[Case of Moyamoya disease with agraphia caused by a frontal lesion].

A 45-year-old woman showed agraphia and decreasing spontaneity. She was diagnosed as Moyamoya disease by cerebral angiography. CT scans revealed the abnormal low density area in the left frontal lobe, and the regional cerebral blood flow study showed low perfusion in the bilateral frontal lobe and the left high convexity area. She could copy specimens of the author's writing, but her spontaneous writing and dictation were impaired with either hand. The form of each letter she wrote was not so distorted, but wrong letters were substituted for the correct ones. Errors in Kana-writing were more common than in Kanji. Although her spontaneous speech was diminished, auditory comprehension, reading and constructional abilities were unaffected. She exhibited no agnosia and apraxia. Agraphia in this case was caused by a disconnection between the visual image and auditory image and/or between the visual image and kinesthetic image. Inner speech (Luria, AR et al, 1968) in this case might be disturbed, and decreasing spontaneity and delay of response resulted from the frontal lesion. The writing process may be constituted of many factors; images of visual, auditory and kinesthetic as well as primary functions of sensory and motor. Furthermore, it may be necessary for normal writing that one's inner speech, activities and intention of writing behavior are intact.