The Importance of Electrocochleography in Diagnosis of Meniere's Disease

Electrocochleography plays an important role in the diagnosis of hearing disorders. In Meniere's disease, the value of negative summating potential (SP) relative to the action potential (AP) is known to be much larger than in normal hearing and other sensorineural hearing loss. However, since it is unknown whether or not the finding of dominant negative SP (DNSP) is characteristic in Meniere's disease, its practical value for differentiation of Meniere's disease remaines uncertain.In this paper, for each disease accompanied by dizziness and or hearing disorders, the proportion of cases with DNSP was determined. Acoustic click (105dB SPL, 125msec. intervals) were used as stimuli, and the output of the cochlea was picked up by a silver-ball electrode placed on the surface of the ear drum. The amplified responses were taken 1024 times averaged and read out on an oscillograph. Materials included 160 patients with dizziness and/or hearing disturbances, including 91 with Meniere's disease, 7 with cochlear Meniere's disease, 13 with vestibular Meniere's disease, 1 with luetic labyrinthitis, 7 with sudden deafness, 14 with sensorineural hearing loss, 12 with dizziness and so on. DNSP was frequently observed in Meniere's disease(67%), cochlear Meniere's disease (100%), and sudden deafness(28%), in which endolymphatic hydrops were at least partially suspected. In other diseases accompanied by dizziness and/or hearing disturbances, DNSP was rare. Therefore, DNSP is considered to indicate certain groups of disease with endolymphatic hydrops. Meniere's disease of a shorter duration revesled DNSP less often. DNSP showed a tendency to remain after the acute stage had passed, i. e. in the stage of remission.