examination, colour vision and Goldmann visual field testing, fluorescein angiography, OCT, multifocal ERG, and visual evoked potentials (VEPs). Conclusions Visual evoked potentials are a very useful diagnostic tool in optic nerve neuropathies. In our patient, the electrophysiological testing allowed us to establish a proper diagnosis very early, before typical clinical signs of Devic’s disease.

Langwinska-Wosko, Ewa; Szulborski, Kamil; Broniek-Kowalik, Karina

2012-01-01

412

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

PubMed

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. PMID:17123858

Zhang, Jian-Hua; Böhme, Johann F

2006-11-22

413

Total i.v. anaesthesia for transcranial magnetic evoked potential spinal cord monitoring.  

PubMed

Continuous intraoperative monitoring of transcranial magnetic motor evoked potentials (TcMMEP) can warn the surgeon of motor tract damage more effectively than somatosensory evoked potentials. As a non-invasive technique it is especially useful during post-traumatic internal fixation and is applicable whatever the level of the spinal cord at risk. Inhalation and many i.v. anaesthetics block the single pulse TcMMEP but a total i.v. anaesthetic regimen based on methohexitone, alfentanil and ketamine was effective in seven patients undergoing post-traumatic internal fixation. Consistent TcMMEP of 100-1000 mcV were obtained in all patients, with a latency change of only 2 ms above preoperative values. Good cardiovascular stability was maintained during operation. PMID:8679365

Watt, J W; Fraser, M H; Soni, B M; Sett, P K; Clay, R

1996-06-01

414

Unusual postnatal development of visually evoked potentials in four brain areas of white zebra finches.  

PubMed

The central visual system of white zebra finches is physiologically different from normally coloured (wild type) birds, although the eye pigmentation and the retinofugal projection appear to be normal. Ipsilaterally evoked potentials in the white birds are enhanced in comparison to wild type birds, whereas in albino mammals the ipsilateral component of visually evoked potentials is reduced. The present study shows that the enhancement of ipsilateral responses in white zebra finches is detectable in all areas of the tectofugal pathway, and also in the visual wulst, the only station of the thalamofugal pathway examined so far in white zebra finches. In all investigated areas, the enhancement is already obvious at 20 days after hatching, the earliest age that allows reliable recordings. A deficit in inhibition of ipsilateral stimuli, probably combined with a general increase in the number of ipsilateral projections, may cause the observed enhancements of ipsilateral responses in white birds. PMID:12834909

Bredenkötter, Manfred; Bischof, Hans-Joachim

2003-07-18

415

Mechanisms of selective attention in adults and children as reflected by evoked potentials to warning stimuli  

Microsoft Academic Search

Components of evoked potentials to stimuli differing in size and warning about the necessity of subsequent recognition of\\u000a an image at the global or local level were analyzed to identify the specific features of selective attention in adults and\\u000a seven-year-old children. In both age groups, components were found that were related to selective attention aimed at processing\\u000a a warning stimulus

T. G. Beteleva; N. E. Petrenko

2006-01-01

416

Variability of motor potentials evoked by transcranial magnetic stimulation depends on muscle activation  

Microsoft Academic Search

The purpose of this research was to determine whether motor cortex excitability assessed using transcranial magnetic stimulation (TMS) is less variable when subjects maintain a visually controlled low-level contraction of the muscle of interest. We also examined the dependence of single motor evoked potential (MEP) amplitude on stimulation intensity and pre-stimulus muscle activation level using linear and non-linear multiple regression

Warren G. Darling; Steven L. Wolf; Andrew J. Butler

2006-01-01

417

Endogenous and exogenous modulators of potentials evoked by a painful cutaneous laser (LEPs)  

Microsoft Academic Search

Little is known about the specific functions of the human cortical structures receiving nociceptive input, their relationship\\u000a to various dimensions of pain, and the modulation of these inputs by attention. We now review studies demonstrating the subdural\\u000a potentials evoked by a cutaneous laser stimulus which produces a pure pain sensation by selective activation of cutaneous\\u000a nociceptors (LEPs). These LEPs were

S. Ohara; W. S. Anderson; H. C. Lawson; H. T. Lee; F. A. Lenz

418

Comparison of electroreceptor, mechanoreceptor and optic evoked potentials in the brain of some rays and sharks  

Microsoft Academic Search

1.Central processing of electroreceptor, mechanoreceptor, and optic input in rays (primarilyTorpedo) and sharks (primarilyScyliorhinus) was studied by recording evoked potentials to both direct nerve shock and natural physiological stimulation. We found that electrosensory input has a widespread, complex central representation; convergence of different modalities occurs in the midbrain, and rays show some consistent differences from sharks in response dynamics.2.Each modality

C. J. Platt; T. H. Bullock; G. Czéh; N. Kova?evi?; Dj. Konjevi?; M. Gojkovi?

1974-01-01

419

The Use of Telemetry-Evoked Compound Action Potentials (TECAP) in Cochlear Implantation  

Microsoft Academic Search

For about 20 years, Cochlear Implants have successfully restored hearing in postlingual deaf or helped to acquire auditory\\u000a communication in prelingual deaf patients. However, only in recent years Cochlear Implant manufacturers have implemented stimulating\\u000a and recording protocols for evoked compound action potentials in order to assess auditory nerve function in relation to the\\u000a implanted device. Along with the principles of

Justus Ilgner; W. Döring; M. Westhofen

420

Assessment of sensory function in neonatal sheep with somatosensory evoked potentials: methodology and normative data  

Microsoft Academic Search

Fetal sheep are increasingly used as animal models for fetal surgical interventions such as repair of myelomeningocele. Since\\u000a behavioral observations cannot provide objective information about preservation of sensory function, we have developed a technique\\u000a for reliably recording somatosensory evoked potentials in neonatal sheep. We determined anatomic criteria for placement of\\u000a recording electrodes over the somatosensory cortex using external landmarks, and

Charles D. Yingling; Claudia Meuli-Simmen; Martin Meuli; Gregory B. Timmel; N. Scott Adzick; Michael Harrison

1999-01-01

421

Motor evoked potentials in multiple sclerosis patients without walking limitation: amplitude vs. conduction time abnormalities  

Microsoft Academic Search

We used Motor Evoked Potentials (MEPs), elicited by transcranial magnetic stimulation, for assessing a motor pathways dysfunction\\u000a in a selected group of Multiple Sclerosis (MS) patients, without limitation in walking. We selected 32 Relapsing Remitting\\u000a MS patients, in remission phase, with EDSS ? 3.5 and 20 healthy individuals with similar height and age distribution. We measured\\u000a the following MEP parameters: motor thresholds;

Andrea Gagliardo; Francesca Galli; Antonello Grippo; Aldo Amantini; Cristiana Martinelli; Maria Pia Amato; Walter Borsini

2007-01-01

422

Dipolar modelling of the scalp evoked potentials to painful contact heat stimulation of the human skin  

Microsoft Academic Search

Contact heat evoked potentials (CHEPs) were collected in 12 healthy subjects by stimulating the forearm skin with a couple of thermodes at a painful intensity. The stimulated area was 628 mm2 and the repetition rate was 0.1 Hz. The electroencephalogram was recorded by 31 electrodes placed on the scalp according to an extended 10–20 System. A dipolar model explaining the

Massimiliano Valeriani; Domenica Le Pera; David Niddam; Andrew C. N Chen; Lars Arendt-Nielsen

2002-01-01

423

Contact heat evoked potentials as a valid means to study nociceptive pathways in human subjects  

Microsoft Academic Search

Contact heat evoked potentials (CHEPs) have been difficult to elicit due to slow temperature rise times. A recently developed heat-foil technology was used to elicit pain and CHEPs. Two groups of subjects were separately stimulated at the left arm with contact heat via one fast-acting (70°C\\/s) heat-foil thermode. A set of CHEPs was recorded, each at three subjective intensities: warm;

Andrew C. N Chen; David M Niddam; Lars Arendt-Nielsen

2001-01-01

424

Future ambulation prognosis as predicted by somatosensory evoked potentials in motor complete and incomplete quadriplegia  

Microsoft Academic Search

Objective: The purpose of this prospective study was to determine the efficacy of tibial somatosensory evoked potentials (SEPs) in predicting ambulation in tetraplegic individuals. Design: This was a prospective study of a cohort of cervical spinal cord—injured patients who had SEPs recorded within 72 hours to 2 weeks post-SCI and whose ambulation outcome was followed up to 2 years post-SCI.

Stanley R. Jacobs; Natalie K. Yeaney; Gerald J. Herbison; John F. Ditunno

1995-01-01

425

Vestibular evoked myogenic potentials in patients with contralateral delayed endolymphatic hydrops  

Microsoft Academic Search

We studied vestibular evoked myogenic potentials (VEMPs) in nine patients with unilateral profound hearing loss followed\\u000a by contralateral delayed hearing fluctuation and episodic vertigo. This condition has been called contralateral delayed endolymphatic\\u000a hydrops. Five of nine ears with profound hearing loss (56%) showed an absence of VEMPs. One ear (11%) showed decreased responses,\\u000a and three ears (33%) had normal responses.

Masafumi Ohki; Masaki Matsuzaki; Keiko Sugasawa; Toshihisa Murofushi

2002-01-01

426

Tuning Characteristics of Ocular and Cervical Vestibular Evoked Myogenic Potentials in Intact and Dehiscent Ears  

Microsoft Academic Search

Cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs) to air-conducted tone bursts (250–2000 Hz) were recorded in 14 patients with superior canal dehiscence (SCD) and 32 healthy controls. For cVEMPs, the most common ‘optimal frequency’ in control ears (48.2%) was 500 Hz; for oVEMPs, it was 1000 Hz (51.8%). We found a significant interaction between age and frequency,

R. L. Taylor; A. P. Bradshaw; G. M. Halmagyi; M. S. Welgampola

2012-01-01

427

Evoked potential indices of selective hemispheric engagement in affective and phonetic tasks.  

PubMed

Evoked potentials (EPs) to a probe click stimulus were recorded from left and right temporal areas of dextral adults engaged in phonetic and prosodic processing of an emotionally charged tape recorded conversation. Attenuation of the probe EP amplitudes was significantly greater in the left and right hemispheres during the phonetic and prosodic tasks, respectively, indicating lateral dominance shifts depending on selective processing of linguistic vs affective cues conveyed by the same speech signals. PMID:6621869

Papanicolaou, A C; Levin, H S; Eisenberg, H M; Moore, B D

1983-01-01

428

Effects of octreotide on esophageal visceral perception and cerebral evoked potentials induced by balloon distension  

Microsoft Academic Search

Objective: Octreotide, a somatostatin analog, is antinociceptive and increases perception threshold in the rectum. The aim of this study was to determine whether octreotide alters esophageal sensory thresholds and cortical evoked potentials (CEPs) resulting from intraesophageal balloon distension. Methods: Twelve healthy volunteers (six men and six women, median age 25 yr, range 21–60 yr) underwent a randomized, double-blind, placebo-controlled trial

Brian T Johnston; Jay Shils; Louis P Leite; Donald O Castell

1999-01-01

429

Motor versus somatosensory evoked potential changes after acute experimental spinal cord injury in rats  

Microsoft Academic Search

Summary In this study, averaged cortical somatosensory evoked potentials (SEP) after sciatic nerve stimulation, and lower extremity muscle responses after motor cortex stimulation (MEP) were compared in rats. 10 animals served as light (25g-cm) and 10 animals as severe (80g-cm) acute spinal cord injury group after weight dropping trauma. After the initial loss of components, both SEP and MEP recovered

M. Zileli; J. Schramm

1991-01-01

430

Cortical evoked potentials as indicators of auditory-visual cross-modal association in young adults  

Microsoft Academic Search

Auditory evoked potentials (AEPs) were studied from scalp locations Cz and Oz on 37 adults aged 20–22 years during sensori-sensorial\\u000a association of a weak sound (S) and a strong flash of light (L). After sound alone repetition (habituation), S-L association\\u000a modified AEP: first, it caused a generalized orienting response expressed as increasing of Cz and Oz amplitude AEPs. Then,\\u000a this

N. Bruneau; S. Roux; B. Garreau; J. Martineau; G. Lelord

1990-01-01

431

Behavioral and auditory evoked potential audiograms of a false killer whale (Pseudorca crassidens)  

Microsoft Academic Search

Behavioral and auditory evoked potential (AEP) audiograms of a false killer whale were measured using the same subject and experimental conditions. The objective was to compare and assess the correspondence of auditory thresholds collected by behavioral and electrophysiological techniques. Behavioral audiograms used 3-s pure-tone stimuli from 4 to 45 kHz, and were conducted with a go\\/no-go modified staircase procedure. AEP

Michelle M. L. Yuen; Paul E. Nachtigall; Marlee Breese; Alexander Ya. Supin

2005-01-01

432

Middle and long latency somatosensory evoked potentials after painful laser stimulation in patients with fibromyalgia syndrome  

Microsoft Academic Search

Ten femalespatients with fibromyalgia syndrome (FS) were investigated with laser evoked potentials (LEPs) after hand stimulations and compared with 10 female pain-free and age-matched control patients. FS patients exhibited significantly lower heat pain thresholds than controls (P < 0.05) and had higher amplitudes of LEP components N170 (P < 0.01) and P390 (P < 0.05) in response to intensities of

J. Lorenz; K. Grasedyck; B. Bromm

1996-01-01

433

The color-vision approach to emotional space: Cortical evoked potential data  

Microsoft Academic Search

A framework for accounting for emotional phenomena proposed by Sokolov and Boucsein (2000) employs conceptual dimensions that\\u000a parallel those of hue, brightness, and saturation in color vision. The approach that employs the concepts of emotional quality,\\u000a intensity, and saturation has been supported by psychophysical emotional scaling data gathered from a few trained observers.\\u000a We report cortical evoked potential data obtained

Wolfram Boucsein; Florian Schaefer; Evgeni N. Sokolov; Christina Schröder; John J. Furedy

2001-01-01

434

Reflection of the Emotional Significance of Visual Stimuli in the Characteristics of Evoked EEG Potentials  

Microsoft Academic Search

Healthy subjects (n = 88) were asked to passively visualize positive and passive emotiogenic visual stimuli and also stimuli with a neutral emotional\\u000a content. Images of the International Affective Picture System (IAPS) were used. Amplitude\\/time characteristics of the components\\u000a of evoked EEG potentials (EPs), P1, N1, P2, N2, and P3 and topographic distribution of the latter components were analyzed.\\u000a The

A. A. Kovalenko; V. B. Pavlenko; S. V. Chernyi

2010-01-01

435

Visual evoked potentials to flash and pattern reversal stimulation after administration of systemic or topical scopolamine  

Microsoft Academic Search

It has previously been shown that 0.6 mg of scopolamine produces a delay in the flash visual evoked potential of young normal volunteers, while the pattern-reversal response does not change in latency. Recent work has shown that this drug differentially affects parvocellular and magnocellular systems. To investigate this effect, two studies were performed. In the first study, 0.4 mg of

Graham F. A. Harding; Rebecca Daniels; Sanjita Panchal; Neville Drasdo; Stephen J. Anderson

1994-01-01

436

Experimental fetal neurosurgery: effects of in-utero manipulations on somatosensory evoked potentials  

Microsoft Academic Search

Somatosensory evoked potentials (SEP) were used to objectively evaluate sensory function in neonatal sheep after experimental\\u000a fetal surgery. Posterior tibial (PTN) and ulnar (UN) nerves were stimulated electrically and averaged SEP were recorded from\\u000a scalp electrodes placed over the somatosensory cortex. Animals with experimentally-created myelomeningocele (MMC) showed no\\u000a SEP to PTN stimulation, but normal SEP to UN stimulation. In-utero repair

Charles D. Yingling; Claudia Meuli-Simmen; Martin Meuli; Gregory B. Timmel; Michael Harrison; N. Scott Adzick

1999-01-01

437

Auditory evoked potentials in schizophrenic patients before and during neuroleptic treatment  

Microsoft Academic Search

Summary The auditory evoked potential (AEP) components N1 and P2 were investigated under a no-task condition in a group of 14 acutely ill unmedicated schizophrenic patients and compared with the findings in an age- and sex-matched control group. In the patients, N1 latency was significantly increased, P2 latency and N1-P2 interpeak latency were reduced. There were significant relationships between AEP

Georg Adler; Wagner F. Gattaz

1993-01-01

438

A neurophysiologically-based mathematical model of flash visual evoked potentials  

Microsoft Academic Search

Evidence is presented that a neurophysiologically-inspired mathematical model, originally developed for the generation of spontaneous EEG (electroencephalogram) activity, can produce VEP (visual evoked potential)-like waveforms when pulse-like signals serve as input. It was found that the simulated VEP activity was mainly due to intracortical excitatory connections rather than direct thalamic input. Also, the model-generated VEPs exhibited similar relationships between prestimulus

Ben H. Jansen; George Zouridakis; Michael E. Brandt

1993-01-01

439

Development of the Temporal Properties of Visual Evoked Potentials to Luminance and Colour Contrast in Infants  

Microsoft Academic Search

We have studied the development of the temporal characteristics of the pattern visual evoked potentials (P-VEPs) in response to contrast reversal of patterns of low spatial frequency (0.1 c\\/deg) of either pure luminance contrast (yellow-black plaid patterns) or pure colour contrast (equiluminant red-green plaid patterns) in 15 infants between 6 and 30 weeks of age. High contrast patterns were modulated

M. CONCETTA MORRONE; ADRIANA FIORENTINI; DAVID C. BURR

1996-01-01

440

Application of rapid random stimulation (RRS) to visual evoked potentials in children  

Microsoft Academic Search

The present study was performed to examine the effects of regular (1Hz) and modified rapid random stimulation (RRS) (6 and 12Hz) on visual evoked potentials (VEPs), by simultaneously recording negative waves around 100ms, wave IV-latency, positive waves around 60ms, wave III-latency, and amplitudes calculated from peak to peak, without causing impairment of visual acuity, in 44 patients aged 5–17 years.

Maiko Fujikawa; Masaharu Ohfu; Sadatoshi Fujikawa; Tsau-Tsen Chen; Akihisa Mitsudome

1999-01-01

441

A Real-Time Brain-Computer Interface Based on Steady-State Visual Evoked Potentials  

Microsoft Academic Search

Steady-state visual evoked potential (SSVEP)-based BCIs take advantage of the stereotypical response to flicker in the visual cortex. They oer the possibility of high performance non-invasively and with minimal training time. A real-time SSVEP BCI system was de- veloped and tested on 14 control subjects. While inter- subject variability existed, the results were promising, proving that the stimulation frequency of

Remy Wahnoun; Rajiv Saigal; Ying Gu; Nicolas Paquet; Sofie DePauw

442

Temporal Aspects of Contrast Visual Evoked Potentials in the Pigmented Rat: Effect of Dark Rearing  

Microsoft Academic Search

Cortical visual evoked potentials (VEPs) in response to gratings temporally modulated in counterphase were recorded in normal and dark-reared pigmented rats. Temporal modulation was either sinusoidal (0.25–15 Hz, steady state condition) or abrupt (0.5 Hz, transient condition). In normals, the amplitude spectrum of contrast VEPs has two peaks (at about 0.5 and 4 Hz) and a high temporal frequency cut-off

TOMMASO PIZZORUSSO; MICHELA FAGIOLINI; VITTORIO PORCIATTI; LAMBERTO MAFFEI

1997-01-01

443

Analysis of pattern reversal visual evoked potentials (PRVEPs) by spline wavelets  

Microsoft Academic Search

The pattern-reversal visual evoked potentials (PRVEPs) collected from normal and demented subjects are investigated by applying the quadratic spline wavelet analysis. The data are decomposed into six octave frequency bands. For quantitative purposes, the wavelet coefficients in the residual waveform representing the delta-theta band activity (0-8 Hz) are explored to characterize the (N70-P100-N130) complex. Specifically, the coefficients corresponding to the

A. Ademoglu; E. Micheli-Tzanakou; Y. Istefanopoulos

1997-01-01

444

A periodogram-based method for the detection of steady-state visually evoked potentials  

Microsoft Academic Search

The task of objective perimetry is to scan the visual field and find an answer about the function of the visual system. Flicker-burst stimulation-a physiological sensible combination of transient and steady-state stimulation-is used to generate deterministic sinusoidal responses or visually evoked potentials (VEPs) at the visual cortex, which are derived from the electroencephalogram by a suitable electrode array. Here, the

Athanasios P. Liavas; George V. Moustakides; Gunter Henning; Emmanuil Z. Psarakis; Peter Husar

1998-01-01

445

Steady-state visually evoked potentials: Focus on essential paradigms and future perspectives  

Microsoft Academic Search

After 40 years of investigation, steady-state visually evoked potentials (SSVEPs) have been shown to be useful for many paradigms in cognitive (visual attention, binocular rivalry, working memory, and brain rhythms) and clinical neuroscience (aging, neurodegenerative disorders, schizophrenia, ophthalmic pathologies, migraine, autism, depression, anxiety, stress, and epilepsy). Recently, in engineering, SSVEPs found a novel application for SSVEP-driven brain–computer interface (BCI) systems.

François-Benoît Vialatte; Monique Maurice; Justin Dauwels; Andrzej Cichocki

2010-01-01

446

Flash visual evoked potentials at 2-year-old infants with different birth weights  

Microsoft Academic Search

Background  Increased prevalence of visual impairments has been reported in preterm populations. However, it remains unclear about the\\u000a long-term visual electrophysiological outcomes and their association with visual cognitive functions in premature infants.\\u000a We investigated visual electrophysiological outcome of 2-year-old infants of different birth weights by flash visual evoked\\u000a potentials (FVEPs) in order to explore the correlation between visual cognitive functions and

Jing-Jing Feng; Ting-Xue Wang; Chen-Hao Yang; Wei-Ping Wang; Xiu Xu

2010-01-01

447

Giant visually-evoked potentials without myoclonus in the Heidenhain type of Creutzfeld–Jakob disease  

Microsoft Academic Search

In a 64-year old woman with progressive visual impairment for 4 weeks, probable Creutzfeld–Jakob disease without myoclonus was diagnosed after rapidly progressive mental deterioration had also developed, and CSF and EEG showed characteristic findings. Pattern-reversal and flash visually-evoked potentials, recorded 5, 6, 7 and 8 weeks after onset, showed a maximum P100 latency of 210 ms, 8 weeks after onset,

J Finsterer; C Bancher; B Mamoli

1999-01-01

448

Enabling Fast Brain-Computer Interaction by Single-Trial Extraction of Visual Evoked Potentials  

Microsoft Academic Search

This paper investigates the challenging issue of enabling fast brain-computer interaction to construct a mental speller. Exploiting visual evoked potentials as communication carriers, an online paradigm called “imitating-human-natural-reading” is realized. In this online paradigm, single-trial estimation with the intrinsically real-time feature should be used instead of grand average that is traditionally used in the cognitive or clinical experiments. By the

Min Chen; Jinan Guan; Haihua Liu

2011-01-01

449

Sweep Pattern Visual Evoked Potential Acuity in Children during Their Periods of Visual Development  

Microsoft Academic Search

Purpose: To study the clinical usage of sweep pattern visual evoked potential (SPVEP) acuity in children’s visual development periods and compare the amplitude-spatial frequency (A-SP) function regression method with the amplitude-logarithm of the visual angle (A-logVA) function regression method in evaluating the SPVEP acuity of children, especially those who have poor visual acuities. Methods: Twenty-six eyes of 26 amblyopic children

Lu Li; Yu Su; Chang-zheng Chen; Chao Feng; Hong-mei Zheng; Yi-qiao Xing

2011-01-01

450

Central pontine myelinolysis: diagnosis by computed tomography, magnetic resonance and evoked potentials.  

PubMed

The intravital diagnosis of central pontine myelinolysis has become possible with the introduction of computed tomography and magnetic resonance into neurological diagnostics. These tools are of special value when neurological signs of a ventral pontine lesion are lacking, as in the case we describe. Auditory evoked potentials likewise confirm their diagnostic value with regard both to the site of the lesion and to its dorsal extent toward the pontine tegmentum. PMID:3804711

Mossuto, L; Fattapposta, F; Rossi, F

1986-12-01

451

Electroencephalogram and visual evoked potential generation in a mathematical model of coupled cortical columns  

Microsoft Academic Search

This study deals with neurophysiologically based models simulating electrical brain activity (i.e., the electroencephalogram or EEG, and evoked potentials or EPs). A previously developed lumped-parameter model of a single cortical column was implemented using a more accurate computational procedure. Anatomically acceptable values for the various model parameters were determined, and a multi-dimensional exploration of the model parameter-space was conducted. It

Ben H. Jansen; Vincent G. Rit

1995-01-01

452

Human cerebral potentials evoked by CO 2 laser stimuli causing pain  

Microsoft Academic Search

Brief radiant heat pulses, generated by a CO2 laser, were used to activate slowly conducting afferents in the hairy skin in man. In order to isolate C-fibre responses a preferential A-fibre block was applied by pressure to the radial nerve at the wrist. Stimulus estimation and evoked cerebral potentials (EP), as well as reaction times, motor and sudomotor activity were

B. Bromm; R.-D. Treede

1987-01-01

453

The reproducibility of binocular pattern reversal visual evoked potentials: a single subject design  

Microsoft Academic Search

This study aimed to investigate the within-participant variability over time of both amplitude and peak latency measures of\\u000a pattern reversal visual evoked potentials (pVEPs). As a large number of factors are known to contribute to the variability\\u000a of the pVEPs (such as fixation instability and drowsiness), testing was conducted in controlled conditions with two co-operative\\u000a participants. PVEPs were recorded during

Tessa B. Mellow; Alki Liasis; Ruth Lyons; Dorothy A. Thompson

2011-01-01

454

Can Vestibular-Evoked Myogenic Potentials Help Differentiate M?ni?re Disease from Vestibular Migraine?  

PubMed Central

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.

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

2013-01-01

455

Influence of constraint-induced movement therapy upon evoked potentials in rats with cerebral infarction.  

PubMed

Constraint-induced movement therapy (CIMT) is an effective treatment promoting motor recovery of upper extremity function in stroke patients. The objective of the present study was to determine the effect of CIMT on the evoked potentials in rats with focal cerebral cortical ischemia induced by endothelin-1 (ET-1). Thirty rats were randomly assigned to the sham, infarct or CIMT groups. ET-1 was injected stereotaxically into the forelimb area of the cerebral cortex in the dominant hemisphere. Custom-made constraint jackets were applied to limit movement of the unaffected forelimb in the CIMT group. Motor and sensory function of the forelimb was evaluated by a pellet retrieval task and forearm asymmetry test. Electrophysiologic changes were evaluated by motor-evoked potentials (MEPs) and somatosensory-evoked potentials (SEPs). The location and extent of cerebral ischemia were confirmed and compared histologically. The CIMT group showed better recovery in the pellet retrieval task. Forelimb use was more symmetrical in the CIMT group. The waveform of the SEP was reversed and delayed in the infarct group, but it was preserved in the CIMT group with amplitude decrease only. The estimated volume of infarction was smaller in the CIMT group, although statistically not significant. The results demonstrate that CIMT can promote recovery of motor function in focal cerebral cortical infarcts, and that recovery may be related to reorganization of the cerebral neuronal network in the somatosensory pathway. PMID:23043504

Joo, Hyung W; Hyun, Jung K; Kim, Tae U; Chae, Sang H; Lee, Young I; Lee, Seong J

2012-10-08

456

Middle latency auditory evoked potentials in congenitally blind and normal sighted subjects.  

PubMed

Middle latency auditory evoked potentials were recorded in two groups of ten subjects each, viz, congenitally blind (CB) and age-matched subjects with normal vision (NV). The age range for both groups was 13 to 16 years. The CB group subjects had peripheral deficits, with absence of visual evoked responses. The peak latency of the Nb wave (the maximum negativity between 38 and 48 ms) was significantly lower in the CB group compared to NV group (p < .05, one-tailed, two factor ANOVA, Tukey test). In addition to these recordings from the vertex, recordings were also made from occipital areas, to test whether the visual cortex contributes to information processing at primary auditory cortical levels in the blind, as was reported in earlier studies on the generation of potentials during auditory selective attention. No such effect was observed. Hence, it appears that in blind subjects changes in generators of auditory middle latency evoked potentials are mainly related to latency, rather than to scalp distribution of these components. PMID:9285292

Naveen, K V; Srinivas, R S; Nirmala, K S; Nagendra, H R; Telles, S

1997-06-01

457

The contribution of remifentanil to middle latency auditory evoked potentials during induction of propofol anesthesia.  

PubMed

There is a debate regarding whether opioids, as a component of general anesthesia, are adequately reflected in the assessment of anesthesia based on derivatives of the electroencephalogram. To test the hypothesis of a possible quantitative contribution of remifentanil on middle latency auditory evoked potentials, we studied its interaction with propofol anesthesia in 45 unpremedicated male patients undergoing elective lower limb orthopedic surgery. They were allocated randomly to three groups. The first two groups received remifentanil either with a high (8 ng mL(-1)) or a low (3 ng mL(-1) target concentration using target-controlled infusion (TCI). The third group received spinal anesthesia instead of remifentanil. Anesthesia was induced by a stepwise increase in propofol concentration using TCI. The auditory evoked potential index (AEPex) and calculated propofol effect site concentrations were determined at loss of consciousness and the reaction to laryngeal mask airway insertion was noted. The propofol infusion was then converted to a closed-loop TCI using an AEPex value of 40 as the target. We found no significant contribution of remifentanil alone on the auditory evoked response, whereas increasing concentrations of remifentanil led to a significant decrease of the calculated propofol effect site concentrations (P = 0.023) necessary for unconsciousness. Prediction probability for AEPex was inversely related to the remifentanil concentration and was best for the control group, which received propofol alone. These results support previous findings of a quantitative interaction between remifentanil and propofol for loss of consciousness but question the specific contribution of remifentanil to auditory evoked potentials. PMID:17000801

Schraag, Stefan; Flaschar, Joachim; Schleyer, Manuela; Georgieff, Michael; Kenny, Gavin N C

2006-10-01

458

Ocular vestibular-evoked myogenic potentials (oVEMPs) require extraocular muscles but not facial or cochlear nerve activity  

Microsoft Academic Search

ObjectivesCervical vestibular evoked myogenic potentials (cVEMPs) have been found to be useful for clinical testing of vestibular function. Recently, investigators showed that short-latency, initially negative surface EMG potentials can be recorded around the extraocular muscles (oVEMPs) in response to air-conducted sound (ACS), bone-conducted vibration (BCV), and head taps. Although these evoked potentials, which are located around the eyes, most likely

Yasuhiro Chihara; Shinichi Iwasaki; Munetaka Ushio; Chisato Fujimoto; Akinori Kashio; Kenji Kondo; Ken Ito; Takahiro Asakage; Tatsuya Yamasoba; Kimitaka Kaga; Toshihisa Murofushi

2009-01-01

459

Visual evoked potentials for attentional gating in a brain-computer interface.  

PubMed

For synchronous brain-computer interface (BCI) paradigms tasks that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of voluntary modulation as well as evoked responses. For these paradigms, the evoked potential is often overlooked as a source of artifact. In this paper, we put forth the hypothesis that cue priming, as a mechanism for attentional gating, is predictive of motor imagery performance, and thus a viable option for self-paced (asynchronous) BCI applications. We approximate attention by the amplitude features of visually evoked potentials (VEP)s found using two methods: trial matching to an average VEP template, and component matching to a VEP template defined using independent component analysis (ICA). Templates were used to rank trials that display high vs. low levels of fixation. Our results show that subject fixation, measured by VEP response, fails as a predictor of successful motor-imagery task completion. The implications for the BCI community and the possibilities for alternative cueing methods are given in the conclusions. PMID:23366247

Geronimo, Andrew; Schiff, Steven J; Kamrunnahar, Mst

2012-01-01

460

Visual evoked potentials for attentional gating in a brain-computer interface  

PubMed Central

For synchronous brain-computer interface (BCI) paradigms tasks that utilize visual cues to direct the user, the neural signals extracted by the computer are representative of voluntary modulation as well as evoked responses. For these paradigms, the evoked potential is often overlooked as a source of artifact. In this paper, we put forth the hypothesis that cue priming, as a mechanism for attentional gating, is predictive of motor imagery performance, and thus a viable option for self-paced (asynchronous) BCI applications. We approximate attention by the amplitude features of visually evoked potentials (VEP)s found using two methods: trial matching to an average VEP template, and component matching to a VEP template defined using independent component analysis (ICA). Templates were used to rank trials that display high vs. low levels of fixation. Our results show that subject fixation, measured by VEP response, fails as a predictor of successful motor-imagery task completion. The implications for the BCI community and the possibilities for alternative cueing methods are given in the conclusions.

Geronimo, Andrew; Schiff, Steven J.; Kamrunnahar, Mst

2013-01-01

461

[Visual evoked potential abnormalities in a girl with brain stem encephalitis (Bickerstaff)].  

PubMed

A 16-month-old girl was admitted because of bilateral ophthalmoplegia, left blepharoptosis, and disturbance of consciousness. Her symptoms resolved spontaneously within a week after admission, but mild left abducens palsy remained. The cranial computed tomography showed a mild non-specific brain atrophy. The auditory brain stem response was normal. Visual evoked potentials (VEPs) to flash stimuli were repeated serially after the onset. No significative patterns of VEP were evoked during the acute stage. However, three months after the onset, an asymmetrical pattern, namely left-sided abnormalities (not-identified P 100 wave, etc.), was observed. The asymmetrical pattern of VEP diminished six months after. And a bilaterally normal VEP pattern was found twelve months after. PMID:2223189

Kataoka, K; Okuno, T; Mikawa, H

1990-09-01

462

The effect of gaze direction on the ocular vestibular evoked myogenic potential produced by air-conducted sound  

Microsoft Academic Search

ObjectiveTo assess the effects of vertical and horizontal gaze, head rotation, body position, and vision on the ocular vestibular evoked myogenic potential (OVEMP) produced by air-conducted (AC) sound.

Sendhil Govender; Sally M. Rosengren; James G. Colebatch

2009-01-01

463

Ocular vestibular-evoked myogenic potentials to bone-conducted vibration in superior vestibular neuritis show utricular function  

Microsoft Academic Search

ObjectiveTo determine whether the first negative component (n10) of the ocular vestibular-evoked myogenic potential (oVEMP) to bone-conducted vibration (BCV) is due primarily to activation of the utricular macula.

Leonardo Manzari; AnnaRita Tedesco; Ann M. Burgess; Ian S. Curthoys

2010-01-01

464

Abnormal cervical vestibular-evoked myogenic potential in anterior inferior cerebellar artery territory infarction: Frequency, pattern, and a determinant  

Microsoft Academic Search

BackgroundThere has been no systematic study that carefully investigates the characteristic features of abnormal cervical vestibular-evoked myogenic potential (cVEMP) response associated with the AICA territory infarction.

Byung-Hoon Ahn; Hyun-Ah Kim; Hyon-Ah Yi; Sun-Young Oh; Hyung Lee

2011-01-01

465

On the Visually Evoked Potentials in the Cerebral Visual, Somatosensory, Motor and Association Areas of Monkeys (Macaca Cyclopis).  

National Technical Information Service (NTIS)

Seventeen unanesthetized monkeys were immobilized and masspotentials (EEG and evoked potentials) before and during flashing light stimulation to atropinized eyes were led by grosselectrodes from the cerebral visual (occipital cortex), association (superio...

N. Ochi

1968-01-01

466

Effects of induced hyperthermia on visual evoked potentials and saccade parameters in normal subjects and multiple sclerosis patients  

Microsoft Academic Search

A convenient method for raising body temperature has been developed and used to evaluate temperature effects on visual evoked potentials and saccade reaction time and velocity in five normal subjects and five patients with multiple sclerosis.

S Bajada; F L Mastaglia; J L Black; D W Collins

1980-01-01

467

Effects of induced hyperthermia on visual evoked potentials and saccade parameters in normal subjects and multiple sclerosis patients.  

PubMed Central

A convenient method for raising body temperature has been developed and used to evaluate temperature effects on visual evoked potentials and saccade reaction time and velocity in five normal subjects and five patients with multiple sclerosis. Images

Bajada, S; Mastaglia, F L; Black, J L; Collins, D W

1980-01-01

468

Mismatch Negativity and Adaptation Measures of the Late Auditory Evoked Potential in Cochlear Implant Users  

PubMed Central

A better understanding of the neural correlates of large variability in cochlear implant (CI) patients’ speech performance may allow us to find solutions to further improve CI benefits. The present study examined the mismatch negativity (MMN) and the adaptation of the late auditory evoked potential (LAEP) in 10 CI users. The speech syllable /da/ and 1-kHz tone burst were used to examine the LAEP adaptation. The amount of LAEP adaptation was calculated according to the averaged N1-P2 amplitude for the LAEPs evoked by the last 3 stimuli and the amplitude evoked by the first stimulus. For the MMN recordings, the standard stimulus (1-kHz tone) and the deviant stimulus (2-kHz tone) were presented in an oddball condition. Additionally, the deviants alone were presented in a control condition. The MMN was derived by subtracting the response to the deviants in the control condition from the oddball condition. Results showed that good CI performers displayed a more prominent LAEP adaptation than moderate-to-poor performers. Speech performance was significantly correlated to the amount of LAEP adaptation for the 1-kHz tone bursts. Good performers displayed large MMNs and moderate-to-poor performers had small or absent MMNs. The abnormal electrophysiological findings in moderate-to-poor performers suggest that long-term deafness may cause damage not only at the auditory cortical level, but also at the cognitive level.

Zhang, Fawen; Hammer,