For a good decade now, John Morris, M.D., a professor of neurology
at Washington University in St. Louis, has been interested in the impact of
Alzheimer's disease on a person's ability to drive.
This issue is becoming increasingly important, Morris reported at the
annual Canadian Psychiatric Association meeting in Vancouver in November,
since the baby-boom population is growing older, and by 2020 there is going to
be a huge number of people 65 years or older driving. And the older people
get, the more susceptible they become to Alzheimer's or other forms of
Indeed, simply growing older in itself can be a risk factor for motor
vehicle accidents, Morris noted. In one study he and his colleagues conducted,
they found that some cognitively healthy older adults became unsafe drivers
over a period of two years. But older adults with Alzheimer's declined even
more in their driving over this time span, the study showed. The smallest
decline in driving occurred in the older, cognitively healthy control
subjects, the second-smallest decline in those with very mild Alzheimer's, and
the greatest decline in those with mild Alzheimer's.
Of course, 16- to 24-year-olds are the most dangerous drivers on the road,
Morris said. "But many people with dementia continue to be drivers, and
all of them will become unsafe at some point."
Common unsafe behaviors in which such individuals engage, he continued,
include inability to maintain the vehicle within the lane, failure to signal
directional changes or lane shifts, and improper speed control.
Nonetheless, he pointed out, simply having a diagnosis of dementia does not
necessarily mean that a person is an unsafe driver. So the question is, When
should older people with dementia be told that they can no longer drive?
Physicians caring for such individuals, he asserted, need to get involved.
One possible means of determining whether dementia patients should no
longer drive is cognitive evaluation, Morris said. Putting them in a driving
simulator is better, but unfortunately it is only a research tool at this
point. Still another option is having an occupational therapist give the
patient a driving test. Yet such a test is expensive and not widely
Another option is to talk not only with dementia patients, but with a
family member who knows them well and how well they are driving in order to
determine whether they should continue driving. "Physician judgment
turns out to be pretty good," Morris said.
Another motivation for physicians' becoming involved in the question of
whether dementia patients should stop driving, Morris pointed out, is that
adult children of patients with dementia are often reluctant to make the
"It is a very sensitive issue," he said. Driving is the way
that Americans and Canadians generally get about, and if older people can not
go out, they often get depressed. ▪