A case of pure agraphia due to left thalamic hemorrhage.

Pure agraphia is an isolated writing disturbance without intellectual impairment, aphasia, alexia, or apraxia. The authors report a case of pure agraphia following left thalamic hemorrhage. The patient showed impairment in the writing of both kanji and kana. The most frequent error in the writing of kanji was substitution (46%) followed by no reaction (23%) and partial omission or addition of characters (21%). The copying of kanji by hand was normal. Even when the patient was unable to write a kanji character, he understood the meaning and correctly recited the other readings. He complained that he could not recall the graphic image of the kanji. When we cued the patient by writing a part of a kanji he initially failed to recall, he correctly completed the character. The kanji and kana he was unable to write were inconsistent over time: in some cases he was unable to write words he had successfully written a week before, and vice versa. These findings suggested that the patient's pure agraphia resulted from combined impairments in recalling and selecting letters. While the thalamic lesion might have influenced the manifestation of pure agraphia, the dysfunction seemed to originate from the secondary negative effect of the lesion on the function of the left cerebral cortex.