The theory is simple; the more marbles you have, the more you can afford to lose. It is why so many seniors do crossword puzzles and Sudoku or play computer games designed to boost brain fitness in an effort to stay sharp and protect themselves against Alzheimer's disease.
But researchers are still trying to figure out if the strategy works. They are assessing games that are on the market and developing new, more specialized ones they hope will delay the onset of dementia in people who are already experiencing memory loss.
Brain-fitness software and games are growing in popularity, but so far there is little evidence that many of the products go beyond helping people improve the specific skills they practice.
An arithmetic game may boost math skills, but not help memory, says Robin Hsiung, a dementia researcher at the University of British Columbia. And a memory game may help someone remember more words on a list, but not the name of someone they just met.
A more general improvement in brain fitness is what's required to help people with mild cognitive impairment, Dr. Hsiung says.
He asked 20 volunteers with memory problems to play Nintendo's Brain Age game every day for three months. They have been diagnosed with mild cognitive impairment, which can progress into dementia, and Dr. Hsiung wants to see if a game designed to boost brain power by solving math problems and other exercises, will improve their scores on a range of tests. He will compare them to a control group of healthy volunteers, before and after the three months of Nintendo.
Wheat from chaff
At the University of California in San Francisco, neuroscientist Adam Gazzaley has found that, as we age, we are less able to filter out irrelevant information and distractions, which slows the brain's ability to process.
He has developed a computer game to strengthen that skill by testing a person's driving ability, forcing players to navigate a twisty road while paying attention to some signs along the way and ignoring others. The hope is that this kind of reinforcement will translate into improved memory, and Dr. Gazzaley has started a trial with 90 older adults.
Also in San Francisco, a company called Posit Science produces software that aims to boost overall brain function, including memory, by improving on how accurately and quickly people process the sounds and sights their ears and eyes bring in. Clinical trials have shown it can help healthy, aging individuals improve their memories and driving skills, says Henry Mahncke, vice-president of research and outcomes.
Posit's programs - some of which are available in free demos online - are among those being tested by Columbia University's Jimmy Choi, although his hypothesis is that a combination of brain training, physical exercise and volunteer work will produce a more significant improvement than any program using computer games alone.
None of the games is designed for pre-Alzheimer patients. They are for healthy individuals who want to avoid the normal declines in cognitive function associated with aging. The hope that they may help to stave off Alzheimer's comes from the many studies that have shown that the more formal education people have, the less likely they are to get the disease.
Scientists call this "cognitive reserve," the idea that the more fuel you have in the tank, the more you can afford to lose. As well as doing crossword puzzles, many seniors try to top up their tanks by taking music lessons and doing other activities that require brain power.
But nothing like this is on a par with earning a university degree, Dr. Choi says, and there is no proof that it has a tangible impact on Alzheimer's. A recent study found that the disease develops later in people who do crossword puzzles or other mental exercises - but progresses more rapidly once it sets in.
At Baycrest's Kunin-Lunenfeld Applied Research Unit in Toronto, Nicole Anderson is focusing on what's known as source memory, the context in which information was learned.
"Who told you something? In which newspaper did you read something?" she explains. "It is the kind of memory most affected by aging and dementia, the ability to relive an experience in all its contextual richness."
Seeing vs. Hearing
Dr. Anderson has developed a training program that even healthy volunteers find difficult. They sit at a computer, and a long series of words either appear on the screen or are broadcast through the speakers. When the word comes up on the computer again, they have to specify whether they saw it or heard it the first time.
She is training eight volunteers with mild cognitive impairment and eight more as part of a control group. They all practice the task for an hour a day.
The sample size is small because the study also involves brain imaging, which is expensive and time-consuming. As well as better memory, Dr. Anderson wants to see if the training improves any other brain activity.
Another Baycrest researcher, psychologist Kelly Murphy, operates a less high-tech program designed to teach people with mild cognitive impairment and their families how diet, exercise and leisure activities may slow the rate of decline.
The people with MCI also are taught memory exercises to help in their daily lives. One trick, called "spaced repetition," has them try to remember the name of someone they've just met by saying it to themselves a few times, and then attempting to recall it at increasingly longer intervals.
Another tactic, called "logical location," allows people to keep track of such essentials as their keys and wallet by making sure they're always left in the same place.
By helping people keep doing such things as get dressed on their own, the program may delay the descent to full dementia.
Dr. Choi says it is important to remember that the goal is to help patients get more out of the time they have left, not simply to boost their score on a memory test a few points by playing hours of computer games.
"Even if brain-fitness programs can improve their memory," he asks, "can it improve it enough to justify the person spending hours and hours away from their loved ones? ... In the end, it's really about helping someone improve their quality of life."
Anne McIlroy writes on the science of the brain for The Globe and Mail.