First-ever seizure and eligibility for commercial motor vehicle driving.

Abstract

Background: After a first-ever seizure, 6 months of seizure freedom is usually required before returning to driving a private motor vehicle, after which the annual risk of seizure recurrence has fallen to ≤20%. Stricter criteria apply for commercial driver's licence (CDL) holders, and a longer period of seizure freedom sufficient for the annual risk of recurrence to be <2% is recommended. However, CDL guidelines are based on little data with few studies having long-term follow-up.

Methods: 1714 patients with first-ever seizures were prospectively studied. Seizure recurrence was evaluated using survival analysis. The annual conditional risk of seizure recurrence was calculated for patients with first-ever unprovoked and acute symptomatic seizures, and according to the presence or absence of clinical, electroencephalogram (EEG) and neuroimaging risk factors for recurrence.

Results: The annual risk of recurrence for unprovoked first seizures did not fall below 2% until after 9 years of seizure freedom. The annual risk after 5 years of seizure freedom was still 3.9% (95% CI 1.8% to 6.1%) including for those without epileptiform abnormalities on EEG and with normal imaging. For acute symptomatic first seizures, the annual recurrence risk was 4.5% (95% CI 2.3% to 6.7%) after 1 year and fell below 2% only after 4 years of seizure freedom.

Conclusions: For unprovoked and acute symptomatic first-ever seizure and CDL, a higher-than-expected annual seizure risk persists beyond the currently recommended seizure-free periods, even in those without risk factors for recurrence. Our data can inform decisions regarding a return to driving for CDL holders after first-ever seizure.