One certainty that comes with ageing is that our physiology will eventually betray us. Lithe and supple bodies deteriorate over time: faces become wizened; aches become dull and persistent; our internal systems begin to stutter. To delay this physical decline, medical professionals suggest adhering to a good diet and exercise regimen. But what about our brains? How do we protect mental agility as we enter our twilight years?

While cognitive decline and neurodegenerative diseases such as Alzheimer’s or dementia are not an inevitable part of the ageing process, memory lapses and mild skittishness are par for the course. Multitasking in particular seems to induce a kind of ambient terror: navigating a supermarket aisle and its attendant stimuli is hard enough, without forgetting why you were there in the first place. That these symptoms can disable our mental faculties even momentarily is disconcerting. So scientists began to wonder: what if these effects could be reversed? Could shrivelled brains become supple again?

Neuroscientist Adam Gazzaley spent years studying how the brain functions but found he was more interested in how a person’s cognitive abilities could be improved. “I had this idea that we could build a custom-designed video game that targeted deficits in attention and memory in older adults,” says Gazzaley. So he called his friends who worked at LucasArts (the video-game publishing and licensing outfit of Star Wars creator George Lucas) and developed NeuroRacer, a simply designed car-driving video game that tested users on their ability to identify relevant signs and ignore distracting ones. Octogenarians may seem unlikely gamers, but Gazzaley says many NeuroRacer users were enthusiastic about playing the game. “A lot of them did not have any interaction with technology, and here they were playing a video game – and getting really good at it. That was empowering to them.”

In the past few years, a growing body of research has emerged around the therapeutic potential of video games – particularly first-person shooter games. Several studies have shown that players of games such as Halo or Call of Duty performed better in visual tests, spatial reasoning and decision-making than those who played games such as Tetris. Participants in these studies were non-gamers who played for a limited amount of time (one hour a day for 10 days). In another study, undertaken by scientists at the University of California, Berkeley, 40 hours of playing Medal of Honor improved visual acuity so much that it cured the subjects’ amblyopia (lazy eye). However, it should be noted that such brain-training studies can be hard to replicate: scientific research is particularly prone to the “file drawer effect”, which refers to the systemic bias that occurs when studies that show inconclusive or negative results go unpublished.

These issues aside, Gazzaley wanted to explore the links between video-gaming and cognitive function, saying: “We were actually inspired by these results.” His team was keen to use the principles of first-person shooting games “minus the violence aspect”. And although NeuroRacer contains no violence or shooting, its results were promising: they showed improved performance on memory and attention tests outside of NeuroRacer. “Multitasking in a distracting environment is a type of skill that we know declines with ageing,” says Gazzaley. And so, over a period of four years, he and his team conducted a research study around NeuroRacer and used placebo controls to determine whether the video game provided any therapeutic effect on cognitive ability. Central to this hypothesis is the concept of neuroplasticity, which refers to the brain’s ability to change and adapt its structures as a result of new experiences and acquiring new skills.

“We’ve known about plasticity for a while,” says Gazzaley, “but a lot of views suggest it is something that occurs in the younger brain.” His findings, which were published in an article called “Game Changer” in the scientific journal Nature last year, suggest that older brains not only retain this plasticity, but that training gives them the potential to “outperform” younger brains. Neuroimaging showed that brainwaves in older players’ prefrontal cortex looked remarkably similar to brain waves emitted by younger, twentysomething brains. Equally impressive was that users of NeuroRacer “improved on other skills that were not directly targeted by the game, including working memory and sustained attention”, says Gazzaley.

Old brains, it would seem, can be taught new tricks, but neuroscientists urge that such results be interpreted with caution, as the field of research is still a nascent one. Annukka Lindell, a senior lecturer at La Trobe University’s school of psychological science, says that while brain-training helps people to “perform well in brain-training tasks”, evidence of its potential to transfer skills into real life – or to “generalise outside of the brain-training itself”, as Lindell says – is limited. Gazzaley himself told The New York Times there was a “big leap” in terms of what was achieved in his laboratory and what could be achieved in real life. Such claims, he told the paper, needed to be backed by hard science.

Yet these concerns have failed to deter a flurry of companies from turning the concept into a multimillion-dollar industry, offering brain-training to eager consumers, people with attention deficit hyperactivity disorder, and schoolchildren. (Cogmed is one such company that offers its services to more than 1000 primary and secondary schools around the world.)

For the past fortnight, I’ve been experimenting with various brain-training apps. The one I used most was Lumosity, an app that offers users a series of exercises designed to test and improve one’s memory and multitasking ability. I used only the games that were bundled with the app free, but there are more than 50 million users worldwide who pay $US15 a month. The app is downloaded 50,000 times a day, and the company, Lumos Labs, has grown 150 per cent year on year since it was established in 2005. And there are plenty of competing apps keen to capitalise on what is fast becoming a growth industry: Cogmed, Jungle Memory, CogniFit, Elevate, Eidetic and Personal Zen all claim to improve cognitive function – and some even say they help users to gain a higher IQ.

Once you’ve signed up, Lumosity asks you to choose the parts of your brain you’d like to improve (recalling the locations of objects; remembering people’s names; learning new subjects quickly and so on), followed by the aspects of your attention that need more work (maintaining focus on important tasks; avoiding distractions; concentration). It also poses similar questions about one’s mental speed, flexibility and capacity for problem-solving. The app then devises a program of mental workouts, to be completed every day, that supposedly “allow anyone to achieve their full potential”. The games, which have eye-catching graphics and cute names such as “Lost in Migration” and “Pinball Recall”, never felt arduous. But playing them reinforced a very narrow concept of what the brain is and what it can achieve.

For some people, there may be some psychological reward in seeing one’s scores in a brain-training game improve over time. But the more I practised these games, the more it began to resemble cramming for high-school exams. Lumosity and apps like it aren’t concerned with nurturing intrinsic intelligence, for instance, nor learning for learning’s sake. The app is more like a gymnasium for the mind, where the games allow you to pump the iron of your brain – although the benefits appear dubious. I can’t say with certainty whether Lumosity enhanced my mental abilities, but I’m confident the app did make me proficient in nailing these specific games.

Still, doing any activity to stimulate the brain is better than nothing. The important thing, says Lindell, is that brain-training happens daily. “Anything that challenges you, like learning a new skill rather than sitting passively and receiving information, is changing your brain,” she says. Think learning a language, doing a sudoku, calculating your taxes. She cites research that shows that people who play musical instruments have activated different connectivities in the brains compared with others.

Brain-training mightn’t be harmful, she says, but it is “a poor investment of your money”. “We’ve got to wait until we’ve got evidence that shows it does something different to what your everyday life already does.” In the meantime, there’s nothing wrong with reading a good book.