[A Japanese case of crossed aphasia in a right-handed patient. Apropos of kana and kanji].

要旨

The Japanese orthography has some unique characteristics. Two types of Japanese characters, kana (phonetic symbols) and kanji (semantic and phonetic symbols), are used in combination. Although kana has simple forms and a limited number of characters, and kanji has complex forms and an infinite number of characters, Japanese aphasic patients often have trouble using kana characters properly. In the present case of crossed aphasia of a right-handed Japanese man due to a large hypertensive intracerebral hematoma in the right side, we also observed the impairment in kana processing. He could neither speak nor read aloud, but on multiple choice examinations, he could point to pronounced kanji letters. Although he could point to pronounced kana words, he could not point to kana letters. We will review some tachistoscopic studies of recognition and comprehension of the lateralized visual informations of kana and kanji for normal Japanese and for Japanese patients with disconnection syndrome. And we will discuss the right (minor) hemispheric ability to recognize kanji letters and kana words, and we will also talk about the restricted capacity for transcallosal transference of the visual language informations.

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