Glycerol Affects Vestibular-Evoked Myogenic Potentials and Pure-Tone Hearing in Patients with Meniere's Disease

Abstract

Conclusion: The pure-tone audiometry results following glycerol administration indicated a positive effect on cochlear endolymphatic hydrops. Glycerol cervical vestibular-evoked myogenic potential (cVEMP) tests are a useful means of diagnosing saccular hydrops. There was no correlation between cVEMP and audiological results. Objective: To document the changes in pure-tone hearing outcomes and cVEMPs in patients with Meniere's disease (MD) and 10 healthy volunteers before and after oral administration of glycerol. Methods: Twenty-nine study group subjects were chosen with complaints of vertigo. cVEMP testing and pure-tone hearing level testing were performed before and at 1, 2, and 3 h after administration of glycerol. Results: The means of the latencies, amplitudes, and difference ratio in 20 normal subject ears were determined. Based on these values, 9/29 MD-affected (MDA) ears (31%) had a unilaterally absent cVEMP. Compared with difference ratio values of the control groups there were significant differences in both latencies and amplitudes in MDA ears after glycerol administration. Before glycerol administration, there were significant differences between control and MDA ears on mean values of pure-tone hearing outcomes. Twenty patients in the MDA group showed significant pure-tone hearing outcomes after glycerol administration.