ORCID Profile
0000-0002-3830-7214
Current Organisations
Royal Prince Alfred Hospital
,
University of New South Wales
,
University of Newcastle Australia
,
Macquarie University
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Publications
Cervical dystonia responsive to acoustic and galvanic vestibular stimulation
Publisher: Wiley
Date: 06-06-2006
DOI: 10.1002/MDS.20982
Abstract: We examined the effects of acoustic and galvanic vestibular stimulation in a patient with cervical dystonia. Acoustic stimulation consisted of three conditions: "baseline" (no stimulation), "vestibular" (500 Hz bone-conducted tone bursts), and "control" (5,000 Hz tone bursts). Rectified electromyographic activity in the sternocleidomastoid was measured. Galvanic stimulation (1.5-2.5 mA current steps) was delivered to the mastoids, and head acceleration was measured. Vestibular acoustic stimulation reduced neck muscle activity between 16% and 44% (P < 0.001), and galvanic stimulation reduced head acceleration by 22.5% (P = 0.028). The patient reported subjective improvement in head control. Vestibular stimulation can reduce neck muscle activity in cervical dystonia and give symptomatic relief.
Safe levels of acoustic stimulation: Comment on effects of acoustic stimuli used for vestibular evoked myogenic potential studies on the cochlear function
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2014
A source analysis of short-latency vestibular evoked potentials produced by air- and bone-conducted sound
Publisher: Elsevier BV
Date: 08-2008
DOI: 10.1016/J.CLINPH.2008.03.027
Abstract: To map short-latency vestibular evoked potentials (VsEPs) using air- (AC) and bone-conducted (BC) sound and to perform source analysis to determine their origin. Ten normal volunteers, chosen to have low-normal thresholds for acoustic vestibular activation, participated. In the first part, the subjects' in idual thresholds for vestibular activation (V(T)) were established using vestibular evoked myogenic potentials (VEMPs) recorded from the sternocleidomastoid muscles. AC sound was delivered with headphones and BC sound with a commercial B71 bone vibrator. In the second part, VsEPs were recorded using Ag/AgCl scalp electrodes in a 10-20 montage supplemented by infra-ocular, mastoid and cerebellar electrodes. Stimuli were 2ms pips, consisting of a single cycle of 500 Hz, presented at +18 dB re V(T) ("vestibular" condition) and -3 dB re V(T) (control condition). Following the control stimulus, auditory mid-latency responses (MLRs) were observed. In the vestibular condition, two dominant groups of non-MLR potentials of presumed vestibular origin appeared (vestibular evoked potentials, or VsEPs), which consisted of a P10-N17 complex maximal at Pz, and an N15-P21 complex maximal at Fpz. Large potentials were also recorded from the infra-ocular electrodes at similar latencies. Source analysis indicated that the two complexes were largely accounted for by a combination of ocular vestibular evoked myogenic potentials (OVEMPs) and sub-cortical sources (possibly vestibular cerebellum), with a smaller contribution from anterior cortical and other myogenic sources. Both the N15 and P10 potentials appear to receive an ocular myogenic contribution but both appear also to receive a contribution from other central structures. The P10 and N15 complexes appear to represent the activity of otolith-dependent projections.
Evidence of a Vestibular Origin for Crossed-Sternocleidomastoid Muscle Responses to Air-Conducted Sound
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 31-10-2019
DOI: 10.1097/AUD.0000000000000813
Abstract: Small, excitatory surface potentials can sometimes be recorded from the contralateral sternocleidomastoid muscle (SCM) following monaural acoustic stimulation. Little is known about the physiological properties of these crossed reflexes. In this study, we sought the properties of crossed SCM responses and through comparison with other cochlear and vestibular myogenic potentials, their likely receptor origin. Surface potentials were recorded from the ipsilateral and contralateral SCM and postauricular (PAM) muscles of 11 healthy volunteers, 4 patients with superior canal dehiscence and 1 with profound hearing loss. Air-conducted clicks of 105 dB nHL and tone bursts (250 to 4000 Hz) of 100 dB nHL were presented monaurally through TDH 49 headphones during head elevation. Click-evoked responses were recorded under two conditions of gaze in random order: gaze straight ahead and rotated hard toward the contralateral recording electrodes. Amplitudes (corrected and uncorrected) and latencies for crossed SCM responses were compared with vestibular (ipsilateral SCM) and cochlear (PAM) responses between groups and across the different recording conditions. Surface waveforms were biphasic positive-negative for the ipsilateral SCM, and negative-positive for the contralateral SCM and PAM. There were significant differences in the litudes and latencies ( p = 0.004) for click responses of healthy controls across recording sites. PAM responses had the largest mean-corrected litudes (2.3 ± 2.8) and longest latencies (13.0 ± 1.2 msec), compared with ipsilateral (1.6 ± 0.5 12.0 ± 0.7 msec) and contralateral (0.8 ± 0.3 10.4 ± 1.0 msec) SCM responses. Uncorrected litudes and muscle activation for PAM increased by 104.4% and 46.8% with lateral gaze respectively, whereas SCM responses were not significantly affected. Click responses of patients with superior canal dehiscence followed a similar latency, litude, and gaze modulation trend as controls. SCM responses were preserved in the patient with profound hearing loss, yet all PAM were absent. There were significant differences in the frequency tuning of the three reflexes ( p 0.001). Tuning curves of healthy controls were flat for PAM and down sloping for ipsilateral and contralateral SCM responses. For superior canal dehiscence, they were rising for PAM and slightly down sloping for SCM responses. Properties of crossed SCM responses were similar, though not identical, to those of ipsilateral SCM responses and are likely to be predominantly vestibular in origin. They are unlikely to represent volume conduction from the PAM as they were unaffected by lateral gaze, were shorter in latency, and had different tuning properties. The influence of crossed vestibulo-collic pathways should be considered when interpreting cervical vestibular-evoked myogenic potentials recorded under conditions of binaural stimulation.
A short latency vestibular evoked potential (VsEP) produced by bone-conducted acoustic stimulation
Publisher: Acoustical Society of America (ASA)
Date: 12-2003
DOI: 10.1121/1.1628249
Abstract: In this paper data are presented from an experiment which provides evidence for the existence of a short latency, acoustically evoked potential of probable vestibular origin. The experiment was conducted in two phases using bone-conducted acoustic stimulation. In the first phase subjects were stimulated with 6-ms, 500-Hz tone bursts in order to obtain the threshold VT for vestibular evoked myogenic potentials (VEMP). It was confirmed that the difference between bone-conducted auditory and acoustic vestibular thresholds was slightly over 30 dB. The estimated threshold was then used as a reference value in the second part of the experiment to stimulate subjects over a range of intensities from −6 to +18 dB (re:VT). Averaged EEG recordings were made with eight Ag/AgCl electrodes placed on the scalp at Fpz, F3, F4, F7, F8, Cz, T3, and T4 according to the 10–20 system. Below VT auditory midlatency responses (MLRs) were observed. Above VT two additional potentials appeared: a positivity at about 10 ms (P10) which was maximal at Cz, and a negativity at about 15 ms (N15) which was maximal at Fpz. Extrapolation of the growth functions for the P10 and N15 indicated a threshold close to VT, consistent with a vestibular origin of these potentials. Given the low threshold of vestibular acoustic sensitivity it is possible that this mode may make a contribution to the detection of and affective responses to loud low frequency sounds. The evoked potentials may also have application as a noninvasive and nontraumatic test of vestibular projections to the cortex.
Vestibular hypersensitivity to sound in superior canal dehiscence: Large evoked responses in the legs produce little postural sway
Publisher: Elsevier BV
Date: 07-2008
DOI: 10.1016/J.CLINPH.2008.03.021
Abstract: Patients with superior canal dehiscence (SCD) typically have enhanced sound-evoked vestibular reflexes, such as vestibulo-collic and vestibulo-ocular reflexes. We wished to investigate whether sound-evoked lower limb EMG responses and postural sway are also enhanced in this condition. Eight patients with CT confirmed SCD (11 affected ears) and 8 age-matched normal controls participated. Three sound-evoked responses were measured vestibulo-collic reflexes (i.e. vestibular-evoked myogenic potentials, VEMPs), lower limb vestibulo-spinal reflexes and body sway (centre of pressure in mm). Sound stimuli were 500 Hz air-conducted tone bursts of varying lengths (VEMPs: 2 ms vestibulo-spinal: 20 ms sway: 1s and 200 ms) set at fixed levels above each subject's VEMP threshold. SCD patients had very large VEMP and vestibulo-spinal responses following high intensity stimulation, but at the matched intensity of 15 dB above threshold litudes were similar in both SCD patients and controls. The litude of both responses increased linearly with increasing stimulus intensity in both groups. Large ( approximately 20mm), stereotyped sway responses were present in only one (atypical) patient with high intensity stimulation. Small ( approximately 2mm) sway responses were present in the remaining patients, and began immediately following the vestibulo-spinal responses. Despite the presence of large vestibular reflexes, there is usually very little body sway in response to loud sounds in SCD patients. Large short-latency vestibulo-spinal reflexes in SCD do not necessarily evoke large sway responses.
Vestibular activation by bone conducted sound
Publisher: BMJ
Date: 06-2003
Abstract: To examine the properties and potential clinical uses of myogenic potentials to bone conducted sound. Myogenic potentials were recorded from normal volunteers, using bone conducted tone bursts of 7 ms duration and 250-2000 Hz frequencies delivered over the mastoid processes by a B 71 clinical bone vibrator. Biphasic positive-negative (p1n1) responses were recorded from both sternocleidomastoid (SCM) muscles using averaged unrectified EMG. The best location for stimulus delivery, optimum stimulus frequency, stimulus thresholds, and the effect of aging on evoked response litudes and thresholds were systematically examined. Subjects with specific lesions were studied. Vestibular evoked myogenic potentials (VEMP) to air conducted 0.1 ms clicks, 7 ms/250-2000 Hz tones, and forehead taps were measured for comparison. Bone conducted sound evoked short latency p1n1 responses in both SCM muscles. Ipsilateral responses occurred earlier and were usually larger. Mean (SD) p1 and n1 latencies were 13.6 (1.8) and 22.3 (1.2) ms ipsilaterally and 14.9 (2.1) and 23.7 (2.7) ms contralaterally. Stimuli of 250 Hz delivered over the mastoid process, posterosuperior to the external acoustic meatus, yielded the largest litude responses. Like VEMP in response to air conducted clicks and tones, p1n1 responses were absent ipsilaterally in subjects with selective vestibular neurectomy and preserved in those with severe sensorineural hearing loss. However, p1n1 responses were preserved in conductive hearing loss, whereas VEMP to air conducted sound were abolished or attenuated. Bone conducted response thresholds were 97.5 (3.9) dB SPL/30.5 dB HL, significantly lower than thresholds to air conducted clicks (131.7 (4.9) dB SPL/86.7 dB HL) and tones (114.0 (5.3) dB SPL/106 dB HL). Bone conducted sound evokes p1n1 responses (bone conducted VEMP) which are a useful measure of vestibular function, especially in the presence of conductive hearing loss. For a given perceptual intensity, bone conducted sound activates the vestibular apparatus more effectively than air conducted sound.
Single trial detection of human vestibular evoked myogenic potentials is determined by signal-to-noise ratio
Publisher: American Physiological Society
Date: 07-2010
DOI: 10.1152/JAPPLPHYSIOL.01139.2009
Abstract: Vestibular reflexes in humans can be assessed by means of acoustically evoked responses of myogenic origin. For the vestibular-collic pathway this is termed the vestibular evoked myogenic potential (or VEMP) and for the vestibular-ocular pathway the ocular VEMP (or OVEMP). Usually VEMPs require an averaging process to obtain a clear response against the background myogenic activity, but depending on the combination of target reflex and stimulus mode, in some cases clear responses can be observed in single trials without averaging. We aimed to test whether this difference in detectability was simply related to signal-to-noise ratio (SNR), or a manifestation of some other difference in the reflex pathways. In four healthy subjects we recorded VEMPs and OVEMPs in response to 2-ms, 500-Hz sound pips and 10-ms, 100-Hz transmastoid vibrations at four intensity levels, and also determined thresholds. A plot of probability of detection P vs. SNR for all subjects and conditions fell onto a single sigmoid curve. When fitted by a logistic function after linearization a regression yielded an R 2 of 0.89 ( n = 64, p 0.001), with parameter estimates of μ = 2.9 and σ = 2.0. Three patients with superior canal dehiscence, characterized by significantly lowered thresholds for sound-activated responses, exhibited a similar detection curve. We conclude that single trial detection of evoked myogenic potentials is a property mainly determined by SNR. Thus vestibular reflexes, differing in both their response magnitude and in their levels of myogenic activity by more than an order of magnitude, can be described by a single relationship when their magnitude is expressed relative to background activity, demonstrating the fundamental importance of the SNR.
Maternal separation in early life impairs tumor immunity in adulthood in the F344 rat
Publisher: Informa UK Limited
Date: 27-03-2011
Ocular and cervical vestibular evoked myogenic potentials produced by air- and bone-conducted stimuli: Comparative properties and effects of age
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.CLINPH.2011.04.001
Abstract: To compare litudes, latencies, symmetry and the effects of age for both ocular and cervical vestibular evoked myogenic potentials (oVEMPs and cVEMPs) produced by different types of air- (AC) and bone-conducted (BC) stimuli. Sixty-one normal subjects aged 18-80 years participated. Both reflexes were recorded in response to AC clicks, AC and BC 500 Hz tone bursts, forehead taps and lateral mastoid accelerations. AC tone bursts, clicks and BC tone bursts evoked oVEMPs in 81%, 59% and 65% of ears, respectively. The AC stimuli had higher thresholds for oVEMPs than for cVEMPs and all three stimuli produced higher asymmetry for the oVEMP than for the cVEMP. Forehead taps and lateral pulses evoked oVEMPs in 96% and 92% of cases. AC click- and BC tone burst-evoked oVEMPs showed a significant decline with age. AC stimulation and BC tone bursts delivered to the mastoid are less effective in evoking oVEMPs than in evoking cVEMPs, have high degrees of asymmetry in normals and appear to decline with age. Forehead taps and lateral accelerations produce more symmetrical effects and showed no significant decline with age. Stimulus properties need to be considered when deciding the most appropriate way to investigate vestibular function using oVEMPs.
Vestibular-evoked myogenic potentials (VEMPs)
Publisher: Elsevier
Date: 2010
Safe levels of acoustic stimulation for vemps: Comment on sudden bilateral hearing loss after cervical and ocular vestibular evoked myogenic potentials
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2016
Vestibular evoked potentials (VsEPs) in patients with severe to profound bilateral hearing loss
Publisher: Elsevier BV
Date: 05-2006
DOI: 10.1016/J.CLINPH.2005.12.026
Abstract: To confirm the exclusive vestibular dependence of the evoked potentials (P10 and N15) recorded in normal subjects, by recording the potentials evoked in response to bone-conducted sound stimulation in patients with bilateral hearing loss. Fourteen patients with severe to profound bilateral hearing loss were stimulated via a B71 bone-vibrator above the mastoid with bone-conducted tone bursts (500 Hz, 6 ms) at fixed levels above their in idual vestibular evoked myogenic potential (VEMP) thresholds. Surface potentials were recorded from scalp electrodes at F7, F3, Fpz, F4, F8, T3, Cz, and T4 and referred to linked earlobes. Seven of 14 patients had suitable VEMPs to the maximal stimulus. P10 and N15 potentials were present in each of these 7 patients, but were absent in patients with absent VEMP responses. The potentials were only detected above VEMP threshold, and were similar in size, shape and latency to those recorded in normal controls at a matched intensity above VEMP threshold. Normal P10 and N15 potentials can be recorded from patients with profound bilateral hearing loss using bone-conducted acoustic stimulation of the vestibular apparatus. The P10 and N15 appear to be dependent purely upon vestibular activation.
Vestibular neuritis has selective effects on air- and bone-conducted cervical and ocular vestibular evoked myogenic potentials
Publisher: Elsevier BV
Date: 06-2011
DOI: 10.1016/J.CLINPH.2010.12.040
Abstract: To characterise the changes in cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials to different stimuli in patients with vestibular neuritis (VN). cVEMPs and oVEMPs were recorded using air-conducted (AC clicks and short tone bursts) and bone-conducted (BC lateral impulses and taps) stimuli in VN patients (n=23) and normals (n=40). AC evoked cVEMPs revealed few abnormalities, significantly less than for AC evoked oVEMPs (cVEMP: 22% vs oVEMP: 68%, P 0.05) for both reflexes. Although forehead taps produced low rates of abnormalities for both reflexes (33% vs 13%, P>0.05), response litudes were smaller from the affected ear (P<0.05). AC stimuli were associated with low abnormality rates of cVEMPs, consistent with sparing of inferior nerve function in VN, but frequent abnormalities of oVEMPs. The high rates of abnormalities shown for lateral impulses suggest a dependence on superior nerve (i.e. utricular) afferents for both oVEMPs and cVEMPs. Lateral impulses behave as expected for utricular function and AC cVEMPs for saccular function. The AC evoked oVEMP seems to depend on the integrity of the superior vestibular nerve, possibly due to saccular afferents travelling in it.
Vestibular evoked myogenic potentials: Past, present and future
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.CLINPH.2009.10.016
Abstract: 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 conventional method for recording the VEMP involves measuring electromyographic (EMG) activity from surface electrodes placed over the tonically-activated sternocleidomastoid (SCM) muscles. The "cervical VEMP" (cVEMP) is thus a manifestation of the vestibulo-collic reflex. However, recent research has shown that VEMPs can also be recorded from the extraocular muscles using surface electrodes placed near the eyes. These "ocular VEMPs" (oVEMPs) are a manifestation of the vestibulo-ocular reflex. Here we describe the historical development and neurophysiological properties of the cVEMP and oVEMP and provide recommendations for recording both reflexes. While the cVEMP has documented diagnostic utility in many disorders affecting vestibular function, relatively little is known as yet about the clinical value of the oVEMP. We therefore outline the known cVEMP and oVEMP characteristics in common central and peripheral disorders encountered in neuro-otology clinics.
Corrigendum to A utricular origin of frequency tuning to low-frequency vibration in the human vestibular system? [Neurosci. Lett. 451 (2009) 175-180] (DOI:10.1016/j.neulet.2008.12.055)
Publisher: Elsevier BV
Date: 04-2009
Vestibular evoked myogenic potentials evoked by brief interaural head acceleration: Properties and possible origin
Publisher: American Physiological Society
Date: 09-2009
DOI: 10.1152/JAPPLPHYSIOL.00296.2009
Abstract: The vestibular system responds to head acceleration by producing compensatory reflexes in the eyes and postural muscles. In this study, we investigated the effect of brief interaural acceleration on the vestibular evoked myogenic potential (VEMP) in 10 normal subjects and 10 patients with bilateral (bVL) or unilateral vestibular loss (uVL). The stimuli were delivered with a handheld minishaker and tendon hammer over the mastoid and produced relatively pure interaural head acceleration with little rotation (mean peak acceleration: 0.14 g at 3.3 ms). VEMPs were recorded from the neck muscles and were characterized in normal subjects by a positive/negative potential ipsilateral to the stimulated side (peak latencies: 15.1 and 22.6 ms) and a positive response contralaterally (20.3 ms), which was sometimes preceded by a negativity (14.5 ms). These peaks were absent in patients with bVL, confirming their vestibular dependence. In the patients with uVL, medial acceleration of the intact ear produced bilateral responses, an initial positivity on the intact side, and a negativity on the affected side, whereas lateral acceleration produced only a late positivity on the intact side. As the acceleration was primarily in the horizontal plane, it is likely to have activated utricular receptors. Consistent with this, we found that VEMPs are very sensitive to the direction of head acceleration and have features consistent with the utriculocollic projections demonstrated in animals.
Repetitive ocular vestibular evoked myogenic potential stimulation for the diagnosis of myasthenia gravis: Optimization of stimulation parameters
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.CLINPH.2019.03.033
Abstract: To determine the most effective stimulation parameters for the diagnosis of ocular myasthenia gravis (MG) using repetitive ocular vestibular evoked myogenic potentials (oVEMP) for quantification of the extraocular muscle response decrement. Repetitive bone-conducted oVEMPs were elicited in 18 MG patients and 20 healthy subjects. We compared four different stimulus repetition rates (20 Hz, 30 Hz, 40 Hz, 50 Hz) and 100 Hz continuous stimulation, as well as recordings from the inferior oblique muscles and the lateral rectus muscles to determine the most sensitive and specific oVEMP parameters for decrement detection. Repetitive stimulation at all tested repetition rates with recordings from inferior oblique muscles allowed for effective differentiation between MG patients and healthy subjects. Among all repetition rates, 30 Hz showed a trend towards superiority, with a sensitivity of 71% and a specificity of 94% (area under the curve (AUC) 0.88) when using the smaller decrement of the two eyes and -10% as cutoff. Considering the larger decrement for analysis (-9% as cutoff), sensitivity increased to 82%, but specificity decreased to 78% (AUC 0.81). Our study demonstrates, that repetitive oVEMP stimulation elicits a robust decrement in the inferior oblique muscles of MG patients at repetition rates between 20 Hz and 50 Hz, with a probable optimum at 30 Hz. Repetitive inferior oblique oVEMP stimulation with optimal stimulus parameters facilitates early and accurate diagnosis of ocular MG.
Vestibular evoked myogenic potentials in practice: Methods, pitfalls and clinical applications
Publisher: Elsevier BV
Date: 2019
Clinical Utility of Ocular Vestibular-Evoked Myogenic Potentials (oVEMPs)
Publisher: Springer Science and Business Media LLC
Date: 15-03-2015
DOI: 10.1007/S11910-015-0548-Y
Abstract: Over the last years, vestibular-evoked myogenic potentials (VEMPs) have been established as clinical tests of otolith function. Complementary to the cervical VEMPs, which assess mainly saccular function, ocular VEMPs (oVEMPs) test predominantly utricular otolith function. oVEMPs are elicited either with air-conducted (AC) sound or bone-conducted (BC) skull vibration and are recorded from beneath the eyes during up-gaze. They assess the vestibulo-ocular reflex and are a crossed excitatory response originating from the inferior oblique eye muscle. Enlarged oVEMPs have proven to be sensitive for screening of superior canal dehiscence, while absent oVEMPs indicate a loss of superior vestibular nerve otolith function, often seen in vestibular neuritis (VN) or vestibular Schwannoma.
The effect of alcohol on cervical and ocular vestibular evoked myogenic potentials in healthy volunteers
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.CLINPH.2013.12.096
Abstract: We investigated the effect of alcohol on the cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs). As alcohol produces gaze-evoked nystagmus (GEN), we also tested the effect of nystagmus independent of alcohol by recording oVEMPs during optokinetic stimulation (OKS). The effect of alcohol was tested in 14 subjects over multiple rounds of alcohol consumption up to a maximum breath alcohol concentration (BrAC) of 1.5‰ (mean 0.97‰). The effect of OKS was tested in 11 subjects at 5, 10 and 15deg/sec. oVEMP litude decreased from baseline to the highest BrAC level by 27% (range 5-50%, P<0.001), but there was no significant effect on oVEMP latency or cVEMP litude or latency. There was a significant negative effect of OKS on oVEMP litude (16%, P=0.006). We found a selective effect of alcohol on oVEMP litude, but no effect on the cVEMP. Vertical nystagmus elicited by OKS reduced oVEMP litude. Alcohol selectively affects oVEMP litude. Despite the effects of alcohol and nystagmus, both reflexes were reliably recorded in all subjects and conditions. An absent response in a patient affected by alcohol or nystagmus indicates a vestibular deficit.
Ocular vestibular evoked myogenic potentials are abnormal in internuclear ophthalmoplegia
Publisher: Elsevier BV
Date: 06-2011
DOI: 10.1016/J.CLINPH.2010.10.040
Abstract: The 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 oVEMP is abnormal in patients with a lesion of the otolith-ocular pathway. We describe a patient who developed a right INO during his first episode of demyelination, and report results from 12 additional patients, most of whom had multiple sclerosis. All subjects were stimulated with air-conducted tone bursts. cVEMPs and oVEMPs were measured using surface electrodes placed over the neck and beneath the eyes. Overall, oVEMPs showed significantly more abnormalities (69%) than cVEMPs (8%). Ocular VEMPs were absent with stimulation of 13/26 ears, significantly delayed in 5/26 cases and normal in only 8/26 cases. Ocular VEMPs are often abnormal in patients with multiple sclerosis who have an INO, while cVEMPs are usually normal. Ocular VEMPs provide a new, non-invasive method for examining central vestibular pathways in humans and are sensitive to lesions of the MLF.
The effect of gaze direction on the ocular vestibular evoked myogenic potential produced by air-conducted sound
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.CLINPH.2009.04.017
Abstract: To 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. Ten normal subjects were stimulated by 500 Hz 2 ms AC tone bursts at 136-142 dB peak SPL. OVEMPs were recorded from electrodes placed beneath the eyes. Angles of vertical gaze ranged from maximal downward to upward gaze in increments of 5-10 degrees . Horizontal gaze was measured during elevation and ranged from 20 degrees adduction to 20 degrees abduction. Increasing vertical gaze increased OVEMP litude, especially for the contralateral eye (neutral vs maximal upward gaze contra: 1.0 vs 2.6 microV ipsi: 0.8 vs 0.9 microV P<0.001). OVEMPs from the contralateral eye peaked significantly earlier in the upward gaze positions (contra: 9.2 ms ipsi: 10.4 ms P<0.001), but peaked later during downward gaze (contra: 14.2 ms ipsi: 11.4 ms P=0.014). There were small effects of horizontal gaze and supine body position, but no effects of head rotation or vision. OVEMP litudes are strongly modulated by gaze position. Truncal position also affects OVEMP litude. This study quantifies the effect of gaze on the OVEMP and demonstrates the importance of controlling for gaze in clinical and experimental studies.
cVEMP morphology changes with recording electrode position, but single motor unit activity remains constant
Publisher: American Physiological Society
Date: 15-04-2016
DOI: 10.1152/JAPPLPHYSIOL.00917.2015
Abstract: Cervical vestibular evoked myogenic potentials (cVEMPs) recorded over the lower quarter of the sternocleidomastoid (SCM) muscle in normal subjects may have opposite polarity to those recorded over the midpoint. It has thus been suggested that vestibular projections to the lower part of SCM might be excitatory rather than inhibitory. We tested the hypothesis that the SCM muscle receives both inhibitory and excitatory vestibular inputs. We recorded cVEMPs in 10 normal subjects with surface electrodes placed at multiple sites along the anterior (sternal) component of the SCM muscle. We compared several reference sites: sternum, ipsilateral and contralateral earlobes, and contralateral wrist. In five subjects, single motor unit responses were recorded at the upper, middle, and lower parts of the SCM muscle using concentric needle electrodes. The surface cVEMP had the typical positive-negative polarity at the midpoint of the SCM muscle. In all subjects, as the recording electrode was moved toward each insertion point, p13 litude became smaller and p13 latency increased, then the polarity inverted to a negative-positive waveform (n1-p1). Changing the reference site did not affect reflex polarity. There was a significant short-latency change in activity in 61/63 single motor units, and in each case this was a decrease or gap in firing, indicating an inhibitory reflex. Single motor unit recordings showed that the reflex was inhibitory along the entire SCM muscle. The cVEMP surface waveform inversion near the mastoid and sternal insertion points likely reflects volume conduction of the potential occurring with increasing distance from the motor point.
μVEMP: A portable interface to record vestibular evoked myogenic potentials (VEMPs) with a smart phone or tablet
Publisher: Frontiers Media SA
Date: 05-07-2018
Contrasting phase effects on vestibular evoked myogenic potentials (VEMPs) produced by air- and bone-conducted stimuli
Publisher: Springer Science and Business Media LLC
Date: 24-09-2016
DOI: 10.1007/S00221-015-4441-3
Abstract: We have studied the effects of stimulus phase on the latency and litude of cVEMPs and oVEMPs by reanalysing data from Lim et al. (Exp Brain Res 224:437-445, 2013) in which alternating phase was used. Responses for the different initial stimulus phase, either positive or negative, were separated and reaveraged. We found that the phase (compressive or rarefactive) of AC 500-Hz stimuli had no significant effect on either latency or litude of the responses. Conversely, phase (positive = motor towards subjects) did alter the effects of BC 500-Hz stimulation. For cVEMPs, phase consistently affected initial latency with earlier responses for positive stimuli, while, for stimulation at the mastoid, negative onset phase gave larger responses. For the oVEMP, effects were different for the two sites of BC stimulation. At the forehead, the response appeared to invert, whereas at the mastoid there appeared to be a delay of the initial response. Related to this, the effect of phase for the two sites was opposite: at the mastoid, positive responses were earlier but negative were larger (particularly for long stimuli). At the forehead, the effect was the opposite: negative onset stimuli evoked earlier responses, whereas positive onset evoked larger responses. These findings indicate a basic difference in the way that AC and BC stimuli activate vestibular receptors and also indicate that the effects of phase of BC stimulation depend on location. Stimulus alternation does little to affect the response to AC stimulation but obscures the effects of BC stimuli, particularly for the oVEMP.
Single motor unit responses underlying cervical vestibular evoked myogenic potentials produced by bone-conducted stimuli
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.CLINPH.2014.07.037
Abstract: Cervical vestibular evoked myogenic potentials (cVEMPs) are muscle reflexes recorded from the sternocleidomastoid (SCM) neck muscles following vestibular activation with air- or bone-conducted (BC) stimulation. We investigated the effect of different forms of BC stimulation on the single motor unit response underlying the cVEMP. We tested 8 healthy human subjects with 5 different stimuli. Motor units were recorded with thin concentric needle electrodes surface potentials were recorded simultaneously. The polarity of the initial change (at approx. 15 ms) in single motor unit activity reflected the polarity of the surface cVEMPs: a short-latency decrease in activity (inhibition) was seen with the four stimuli that produced a positive surface potential (p13), while an initial increase in activity (excitation) was seen with the stimulus that produced a negative surface potential. BC stimulation with common clinical stimuli usually produces an inhibition in single motor unit activity in the ipsilateral SCM muscle. However the projections activated by BC stimulation are not exclusively inhibitory in nature and depend upon the shape and direction of the stimulus. The utricle is likely to contribute to some BC cVEMPs, as some stimuli clearly evoke an excitation that is not likely to be saccular in origin.
Vestibular-evoked extraocular potentials produced by stimulation with bone-conducted sound
Publisher: Elsevier BV
Date: 08-2005
DOI: 10.1016/J.CLINPH.2005.03.019
Abstract: To investigate the origin, whether ocular or extraocular, of the short latency frontal potential (N15) reported by following vestibular stimulation. Fourteen subjects with low VEMP thresholds (V(T)) and 9 patients with vestibular or ocular disorders were stimulated at the mastoid with bone-conducted tone bursts (500 Hz, 8 ms) above vestibular threshold, using a B71 bone vibrator. Surface potentials were recorded from Fpz and around the eyes and referred to linked earlobes. The N15 was present at Fpz, but was largest around the eyes (mean litude 2.6 microV, peak latency 13.4 ms, with stimulation at +18 dB above threshold) and was generally in phase above and below the eyes. The response was vestibular-dependent and modulated by alteration of gaze direction. The potentials were delayed in a patient with Miller Fisher syndrome and were larger in patients with superior canal dehiscence than in controls. We report a new vestibular-evoked extraocular potential. Its properties are not consistent with an eye movement. It is likely to be produced, mainly or exclusively, by synchronous activity in extraocular muscles (i.e. a myogenic potential). Vestibular-evoked extraocular potentials extend the range of vestibular pathways that can be assessed electrophysiologically, and may be a useful additional test of vestibular function.
Bone-conducted vestibular and stretch reflexes in human neck muscles
Publisher: Springer Science and Business Media LLC
Date: 11-04-2020
Bone-Conducted oVEMP Latency Delays Assist in the Differential Diagnosis of Large Air-Conducted oVEMP Amplitudes
Publisher: Frontiers Media SA
Date: 29-10-2020
Sound-evoked vestibular projections to the splenius capitis in humans: comparison with the sternocleidomastoid muscle
Publisher: American Physiological Society
Date: 06-2019
DOI: 10.1152/JAPPLPHYSIOL.00711.2018
Abstract: The short-latency vestibulo-collic reflex in humans is well defined for only the sternocleidomastoid (SCM) neck muscle. However, other neck muscles also receive input from the balance organs and participate in neck stabilization. We therefore investigated the sound-evoked vestibular projection to the splenius capitis (SC) muscles by comparing surface and single motor unit responses in the SC and SCM muscles in 10 normal volunteers. We also recorded surface responses in patients with unilateral vestibular loss but preserved hearing and hearing loss but preserved vestibular function. The single motor unit responses were predominantly inhibitory, and the strongest responses were recorded in the contralateral SC and ipsilateral SCM. In both cases there was a significant decrease or gap in single motor unit activity, in SC at 11.7 ms for 46/66 units and in SCM at 12.7 ms for 51/58 motor units. There were fewer significant responses in the ipsilateral SC and contralateral SCM muscles, and they consisted primarily of weak increases in activity. Surface responses recorded over the contralateral SC were positive-negative during neck rotation, similar to the ipsilateral cervical vestibular evoked myogenic potential in SCM. Responses in SC were present in the patients with hearing loss and absent in the patient with vestibular loss, confirming their vestibular origin. The results describe a pattern of inhibition consistent with the synergistic relationship between these muscles for axial head rotation, with the crossed vestibular projection to the contralateral SC being weaker than the ipsilateral projection to the SCM. NEW & NOTEWORTHY We used acoustic vestibular stimulation to investigate the saccular projections to the splenius capitis (SC) and sternocleidomastoid (SCM) muscles in humans. Single motor unit recordings from within the muscles demonstrated strong inhibitory projections to the contralateral SC and ipsilateral SCM muscles and weak excitatory projections to the opposite muscle pair. This synergistic pattern of activation is consistent with a role for the reflex in axial rotation of the head.
Ocular vestibular evoked myogenic potentials (OVEMPs) produced by impulsive transmastoid accelerations
Publisher: Elsevier BV
Date: 07-2008
DOI: 10.1016/J.CLINPH.2008.03.009
Abstract: Recent 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. Accelerometry was measured in 4 subjects in response to acceleration impulses produced by a gamma function delivered with a Minishaker (4810, Bruel & Kjaer). This stimulus produced peak head accelerations of 0.13-0.14 g occurring at between 3.1 and 4.0 ms at the mastoids for both right and left head movement. OVEMPs were recorded in 10 normal subjects with 5 directions of gaze, using electrode pairs placed lateral to, above and below the eyes. OVEMPs occurred at short latency, with initial peaks between 10.3 ms (p10) and 15.3 ms (n15). For a given recording site and gaze direction, the responses were determined solely by the direction of imposed acceleration. We propose that, given the transtemporal nature of the stimuli, utricular afferents are likely to be powerfully activated. The OVEMPs evoked may be generated by the lateral recti and oblique muscles. Sudden lateral accelerations of the head evoke the translational VOR and ocular counter rolling reflex and the pattern of muscle activations indicated by the OVEMPs appear to be a manifestation of these reflexes.
Cervical and Ocular Vestibular Evoked Myogenic Potentials Are Sensitive to Stimulus Phase
Publisher: S. Karger AG
Date: 11-12-2010
DOI: 10.1159/000321988
Abstract: Sinusoidal forces with frequencies of 100 and 500 Hz and initial positive or negative polarities were delivered to the mastoids and Fz in normal subjects. We investigated whether the cVEMPs and oVEMPs evoked were sensitive to the polarity (phase) of vibration. With mastoid stimulation at 100 Hz, medial head acceleration produced cVEMPs with earlier latency (15.5 ms) than lateral acceleration (19.7 ms) and oVEMPs with later latency (13.8 ms) than lateral acceleration (10.6 ms). As the stimulus frequency increased, the difference in latency decreased, but was still present at 500 Hz. A similar pattern occurred following stimulation at Fz. Our results show that the initial direction of bone-conducted vibration affects both cVEMP and oVEMP properties even at relatively high frequencies.
New perspectives on vestibular evoked myogenic potentials
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2013
Investigating short latency subcortical vestibular projections in humans: what have we learned?
Publisher: American Physiological Society
Date: 11-2019
Abstract: Vestibular evoked myogenic potentials (VEMPs) are now widely used for the noninvasive assessment of vestibular function and diagnosis in humans. This review focuses on the origin, properties, and mechanisms of cervical VEMPs and ocular VEMPs how these reflexes relate to reports of vestibular projections to brain stem and cervical targets and the physiological role of (otolithic) cervical and ocular reflexes. The evidence suggests that both VEMPs are likely to represent the effects of excitation of irregularly firing otolith afferents. While the air-conducted cervical VEMP appears to mainly arise from excitation of saccular receptors, the ocular VEMP evoked by bone-conducted stimulation, including impulsive bone-conducted stimuli, mainly arises from utricular afferents. The surface responses are generated by brief changes in motor unit firing. The effects that have been demonstrated are likely to represent otolith-dependent vestibulocollic and vestibulo-ocular reflexes, both linear and torsional. These observations add to previous reports of short latency otolith projections to the target muscles in the neck (sternocleidomastoid and splenius) and extraocular muscles (the inferior oblique). New insights have been provided by the investigation and application of these techniques.
Ocular vestibular evoked myogenic potentials produced by impulsive lateral acceleration in unilateral vestibular dysfunction
Publisher: Elsevier BV
Date: 12-2011
DOI: 10.1016/J.CLINPH.2011.04.024
Abstract: To 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. OVEMPs were recorded using lateral impulsive stimuli delivered by a hand-held minishaker placed at the mastoid. Twelve patients were tested using the typical OVEMP recording montage placed inferior to the eyes. In a subset of 6 patients, recordings were also made using a lateral electrode montage. The majority of patients were tested following surgery for inner ear disease. Patient responses were compared to those in normal subjects under similar recording conditions. For the inferior montage, regardless of which mastoid was stimulated, deficits were observed only from the eye opposite the affected ear. In contrast, OVEMPs recorded using the lateral electrode montage showed changes on both sides. OVEMPs produced using lateral transmastoid stimulation and recorded from beneath the eyes are generated by a crossed vestibulo-ocular pathway while the projections underlying the lateral responses are likely to be bilateral. The vestibular-ocular connectivity underlying the OVEMPs recorded from inferior and lateral recording sites differs. For clinical use, the inferior recording site is the simplest to interpret.
Subjective visual horizontal correlates better with ocular than with cervical vestibular evoked myogenic potentials
Publisher: Elsevier BV
Date: 08-2023
Investigating the causal effect of smoking on hay fever and asthma: a Mendelian randomization meta-analysis in the CARTA consortium
Publisher: Springer Science and Business Media LLC
Date: 22-05-2017
DOI: 10.1038/S41598-017-01977-W
Abstract: Observational studies on smoking and risk of hay fever and asthma have shown inconsistent results. However, observational studies may be biased by confounding and reverse causation. Mendelian randomization uses genetic variants as markers of exposures to examine causal effects. We examined the causal effect of smoking on hay fever and asthma by using the smoking-associated single nucleotide polymorphism (SNP) rs16969968/rs1051730. We included 231,020 participants from 22 population-based studies. Observational analyses showed that current vs never smokers had lower risk of hay fever (odds ratio (OR) = 0·68, 95% confidence interval (CI): 0·61, 0·76 P 0·001) and allergic sensitization (OR = 0·74, 95% CI: 0·64, 0·86 P 0·001), but similar asthma risk (OR = 1·00, 95% CI: 0·91, 1·09 P = 0·967). Mendelian randomization analyses in current smokers showed a slightly lower risk of hay fever (OR = 0·958, 95% CI: 0·920, 0·998 P = 0·041), a lower risk of allergic sensitization (OR = 0·92, 95% CI: 0·84, 1·02 P = 0·117), but higher risk of asthma (OR = 1·06, 95% CI: 1·01, 1·11 P = 0·020) per smoking-increasing allele. Our results suggest that smoking may be causally related to a higher risk of asthma and a slightly lower risk of hay fever. However, the adverse events associated with smoking limit its clinical significance.
Vestibular-Evoked Myogenic Potentials in Bilateral Vestibulopathy
Publisher: Frontiers Media SA
Date: 17-04-2018
Galvanic ocular vestibular evoked myogenic potentials provide new insight into vestibulo-ocular reflexes and unilateral vestibular loss
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.CLINPH.2008.12.001
Abstract: Synchronous 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. We stimulated 10 normals and 6 patients with unilateral vestibular loss (uVL) with bi/unipolar 4 mA, 2 ms current steps at the mastoid. OVEMPs were recorded from electrodes placed superior and inferior to the eyes. OVEMPs were present beneath both eyes in all normal subjects: an initial positivity ipsilateral to the cathodal electrode (peak latency 9.9 ms, litude 1.3 microV) and an initial negativity contralateral to the cathode (8.8 ms, 2.4 microV). In the patients, stimulation of the affected side produced little or no response. Stimulation of the intact side produced only contralateral responses. The infra-orbital response is likely produced primarily by the inferior obliques, producing conjugate torsion away from the cathode. The projection to the ipsilateral eye depends upon normal vestibular function on the contralateral side. OVEMPs can be evoked by GVS. While bilateral effects are obtained with unilateral stimulation in normals, the primary vestibular pathway to the inferior oblique in humans is crossed.
Tuning and sensitivity of the human vestibular system to low-frequency vibration
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.NEULET.2008.08.011
Abstract: Mechanoreceptive hair-cells of the vertebrate inner ear have a remarkable sensitivity to displacement, whether excited by sound, whole-body acceleration or substrate-borne vibration. In response to seismic or substrate-borne vibration, thresholds for vestibular afferent fibre activation have been reported in anamniotes (fish and frogs) in the range -120 to -90 dB re 1g. In this article, we demonstrate for the first time that the human vestibular system is also extremely sensitive to low-frequency and infrasound vibrations by making use of a new technique for measuring vestibular activation, via the vestibulo-ocular reflex (VOR). We found a highly tuned response to whole-head vibration in the transmastoid plane with a best frequency of about 100 Hz. At the best frequency we obtained VOR responses at intensities of less than -70 dB re 1g, which was 15 dB lower than the threshold of hearing for bone-conducted sound in humans at this frequency. Given the likely synaptic attenuation of the VOR pathway, human receptor sensitivity is probably an order of magnitude lower, thus approaching the seismic sensitivity of the frog ear. These results extend our knowledge of vibration-sensitivity of vestibular afferents but also are remarkable as they indicate that the seismic sensitivity of the human vestibular system exceeds that of the cochlea for low-frequencies.
Differential effect of current rise time on short and medium latency vestibulospinal reflexes
Publisher: Elsevier BV
Date: 08-2002
DOI: 10.1016/S1388-2457(02)00121-9
Abstract: To investigate the effect of varying current rise time on galvanic-evoked short (SL) and medium (ML) latency vestibulospinal reflexes. We recorded the soleus EMG of standing subjects in response to 3 mA direct current transmastoid stimulation with a series of current r s with rise times of 0-300 ms. Longer current rise times significantly delayed the onset of both SL (P<<0.001) and ML (P<<0.001) vestibulospinal responses, by approximately 20 and 39 ms, respectively. The SL response litude was reduced with increasing rise time (P<<0.001), whereas the ML response litude was relatively unaffected by stimulus rise time. With very slow rise times a prolonged ML response alone was evoked. Both SL and ML reflexes can be evoked by changes in vestibular activity produced by transmastoid galvanic stimulation with a r onset. We found a differential effect of current rise time on SL and ML vestibulospinal reflexes, suggesting different potential functional roles for the two reflexes. SL reflexes can participate in the response to abrupt disturbances only. ML reflexes are evoked by both fast and slow changes in vestibular discharge and may be particularly effective for slowly-changing disturbances.
Effects of muscle contraction on cervical vestibular evoked myogenic potentials in normal subjects
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.CLINPH.2014.12.027
Abstract: Cervical vestibular evoked myogenic potentials (cVEMPs) are vestibular-dependent muscle reflexes recorded from the sternocleidomastoid (SCM) muscles in humans. cVEMP litude is modulated by stimulus intensity and SCM muscle contraction strength, but the effect of muscle contraction is less well-documented. The effects of intensity and contraction were therefore compared in 25 normal subjects over a wide range of contractions. cVEMPs were recorded at different contraction levels while holding stimulus intensity constant and at different intensities while holding SCM contraction constant. The effect of muscle contraction on cVEMP litude was linear for most of the range of muscle contractions in the majority of subjects (mean R(2)=0.93), although there were some nonlinearities when the contraction was either very weak or very strong. Very weak contractions were associated with absent responses, incomplete morphology and prolonged p13 latencies. Normalization of litudes, by iding the p13-n23 litude by the muscle contraction estimate, reduced the effect of muscle contraction, but tended to underestimate the litude with weak contractions. Minimum contraction levels are required for accurate interpretation of cVEMPs. These data highlight the importance of measuring SCM contraction strength when recording cVEMPs.
Disorders of the inner-ear balance organs and their pathways
Publisher: Elsevier
Date: 2018
Why do oVEMPs become larger when you look up? Explaining the effect of gaze elevation on the ocular vestibular evoked myogenic potential
Publisher: Elsevier BV
Date: 04-2013
DOI: 10.1016/J.CLINPH.2012.10.012
Abstract: The ocular vestibular evoked myogenic potential (oVEMP) is a vestibular reflex recorded from the inferior oblique (IO) muscles, which increases in litude during eye elevation. We investigated whether this effect of gaze elevation could be explained by movement of the IO closer to the recording electrode. We compared oVEMPs recorded with different gaze elevations to those recorded with constant gaze position but electrodes placed at increasing distance from the eyes. oVEMPs were recorded in ten healthy subjects using bursts of skull vibration. oVEMP litude decreased more with decreasing gaze elevation (9 μV from 24° up to neutral) than with increasing electrode distance (2.7 μV from baseline to 6.4 mm P<0.005). The oVEMP recorded with gaze 24° down had delayed latency (by 4.5 ms). The effect of gaze elevation on the oVEMP cannot be explained by changes in position of the muscle alone and is likely mainly due to increased tonic contraction of the IO muscle in up-gaze. The oVEMP recorded in down-gaze (when the IO is inactivated, but the IR activated) likely originates in the adjacent IR muscle. Our results suggest that oVEMP litudes in extraocular muscles scale in response to changing tonic muscle activity.
Subjective Cognitive Dysfunction in Patients with Dizziness and Vertigo
Publisher: S. Karger AG
Date: 10-09-2022
DOI: 10.1159/000518188
Abstract: b i Introduction: /i /b Patients with vestibular disorders sometimes report cognitive difficulties, but there is no consensus about the type or degree of cognitive complaint. We therefore investigated subjective cognitive dysfunction in a well-defined s le of neuro-otology patients and used demographic factors and scores from a measure of depression, anxiety, and stress to control for potential confounding factors. b i Methods: /i /b We asked 126 neuro-otology clinic outpatients whether they experienced difficulties with thinking, memory, or concentration as a result of dizziness or vertigo. They and 42 nonvertiginous control subjects also completed the Neuropsychological Vertigo Inventory (NVI, which measures cognitive, emotional, vision, and motor complaints), the Everyday Memory Questionnaire (EMQ), and Depression, Anxiety, and Stress Scales (DASS). b i Results: /i /b In the initial interview questions, 60% of patients reported experiencing cognitive difficulties. Cognitive questionnaire scores were positively correlated with the overall DASS score and to a lesser extent with age and gender. Therefore, we compared patients and controls on the NVI and EMQ, using these mood and demographic variables as covariates. Linear regression analyses revealed that patients scored significantly worse on the total NVI, NVI cognitive composite, and 3 in idual NVI cognition subscales (Attention, Space Perception, and Time Perception), but not the EMQ. Patients also scored significantly worse on the NVI Emotion and Motor subscales. b i Conclusions: /i /b Patients with dizziness and vertigo reported high levels of cognitive dysfunction, affecting attention, perceptions of space and time. Although perceptions of cognitive dysfunction were correlated with emotional distress, they were significantly elevated in patients over and above the impact of depression, anxiety, or stress.
Delayed vestibular evoked responses to the eyes and neck in a patient with an isolated brainstem lesion
Publisher: Elsevier BV
Date: 09-2007
DOI: 10.1016/J.CLINPH.2007.05.068
Abstract: Two recently described tests of the vestibular system, vestibular evoked myogenic potentials (VEMPs) and ocular vestibular evoked myogenic potentials (OVEMPs), test the descending and ascending vestibular brainstem pathways, respectively. We describe a case of a patient in whom these investigations localised the lesion and suggested its nature. VEMPs (to clicks and short duration galvanic stimulation) and OVEMPs (to clicks) were recorded. Click- and galvanic-evoked VEMPs were delayed on the left side (by approximately 5-6 ms), and click-evoked OVEMPs were similarly delayed (by approximately 4 ms) following left-sided stimulation. Repeat testing 21 months later showed partial resolution. The observed delays in evoked potentials suggested a demyelinating lesion. Furthermore, the similarity in delayed responses to neck and extraocular muscles was suggestive of a lesion at the root entry zone of the vestibulocochlear nerve. VEMPs and OVEMPS may thus provide information about the location and nature of lesions affecting central vestibular pathways.
Vestibular-Evoked Myogenic Potential Testing in Vestibular Localization and Diagnosis
Publisher: Georg Thieme Verlag KG
Date: 14-01-2020
Abstract: Vestibular-evoked myogenic potentials (VEMPs) are short-latency, otolith-dependent reflexes recorded from the neck and eye muscles. They are widely used in neuro-otology clinics as tests of otolith function. Cervical VEMPs are recorded from the neck muscles and reflect predominantly saccular function, while ocular VEMPs are reflexes of the extraocular muscles and reflect utricular function. They have an important role in the diagnosis of superior canal dehiscence syndrome and provide complementary information about otolith function that is useful in the diagnosis of other vestibular disorders. Like other evoked potentials, they can provide important localizing information about lesions that may occur along the VEMP pathway. This review will describe the VEMP abnormalities seen in common disorders of the vestibular system and its pathways.
Ocular vestibular evoked myogenic potentials in superior canal dehiscence
Publisher: BMJ
Date: 05-2008
Abstract: 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- litude, low-threshold responses in SCD, and could differentiate patients with SCD from normal control patients. Nine patients with CT-confirmed SCD and 10 normal controls were stimulated with 500 Hz, 2 ms tone bursts and 0.1 ms clicks at intensities up to 142 dB peak SPL. Conventional VEMPs were recorded from the ipsilateral sternocleidomastoid muscle to determine threshold, and OVEMPs were recorded from electrode pairs placed superior and inferior to the eyes. Three-dimensional eye movements were measured with scleral dual-search coils. In patients with SCD, OVEMP litudes were significantly larger than normal (p<0.001) and thresholds were pathologically low. The n10 OVEMP in the contralateral inferior electrode became particularly large with increasing stimulus intensity (up to 25 microV) and with up-gaze (up to 40 microV). Sound-evoked (slow-phase) eye movements were present in all patients with SCD (vertical: upward torsional: upper pole away from the affected side and horizontal: towards or away from the affected side), but began only as the OVEMP response became maximal, which is consistent with the surface potentials being produced by activation of the extraocular muscles that generated the eye movements. OVEMP litude and threshold (particularly the contralateral inferior n10 response) differentiated patients with SCD from normal controls. Our findings suggest that both the OVEMPs and induced eye movements in SCD are a result of intense saccular activation in addition to superior canal stimulation.
Low-frequency tuning in the human vestibular-ocular projection is determined by both peripheral and central mechanisms
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.NEULET.2009.04.014
Abstract: We recently reported that a major contribution to the low-frequency tuning and sensitivity of the human vestibular system is the biomechanical properties of the vestibular end-organs. In the current paper, we investigate the contribution of additional mechanisms to low-frequency tuning. We compared the response properties of the vestibular system in 6 human volunteers to trains of 2 ms pulses of sound and transmastoid vibration using pulse repetition frequencies of 12.5, 25, 50, 100, 200 and 400 Hz. Measurements were made using two separate pathways arising from the vestibular apparatus: to the neck using vestibular evoked myogenic potentials (VEMPs), and to the eyes using ocular vestibular evoked myogenic potentials (OVEMPs). For both sound and vibration the two response pathways produced different tuning to pulse trains. The vestibulo-ocular pathway was characterised by a band-pass tuning with best frequency of 100 Hz whereas the vestibulo-collic pathway showed a peak at 400 Hz with sound only. These results suggest that properties of the vestibulo-ocular pathway also contribute to the low-frequency tuning that occurs for the OVEMP, in addition to previously reported end-organ effects.
Vestibular evoked myogenic potentials are intact in cervical dystonia
Publisher: Wiley
Date: 19-10-2010
DOI: 10.1002/MDS.23422
Abstract: Vestibular dysfunction has been reported in patients with cervical dystonia (CD), but it is still unclear whether the abnormalities occur as part of the CD syndrome or whether they arise from the abnormal posture and movement of the head. We compared vestibular-evoked myogenic potentials (VEMPs) recorded from the affected neck muscles (i.e., cervical VEMPs) with those recorded from muscles unaffected by the dystonia, the extraocular muscles (i.e., ocular VEMPs). We compared 21 patients and age-matched normal controls to investigate whether these short-latency reflexes are altered in CD. We also measured subjective visual horizontal (SVH). Seven patients had not received botulinum toxin treatment (naïve group), 10 were receiving regular injections (treatment group), and four had previously received treatment but had developed antibodies (antibody group). Both cervical and ocular VEMPs were present in the majority of patients and controls. For both reflexes, there were no significant differences between stimulation of the two sides of the head, between the treatment groups, or between the patients and controls. There was also no difference in degree of deviation of SVH between the groups. Our results showed that VEMPs can be reliably recorded from both the neck and extraocular muscles in patients with CD, even after long disease or treatment durations, and provide evidence for intact short-latency vestibular reflexes in CD.
Ocular vestibular evoked myogenic potentials as a test for myasthenia gravis
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 20-01-2016
Single motor unit activity in human extraocular muscles during the vestibulo‐ocular reflex
Publisher: Wiley
Date: 24-05-2012
Laboratory examinations for the vestibular system
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2018
A utricular origin of frequency tuning to low-frequency vibration in the human vestibular system?
Publisher: Elsevier BV
Date: 02-2009
DOI: 10.1016/J.NEULET.2008.12.055
Abstract: Recent work has demonstrated that the human vestibular system displays a remarkable sensitivity to low-frequency vibration. To address the origin of this sensitivity we compared the frequency response properties of vestibular reflexes to 10ms bursts of air-conducted sound and transmastoid vibration, which are thought to be differentially selective for the saccule and utricle, respectively. Measurements were made using two separate central pathways: vestibular evoked myogenic potentials (VEMPs), which are a manifestation of vestibulo-collic projections, and ocular vestibular evoked myogenic potentials (OVEMPs), which are a manifestation of vestibulo-ocular projections. For both response pathways air-conducted sound and vibration stimuli produced the same patterns of quite different tuning. Sound was characterised by a band-pass tuning with best frequency between 400 and 800Hz whereas vibration showed a low-pass type response with a largest response at 100Hz. Our results suggest that the tuning is at least in part due to properties of end-organs themselves, while the 100Hz best frequency may be a specifically utricular feature.
Two distinct patterns of VEMP changes with age
Publisher: Elsevier BV
Date: 10-2013
Ocular vestibular evoked myogenic potentials (OVEMPs) produced by air- and bone-conducted sound
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.CLINPH.2006.09.025
Abstract: To determine the origin and properties of short latency extraocular potentials produced by activation of the vestibular apparatus using two modes of acoustic stimulation. Extraocular potentials were measured in 10 normal subjects using a bipolar montage to increase selectivity. Three dimensional eye movements were also recorded in five subjects. The subjects were stimulated with both air-conducted (AC) and bone-conducted (BC) sound using a single cycle of a 500Hz sine wave. Short latency positive and negative potentials that peaked at 8.1-12.7ms for AC and 7.5-13.9ms for BC stimulation were recorded, which were distinct for the two eyes and for the two modes of stimulation. The extraocular potentials began prior to the onset of eye movements, which peaked at 16.5-20.1ms for AC, 17.8-25.0ms for BC stimulation. The pattern of short latency eye movements and extraocular potentials induced by AC and BC vestibular stimulation are distinct. As the potentials preceded the eye movements and were not correlated morphologically with them, the source of the observed potentials is not an eye movement and thus we refer to them as ocular vestibular evoked myogenic potentials (OVEMPs). The potentials had properties consistent with modulation of the electromyogenic activity of the extraocular muscles and if interpreted as originating from displacement of the eye will give misleading results. AC and BC acoustic stimulation are likely to activate differing profiles of vestibular end organs.
Vestibular-evoked myogenic potentials
Publisher: Elsevier
Date: 2016
The Contributions of Vestibular Evoked Myogenic Potentials and Acoustic Vestibular Stimulation to Our Understanding of the Vestibular System
Publisher: Frontiers Media SA
Date: 29-06-2018
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