Factors predisposing patients with temporal lobe epilepsy to seizure cluster

Background: We aimed to identify the potential risk factors associated with seizure clusters in patients with temporal lobe epilepsy (TLE). Methods: This retrospective cross-sectional study was performed on all the consecutive patients with TLE, who were admitted to the Epilepsy Monitoring Unit (EMU), Loghman-Hakim Hospital, Tehran, Iran. Seizure cluster was defined as three or more habitual seizures occurring within 24 hours, in over 50% of ictal events, with inter-seizure interval of less than 8 hours. The patients' demographic data, epilepsy duration, seizure frequency, frequency of interictal epileptiform discharges (IEDs), and brain magnetic resonance imaging (MRI) findings were collected. Results: Among a total number of 124 patients with TLE, 62 (50.0%) patients reported seizure clusters. In addition, 44 (37.9%), 42 (36.2%), and 30 (25.9%) patients had normal-appearing brain MRI, mesial temporal sclerosis (MTS), and other brain pathologies, respectively. In terms of IEDs frequency, 35 (29.4%), 43 (36.1%), 17 (14.3%), and 24 (20.2%) patients had respectively frequent, occasional, rare, and no spikes in one-hour of interictal scalp electroencephalography (EEG) recording. In our study, seizure clusters were not associated with the epilepsy duration (P = 0.100), the amount of IEDs (P = 0.764), or MRI findings (P = 0.112). Conclusion: In patients with TLE, seizure clustering had no correlation with the epilepsy duration, the amount of IEDs, or brain MRI findings.