There is great value in taking up a new hobby to boost brain health – the key is to find something that appeals to you. Photo / 123RF
Research suggests certain characteristics may be linked with the disease – here’s what you can do about it.
Can your personality affect your risk of dementia? It appears so, according to a new study of 44,000 people aged between 49 and 81 which rated them according to five key personality traits – conscientiousness, extroversion, openness to experience, neuroticism and agreeableness.
Researchers at the University of California, Davis found that extroverts or even just those with a more positive outlook on life were less likely to develop dementia, along with those who are more conscientious. Conversely, those who are more neurotic or prone to feelings of anger, guilt or anxiety were at a higher risk.
Scientists believe that this is linked to the concept of cognitive reserve, an inbuilt resilience within the brain driven by genetic, personality and various lifestyle factors, making it more resistant to the disease. Extroverts, for example, are far more likely to engage in social activities which are known to help boost cognitive reserve, while neurotics may be more prone to pushing people away and becoming isolated.
Understanding cognitive reserve is particularly crucial given the growing impact that dementia is predicted to have on society. Earlier this month, the UK’s biggest dementia organisations launched a new review called the Geller Commission to look at ways of tackling the growing crisis. They presented a grim new statistic: dementia will likely cost the UK economy over £50 billion a year by 2025, with more than a million people projected to be living with the disease.
Emily Rogalski, a neuroscientist at the University of Chicago, explains that, with age, the brain’s outer layer begins to thin, while toxic protein fragments linked to dementia, known as amyloid plaques or tau tangles, begin to accumulate in various parts of the brain.
“The idea of cognitive reserve is that people don’t experience the bad effects associated with those things because they’re resilient to them,” says Rogalski.
She cites famous studies of nursing home residents who have undergone brain scans and have been found to have a high degree of plaques in their brains, levels normally associated with Alzheimer’s. Yet they still experience no memory problems or changes in their everyday life, due to their cognitive reserve.
“We look at that and think, ‘Gosh, how are these people resilient to that?’” says Rogalski. “But they are.”
We’re still learning more about cognitive reserve, but it’s thought to be an extra capacity that allows your brain to improvise and work its way around any age-related damage, which means it can continue functioning optimally for longer.
So, what do we know about cognitive reserve and how can you acquire it?
Our memory peaks between the ages of 30 and 40. After 50, studies have shown that total brain volume begins to shrink, particularly in regions linked to complex thought processes and learning, which is why problems with remembering names or retrieving words tend to become steadily more common with age.
But this decline is not inevitable. Joyce Shaffer, a behavioural scientist at the University of Washington, says that studies have been done on some centenarians which showed that their brain function remained equivalent to the average 50- or 60-year-old.
There are some biological explanations as to why certain people seem to have greater cognitive reserve. Henne Holstege, an associate professor at Amsterdam UMC who runs the 100-plus study of cognitively healthy Dutch centenarians, says that while they see ageing-related changes in the brains of the study participants, they still retain high levels of myelin and other proteins. These are protective fatty sheaths, often referred to as white matter, which form around neurons. “We see they have much higher levels of myelin than you would expect for their age,” she says.
In addition, dementia is also linked to the slow loss of dendritic spines, tiny protrusions that connect our brain’s cells or neurons with other neurons. Research has suggested that dendritic spines are longer in people with greater cognitive reserve, and certain proteins such as neuritin and twinfilin-2 are believed to help maintain spine length and density.
Neuroscientists believe that activities which stimulate the brain cognitively, such as continued intellectual and social engagement through later life, helps to maintain high levels of these proteins in the brain, which in turn help preserve neural connections.
Researchers have found that higher educational achievements or greater career success can help to build cognitive reserve.
“Someone who has done lots of education has developed more brain strategies,” says Andrew Sommerlad, an associate professor at UCL Division of Psychiatry. “They’ve exercised their memory more, they’ve learned more language skills and they’re likely to have better resilience so they can cope with damage to their brain for longer.”
But before you embark on that PhD, cognitive reserve is not all about educational and professional success. Rogalski leads the SuperAging Research Initiative across five cities around the United States and Canada, which follows people over 80 who have the same memory capacity as individuals who are many decades younger.
She cites higher levels of social engagement through mid and later life as being strongly linked with better cognitive reserve and a 30 to 50 per cent lower risk of dementia. This is thought to be because socialising is a workout for the mind, involving remembering faces, names, picking up on social cues and asking questions, which all exercise the brain’s capacities.
“Spending time with other people in a social context is one of the best exercises you can do for your brain because it requires you to use language, to recall things that are important, and to use humour and entertain people,” says Sommerlad.
There is also great value in continuing to find ways to challenge yourself. While becoming proficient in a language or learning an instrument are often cited as exemplary ways of doing this, Rogalski says it is really all about finding something that particularly appeals to you.
“There was a great study a few years ago that really drove this point home,” she says. “They had one group who learned to knit for the first time, and another who took a photography class, and the question was what’s better for your brain? They actually found that knitting and photography were similar. The key was that in both instances they were challenging their brain and learning something new. That unpredictability and thinking on your feet is good.”
Eating a diet high in sugar and processed foods is known to disrupt many of the brain’s functions through generating persistent inflammation, which can reach the mind through the bloodstream. Instead, researchers recommend nutritional regimes such as the Mediterranean diet, which is low in saturated fat – protecting the heart – and also high in fibre.
“A heart-healthy diet is a brain-healthy diet,” says Rogalski. “That adage is still very meaningful, since you are controlling blood pressure.”
On the other hand, getting plenty of good quality sleep can boost your cognitive reserve. One study found that non-rapid eye movement, a particular phase of deep sleep, is important in this regard, possibly because it helps with clearing toxins and maintaining the neural connections involved in memory formation.
Physical activity is also known to play a crucial role in cognitive reserve, exercise helping to maintain heart health and blood flow to the brain, as well as increasing levels of crucial enzymes such as brain-derived neurotrophic factor, which helps with memory formation.
Cognitive reserve is far more dynamic than you might imagine. It has been likened to the software of a computer, something that can be continually upgraded throughout our lives.
This all means that it’s never too late to take steps to boost your cognitive reserve, whether you’re in midlife or your 80s and 90s.
“It was once thought that the only path for ageing was to become old and senile,” says Rogalski. “But we now know that there’s so much new learning that’s possible, and we’re able to celebrate super-agers like people who are over 80 and still have the same memory performance as people in their 50s or younger. That really changes our expectations of ageing.”
Of course, our chances of living to 100 still depend quite heavily on our genes. Holstege estimates that 60 per cent of our likelihood of becoming a centenarian depends on our DNA.
But lifestyle and mindset still play a critical role. Perhaps the biggest lesson we can learn from people over 80 who are still functioning well is that they tend to lead highly active lives, whether that’s continuing to work part-time or volunteering or even travelling the world.
“We have a lady in our study who was most recently hiking and swimming in Patagonia this spring at the age of 92,” says Rogalski. “There’s another gentleman who was a retired lawyer. He got bored and so he went back to school and studied for an accountancy licence.
“He’s 87 and he works for a few months of the year, helping people with their taxes, which he finds to be a great way of staying connected socially and still having some purpose, but also time for his retirement,” says Rogalski.
Finally, many super-agers tend to be flexible and are able to find ways of forming connections with people who are many generations younger than them, to help maintain their social circle.
“One of our participants told us that he wanted to connect with his grandchildren but he had to recognise that they didn’t know about Frank Sinatra or Franklin D Roosevelt,” says Rogalski. “So he learnt about Taylor Swift and modern rappers. That type of adaptability is good for your brain.”
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