Associations between clinical tests and simulated driving performance in persons with epilepsy

People with epilepsy (PWE) may experience seizures that constitute a risk to road safety. Consequently, many states have instituted restrictions, such as being seizure-free for intervals of 3 to 12 months, before driving can be resumed. However, 30% of drivers with recurrent seizures still drive despite having a restricted license. As a result of recurrent and uncontrolled seizures, PWE may have impairments in motor, visual and cognitive abilities, as well as impaired driving performance. No studies to date have prospectively examined factors associated with driving performance in PWE. The primary objective of this study was to determine which tests, from a clinical battery, are correlated with driving errors in PWE using a simulator. The sample consisted of 16 drivers with epilepsy (mean age 44.3 +/- 12.0; 63% women) recruited from the epilepsy monitoring unit at the University of Florida. All participants completed a clinical battery of cognitive, visual and motor tests, as well as a 35-minute drive on a simulator. Significant correlations emerged between: visual acuity with visual scanning (r=.69, pb<.01) and adjustment to stimuli (r=.60, pb<.05); contrast sensitivity with lane maintenance (r=-.54, p>.05), vehicle position (r=-.61, p>.05) and total number of errors (r=-.72, p>.01); and useful field of view scores (subtest 2) with visual scanning (r=.57, p>.05) and vehicle position (r=.63, p>.05). Limitations and future implications are addressed. The preliminary findings suggest visual and visual-cognitive tests are associated with driving errors in a simulated driving environment. (C) 2012 Elsevier Inc. All rights reserved.