FREQUENCY-ANALYSIS OF EVOKED OTOACOUSTIC EMISSIONS IN MENIERES-DISEASE

Our study was designed to establish a diagnostic significance in Meniere's disease by means of evoked otoacoustic emissions (EOAEs). EOAEs were recorded from patients with Meniere, and the ''main frequency'' of the emissions, which shows the maximum peak in the frequency spectrum, was examined as a variable. The main frequencies in ears with Meniere ranged mainly from 0.8 kHz to 1.1 kHz and were to be found at lower frequencies than in ears with normal hearing whose range was mainly from 1.0 kHz to 1.6 kHz. Furthermore, in some ears with Meniere, the main frequencies changed from lower to higher after administration of osmotic diuretics such as glycerol or isosorbide. On the basis of these results it was speculated that in ears with Meniere, lower frequency dominant emissions might be elicited by modification of the basilar membrane in endolymphatic hydrops and that the main frequencies might change from lower to higher with reduction of endolymphatic hydrops induced by osmotic diuretics. It was considered that the EOAE testing might be useful for a diagnosis of endolymphatic hydrops in Meniere.