COGNITIVE CAPACITY AND CONCURRENT DRIVING PERFORMANCE IN OLDER DRIVERS

One essential question in the issue of older driver safety involves assessment of driving skills. The present study addressed this question and, more specifically, the evaluation of change in drivers' cognitive ability and how this impacts driver safety. One hundred twenty-three subjects were evaluated by means of detailed laboratory and on-road driving evaluations. Ninety-one subjects were volunteers and reflected the general driving population over age 55. Thirty-two subjects had probable Alzheimer-type dementia and were referred by specialty clinics. A series of computer-administered cognitive tests were found to correlate significantly with driving performance. Most of the same measures were correlated with age. Among these, a type of selective visual attention (useful field of view) emerged as the best single predictor of driving performance. Other indices of driving difficulty included driver reports of low annual mileage, and drivers' receipt of a recommendation (from anyone) to stop driving. The oldest drivers more frequently failed to meet road-test driving standards, drove fewer annual miles, and used more compensatory strategies. The potential usefulness of single or combined cognitive screening measures is presented, along with a discussion of the relative merits of function versus age-based evaluation.