NEW YORK, Jan 04 (Reuters Health) -- Patients with mild forms of
Alzheimer's disease can usually still drive safely, with crash rates similar to
other older drivers, results of a small study suggest.
"Although road test studies have shown a clear decline in average driving
ability with increasing severity of dementia," note researchers at Washington
University in St. Louis, Missouri, "some drivers are still judged to be safe who
are in the very mild or mild stages of the disease."
The researchers, led by Dr. David B. Carr, looked at the state motor
vehicle accident records of 34 patients with very mild dementia of the
Alzheimer's type, 29 with mild Alzheimer's disease, and 58 without dementia.
Participants had an average age of 77, and had been driving for at least 10
years.
All participants kept a driving journal for a week, completed a
questionnaire about their driving history, and took a road test as part of the
study. For each participant, another adult who knew him or her well also filled
out a questionnaire.
The researchers found that patients with mild Alzheimer's disease drove
less than the other two groups. Overall, crash rates were low for all three
groups, with 80% driving accident-free for 5 years. Writing in the January issue
of the Journal of the American Geriatrics Society, Carr and his team note that
most studies of demented drivers report more car crashes among this group. They
add that they would have needed at least 300 participants in their study to
identify differences among the groups, given the overall low number of crashes
these participants had.
On the other hand, the authors write that participants with dementia were
slightly more likely to have crashes in which they were at fault, and more that
were due to inattention or failure to yield. Carr's group calls for more
research with larger numbers of participants, especially looking for ways to
assess driving competence.
In an editorial in the same issue, Dr. Richard A. Marottoli of the VA
Connecticut Healthcare System in West Haven, notes that clearer guidelines need
to be developed for physician reporting of patients whose dementia may impair
their driving. Marottoli concludes that we need a system that can "determine
which individuals are truly at increased risk" for causing traffic accidents.
