Regional hypometabolism related to language disturbance in Alzheimer's disease.

To elucidate the nature of language disturbance in Alzheimer's disease (AD) and the cerebral area involved in it, we studied 65 AD patients with the Western Aphasia Battery (WAB) and with 18F-fluorodeoxyglucose and positron emission tomography. Partial correlations were evaluated between the Aphasia Quotient of WAB and regional cerebral glucose metabolism normalized by the mean metabolic rate in the bilateral primary sensorimotor areas after controlling age, sex, education and severity of illness. Language disturbance in AD is accounted for by deficits in the semantic processing of language and is related to glucose hypometabolism in the inferior temporal gyrus and inferior parietal lobule, especially in the dominant side. These results offer further evidence suggesting that the lexico-semantic processing system is mediated in these regions.