“Superagers” Keep Youthful Memories — but Their DNA Looks Ordinary

Some people in their 80s and 90s have the memory of someone decades younger. These superagers are a puzzle — and a new study rules out one tempting explanation: it is not simply that they inherited Alzheimer’s-resistant genes.

Researchers at the University of Chicago’s HAARC Center and the Translational Genomics Research Institute, writing in Alzheimer’s Research & Therapy, compared the DNA of 142 superagers with 89 cognitively average older adults across five sites in the US and Canada.

What a superager is

The term has a specific definition rather than a loose one: individuals aged 80 or above whose episodic memory performance matches that of people decades younger, typically those in their fifties and sixties.

That is a demanding criterion. Episodic memory — recall of specific events and information — declines measurably in most people from middle age onward, so matching a much younger average is not merely aging well but performing outside the expected range entirely.

Other cognitive domains are not part of the definition. Vocabulary and accumulated knowledge hold up well into old age generally, so a criterion based on them would identify almost nobody unusual.

What they found

Examining the APOE gene and three polygenic risk scores, the team found no genetic distinction between the superagers and their ordinary-memory peers.

Both measures were the right ones to check. APOE is the strongest common genetic factor in late-onset Alzheimer’s — one variant substantially raises risk, another lowers it — so an enrichment of the protective form among superagers would have been the obvious explanation.

Polygenic risk scores aggregate the small effects of many variants into a single figure, capturing genetic contribution that no individual gene reveals. Finding no difference on either means the absence is not merely a matter of looking at the wrong gene.

Why a negative result matters here

If genetics explained it, “identifying SuperAgers might be as simple as performing genetic testing rather than the comprehensive cognitive evaluations we currently use,” said Emily Rogalski, PhD.

That is the practical consequence. Studying superagers requires finding them, and doing so currently means extensive neuropsychological assessment of large numbers of older adults to identify a small proportion — expensive and slow.

A genetic marker would have made recruitment straightforward. It also would have made the phenomenon less interesting, since something determined at conception offers little to the rest of the population.

So what makes them special

Related work has found superagers possess super neurons — significantly larger cells in memory-related brain regions than typical older adults.

The relevant region is the entorhinal cortex, the gateway through which information passes to the hippocampus, and among the first areas affected in Alzheimer’s. Larger neurons there suggests the cells resist the shrinkage that normally accompanies aging.

Whether that is cause or consequence is unresolved. Larger neurons may make the memory performance possible, or sustained cognitive activity may maintain the cells — and postmortem tissue cannot distinguish them.

What follows

The upshot for the rest of us: exceptional cognitive aging may owe more to modifiable, biological factors than to the luck of the genetic draw.

That reading is reasonable and should be held loosely. Ruling out one class of explanation does not establish another, and non-genetic does not mean modifiable — developmental factors, early-life circumstances and events long past are non-genetic and equally unavailable to intervention now.

Two kinds of resilience

Research on exceptional cognitive aging distinguishes two possibilities that the superager literature has been working to separate.

One is resistance: the brain does not accumulate the pathology in the first place. Someone with minimal amyloid and tau at ninety has avoided the disease process rather than withstood it.

The other is resilience proper: the pathology accumulates and the person functions anyway. That is the more interesting case, because it implies something compensating rather than something absent.

Autopsy studies of superagers have found examples of both, and notably some individuals with substantial Alzheimer’s pathology who showed no impairment during life — which places them firmly in the second category.

The distinction matters for what could be done with the finding. A resistance mechanism suggests prevention: stop the pathology forming. A resilience mechanism suggests something quite different — that people already accumulating pathology, which is most older adults, might be helped to tolerate it. Given how poorly attempts to remove pathology have translated into cognitive benefit, the second target may be the more practical one.

What the finding does establish is where to look next, which is what a well-designed negative result is for. Research news, not medical advice.