[Auditory brainstem response and extratympanic recorded electrocochleography in patients with multiple and severe...

Nine patients ranged between 5 months and 35 years (means 14 years) of age with multiple and severe disabilities were comparatively studied, on extra-tympanic recorded compound action potential (AP) of electrocochleography and auditory brainstem response (ABR). Both ABR and AP were obvious in 3 patients with clear auditory behavioral responses. The ABR was not recorded to high intensity click stimuli in six patients without visible auditory behavioral responses. Four of the 6 cases showed undetectable AP and the 2 rest of the 6 cases showed abnormal but discernible AP. In two cases with history of the anoxic encephalopathy, AP was recorded but ABR was not detected in one case, and in the other, neither AP nor ABR was recorded. At least two different levels of lesions could be differentiated in cases without detectable ABR by using extra-tympanic recorded electrocochleography in these kinds of severely handicapped patients.