Abstracts

Confirmation of neonatal seizure is frequently difficult without EEG because neonatal seizure is quite different from other epileptic seizures in many aspects including seizure semiology, electrographic finding and long-term prognosis. We investigated to determine the prognosis and risk factors of postneonatal epilepstic seizure in the newborns that have neonatal seizures. We retrospectively examined 71 infants who had neonatal seizures confirmed by EEG seizure with duration more than 10 seconds in regular EEG. Among 52 survivors, we examined the clinical and electrographic variables of 35 infants who were followed for more than 18 months. We divided these infants into two groups with postneonatal epileptic seizure and without postneonatal epileptic seizure. Postneonatal epileptic seizure developed in 43% (group A, 15 of 35). There was no postneonatal epileptic seizure in 67% (group B, 20 of 35). Among clinical variables, conceptional age at EEG seizures was older in A group (42.0 [plusmn] 4.4 weeks) than that of group B (39.4 [plusmn] 3.7 week) (P = 0.036). There was no significant difference in sex, gestational age, chronologic age at first seizure, Apgar score at 1 and 5 minutes, and the number of drugs administrated to control the neonatal seizure between two groups. Among EEG variables, abnormal EEG background and the duration of electrographic seizure affect the occurrence of postneonatal epileptic seizure. Abnormal EEG background activity occurred in group A (67%, 10 of 15) more often than in group B (35%, 7/20) with a tendency (P = 0.063). The duration of EEG seizure tended to be longer in group A (124 [plusmn] 224 seconds) than in group B (43 [plusmn] 52 seconds) (P=0.063). Number of EEG seizures, number of seizure onset zone and predominant frequency of EEG seizure were not significantly different between two groups. Developmental delay was noticed at the follow up in 77% (27 of 35). All the infants in group A showed developmental delay (15 of 15), while 40 % of group B showed normal development (8 of 20) (P=0.005). Our results suggest that older conceptional age at neonatal seizure, abnormal EEG background activity and the longer duration of EEG seizure predict postneonatal epileptic seizures. Infant who have both neonatal EEG seizures and postneonatal epileptic seizures have a high risk of developmental delay.