Assessment of otolith mediated neural reflexes through cervical and ocular vestibular evoked myogenic potentials in individuals with auditory neuropathy spectrum disorders

Masseter and cervical vestibular evoked myogenic potentials in individuals with auditory neuropathy

OBJECTIVE

This study aimed to explore the functional integrity of vestibulo-masseteric and sacculo-collic reflex pathways in individuals with Auditory Neuropathy (AN). The study also aimed at finding the correlation between mVEMP and cVEMP response parameters for AN and healthy individuals.

DESIGN

Standard group comparison research design.

STUDY SAMPLE

Individuals with AN (n = 20); age-gender matched healthy individuals (n = 20) were recruited. Each participant underwent routine audiological evaluation; mVEMP and cVEMP testing. mVEMP and cVEMP were recorded using 500 Hz tone burst stimulus for all the participants.

RESULTS

Most of the AN individuals had no mVEMP (ipsilateral & contralateral - 60%; bilateral - 50%) and cVEMP (60%) responses. There was no significant association (p > 0.05) between the duration of AN with mVEMP and cVEMP findings. However, a significant correlation (p < 0.05) was found for EMG rectified amplitude of mVEMP and cVEMP in AN.

CONCLUSION

The results of this study suggested an impaired function of the vestibulomassteric and sacculocollic reflex pathways in individuals with AN. Vestibular evaluation should be included as a part of the regular test battery for individuals with AN.

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.

Relative efficacy of veria and mastoidectomy techniques of cochlear implantation in preservation of sound-induced saccular responses

OBJECTIVE

Cochlear implantation (CI) is a safe technique to give hearing sensation to a person with hearing impairment. The present study aimed to compare the two surgical approaches of CI, mastoidectomy and veria, for their effects on saccular function assessed using cervical vestibular-evoked myogenic potential (cVEMP).

DESIGN

Multiple group time series design.

STUDY SAMPLE

The study included 63 children (3-8 years old) who underwent CI using veria technique (n = 20) and mastoidectomy approach (n = 43). The 500-Hz tone-burst evoked cVEMP were recorded on three occasions- a day before CI surgery, a day after the device switch-on and 4 months after the switch-on.

RESULTS

The post-implant results revealed the absence of cVEMP in nearly 40% of the participants. The amplitudes were significantly lower at the time of the switch-on and at the 4-months follow-up period (p < 0.05). Among the participants undergoing CI using mastoidectomy approach, amplitudes were significantly larger after surgery than those undergoing surgery using veria technique (p < 0.05).

CONCLUSIONS

The saccular responses are better preserved with the mastoidectomy technique than the veria technique for CI surgery.

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.