“Super-Agers” Longevity Study: Why Some People Don’t Get Alzheimer’s

Age is the major risk factor for Alzheimer’s — approximately 10 percent of people over the age of 65 develop the disease. As cases are set to triple by 2050, scientists are racing to understand how they can stave it off. They’ve set their sight on a small group of older people who don’t experience any cognitive decline, called  super-agers. 

“Superagers” is a term first coined by scientists at Northwestern SuperAging Research Program to describe people in their 80s and 90s with superior cognitive abilities, memory, and an active social life. While it isn’t an “official” scientific term, it is very useful for researchers — allowing them to study what makes these individuals so healthy. 

One major question scientists are hoping super-agers can help them answer: What is it that protects some people from neurodegenerative diseases like Alzheimer’s?

A 2023 study published in the Journal of Alzheimer’s Disease performed an autopsy on the brains of 102 super-agers, aged 97 at the time of death. Testing done two to 12 months prior to their death confirmed the these nonagenarians were still cognitively sharp.  Despite many having the hallmark beta-aymloid plaques, the super-agers never never developed Alzheimer’s.

And in July of 2023, a Spanish study, one of the longest and largest of its kind, pinpointed a few more traits that may explain how these so-called super-agers retain their wit and memory.

“We are now closer to solving one of the biggest unanswered questions about superagers: whether they are truly resistant to age-related memory decline or they have coping mechanisms that help them overcome this decline better than their peers,” said lead author Marta Garo-Pascual, a neuroscience graduate student at the Queen Sofia Foundation Alzheimer Centre in Madrid.

1. Super-agers’ brains don’t gradually shrink as much as other people’s brains do 

The super-ager’s brain may be resilient to Alzheimer’s because it appears to shrink slower. In fact, one part of the brain might not shrink at all in this group of adults. 

Over six annual visits, the Spanish researchers tracked the health of 64 super-agers and 55 typically healthy older adults, both groups averaging 82 years, looking for disparities in brain scans, mobility tests, mental health assessments, lifestyle surveys, and blood samples.  In line with previous studies, MRI scans showed that the brains of the super-agers did shrink slower than their contemporaries’ brains in a five-year span, better protecting their cognitive abilities related to memory and movement.

The researchers of a 2013 study at Northwestern University compared the brains of 12 so-called super-agers to 10 cognitively normal older individuals between the ages of 50 and 65. What they found was that this group had a fundamental structural difference in the cingulate cortex, a region of the brain important for memory, attention, cognitive control, and motivation was larger in super-agers. 

Since the cingulate cortex is important for many of the cognitive functions that are impaired in Alzheimer’s, researchers think it might be why these ever-healthy elders are resilient. It begs the question whether figuring out how to stop the cingulate cortex from shrinkage could be a key to helping prevent age-related memory loss down the road.

2. Super-agers have a lot of mysterious, giant von Economo neurons

A third superpower of super-agers brains? They seem to have  three to five times the amount of a certain, mysterious neuron called the von Economo neuron than other people. 

These specialized neurons may die off over the course of mild cognitive impairment and Alzheimer’s disease. Scientists believe von Economo neurons are involved in complex cognitive functions. 

3. Super-agers are socially and physically active — and that might protect their brain health 

Because super-agers are characterized in part by living rich, active social lives well into their 80s and 90s, and studies show that mental and physical activities — like cooking or dance classes — keep the brain active, it’s possible these things might all be interconnected. 

This tendency to be socially and intellectually engaged might even play a role, some scientists think, in stimulating the cingulate cortex and the von Economo neurons. 

“Though superagers report similar activity levels to typical older people, it’s possible they do more physically demanding activities like gardening or stair climbing,” neuroscientist Bryan Strange of the Polytechnic University of Madrid said. “It’s also possible that having better brain health in the first place may be what’s responsible for superagers having faster movement speed.”