Evaluation of Driving Ability in Older Drivers

ABSTRACT

OBJECTIVE: To assess the driving ability of older drivers, their visual function, cognitive-perceptual function, motor function and driving performance were evaluated. METHOD: Subjects were 55 drivers aged 65 years or older. Visual function test included visual acuity, visual field, color vision and contrast sensitivity. Cognitive perceptual function was evaluated with the cognitive perceptual assessment for driving (CPAD) and clock drawing test. For motor function, muscle strength and range of motion were evaluated. Driving performance was evaluated by virtual reality based driving simulator. For comparision, 48 younger drivers aged between late twenties and early forties underwent the same evaluation. RESULTS: Among older drivers, 21 (38.2%) had visual acuity less than 20/40, 3 (5.5%) had visual field narrower than 140degrees bilaterally. Contrast sensitivity was significantly decreased in both day and night with glare light conditions. In cognitive-perceptual function assessment, 20 subjects (36.4%) passed CPAD test, 3 subjects (5.5%) failed, and 32 subjects (58.1%) fell into borderline group. Mean CPAD score was 50.65+/-5.62, which was significantly lower than that of younger drivers. 18 subjects (32.7%) were incorrect in clock drawing test. In motor function assessment, 4 subjects (7.3%) in older drivers showed hemiparesis secondary to stroke. In driving simulator, 21 subjects (38.2%) failed whereas only 4 subjects (8.3%) did in younger drivers. Average demerit score was 24.09+/-15.53 and was significantly higher than that of younger drivers. CONCLUSION: Older drivers showed significantly higher incidence of visual and cognitive-perceptual dysfunction, and poorer driving performance compared to younger drivers group.