Frontal lobe tasks do not reflect frontal lobe function in patients with probable Alzheimer's disease

Thirty-one patients with probable Alzheimer's disease (AD) according to NINCDS-ADRDA criteria were psychometrically tested with various frontal lobe tasks. The results were correlated with regional cerebral glucose metabolism (rCMRG1) as measured by positron emission tomography of 18F-2-fluoro-2-deoxy-D-glucose. RCMRG1 of frontal functional-anatomically defined regions was not linked to the performance seen in frontal lobe testing. The majority of the frontal lobe tasks showed a high correlation to severity of dementia that was related to rCMRG1 of the temporo-parietal cortex. There were high intercorrelations of frontal lobe test scores to other tests. Thus, these tasks seem to measure nonspecific cognitive changes in AD patients.