Ever put your mobile phone down and can't think where you left it? Wondering if you closed the door behind you when you left the house? Met an old friend but suddenly can't recall their name?
We're all victims of these "senior moments" as some like to call them. They're the nagging little incidents of momentary forgetfulness that we put down to just that: forgetfulness.
However, research now suggests that there may be more to such minor memory failings than we think and that if we don't train our brains to stay sharp, then cognitive decline and diseases such as dementia can strike much earlier in life than experts previously thought.
A joint study from the Centre for Research in Population Health in France, along with University College London, suggests that brain skills such as memory and reasoning may go into decline at just around the time life is said, by many, to really begin – in our forties.
During a 10-year period, more than 3,000 people between 45 and 70 years old were tested by the researchers for indicators of cognitive decline. While the results showed that a slowdown in thinking speed was greatest in the older subjects, all age groups showed some decline, with signs first occurring for some folk in their mid-forties. In the UK, the news has been met with a pessimistic response: "Life ends at 45" read one newspaper headline.
It is news that's especially pertinent to people in the UAE, where public health campaigns regarding brain diseases such as Alzheimer's have been scarce. "As a relatively young population, there is low awareness of Alzheimer's disease in the Middle East," explains Dr Stefan Diez, a consultant neurologist at the Neuroscience Center of Excellence at the American Hospital in Dubai.
Diez, who recently presented an update on the situation in the Middle East following the World Alzheimer's Awareness campaign, explains that measurable data on the local scale of dementia is sparse. "But we do see early incidence – up to 10 years earlier than in the West - of other age-related diseases such as stroke and heart disease where statistics are available," he says.
"This suggests that the Middle East may face the burden of Alzheimer's disease and related dementias much earlier than in the West," adds Diez. "The good news is that our ability to predict the disease in patients – and ultimately the potential to treat the disease – is improving rapidly."
The exact cause of Alzheimer's disease isn't known. Possible triggers could be genetic, environmental and lifestyle factors that affect the brain over a period of time. Symptoms include a failure of brain functioning, thinking, remembering and reasoning that progressively worsens.
But health experts have been quick to assure us that "forty-somethings" people shouldn't be giving up on life just yet. In fact, far from signalling a decline into dementia, such a study can be just the motivation we need to sharpen our mental faculties and ensure we're quick-witted and able to recall events.
A counter-study in California, published in January, says that the sooner you start challenging your little grey cells with brain games, reading material or new languages, the greater your chances are of avoiding the disease in later life.
"Rather than simply providing resistance to Alzheimer's, brain-stimulating activities may affect a primary pathological process in the disease," explains Dr William Jagust, a professor at the University of California at Berkeley's Helen Wills Neuroscience Institute. Jagust's study looked at the link between beta-amyloid – a protein that accumulates in the brain – and Alzheimer's.
Beta-amyloid has been identified as a chief suspect by those looking into the causes of the disease. The researchers found a significant association between higher levels of cognitive activity over a lifetime and lower levels of beta-amyloid in scans carried out on people. "This suggests that cognitive therapies could have significant disease-modifying treatment benefits if applied early enough, before symptoms appear," says Jagust. That's a plus for young people looking to keep their wits about them in later life. It's also something that the creators of "brain training" techniques will be pleased to hear.
"Brain training is the concept that exercising the brain helps keep it fit, in a similar way to going to the gym helps to keep your body fit," explains Dr Gareth Moore, a specialist in artificial intelligence and the author of more than 20 books on brain training. "The central principle of brain training is that cognitive exercises not only help improve your ability at the task you're doing, but also improve your overall mental fitness. This can help counter a natural decline in brain function that comes with ageing."
"Upgrading your mind is all about challenging yourself with new concepts and experiences," says Moore. "Anything you can do with only minimal thought will fail to stretch you."
Moore suggests we play puzzles and games, travel to new places and try to do something new every so often. "Also try to use your memory where you can, so try memorising your shopping list instead of writing it down, or learn the phone numbers or birthdays of friends and family," he adds.
The focus on brain training has also given rise to a wave of computer games marketed as being shortcuts to attaining a longer cognitive lifespan. "But evidence of such a benefit isn't in yet, and I think it will never come in," argues Tom Stafford, a lecturer in psychology at the University of Sheffield and a co-author of The Rough Guide to Brain Training.
"These games are a total waste of money, given that a walk in the park with a friend will benefit you more mentally, and is free. By all means do puzzles if they challenge you, but don't pay lots of money for special 'brain training' puzzles – the whole industry is somewhere between hopeful speculation and a rip-off."
According to Stafford, the best way to stop the brain rot is to challenge it more holistically – through mental, physical and social exercise. "The brain is a machine that runs on blood, and so the most important thing you can do to have a healthy brain is to have a healthy blood supply. That means physical exercise, not mental exercise. The evidence supports this – people who did exercise in their thirties are less likely to get dementia in older age, for example."
A healthy body, it seems, is the best route to a healthy, long-living mind too.