Researchers are studying the brains of older adults whose brains resist the usual wear-and-tear of cognitive decline.

The good news is that social scientists at Northwestern University have identified a group of older adults they call “SuperAgers,” whose cerebral cortexes shrink at half the rate of most older people.

The bad news is that so far it isn’t clear just what it is that these SuperAgers — all 80 or older — have or do that keeps their level of cognitive decline so low.

Researchers already knew SuperAgers’ brains tend to retain more brain volume and typically don’t show the same wear-and-tear as other older adults.

This research was an effort to determine why.

The findings were published in the April 4 edition of the Journal of the American Medical Association (JAMA).

Read more: Study breaks down aging process »

The team used MRI to measure the thickness of the cortex in 24 SuperAgers and 12 cognitively average peers who were the same age and had the same level of education.

Over 18 months, the annual decline in thickness between the first and second visits for the SuperAgers was 1.06 percent and 2.24 percent for the control group.

“We’re trying to understand what it is about them and eventually replicate it,” Amanda Cook, a clinical neuropsychology doctoral student in the laboratory of Emily Rogalski and Sandra Weintraub at Northwestern, told Healthline. “It’s not like all the people in that group eat blueberries every morning.”

To confound the picture further, some participants say they never touch alcohol, while others swear by their daily cocktail.

The normal aging process involves shrinking of the brain.

“But what’s unique about these people? There’s not much research on cognitive decline” in this population, Cook said.

“We tried to control outside factors,” Cook said. “Both groups of people had no difference in pre-morbidity. They had the same IQs, the same amount of education.”

Nor was there a difference in their rates of smoking, obesity, and diabetes.

“We don’t have MRIs of their brains when they were 50 or 60, so we can’t tell if they always had bigger brains,” Cook said.

Read more: Everything you ever wanted to know about the brain »

Dr. Heather Snyder, senior director of medical and scientific operations for the Alzheimer’s Association, called the study interesting.

“We want to know how they are different, and how we can replicate that for other people,” she told Healthline.

“Alzheimer’s is the sixth leading cause of death in the country and the only one in the top 10 for which we have essentially no treatment,” Snyder said. “Of people over 85, 1 in 3 will develop dementia.”

What’s known is complicated and not fully explained. Snyder cited blood pressure as an example.

“High blood pressure in middle age is bad. It’s linked to cardiovascular disease. But in old age, high blood pressure is good because it feeds the brain,” she explained.

Behind the scientific discoveries is the willingness to pursue them.

“Continued federal funding for studies is crucial,” Snyder said. “We are making progress and the need will only grow,” she said.

Read more: Why there hasn’t been a new Alzheimer’s drug in 10 years »

Researchers in the field are also encouraged.

William E. Sonntag, PhD, professor and director of Reynolds Oklahoma Center on Aging at the University of Oklahoma Health Sciences Center, discussed the issue with Healthline.

“What do these people have that the rest of us don’t? That’s the key question. And this will undoubtedly be the focus of studies over the next several years,” he said.

Sonntag listed some possibilities:

  • Are there are factors in the blood that help to maintain brain volume?
  • Is there a particular diet (less likely although still possible)?
  • Are there specific genes that contribute to this effect? This is likely, although difficult to pull all the genetic effects out since it’s probably an interaction among several genes.
  • Do these SuperAgers have better vasculature (more blood vessels) in the brain (cerebrovasculature) that are critical for maintaining brain volume and function? If the blood vessels deteriorate, so does the brain. This may be why exercise appears to have a beneficial effect.

Sonntag thought the study offered intriguing possibilities.

“Any time that there can be a clear marker or predictor of cognitive dysfunction, the field moves forward. We can then use this marker as a way to test interventions,” he said.

Sonntag said the key to scientific research and the development of pharmaceutical agents that may result in maintained function is to find the specific cellular mechanisms that make this happen.

“Once the cellular mechanisms for this effect are identified, drugs can be developed to intervene,” he said.

In the New England Centenarian Study, Dr. Thomas Perls, a geriatrician at Boston University, suggested another way to look at this field of study.

In a story in Time magazine in 2004, he was quoted as saying, “It’s not ‘the older you get, the sicker you get,’ but ‘the older you get, the healthier you’ve been.’ The advantage of living to 100 is not so much how you are at 100, but how you got there.”