Abstract
A 83-year-old right handed woman developed selective kana agraphia. She showed no neurological sign other than dysarthria and dysphagia. Although dysarthria was striking, auditory comprehension, reading comprehension, naming objects, intellectual and behavioral abilities were well preserved. Brain MRI and SPECT studies could not detect the specific lesions. The clinical course and negative EMG study led us to her diagnosis of progressive aphemia syndrome. The most conspicuous sign of her writing disturbances was characterized by omitting kana letters. We performed some deep test about writing process of kana words to clarify what stage her writing disturbances occurred. It may be reasonably assumed that there are three levels of processing in writing kana : moraic segmentation level, the moraic identification level and the sound-kana correspondence level. She had no problems with the first level and third level.
When asked to point out where a specific mora was among a word, she always pointed out the position forward to the correct one. We thought this disturbance is closely related to her actual writing disturbances with omission of kana letters. We concluded that she omitted the kana letters because the frame of the kana word decreased between the moraic segmentation level and the moraic identification level.
