Researchers may have uncovered a key reason some people remain sharp as a tack into their 80s and 90s: Their brains resist the buildup of certain proteins that mark Alzheimer’s disease.
The study focused on what scientists have dubbed “super agers” — a select group of older folks who have the memory performance of people decades younger.
Compared with older people who had average brain power, super agers showed far less evidence of “tau tangles” in their brains, the researchers found.
Tau is a protein that, in healthy brain cells, helps stabilize the internal structure. But abnormal versions of tau — ones that cling to other tau proteins — can develop as well.
In people with Alzheimer’s, the brain is marked by a large accumulation of those tau tangles, as well as “plaques,” which are clumps of another protein called amyloid.
For years, amyloid plaques have gotten most of the attention as a potential target for Alzheimer’s treatment, said researcher Tamar Gefen, who led the new study.
But a body of evidence tells a different story: It’s the buildup of tau — not amyloid — that correlates with a decline in memory and thinking skills, said Gefen, an assistant professor at Northwestern University Feinberg School of Medicine, in Chicago.
These latest findings on super agers, she said, are in line with that research.
It’s not clear how many super agers are out there. One reason is that there’s no single definition of the term, said Claire Sexton, director of scientific programs and initiatives at the Alzheimer’s Association.
This study involved people aged 80 and older. But other research, Sexton said, has narrowed the focus to unusually sharp 90-somethings, or even centenarians.
The million-dollar question is: What does it take to be a member of this elite group?
It’s likely super agers have genetics to thank, in part, according to Sexton.
But in all probability, she said, it’s a mix of good genes, lifestyle factors and exposures over a lifetime, from physical activity, to social engagement, to mentally stimulating experiences.
In fact, previous research at Northwestern has shown those are common habits of super agers.
Gefen and her colleagues have also found brain differences between super agers and their peers with typical brain power: For example, super agers have more tissue volume in a brain region involved in processes like motivation and decision-making. Super agers also show a greater density of cells called Von Economo neurons, which are linked to social intelligence.