[A case of agrammatism due to cerebral infarction of the middle-lower part of the right precentral gyrus].

A right-handed 75-year-old man was admitted to our hospital complaining of sudden speech difficulty. Neurological examination showed slight left facial palsy of central origin. Although his spontaneous speech was fluent and contained no phonological or verbal paraphasia, it was like telegraphic speech, omitting or misusing postpositional particles. There was no history of changing handedness or family history of sinistrality or ambidexterity. Brain magnetic resonance imaging revealed fresh infarction of the middle-lower part of the right precentral gyrus. The WAIS-R VIQ, PIQ, and total IQ scores were 108, 100, and 117, respectively. In the explanation of a four-frame comic strip of the SLTA, there were misuses of postpositional particles in both speaking and writing. There was about 10% misuse on 249 questions for inserting postpositional particles in sentences. He had difficulty in changing from active- to passive-voice sentences and vice versa. In this patient, the lesion of the middle-lower part of the right precentral gyrus might be important for the expression of agrammatism in crossed aphasia.