Cognitive Outcomes After Neonatal Encephalopathy

Abstract

Cognitive impairment is an important issue found in survivors at 18 to 24 months in all major previous trials of hypothermia treatment of hypoxic ischemic encephalopathy (HIE). The authors of this study hypothesized that infants between 18 and 22 months with a Mental Developmental Index of less than 70 would continue to have cognitive impairment and development disabilities at school age. The study aimed to report special educational services and therapies, describe the range of cognitive outcomes of moderate or severe HIE in children, and evaluate the value of various predictors of school-age cognition. Data from the National Institute for Child Health and Development Neonatal Research Network multicenter trial of whole-body hypothermia, conducted between 2000 and 2003, were used in this secondary analysis. Participants who experienced moderate and severe encephalopathy within the first 6 hours of life were treated with either hypothermia or routine neonatal intensive care. Follow-up was at 18 to 22 months and 6 to 7 years and included neurologic examinations, the Bayley Scales of Infant Development, Wechsler intelligence scales, and Neuropsychological Assessment-Developmental NEuroPSYchological Assessment (NEPSY). Cerebral palsy severity was identified using the Gross Motor Function Classification System. Of 140 surviving children, 30 were lost to follow-up. Twenty-two percent of children were found to be untestable with the NEPSY because of severe cognitive and/or neurologic impairment. In children with cerebral palsy (CP), 96% (22/23) had an IQ of less than 70, and in children without CP, 9% had an IQ of less than 70, and 31% had an IQ score between 70 and 84. In children with Mental Development Index scores of less than 70, a wide range of gross motor outcomes was seen, with only 17% exhibiting fine motor skills. In children with an IQ of less than 70 at 6 to 7 years, only 23% had a normal gait, 6% to 16% of that group had normal complex motor functions, and about 10% had intact coordination and fine motor skills. Of the 110 children, 79 stayed in the same development range between 18 to 22 months and 6 to 7 years. Of the children followed up to 6 or 7 years, 7% to 9% had behavioral problems, compared with 5% to 7% among normally developing children, and 30% received special educational services. Children with neonatal encephalopathy were more likely to have special educational needs. The neuropathology of neonatal encephalopathy may be better understood with careful neurodevelopmental follow-up along with advanced neuroimaging, and this may provide new intervention opportunities. The study shows that while cognitive impairment is not specific to neonatal encephalopathy, it remains an important concern for survivors of neonatal encephalopathy. Whether motor impairment is present, school-age assessments and early intervention are recommended