COGNITIVE CORRELATES OF REGIONAL CEREBRAL BLOOD-FLOW IN ALZHEIMERS-DISEASE

Objective.-To study the relationship between relative regional cerebral blood flow (rCBF) and performance on a variety of neuropsychological tests in a group of subjects with Alzheimer's disease. Design.-Analysis of the relationship between relative rCBF and neuropsychological performance using stepwise multiple regressions and Pearson Product-Moment Correlation coefficients. Setting.-University dementia clinic and research laboratory. Participants.-Twelve mildly demented patients with Alzheimer's disease (Mini-Mental State examination [MMSE] scores, 24 to 29; age, 56 to 78 years); 38 moderately demented patients with Alzheimer's disease (MMSE scores, 0 to 23; age, 59 to 86 years); and eight normal control subjects (MMSE scores, 27 to 30; age, 61 to 79 years). Main Outcome Measures.-Single photon emission computed tomography and the blood flow tracer N-isopropyl-p-iodoamphetamine iodine 123 were used to measure relative rCBF. Cognitive performance was assessed by grouping neuropsychological tests into clusters reflecting frontal lobe abilities, perseveration, memory, and visuoconstructive abilities. Results.-While MMSE score was a significant (P<.05) predictor of visuoconstruction, frontal lobe, and memory cluster scores, relative rCBF was a weaker predictor of neuropsychological performance, with only right orbitofrontal relative rCBF emerging as a significant (P<.05) predictor of the frontal cluster score and right parietal relative rCBF as a significant (P<.05) predictor of the visuoconstruction cluster score. Conclusions.-These results support our a priori grouping of neuropsychological tests into frontal and visuoconstruction clusters and suggest that these two clusters are good measures of frontal and parietal lobe function, respectively.