Diagnosis of Meniere's disease by electrocochleography

Abstract

The negative summating potential (-SP) and action potential (AP) were recorded by extratympanic electrocochleography in patients with Meniere's disease. The -SP amplitude and the ratio of -SP amplitude to AP amplitude (-SP/AP ratio) were significantly larger in Meniere ears than in normal ears or ears with hair cells damaged by streptomycin or kanamycin or by noise. An increased -SP/AP ratio was observed more often in ears with endolymphatic hydrops, as in Meniere's disease (58 of 94 ears, 62%) or sensorineural hearing loss due to syphilis (4 of 7 ears, 57%) than in ears with hearing loss of other origins. The results demonstrate the usefulness of electrocochleography [in the diagnosis of Meniere's disease.
An increased -SP/AP ratio and a positive glycerol test was recorded in 32 of 51 ears (63%) and 26 of 51 ears (51%), respectively. In 15 of 51 ears (29%) both tests were positive, and in 43 of 51 ears (84%) one of tests was positive. The incidence of an increased -SP/AP ratio was higher in ears with a moderate to severe hearing loss at high frequencies, whereas the glycerol test was more often positive in ears with a moderate to severe hearing loss at low frequencies. The difference in selectivity by the method makes the combination of both tests useful in the diagnosis of Meniere's disease.