Electrocochleography in the Diagnosis of Endolymphatic Hydrops

Abstract

Extratympanic electrocochleographic findings were compared with the results of the glycerol test and the furosemide test in Meniere's disease. Increased negative summating potentials (SP) were recorded in 25 of the 35 ears (71%), while the glycerol test was positive in 14 of the 25 ears (56%) and the furosemide test was positive in 6 of the 22 ears (27%).
The relationship between the average hearing level at 2 to 8kHz and the increase of negative SP was examined in 35 ears with Meniere's disease. Increased negative SP's were recorded in many patients with mild to moderate deafness. In many of the patients with almost normal hearing and low tone loss with normal hearing above 2kHz, normal SP's were recorded, but no SP appeared in patients with severe deafness.
In the conditions other than Meniere's disease, increased negative SP's were recorded. In some of these, the glycerol test or the furosemide test revealed the existence of endolymphatic hydrops.
The relationship of increased negative SP to endolymphatic hydrops is discussed and the suitability of electrocochleography in the diagnosis of endolymphatic hydrops, compared with the glycerol test and the furosemide test is stressed.