両側被殻出血により両耳聾となった1症例—Cortical deafnessについての考察

CORTICAL DEAFNESS FOLLOWING BILATERAL HYPERTENSIVE PUTAMINAL HEMORRHAGE

　抄録　両側被殻出血で両耳聾となった症例を報告し，cortical deafnessについて考察した。症例は69歳右利きの男性で，はじめ左被殻出血で右半身不全麻痺と右耳の聴力低下をきたし，それが進行して6ヵ月後に右耳聾となり，2年後に右被殻出血を生じて左半身不全麻痺と両耳完全聾となった。Audiogramは骨導，気導共にscale outで，聴性脳幹反応は両耳共に正常パターンで，middle latency responseでは右耳のみにPo波の出現をみた。Pa波は両耳共に確認出来なかった。自発言語，書字理解は良好で，精神機能も正常で最近はある程度の読唇術を習得して筆談を交えて会話を行っている。聾となった機序は，同じような障害部位で聾となった皮質下梗塞症例の剖検所見と本症例のCT所見から判断して，両側被殻出血による聴放線および内側膝状体の破壊によるものと考えている。また本症例の所見からヒトの聴覚路は対側支配優位と考えられる。脳内出血により両耳完全聾となった症例の報告は本症例が最初と思われる。

A case of cortical deafness is reported, which was caused by two episodes of bilateral hyper-tensive putaminal hemorrhage. Such a case has not appeared in literature up to this time.

The patient was a right-handed, 69-year-old man, admitted to us after the stroke with right hemi-paresis and disturbance of consciousness. CT scans showed right putaminal hemorrhage. After re-covery of consciousness, the patient complained of hearing diffuculty of the right ear. The right hemiparesis improved and he was followed am-bulatorily after two months hospitalization. He returned to his work and was able to drive a car. His hearing difficulty of the right ear pro-gressed and became stone deaf six months after onset of the initial stroke. Two years after the first stroke, he was attacked by the second stroke with left hemiparesis. CT scans showed left putaminal hemorrhage larger than the previous one in the right. When the patient recovered con-sciousness, he complained of total deafness. Audiometry test showed that hearing was lost completely to both high and low notes, and there was absence of bone conduction bilaterally. Auditory brain stem response test revealed normal pattern from wave I through wave V bilaterally. Middle latency response showed normal compo-nent Po on the right ear and it was absent on the left. The component Pa was not identified on both ears. He showed skill and reliance on lip reading two years after the onset of the complete deafness. Now he can speak fluently and communi-cate with lip reading and written language, although no improvement of the complete deafness being noticed.

We concluded that the cortical deafness of this unique case might be caused by complete transec-tion of the acoustic radiation and cell degeneration in the medial geniculate body with the putaminal hemorrhage on both sides and the auditory system might be dominant to the contralateral hemisphere.