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.

The driving errors were probably due to the increased demands that the route exercise placed on the seniors’ memory, attention and perception, Uc and his team speculate.

In a related commentary, Dr. David A. Drachman of the University of Massachusetts Medical School discussed the difficulty of “assuring reasonably safe driving” among people with early Alzheimer’s disease.

He recommends that, if the patient’s driving ability is deemed safe by an experienced instructor, “a family member (should) ride with the patient at least once a month, and if the observer feels endangered, the driver should no longer operate a vehicle.”

Kathleen O’Brien of the Alzheimer’s Association told Reuters Health that she was not surprised with the study’s findings, that some seniors with Alzheimer’s disease did not perform well on the driving exercise.

In fact, she said, some people with Alzheimer’s disease choose to stop driving on their own, while some others have family members who remove the car’s distributor cap, file down their car keys or use other “creative solutions” to deter their loved one from getting behind the steering wheel.

O’Brien added that several chapters of the Alzheimer’s Association offer driving assessment clinics. To find out which states are included and other information about Alzheimer’s disease, contact the Alzheimer’s Association at 1-800-272-3900.

SOURCE: Neurology, September 14, 2004.