Abstract
We analyzed the processes of writing to dictation and copying letters with the use of VTR recordings of performances in two agraphic patients ; a patient with alexia with agraphia and a patient with pure agraphia.
The patient with alexia with agraphia due to an infarction that mainly involved the left angular gyrus wrote nothing when he could not make a correct response to dictation. However, his copying of letters was satisfactory and performed with normal sequences of strokes. The writing speed in copying was not different for the Kanji characters that the patient could or could not write to dictation. These findings suggest that the motor pattern for writing letters was preserved in this patient. Patients with alexia with agraphia may have difficulty in the recollection, selection, or both of letters to be written.
The patient with pure agraphia following an infarction in the left superior parietal lobule wrote letters without spatial distortion. His erroneous writings were characterized by partial lacking and incorrectness of the letters. The patient showed abnormal sequences of strokes and completed a stroke by piecing out several fragments. This abnormal motor pattern for writing was observed more frequently in writing the letters that could not be written to dictation than in the correct responses. Copying letters was better than writing to dictation, but it was also performed with the abnormal motor pattern. The writing speed in copying was slower for the Kanji characters that could not be written to dictation than for those written correctly. Copying requires no recollection or selection of letters to be written. We thus considered that the disordered motor pattern for writing may play a role in the pathogenesis of pure agraphia.
