Variance of vestibular-evoked myogenic potentials

OBJECTIVES/HYPOTHESIS: Vestibular-evoked myogenic potential (VEMP) has been thought to originate from sacculus. The variance of this potential and the effectiveness of the adjustments of pInII amplitudes using average muscle tonus of ipsilateral sternocleidomastoid muscle were evaluated. In addition, clinical application of VEMP was examined in patients with acoustic tumors (ATs) and vestibular neurolabyrinthitis (VNL). STUDY DESIGN: Prospective evaluation of the VEMP in 18 normal volunteers and 6 patients. METHODS: Variance and left-right difference of each parameter, including pI latency, nII latency, pInII amplitude, and threshold, was analyzed. Input-output function of pInII amplitude was evaluated. Average muscle tonus was calculated in 20 ears and applied for adjustment of pInII amplitude. Sensitivity of each parameter of VEMP was examined in 3 patients with ATs and 3 patients with VNL. RESULTS: VEMP was present in all 36 ears of 18 control subjects. Thresholds of VEMP for normal subjects were 80 to 95 dB normal hearing level (nHL). The muscle tonus affected pInII amplitude significantly; however, no statistically significant improvement was observed in test-retest investigation after adjustment using muscle tonus. The threshold of the affected side was elevated compared with the non-affected side in all patients with ATs, whereas 2 of 3 patients showed normal pInII-ratio. One patient with VNL presented normal VEMP, whereas 2 patients presented no VEMP to the highest stimulus intensity. CONCLUSIONS: Interaural difference of thresholds might be the most useful parameters. Adjustment using average muscle tonus is not necessary when the subject is able to get sufficient muscle tonus.     

Effect of click duration on vestibular-evoked myogenic potentials

CONCLUSIONS: The 0.5-VEMP demonstrated a more prominent waveform morphology than either the 0.1- or 0.2-VEMPs. In addition, the 0.5-VEMP had smaller interaural latency differences than the 1.0-VEMP. These findings suggest that 0.5 ms is superior to other click durations in terms of yielding VEMP responses for clinical use. OBJECTIVE: In order to establish the ideal stimulus condition for vestibular-evoked myogenic potentials (VEMPs), we studied the use of various click durations to generate different response patterns in normal subjects. The influence of click durations on VEMPs is described and the optimal stimulation duration for clinical use is suggested. MATERIAL AND METHODS: This was a prospective study. Eighteen healthy volunteers (36 ears) underwent VEMP tests. Four click durations (0.1, 0.2, 0.5 and 1.0 ms) were used in a random order to elicit VEMP responses (0.1-, 0.2-, 0.5- and 1.0-VEMP, respectively). The latency of each peak (p13, n23), the peak-to-peak interval and amplitude (p 13-n23) and the relative amplitude (defined as the amplitude divided by that of the 0.5-VEMP) were measured and compared. RESULTS: Click stimulation of 34 ears (94%) produced 0.1-VEMP responses, whereas positive 0.2-, 0.5- and 1.0-VEMP responses were observed in 36 (100%). The latencies of peaks p13 and n23 were significantly prolonged between successive stimulus durations from 0.1 to 1.0 ms (p <0.05), in contrast to the p13-n23 intervals (p >0.05). The 1.0-VEMP displayed the largest SDs of latencies and interval among the four different VEMPs. The relative amplitude was significantly increased between successive durations from 0.1 to 0.5 ms (alphaT <0.05), but there was no significant difference between 0.5 and 1.0 ms (alphaT >0.05).     

Postoperative vestibular-evoked myogenic potentials in cases with vestibular schwannomas

Although still the subject of discussion, vestibular-evoked myogenic potentials (VEMPs) have been considered to reflect the function of the saccular and, more recently, the cochlear tracts. To accurately determine the precise afferent pathway carrying VEMPs, we studied the outcomes of VEMPs and other examinations in patients with unilateral vestibular schwannomas. Eleven patients with unilateral vestibular schwannomas resected using a middle cranial fossa approach were included in the study. Patients underwent pure-tone threshold audiometry, caloric tests and analysis of auditory brainstem responses (ABRs) and VEMPs pre- and postoperatively. The results were compared with those obtained in patients with intact superior or inferior vestibular and cochlear nerves. Among the 11 patients studied, 4 retained their VEMPs postoperatively. Three of the 10 patients with inferior vestibular schwannomas exhibited normal VEMPs, preserved hearing levels (20 dB HL) and anatomically intact superior vestibular nerves. In all of these cases, ABRs more closely correlated with VEMPs than with caloric responses. In one of the cases with inferior vestibular schwannomas, VEMPs were preserved postoperatively and VEMP latencies were shortened, which indicates the preoperative presence of a conduction block in either the cochlear or superior vestibular nerve. VEMPs may be conducted in both the superior vestibular and cochlear nerves, as well as in the inferior vestibular nerve. Thus, evaluation of saccular nerve function should be performed carefully, especially in cases where hearing is preserved. It appears that cochlear conduction may proceed along two pathways, one direct and the other via the brainstem, but this remains to be verified.     

Pathological eye movements influence on the recordings of ocular vestibular-evoked myogenic potential

Objective: This study investigated the influence of pathological eye movements on the recordings of ocular vestibulo-evoked myogenic potential (oVEMP).

Methods: Ten patients with pathological eye movements of non-vestibular origin (nine congenital nystagmus and one opsoclonus) who had negative MRI result were assigned to Group A. Another 20 vestibular neuritis (VN) patients with spontaneous nystagmus were assigned to Group B. Both groups underwent audiometry, and caloric, oVEMP and cervical VEMP (cVEMP) tests.

Results: In Group A, the caloric, oVEMP and cVEMP tests showed 40%, 55% and 50% abnormalities, respectively. In Group B (VN), caloric, oVEMP and cVEMP tests revealed 100%, 80% and 45% abnormalities on the lesion ears, and 0%, 40% and 0% abnormalities on the healthy (opposite) ears, respectively. The 40% oVEMP abnormality on the healthy ears may be due to recording failure from the presence of spontaneous nystagmus, since five of five VN patients showed normal oVEMPs on the healthy ears, one year after presentation.

Conclusions: Presence of pathological eye movements may affect the recordings of oVEMP. Thus, the oVEMP test is recommended to perform after acute vertiginous episode to exclude the influence of pathological eye movements on the oVEMP recordings.     

The influence of unilateral versus bilateral clicks on the vestibular-evoked myogenic potentials.

OBJECTIVE: Because a continuous muscular effort is required during recording of vestibular-evoked myogenic potentials, we assume vestibular-evoked myogenic potentials elicited by simultaneous bilateral clicks can be used as a more convenient mode compared with respective unilateral clicks. To investigate whether bilateral clicks provide the same information as unilateral clicks, we examined whether the responses are different between them in normal subjects and whether bilateral clicks have the same diagnostic value as vestibular-evoked myogenic potentials elicited by unilateral clicks in detecting retrolabyrinthine lesions. STUDY DESIGN: Prospective study. SETTING: Academic tertiary referral center. SUBJECTS: Fourteen healthy volunteers and four patients with unilateral cerebellopontine angle tumors were enrolled in this study. INTERVENTIONS: Recordings of vestibular-evoked myogenic potential responses. MAIN OUTCOME MEASURES: The latency of each peak (p13, n23), the peak-to-peak interval, and amplitude (p13-n23). RESULTS: Both unilateral and bilateral click stimulation of 28 ears (100%) produced vestibular-evoked myogenic potentials in normal subjects. The mean latencies of p13 and n23, peak-to-peak interval, and amplitude of vestibular-evoked myogenic potentials elicited with unilateral clicks were 11.62 +/- 0.99 ms, 19.74 +/- 1.30 ms, 8.12 +/- 1.66 ms, and 110.79 +/- 61.37 microV, respectively, whereas those elicited with bilateral clicks were 11.16 +/- 0.51 ms, 19.22 +/- 1.61 ms, 8.06 +/- 1.66 ms, and 111.77 +/- 40.98 microV, respectively. There was a significant difference (p < 0.05) in the latencies, but not for the interval and amplitude (p > 0.05). Four patients with unilateral cerebellopontine angle tumors and prolonged latencies of unilateral clicks vestibular-evoked myogenic potentials also showed latency prolongation in bilateral clicks vestibular-evoked myogenic potentials. CONCLUSION: Although the use of bilateral acoustic stimulation shortens the vestibular-evoked myogenic potential latencies in normal subjects, it does not affect the bilateral clicks vestibular-evoked myogenic potential ability to detect retrolabyrinthine lesions. Bilateral clicks vestibular-evoked myogenic potentials are a more convenient mode with which to help diagnose both labyrinthine and retrolabyrinthine lesions than unilateral clicks vestibular-evoked myogenic potentials.     

Preoperative versus postoperative role of vestibular-evoked myogenic potentials in cerebellopontine angle tumor

OBJECTIVE/HYPOTHESIS: Vestibular-evoked myogenic potential (VEMP) examination was performed on patients with a cerebellopontine angle (CPA) tumor to evaluate its clinical role. METHODS: Patients with a CPA tumor were subjected to caloric test and VEMP examination. Follow-up study was performed 1 year after the surgery. RESULTS: Six (69%) of the 9 tumors did not exhibit either caloric response or VEMP on the lesioned side. Three patients received tumor excision and all tumors involved both the superior and inferior vestibular nerves. Two (22%) of the 9 tumors had normal caloric responses but no VEMP. One underwent surgical excision, and the tumor originated from the inferior vestibular nerve. In the follow-up study, only 1 patient with epidermoid cyst presented complete recovery of caloric response and VEMP, whereas in the other 3 patients with vestibular schwannoma, the responses were all absent persistently. CONCLUSION: Before surgery, VEMP test can be used to predict the nerve of origin and to formulate the best surgical approach. After surgery, VEMP test can be used to define the nature of the tumor (compressing or infiltrating the nerve) and disclose the residual function of the inferior vestibular nerve.     

A study on vestibular-evoked myogenic potentials via galvanic vestibular stimulation in normal people

Objectives

The aim of our study is to examine vestibular-evoked myogenic potentials (VEMPs) elicited by the galvanic vestibular stimulation in the sternocleidomastoid muscle (SCM) in healthy subjects for clinical applications of auditory neuropathy or vestibular neuropathy in the future.

Vestibular-evoked myogenic potentials in patients with otosclerosis using air- and bone-conducted tone-burst stimulation.

OBJECTIVE: Otosclerosis is a progressive disease with a remodeling process causing ossicular malformation and conductive hearing loss. The aim of this study was to investigate whether vestibular-evoked myogenic potential (VEMP) correlates with the progression of otosclerosis. DESIGN: Fifteen patients with otosclerosis (21 ears) without operation and 10 healthy subjects (20 ears) underwent VEMP test using air-conducted (AC) and bone-conducted (BC) tone-burst stimulation. SETTING: Tertiary referral university hospital. RESULTS: In 21 unoperated otosclerotic ears, 5 ears (24%) showed present AC-VEMPs, and 16 ears had absent AC-VEMPs. Conversely, 16 ears (76%) displayed present BC-VEMPs and 5 ears with absent BC-VEMPs. In those with both AC- and BC-VEMPs, none of them showed air-bone gap greater than 30 dB; in those with absent AC-VEMPs but present BC-VEMPs, 27% of the ears had air-bone gap greater than 30 dB; and in those with absence of both AC- and BC-VEMPs, 80% of the ears revealed air-bone gap greater than 30 dB. Thus, a significant relationship existed among the presence of AC-VEMPs, BC-VEMPs, and magnitude of conductive hearing loss. CONCLUSION: The presence of an AC-VEMP may indicate an earlier stage of otosclerosis, although absent BC-VEMP infers a later stage. Restated, AC-VEMPs may complement the results obtained with BC-VEMPs to classify the stage of otosclerosis.     

Eliciting constant and prominent waves n34-p44 of vestibular-evoked myogenic potentials

OBJECTIVE: The serial peaks of vestibular-evoked myogenic potentials (VEMPs) have been labeled p13, n23, n34 and p44 according to their latency. Waves p13-n23 have been shown to be of saccular origin, whereas the origin of waves n34-p44 is still unknown. In order to improve the clinical applicability of waves n34-p44, we examine the use of different patterns of acoustic stimuli to evoke constant and prominent VEMPs, especially waves n34-p44. MATERIAL AND METHODS: In this prospective study 27 healthy volunteers (54 ears) underwent VEMP tests. Three kinds of click intensity (85, 95 and 105 dB nHL) were presented in a random order to evoke 85-VEMP, 95-VEMP and 105-VEMP, respectively. The response rate, latency of each peak, peak-to-peak interval and amplitude of waves p13-n23 and n34-p44 were measured and analyzed. RESULTS: The response rates of waves p13-n23 in 85-VEMP, 95-VEMP and 105-VEMP were 26% (14/54), 89% (48/54) and 98% (53/54), respectively. Significant differences in the response rate existed between 85-VEMP and both 95-VEMP and 105-VEMP (p<0.01), whereas there was a non-significant difference between 95-VEMP and 105-VEMP (p>0.05). In contrast, the response rates for eliciting waves n34-p44 were 19% (10/54), 63% (34/54) and 89% (48/54), using 85, 95 and 105 dB acoustic stimuli, respectively. A significantly higher response rate for waves n34-p44 occurred when the intensity of the stimuli increased (p<0.01). Although neither latencies nor interval exhibited a significant difference between 95-VEMP and 105-VEMP, the amplitude of 105-VEMP was significantly greater than that of 95-VEMP for both waves p13-n23 and n34-p44. CONCLUSION: An acoustic stimulus intensity of 105 dB nHL is required to reliably elicit waves n34-p44 in subjects with normal hearing.     

The effects of plateau time on vestibular-evoked myogenic potentials triggered by tone bursts

Vestibular-evoked myogenic potentials (VEMPs) can be triggered by acoustic, vibratory or galvanic stimuli. However, each method has drawbacks for studying if the vestibulocollic reflex is intact in the patients tested. We used air-conducted VEMPs as a screening test to examine the integrity of the sacculocollic reflex. In a previous study, we defined the optimal rise/fall time of short tone bursts (STBs) to evoke VEMPs. In this paper, we studied the optimal plateau time of tone bursts to evoke VEMPs. Four different plateau times (1, 2, 5 and 10 ms) were used in a random order to test 26 normal ears. VEMP responses (p13/n23) triggered by the tone bursts were clearly observed in all ears. When the plateau time was increased in order from 1 to 10 ms, the latencies (p13, n23) and interval (p13-n23) were also increased in parallel, although significant differences were not observed between some plateau times. Considering the latencies and interval together for the four plateau times, the variances were smallest for the 2 ms plateau time, meaning that it caused the smallest interaural VEMP differences. The amplitude or relative amplitude in individual ears was lowest for the 1 ms plateau time, while it was comparable for the other three plateau times. In conclusion, we recommend that the ideal stimulation pattern for evoking STB VEMPs is as follows: frequency 500 Hz; stimulation repetition rate 5 Hz; rise, fall time 1 ms; and plateau time 2 ms. The waveform morphology of the VEMP responses observed with this stimulation pattern was simultaneously the most constant and marked.     

Short tone bursts are better than clicks for cervical vestibular-evoked myogenic potentials in clinical practice

Our aim is to compare short tone burst (STB)—and clicks—stimuli to evoke vestibular-evoked myogenic potentials (VEMPs) in healthy controls. A cross-sectional study in which VEMPs were measured in two sets of 185 and 55 normal volunteers by an air-conducted 500?Hz STBs and clicks, respectively. The test–retest reliability between different sessions was assessed in two subsets of 35 individuals. Moreover, 53 individuals were examined with both stimuli within the same session. Intraclass correlation coefficients (ICC) were used to assess reliability for P1 and N1 latencies, corrected amplitude and asymmetry ratio (AR). The results included that STBs produced a reliable response between different sessions (N?=?35; [ICC]?=?0.61–0.94, all p?<?0.0001). Although clicks produced a reliable response for P1 and N1 latencies and corrected amplitudes (ICC?=?0.62–0.74, all p?<?0.0001), the amplitude ratio showed a lower reliability [ICC?=?0.32 (?0.10 to 0.59)]. The amplitude of VEMP was consistently larger with 500?Hz STBs than clicks for a given sound pressure level. Within the same session, STBs evoked a response in 52/53 subjects (98%) whereas clicks evoked VEMPs only in 44/53 individuals (83%). Conclusions revealed that a 500?Hz STBs elicited consistently larger amplitudes, better reliability across recording sessions and fewer missing responses compared with click-induced VEMPs.     

健康飞行员与飞行学员气导声诱发的在眼外肌上记录的前庭诱发肌源性电位

目的记录中国空军战斗机飞行(学)员气导声诱发的oVEMP(ocular vestibular-evoked myogenic poten-tial,眼外肌上诱发的前庭肌源性电位)的特征性参数,以便建立战斗机飞行(学)员的正常值数据。方法 62名健康飞行学员(30名男性和32名年龄匹配的女性)和31名现役健康战斗机飞行员作为受试者,采用气导短纯音(short tone burst,STB)双侧给声双侧进行记录。记录93名健康飞行(学)员STB-oVEMP的nI和pI潜伏期、nI-pI间期、nI-pI的波间幅度以及双侧幅度不对称比,以获得正常值数据。对年龄与性别对oVEMP的影响也进行了观察。结果 93名健康飞行(学)员oVEMP的nI和pI潜伏期、nI-pI间期、nI-pI的波间幅度以及双侧幅度不对称比分别为(10.35±0.66)ms,(15.18±1.07)ms,(4.75±0.99)ms,(6.75±4.13)μV,以及(13.22±9.13)%。男性飞行学员与男性现役战斗机飞行员间在oVEMP的各个特征性参数上无显著差别。年龄匹配的男女性飞行学员仅在nI-pI的波间幅度上存在显著差别,分别为男性(6.96±3.85)μV和女性(5.47±3.10)μV。结论在oVEMP幅度上存在性别差异,年龄对oVEMP参数似乎没有影响。因此应该采用双侧幅度不对称比而不能仅仅采用绝对幅度参数来评估oVEMP的检测结果。飞行(学)员需要按照性别分别建立oVEMP的正常值范围。     

气导声刺激前庭诱发肌源性电位在正常儿童中的表现

目的 探讨研究正常儿童中气导声刺激诱发的眼性前庭诱发肌源性电位(oVEMP)和颈性前庭肌源性诱发电位(cVEMP)的各项参数指标,并对正常值进行统计学处理分析。 方法 选择4~10岁听力正常健康儿童52例,以500 Hz短纯音作为刺激音,分别行 oVEMP和cVEMP检测,记录左、右耳引出率及波形参数,并采用SPSS统计软件进行统计学处理分析。 结果 双耳皆未引出oVEMP 2例,单耳可引出oVEMP4例,oVEMP总体引出率为92%。双耳皆未引出cVEMP 2例,cVEMP总体引出率为96%。oVEMP与cVEMP的P1潜伏期分别为(17.07±0.89)ms、(15.55±1.58)ms;N1潜伏期分别为(12.39±0.91)ms、(23.10±2.29)ms;N1P1间期分别为(4.68±0.88)ms、(7.83±1.56)ms;oVEMP与cVEMP的振幅分别为(7.24±4.79)μV、(197.40±118.37)μV。双耳间oVEMP及cVEMP振幅不对称比分别为(19.03±12.50)%、(22.16±18.64)%。患儿左右耳的潜伏期,P1N1间期及振幅差异无统计学意义(P>0.05)。 结论 绝大部分正常儿童经气导声刺激可引出oVEMP与cVEMP。该检测患儿依从性高,可用来评估儿童前庭功能。此研究结果可为我国的儿童气导VEMP提供正常参考值范围。     

Vestibular function in panic disorder patients: a vestibular-evoked myogenic potentials and video head impulse test study

European Archives of Oto-Rhino-Laryngology - To evaluate the function of the utriculus and sacculus and their central connections by ocular and cervical vestibular-evoked myogenic potentials...     

Comparison of furosemide-loading cervical vestibular-evoked myogenic potentials with magnetic resonance imaging for the evaluation of endolymphatic hydrops

Abstract

Background

Furosemide-loading cervical vestibular-evoked myogenic potential (FVEMP), in which vestibular function is improved via diuretics-induced dehydration, can be used to estimate the presence of endolymphatic hydrops, one characteristic of Menière’s disease. Inner ear magnetic resonance imaging (MRI) can also reveal endolymphatic hydrops.

Aims/Objective: This study aimed to compare and confirm the usefulness of these two examination methods for the diagnosis of Menière’s disease.     

Acoustic tensor tympani response and vestibular-evoked myogenic potential

OBJECTIVE: To investigate the acoustic response properties and the vestibular-evoked myogenic potential (VEMP) in various lesions. STUDY DESIGN: Retrospective study of the clinical records of patients. METHODS: Neurotological tests including acoustic response and VEMP were performed and analyzed in 62 patients with facial palsy, otosclerosis, ossicular chain interruption, sensorineural hearing loss, or acoustic tumor. RESULTS: Inverted acoustic responses were observed in 25 of 38 (65.8%) patients with facial palsy, in 5 of 6 (83.3%) patients with acoustic tumor, and in all patients with otosclerosis, ossicular chain interruption, or sensorineural hearing loss. These inverted responses were obtained only when ipsilateral stimulation was used. The thresholds of the inverted responses were statistically significantly higher than those of the normal response. CONCLUSIONS: The vibration of the eardrum is thought to stimulate the ipsilateral trigeminal nerve, leading to contraction of the tensor tympani muscle. The stapedius response had an inhibitory effect on the inverted response. Vibration of the stapes footplate (which requires a normal middle ear conduction system) is necessary to induce the VEMP, whereas the functioning of the facial and cochlear nerves is independent of the VEMP response.     

Testing vestibular-evoked myogenic potentials with 90-dB clicks is effective in the diagnosis of superior canal dehiscence syndrome

Vestibular-evoked myogenic potentials (VEMP) in response to 90-dB-nHL clicks were studied in 20 patients (22 ears) with superior canal dehiscence syndrome. Their amplitude was compared to the VEMP from the 'unaffected' ears of 113 patients using the same stimulus level. The 113 control subjects were those from a previous study on 1,000 patients who had had large VEMP amplitudes in response to 500-Hz 129-dB-SPL tone bursts, and, because of this, had been tested with 90-dB-nHL clicks (which are a much weaker sound stimulus than our routine 500-Hz tone burst). It was found that 90-dB-nHL clicks clearly distinguished patients with vestibular hypersensitivity to sounds. In patients, the VEMP amplitude was usually larger than the simultaneously recorded background electromyographic activity (i.e. 'corrected' amplitude >1), whereas this was not the case for the controls. Consequently, it is suggested that 90-dB-nHL clicks can be used to screen for vestibular hypersensitivity to sounds. This finding has clinical implications for patients with suspected Tullio phenomenon because the definitive VEMP test for this (i.e. estimation of VEMP threshold) is not only time-consuming, but there is also difficulty related to the low signal-to-noise ratio close to the threshold.     

Preliminary study on vestibular-evoked myogenic potential induced by bone-conducted stimuli.

OBJECTIVE: To study the relationship between vestibular-evoked myogenic potential evoked by air-conducted stimuli (A-VEMP) and those evoked by bone-conducted stimuli (B-VEMP). STUDY DESIGN: Prospective study. SETTING: University Hospital. PATIENTS: To determine the optimum stimulus conditions for B-VEMP, 40 ears of 20 healthy volunteers were used. To compare results of A-VEMP and B-VEMP, 60 ears of 30 healthy volunteers and 70 ears of 35 patients with unilateral vestibular disorder without conductive hearing loss were used. MAIN OUTCOME MEASURE: A-VEMP and B-VEMP were measured. Both examinations involved evaluation of the interaural ratio (IAR) of the p13-n23 peak-to-peak amplitude. To compare the relationship between A-VEMP and B-VEMP in healthy subjects and patients with unilateral vestibular disorder. RESULTS: The optimum stimulus for B-VEMP seemed to be a tone-burst sound with 8-ms duration at 250 Hz. In all healthy subjects, both A-VEMP and B-VEMP could be recorded. The mean IAR of B-VEMP (0.5 +/- 21.0%) was not significantly different from that of A-VEMP (0.2 +/- 19.4%). In patients with unilateral vestibular disorder, B-VEMP could not be detected in 10 ears in which A-VEMP also could not be detected. The IAR of A-VEMP was strongly correlated with that of B-VEMP (correlation coefficient, 0.98). CONCLUSION: The results of B-VEMP were almost the same as those for A-VEMP, at least, for patients without conductive hearing loss.