右側頭後頭葉皮質下出血にて生じた健忘症候群

Amnestic Syndrome after Right Temporo-occipital Subcortical Hemorrhage

I．はじめに

　健忘を中核症状とする病態は健忘症候群と呼ばれ，遠隔記憶や瞬時記憶は保たれるが，記銘力障害のため近時記憶が選択的に障害されるといわれている．また健忘は痴呆性疾患の主要症候の1つでもあり，脳血管障害に伴うものの頻度が高い．しかし，学習記憶障害だけでなく，自分自身の生活史すら忘れるなどの生活記憶障害も認められることが特徴である^3）．

　脳血管障害に起因する健忘症候群の報告は数多く見受けられるが，大部分が脳梗塞症例であり，脳出血症例の報告はきわめて少ない．

A case of right temporo-occipital subcortical hemor-rhage with amnestic syndrome was reported. A 65-year-old woman presented with visual disturbance and headache. CT and MRI demonstrated a hemorrhagic le-sion in the right occipital lobe involving parahippocam-pal gyrus.

Neurological examination on admission revealed left homonymous hemianopsia and anterograde and retro-grade amnesia. Neuropsychological examination re-vealed marked recent memory disturbance, but she had visual retention and verbal retention, and her value in WAIS (Wechsler Adult Intelligence Scale) was normal.After 40 days, she was discharged without improve-ment of amnesia.

These findings suggest that the cortico-medial tem-poral lobe pathway was disturbed by subcortical hemorrhage, and we think there are connective fibers between visual and verbal memory systems. This is the first report of hippocampal amnesia fol-lowing temporo-occipital subcortical hemorrhage.