Abstracts

Rationale: EEG background abnormalities are reliable predictors of MRI abnormalities and neurodevelopmental outcomes in neonatal hypoxic-ischemic encephalopathy (HIE). Seizure Burden in neonatal HIE is proportional to the severity of the encephalopathy and MRI injury. However, a correlation with quantitative analysis of early EEG and subsequent seizure burden in neonatal HIE has not been studied.Methods: EEG [1-20 Hz] power in the C3-P3 and C4-P4 channels of continuous EEGs was calculated in the first hour of recording in infants with HIE undergoing TH admitted to St. Louis Children's Hospital between Jan 2009 and March 2011. Visual analysis of the raw EEG was done to exclude epochs with artifacts and seizures. Total EEG power (TEP) was then calculated by averaging power from both channels. The TEP was compared between infants with and without seizures. TEP was also compared between infants with and without significant seizure burden (greater than 30 minutes).Results: 50 infants with HIE were enrolled for an EEG monitoring study, of which 42 underwent therapeutic hypothermia. Artifact free EEG data was available in 31 infants in the first 24 hours. EEG data from these 29 term infants was analyzed. 11 infants had seizures ( average seizure duration 112 minutes), of which 8 had a high seizure burden of more than 30 minutes. The TEP in the first hour of recording was significantly higher in neonates without seizures as compared to those with seizures (p=0.037). The TEP was also significantly lower in infants with a high seizure burden as compared to others with none or low seizure burden ( p = 0.018).Conclusions: EEG power (TEP [1-20 Hz]) in the first hour of recording is capable of predicting seizures and high seizure burden in infants with hypoxic ischemic encephalopathy undergoing hypothermia. This information could be useful in stratifying infants to study prophylactic anti-seizure medications in neonatal hypoxic ischemic encephalopathy.