Abstracts

Rationale: Persons with epilepsy may have seizures that impact safe driving, and up to 40% of patients with recurrent seizures continue driving. The challenge is to determine if and when driving is adequately safe. The gold standard on-road evaluation is not feasible due to cost, access, capacity of driving evaluators and potential danger from uncontrolled seizures. Therefore, our objective is to determine which tests from a clinical battery are correlated with errors made during simulated driving using a DriveSafety DS-250r simulator, for future predictions of driving performance.Methods: This study is exploratory, nested into an experimental pre and post design approved by the University of Florida s Institutional Review Board. A convenience sample of seven drivers (out of twenty expected) with epilepsy was recruited from an in-patient Epilepsy Monitoring Unit. Each subject completed vision, visual-cognitive, cognitive, and motor tests from a clinical battery. After simulator acclimation, each subject drove one or more thirty-five minute drives. The outcome variables were type and frequency of driving errors (i.e., visual scanning, lane maintenance, speed regulation, signaling, yielding, adjustment to stimuli and gap acceptance) based on evaluator observation. We used a two-tailed Spearman Rank Correlation Coefficient to examine the relationships among the clinical tests (i.e., visual acuity, Useful Field of View, Trails B and foot tap). Results: For the seven drivers, mean age = 40.0 SD +10.1, 60% female, 86% white, mean years education 12.3 SD +0.5. Spearman Rank (Table 1) showed significant correlations for: visual acuity with visual scanning errors (r =.91, p<.01) and total errors (r= .81, p<.05); Useful Field of View subtests 2 and 3 with visual scanning errors (r =.99, p<.01 and r=.94, p<.01 respectively) and total driving errors (r=.93, p<.01 and r=.96, p<.01 respectively); and contrast sensitivity with total errors (r = -.79, p<.05).Conclusions: These preliminary findings indicate correlations of visual and visual cognitive tests with simulated driving, yet require further testing.