Abstracts

Rationale: Restrictions to driving due to a diagnosis of epilepsy can have profound impacts on the quality of life of people with epilepsy. The ability to lead independent lives, to work, and to maintain social ties is significantly hampered by loss of a driving license. In most parts of the world, driving privilege is dependent on people with epilepsy demonstrating a seizure free interval, the length of which depends on local legislation. Physicians are often called on to make judgments on whether a patient is capable of having a safe presence on the road. However, there are limited data available in the literature, consisting mainly of retrospective studies based on analysis of crash databases and people with epilepsy s self-report of motor vehicle crashes. There is a need for prospective studies objectively measuring driving ability during seizures.Methods: Telemetry data during seizures and baseline was captured from a driving simulator used by patients during hospital stays for continuous video/EEG monitoring. 32 clinical seizures were analyzed during driving in 19 patients. Ictal driving performance was compared to baseline driving performance data during interictal periods. Quantitative criteria were used to determine the presence or absence of impairment before, during and after seizures. These criteria included car velocity, steering wheel movement, application of the brake pedal, and occurrence of crashes in order to determine impairment. Results: We found that there was a higher rate of crashes during seizures than driving on the same portions of the track during inter-ictal periods. Most seizures during driving were partial seizures (n= 23) and there were fewer absence (n = 7) and generalized tonic-clonic seizures (n= 2). We found that longer duration partial seizures were associated with more severe driving impairment. In addition, we find that subclinical seizures were not related to obvious impairment in driving using the same metrics as for the clinical seizures.Conclusions: Our results demonstrate that prospective testing of ictal driving is feasible during inpatient video/EEG monitoring. Impairments in driving during seizures can be related to the duration of partial seizures and whether seizures were clinical or subclinical. We hope in future work to determine whether seizure type and localization can be related in greater detail to different levels of driving risk. Further analysis could also reveal whether subclinical events cause more subtle impairments. Such information would be valuable to physicians, regulators, and patients, in helping to determine the ability of people with epilepsy to drive safely.