Factors associated with tonic-clonic seizures in patients with drug-resistant mesial temporal epilepsy.

PURPOSE Among different seizure types, tonic-clonic seizures are more significant because they are more often associated with morbidity. No prior study has been done to investigate risk factors associated with tonic-clonic seizures in patients with mesial temporal epilepsy. METHODS In this retrospective study, all drug-resistant mesial temporal epilepsy patients in the database of patients who underwent epilepsy surgery at Jefferson comprehensive epilepsy center were recruited. These patients were prospectively registered in a database from 1986 till 2014. Patients' age, gender, epilepsy risk factors, age at seizure onset, and preoperative seizure type(s) were registered routinely. Potential risk factors associated with experiencing preoperative tonic-clonic seizures were investigated. RESULTS Two hundred seventy-five patients (132 males and 143 females) were studied. Aura type was associated with experiencing perioperative tonic-clonic seizures. Patients with epigastric auras less frequently reported having tonic-clonic seizures compared with those who had other types of auras (odds ratio: 0.37 and 95% confidence interval: 0.19-0.70; p=0.001) and those who did not have any auras (odds ratio: 0.35 and 95% confidence interval: 0.16-0.77; p=0.008). CONCLUSION Epigastric auras may indicate that a specific anatomic location is involved in epileptogenesis from which generalization is harder because of that location's poor connections with other brain regions.