Vestibular Evoked Myogenic Potential as a Tool to Identify Vestibular Involvement in Auditory Neuropathy

Auditory neuropathy is characterized by a unique pattern of hearing loss, absent or severely distorted ABR, preserved OAE, and measurable cochlear microphonics. As the vestibular and cochlear branches are parts of the same fiber bundle system called the vestibulocochlear nerve, it is likely that neuropathy in one (cochlear branch) might also form a feature in the other (vestibular branch). But none of these tests are able to explain the involvement of the vestibular system in these cases. Thus, the present study was undertaken to explore this aspect to determine: (1) the involvement of the vestibular pathway in cases with auditory neuropathy; (2) if there is any relationship between vestibular abnormalities and the symptoms they mimic; and (3) the incidence of vestibular abnormality in patients with auditory neuropathy. Ten subjects (7 male and 3 female) in the age range of 15 to 35 years participated in this study. The test battery administered included pure-tone audiometry, ABR, OAE, Immittance, and VEMP.The results showed: (1) nine out of the 10 subjects showed abnormal or absent VEMP; (2) there is no one-to-one correlation between the abnormal or absent VEMP and the vestibular symptoms that these subjects present; and (3) 80% of the ears with auditory neuropathy showed abnormal VEMP results giving an indication of high incidence of vestibular involvement in the auditory neuropathy population.The present study provides evidence for involvement of the vestibular branch of the VIIIth cranial nerve in a high percentage of the auditory neuropathy population; hence, it is suggested that there is need for vestibular assessment in cases of auditory neuropathy that would help to better understand the disorder. It is also suggested that the term "acoustic neuropathy" be used to indicate those patients in whom only the acoustic nerve is affected and "vestibuloacoustic neuropathy" to label those patients who also show involvement of the vestibular system

Audiology · Auditory neuropathy · Hearing loss · Population · Saccule · Vestibular evoked myogenic potential · Vestibular nerve · Vestibular system · Ear Surgery and Otitis Media · Hearing, Cochlea, Tinnitus, Genetics · Medicine · Vestibular and auditory disorders