After 25 years of research, scientists at Northwestern University, USA, have discovered why some adults can live well into their 80s and beyond with near-perfect cognition.
These ‘super-agers’, as the researchers call them, are aged 80 or older, but their memory is as good as that of adults in their 50s and 60s.
Since 2000, scientists have studied 290 of these super-agers, and autopsied 77 of their brains, to understand what makes them so resistant to cognitive decline.
The scientists discovered personality traits that are more common in super agers, compared to the general population. These individuals tend to be highly social and report having strong interpersonal relationships.
But these personality differences are just the beginning. Dr Sandra Weintraub – professor of psychiatry, behavioural sciences and neurology at Northwestern, and one of the authors of a new paper summarising these super-ager findings – said: “It’s really what we’ve found in their brains that’s been so earth-shattering for us.”
In some of the super-agers' brains, the scientists found amyloid and tau proteins (known as plaques and tangles), which play key roles in Alzheimer’s disease. In others, they didn’t.
But none of the brains showed signs of the damage usually associated with those plaques and tangles.
“What we realised is there are two mechanisms that lead someone to become a super-ager,” said Weintraub. “One is resistance: they don’t make the plaques and tangles. Two is resilience: they make them, but they don’t do anything to their brains.”
That wasn’t all. These super agers also had a youthful brain structure. Older brains generally have thinner cortexes – the outer layer of the brain – than younger brains, but these super-agers’ cortexes had not thinned.
In particular, they had very youthful thickness in their anterior cingulate cortex, which is a crucial region of the brain involved in integrating information related to decision-making, emotions and motivation.
And the super-agers had more von economo neurons, also known as spindle cells, when compared to their normal-ageing peers. These neurons are found in the cortex and play a role in social behaviour, emotional processing and self-awareness.
“Our findings show that exceptional memory in old age is not only possible but is linked to a distinct neurobiological profile,” said Weintraub. “This opens the door to new interventions aimed at preserving brain health well into the later decades of life.”
The scientists said that they hoped their research would help uncover new strategies to promote cognitive health and to delay or prevent neurodegenerative diseases, such as dementia, in the future.
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