Electroencephalogram confirmatory rate in neonatal seizures

The electroencephalogram (EEG) is confirmatory in 70% of children and adult s with seizures, although gestation- and etiology-specific EEG confirmatory rates in neonates have not been well defined. All neonates treated for sei zures and who underwent EEG were identified from 4,575 neonates admitted be tween 1985 and 1996 to a neonatal intensive care unit. The relationship bet ween EEG findings (epileptiform discharges and background abnormalities) an d gestation, mortality rate, and seizure etiology was examined using the St udent t test. One hundred eighty-three neonates treated for seizures underw ent a total of 352 EEGs: 144 of these neonates (79%) had an abnormal EEG (e pileptiform discharges in 113 (60%) and non-epileptiform background abnorma lities in 31). The EEG confirmatory rate increased with gestation (63% at 2 8 weeks vs 77% at term, P < 0.02). Etiology for seizures also influenced th e EEG confirmatory rate: central nervous system (CNS) infection 95% (P < 0. 05), hypoxic-ischemic encephalopathy 80% (P < 0.05), germinal matrix-intrav entricular hemorrhage 65%, and CNS malformations 65%. The EEG confirmatory rate was predictive of neonatal mortality (19% vs 6%, P < 0.03). The EEG wa s directly confirmatory (epileptiform discharges) in 60% and supportive (no n-epileptiform background abnormalities) in a further 17% of neonates with seizures. Gestation and etiology influence the EEG confirmatory rate in neo natal seizures. (C) 1999 by Elsevier Science Inc. All rights reserved.