An array of new research findings is showing how a rich mental life, and potentially a specific type of brain exercise, may act as bulwarks against the onset of dementia.
The results are being presented this week at the Alzheimer's Association International Conference, the world's largest gathering of researchers in the field that kicked off in Toronto on Sunday.
Among the most intriguing data to emerge at the meeting are those coming from a long-running and randomized controlled experiment called the ACTIVE study, which, for the first time, appears to show that a particular form of brain training may confer a level of protection from dementia as subjects age.
The idea is a controversial one because of the proliferation of computer-based "brain games" whose claimed effectiveness against cognitive decline is generally not supported by the scientific literature.
But Jerri Edwards, the University of South Florida researcher who presented the result, said that a task specifically tailored to boost mental processing speed appears to have a lasting effect.
"The idea is that you improve a very basic ability and that is going to have broader transfer," she said.
As part of the study, roughly 700 healthy participants, averaging 74 years of age when the experiment began, received 10 hours of training on a computer task. Some received an additional four hours of training one to three years later. The task, which is commercially marketed as BrainHQ, requires participants to attend to the icon of a vehicle at the centre of the screen while also responding to various objects that pop up on the periphery.
After 10 years, 33 per cent fewer of those who received the initial training developed dementia compared with a control group who received no training. Among those who received the additional training, 48 per cent fewer developed dementia.
In contrast, other groups in the ACTIVE study that received other forms of cognitive training related to memory and reasoning skills showed no increased resilience to Alzheimer's.
Other results presented at the meeting suggest that a rich mental life, including a stimulating work environment and plenty of interaction with others, can act as a cognitive buffer and even counteract the effects of diet, a known risk factor for dementia.
Matthew Parrott, a postdoctoral researcher in nutrition science with Baycrest Health Sciences in Toronto, tracked 351 independently living older adults over a three-year period. He found that those who adhered to a typical "Western" diet that included processed meat, white bread, potatoes and prepackaged foods and sweets were more likely to experience cognitive decline. But that negative effect did not show up for those subjects whose backgrounds included at least two of three indicators: a high level of education, a complex occupation and a significant amount of social engagement.
"Your whole lifetime of mental experiences is going to change the way your brain is wired up," Dr. Parrott said, adding that later life experiences, including socially rich leisure activities, can contribute to cognitive resilience after retirement.
In another study, a group based at the University of Wisconsin's Alzheimer's Disease Research Center in Madison found that even among people with complex jobs, those that primarily worked with people rather than data or things were better able to cope with the damage to brain tissue associated with the disease.
According to recent estimates, 1.4 million Canadians are expected to be living with Alzheimer's disease by 2031, a steep rise that is mirrored in other developed countries as populations age. With the mechanisms behind the disease still unclear and with treatments largely focused on symptoms rather than causes, research related to Alzheimer's prevention is burgeoning.
Following a massive review of the literature, the Alzheimer's Association last year produced a list called "10 Way To Love Your Brain" to highlight preventative measures.
"You can keep your brain healthy and potentially stave off dementia or at least push it down the road a little if you're doing something active to increase your cognitive reserve," said Keith Fargo, director of scientific programs and outreach for the Chicago-based association.