Alzheimer's Disease and Driving: Prediction and Assessment of Driving Performance

Abstract

OBJECTIVES : To examine driving competence in a group of drivers diagnosed with probable Alzheimer's Disease (AD) in terms of a standardized open road evaluation and expert judgments. To examine the validity of a standardized medical examination, including administration of the Mini‐Mental Status Exam (MMSE), and a standardized neuropsychological assessment as predictors of open road driving performance. DESIGN : A prospective investigation with consecutively referred subjects. SETTING : Coorabel Driver Assessment Centre, Royal Rehabilitation Centre Sydney, Australia. PARTICIPANTS : Nineteen subjects with a diagnosis of probable AD. MEASUREMENTS : A standardized clinical medical examination, a standardized neuropsychological assessment, and a standardized open road driving evaluation. The driving evaluation provided a correct driving actions score. The outcome measure was the expert judges' rating of overall driving competence, which was termed the final on‐road result. RESULTS : Seven subjects passed the on‐road driving evaluation, and 12 failed. MMSE was found to be a significant predictor of final on‐road result. The physician's prediction, the neuropsychology test scores, and the neuropsychologist's prediction were not found to be significantly associated with the final on‐road result. The on‐road driving evaluation was a reliable test. CONCLUSION : Inasmuch as all subjects except one were still driving and all wished to continue to drive, it is important to note that 63.2% of subjects failed the on‐road evaluation. Conversely, 36.8% were judged safe to drive, suggesting that AD diagnosis alone may be insufficient criteria for cessation of driving. A standardized road test may be the only appropriate means of determining driving competence in people diagnosed with AD.