Most research on memory loss in the elderly focuses on dementia, Alzheimer's disease or other brain diseases.
But neuroscientist Emily Rogalski from Northwestern University's Feinberg School of Medicine knew there is great variation in how good memory is in older people. Most have memory loss to varying degrees, but some have strong memories, even well into old age.
Rogalski wanted to know just how good. So she began recruiting volunteers age 80 and up from the Chicago area to test their memories. The study appeared in the Journal of the International Neuropsychological Society.
The volunteers came into Rogalski's memory lab and were given a barrage of tests. Rogalski says she told the participants: "We want individuals who are over age 80 to perform on memory tests like 50- to 60-year-olds, or better."
Participants had to memorize a list of random words and recall the words some time later. Or they listened to stories and were later tested on the many small details in them. "The memory tests were very hard," says Lou Ann Schachner, 84, who volunteered for the study along with her 81-year-old husband, Jay.
What Rogalski found was that some of the elderly participants had outstanding memories; they did as well as — if not better than — people in their 50s.
But such individuals who do really well on the memory tests are not common, she adds. Of those who came in to have their memories tested, only about 1 in 10 had exceptional memories. This group Rogalski calls "superagers."
Once this group of superagers was identified, Rogalski was eager to find out what explains their exceptional memories. Her first step was to see if the brains of the superagers looked any different than those of other 80-year-olds.
Each superager was given several MRI scans. Rogalski then analyzed the brain pictures, exploring the outer layer of the brain called the cortex, which is critical for thinking and memory. The cortex is comprised of dense layers of nerve cells, and its thickness indicates the health of the brain.
In Alzheimer's, for example, the cortex gets thinner and shrinks. But in the superagers, Rogalski says, "What we found was quite remarkable. We found that the [cortices of] individuals who are superagers look more like those of 50- to 60-year-olds." There was no significant thinning or shrinkage of the cortex in the superagers, compared to people 20 or 30 years younger.
At first, Rogalski didn't believe what she had found. So she analyzed the MRI scans again, confirming the findings.
"Then we found something even more surprising, which was even harder to believe," she says. "In an area called the anterior cingulate of the brain, it was actually thicker in the superagers than it was in the 50-year-olds." The anterior cingulate is a small brain region important for attention and memory.
A youthful cortex and thicker cingulate suggest to Rogalski that these two brain regions have been spared the typical age-related shrinkage, which may be what protects against the memory decline seen in most elderly people. Superagers also have fewer risk genes for Alzheimer's than typical 80-year-olds, she notes.
But there may be other explanations for the exceptional memories of these superagers. Perhaps they've always had bigger brains; maybe they have an excess of reserve that the majority of elderly people do not. Another possibility, Rogalski says, is that the memory of a superager declines much more slowly.
To check out these possible explanations for why 1 in 10 individuals over age 80 has an exceptional memory, Rogalski has recruited 30 more 80-year-olds with exceptional memories. She's currently in the process of analyzing their brain scans.
So stay tuned, she says. But for now, the take-home message is that the loss of memory as we age is not inevitable.
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In Your Health today, two stories on the aging brain. There's been a lot of scientific research focusing on memory loss in the elderly due to dementia or Alzheimer's disease. But in a provocative new study, researchers have flipped this around. They're looking at a group of seniors who've retained strong memories, similar to people two or three decades younger.
Now, as Michelle Trudeau reports, the scientists are trying to understand why.
MICHELLE TRUDEAU, BYLINE: The Schachners just celebrated their 43rd wedding anniversary last week.
LOU ANN SCHACHNER: I'm Lou Ann Schachner. I'm 84.
TRUDEAU: And Jay Schachner?
JAY SCHACHNER: I'm 81.
SCHACHNER: I'm the older woman here.
TRUDEAU: The Schachners are just two volunteers in an ongoing study at Northwestern University Feinberg School of Medicine, directed by Emily Rogalski.
EMILY ROGALSKI: I'm a neuroscientist by training.
TRUDEAU: Rogalski studies memory in the elderly. There's great variability she says in memory as we age. And she wanted to know why some elderly have strong memories, while others - most others - do not. So she set-out to find elderly individuals with exceptional memories for their age. To test their memories, she raised the bar pretty high.
ROGALSKI: We said we want individuals who are over age 80 to perform on memory tests like 50- to 60-year-olds, or better.
TRUDEAU: Of the volunteers over age 80, only about 10 percent had exceptional memories.
ROGALSKI: So it kind of tells you that this is a little bit rare.
TRUDEAU: The group, average age 83, Rogalski calls super-agers, like Lou Ann and Jay Schachner. Their memories are as strong as people 20 or 30 years younger than they. Jay was a patent attorney; retired but got bored. so took up tax law. And at 81, he goes to work every day.
SCHACHNER: It gives me a chance to meet people and it's challenging. You talk about mental stimulation, keeping up with all the changes in the tax laws is a challenge in itself. But it's fun. If it weren't fun, I wouldn't do it.
TRUDEAU: Researcher Rogalski wanted to find out if there is something unique about the brains of Jay and LuAnn and the other super-agers
ROGALSKI: And so we asked a very simple question.
TRUDEAU: Do the brains of super-agers look like the brains of younger individuals? First, Rogalski used MRI to explore the cortex, that part of our brains central for thinking and memory. Its thickness varies from person to person.
ROGALSKI: And if we measure the thickness of the cortex, it gives us a proxy measure of the health of the brain.
TRUDEAU: In Alzheimer's, for example, the cortex gets thinner.
ROGALSKI: We also know, through the course of normal aging, the cortex shrinks.
TRUDEAU: But the cortex of these super-agers had not thinned, but rather showed something very different.
ROGALSKI: And what we found was - quite remarkable, in that we found that the brains of individuals who are super-agers look more like those of 50- to 60-year-olds.
TRUDEAU: A thicker cortex in these 80-year-olds is associated with a youthful memory. Well at first, Rogalski didn't believe it.
ROGALSKI: And then we found something even more surprising, which was even harder to believe, was that in an area called the anterior cingulate of the brain...
TRUDEAU: An area important for attention and thus for memory.
ROGALSKI: ...it was actually thicker in super-agers than it was in 50-year-olds.
TRUDEAU: A youthful cortex and a thicker cingulate may be related to why these super-agers are spared memory decline.
Genes too may play a role, Rogalski says, noting that the super-agers also have an important gene profile - they have fewer risk genes for Alzheimer's than typical 80-year-olds.
CLAUDIA KAWAS: I think that's very titillating.
TRUDEAU: Neurologist Claudia Kawas directs a study on 90-plus-year-olds at the University of California, Irvine. She cautions this new research on super-agers is small, with only of 12 individuals. But...
KAWAS: It suggests that they have found a biological correlate of the incredibly good cognition that these individuals have.
TRUDEAU: Kawas wonders though if these super-agers may have always had bigger brains, had an excess of reserve that others don't have. Or, that their memories may be declining much more slowly. Emily Rogalski is seeking explanations too, and so has recently recruited 30 more 80-year-olds with exceptional memories. She's in the process of analyzing their brain scans. So stay tuned, she says. Then adds, for now, the take-home message is that loss of memory as we age is not inevitable.
For NPR News, I'm Michelle Trudeau. Transcript provided by NPR, Copyright NPR.