Diagnostic significance of summating potential in sensorineural deafness

The polarity of the summating potential wave induced by electrocochleographical examination has an important bearing upon the pathophysiology or the prognostic evaluation of sensorineural deafness. Electrocochleographical examination was performed on cases of sudden deafness, Ménière's disease, progressive sensorineural deafness, sensorineural deafness due to barotrauma, etc. When the polarity of the summating potential showed an increased negative wave, physiological blockage in sensorineural structures was revealed. In other words, under such conditions sensorineural structures have a potential for activity although hearing acuity was damaged. On the other hand, when the summating potential has an increased positive polarity wave, gradual decrease of the hearing acuity was revealed.