Alzheimer's disease-(AD), a progressive neuro-degenerative disorder characterized by memory, visuospatial, problem-solving, and communicative disabilities, accounts for 50-60% of all dementia patients. As the disease progresses, these changes become more prominent and may be accompanied by motor problems. Although it is often assumed that such impairments interfere with safe driving, to date no systematic study of the importance of these changes in relation to driving ability has been made. The proposed study is a longitudinal, prospective study of 80 patients with AD and 80 age and sex matched controls to determine: 1) if performance on visual, oculomotor, and neuropsychological tests predict driving performance as assessed on a driving simulator; 2) if a task analysis of specific safe-driving behaviors during a simulated on-the-road driving test can be used to identify individuals who are at increased risk for automobile accidents; and 3) whether declines in performance on visual, oculomotor, and neuropsychological tests in AD patients can be used prospectively to predict cessation of driving, changes in driving habits, and increased risk of accidents or moving violations. Data on visual, oculomotor, and neuropsychological tests, and on driving performance and threat recognition as assessed on a driving simulator, will be collected at recruitment and at 12 and 24 months following recruitment for both AD patients and controls. In addition, these data will be collected at just one point in time for a separate group of 20 AD patients with more advanced disease. A questionnaire will be used to collect data on driving patterns, accidents, and violations at each data collection visit. Driving records will be obtained from the Motor Vehicle Administration at recruitment and after 24 months. Data will be reduced using factor-analytic approaches and analyzed to after identify which factors are the best predictors of driving skills. The performance of the AD patients will be compared to that of the controls, both in general, and after adjusting for disease-related changes in the AD patients. Analyses will be carried out to identify compensatory mechanisms used by elderly drivers and AD patients as their vision and neuropsychological functions change. The predictive value of possible screening approaches for elderly, and especially AD individuals, will be calculated.