The term cognitive reserve describes the mind’s resistance to damage of the brain. The mind’s resilience is evaluated behaviorally, whereas the neuropathological damage is evaluated histologically, although damage may be estimated using blood-based markers and imaging methods.
There are two models that can be used when exploring the concept of “reserve”: brain reserve and cognitive reserve. These terms, albeit often used interchangeably in the literature, provide a useful way of discussing the models.
Brain reserve, which refers to actual differences in the brain itself that may increase tolerance of pathology. Cognitive reserve refers to individual differences in how tasks are performed that may allow some people to be more resilient than others.
Using a computer analogy brain reserve can be seen as hardware and cognitive reserve as software. All these factors are currently believed to contribute to global reserve. Cognitive reserve is commonly used to refer to both brain and cognitive reserves in the literature.
You can think of cognitive reserve as your brain’s ability to improvise and find alternate ways of getting a job done. Just like a powerful car that enables you to engage another gear and suddenly accelerate to avoid an obstacle, your brain can change the way it operates and thus make added recourses available to cope with challenges. Cognitive reserve is developed by a lifetime of education and curiosity to help your brain better cope with any failures or declines it faces.
In 1988 a study published in Annals of Neurology reporting findings from post-mortem examinations on 137 elderly persons unexpectedly revealed that there was a discrepancy between the degree of Alzheimer’s disease neuropathology and the clinical manifestations of the disease. This is to say that some participants whose brains had extensive Alzheimer’s disease pathology, clinically had no or very little manifestations of the disease. Furthermore, the study showed that these persons had higher brain weights and greater number of neurons as compared to age-matched controls. The investigators speculated with two possible explanations for this phenomenon: these people may have had incipient Alzheimer’s disease but somehow avoided the loss of large numbers of neurons, or alternatively, started with larger brains and more neurons and thus might be said to have had a greater “reserve”.
Epidemiologic studies suggest that lifetime exposures including educational and occupational attainment, and leisure activities in late life, can increase this reserve.