Inside The Brains Of Super-Agers: What Do They Have In Common?
Mental decline and dementia don't have to be part of the extreme longevity equation. Researchers call some centenarians and supercentenarians "cognitive super-agers," and a surprising number of people 100 and older share this mental acuity.
What do these people do to both grow so old and stay so sharp?
Among other things, it turns out a majority of those who attain exceptional ages demonstrate extraordinary resilience in the face of stress, says Emily Rogalski, Ph.D., a super-aging expert at Northwestern University's Feinberg School of Medicine, who for a decade has been studying people aged 80 through the 100s.
"The super-agers' brains look indistinguishable from a group of healthy 50- to 60-year-olds. They really seem to be on a different trajectory," Rogalski says. Her latest work is evaluating super-agers' life stories to get a better idea of how they've handled stress, whether it has involved surviving a Nazi death camp, coping with the death of a child, or dealing with cancer.
She's noticed a theme emerge: "We all encounter stress and have the opportunity to react in different ways. One reaction can be to rise above, and it seems like these super-agers are particularly good at identifying the best in a situation and figuring out how to move on."
Adding an element of wonder to whatever cognitive super-agers have going on, they’re doing it despite the tangible changes that occur in our brains as we age.
A 90-year-old's brain typically weighs 1,100 to 1,200 grams—nearly 10% less than a 40-year-old's brain. That shrinkage we experience later in life primarily affects the prefrontal cortex and hippocampus as well as the cerebral cortex, a part of the brain used for complex thoughts.
But people who attain exceptional ages have been found to have a thicker cingulate cortex, a region believed to play an important role in attention, cognitive control, decision-making, and memory. Super-agers' cerebrums also have been shown to include many more corkscrew-shaped von Economo neurons, which are involved in rapid communication across the brain, and their brains just generally seem to handle the wear and tear of aging better.
What's responsible for this: genetics or lifestyle?
What's still not entirely clear: Are centenarians born with larger, stronger brains? Or are they somehow able to activate a response to aging that compensates for the brain degradation others experience over time?
A new study of 340 healthy Dutch centenarians1 living independently finds they "experienced no decline in major cognitive measures, except for a slight loss in memory function" akin to what one might expect if they were in their 70s. Some of the studied centenarians, in fact, had brains that appeared very healthy, and they performed at a high level on cognitive tests. Others who died with no discernible degradation of their memories or their abilities to relate to others and solve problems had their brains examined, and here's where it gets wild: Their gray matter was as marred and scarred as that seen in people who die with advanced Alzheimer's, yet their brain function was never compromised. And the oldest of these folks was 108.
"Some individuals reach ages beyond 100 years and become centenarians with intact cognitive functions, which indicates that cognitive impairment is not inevitable at extreme ages," concludes the team at Vrije University in Amsterdam led by Henne Holstege.
How is that even possible? They're not sure. "It is still unclear to what extent individuals who maintain cognitive health until age 100 escape or delay decline," the researchers say, adding that 40% of us will develop dementia by the time we turn 100. If that sounds bleak, you can take comfort in this: 60% of us won't.
Once we're 100, though, the risk gets markedly higher. A person who lives to between 100 and 102 has the same chance of acquiring dementia as a person living to between 70 and 95. Put another way: 25 years of risk in that slightly younger population, Holstege's team says, is compressed into two years in centenarians. It also means that centenarians who never develop dementia should be considered that much more extraordinary.
And new work by an international team of researchers who scanned data collected from 101,457 brains ranging from a 16-week-old fetus to a 100-year-old is revealing that the brain adjusts as we age to help us meet the challenges of every stage of our lives.
"For those who are cognitively intact at about 100 or 101, they really seem stable for a significant period of time," says Tom Perls, who's been closely tracking the Dutch project. "It's as if they've demonstrated their ability to be resilient against a disease or even resistant against it. At that point, they just keep on going. They plateau. It's only when we start to see a decline in their cognitive function that we start to get worried."
Perls says the Dutch experience points up these realities about extreme old age: Debilitating brain disease is nowhere near as inevitable as it once seemed, and many super-agers appear to be resistant, resilient, or both.
Excerpted from The Big 100: The New World of Super-Aging by William J. Kole, available wherever books are sold. Copyright © 2023 William J. Kole. Printed with permission of the publisher, Diversion Books. All rights reserved.