You can get Alzheimer’s disease in your brain (e.g., plaque and tangle build up) but you won’t necessarily get dementia. This is because of something called cognitive reserve. Everyone has it to some degree and you build it over your lifetime. But how exactly can it offset dementia? A review article by Scarmeas and Stern (2004) talks about possible mechanisms of different types of cognitive reserve.
Cognitive reserve is a construct, which means, just like intelligence or anxiety, we can’t directly measure it. We need to find something that can be directly measured to represent cognitive reserve. Evidence suggests that people have better outcomes if they are regularly intellectually, physically, and socially active. Thus, cognitive reserve is often represented by measures such as occupational status, years of education, and/or amount of physical, social, or mental activity.
Occupational attainment could compare people who worked in managerial roles versus office or trade workers. In this case, some might think the higher you climb the work ladder, the more cognitive reserve one must have. It seems that jobs that are complex enough to keep you mentally stimulated are protective against dementia. While this could make sense in isolation, occupational attainment alone is not sufficient to explain the complexities of cognitive reserve. It assumes that everyone can choose our job and be whatever we want to be. While occupation is a significant aspect of one’s adult life, it is not the only aspect.
Education is usually how many years you spent getting a formal education. Someone who completed high school, you’d have about 12 years of education. Someone who completed a postgraduate masters would have about 17 years of education. The assumption is that 17 years of education indicates higher cognitive reserve than 12 years of education. Education does have a role in later life outcomes, but it doesn’t capture everything. By this definition, the start of your life and is important for later life outcomes. But this is not true. Evidence has shown that even the adult brain continues to grow and change as you learn.
Cognitive reserve and dementia
Cognitive reserve can lower your chances of developing dementia. So, how can we get more of it? Stay physically, mentally, and socially active to help build cognitive reserve and slow cognitive decline (Clare et al., 2017).
- Clare, L., Wu, Y. T., Teale, J. C., MacLeod, C., Matthews, F., Brayne, C., & Woods, B. (2017). Potentially modifiable lifestyle factors, cognitive reserve, and cognitive function in later life: A cross-sectional study. PLoS Medicine, 14(3), 1–14. https://doi.org/10.1371/journal.pmed.1002259
- Scarmeas, N., & Stern, Y. (2004). Cognitive reserve: Implications for diagnosis and prevention of Alzheimer’s disease. Current Neurology and Neuroscience Reports, 4(5), 374–380. https://doi.org/10.1007/s11910-004-0084-7