INFERIOR PARIETAL PERFUSION, LATERALIZATION, AND NEUROPSYCHOLOGICAL DYSFUNCTION IN ALZHEIMERS-DISEASE

The severity of inferior parietal perfusion deficits in Alzheimer's di sease (AD) is strongly associated with global intellectual decline. Th e relationship to specific losses of neuropsychological functioning, h owever, is less clear, as is the relative importance of the side (left vs. right) of hemispheric deficit. In this study, 53 patients with pr obable AD and 35 elderly controls received both a resting Xe-133 rCBF measurement and neuropsychological examination. AD patients demonstrat ed the expected bilateral deficits in inferior parietal perfusion, as well as impairment on measures of mental status, intelligence, verbal and visual memory, attention, language, and construction abilities. Th e severity of this bilateral parietal deficit, in turn, was associated with virtually all of these AD-related neuropsychological impairments , most strongly with declining Performance IQ. Left-sided deficits cor related better with overall declines in IQ, as well as with declining attention and language fluency. Right-sided deficits, on the other han d, correlated best with declines in mental status and-paradoxically-ve rbal memory and contributed independently to declines in Full Scale an d Performance IQ. In terms of the number and strength of their associa tion to neuropsychological measures, left-sided deficits appear much m ore predictive of cognitive decline in AD. Right-sided deficits, howev er, may be most important for predicting aspects of performance skill that are only indirectly assessed in standard paper-and-pencil format. Overall, it appears that both sides make significant, but independent contributions to general functional decline in AD, but that left-side d deficits are more closely associated with cognitive decline as measu red by most standard neuropsychological measures. (C) 1996 Academic Pr ess, Inc.