Fluoro-Deoxy-Glucose Positron Emission Tomography Correlates of Impaired Activities of Daily Living in Dementia With Lewy Bodies: Implications for Cognitive Reserve

Objectives: 1) To investigate the neural substrate of impaired activities of daily living (ADL) in dementia with Lewy bodies (DLB) and 2) to explore, in the context of cognitive reserve, if hypometabolism was more pronounced in well-educated patients at the same level of every day impairment Methods: Twenty-one patients with DLB underwent an extensive clinical evaluation including cerebral positron emission tomography with F-18-fluoro-2-deoxy-glucose scanning. First, brain areas were identified, where ADL performance and glucose metabolism were significantly correlated, controlling for individual differences in cognitive and motor dysfunction. Second, it was tested, if there was a significant negative association between metabolism and years of education in brain regions associated with ADL performance. Again, a correction for cognitive and motor impairment was deployed. Results: There was a significant association between glucose hypometabolism and impaired ADL performance in an extensive bra in cluster located in the tight temporoparietal cortex. furthermore, schooling and metabolic rate were inversely associated in the right Brodmann area 19, controlling for ADL performance. Conclusions: The study suggests that 1) certain brain metabolic alterations are specifically associated with the loss of everyday competence, even if differences in cognition and motor function are taken into consideration and 2) well-educated patients can offset more brain damage until reaching the same degree of ADL impairment as their less educated counterparts. These results extend the literature on cognitive reserve to a region-specific effect on ADL performance (Am J Geriatr Psychiatry 2009; 17:188-195)