Cerebral metabolic relationships for selected brain regions in Alzheimer's, Huntington's, and Parkinson's diseases.

Local CMRGlc values were determined for 13 regions in each hemisphere from tomographs of patients with Alzheimer's, Huntington's, and Parkinson's diseases who were studied using [18F]fluorodeoxyglucose with positron emission computed tomography. Intercorrelations among the 26 regional measures were calculated for each disease state and for normal controls, and were accepted as reliable at p less than 0.01, uncorrected for the number of comparisons. The number of reliable correlations was found to be decreased in Parkinson's and Huntington's diseases, two primarily subcortical disorders, and increased in Alzheimer's disease, a primarily cortical disorder. The changes suggest that one role of the basal ganglia involves coordinating or pacing the ability of cortical brain regions to function as a unit.