An important concept that is crucial to the understanding of cognitive health is known as “cognitive reserve” (CR). You can think of cognitive reserve as your brain’s ability to improvise and find alternate ways of getting a job done. Your brain can change the way it operates and thus make added resources available to cope with challenges. Cognitive reserve is developed by a lifetime of education and curiosity, but it can also be stimulated late in life. 

The concept of cognitive reserve originated when researchers described individuals with no apparent symptoms of dementia who were nonetheless found at autopsy to have brain changes consistent with advanced Alzheimer’s disease. These individuals did not show symptoms of the disease while they were alive because they had a large enough cognitive reserve to offset the damage and continue to function as usual. 

Since then, research has shown that people with greater cognitive reserve are better able to stave off symptoms of degenerative brain changes associated with dementia or other brain diseases, such as Parkinson’s disease, multiple sclerosis, or a stroke. A more robust cognitive reserve can also help you function better for longer if you’re exposed to unexpected life events that demand extra effort from your brain.

The concept of reserve accounts for individual differences in susceptibility to age-related brain changes or Alzheimer’s disease-related pathology. There is evidence that some people can tolerate more of these changes than others and still maintain function. Epidemiologic studies suggest that lifetime exposures including educational and occupational attainment, and leisure activities in late life, can increase this reserve. Individuals with high reserve will not demonstrate disease-related clinical symptoms as early as individuals with low levels of reserve. Cognitive reserve refers to individual differences in how tasks are performed that may allow some people to be more resilient than others. For example, there is a reduced risk of developing Alzheimer’s disease in individuals with higher educational or occupational attainment.

Based on US census categories, participants were grouped into low (unskilled/semiskilled, skilled trade or craft, and clerical/office worker) and high (manager business/government and professional/technical) occupational levels. Those with low lifetime occupational attainment had 2 times greater risk of developing dementia than those with higher lifetime occupational attainment. 

The concept of cognitive reserve holds out the promise of interventions that could slow cognitive aging or reduce the risk of dementia. It has also been demonstrated to provide benefit in vascular injury, Parkinson’s disease, traumatic brain injury, HIV, neuropsychiatric disorders and multiple sclerosis. The concept of CR suggests that the brain actively attempts to cope with brain damage by using pre-existing cognitive processing approaches or by enlisting compensatory approaches. This would allow an individual with high CR to better cope with the brain damage than an individual with lower CR. In CR, brain function rather than brain size is the relevant variable. Thus the CR concept is an active form of reserve in that the same amount of brain damage or pathology will have different effects on different people. Disease pathology slowly develops over time independently of CR, and that the pathology begins many years before the onset of clinically diagnosed AD. Since people with greater reserve should be able to tolerate more AD pathology, the onset of clinical dementia should be delayed. 

The evidence suggests that experiences at all stages, even in late life, can impart such reserve. These findings support the possibility that it may be possible to intervene even later in life in order to increase CR, slow age-related cognitive decline, and prolonged healthy aging. The most successful remediation approach to date has been aerobic exercise. The aerobic exercise may in effect boost brain reserve, for example by improving plasticity. Cognitive intervention, such as through engagement with challenging games, may help increase CR by improving the efficiency of the cognitive networks underlying executive control. Data clearly suggest that aspects of life experience can impart reserve against age- or disease-related pathology. However, the exact “recipe” for helping to create this reserve is still unknown. A recommendation would be to maintain educational and mentally stimulating activities throughout life.

It is encouraging that we can make changes that improve our mental functioning independently of neurological disease progression. In other words, with enough cognitive reserve, we can continue to function normally even in the face of progressing Alzheimer’s disease. Our brain can adapt. This is one more reason to stay mentally and physically active—even late in life.