Some people in their 80s are still matching the memory of people decades younger, and researchers say their brains may help explain why.

For more than 25 years, researchers at Northwestern Medicine have studied adults aged 80 and older known as “SuperAgers” to understand how some people keep exceptional mental sharpness late in life. These participants consistently perform on memory tests at levels similar to people at least 30 years younger, challenging the idea that cognitive decline is unavoidable with age.

Researchers said SuperAgers often share some lifestyle and personality traits, including being highly social and outgoing. But the strongest findings have come from their brains.

“It’s really what we’ve found in their brains that’s been so earth-shattering for us,” said Dr. Sandra Weintraub, a professor of psychiatry and behavioral sciences and neurology at Northwestern University Feinberg School of Medicine.

Weintraub is the corresponding author of a new paper summarising the results, published as a perspective article in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. The article is part of a special issue marking the 40th anniversary of the National Institute on Aging’s Alzheimer’s Disease Centers Program and the 25th anniversary of the National Alzheimer Coordinating Center.

The term “SuperAger” was introduced by Dr. M. Marsel Mesulam, who founded the Mesulam Center for Cognitive Neurology and Alzheimer’s Disease at Northwestern in the late 1990s. Since 2000, 290 participants have taken part in the program, and researchers have studied 77 donated SuperAger brains after death.

Some of those brains showed amyloid and tau proteins, also known as plaques and tangles, which are strongly linked to Alzheimer’s disease. Others showed no signs of those proteins.

“What we realized is there are two mechanisms that lead someone to become a SuperAger,” Weintraub said. “One is resistance: they don’t make the plaques and tangles. Two is resilience: they make them, but they don’t do anything to their brains.”

Researchers said SuperAgers score at least 9 out of 15 on delayed word recall tests, which matches the performance of people in their 50s and 60s. Their brains also show little to no thinning of the cortex, the brain’s outer layer. In some cases, a region called the anterior cingulate cortex is even thicker than in younger adults.

Scientists also found that SuperAgers have a higher number of von economo neurons, which are linked to social behaviour, as well as larger entorhinal neurons, which play a critical role in memory.

At the Mesulam Center, participants are evaluated each year and can choose to donate their brains for scientific study after death. Researchers said those donations have supported many of the program’s most important findings.

“Many of the findings from this paper stem from the examination of brain specimens of generous, dedicated SuperAgers who were followed for decades,” said co-author Dr. Tamar Gefen, associate professor of psychiatry and behavioral sciences at Feinberg, director of Feinberg’s Laboratory for Translational Neuropsychology and a neuropsychologist at the Mesulam Center.

“I am constantly amazed by how brain donation can enable discovery long after death, offering a kind of scientific immortality.”

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