A decade ago, the American Academy of Neurology stated categorically that people with mild dementia pose a "significant traffic safety problem" when they are in the driver's seat.
But the medical body has now softened its stance. In new guidelines for doctors and caregivers, it suggests people with some degree of mental impairment may be able to drive reasonably safely.
"While patients with mild dementia, as a group, are higher-risk drivers, more recent studies report that as many as 76 per cent are still able to pass an on-road driving test and can safely drive," said the guidelines' lead author, Donald Iverson, a California-based physician.
"Faced with these facts, we need to provide guidelines for doctors caring for these patients to identify those at higher risk of unsafe driving without unnecessarily restricting those who are safe drivers."
The revised guidelines were released this week at the AAN's annual meeting, which took place in Toronto. The Canadian location for the gathering is somewhat fitting because the U.S. approach now more closely reflects the position already adopted by the Canadian Medical Association. In 2006, the CMA published driver-fitness recommendations that said not everyone with dementia needs to give up their car keys - at least not right away.
"Dementia is a generic term that covers a vast repertoire of limitations ... you can't stereotype," said Jamie Dow, a Quebec physician and an author of the CMA guidelines. "The type of limitation and the degree of limitation is going to be different for every single person. So you are going to have to sit down and look at each person as an individual."
The AAN guidelines provide a list of warning signs that may indicate a patient's driving skills are slipping. These "red flags" - such as recent collisions, numerous traffic tickets, or aggressive and impulsive behaviour - can help alert physicians and caregivers to a worsening condition.
But Dr. Dow noted that the best measure of driving ability is still a road test. "It is really hard to extrapolate from what you see in the [doctor's] office to performance behind the wheel."
According to the CMA, dementia patients who pass a provincial driving test should repeat the test every six to 12 months - or more, in cases of rapid cognitive decline.
The AAN approach also stresses the need for frequent road tests. "In almost all cases, there will come a point where driving has to cease as dementia progresses, and it is something that needs to be handled sensitively and prepared for in advance," Dr. Iverson said.