Scientists have long assumed that fading memories are just a normal part of aging. But a new study suggests that certain 80-somethings can remember every bit as well as people much younger.
Researchers from Northwestern University found that these mentally sharp octogenarians, dubbed SuperAgers, also have brains that look very much like those of people in middle-age, according to the study published in the Journal of International Neuropsychological Society.
For the new study, researchers used MRIs to look at the thickness of the outer layer of the brain, a region called the cortex, in SuperAgers, normally aging 80-somethings, and healthy 50- to 65-year-olds.
What they found was intriguing – the SuperAgers had brains that looked very much like those of the younger people in the study and in some ways looked even healthier.
"We were very surprised at that," says study co-author Emily Rogalski, an assistant research professor at the cognitive neurology and Alzheimer's disease center at the Northwestern University Feinberg School of Medicine
"When we looked at cortical thickness, we were very shocked to see that even with a 20- to 30-year age gap, there was seemingly no difference in the cortical thickness," she says. "In normally aging 80-year-olds, you see quite a bit of cortical thinning, even among those who are still performing normally for their age."
The cortex is key since it's involved in memory, attention, and complex thinking, also known as executive function.
Rogalski and her colleagues tested the memories and cognitive skills of 12 Chicago-area SuperAgers and 14 middle-aged volunteers. They then scanned all 26 with a 3D MRI machine and compared both groups of scans to images from normally aging 80-somethings that came from a national data bank.
Finding a group of SuperAgers was no easy task, however.
While plenty of 80-somethings showed up at the lab saying their memories were great, most didn’t remember as well as healthy middle-aged people do.
"We weren't even sure if we would be able to find any SuperAgers since we set the bar so high," says Rogalski. "They had to be as good as 50- to 65-year olds. We screened 300 people who thought they had good memories and found 30 SuperAgers."
And the MRIs showed why the 30 SuperAgers were so mentally sharp.
Rogalski found the SuperAgers' cortexes were as thick as those in people 20 to 30 years younger.
Experts believe that shrinking cortexes are a sign that cells are shriveling and dying with age - sometimes killed off by the same abnormal proteins as you see in Alzheimer's brains. One finding that really surprised Rogalski and her colleagues: a region deep in the brain, called the anterior cingulate was actually larger in SuperAgers than it was in middle-aged folks.
The anterior cingulate is very important for attention. Studies have shown that one of the reasons memory fails as we age is that we can't focus as well as we did when we were younger.
"If I were to tell you ten things you need to pick up at the grocery store and then the phone rang and you got distracted talking to your best friend you'd probably find it hard to remember those ten things when you got to the store," Rogalski explains. "That wouldn't mean your memory was bad, but rather, that you weren't able to focus on the task."
Rogalski hopes the new research on SuperAgers may help scientists unlock the secrets of these "youthful brains" and find ways to protect us against from age-related damage.
"This is the first step in a new way of looking at this - a road less traveled in aging research," she says. "Instead of looking at what is going wrong with the brain, we want to know what is going right."
As for why some people are SuperAgers and some aren't, the research team can't provide any answers at this point. It could be all related to genetics or a combination of genes and the environment: no clues popped up during the SuperAger's interviews that set them apart from people who had aged normally.
But the question of whether there's something we can do to keep mentally sharp is something Rogalski is hoping she'll be able to answer as she continues to study the SuperAger phenomenon.