A first-of-its-kind study has examined the driving habits of more than 900 older drivers living across Canada, to determine how their cognitive abilities may impact their driving behaviour.
The research — published recently in the Canadian Journal on Aging — looked at people with dementia, mild cognitive impairment, subjective cognitive impairment (where a person thinks they are experiencing cognitive decline but there is no objective evidence that supports this), and no cognitive impairment.
Researchers found that most people who participated in the study had driver’s licences without restrictions. This included more than half of people with dementia, though these drivers were more likely than others to drive less often and drive shorter distances.
Women also were more likely to drive shorter distances and less often than men, across all the cognitive groups, the study found.
The findings are important, says the study’s senior author Jennifer Campos.
That’s because they may hold insights on how to support safe driving for older adults, as well as show how a person’s driving habits can be used to assess their cognitive function.
“One of the most complex activities we perform in our everyday lives is driving. When you drive, you must look, listen, think, plan and control your motor behaviours in a rapidly changing and dynamic environment,” says Campos, a professor at the Temerty Faculty of Medicine’s Rehabilitation Sciences Institute, and the Department of Psychology in the Faculty of Arts & Science.
“It’s an activity that has serious safety consequences.”
Campos says, for example, an older adult with subjective cognitive impairment may pass neuropsychological tests in a calm, controlled environment like a doctor’s office. However, that same person may have difficulty with a task like driving, because of the competing demands it requires of the brain.
The study found that of 241 older adults with dementia, about 41 per cent no longer had a valid license or chose to drive. Of those with dementia who no longer drove, 39 per cent said they stopped because a physician had advised them to. Another 33 per cent had voluntarily chosen to stop, says the study.
The research also found that women of all cognitive abilities were more likely stop driving voluntarily, while men were more likely to stop because of a doctor’s advice. It was also shown that drivers with dementia were just as likely to be the primary driver in their home, compared to other cognitive groups.
“It’s really interesting to examine how the driving habits of individuals who are at different stages of cognitive decline vary in terms of the distance they are driving, the frequency at which they’re driving, and their restrictions that they have either self-imposed or that have been imposed by others,” says Campos, who is also a senior scientist at University Health Network’s KITE Research Institute.
The study notes that not everyone who holds a licence may be driving.
“It is important to note that in many provinces a driver’s license is the only type of photo identification other than a passport. Therefore, some people retain an active driver’s license to serve as their primary photo identification without the intention to drive,” the researchers write in their paper.
Campos says an important element of the work is how it includes people with subjective cognitive impairment — a group of people at potential risk of developing clinically significant cognitive impairment in future.
Driving has a crucial role in many older adults’ lives, says Campos, and research can help illuminate the “intricate balance” needed between promoting road safety and maintaining independence and quality-of-life for older adults.
“When you are someone who depends on driving for independent mobility and are no longer able to drive, this can have a catastrophic effect,” she says.
Part of what is needed is better guidelines for medical professionals about when people should stop driving, she says.
“There are very few tools or tests that physicians can use to conclusively determine whether somebody with a possible neurodegenerative condition can safely drive,” says Campos. “This is a really, really hard decision to make until symptoms become very severe.”