THURSDAY, Jan. 24, 2008 (HealthDay News) -- People with early Alzheimer's disease were involved in more traffic crashes and performed worse on road tests than drivers without cognitive impairment, a new study finds.
The findings, by researchers at Rhode Island Hospital and Brown University, confirm previous reports of potentially hazardous driving by people with early Alzheimer's disease (AD). But the study also shows that some people with mild dementia are able to continue driving safely for extended periods of time.
The study included 84 people with early Alzheimer's and a control group of 44 age-matched people without cognitive impairment. Over two to three years, the participants' driving abilities were assessed through self-reports, family reports and a standardized road test.
People with Alzheimer's disease were involved in more crashes and had worse results on road tests than those in the control group. The study also found that people with mild dementia were much more likely to fail a road test than those with very mild dementia.
"Our findings showed that people with mild dementia were almost four times more likely to fail a road test than those with very mild dementia, indicating that people with very mild dementia may be able to drive safely for longer periods of time," principal investigator Dr. Brian Ott, director of the Alzheimer's Disease and Memory Disorders Center at Rhode Island Hospital, said in a prepared statement.
"It is clear, however, that driving ability declines fairly rapidly among patients with dementia, and therefore, regular follow-up assessments are warranted in these people with very mild dementia," added Ott, a professor at Brown University Medical School.
The findings were published in the Jan. 23 issue of the journal Neurology.
People with very mild dementia who continue to drive should be re-assessed every six months, the American Academy of Neurology Guideline on Risk of Driving and Alzheimer's Disease recommends.
Interestingly, the frequency of crashes involving those with Alzheimer's declined during the study.
Overall, the study results "suggest that a regular driving assessment program may actually reduce the frequency of motor vehicle accidents in drivers with mild dementia by increasing awareness among drivers and caregivers. This, however, may also result in premature termination of driving privileges for some persons with dementia," Ott said.
Ott and his colleagues also found that driving abilities could be affected by age as well as education levels. For each year after age 75, the odds of failing a road test increased by about 6 percent. And the risk of failing a road test increased 10 percent for each year a person lagged behind the average 14 years of education.
More information
The Alzheimer's Association has more about Alzheimer's and driving.
