Introduction: Standard vestibular evoked myogenic potentials (VEMP) are widely used in the assessment of vestibular disorders in clinical practice. But studies have shown that role of VEMP alone in the diagnosis of vestibular dysfunction is not entirely satisfactory. In the recent years’ ocular myogenic potentials, produced by the synchronous activity in the extra ocular muscles in response to vestibular stimulation, is being studied extensively for identifying vestibular diseases Aims & Objective: In this study we evaluate the usefulness of acoustic vestibular evoked ocular myogenic potentials (Ac oVEMP) along with traditional cVEMP (Cervical vestibular evoked myogenic potentials) and BAER (Brain stem auditory evoked Response) for diagnosing vestibular neuronitis. Materials and Methods: 100 subjects were included in this study (Group A 50 -normal subjects; Group B – 50 patients with vestibular neuronitis). Ac oVEMP was performed on both the groups and the results were analyzed for difference and statistical significance. Patients in Group B were additionally subjected to cVEMP and BAER. Results: Ac oVEMP in Group A subjects produced n and p response that was consistent and reproducible. There was no inter-aural difference. Ac oVEMP in Group B showed prolongation of n and p latencies when compared with normal subjects (p≤0.01). 23 patients in group B demonstrated abnormal Ac oVEMP (46%) whereas 10 patients in group B had abnormal cVEMP (20%). This was attributed to the more common involvement of superior division of vestibular nerve in vestibular neuronits, which is best tested by Ac oVEMP. Conclusion: Acoustic vestibular evoked ocular myogenic potential (Ac oVEMP) plays an important role as an electrophysiological tool in the diagnosis of vestibular neuronitis.

Keywords: Acoustic Vestibular Evoked Ocular Myogenic Potentials (Ac oVEMP); Vestibular neuronitis; Vestibular nerve divisions; Evoked potentials.