A case of subcortical deafness due to cerebral hemorrhage

Abstract

A 46-year-old right-handed man who had suffered from cerebrovascular attack six years before, suddenly became completely deaf and made no response to spoken words, bell sounds or any other noises. Cortical symptom such as aphasia, alexia or agraphia was not observed. In addition, pure word deafness and auditory agnosia were not recognized in the course of recovery.
Computed tomography demonstrated a sharp defined high density area in the left insula and putamen indicating cerebral hemorrhage and scattered low density area in the right basal ganglia due to old stroke. Anterior horn of the lateral ventricle was compressed and shifted to the left. Pure tone audiometry performed on 13th day after the onset showed that the hearing loss was at the threshold of 40 dB in the right ear and 85 dB (1, 000Hz) in the left ear. On 23th day after the onset, the hearing loss was improved to the level of 20 dB in the right and 10 dB (1, 000 Hz) in the left with the recovery of clinical symptoms.
Results of clinical features and CT findings suggested that severe hearing loss observed in the present case was presumably due to bilateral subcortical lesions, presumably transecting the auditory radiations en route to the cortex. Possible roles of the auditory radiation for so-called cortical deafness have been discussed. Up to date, so-called cortical deafness possibly due to bilateral subcortical lesions has been reported on only 3 cases.