Normative Data of Ocular Vestibular Evoked Myogenic Potentials in Response to Chirp Stimulus

Masseter Vestibular evoked myogenic potentials: A new tool to assess the vestibulomasseteric reflex pathway

Purpose

This review article provides the readers with an in-depth insight in understanding and interpreting various research literatures on the masseter vestibular evoked myogenic potentials (mVEMP). The article also reviews the contemporary researches involving the clinical applications of the mVEMP.

Conclusions

Masseter VEMP is an evolving yet clinically promising neuro-otology test tool that has recently gained more research interest and is considered an additional tool to diagnose various vestibular disorders. Masseter VEMP assesses the functional integrity of the acoustic-masseteric and vestibulo-masseteric reflex pathways. The mVEMP could be used as a complementary test to evaluate the same peripheral generator as the cervical VEMP but a different central pathway i.e., vestibulo-trigeminal pathway. Various research studies that have experimented on parameters such as the effect of different electrode montages (zygomatic vs mandibular configurations), stimulation rates, filter settings and stimuli used to evoke mVEMP have been discussed in this article that could assist in the optimization of a comprehensive clinical protocol. The latency and the amplitude of mVEMP waveforms serve as significant parameters in differentiating normals from those of the clinical populations. Along with the cVEMPs and oVEMPs, mVEMP might help diagnose brainstem lesions in REM Sleep behaviour disorders, Multiple Sclerosis and Parkinson's disease. However, further studies are required to probe in this area of research.

Influence of the Electrode Montage to Detect Ocular Vestibular Evoked Myogenic Potentials

OBJECTIVE

To compare ocular vestibular evoked myogenic potentials (oVEMPs) obtained with three different electrode montages (infra-orbital vs belly-tendon vs chin) in a group of healthy subjects. To assess the electrical activity recorded at the level of the reference electrode in the belly-tendon and chin montages.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

PATIENTS

Twenty-five healthy adult volunteers.

INTERVENTIONS

Each ear was tested separately via air-conducted sound (500 Hz Narrow Band CE-Chirps at 100 dB nHL) for recording contralateral myogenic responses. Recording conditions were randomized.

MAIN OUTCOME MEASURES

n1-p1 amplitudes values, interaural amplitude asymmetry ratios (ARs) and response rates.

RESULTS

The belly-tendon electrode montage (BTEM) produced larger amplitudes than the chin ( p = 0.008) and the IOEM (infra-orbital electrode montage; p < 0.001). The chin montage displayed larger amplitudes than the IOEM ( p < 0.001). The interaural amplitude asymmetry ratios (ARs) were not affected by the different electrode montages ( p = 0.549). In 100% of cases, oVEMPs were detected bilaterally with the BTEM which is higher than with the chin and the IOEM ( p < 0.001; p = 0.020, respectively). We did not record any VEMP when placing the active electrode on the contralateral internal canthus or the chin and the reference electrode on the dorsum of the hand.

CONCLUSIONS

The BTEM increased the amplitudes recorded and response rate in healthy subjects. No positive or negative reference contamination was observed with the belly-tendon or chin montages.

Comprehensive Normative Data for Objective Vestibular Tests

INTRODUCTION

 Vestibular dysfunction is a debilitating disorder frequently encountered in neurological and otological settings. The vestibular system is a complex network between peripheral and central mechanisms. This innate complexity of the vestibular system necessitates objective test procedures for evidence-based diagnostic formulations and intervention. Objective tests aid in the evaluation of both peripheral and central vestibular pathologies. Establishing and availability of comprehensive normative data for these objective tests is crucial for clinicians and researchers alike.

MATERIALS AND METHODS

This is a prospective study involving 120 participants (both males and females) aged between 18 and 55 years. All participants were right-handed individuals and had no significant medical history. On pre-set protocols, cVEMP (cervical vestibular evoked myogenic potential), oVEMP (ocular vestibular evoked myogenic potential), vHIT (video head impulse test), and VNG (videonystagmography) were done.

RESULTS

While all participants (n=120) underwent cVEMP, oVEMP, vHIT, saccade, smooth pursuit, and optokinetic tests, only 109 participants consented to the caloric test. Each test's mean, standard deviation, median, quartile, and third quartiles have been recorded. A right-left comparison yielded no significant difference on cVEMP, oVEMP, caloric test, smooth pursuit, and optokinetic test. However, few vHIT and saccade parameters did reveal significant differences.

DISCUSSION

This study presents comprehensive normative data for cVEMP, oVEMP, vHIT, caloric test on VNG, and oculomotor tests (smooth pursuit, saccade, optokinetic) on VNG. The test results were in concordance with previously published data. The significant difference between the right and left sides in vHIT may be because of the monocular goggles used for the testing.

CONCLUSION

This study brings out the normative data for various vestibular tests on individuals aged between 18-55 years. This information could aid both clinicians and researchers working in the field of vestibular science.

Comparison of Chirp Versus Tone Burst- and Click-Evoked Masseteric Vestibular Evoked Myogenic Potentials in Normal-Hearing Adults

PURPOSE

This study aimed at comparing narrowband Claus Elberling level-specific chirp (NB CE-Chirp)-, click-, and tone burst-evoked masseteric vestibular evoked myogenic potentials (mVEMPs).

METHOD

Within-group study design and purposive sampling were performed. A total of 25 normal-hearing individuals participated in the study. The zygomatic electrode montage was used to elicit ipsilateral mVEMP responses using a 500-Hz NB CE-Chirp, a click of 100-μs duration, and a 500-Hz tone burst stimulus. Each of the responses was analyzed based on the absolute peak latency of P11 and N21, the electromyography-scaled peak-to-peak amplitude of the P11-N21 complex, and the interaural asymmetry ratio.

RESULTS

A total of 50 ears were tested and had 100% mVEMP responses. The latencies of click-evoked and 500-Hz NB CE-Chirp-evoked mVEMPs were significantly shorter than those of 500-Hz tone burst-evoked mVEMPs (p < .05) for both ears. It revealed a significantly superior P11-N21 amplitude of the 500-Hz NB CE-Chirp and tone burst than clicks for both ears. Intraclass correlation coefficient revealed moderate to excellent test-retest reliability for mVEMP parameters across three different stimulations.

CONCLUSION

The present study supports 500 Hz NB CE-Chirps as effective and reliable stimuli as tone bursts in eliciting mVEMP responses.

Comparison of Compressed High-Intensity Radar Pulse and Tone Burst Stimulation in Vestibular Evoked Myogenic Potentials in Acute Peripheral Vestibular System Pathologies

BACKGROUND

It is ascertained that the compressed high-intensity radar pulse (CHIRP) is an effective stimulus in auditory electrophysiology. This study aims to investigate whether Narrow Band Level Specific Claus Elberling Compressed High-Intensity Radar Pulse (NB LS CE-CHIRP) stimulus is an effective stimulus in the vestibular evoked myogenic potentials test.

METHODS

A case-control study was designed. Fifty-four healthy participants with no vertigo complaints and 50 patients diagnosed with acute peripheral vestibular pathology were enrolled in this study. Cervical and ocular vestibular evoked myogenic potential tests (cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials) with 500 Hz tone burst and 500 Hz Narrow Band Level Specific CE-CHIRP stimulations were performed on all participants. In addition, cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials tests with 1000 Hz tone burst and 1000 Hz Narrow Band Level Specific CE-CHIRP were performed on 24 Meniere's disease patients. P1 latency, N1 latency, amplitude, threshold, and the asymmetry ratio of responses were recorded.

RESULTS

In healthy participants, with CHIRP stimulus, shorter P1 latency (P < .001), shorter N1 latency (P < .001), and lower threshold (P = .003) were obtained in the cervical vestibular evoked myogenic potentials test; shorter P1 latency (P < .001), shorter N1 latency (P < .001), higher amplitude (P < .001), and lower threshold (P < .001) were obtained in ocular vestibular evoked myogenic potentials test. In symptomatic ears of patients, with CHIRP stimulus, shorter P1 latency (P < .001), shorter N1 latency (P < .001), and lower threshold (P=.013 in cervical vestibular evoked myogenic potentials; P=.015 in ocular vestibular evoked myogenic potentials) were obtained in cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials tests. In asymptomatic ears of patients, with CHIRP stimulus, shorter P1 latency (P < .001) and shorter N1 latency (P < .001) were obtained in the cervical vestibular evoked myogenic potentials test; shorter P1 latency (P < .001), shorter N1 latency (P < .001), higher amplitude (P < .001), and lower threshold (P=.006) were obtained in ocular vestibular evoked myogenic potentials test.

CONCLUSION

Our results suggest that due to higher response rates, shorter latencies, higher amplitude, and lower threshold values, the Narrow Band Level Specific CE-CHIRP stimulus is an effective stimulus for both cervical vestibular evoked myogenic potentials and ocular vestibular evoked myogenic potentials tests.

Cervical and ocular vestibular evoked myogenic potential: A comparison of narrowband chirp, broadband chirp, tone burst and click stimulation

OBJECTIVES

To compare the response rate and response parameters of cervical and ocular vestibular evoked myogenic potentials (c&oVEMP) elicited by narrowband (NB) and broadband (BB) CE-Chirp, with the more classical tone burst (TB) and click VEMPs.

DESIGN

The response rate, latency, amplitude and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air conducted (AC) 500 Hz NB CE-chirp, BB CE-chirp, 500 Hz TB and click stimuli were recorded bilaterally.

STUDY SAMPLE

20 male and 38 female participants (19-39 years).

RESULTS

For the cVEMP, the highest response rate was found for NB chirp (100%), followed by TB (91%), BB chirp (87%) and finally click (85%). A similar order was seen for oVEMP with percentages of 100%; 57%, 57%, and 43%. The 500 Hz NB CE-Chirp elicited significantly shorter cVEMP P1 and N1 latencies and significantly larger c&oVEMP amplitudes compared to all other stimuli. BB CE-Chirp elicited significantly shorter c&oVEMP P1 and N1 latencies with smaller amplitudes compared to TB. Asymmetry ratios were not statistically significant for all comparisons.

CONCLUSION

The 500 Hz NB CE-chirp provides the highest response rates, shorter latencies and larger amplitudes, and therefore seem a promising stimulus for reliably measuring c&oVEMPs in clinical practice.

Using Narrow Band CE-Chirps to Elicit Cervical Vestibular Evoked Myogenic Potentials

Objectives:

To compare the effects of Narrow band CE-Chirps (NB CE-Chirps) and tone bursts (TBs) at 500 Hz and 1000 Hz on the amplitudes and latencies in cervical vestibular evoked myogenic potentials (cVEMPs).

Design:

Thirty-one healthy adult volunteers of varying ages were tested by air conduction at 95 dB nHL. Recording conditions were randomized for each participant and each modality was tested twice.

Results:

NB CE-Chirps showed larger corrected amplitudes than TBs at 500 Hz (p < 0.001) which were themselves larger than NB CE-Chirps and TBs at 1000 Hz (p < 0.001). In older volunteers, NB CE-Chirps 500 and 1000 Hz had significantly higher response rates than TBs 500 Hz (p = 0.039). A negative correlation was observed between the corrected amplitudes and the age of the participants regardless of the stimulus and the frequency studied. The p13 and n23 latencies were not correlated with the age of the subjects.

Conclusions:

NB CE-Chirps at 500 Hz improved the corrected amplitudes of waveforms in cVEMPs as a result of a better frequency specificity compared with TBs. In the elderly, eliciting cVEMPs at a frequency of 1000 Hz might not be necessary to improve response rates with NB CE-Chirps. Additional studies including a higher number of healthy participants and patients with vestibular disorders are required to confirm these observations.