Reduced Hippocampal Volumes in Children with History of Hypoxic Ischemic Encephalopathy after Therapeutic Hypothermia.

Hypoxic ischemic encephalopathy (HIE) remains a significant cause of disability despite treatment with therapeutic hypothermia (TH). Many survive with more subtle deficits that affect daily functioning and school performance. We have previously shown an early indication of hippocampal changes in infants with HIE despite TH. The aim of this study was to evaluate the hippocampal volume via MRI and memory function at 5 years of age. A cohort of children followed from birth returned for a 5-year follow-up (n = 10 HIE treated with TH, n = 8 healthy controls). The children underwent brain MRI and neurodevelopmental testing to assess their brain volume, general development, and memory function. Children with HIE had smaller hippocampal volumes than the controls despite no differences in the total brain volume (p = 0.02). Children with HIE generally scored within the average range on developmental testing. Though there was no difference in the memory scores between these groups, there was a positive within-group correlation between the hippocampal volume and memory scores in children with HIE (sentence recall r = 0.66, p = 0.038). There was no relationship between newborn memory function and 5-year hippocampal size. Children with HIE treated with TH experienced significant and lasting changes to the hippocampus despite improvements in survival and severe disability. Future studies should target diminishing injury to the hippocampus to improve overall outcomes.

Preserved speed of processing and memory in infants with a history of moderate neonatal encephalopathy treated with therapeutic hypothermia.

OBJECTIVE: Survivors of neonatal encephalopathy (NE) are at risk for impaired cognition. The objective of this study was to assess speed of processing (SOP) and memory in infants with moderate NE. STUDY DESIGN: Sample consisted of 17 infants with NE and 23 healthy controls. Visual-evoked potentials (VEP) were assessed at 8 months to assess SOP. Memory was assessed at 12 months using elicited imitation (EI). Memory and SOP had previously been assessed in this cohort in the newborn period. RESULTS: Infants with NE had similar SOP and EI performance as controls. Newborn SOP correlated with 8-month SOP in infants with NE, however, neonatal ERP memory measures were not correlated with EI performance at 12 months. CONCLUSIONS: Infants with moderate NE treated with TH show preserved memory and SOP through 12 months. Early behavioral and electrophysiologic assessments of memory and SOP provide insight into developing cognitive functions in this risk group.