OBJECTIVES/HYPOTHESIS: The aim of our study was the objective assessment of endolymphatic hydrops in asymptomatic ears in unilateral M?ni?re's disease with a noninvasive electrophysiological test and investigation of significant clinical signs. The null hypothesis was that there would be no signs of endolymphatic hydrops in the asymptomatic ear.STUDY DESIGN: Prospective study using the traveling wave velocity test for endolymphatic hydrops.METHODS: The traveling wave velocity test was used in conjunction with standard audiological tests to investigate both ears of 181 M?ni?re's patients attending the Medical Research Council Institute of Hearing Research in Southampton, United Kingdom. The test uses derived auditory brainstem responses to estimate the velocity of the cochlear traveling wave that is altered in endolymphatic hydrops. M?ni?re's disease was assessed using Arenberg's five staging criteria. Significant correlations were evaluated using standard statistical methods.RESULTS: Of 100 patients with clinically unilateral M?ni?re's disease, 27% showed evidence of endolymphatic hydrops in their asymptomatic ear. There was a significant correlation between signs of hydrops and the mean air-conduction threshold at 500 Hz.CONCLUSIONS: We recommend that a full assessment of incipient disease in the asymptomatic ear in unilateral M?ni?re's disease should be undertaken before offering any treatment options to patients. Any suspicion of early disease in the asymptomatic ear in unilateral M?ni?re's disease should lead to full electrophysiological assessment to assess the evidence of endolymphatic hydrops in that ear.
Endolymphatic Hydrops Evoked Potentials, Auditory, Brain Stem