Abstracts

Rationale: Current legislation places numerous driving restrictions on people with epilepsy to help minimize the risk of motor vehicle crashes. Antiepileptic drugs (AED) are often necessary to control seizures successfully. Despite their benefits, AEDs have side effects that may impact safe driving performance. Few studies focus on the effects of AED dosage on driving performance of people with seizures. Driving simulators offer a safe alternative to on-road driving evaluations, the industry standard, which may pose a crash risk. In this preliminary analysis, a driving simulator was used to evaluate effects of AED dosage on simulated driving performance. Methods: A convenience sample of participants with seizures (n= 4) was recruited from an Epilepsy Monitoring Unit to participate in a pre and post-test design. Eligible participants were given questionnaires and a battery of clinical tests to assess cognition, vision, motor, and sensory functioning. After the battery, participants drove acclimation scenarios, in a DriveSafety DS-250r simulator, followed by a 35-minute simulated drive to evaluate driving performance. A baseline drive of an individual s highest AED dosage was compared to an identical drive at their lowest dosage. We assessed performance on driving parameters of lane maintenance, adjustment to stimuli, speed regulation, and brake reaction time at the two time periods. Types and frequencies of errors are based on evaluator observations and recorded simulator data. Results: For lowest dosage AEDs compared to highest dosage AED drives, mean error frequency increased for variables of lane maintenance (3.5, SD+2.4 vs. 4.5, SD+4), adjustment to stimuli (.25, SD+5 vs. .5, SD+.6), and speed regulation (2.8, SD+1 vs. 4.0, SD+1.8). Brake reaction time improved on higher dosages (3.0, SD+1.4 vs. 2.3, SD+.8). The Wilcoxon signed rank test showed no significance for the errors between the two drives: lane maintenance (p = .46), adjustment to stimuli (p = .32), speed regulation (p = .10), and brake reaction time (p = .14).Conclusions: Our current findings are preliminary and inconclusive, yet are yielding an interesting pattern: that drivers on higher dosages of AEDs, at times required for control of seizures, exhibit more driving errors compared to when they are taking lower dosages, except for brake reaction time. We are continuing enrollment into this study and believe that our findings, upon study completion, will contribute to the current body of literature on impacts of AEDs on simulated driving performance.