Nearly 15 percent of people age 70 and older experience some form of dementia; that number jumps to nearly 35 percent for people over age 90. And yet other people live more than 100 years with sharp minds.
What helps some people protect their brain health well into the later years of life? That’s the question researchers from the Netherlands asked in a new, longitudinal study published in JAMA Network Open that examines mentally sharp 100-year-olds.
The researchers recruited 330 centenarians whom caregivers confirmed were mentally sharp. The participants underwent extensive testing of their cognition, memory, decision-making skills, verbal and special skills, attention and processing speed. The researchers combined these data with participants’ sex, age, education, vision and hearing capabilities, and physical health indicators. They followed them for as long as they could—until death or until they were no longer able to participate in the study.
They found surprising results. Study participants experienced no major declines in cognitive function except for slight losses in short-term memory. Most maintained their abilities to make decisions, come up with lists of words, recreate a drawing they had looked at, and avoid distraction.
After their deaths, forty-four of the participants underwent autopsies to measure the plaques, or tangles of protein, in their brains that are typical markers of Alzheimer’s disease. Although many participants had the brain plaques typical of people who develop Alzheimer’s disease, none of them showed signs of disease itself. In addition, participants with the genes linked to an elevated risk of developing Alzheimer’s disease showed no signs of cognitive decline.
While the study wasn’t able to draw firm conclusions about why the centenarians were able to maintain their cognitive abilities, the results show that participants were either able to resist neurological decline or what they call “cognitively resilient,” meaning they were exposed to the risk factors for cognitive decline but somehow avoided the disease.
The researchers did find some common attributes of the centenarians. Most attained a high level of education. On average, they finished high school and attained some advanced training or college education. More than half lived independently.
The majority of participants had good vision and hearing capacities. This is important because when older adults lose their ability to see and hear, they lose social connections and their ability to process information, which in turn can lead to cognitive decline.
And most of the participants had lived relatively physically active lives; more than 75 percent were still able to walk independently at the start of the study.
The take-home message: There are no firm conclusions about how to keep a sharp mind, but these centenarians give us some clues about how to maintain cognitive functioning: by staying physically active, attaining a high level of education, and optimizing our abilities to hear and see. Most importantly, they show us that it is possible to avoid neurological aging and maintain a sharp mind later in life.
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