Sudden sensorineural hearing loss: electrocochleographic findings in 70 patients.

The results of transtympanic ECochG in 70 patients with sudden sensorineural deafness are presented. ECochG was compared with traditional methods of audiometry as a means of deciding whether the deafness was mainly cochlear or retrocochlear. It was found to make a useful and sometimes unique contribution. ECochG gave a definite localization of the deafness in 22 out of 23 patients in whom conventional methods of audiometry had produced equivocal results and was also found to be extremely valuable in 17 patients with "dead" ears. Electrical stimulation of the cochlea may have a prognostic value in cases of sudden retrocochlear deafness. A rational approach to the treatment of sudden deafness depends on precise knowledge of the aetiology and pathology: accurate localization of the site of the lesion is a convenient first step.