Mild dementia may not preclude driving

By Joene Hendry
11 april 2008 -- Many people with early Alzheimer's disease or mild dementia may initially be able to drive safely. However, "their driving skills predictably decline over 1 to 2 years to a level that often precludes safe driving," according to Dr. Brian R. Ott of the Alzheimer's Disease and Memory Disorders Center at Rhode Island Hospital, in Providence.
Red flags that indicate it's time to take away the keys include driving too slowly, being confused or undecided at intersections, getting lost in familiar locations, failing to observe traffic signs and signals, and, being in an at-fault motor vehicle accident, Ott told Reuters Health
Regardless of signs of cognitive impairment, "vigilance and reassessment of driving competence should be considered for all older drivers," Ott and his colleagues advise in the medical journal Neurology.
The researchers studied changes for up to 3 years in the driving ability of 84 individuals, about 76 years old, who had been diagnosed with very mild or mild Alzheimer's disease and of 44 individuals free of cognitive impairment but of similar age (controls).
The Alzheimer's subjects were evaluated clinically and had a driving test with a professional driving instructor every 6 months. The control group was tested when they were enrolled and after 18 months. The researchers also collected driving and traffic violation information on all participants over the course of the study.
Initially, 41 percent of the participants with early Alzheimer's disease were judged to be safe drivers, 44 percent were marginal, and 15 percent were deemed unsafe drivers.
By contrast, baseline driving tests showed 80 percent of controls as safe, 20 percent as marginal and none as unsafe.
By 18 months, many of the participants in both groups had stopped driving either due to hazardous driving or progression of dementia. At this point, just 5 of the 26 Alzheimer's patients who could still be evaluated tested safe (19 percent), compared with 12 of the 21 control-group drivers (57 percent).
These findings highlight the need for valid screening tests of cognition and driving skill that can identify any at-risk driver who should have a specialized driving evaluation, Ott said.
SOURCE: Neurology, April 2008