Neonatal seizures in preterm infants: Clinical outcome and relationship with subsequent epilepsy

Objective: Neonatal seizures are considered an acute manifestation of disturbance of the neonatal brain. Some of them can be considered as neonatal epilepsy. Our goal was to evaluate perinatal risk factors, electroencephalogram (EEG) findings and ictal semeiological characteristics of our newborns with neonatal seizures in order to identify which clinical variables were the most early predictive factors of poor neurodevelopmental outcome and of epilepsy. Methods: Among all preterm infants consecutively admitted to the neonatal intensive care unit (NICU) of the University Hospital of Parma in the period between January 1999 and June 2003, 28 preterm infants with gestational age ≤ 36 weeks were selected according to the presence of repetitive neonatal seizures, need of chronic anticonvulsant therapy, more than one EEG performed during the neonatal period, and at least one imaging examination (cerebral ultrasound and/or cerebral magnetic resonance imaging (MRI). These patients were prospectively followed up for at least 6 months to evaluate the clinical outcome. Independent variables considered for analysis included perinatal risk factors, etiology of convulsions, EEG activity and type of seizures. Results: The background EEG activity was the strongest predictive factor of the neurodevelopmental outcome, but status epilepticus (SE) also represented a significant variable associated with poor prognosis and subsequent epilepsy. Conclusions: EEG activity was predictive of the developmental outcome and allowed identification of the infants with SE, a condition often related to neonatal epilepsy (71.4%, p < 0.05).