痙性両麻痺児の視覚認知障害とその病巣について

DISTURBANCES OF VISUAL PERCEPTION AND THE LESIONS ON SPASTIC DIPLEGIA

　脳性麻痺の痙直型両麻痺児（SD児）12名を対象に，視覚認知障害の特徴とその発生機序について検討した。視覚認知障害は，Frostig視知覚発達検査を行い，視知覚指数と知能指数との比較で検討した。また，全例に頭部MRI検査を実施し，病巣を検討した。その結果，SD児の視知覚指数は知能指数よりも有意に低く（P＜0.05t検定），下位項目では「図形と素地」の項目がもっとも劣っていた。頭部MRI検査では，12例中10例で明らかな病巣が認められた。病巣は，両側側脳室体部の周囲白質を中心に，半卵円中心から頭頂葉，後頭葉の皮質下白質まで及んでおり，垂直後頭束，上縦束も障害されていると考えられた。視覚情報処理過程において，垂直後頭束は後頭葉と頭頂葉を，上縦束は頭頂葉と前頭葉をつなぐ重要な連絡線維であることから，SD児の視覚認知障害はこれらの連絡路障害に基づく器質的な症状であり，高次視覚認知の離断症状であると考えられた。

In a study of 12 cerebral palsy with spastic di-plegia, the relationship between their disturbances of visual perception and their lesions was discus-sed. All of them were performed Frostig Deve-lopmental Test of Visual perception and Tanaka-Binet Intelligence Test. Six of them showed dis-turbances of visual perception on Frostig Test. Subtest II, figure-ground, was the lowest of all subtests. The mean of perceptual quotient was under that of intelligence quotient significantly (p＜0. 05 t-test). MRI examination was performed to all and the lesions were detected at 10 of them. Six who showed disturbances of visual perception had the lesions and two who showed good visual perception had no lesions. The lesions were per-iventricular white matter and extended to semioval center and subcortical white matter at parietal and occipital lobes. Anatomically, their lesions correspond to superior longitudinal bundle and vertical occipital bundle and their bundles have important functions as the pass way of visual perception. Therefore, it was suggested that the disturbances of visual perception detected at spastic diplegia were based on the lesions and the mechanism was disconnection of higher visual class way.