Learn how cognitive reserve can make some people more resistant to memory decline.
Andrew accompanied his father, Robert, to the memory clinic. Our evaluation found that Robert had a major neurocognitive disorder, probable Alzheimer’s disease, and that his memory and executive function were quite impaired. Andrew was not surprised when we made this diagnosis, but he was upset about his father and also asked about his own risk for dementia. He said, “My Uncle Walter is 85 and still makes rounds at the hospital every day. His patients say he is still as sharp as he ever was. But my father is only 76 and can’t remember how to drive to the grocery store! How can these brothers have aged so differently? Is there any way I can age like my uncle instead of like my dad?”*
*Andrew, Robert, and Walter are similar to many people seen in a Memory Disorder Clinic, but they are composite characters rather than individuals for the protection of privacy.
Why does memory decline differ so much between people of the same age, even those who are closely related?
Some brains appear to be stronger and more resilient in the face of aging or traumatic events. Cognitive reserve is an important idea that sheds some light on this mystery.
Today, Alzheimer’s disease is increasingly defined by biological markers, such as amyloid-beta and tau changes seen in blood tests or brain scans, rather than symptoms alone. This means the disease can sometimes be detected years before memory loss begins and also helps explain why some people may show significant disease changes without outward impairment.
The main idea of cognitive reserve is that some brains function more successfully than others despite similar degrees of destruction or degeneration, and that this is due to innate and acquired brain characteristics.
At birth, our brains already differ. Some are larger, some smaller. Some have greater specific or general intellectual potential. However, lifetime experiences, education, occupation, nutrition, and medical health all exert game-changing influences throughout our lives.
These differences are believed to reflect the quality of the brain’s internal connections and health. A healthy, well-developed, and well-nourished brain, combined with a medically healthy body, works more efficiently. It also resists the effects of injury from trauma or stroke, or compromise associated with diseases such as diabetes, high blood pressure, or depression.
Social engagement, lifelong learning, and even the use of technology are now also recognized as key contributors to building reserve.
An Alzheimer’s Disease Research-funded study led by Henne Holstege, PhD, provides a striking example of cognitive reserve in action. Her 100-Plus Study follows centenarians (people who are 100 years old or older) who remain cognitively sharp, even as their brains show signs of amyloid buildup or other age-related changes. Some centenarians carry protective gene variants that support immune responses and help clear toxic proteins, while others appear able to compensate for brain changes through still-unknown resilience pathways.
Together, these findings show that memory decline is not inevitable, and that some people can maintain healthy brain function for over a century despite Alzheimer’s-like pathology.
During childhood, a cognitively stimulating environment promotes the development of larger brain volume. Physical exercise and cognitive stimulation increase molecules that enhance the brain’s ability to change continuously throughout an individual’s lifetime.
A healthy brain in a stimulating environment strengthens existing connections and remodels its networks throughout life, supporting what is known as brain plasticity.
The combined effects of intellectual endowment, education, experience, and occupation appear to be significant influences on how a damaged brain compensates and preserves functioning. The decline in memory, executive function, and language skills associated with normal aging is slower in people with greater literacy.
Research shows that up to 45% of dementia cases could be prevented by addressing all of the following 14 modifiable risk factors throughout childhood, midlife, and late life. These risk factors include:
Social isolation, depression, poor sleep, and inactivity are now known to increase risk independently. Lifestyle approaches that target multiple factors simultaneously, such as trials like the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment (FINGER), provide the strongest evidence for prevention.
Get the latest news from the U.S. follow-up study to FINGER, called U.S. POINTER.
What advice was there for Andrew as he looked ahead to his later years? One of the most important things about the theory of cognitive reserve is that it gives us hope for fighting the effects of brain aging and degenerative disorders, even though we have not yet been able to discover medications that cure dementia.
Several new biologic therapies can now modestly slow Alzheimer’s progression in some people, but prevention and lifestyle approaches remain the most powerful tools for protecting brain health.
Early education, cognitive stimulation, and physical activity set the stage for later brain health. During adulthood, continued learning and engagement in challenging leisure-time activities can strengthen resistance to cognitive decline.
Large multidomain prevention trials also show the greatest benefit when diet, exercise, cognitive training, and cardiovascular risk management are combined.
Brain health is further supported by physical activity and good self-care, which includes adequate sleep, stress reduction, a balanced diet, and regular medical check-ups.
Individual genetic factors that affect the risk of dementia are currently unmodifiable. Still, the progression and expression of brain aging and disease are significantly influenced by how we live and how we utilize our brains. Andrew, being young enough to engage in physical and cognitive activities, is in a position to improve his long-term cognitive health outlook in later years.
As we learned more about Andrew’s family, it became clear that Walter and Robert had lived very different lifestyles. Walter attended college and graduate school and was a successful medical specialist who enjoyed engaging in cognitively challenging hobbies and pursuing lifelong learning.
Robert had finished high school but left college during his freshman year to support his aging parents in their family business. He was a hard worker, a good provider for his family, and a beloved man in his community. But he habitually neglected his physical health and leisure activities.
As he aged, his lifestyle became more sedentary, and he preferred to use his limited free time for relaxation rather than cognitive stimulation or physical exercise. He developed several chronic medical disorders, high blood pressure, and diabetes, and his attention to their management was not a priority.
This may have accounted in part for the brothers’ very different experiences in aging. Beyond whatever differences were due to genetics, Walter seems to have developed a greater level of cognitive reserve. Walter exercised his mind and body and cared for his medical health more consistently than Robert did. This lifestyle difference may partly explain why Walter’s mind continued to function at a high level while Robert’s was declining.
BrightFocus Foundation is a premier global nonprofit funder of research to defeat Alzheimer’s, macular degeneration, and glaucoma. Since its inception more than 50 years ago, BrightFocus and its flagship research programs—Alzheimer’s Disease Research, Macular Degeneration Research, and National Glaucoma Research—has awarded more than $300 million in research grants to scientists around the world, catalyzing thousands of scientific breakthroughs, life-enhancing treatments, and diagnostic tools. We also share the latest research findings, expert information, and resources to empower the millions impacted by these devastating diseases. Learn more at brightfocus.org.
Disclaimer: The information provided here is a public service of BrightFocus Foundation and is not intended to constitute medical advice. Please consult your physician for personalized medical, dietary, and/or exercise advice. Any medications or supplements should only be taken under medical supervision. BrightFocus Foundation does not endorse any medical products or therapies.
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