Because cognitive impairment might pose a safety risk for these drivers and
the public, we examined what patient characteristics might be associated w
ith motor vehicle crashes, in a retrospective study of all new referrals to
a geriatric clinic specializing in memory and behavior problems between Ju
ly 1, 1990 and June 30, 1995. During this time, 989 new patients were evalu
ated by the clinic staff. Driving data were available from 634 patients. Th
e only factor significantly associated with crashes was driving alone (odds
ratio = 2.23, 95% confidence interval = 1.20-4.15). Twenty-five percent of
patients who drove alone had caregiver-reported crashes in the previous 5
years, compared with 13% of those who drove only with a passenger. Patients
who drove alone were more likely to have spousal caregivers than patients
who drove only with a passenger (72% vs. 58%, p = 0.028). Thus, cognitively
impaired patients allowed to drive alone were more likely to have been inv
olved in crashes than patients not driving alone. However, the causal natur
e of this association cannot be established with the present design. Prospe
ctive studies are required to determine if the presence of a co-pilot repre
sents a safe strategy to extend driving privileges in cognitively impaired
older drivers.