First-ever seizure and eligibility for commercial motor vehicle driving

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.

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.

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.

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.