Transtympanic electrocochleography was carried out on 18 syphilitic patients (30 ears were tested) most of whom were suffering from the late onset congenital form of the disease. A diphasic action potential with a large negative summating potential on the descending limb was found in 77.7% of ears; the cochlear microphonic potential was always of small amplitude. While these findings are not pathognomonic of syphilis, they are characteristic and may be explained on pathological grounds.
|