Abstracts

Rationale: The objective of this study was to compare information yielded by EEG and brain MRI imaging measures in infants with hypoxic ischemic encephalopathy (HIE) who received head cooling (HC) vs. whole body cooling (WBC) interventions. Methods: Eighty-two infants were identified with HIE in a multicenter retrospective study. Forty-one infants in this cohort who met inclusion criteria for therapeutic cooling received either HC (n=22) or WBC (n=19). All but one received an EEG (either continuous 24 hour or 1 hour) and 36 of 41 were scanned with a brain MRI during their course of treatment. A standardized scoring system, developed in prior studies for interpreting EEG [1] and brain MRI images [2, 3], was employed. EEG categories consisted of: (1) burst suppression/extremely low voltage, (2) depressed and undifferentiated, (3) excessive discontinuous, and (4) normal. Brain MRI categories included: (1) basal ganglia?"thalamus pattern; (2) watershed or subcortical white matter pattern; (3) perinatal arterial ischemic stroke (PAIS), perinatal hemorrhagic stroke (PHS), and sinovenous thrombosis; and (4) normal. Lower scores (on a scale ranging from 1 to 4) indicated more extensive injury. (see image 1,2). EEGs were read by a neonatal epileptologist. MRI images were read by a neuroradiologist. Readers were blind as to whether infants received HC or WBC interventions. Results: There were no significant differences between the two groups in Apgar scores, gestational age, HIE etiology, and neurological status upon examination. EEGs were abnormal in nearly all (97.5%) of hypothermic infants. There was no significant difference between the number of EEG abnormalities in the HC group (97%) and the WBC group (100%) p= 0.257. Brain MRIs were abnormal in little more than half (60%) of hypothermic infants. Abnormalities were more frequent in the HC group (57%) than in the WBC group (52%) p = 0.954. These brain changes were more severe in the HC group (36%) than in the WBC group (22%) p = 0.658. Conclusions: EEGs were more sensitive indicators of cerebral abnormalities in infants with HIE than were brain MRIs (i.e., generating 97.5 % vs. 60% abnormal readings). Amongst those with abnormal brain MRIs, cerebral changes were more frequent and more severe in the HC than in the WBC group. As nearly all infants exhibited abnormal EEGs, differences were not observed across HC and WBC groups on this measure. References: 1. Nash KB, Bonifacio SL, Glass HC, et al. Video-EEG monitoring in newborns with hypoxic-ischemic encephalopathy treated with hypothermia. Neurology. 2011; 76: 556-62. 2. de Vries LS and Groenendaal F. Patterns of neonatal hypoxic-ischaemic brain injury. Neuroradiology. 2010; 52: 555-66. 3. Sarkar S, Donn SM, Bapuraj JR, Bhagat I and Barks JD. Distribution and severity of hypoxic-ischaemic lesions on brain MRI following therapeutic cooling: selective head versus whole body cooling. Archives of disease in childhood Fetal and neonatal edition. 2012; 97: F335-9. Funding: None