Why do some 80-year-olds have exceptional memories and outstanding critical thinking skills? How do certain 90-year-olds maintain robust social lives?
These are the questions researchers at Northwestern University have been trying to answer for the past 25 years.
Their new study, published in the medical journal Alzheimer’s & Dementia, reveals that there are distinct biological and behavioral traits that keep superagers—people 80 and up with the cognitive skills of those 20 to 30 years younger—so spry.
Superagers tend to be social, outgoing, and independent. Perhaps most astounding is how youthful their brains appeared in both neuroimaging and neuropathology tests.
“They defy the normal trajectories of aging,” said study author Tamar Gefen, PhD, an associate professor of psychiatry and behavioral sciences at Northwestern’s Feinberg School of Medicine, as well as a neuropsychologist at the Mesulam Center for Cognitive Neurology and Alzheimer’s Disease.
Northwestern’s research into superagers kicked off in 2000 as part of a quest to help scientists identify factors that might protect against neurodegenerative diseases like Alzheimer’s.
Since then, the research team has investigated the behaviors and habits of 290 superagers and studied 77 brains donated to the Mesulam Center. Participants were evaluated annually and had the option to donate their brains for post-mortem evaluation. They also underwent bloodwork, received MRIs, and shared their medical histories. “They give us everything,” Gefen told Health.
Who exactly qualified as a superager for the research? Someone aged 80 or older who scored within the average range on various cognitive tests and who could remember at least nine out of 15 words on a verbal learning test—a performance that’s typically seen in people aged 56 to 66.
Memory was the key marker because it’s the cognitive skill that declines the most during aging. “Superagers are defined by their outstanding memory capacity,” Gefen said.
You might assume that superagers are universally healthy, but the researchers found they had drastically different lifestyles. For example, some were physically active and ate healthy diets. Others smoked, regularly drank alcohol, barely exercised, and slept poorly night after night.
One trait that did stick out was how sociable the superagers were compared to their neurotypical peers—the control group recruited for the research. Superagers consistently rated social interactions and relationships more positively and tended to be more extroverted.
They also appeared to prioritize their autonomy. Superagers lived independently, and made their own decisions about their lives, diets, and relationships. Gefen suspects autonomy has been overlooked as a component of healthy aging.
The researchers also conducted neuroimaging and neuropathology tests to see if the brains of superagers looked different than those of their neurotypical peers—and found several notable differences.
Typically, as you age, the cerebral cortex—the brain’s outermost layer responsible for memory, thinking, problem solving, and reasoning—thins out. That thinning can lead to cognitive deterioration, research shows. But in superagers, the cortex showed minimal signs of cortical thinning and aged much more slowly compared to their neurotypical peers.
Cortical thickness was especially greater in the anterior cingulate cortex, a region involved with emotions, decision-making, motivation, and, perhaps most notably, social behavior—all skills the researchers said were particularly pronounced in superagers.
Another significant finding: the large number of von Economo neurons—cells linked to social behavior—in superager brains. “They were packed in there like sardines. Tons and tons of neurons,” Gefen said.
Also striking, Gefen said, was that entorhinal neurons, located in the hippocampus and related to memory, were much larger, plumper, and healthier than those of their same-aged peers and even 50-year-olds.
Superager brains also seemed to cope better with neurofibrillary tangles—abnormal clumps of protein, like tau, that are hallmarks of Alzheimer’s disease. Plaques and tangles attack the hippocampus, the part of the brain responsible for memory, Gefen said. But in superagers, either the tangles developed more slowly or the brain appeared more resilient against their effects.
That’s interesting and encouraging, Cari Levy, MD, PhD, a professor of geriatric medicine at the University of Colorado’s Anschutz Medical Campus, told Health. It suggests the accumulation of amyloid and tau proteins doesn’t always lead to dementia.
Finally, superagers had fewer microglia, cells that attack disease in the brain, compared to both their peers and 50-year-olds. According to Gefen, this could point to a unique immune response that helps keep superagers cognitively sharp.
The hope, according to Levy, is that this research could lead to a better understanding of how to create resilience in people who are prone to developing plaques.
As for what individuals can take from the findings, there isn’t anything concrete to grasp onto—these individuals may simply be born with genetic advantages that protect their brain health, Gefen said.
Still, a bulk of research suggests that certain lifestyle habits may help reduce the risk of age-related diseases. Levy recommends:
- Aiming to get some physical activity daily
- Eating a high-quality, plant-based diet
- Avoiding smoking
- Sleeping seven to eight hours each night
Keeping your brain active is also key, Levy said. Hobbies like quilting, photography, music, theater, dance, or creative writing can help. So can maintaining close relationships and finding a sense of purpose, whether through volunteering or caring for a loved one.
