The brain reserve hypothesis, brain atrophy and aging

Background: Researchers have used the concept of brain reserve to explain the dissociation between pathological brain damage and cognitive and functional performance. A variety of brain reserve hypotheses exist, and different empirical strategies have been employed to investigate these variants. Objective: The study investigates (i) the relationship between measures of brain burden (atrophy, white matter hyperintensities (WMH)) and measures of reserve (education, creativity, and intelligence); (ii) the relationship between cognitive decline and reserve; (iii) whether measures of reserve mediate the effect of atrophy on estimated cognitive change, and (iv) the association between brain risk factors, education and atrophy. Methods: A cross-sectional study of a sample of 446 individuals 60-64 years of age who underwent MRI scans as part of a large epidemiological study. Measures were taken of education, intelligence, creativity, cognitive speed, brain volume, WMH, estimated cognitive decline from earlier in life and brain atrophy. Results: No association was found between estimated cognitive decline and brain burden ( atrophy, WMH). Risk factors for brain insult were not associated with greater brain atrophy in the less well educated. Neither education, nor any other measure including intelligence or creativity, provided a buffer for cognitive decline in individuals with high levels of brain atrophy. Conclusion: Little support was found for the brain reserve hypothesis. Copyright (c) 2007 S. Karger AG, Basel.