A 56-year-old right-handed man with 10 years of schooling, who suddenly developed writing problems, is described. An M.R.I. revealed a left posterior cortico-subcortical parietal lesion. The patient was not aphasic, had no neglect, and no apraxia. In contrast, spontaneous writing, written naming, writing to dictation, and copying of words and sentences showed a remarkable impairment. Letters were ill-formed; nonletters, stroke and letter repetitions, and omissions were present, both in words and nonwords; some letter substitutions were also found. There were no effects of word length, imageability, frequency, or word class. Oral spelling was normal. All these features are typical of a peripheral dysgraphia. An inability to use abstract motor patterns as input to neuromuscular routines is suggested as the major deficit, with minor impairment to the allographic conversion system.
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