Silent seizures in sick infants in early life. Diagnosis by continuous cerebral function monitoring.

Cerebral electric activity was surveilled with a Cerebral Function Monitor (CFM) technique in 87 newborn infants under neonatal intensive care. A total of 26 infants had electrographical signs of repeated seizure activity. Among these infants 14 had periods of one hour or more of silent seizures activity. Among these infants 14 had periods of one hour or more of silent seizures, i.e. typical pattern of ictal epileptic activity on CFM without clinical symptoms or signs of convulsions. The occurrence of silent seizures and their pattern in relation to the clinical condition and management was unpredictable in most cases. Besides general limpness or flaccidity in an outward quiet baby these infants showed no clinical fits or clonic convulsions. The findings indicate that anticonvulsive therapy in small infants may be insufficient and need re-evaluation, since the long-term effect of silent seizures on cerebral function and activity is still uncertain.