Clinical neurophysiological examination of deafness associated with juvenile motor neurone disease.

Three patients with the syndrome of progressive severe deafness, associated with juvenile onset of motor neurone disease, were examined using conventional audiometry and brainstem auditory evoked response (BAER) recordings, and electrocochleographic recordings were made in two of them. Findings indicate that the deafness had resulted from loss of acoustic nerve fibers and/or sensory cells of the spiral ganglion.