Re-visiting Cognitive Reserve: The importance of multiple brain measures

The term “Cognitive Reserve” broadly refers to better-than-expected cognitive abilities in old age, presumed to reflect environmental/lifestyle factors earlier in life. This commentary addresses the question of what determines “better than expected” cognition. More specifically, it considers cognitive performance that is better than expected from standard clinical assessments of the brain. This is in the spirit of the original puzzle raised by (Katzman et al., 1988), who identified individuals whose cognitive abilities had been well above average despite post mortem revealing neuropathology associated with Alzheimer’s Disease. More commonly these days, the term is used by neurologists to describe people who show comparable atrophy on a clinical brain scan, yet differ markedly in their cognitive function. This “puzzle” is important, particularly if we can identify factors, such as lifestyle choices, that might boost this reserve, allowing individuals to maintain their cognitive abilities for longer, despite brain atrophy.