FRIDAY, Sept. 17 (HealthDayNews) -- While some people with early-stage Alzheimer's disease can drive safely, regular assessments of their driving and memory are the best way to tell when it's time to take away the keys.
That's the conclusion of a study by University of Iowa researchers that appears in the Sept. 14 issue of Neurology.
"Drivers with early Alzheimer's can drive rather well, particularly in situations where the driver is familiar with the route or close to home," said study author Dr. Matthew Rizzo, a neurologist with the University of Iowa.
The researchers set out to determine whether those with mild Alzheimer's disease (AD) were safe behind the wheel. They recruited 32 people who had been diagnosed with the disease. Through a series of cognitive and memory tests, the researchers confirmed the people scored only slightly lower than the general population, thus identifying them as early-stage patients. The study also included a control group of 136 people with no neurological disorders.
Those with Alzheimer's disease were still driving, although some had cut back their driving due to self-imposed restrictions or to limits set by their families, the researchers said.
The study participants used cars outfitted with sensors, cameras and control devices to measure how the vehicles were handled. The 45-minute test included a portion in which the participants were asked to drive a predetermined course taking them through moderate traffic. They were given verbal directions before starting out, forcing them to navigate from memory.
Another portion of the test let the participants drive without having to remember and follow directions.
Those with early stage Alzheimer's disease drove as safely as the control group in straight segments of the drive and in situations where remembering directions wasn't necessary.
But safety dipped when those with mild Alzheimer's had to follow the memorized directions. More than 70 percent made driving errors such as wrong turns, compared to 20 percent from the control group. And nearly 70 percent of the drivers with Alzheimer's made safety errors such as erratic steering or driving on the shoulder of the road. This led the researchers to conclude that the mental demands of having to recall directions compromised driving abilities.
"Finding where you're going while driving a car kind of divides your mind. People tended to make more safety errors when their minds were occupied," said Rizzo. Twenty percent of the control group made similar safety errors.
When driving in easy conditions or in familiar areas, people with mild impairment can do just fine, Rizzo said. "If you're an experienced driver and have been doing it for years, it's not really that hard to navigate through low traffic, on straight roadways, and in good weather," he said. "But where the rubber meets the road -- when something else is happening where they have to pay attention -- this is when they tend to fail."
So what should family members or friends of early-stage Alzheimer's patients do about driving? Monitor the situation closely, experts say.
"It would be unfair to take away the license of everyone who has mild AD because they may actually be safe drivers and may self-restrict in situations where they are unsafe," said Rizzo. "On the other hand, there are some who can't. Those people need to be assessed because ultimately, AD can rob people of their judgment. It's not a bad idea to have a vigilant family member monitor driving, if one exists."
Dr. David Drachman, a neurologist at the University of Massachusetts Medical School who wrote a commentary about the study, agreed that on-road testing is the best way to measure a driver's competence. "If the driver with mild Alzheimer's is safe today, I recommend that a family member ride with him or her at least once a month, and if the observer feels endangered, the driver should no longer operate a vehicle," he said in a statement.
The Alzheimer's Association takes a similar position. In its 2003 position paper on Alzheimer's and driving, the association said a diagnosis of the disease isn't enough reason to revoke driving privileges. The group suggests that on-road assessments be done by trained personnel. Those with early-stage Alzheimer's are often aware of their diagnosis, as well as their abilities and limitations. And Alzheimer's patients should be involved in the decision to quit driving, when appropriate, according to the association.
To learn more about Alzheimer's disease, visit the Alzheimer's Association.