伝導失語を呈した原発性進行性失語の1例

A case of primary progressive aphasia that presented conduction aphasia without dementia

　原発性進行性失語(primary progressive aphasia：以下，PPA)を発症し，診断後2年間経過観察した症例を経験した．家事や車の運転は可能で，認知症は認めず，失語以外に特に問題を認めなかった．失語症状としては，音韻性の錯語と錯書，および聴覚的言語把持力の低下を認め，伝導失語を呈していた．SPECTでは，左縁上回から左上側頭回の比較的限局した血流低下を認めた．2年の経過で失語症状の悪化および血流低下部位の広がりを認めたが，失語型は維持されていた．野菜の販売店に勤務しているが，可能な範囲で仕事も継続可能であった．

　PPAのような進行性疾患の場合，病状の進行により，のちに他の高次脳機能障害や認知症を発症することもあるが，本症例のように知的に保たれ比較的状態のよい場合は，言語聴覚士(以下，ST)のような専門職の助言・指導により社会活動を継続できる可能性がある．症例を取り巻く周囲の人への指導も重要であり，PPA症例のQOLの維持にSTなどの介入は重要な要素であると思われた．

　We report a case of primary progressive aphasia (PPA), who presented conduction aphasia consistently for two years.　She had neither dementia nor other neurological deficits except for aphasia.　She showed phonological paraphasia, paragraphia, and reduced short-term auditory verbal memory, which supported the diagnosis of conduction aphasia.　An MRI scan showed localized cortical atrophy of the left temporal lobe and SPECT revealed a reduction of the regional blood flow at the left supramarginal gyrus and superior temporal gyrus.　Although the severity of her aphasia and the size of affected region increased during the follow-up period of two years, the type of aphasia did not change and symptoms of dementia were not observed.　She is still independent in her daily life.　Whereas careful observation is necessary, as memory or other higher brain functions may deteriorate in the future, adequate advice and guidance by trained professionals such as speech-language-hearing therapists is useful for preserving social activities in some PPA patients, as in the present case.　Guidance of the people surrounding PPA patients is also important for maintaining the level of their quality of life (QOL).