Margaret remembers how terrible it was having a parent with Alzheimer's disease.

When her mum started putting packets of milk on the stove and the kettle in the fridge Margaret had to make the heartbreaking decision to put her in a nursing home.

"It was terrible to see Mum who was so vital and vibrant just becoming like a vegetable," says Margaret.

Her mum died aged 72.

When Margaret was 80 she signed up for the Australian Imaging, Biomarker & Lifestyle (AIBL) study that is helping researchers better understand the factors that lead to Alzheimer's disease

"I assumed I was probably already on the way and it would be too late to help me," says Margaret.

"But I thought it's such an awful disease and I just wanted to help eradicate it for the next generation."

Now aged 86, Margaret has the mental faculties of people decades younger. ( Catalyst )

But amazingly, regular brain scans have found that Margaret — now 86 — has virtually no chance of developing dementia, says Jo Robertson, a neuropsychologist with the Florey Institute of Neuroscience and Mental Health, who is involved in the AIBL study.

"She doesn't have any of the brain proteins that we know start to accumulate two decades before people start to have symptoms of dementia."

On top of that, tests have shown Margaret's attention and working memory — used, for example, when you reverse a string of digits in your mind — is equivalent to the average 65-year-old.

And her ability to learn and retain new verbal information is greater than 99 per cent of people her age.

"Most people Margaret's age would exhibit a decline in their memory," says Dr Robertson.

She says a "handful" of people like Margaret who seem to be resistant to the usually observed effects of ageing were identified among over 100,000 in the AIBL study.

This week on ABC's Catalyst, Margaret and a team of these so-called "Super Agers" demonstrated they could hold their own against a much younger team, which included Margaret's 61 year-old son Stuart.

The Super Agers were able to memorise the way out of a maze and perform well at other cognitive tests including remembering names and faces.

So can understanding Super Agers help tell us what keeps our minds younger for longer?

It's early days, but some clues are emerging from places like the Northwestern University's Feinberg School of Medicine in Chicago.

Ten years ago a team there led by neuropsychologists Sandra Weintraub and Emily Rogalski flipped its research paradigm on the head.

Instead of looking at what was going wrong to give people Alzheimer's disease they started looking at what was going right for those whose brains weren't ageing the same way.

While the term "Super Ager" is now being used a bit loosely, the researchers say they originally intended it to apply to a person over the age of 80 who scores at least as well as an average 50- to 60-year-old, in particular memory tests.

In all, they've studied 80 Super Agers using brain imaging, cognitive and genetic tests as well as surveys to probe lifestyle and family history in the search for factors that can explain their unusual abilities.



Margaret has had a lifetime of volunteering and now helps out at a community centre. ( Supplied: Margaret McArthur )

With all the evidence that a healthy lifestyle staves off dementia, the team assumed Super Agers would have all led active lives with a healthy diet, says Professor Weintraub, but that expectation was dashed.

"While we had a Super Ager that showed us she could do the splits on the floor in the examination room, we had another Super Ager tell us she just likes to lie on the sofa drinking bourbon every night."



And the Super Agers haven't all been highly educated either.

So is it just the luck of the genetic draw?

No doubt genes play a role, but while Professor Rogalski says the research has thrown up some "intriguing leads" there are no definitive findings on 'Super Ager genes' yet.

Mysteriously, some people appear to be Super Agers despite having genes and biological symptoms that put them at risk of developing Alzheimer's disease, the researchers say.

And others — as seen with Margaret — show a distinct lack of brain proteins associated with Alzheimer's disease.

Professor Rogalski says Super Agers do appear to have a slower rate of thinning of the cortex (the outer part of the brain) compared to normal agers.

Overall, the thickness of this part of the brain is similar to that of 50- to 60-year-olds, and a part of the cortex called the anterior cingulate gyrus is actually thicker in Super Agers than in the younger group, and has more of a special type of brain cell called Von Economo neurons.

This part of the brain and these special neurons are thought both to be important in social interactions, Professor Rogalski says.



Strong social networks could play a role

Interestingly, the Chicago researchers also report Super Agers value strong social networks and keeping positive, warm and trusting friendships.

"This fits with a lot of literature out there talking about the negative consequences of loneliness and the importance of social engagement," says Professor Rogalski.

Watch how the Super Agers performed against their younger counterparts in this maze on this week's Catalyst. ( Catalyst )

Margaret certainly appears to have strong social networks. She's had a lifetime of volunteering — now at an art gallery and a community centre that helps homeless people.

She does pilates, goes to Probus Club, plays petanque and sings in a choir. And when she's not catching up with friends she's busy with her family and grandchildren.

"I'm looking forward to the time when I'm bored," she jokes.

Kaarin Anstey of the University of New South Wales says studies of older adults have suggested social engagement is protective against dementia.

But she is cautious about putting it in the same basket as the likes of well-proven protective factors like a good diet, physical exercise and learning new things.

"It's a nice feel-good story but we have to be careful," says Professor Anstey, who has a PhD student studying a group of Super Agers identified in the Personality and Total Health (PATH) Through Life study.

She says it's possible that as people's memory slowly declines they get less confident with physical and social activity. This would mean social isolation could be a product rather than a cause of deteriorating brains.

But Professor Rogalski says Super Agers value social relationships more than even their healthy normal counterparts who are not withdrawing socially, supporting the idea that social engagement is a protective factor against mental decline.

The "chicken and egg" question is more relevant when comparing Super Agers to people of the same age who have more serious memory problems, she says.

Professor Rogalski says early indications also suggest Super Agers demonstrate resilience in the face of life's slings and arrows.

"It seems like our Super Agers find the positive and move on," she says.

Most agree there's not likely to be a simple answer on what makes a Super Ager.

"I think we should steer away from trying to find one magical thing that is going to keep us free and clear from Alzheimer's disease," says Professor Rogalski.

"It's likely to be complex and the goal is to identify as many protective factors as we can … things that are helpful."

Margaret and her choir buddies ( Supplied: Margaret McArthur )

She says research on the remarkable Super Agers is really just beginning.

"It's taking a different vantage point and generating new hypotheses."

And perhaps it is also a more optimistic vantage point — not least for researchers, who point to the fall in the rates of dementia in older Australians as a sign we're taking more heed of lifestyle messages.

The Florey Institute's Dr Robertson feared old age until she met the Super Agers. Now she suggests we can all be inspired by them.

"I think that what these people are telling us is that dementia is not an obligatory part of ageing," she says.

As for Margaret, she's getting on with her busy life — volunteering, socialising, emailing and even banking online — struggling with managing online passwords like the rest of us!

Everyone Margaret works with is much younger than her, but that doesn't faze her.

"I just do what I like doing and enjoy the company of people who enjoy doing what I like doing," she says.

"I really don't think of people by their age. I think about them by their attitude to life."