[Incomplete Gerstmann syndrome with a cerebral infarct in the left middle frontal gyrus].

A 65-year-old right-handed man noted a sudden onset of numbness and weakness of the right hand. On the initial visit to our hospital, he showed severe acalculia, and transient agraphia (so called incomplete Gerstmann syndrome) and transcortical sensory aphasia. Brain MRI revealed a fresh infarct in the left middle frontal gyrus. The paragraphia and aphasia improved within 14 days after onset, but the acalculia persisted even at seven months after onset In an 123I-IMP SPECT study, the cerebral blood flow (CBF) was found to be decreased in the infarction lesion and its adjacent wide area, the ipsilateral angular and supramarginal gyri, and contralateral cerebellar hemisphere. We speculate that inactivation in the infarction lesion caused the CBF decrease in the non-infarcted areas due to diaschisis. This case indicates that Gerstmann syndrome can be caused by not only dysfunction of the angular gyrus but also of the left middle frontal gyrus in the dominant hemisphere.