Imagine knowing if dementia will affect you simply by taking a walk.
Approximately 500,000 Canadians are currently living with Alzheimer’s disease or a related dementia. That number is expected to soar to 1.1 million within 25 years. While there is no definitive method to predict the onset of dementia, one Western researcher is providing a glimmer of hope.
Medicine, Epidemiology and Biostatistics professor Manuel Montero Odasso explores walking speed and variability as predictors of dementia’s progression, and whether they are associated with physical changes in the brain.
Funded by the Canadian Institutes of Health Research, the Gait and Brain Study was initiated in 2007 and has been following up to 200 seniors diagnosed with mild cognitive impairment, a pre-dementia syndrome, in order to detect an early predictor of cognitive and mobility decline, and progression to dementia.
“Subtle changes in gait, particularly in ability and symmetry, may predict symptoms leading to full dementia, as well as who is going to go faster to dementia,” said Montero Odasso.
While walking has long been considered an automatic motor task, emerging evidence suggests cognitive function plays a key role in the control of walking, avoidance of obstacles and maintenance of navigation.
“Sometimes walking is automatic; sometimes it is not,” Montero Odasso continued. “Think about it as crossing a busy Yonge Street in Toronto. There’s a red light, a streetcar is coming, people are riding bikes, there’s a lot of people. Walking is not automatic; you have to pay attention to everything. That is navigation.
“What we know is, the same brain areas that control navigation are the same brain areas that control cognition and memory. So the hippocampus, an area of the inner brain, is very important for navigation and memory.”
When you walk and talk, or walk and perform another task, it’s a stress test for the brain because you are using the same connections all the time, Montero Odasso said. When you share those connections, and your brain reserve is not as strong as before due to age, you begin to show problems with gait. You start slowing down.
In Montero Odasso’s lab, located at Parkwood Hospital, seniors with mild cognitive impairment walk on a specially designed mat linked to a computer, which records a number of variables related to the individual’s walking gait variability and speed. This is then compared to their walking gait while simultaneously performing a demanding cognitive task, such as counting backwards or doing calculations while walking.
“For everyone, when you’re walking and doing math, you’re going to slow down slightly. That’s normal,” Montero Odasso said. “But people with cognitive problems linked to dementia, the change is much more obvious and significant.”
These gait changes can predict cognitive decline and may eventually help with earlier diagnoses of dementia. Montero Odasso added the ideal window to intervene with some form of medication is when an individual may have mild memory loss, but still able to work, drive and complete daily activities without concern.
When we age, we all have some cognitive problems, he said. But they’re not all related to dementia. In fact, 30 per cent of people over 65 have memory problems, but will be fine the rest of their lives.
“We want to treat the others – those who are going toward dementia,” Montero Odasso said, adding it’s conceivable diagnoses of Alzheimer’s disease and other dementias will be made before people even have significant memory loss. “Over the years, there has been an increasing integration in how mobility and cognitive skills are studied. It is heading in a direction I am excited about.”