EEG findings in cooled asphyxiated newborns and correlation with site and severity of brain damage

OBJECTIVE: EEG and MRI are useful tools to evaluate the severity of brain damage and to provide prognostic indications in asphyxiated neonates. Aim of our study is to analyze the relationship between serial neonatal EEGs and severity and sites of brain lesions on MRI in neonates undergoing hypothermia, following a hypoxic-ischemic injury. PATIENTS AND METHODS: Forty-eight term newborns underwent hypothermia. Serial videoEEG recordings were taken at 6, 24, 48 and 72 h and during 2nd week of life. Brain MRI was performed at the end of 2nd postnatal week and correlated with EEG. RESULTS: EEGs improved during the first days. At the first recording 25 infants showed a severe or very low amplitude EEG pattern while at the 2nd week only 7 showed such patterns. As regards MRI, 21 infants showed a predominant Basal Ganglia and Thalami damage, 4 infants showed a predominant focal Thalami lesion and 23 showed normal imaging or just mild White Matter abnormalities. Severity of EEG pattern was associated with the odds of having MRI lesions at Basal Ganglia, Thalami, White Matter, Internal Capsule, but not at Cortex. Infants who showed only mild EEG abnormalities in the first 2 days had no Basal Ganglia and Thalami MRI lesion. The persistence of a discontinuous EEG at the 2nd week recording is always associated with Basal Ganglia and Thalami damage. CONCLUSION: The severity of EEG background is associated with severity and site of MRI lesion pattern in neonates treated with hypothermia because of hypoxic-ischemic encephalopathy.