進行性非流暢性失語を呈する脳変性疾患の2例

Two Cases of Primary Progressive Non-fluent Aphasia

　進行性非流暢性失語が前景に立ち約5年から7年を経過した2症例を報告した。1例の失語像は，独特の音の歪みを伴う非定型的な超皮質性運動失語から無言状態へ移行した。両側第1前頭回，左第2前頭回，左帯状回前部，左前頭葉弁蓋部の著明な葉性萎縮と左側頭葉の一部の萎縮という画像所見より前頭葉優位型Pick病と考えられた。また，これらの部位の血流低下が認められた。他の1例は，言語症状が減弱型反響言語を伴う非定型的Broca失語から次第に反響言語や保続が著明となったことに加え，緩徐進行性の右不全麻痺を呈したことが特徴であった。画像所見では，左弁蓋部の軽度の萎縮と同部位の血流低下，左半球の広汎な糖代謝低下を認めた。失語像からみた場合，脳変性疾患による進行性失語は，しばしば古典的失語類型には分類し難い非定型失語像を呈することを指摘し，これらの変性失語においても初期より非流暢性失語像を示すことがあることを強調した。

Two patients were described with a five to seven -year history of primary progressive non-fluent aphasia. One patient developed atypical transcor-tical motor aphasia with marked anarthria, which has led to mutism. Magnetic resonance (MR) imag-ing showed lobar atrophy of the frontal lobe ac-centuated in the bilateral superior frontal gyri, the left middle frontal gyrus, the left anterior cingulate gyrus and the left operculum with some extension into the left temporal lobe. Single photon emission computed tomography (SPECT) scans demonstrat-ed a decrease of regional cerebral blood flow (rCBF) in the atrophic site. The patient was clinically and neuroradiologically diagnosed as hav-ing Pick's disease. Another patient presented with atypical Broca's aphasia, which has worsened with slowly progressive right hemiparesis. Mitigated, sometimes complete, echolalia was also observed. MR imaging and SPECT scans showed mild atro-phy and a decrease of rCBF in the left perisylvian region involving the frontal operculum, while a positron emission tomographic study disclosed diffuse hypometabolism in the left hemisphere. We pointed out that the features of primary progressive aphasia were frequently atypical in the light of clasical clasiffication of aphasia and that non-fluent aphasia might be observed even in the early stage of cortical degenerative processes.