[Neuropsychological analysis in 2 cases of infarction in the left precentral gyrus--with special reference to apraxia of speech and agraphia].

It remains controversial whether agraphia can coexist in a case with apraxia of speech, and whether an apraxia of speech can be classified into a category of aphasia. We examined the presence of agraphia in 2 right-handed patients of apraxia of speech. Case 1 of mild agraphia showed an infarcted lesion in the left precentral gyrus extending to the neighboring white matter, which involving the arcuate fasciculus on MRI. Positron emission tomography (PET) indicated decrease of cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in the infarcted lesion, but no decrease of CBF and CMRO2 in the Broca's area. In this case, agraphia was more conspicuous in "kanji" than in "kana" and severity of the agraphia was not correlated to that of speech disturbance on naming test. Case 2 without agraphia showed a small infarcted lesion in the left precentral gyrus, which did not extend to the deep white matter on MRI. Agraphia can coexist with apraxia of speech in a case with the lesion in the left precentral gyrus, in which the cortical lesion is relatively widespread or extends to the deep white matter. However, lack of etiological connection between the agraphia and the apraxia of speech was suggested. We could not confirm the location in the left precentral gyrus which is responsible for the agraphia.