Driving errors seen in early Alzheimer's disease

Even mild Alzheimer's disease may interfere with some seniors' ability to follow basic driving instructions, according to study findings released Monday.

In comparison to people without the Alzheimer's disease, affected seniors were more likely to make incorrect turns, to get lost and to steer erratically or make other such safety errors, researchers report.

Alzheimer's disease currently affects one in ten Americans over the age of 65, and nearly one out of every two individuals over the age of 85. The condition is known to eventually impair seniors' safe driving ability, but the mental deterioration is gradual, so it may be difficult to recognize the point at which people with Alzheimer's disease (AD) should stop driving.

"Currently, there are no firmly established criteria to predict driver safety in Alzheimer's disease," Dr. Ergun Y. Uc of the University of Iowa told Reuters Health.

"Our study is part of our project to scientifically address this question," he added. "At this time, seniors with AD and their families should discuss this issue openly with their physician, undergo neuropsychologic and vision testing as needed, and comply with retesting requirements with the DOTs of their state."

To assess driving ability and safe driving practices, Uc and his colleagues conducted a battery of mental and visual tests among 32 seniors with mild Alzheimer's disease and had them participate in a route-following exercise.

For the 45-minute driving exercise, seniors used a mid-sized station wagon equipped with hidden miniature cameras and other sensors that monitored their control of the car's speed, their driving lane, steering wheel position and other safety-related information. For comparison the study also included 136 seniors without any type of dementia.

The two groups were similarly able to maintain control of the automobile, with regard to the position of the steering wheel, number of lane changes and other aspects of basic vehicular control, the report indicates.

Yet in the driving exercise, seniors with Alzheimer's disease were more likely than those without the condition to turn too quickly, too late, or in the wrong direction, to get lost and to make safety errors, the majority of which included illegally crossing lane boundaries, the researchers report in the September 14 issue of Neurology.

"Even rather mild AD patients navigate poorly and commit safety errors," Uc said.

Drivers familiar with the area in which the route-test was taken, however, did not get lost. Also, the researchers note, some drivers with Alzheimer's disease were able to follow the driving instructions correctly and safely.

This suggests "that some individuals with mild dementia remain fit drivers and should be allowed to continue to drive," the authors write.