2021 Volume 62 Issue 3 Pages 252-262
A right-handed 73-year-old man developed sensory aphasia due to a left temporoparietal infarction after a previous lacunar infarction of the right putamen. His aphasia improved rapidly, but as he also had abrupt-type high-frequency central hearing loss, pure word deafness was suspected. We assessed phoneme recognition in his left and right ears due to the difference in lesions in the left and right hemispheres. In the early onset stage, his performance on speech audiometry of the right ear declined, but the performance of the left ear declined gradually. We examined confusion matrices of phoneme perception errors from speech audiometry in the left and right ears. In both ears, but especially in the right ear, many confusions in phoneme perception were present where Japanese consonants and vowels were misheard as /r/. As a characteristic of pure word deafness, it is possible that the phonological characteristics of consonants and vowels could not be grasped, and an ambiguous /r/ was guessed and heard differently. In the left ear, there was an increase in hearing errors with similar articulation styles and points, and nasalization of low-frequency sounds. There was some damage to the neural connections near the acoustic radiation around the right putamen. Furthermore, as changes in auditory central nerves due to aging were also involved, we postulated that those led to the symptoms of abrupt-type high-frequency hearing loss due to central nervous system disorders.
