Using electroencephalography (EEG) for diagnosing subsequent epilepsy in children after febrile seizure (FS) is not common. The present study investigates the relationship between epileptiform discharges and subsequent epilepsy, and looks for the predictive marker for this disorder. A total of 378 children with complex FS and whose EEG showed epileptiform discharges or normal EEG were included. Development of FS was compared between those with epileptiform discharges and those with normal EEG. Risk factors were analyzed using multivariate logistic regression to clarify their effects on subsequent epilepsy. The association between generalized or focal EEG localization, and between frontal epileptiform discharges and subsequent epilepsy, were analyzed. Among 378 patients with complex FS, 51 showed epileptiform discharges. History of epilepsy, frontal seizure, number of FS, and prolonged seizure were the risk factors for epileptiform discharge. Subsequent epilepsy was significantly frequent in patients with more than 2 risk factors (odds ratio [OR] = 17; 95% confidence interval [CI] = 4.1-29.6). Prolonged seizure (OR = 4.98; 95% CI = 1.63-13.29), FS number (OR = 2.96; 95% CI = 1.23-10.51), and family history of epilepsy (OR = 2.67; 95% CI = 1.05-7.63) were significantly correlated with subsequent epilepsy. Of 9 patients with paroxysms in the frontal region, 8 (88.9%) developed epilepsy. There was concordance between frontal epileptiform discharges and subsequent epilepsy (κ = .901). In conclusion, epileptiform discharges are risk factors for subsequent epilepsy. Frontal paroxysmal EEG is a marker for subsequent epilepsy.
Keywords: electroencephalography; epilepsy; epileptiform discharges; febrile seizure; frontal paroxysmal.
© EEG and Clinical Neuroscience Society (ECNS) 2014.