Prognosis of Sudden Deafness Studied by Electrocochleography

Abstract

20 patients with sudden deafness were examined by electrocochleography (ECochG).The cochlear potentials such as AP, CM and SP were investigated both at the early stage of the disease and 2 to 4 weeks later. There was a significant difference in the cochlear potentials between the cases with remarkable hearing improvement and with improvement. In all cases whose SP/AP ratio was more than 0. 27, hearing improvement was obtained. The SP/AP ratio returned normal (about 0. 25), after the hearing recovery. It was concluded that the SP/AP ratio in ECochE might be very helpful in studying the prognosis of sudden deafness.

Pathophysiology and Prognosis of Sudden Deafness with Special Reference to the N₁ Latency

“…Review of the literature shows that domi nant -SP, AP high amplitude [19], SP/AP ratio above 0.27 [22], and high amplitude and unchanged latency of AP [23] in ECochG indicate the good hearing recovery, and the latency prolongation and no detect ability of N i are the signs of poor prognosis [24],…”