Prediction of on-road driving performance in patients with early Alzheimer's disease

OBJECTIVES: Physicians and family members frequently are asked to provide information about driving ability in patients with Alzheimer's disease (AD), yet there has been little research on the validity of their assessments of driving performance. DESIGN: Cross-sectional. SETTING: Participants were recruited from the neurology department of a community hospital affiliated with Brown Medical School. PARTICIPANTS: Participants included 75 older adults (17 with mild AD, 33 with very mild AD, and 25 elderly controls). MEASUREMENTS: The participant him/herself, an informant, and an experienced neurologist rated each participant's driving ability on a 3-point rating scale (safe, marginal, unsafe). A professional driving instructor also completed a standardized 108-point on-road driving assessment of each participant and then rated driving ability on the 3-point scale. Ratings were compared with the on-road driving score and with each other. RESULTS: Only the neurologist's rating of the participants' driving abilities was significantly related to on-road driving score. When related to the instructor's safety rating, the neurologist's ratings were the most sensitive and specific. Mini-Mental State Examination score was a borderline covariate for the neurologist's rating. Overall, the instructor was the most stringent rater of participant driving ability, followed by the neurologist, the informant, and the participant. CONCLUSION: An experienced neurologist's assessment of driving competence may be a valid predictor of driving performance of patients with early AD.