Alzheimer's disease and driving
If you know someone who has Alzheimer’s disease and he or she is still driving, it may be time to test their driving skills. As the number of people with Alzheimer’s disease and other forms of dementia grows, the driving ability of these affected individuals comes into question. Several recent studies looked at this dilemma.
Researchers at the University of Iowa recently evaluated 40 drivers who had been diagnosed with early Alzheimer’s disease and 115 elderly drivers who did not have the disease. Both groups of subjects participated in a combination of off-road tests that measured thinking, movement, and visual skills, as well as a 35-mile driving test in and outside the city.
The researchers found that the drivers who had Alzheimer’s disease made an average of 42 safety errors on the test drive, 27 percent more than those committed by the people with Alzheimer’s, who made an average of 33 mistakes. Lane violations were the most common mistakes. The researchers also found that for every five years older the participant was in either group, the number of driving errors made increased by about two and a half.
In a test conducted in 2008, researchers evaluated the driving abilities of people with early Alzheimer’s disease using self-reports, family reports, and a standardized road test. A total of 128 people participated: 84 with early Alzheimer’s disease and 44 age-matched individuals without cognitive impairments. The people with Alzheimer’s were followed every six months over two to three years.
People with early Alzheimer’s had more accidents and performed more poorly on road tests than people without cognitive impairments. The study also showed that the odds of failing a road test increased by about six percent for every year a person was older than age 75. People who had mild dementia were four times more likely to fail a road test than those who had very mild dementia. This finding suggests that people who have very mild dementia may be able to drive safely for longer periods of time.
Because driving ability declines quite rapidly among people who have Alzheimer’s disease, regular and often follow-up assessments are necessary. The American Academy of Neurology recommends that drivers who have very mild dementia should be reassessed every six months. Caregivers should discuss their concerns with the patient’s physician and check with their state laws concerning retesting of older drivers. Currently six states have laws that require physicians to report patients who have conditions that make driving dangerous.
Sources: Dawson JD et al. Neurology 2009 Feb 10; 72(6): 521-27.
Ott BR et al. Neurology 2008 Apr 1; 70(14): 1171-78.