Normal Vestibular Evoked Myogenic Potential Research Articles

Vestibular-Evoked Myogenic Potential (VEMP) in the Evaluation of Schistosomal Myeloradiculopathy

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

Topographical correlations of lateral medullary infarction with caloric- and vestibular-evoked myogenic potential results

This study investigated the correlation of caloric- and vestibular-evoked myogenic potential (VEMP) results with topographical lesions of lateral medullary infarction. Five patients with lateral medullary infarction were enrolled in this study. Each patient underwent a battery of tests, including audiometry, caloric test, VEMP test, and magnetic resonance imaging (MRI) study. Gaze nystagmus was observed in four patients (80%), while abnormal pursuit, saccade, and optokinetic nystagmus tests were noted in all patients (100%). MRI demonstrated infarction at the ponto-medullary junction in one patient and upper medulla in one patient. Both patients revealed caloric areflexia and normal VEMPs. In contrast, another three patients with infarction at the middle inferior olive level, all displayed abnormal (including absent or delayed) VEMPs, and one patient showed caloric areflexia. Topographical correlations of lateral medullary infarction with caloric and VEMP tests reveal that caloric areflexia is possibly linked with rostrally located infarction, while absent or delayed VEMPs relate to caudally located infarction.

The diagnostic value of vestibular-evoked myogenic potential in patients with vestibular schwannoma

This study examined the diagnostic value of the vestibular-evoked myogenic potential (VEMP) in comparison with the caloric test in patients with vestibular schwannoma (VS). Data were retrospectively collected from 803 consecutive patients who visited our vertigo clinic and underwent vestibular tests. Amongst them, 78 patients were diagnosed as having untreated unilateral VS. VEMP was performed using click and short-tone burst stimulation. The caloric test was performed using ice water. The sensitivity and specificity of each test were evaluated. Of the 78 patients with VS, 63 had abnormal VEMPs as well as abnormal caloric responses. Of the 725 patients without VS, 382 had normal VEMPs and 416 had normal caloric responses. The sensitivity and specificity of VEMP were 80.8% (95% CI: 72.0-89.5%) and 52.7% (95% CI: 49.1-56.3%), respectively; those of the caloric test were 80.8% (95% CI: 72.0-89.5%) and 57.4% (95% CI: 53.8-61.0%), respectively. The sensitivity and specificity of VEMP and the caloric test showed no significant differences. In patients with VS, although the specificity of VEMP was not very high, its sensitivity was high and comparable to that of the caloric test.

Hallazgos de potenciales vestibulares miogénicos evocados en la esclerosis múltiple

Vestibular evoked myogenic potential (VEMP) elicited by acoustic stimulation, has been proposed in the assessment of vestibulospinal pathways. To research the clinical utility of VEMP on multiple sclerosis (MS). Forty-four individuals were evaluated (30 normal state and 14 had MS). The acoustic stimuli were short tone burst (1 kHz, 118 dBNa, rise-fall 1 ms, plateau 2 ms) presented through a supra-aural earphone. The stimulation rate was 5 stimuli per second. All the healthy subjects showed a normal VEMP response. In the MS group, abnormal VEMP was recorded among 92.8% of patients and normal in just one case. The P13-N23 increased of prolongation which was the most frequently alteration (57.1%), followed by absence of response among four (28.5%) cases. VEMP was considered a good method of diagnostic support of vestibulospinal tract in cases of MS.

Reversible Electrocochleographic Abnormalities in Superior Canal Dehiscence

Electrocochleography (ECoG) is often used in the evaluation of episodic vertigo, and abnormal findings are commonly thought to be due to endolymphatic hydrops. We have observed that a number of patients with abnormal ECoG were ultimately found to have superior semicircular canal dehiscence (SSCD). Therefore, we examined the electrocochleographic findings in a series of patients with documented SSCD. Retrospective case series. Academic medical center. Seven adult patients with unilateral SSCD and 4 patients with bilateral SSCD who underwent tympanic ECoG as part of a diagnostic or preoperative evaluation that also included vestibular-evoked myogenic potentials (VEMPs). Patients underwent audiometric testing, ECoG, VEMP, and high-resolution temporal bone computed tomography reformatted to optimally view the superior semicircular canal. Five patients underwent superior canal obliteration. Postoperative VEMP and ECoG were performed in 4 of these patients. Intraoperative continuous ECoG was performed in 1 patient. Summating potential to action potential (SP/AP) ratio on ECoG. Fourteen of 15 ears confirmed to have SSCD on computed tomographic imaging were found to have an elevated SP/AP ratio (defined as >0.40). In one patient with bilateral SSCD, the ear with the radiographically less severe dehiscence had an SP/AP ratio of 0.40, at the upper limit of normal, and a normal VEMP threshold. In all 4 patients who underwent obliteration of the dehiscent canal, and for whom postoperative test results were available, the SP/AP ratio normalized in the operated ear. In the 1 patient who underwent intraoperative ECoG, the SP/AP ratio normalized immediately after canal occlusion. An elevated SP/AP ratio seems to be a consistent finding in SSCD syndrome and, like the other abnormal audiometric and electrophysiologic findings associated with the syndrome, normalizes after surgical correction. Elevation of the SP/AP ratio has historically been associated with endolymphatic hydrops. The present findings expand the differential diagnosis of an abnormal ECoG and may shed light on the origin of an elevated summating potential.

Physiological and Morphological Assessment of the Saccule in Guinea Pigs After Noise Exposure

To investigate whether the saccule exhibits temporary or permanent functional loss resembling threshold shifts in auditory brainstem response (ABR) of guinea pigs following noise exposure. Randomly bred guinea pigs were divided into 3 groups: A (short-term noise exposure, 30 minutes, n = 15), B (long-term noise exposure, 40 hours, n = 9), and C (no noise exposure, n = 5). University hospital. All animals underwent vestibular-evoked myogenic potential (VEMP) and ABR tests. Chronological changes of VEMP and ABR responses following noise exposure were analyzed and compared. After audiovestibular function testing, animals were killed for morphological study with light and electron microscopy. In group A, temporary VEMP loss and ABR threshold shifts recovered 2 and 4 days, respectively, after short-term noise exposure, with an interval of 2 days earlier in the recovery of VEMPs than that of ABR thresholds. In contrast, in group B, 78% and 83% of the ears exhibited permanent VEMP loss and ABR threshold shifts, respectively, 10 days following long-term noise exposure. In group C, all animals showed normal VEMPs and ABRs throughout the study period. Light and electron microscopic studies confirmed that loss of VEMPs correlated with saccular lesion. The saccule can exhibit temporary or permanent functional loss resembling hearing threshold shifts in guinea pigs following noise exposure. Recovery of VEMP precedes restoration of hearing threshold after damage from short-term noise exposure. Conversely, permanent VEMP loss after long-term noise exposure may reflect permanent hearing threshold shifts.

Analysis of Vestibular Testing in Patients With Vestibular Schwannoma Based on the Nerve of Origin, the Localization, and the Size of the Tumor

We aimed to analyze the factors influencing caloric response and vestibular evoked myogenic potential (VEMP) in vestibular schwannoma. The subjects comprised 130 patients with unilateral vestibular schwannoma pathologically diagnosed by surgery. Caloric response and the amplitude and latency of VEMP were measured and analyzed based on the nerve of origin, localization, and size of the tumor. The tumors were classified into 3 types based on localization: intracanalicular, intermediate, and medial; and into 4 grades based on size: 9 mm or less, 10 to 19 mm, 20 to 29 mm, and 30 mm or greater. : Abnormal rates of caloric response and VEMP in patients with tumors arising from the superior vestibular nerve were not significantly different from those in patients with tumors of the inferior vestibular nerve. In the intermediate and medial type-but not in the intracanalicular type-a significant difference in tumor size was observed between patients with normal caloric response and those with canal paresis as also between patients with normal VEMP and those with abnormal VEMP. In patients with tumors that maximally measured 10 to 19 mm or of the intermediate type, the p- and n-wave latencies of VEMP were significantly prolonged compared with those in the normal opposite ear. 1) The nerve of origin of tumors cannot be predicted based on caloric response and VEMP. 2) In the intermediate and medial types, caloric response and the VEMP amplitude are significantly diminished in association with an increase in tumor size. 3) Prolonged VEMP latencies seem to be not only caused by tumor compression to the brainstem or vestibular spinal tract but also by tumor compression isolated to the inferior vestibular nerve.

A novel WFS1 mutation in a family with dominant low frequency sensorineural hearing loss with normal VEMP and EcochG findings

BackgroundLow frequency sensorineural hearing loss (LFSNHL) is an uncommon clinical finding. Mutations within three different identified genes (DIAPH1, MYO7A, and WFS1) are known to cause LFSNHL. The majority of hereditary LFSNHL is associated with heterozygous mutations in the WFS1 gene (wolframin protein). The goal of this study was to use genetic analysis to determine if a small American family's hereditary LFSNHL is linked to a mutation in the WFS1 gene and to use VEMP and EcochG testing to further characterize the family's audiovestibular phenotype.MethodsThe clinical phenotype of the American family was characterized by audiologic testing, vestibular evoked myogenic potentials (VEMP), and electrocochleography (EcochG) evaluation. Genetic characterization was performed by microsatellite analysis and direct sequencing of WFS1 for mutation detection.ResultsSequence analysis of the WFS1 gene revealed a novel heterozygous mutation at c.2054G>C predicting a p.R685P amino acid substitution in wolframin. The c.2054G>C mutation segregates faithfully with hearing loss in the family and is absent in 230 control chromosomes. The p.R685 residue is located within the hydrophilic C-terminus of wolframin and is conserved across species. The VEMP and EcochG findings were normal in individuals segregating the WFS1 c.2054G>C mutation.ConclusionWe discovered a novel heterozygous missense mutation in exon 8 of WFS1 predicting a p.R685P amino acid substitution that is likely to underlie the LFSNHL phenotype in the American family. For the first time, we describe VEMP and EcochG findings for individuals segregating a heterozygous WFS1 mutation.

前庭神経炎の臨床像と経過

The clinical picture and course of vestibular neuronitis (VN) were investigated in 53 cases encountered over the last 8 years and 9 months. Lesions of the vestibular nerve were evaluated by the caloric test and vestibular evoked myogenic potentials (VEMP); canal paresis (CP) with normal VEMP indicated superior VN, while CP with impaired VEMP indicated both superior and inferior VN. Among the 53 cases of VN evaluated, 37 had superior VN, 13 had superior and inferior VN, and the remaining 3 cases were labeled as undetermined. No case of inferior VN was found in our series. Functional recovery of the vestibular nerve was confirmed in half of the cases in whom the caloric test was repeated around 3 months later. The average duration of gaze nystagmus observed was 11.5 days, and that of positional nystagmus observed using a CCD camera was 6 months. On the other hand, the duration for which gaze nystagmus was observed in 50% of the cases (50% positive period) was 9.5 days, and the corresponding duration for positional nystagmus was 62 days. The difference in the average duration and 50% positive period is discussed.

Vestibular evoked myogenic potentials evoked by multichannel cochlear implant – influence of C levels

Conclusions. This study showed that vestibular evoked myogenic potentials (VEMPs) evoked by cochlear implant (CI), could be related to the comfortable level (C level), particularly in the channels that are closer to the apical turn of the cochlea. Objective. The purpose of this study was to investigate the correlation between VEMPs and C level of each channel. Subjects and methods. We investigated 24 children who underwent cochlear implantation. VEMPs were recorded from the operated ears with the CI switched ‘off’ or ‘on’. To investigate the correlation between VEMPs and C level, we selected 13 patients with Nucleus 24 (SPrint), and divided them into group A (normal VEMPs) and B (absence of VEMPs). In these children, all the 22 electrodes were active, and were mapped in the same frequency range for each channel. Results. Twenty children (83%) showed no VEMPs with the CI ‘off’. Among them, 10 elicited VEMPs with the CI ‘on’, but the other 10 did not. In all channels, the mean C levels of CI were higher in group A than in group B. The p values in channels 1–12 were >0.10, in channels 13–16 were 0.06–0.09, and in channels 17–22 were 0.05–0.06, which were lower but not statistically significant.

Vestibular Evoked Myogenic Potentials in Newborns

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 also underwent VEMP test using the same method. Based on adult criteria, 40 newborn ears revealed normal VEMPs in 40%, prolonged VEMPs in 35%, and absent VEMPs in 25%, indicating that great variation exists in the maturation of the sacculocollic reflex at birth. Comparison of VEMP characteristics between healthy newborns and adults revealed nonsignificant difference in the response rate and the latency of n23. However, significant differences existed in the latency of p13, interpeak p13-n23 interval and p13-n23 amplitude between newborns and adults. In conclusion, VEMPs in newborns can be easily recorded by the head rotation method. Prolonged or absent VEMPs in newborns may reflect incomplete maturity of the sacculocollic reflex pathway, especially the myelination. A further large number of newborns receiving MRI scan for other reasons may undergo VEMP test to verify this hypothesis.

Vestibular Evoked Myogenic Potentials in Acute Acoustic Trauma

Anatomical proximity of the saccule to the stapedial footplate points to the possibility of acoustic trauma associated with saccular dysfunction. Therefore, it was the authors' premise that abnormal vestibular evoked myogenic potential (VEMP) after acute acoustic trauma may be caused by saccular damage from very high intensity noise; consequently, irreversible hearing loss ensued. The aim of this study was to investigate the VEMP responses in those with acute acoustic trauma. A prospective study. University hospital. Twenty patients (29 ears) without previous ear disorders diagnosed as acute acoustic trauma were enrolled in this study. Before treatment, each patient underwent pure tone audiometry and caloric and VEMP tests. Correlations between the hearing outcome and mean hearing level, sources of noise, caloric responses, or VEMP results were investigated. After 3 months of medication, complete recovery was achieved in 4 ears and hearing improvement in 4 ears, whereas hearing in 21 ears (72%) remained unchanged. Eighteen ears presenting normal VEMPs revealed hearing improvement in eight ears (44%) and unchanged hearing in ten ears (56%). However, hearing loss remained unchanged in all 11 ears (100%) with absent or delayed VEMPs, exhibiting a significant relationship between VEMP results and hearing outcome. Thus, VEMP test can predict the hearing outcome after acute acoustic trauma with a sensitivity of 44% and a specificity of 100%. The greater the noise intensity, the severer damage on the cochlea and saccule is shown. Absent or delayed VEMPs in ears after acute acoustic trauma may indicate poor prognosis with respect to hearing improvement, whereas normal VEMP is not a powerful indicator for expectation of hearing improvement.

The application of vestibular-evoked myogenic potentials in otoneurosurgery

To evaluate the applicability of vestibular-evoked myogenic potentials (VEMPs) in the diagnostics, intraoperative monitoring, and postoperative follow-up of patients in otoneurosurgery. A prospective study of patients who underwent either cochlear implantation (CI, n = 18) or were diagnosed with an acoustic neuroma (AN, n = 9) or with neuro(micro)vascular compression of the VIIIth nerve (NVC, n = 27) in the period 2002 to 2004. The follow-up was 1 year for all patients. A tertiary-referral unit. VEMPs could be recorded in 64% of all patients before CI and in 22% after surgery. The patients with AN had normal VEMPs in 22% of all cases when first diagnosed. Normal VEMPs were found in 37% of those patients with NVC. From the 5 AN patients who had to be operated, only 1 had intact VEMPs after surgery. In contrast, after microvascular decompression all patients (4) had normal VEMPs. VEMPs are helpful in diagnosing patients with vertigo to better identify saccular defects. They are highly sensitive in the early diagnosis of retrocochlear lesions. VEMPs can help to reliably identify patients with a retrocochlerar lesion at an early stage and can be used in intraoperative, neurophysiological monitoring. C-4.

Differentiating the cause of acute sensorineural hearing loss between Ménière's disease and sudden deafness

Conclusions. Most patients with Ménière's disease (MD) reveal abnormal vestibular-evoked myogenic potentials (VEMPs) and the recruitment phenomenon, whereas most sudden deafness patients display normal VEMPs without the recruitment phenomenon. We therefore recommend using both the recruitment phenomenon and VEMP testing as a diagnostic algorithm to differentiate between MD and sudden deafness as the cause of acute hearing loss. Objective. To recommend a diagnostic algorithm to differentiate between MD and sudden deafness as the cause of acute hearing loss. Material and methods. Between January 2002 and December 2003, 14 consecutive patients with “probable” MD who also had acute sensorineural hearing loss were enrolled in the study, together with another 14 age- and sex-matched patients with idiopathic sudden deafness. Each patient underwent a battery of audiovestibular function tests, including pure-tone audiometry, a stapedial reflex test, distortion-product otoacoustic emissions (DPOAEs), electronystagmography and a VEMP test. All patients were followed for at least 12 months after presentation. Results. Significant differences were found between MD and sudden deafness in terms of the recruitment phenomenon (86% and 21% of cases, respectively) and abnormal VEMP responses (71% and 21% of cases, respectively). However, the diseases did not differ significantly in terms of abnormal DPOAEs or caloric test results.

Vestibular-evoked myogenic potentials in cochlear implant children

Conclusions. Our results suggest that the sacculi of most children with cochlear implants can easily be damaged, as shown by the absence of vestibular-evoked myogenic potentials (VEMPs) in response to click stimuli. Also, in most of the children, the vestibular nerve was seemingly not stimulated by the cochlear implant. These results suggest that electrical stimulation at the C level can stimulate the cochlear nerve; however, this stimulation did not spread to the vestibular nerve in our children. In some children with Mondini dysplasia or vestibulocochlear nerve abnormality, the vestibular nerve was stimulated when the cochlear implant device was on, because of a VEMP response to electrical stimulation. Objective. To clarify the diagnostic value of VEMPs in cochlear implant patients. Material and methods. The click-evoked myogenic potentials of 12 children who underwent cochlear implantation surgery were investigated. The latency and amplitude of the VEMP responses were measured. Results. Before surgery, 6 of the 12 children showed normal VEMPs, 1 showed a decrease in the amplitude of VEMPs and five showed no VEMP response. After surgery, with the cochlear implant device off, 1 child showed a decreased VEMP and 11 showed no VEMPs. With the cochlear implant device on, four children showed VEMPs and eight did not.

Changes in Vestibular Evoked Myogenic Potentials after Meniere Attacks

The aim of this study was to apply videonystagmography (VNG) and vestibular evoked myogenic potential (VEMP) tests to patients with Meniere attacks, to explore the mechanics of where saccular disorders may affect the semicircular canals. From January 2001 to December 2003, 12 consecutive patients with unilateral definite Meniere's disease with vertiginous attacks underwent VNG for recording spontaneous nystagmus, as well as VEMP tests. At the very beginning of the Meniere attack, the spontaneous nystagmus beat toward the lesion side in 5 patients (42%) and toward the healthy side in 7 patients (58%). Twenty-four hours later, only 6 patients (50%) showed spontaneous nystagmus beating toward the healthy side. Nevertheless, spontaneous nystagmus subsided in all patients within 48 hours. The VEMP test was performed within 24 hours of a Meniere attack; the VEMPs were normal in 4 patients and abnormal in 8 patients (67%). After 48 hours, 4 patients with initially abnormal VEMPs had resolution and return to normal VEMPs, and the other 4 patients still had absent VEMPs. Most patients (67%) with Meniere attacks revealed abnormal VEMPs, indicating that the saccule participates in a Meniere attack. This is an important idea that stimulates consideration of the mechanism of Meniere attacks.

Vestibular evoked myogenic potentials induced by intraoperative electrical stimulation of the human inferior vestibular nerve

Vestibular evoked myogenic potentials (VEMPs) can be recorded from sternocleidomastoid muscle (SCM) in clinical practice. The aim of the present study was to investigate VEMPs upon direct electrical stimulation of the human inferior vestibular nerve to evidence the vestibulocollic reflex arch and their saccular origin, respectively. Seven subjects were stimulated at the inferior (IVN) and superior (SVN) vestibular nerve. The EMG signals of the SCM were recorded. These recordings were compared to air- and bone-conduction evoked VEMPs with respect to latency and shape. All subjects showed normal VEMPs upon acoustic stimulation with a latency of 12.8 ± 1.4 ms for P13, and 22.7 ± 2.0 ms for the N23 pre-operatively. Upon direct electrical stimulation of the IVN, the mean latency of the positive peak was 9.1 ± 2.2 and 13.2 ± 2.3 ms for the negative one. No contralateral SCM response was found. Electrical stimulation of the SVN did not result in any EMG response of the SCM. The study shows experimental evidence of the vestibulocollic reflex by direct electrical stimulation of the human IVN for the first time. The method can be utilized to map VIIIth nerve subdivisions and to intraoperatively monitor IVN integrity in a real-time mode.

Vestibular Evoked Myogenic Potentials in Acute Low‐Tone Sensorineural Hearing Loss

It was the authors' premise that the vestibular evoked myogenic potential (VEMP) test may be used to differentiate acute low-tone hearing loss (ALHL) from Meniere's disease with low-tone HL. Prospective study. From January 2000 to December 2002, consecutive 12 patients with ALHL and another 12 patients with definite Meniere's disease with low-tone HL were enrolled in this study. All patients underwent audiometry and VEMP test, before and after treatment with isosorbide for 3 consecutive months. Before treatment, 12 patients with ALHL revealed normal VEMPs (11, 92%) and augmented VEMPs (1). After treatment, 11 (92%) patients had resolved to normal hearing within 3 days. One year later, two (17%) patients progressed to Meniere's disease. In comparison with Meniere's disease, 6 (50%) of 12 patients showed normal VEMPs before treatment, and 7 (58%) patients had their hearing improved 3 months after treatment. Comparison of VEMP responses or hearing outcome between both groups exhibited significant differences. Most patients with ALHL reveal normal VEMPs throughout the episode, indicating that the saccule is spared. In contrast, 50% of Meniere's disease patients with low-tone HL demonstrate abnormal VEMPs, showing a significant difference. Therefore, the VEMP test can be used to differentiate ALHL from Meniere's disease with low-tone HL.

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

Purpose Excluding 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. Methods and materials Fourteen irradiated nasopharyngeal carcinoma (NPC) patients with ROM (18 ears) and 14 age-matched, and gender-matched patients with COM (18 ears) were enrolled. Each patient underwent stimulation with a short tone burst initially, and then by tapping the forehead using a tendon hammer. To define the effect of the neck soft tissue on the VEMP response further, an additional two groups (10 non–NPC patients with ROM but no neck fibrosis/edema and 10 non–NPC patients without ROM but with neck fibrosis/edema) were included for comparison. Results The occurrence of normal VEMPs in the ROM ears (33%) did not differ significantly from that in the COM ears (56%) by tone-burst stimulation. However, using tapping evocation, most (89%) COM ears revealed normal VEMPs, and most (61%) ROM ears demonstrated delayed VEMPs. Furthermore, most (90%) non–NPC patients with ROM but no neck fibrosis/edema revealed delayed or absent VEMPs. In contrast, all non–NPC patients with neck fibrosis/edema but no ROM demonstrated normal VEMPs bilaterally, implying that the effect of neck soft tissue on the VEMP response is less. Conclusion Through tapping evocation, most COM ears revealed normal VEMPs, and most ROM ears demonstrated delayed VEMPs, indicating that ROM is different from COM because of the larger affected areas such as retrolabyrinthine or brainstem involvement. This result can explain why grommet insertion or tympanoplasty is not beneficial to postirradiated ears, possibly because both operations spare the inflammation outside the middle ear cavity.

Vestibular evoked myogenic potentials in response to skull taps for patients with vestibular neuritis

In recent years it has been demonstrated that loud clicks generate short latency vestibular evoked myogenic potentials (VEMP). It has also been demonstrated that skull tap stimulation evokes similar VEMP. In the present study, the differences between the click-induced and the skull-tap induced VEMP were studied in 18 patients at onset of vestibular neuritis. Gentle skull taps were delivered manually above each ear on the side of the skull and on the forehead midline. The muscular responses were recorded over both sternocleidomastoid muscles using skin electrodes. Abnormal skull tap VEMP were found in the majority of the patients (10/18, 56%). However, only 4/18 (22%) showed asymmetry in the click-induced VEMP. The high percentage of abnormal skull tap VEMP might suggest that this response is not only dependent on the inferior division of the vestibular nerve, because the inferior division of this nerve is usually spared in vestibular neuritis. Moreover, the patients with abnormal skull tap VEMP differed from those with normal VEMP in their settings of the subjective visual horizontal with static head tilt in the roll plane. This might suggest that skull tap VEMP are (also) related to utricular function.