Identifying driving impairment in Alzheimer disease: a comparison of self and observer reports versus driving evaluation.

This study examined the relationship between driving behaviors and awareness of deficit in patients with Alzheimer's disease (AD). Fifteen mildly impaired AD patients and 15 healthy elderly controls with valid drivers' licenses were administered a series of questionnaires concerning daily functioning and driving performance, and all 30 subjects were evaluated on a standardized road test. Self-report and caregiver/informant responses were compared with determine levels of discrepancy in ratings, while comparisons of AD and healthy elderly controls revealed group differences. Actual driving performance was considered the standard by which to determine accuracy of perceptions. Drivers with AD were rated as significantly worse than healthy elderly drivers on nine of 10 driving behaviors by an independent evaluator. AD patients' self-reports of driving ability were significantly better than the evaluator's ratings on seven of the 10 items, whereas the healthy elderly drivers rated themselves better than did the evaluator on one item. Although caregivers were likely to acknowledge a general concern with their AD patients' driving, they underreported specific driving problems when their ratings were compared with those of an independent evaluator. These findings have implications for the development of caregiver-based modifications of driving behavior.