Seizure clusters in drug‐resistant focal epilepsy

We investigated clinical factors associated with seizure clustering in patients with drug‐resistant focal epilepsy and any association between seizure clustering and outcome after surgery. We performed a retrospective study including patients with a diagnosis of drug‐resistant focal epilepsy who underwent epilepsy surgery. Patients were prospectively registered in a database from 1986 until 2015. Seizure cluster was defined as two or more seizures occurring within 2 days. Potential risk factors for seizure clustering were assessed. To investigate any potential association between seizure clusters and seizure outcome after surgery, time to event analysis was used to produce a Kaplan‐Meier estimate of seizure recurrence. We studied 764 patients. Seizure clusters were reported in 23.6% of patients with temporal lobe epilepsy (TLE) and 16.9% of extratemporal patients (p = 0.2). We could not identify any significant clinical factors associated with seizure clustering. Among patients with TLE, those who had history of seizure clusters fared better after surgery (p < 0.01). We found that seizure clusters relate to prognosis after temporal lobe surgery in drug‐resistant TLE. These data may provide added value for surgical prognostication when combined with other data types. A better understanding of the neurobiology underlying seizure clusters is needed.