[Motor amusia following a right temporal lobe hemorrhage--a case report]

A 65-year-old female was admitted to our hospital because of left hemiparesis with sudden onset one week before. She was congenitally right-handed. She had been a teacher of Japanese string instrument (samisen) playing and been able to sing Japanese traditional songs well. A tape on which she had recorded her songs one year before the admission also proved her to be a good singer. Neurological examination on admission revealed almost normal findings except for minimal weakness in her left hand fingers. Right temporal lobe hemorrhage was revealed by CT scan. One month after the admission, she complained that she was unable to sing her songs and to play samisen as she used to do. Her intelligence was normal (WAIS VIQ116, PIQ108) and there were no abnormal findings as follows: aprosodia, aphasia, agraphia, memory disturbance, agnosia and ideational, ideomotor, constructional or limb-kinetic apraxia. She could point out her errors while singing. However, musical receptive function was slightly disturbed with tonal memory in Seashore test. When she was asked to sing a song without any instrumental support, she hummed a melody occasionally with wrong pitch, but rhythmically. After hearing a song she knew well, she reproduced it with slight improvement. With the vocal or the instrumental accompaniment, she could sing fairly well. She had some mistakes of pitch while playing a samisen. MRI was performed one year and a half after the brain hemorrhage. It displayed a thin linear of hematoma in the white matter of the right upper temporal and transverse gyrus. It was proved in our case that motor amusia with minimal musical receptive dysfunction could appear following a cerebral lesion and musical function might be independent of intelligence or verbal function.