When is it safe to return to driving following first-ever seizure?

OBJECTIVES The risk of recurrence following a first-ever seizure is 40-50%, warranting driving restriction during the early period of highest risk. This restriction must be balanced against the occupational, educational and social limitations that result from patients being ineligible to drive. The recommended duration of non-driving after a first seizure varies widely between jurisdictions, influenced by various factors including the community perception of an acceptable relative level of risk for an accident (the accident risk ratio; ARR). Driving restrictions may be based on individualised risk assessments or across-the-board guidelines, but these approaches both require accurate data on the risk of seizure recurrence. METHODS 1386 patients with first-ever seizure were prospectively analysed. Seizure recurrence was evaluated using survival analysis. The duration of non-driving required for a range of risks of seizure recurrence and ARRs was calculated. Additionally, the actual occurrence of seizures while driving was prospectively determined during follow-up. RESULTS For a risk of seizure recurrence to fall to 2.5% per month, corresponding to a monthly risk of a seizure while driving of 1.04 per thousand and an ARR of 2.6, non-driving periods of 8 months are required for unprovoked first-ever seizure, and 5 months for provoked first-ever seizure. Of patients with a seizure recurrence, 14 (2%) occurred while driving, with the monthly risk falling to less than 1/1000 after 6 months. CONCLUSIONS Our data provide a quantitative approach to decisions regarding a return to driving in patients with first-ever provoked or unprovoked seizure.