Characterizing the Age and Stimulus Frequency Interaction for Ocular Vestibular-Evoked Myogenic Potentials

Effect of Electrode Montage on Frequency Tuning Properties of Air-Conducted Ocular Vestibular-Evoked Myogenic Potential

OBJECTIVES

The use of a 500 Hz tone burst over other frequencies was adopted for the clinical recording of ocular vestibular-evoked myogenic potential (oVEMP) on the basis that this stimulus frequency produces larger response amplitudes (frequency tuning) than the other frequencies. However, the possibility of reflex contamination due to a spatially displaced reference electrode from the muscle of the response origin raises questions about using an infraorbital (IO) montage. Nonetheless, the belly-tendon (BT) montage, which places both the recording electrodes over the inferior oblique muscle, increases the chances of obtaining a response with greater contribution from the inferior oblique muscle. However, whether this response continues to show the frequency tuning to 500 Hz is not known. Therefore, the present study aimed to examine the frequency tuning of oVEMP using various electrode montages.

DESIGN

Thirty-eight young adults underwent simultaneous oVEMP recording from IO, BT, chin-referenced, and sternum-referenced electrode montages in response to 250, 500, 750, 1000, 1500, 2000, 3000, and 4000 Hz tone bursts.

RESULTS

The frequency tuning most often coincided with a 750-Hz tone burst irrespective of the montage, with the BT montage exhibiting significantly higher response rates and larger peak to peak amplitudes than other montages ( p < 0.008). Further, there was a "substantial" agreement on frequency tuning between BT and IO montages.

CONCLUSIONS

With better response rates and response amplitudes yet similar frequency tuning to the IO montage, the BT montage can be a better option for the clinical recording of oVEMP across frequencies.

Development and Standardization of Modified Simultaneous Multifrequency Stimulus for Recording Ocular Vestibular-Evoked Myogenic Potential and Its Interaction with the Alternate Electrode Montages

BACKGROUND

 Simultaneous multifrequency (SiMFy) is a time-saving and reliable stimulus to determine the frequency tuning of ocular vestibular-evoked myogenic potential (oVEMP); however, the absence of 4000 Hz in SiMFy potentially makes it a less potent tool for the diagnosis of superior semicircular canal dehiscence, a pathology with an ever-increasing prevalence. Further, SiMFy was validated using only the infraorbital (IO) electrode montage. However, the recordings obtained using the IO montage might be susceptible to reference contamination introduced by a small separation between the recording electrodes and also susceptible to reflex impurity due to the spatially displaced reference electrode from the inferior oblique muscle, rendering it vulnerable to picking up responses from other muscles. Nonetheless, little is known about the similarities/differences between the SiMFy-induced oVEMPs using alternate montages (belly-tendon [BT], chin-reference [CR], and sternum-reference [SR]) and the nonsimultaneous multifrequency oVEMPs (NSM-oVEMPs) using the IO montage.

PURPOSE OF THE STUDY

 To develop a modified SiMFy stimulus and investigate its effects on frequency tuning of oVEMP using various electrode montages.

RESEARCH DESIGN

 Within-subject experimental design.

STUDY SAMPLE

 Thirty-three healthy adults aged 20 to 30 years.

DATA COLLECTION AND ANALYSIS

 Tone bursts of octave and mid-octave frequencies from 250 to 4000 Hz were generated and concatenated to create the modified SiMFy stimulus. All participants underwent NSM oVEMPs and modified SiMFy oVEMPs using BT, CR, SR, and IO montages simultaneously. The response rate, peak-to-peak amplitude, and frequency tuning were compared between NSM-oVEMP and modified SiMFy oVEMP and also between the electrode montages.

RESULTS

 BT montage recorded the largest amplitude among the montages in NSM stimulation and modified SiMFy stimulation. Although the response rates were comparable, the modified SiMFy produced significantly lower oVEMP amplitudes than the NSM stimulation within each electrode montage (p < 0.05). A moderate-to-strong agreement on frequency tuning existed between the NSM stimuli and modified SiMFy stimulus for all the montages, except for the SR montage.

CONCLUSIONS

 Although the modified SiMFy produces smaller amplitude oVEMPs than the NSM stimulation for the respective montages, its use in combination with the BT montage yields higher response rates and larger peak-to-peak amplitudes than the NSM recording using IO montage.

Effects of Age on the Frequency Amplitude Ratio of Cervical and Ocular Vestibular Evoked Myogenic Potentials

PURPOSE

An increase in the 1000/500 Hz frequency amplitude ratio (FAR) of the cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP, respectively) may serve as a potential biomarker for diagnosing Meniere's disease (MD). However, the aging process can also result in an increased FAR for VEMPs. In older patients, distinguishing whether changes in VEMP FAR are due to MD or aging processes becomes difficult. We aimed to investigate the effects of age on VEMP FARs and establish a FAR-normative range for different age groups.

METHOD

cVEMP and oVEMP were recorded from a total of 106 participants grouped as young, middle-aged, and older adults using air-conducted tone bursts at 500, 750, and 1000 Hz at 125 dB pSPL. The FAR was calculated for the cVEMP and oVEMP for the following frequencies: FAR1 = 1000/500, FAR2 = 1000/750, and FAR3 = 750/500.

RESULTS

A significant age-related effect was observed on the cVEMP FAR. Although the oVEMP FAR showed an increasing trend with age, it was not statistically significant. Age-based normative FAR values are provided.

CONCLUSIONS

Drawing from the normative FAR from this study, there is evidence that the existing MD diagnostic criteria would misidentify a considerable number of older adults. Therefore, to reduce false positives, we recommend a more stringent cVEMP and oVEMP FAR criterion in older adults.

Measurement of Ocular Vestibular Evoked Myogenic Potentials: Nasion Reference Montage as an Alternative to the Clinical Standard Montage

OBJECTIVE

To compare two novel electrode montages for ocular, vestibular evoked myogenic potential using single-nasion reference electrodes with the clinical standard montage.

STUDY DESIGN

Randomized crossover experiment.

SETTING

Tertiary referral center.

PARTICIPANTS

Sixty healthy participants.

INTERVENTION

Normal hearing and vestibular function were confirmed with an extensive test-battery. All ocular, vestibular evoked myogenic potential settings were measured with air-conducted tone bursts at 100-dB normal hearing level and a frequency of 500 Hz. Three electrode montages were measured in randomized order: the clinical standard montage ("S"), the nasion reference montage ("N"), and the nasion reference montage with a more lateral active electrode ("L"). Upgaze was standardized to 35 degrees.

MAIN OUTCOME MEASURES

Detection rate, latency of N1 and P1, peak-to-peak amplitude of N1 and P1, signal-to-noise ratio (SNR), asymmetry ratio (AR), concordance of expert assessment, and reliability.

RESULTS

All electrode montages showed detection rates greater than 90%. Latencies for "L" were shorter than for "S" and "N." Amplitudes and SNR for "S" and "N" were higher than for "L," whereas the values for "S" and "N" did not differ significantly. For AR, no significant differences between the montages were assessed. Concordance of experts ranged from 78% for "L" and 89.8% for "N." All montages provided excellent day-to-day reliability (intraclass correlation coefficient ≥0.9) for amplitudes and SNR.

CONCLUSIONS

Montage N could be a useful alternative to the clinical standard montage: although results are roughly equivalent, montage N requires one less electrode to do so.

Utility of Inter-Frequency Amplitude Ratio of Vestibular-Evoked Myogenic Potentials in Identifying Meniere's Disease: A Systematic Review and Meta-Analysis

OBJECTIVES

A recently devised parameter of vestibular-evoked myogenic potential (VEMP) based on the principles of frequency tuning is the inter-frequency amplitude ratio (IFAR). It refers to the ratio of the amplitude of 1000 Hz tone burst evoked VEMP to 500 Hz evoked tone burst. A pathology like Meniere's disease changes the frequency response and alters the frequency tuning of the otolith organs. Because IFAR is based on the principle of frequency tuning of VEMP, it is likely to help identify Meniere's disease. Few studies in the last decade have investigated the utility of IFAR in identifying Meniere's disease. However, a systematic review and a meta-analysis on IFAR in Meniere's disease are lacking. The present study investigates whether the IFAR of VEMP helps identify Meniere's disease and differentiates it from healthy ears and other vestibular pathologies.

DESIGN

The present study is a systematic review and a meta-analysis. The studies investigating the IFAR of cervical and ocular VEMPs in Meniere's disease, healthy controls, and other vestibular pathologies were searched across research databases such as PubMed, Science Direct, and Scopus. The search strategy was developed using the PICO (population, intervention, comparison, and outcomes) format, and Medical Subject Headings (MeSH) terms and Boolean operators were employed. The systematic review was performed using the Rayyan software, whereas the Review Manager software was used to carry out the meta-analysis. A total of 16,605 articles were retrieved from the databases. After the duplicate removal, 2472 articles remained. These were eliminated using title screening, abstract screening, and full-length inspections. A total of nine articles were found eligible for quality assessment and meta-analysis, and the New Castle-Ottawa Scale was used for quality assessment. After the data extraction, 24 six articles were found to have the desired data format for the meta-analysis.

RESULTS

The results showed significantly higher IFAR in the affected ears of individuals in the Meniere's disease group than in the control group's unaffected ears. There was no significant difference between the unaffected ears of individuals in the Meniere's disease group and the ears of the control group. The only study on Meniere's disease and benign paroxysmal positional vertigo found significantly larger ocular VEMP IFAR in ears with Meniere's disease than in benign paroxysmal positional vertigo.

CONCLUSIONS

This systematic review and meta-analysis found IFAR efficient in differentiating Meniere's disease from healthy controls. We also found an enhanced IFAR as a potential marker for Meniere's disease. However, more investigations are needed to confirm the utility of an enhanced IFAR value in the exclusive identification of Meniere's disease.

Clinical and VEMPS Characteristics of Benign Recurrent Vertigo With Cochlear Symptoms and Migraine

Objectives: To explore the clinical manifestations and vestibular-evoked myogenic potential (VEMP) characteristics in patients diagnosed with benign recurrent vertigo (BRV) accompanied by cochlear symptoms or migraine history. Methods: A total of 34 patients were diagnosed with BRV (57 ears) and 30 healthy volunteers (60 ears) were recruited. They were divided into 4 groups: Group A consisted of 17 patients diagnosed as BRV with cochlear symptoms (21 ears), Group B consisted of 11 patients diagnosed as BRV with migraine history (22 ears), and Group C consisted of 7 patients with BRV without cochlear symptoms and migraine history (14 ears). Group D, as a Normal control (NC) group, consisted of 30 healthy volunteers without a history of migraine and cochlear symptoms. Detailed consultations and VEMP testing were performed separately. The VEMPs elicitation rate, amplitude ratio at different frequencies and amplitude statistics were compared and analyzed among the 4 groups. Results: The amplitudes of cervical vestibular evoked myogenic potential (cVEMP) have significant differences between Groups D and A, and Group C, under 500 Hz (PAD = .017, PBD = .052, PCD = .044), but the amplitudes of cVEMP have significant differences between Groups D and A, and Group B under 1000 Hz, respectively (PAD = .008, PBD = .020, PCD = .119). The amplitudes of ocular vestibular evoked myogenic potential (oVEMP) have significant differences between Groups D and A, and Group B, under 500 Hz, respectively (PAD = .029, PBD = .005, PCD = .198). oVEMP amplitudes significantly differ between Groups D and A under 1000 Hz (PAD = .049, PBD = .079, PCD = .103). The statistical difference was absent in elicit rates of cVEMP and oVEMP between the NC and experimental groups (cVEMP: PAD = .525, PBD = .917, PCD = .374; oVEMP: PAD = .678, PBD = .523, PCD = .427). Moreover, there is no significant difference between the NC group and experimental groups among VEMPs and VEMP frequency amplitude ratio (P > .05). Conclusion: VEMPs could be a diagnostic indicator for BRV patients with cochlear symptoms. The pathogenesis of BRV may be related to damage to the otolithic apparatus.

Effects of aging on ocular vestibular-evoked myogenic potential using ER-3A insert earphone and B81 bone vibrator

Purpose

Aging is a process associated with degeneration and dysfunction of peripheral vestibular system or apparatus. This study aimed to investigate the influence of aging on ocular vestibular-evoked myogenic potential (oVEMP) response rates and recording parameters using the B81 bone vibrator and compare them with air conduction stimuli (ACS) oVEMP response characteristics.

Methods

In 60 healthy participants aged 10–71 years (mean age 39.9; 29 male participants), the oVEMP response was elicited using a B81 bone vibrator and an ER-3A insert earphone. The effects of age and stimulus on oVEMP response rates and recording parameters were evaluated.

Results

Response rates and amplitudes declined with aging using either ACS or bone-conducted vibration (BCV) stimulation, particularly in individuals over 60 years of age, whereas thresholds increased and N1 latencies were prolonged. BCV showed fewer risks of absent oVEMP response than ACS (p = 0.002). BCV acquired higher amplitudes (p &lt; 0.001), lower thresholds, and shorter N1 and P1 latencies (all p &lt; 0.001) than ACS.

Conclusions

The absence of an oVEMP response may be attributed to aging rather than a concurrent vestibular disorder. B81-BCV likely produces higher mechanical drives to the vestibular hair cells at safer and non-traumatic levels compared with ACS and therefore may be more likely to evoke a response in the elderly cohort, whose vestibular function and mechanical sensitivity have declined. Thus, B81-BCV stimulation is more effective and safer to elicit oVEMPs, and it should be recommended when ACS fails in the clinic, particularly in the elderly population.

Effects of Age and Middle Ear on the Frequency Tuning of the cVEMP and oVEMP

BACKGROUND

Upward shift in the air conducted (AC) frequency tuning of vestibular evoked myogenic potentials (VEMPs) as an effect of aging is hypothesized to be due to the microstructural stiffening changes in the inner ear. However, with an AC stimulus, it may be possible that the shift in the frequency tuning of VEMPs as an effect of aging may also be due to contributions from the middle ear.

PURPOSE

The main aim of this study was to examine the effects of age on the frequency tuning of the cervical VEMP (cVEMP) and ocular VEMP (oVEMP) and determine the role of middle ear transmission characteristics in shaping these effects.

RESEARCH DESIGN

Standard group comparison.

STUDY SAMPLE

One-hundred seven participants divided in three groups: young adult, middle-age, and older adults with "normal" middle ear and negative history of neurological or vestibular complaints.

DATA COLLECTION AND ANALYSES

Middle ear measures included static admittance and middle ear resonant frequency. cVEMP and oVEMPs were elicited with AC tone bursts at 500, 750, and 1,000 Hz.

RESULTS

No significant effect of age was observed on any of the middle ear measures. There was a significant effect of age on the amplitude of the cVEMP, but this effect was frequency specific. The age-related reduction in cVEMP corrected amplitude was only observed when the eliciting stimulus was 500 or 750 Hz, with no significant effect observed with a 1,000 Hz stimulus. For the oVEMP, the effects of age were apparent at all stimulus frequencies. We also observed a general upward shift in the frequency tuning of both the cVEMP and oVEMP for middle-age and older adults, with 750 and 1,000 Hz yielding higher response rates and larger amplitudes among middle-aged and older adults. Measurements of middle ear did not significantly contribute to the observed findings.

CONCLUSIONS

The upward shift in frequency tuning of VEMPs among middle age and older adults could be due to the changes in the vestibular system and not from the middle ear. These results support the use of different frequency stimuli (i.e., 750 or 1,000 Hz) to elicit a VEMP if a response is absent using a 500 Hz stimulus, especially in patients over the age of 40.

Simultaneous Multifrequency (SiMFy) Stimulus: A Novel and Reliable Stimulus for Frequency Tuning of Ocular Vestibular-Evoked Myogenic Potentials

BACKGROUND

Frequency tuning of ocular vestibular evoked myogenic potential (oVEMP) refers to the frequency of tone burst that produces the largest amplitude oVEMP. There is an ever-growing pool of published studies that found the frequency tuning of oVEMP distinctly different in Ménière's disease than the age-matched controls and benign paroxysmal positional vertigo. However, recording oVEMP in response to many frequencies makes an already lengthy vestibular test battery even more cumbersome and time-consuming.

PURPOSE

The aim of this study was to develop a novel time-saving stimulus that produces reliable results.

RESEARCH DESIGN

Prospective study.

STUDY SAMPLE

The study included 25 young, healthy adults.

DATA COLLECTION

The tone-bursts of 2000, 1500, 1000, 750, 500, and 250 Hz were generated and sequenced in this order to prepare a stimulus for simultaneous multifrequency (SiMFy) oVEMP. The response parameters of SiMFy and conventional oVEMP methods were compared.

RESULTS

No significant difference in peak-to-peak amplitude and frequency tuning existed between conventional and SiMFy oVEMP (p > 0.05). SiMFy had better test-retest reliability and was less time-consuming than the conventional oVEMP.

CONCLUSIONS

SiMFy is a time-saving and reliable stimulus for obtaining frequency tuning of oVEMP with no compromise on the outcomes. It can be immediately applied in most commercially available evoked potential systems with a facility for loading an external stimulus.

Simultaneous Multifrequency (SiMFy) Stimulus: A Novel and Reliable Stimulus for Frequency Tuning of Ocular Vestibular-Evoked Myogenic Potentials

Background Frequency tuning of ocular vestibular evoked myogenic potential (oVEMP) refers to the frequency of tone burst that produces the largest amplitude oVEMP. There is an ever-growing pool of published studies that found the frequency tuning of oVEMP distinctly different in Ménière's disease than the age-matched controls and benign paroxysmal positional vertigo. However, recording oVEMP in response to many frequencies makes an already lengthy vestibular test battery even more cumbersome and time-consuming.

Purpose The aim of this study was to develop a novel time-saving stimulus that produces reliable results.

Research Design Prospective study.

Study Sample The study included 25 young, healthy adults.

Data Collection The tone-bursts of 2000, 1500, 1000, 750, 500, and 250 Hz were generated and sequenced in this order to prepare a stimulus for simultaneous multifrequency (SiMFy) oVEMP. The response parameters of SiMFy and conventional oVEMP methods were compared.

Results No significant difference in peak-to-peak amplitude and frequency tuning existed between conventional and SiMFy oVEMP (p > 0.05). SiMFy had better test–retest reliability and was less time-consuming than the conventional oVEMP.

Conclusions SiMFy is a time-saving and reliable stimulus for obtaining frequency tuning of oVEMP with no compromise on the outcomes. It can be immediately applied in most commercially available evoked potential systems with a facility for loading an external stimulus.

Similarities and Differences Between Vestibular and Cochlear Systems - A Review of Clinical and Physiological Evidence

The evoked response to repeated brief stimuli, such as clicks or short tone bursts, is used for clinical evaluation of the function of both the auditory and vestibular systems. One auditory response is a neural potential - the Auditory Brainstem Response (ABR) - recorded by surface electrodes on the head. The clinical analogue for testing the otolithic response to abrupt sounds and vibration is the myogenic potential recorded from tensed muscles - the vestibular evoked myogenic potential (VEMP). VEMPs have provided clinicians with a long sought-after tool - a simple, clinically realistic indicator of the function of each of the 4 otolithic sensory regions. We review the basic neural evidence for VEMPs and discuss the similarities and differences between otolithic and cochlear receptors and afferents. VEMPs are probably initiated by sound or vibration selectively activating afferent neurons with irregular resting discharge originating from the unique type I receptors at a specialized region of the otolithic maculae (the striola). We review how changes in VEMP responses indicate the functional state of peripheral vestibular function and the likely transduction mechanisms allowing otolithic receptors and afferents to trigger such very short latency responses. In section "ELECTROPHYSIOLOGY" we show how cochlear and vestibular receptors and afferents have many similar electrophysiological characteristics [e.g., both generate microphonics, summating potentials, and compound action potentials (the vestibular evoked potential, VsEP)]. Recent electrophysiological evidence shows that the hydrodynamic changes in the labyrinth caused by increased fluid volume (endolymphatic hydrops), change the responses of utricular receptors and afferents in a way which mimics the changes in vestibular function attributed to endolymphatic hydrops in human patients. In section "MECHANICS OF OTOLITHS IN VEMPS TESTING" we show how the major VEMP results (latency and frequency response) follow from modeling the physical characteristics of the macula (dimensions, stiffness etc.). In particular, the structure and mechanical operation of the utricular macula explains the very fast response of the type I receptors and irregular afferents which is the very basis of VEMPs and these structural changes of the macula in Menière's Disease (MD) predict the upward shift of VEMP tuning in these patients.

Effect of advancing age on inter-frequency amplitude ratio of ocular vestibular evoked myogenic potentials

OBJECTIVE

The inter-frequency amplitude ratio (IFAR) is the ratio of the amplitude of 1000-Hz tone-burst evoked ocular vestibular evoked myogenic potential (oVEMP) to the 500 Hz tone-burst evoked oVEMP. Since IFAR is an amplitude-based parameter, and the amplitudes of oVEMP for different frequencies are differentially affected by ageing, IFAR could potentially be affected by the ageing process. Therefore, we aimed to examine the effects of ageing on the IFAR of oVEMPs.

DESIGN

Multiple static groups comparison.

STUDY SAMPLE

We recorded oVEMPs for 500 Hz and 1000 Hz tone-bursts from 270 healthy individuals, each included in one of the six age groups.

RESULTS

The IFAR was significantly larger in the ≥60 years age group than the age groups up to 49 years. Furthermore, the IFAR in the 50-59 years age group was significantly larger than all the other age groups up to 39 years. There was a significant positive correlation between age and IFARs (p < 0.01).

CONCLUSIONS

IFAR, a sensitive tool in the test battery for the diagnosis of Meniere's disease, is affected even in healthy individuals due to ageing; hence its cautious interpretation is recommended when evaluating adults >50 years of age who are suspected of having Meniere's disease.

Vestibular Evoked Myogenic Potential (VEMP) Testing for Diagnosis of Superior Semicircular Canal Dehiscence

Superior semicircular canal dehiscence is a bony defect of the superior semicircular canal, which can lead to a variety of auditory and vestibular symptoms. The diagnosis of superior semicircular canal dehiscence (SCD) can be challenging, time consuming, and costly. The clinical presentation of SCD patients resembles that of other otologic disease, necessitating objective diagnostics. Although temporal bone CT imaging provides excellent sensitivity for SCD detection, it lacks specificity. Because the treatment of SCD is surgical, it is crucial to use a highly specific test to confirm the diagnosis and avoid false positives and subsequent unnecessary surgery. This review provides an update on recent improvements in vestibular evoked myogenic potential (VEMP) testing for SCD diagnosis. Combining audiometric and conventional cervical VEMP results improves SCD diagnostic accuracy. High frequency VEMP testing is superior to all other methods described to date. It is highly specific for the detection of SCD and may be used to guide decision-making regarding the need for subsequent CT imaging. This algorithmic sequential use of testing can substantially reduce radiation exposure as well as cost associated with SCD diagnosis.

Intersession Variations in Frequency Tuning of Ocular Vestibular Evoked Myogenic Potentials in Healthy Individuals

Objective Frequency tuning of ocular vestibular evoked myogenic potential (oVEMP), which is the stimulus frequency corresponding to the largest oVEMP amplitude, has been used to diagnose cases with Ménière's disease and differentiate them from cases with benign paroxysmal positional vertigo with a high degree of sensitivity and specificity. However, this measure of oVEMP is carved out of the peak-to-peak amplitude of oVEMP, and studies on test-retest reliability of amplitude of oVEMP have shown moderate-to-excellent reliability of amplitude. This would theoretically render the frequency tuning of oVEMP susceptible to variations across multiple recordings. This being the case, erroneous conclusions regarding the presence of Ménière's disease could be made if the frequency tuning varies between recordings. However, there is no published report regarding the test-retest reliability of frequency tuning measure of oVEMP even in healthy individuals, to the best of our knowledge. Therefore, this study aimed to study the test-retest reliability of frequency tuning of oVEMP in healthy individuals. Method The study included 20 healthy adults in the age range of 18-25 years. All participants underwent oVEMP recording in 4 different sessions, with each session consisting of oVEMP recording for octave and midoctave tone-burst frequencies from 250 to 2000 Hz. Results The results revealed no significant difference in frequency tuning of oVEMP among the sessions (p > .05). The intraclass correlation coefficient for frequency tuning data was found to be .857. Conclusion The frequency tuning of oVEMP has excellent test-retest reliability and therefore lends itself to applications requiring multiple sessions of recording.

Vestibular evoked myogenic potentials in practice: Methods, pitfalls and clinical applications

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Vestibular evoked myogenic potentials (VEMPs) are used to test the otolith organs in patients with vertigo and imbalance.

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This review discusses the optimal procedures for recording VEMPs and the pitfalls commonly encountered by clinicians.

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Better understanding of VEMP methodology should lead to improved quality of recordings.

Vestibular evoked myogenic potentials (VEMPs) are a useful and increasingly popular component of the neuro-otology test battery. These otolith-dependent reflexes are produced by stimulating the ears with air-conducted sound or skull vibration and recorded from surface electrodes placed over the neck (cervical VEMPs) and eye muscles (ocular VEMPs). VEMP abnormalities have been reported in various diseases of the ear and vestibular system, and VEMPs have a clear role in the diagnosis of superior semicircular canal dehiscence. However there is significant variability in the methods used to stimulate the otoliths and record the reflexes. This review discusses VEMP methodology and provides a detailed theoretical background for the techniques that are typically used. The review also outlines the common pitfalls in VEMP recording and the clinical applications of VEMPs.