Agraphia and micrographia: clinical manifestations of motor programming and performance disorders.

Rigorous studies involving cases of acquired language and memory disorders have contributed substantive information regarding higher cortical functions. Acquired disorders of handwriting, however, have remained a largely untapped resource which could be of great value to students of motor control. In this study, we demonstrate how two such disorders provide specific information regarding the motor control of handwriting. In a case of acquired agraphia due to a cerebrovascular accident there was a problem in programming the proper letter strokes and achieving the correct spatial location of strokes. In contrast, Parkinsonian patients with micrographia produced the appropriate letter strokes but could not maintain adequate force to preserve letter size. It appears that such information will help to dissect the handwriting skill into a number of functionally and anatomically separable subcomponents.