Cervical and Ocular Vestibular Evoked Myogenic Potentials Test Results in Individuals with Auditory Neuropathy Spectrum Disorders

Abstract

Auditory neuropathy spectrum disorder is a clinical disorder where the outer hair cell functioning is intact but the functioning of the auditory nerve is affected. Since, the 8th nerve is constituted by both the auditory and vestibular branch of nerve fibers, there are chances that the vestibular nerve might also be affected. Hence, the current study was carried out in order to determine the functioning of vestibular nerve in individuals with auditory neuropathy. A total of 11 participants were considered for the current study. Cervical vestibular evoked myogenic potentials (cVEMPs) and ocular vestibular evoked myogenic potentials (oVEMPs) were administered using the conventional protocol. In all the participants (100%) the oVEMPs were absent whereas in 20 ears out of 22 ears tested (90.90%) the cVEMPs were absent. The results of the present study indicate a high incidence of vestibular involvement in individuals with auditory neuropathy spectrum disorders. Also, it necessitates the inclusion of vestibular tests in the test battery used to assess individuals with auditory neuropathy spectrum disorder.

Prevalence of vestibular symptoms in individuals with auditory neuropathy spectrum disorder – A retrospective study

“…Interestingly, the results of the study showed that In addition, ocular vestibular evoked myogenic potential are also affected and is suggestive of abnormal superior vestibular nerve functioning (8). The neuropathy may not be restricted only to the auditory branch or the vestibular branch of the eighth cranial nerve.…”

“…Vertigo is also one of the symptoms reported by individuals with ANSD. These individuals also exhibit vestibular neuropathy along with auditory difficulties (6)(7)(8).The individuals with ANSD are also reported to have vestibular neuropathy along with auditory difficulties (6)(7)(8).…”

“…The involvement of the vestibular branch in individuals with ANSD is extensively reported in the literature (6)(7)(8)(9). Kumar et al(6) suggested using the terminology "vestibuloacoustic neuropathy" in individuals who have both auditory and vestibular involvement.…”

“…Sazgar et al (9) reported that isolated auditory neuropathy or vestibular neuropathy is rare and the most common pathology is "audio-vestibular neuropathy" affecting both branches of the eighth cranial nerve. Sinha, Shankar and Raja (8) reported that cervical and ocular vestibular evoked myogenic potentials (VEMP) were abnormal in individuals with ANSD. Sinha et al (7) showed that VEMP were absent and caloric tests showed hypofunctional responses in individuals with ANSD.This suggested involvement of both the inferior and superior vestibular nerve in individuals with ANSD.…”

Vestibular-Evoked Myogenic Potential Testing in Vestibular Localization and Diagnosis

“…105,106 A later study involving oVEMPs showed a similar pattern. 107 Because the patients had auditory neuropathy, it was assumed the site of the lesion was the vestibular nerve. A more recent study looked specifically at patients with Charcot-Marie-Tooth (CMT) disease, a hereditary polyneuropathy, with confirmed involvement of the peripheral nerves.…”