“Superagers” — older adults whose memory skills are on par with those of youth — have long baffled neuroscientists. But researchers in Boston conducted a new study that proposes new insights as to how this phenomenon arises.
Researchers think understanding how superagers are able to preserve their mental abilities may help them find clues to prevent the onset of neurodegenerative diseases, such as Alzheimer’s, says Jiahe Zhang, a graduate student at Northeastern University in Boston and lead author of the study.
“By isolating those superagers we might be able to really zoom-in on the factors that are common among them that can help a general population to perhaps achieve better ageing,” says Zhang.
The global incidence of Alzheimer’s disease and other dementias was estimated at 43.8 million in 2016, up from 20.1 million in 1990, according to a 2018 study published in The Lancet Neurology.
For the new study, published in Cerebral Cortex, the researchers used a brain scanning technique known as functional magnetic resonance imaging (fMRI) to detect activity in the brain as superagers (aged 60 to 80), typical older adults (aged 60 to 80), and young adults (aged 18-35) completed memory-related tests. Additionally, the researchers compared how closely connected, or “coupled”, specific networks of the brain were across each of these groups, a marker for how efficiently information travels between brain regions. They were especially interested in two brain networks that have a role in encoding and processing memory, which are known as the default mode network (DMN) and salience network (SN).
The results showed that superagers and young adults were similar in how strongly connected their DMN and SN were. Zhang adds that the stronger the connection between these two networks were, the better participants performed in memory tests.
Bart Strooper, director of the Dementia Research Institute at University College London, thinks there is still much to learn about the mechanisms underlying the high performance of superagers: “It’s interesting work, but it does not explain why this connectivity is maintained,” he wrote in an email. “What interests me is the genetic basis for this phenomenon.”
Another unresolved question is whether superagers start with a higher level of memory-related abilities, or whether they have developed mechanisms to fight off the mental decay usually associated with aging.
“It’s possible that these superagers were ‘superyouths’ in their 20s,” said Zhang.
What does seem clear is that superagers share common traits and personalities. “We get a sense that superagers are more willing to persevere in the face of challenge, instead of taking it as a threat and backing off,” says Zhang. She adds that, from her experience, superagers tend to be more motivated, perseverant, and curious about the research they participate in.
Zhang highlights that superagers are probably not as uncommon as we might presume: “If, really, you look into any sample you’ll probably find some superagers.”
“Even anecdotally — there is always that person in their 80s who can perfectly recall what groceries they got from the supermarket, or where they parked their car every day,” she adds.