The ability of early serial developmental assessment to predict outcome at 5 years following neonatal hypoxic-ischaemic encephalopathy

Abstract

BackgroundNeurodevelopmental difficulties in children following hypoxic-ischaemic encephalopathy (HIE) may not emerge until school age. AimsTo evaluate the value and stability of early serial developmental assessments in predicting long-term outcome. Study designProspective study of infants with neonatal HIE and early continuous EEG at birth. SubjectsTerm infants with HIE were recruited at birth. Development was measured at 6, 12 and 24months using the Revised Griffiths' Scales (GMDS-R). Outcome measuresIntellectual abilities at age five were measured using the Wechsler Preschool & Primary Scale of Intelligence (WPPSI-IIIUK) and the ‘numbers’ subtest from the Children's Memory Scale. Overall five-year outcome was also reported. ResultsIQ outcome was available in forty-seven surviving children (28 male, 19 female: mean (SD) age 64.0(5.7) months. Mean processing speed (p=0.01) and short-term verbal memory (p=0.005) were below the norm. Global development (GDQ) at 6, 12 and 24months correlated (p<0.01) with five-year global, verbal and performance IQ with improved correlation over time. Normal GDQ throughout early childhood predicted normal IQ at 5years (24month AUROC value=0.941, p=0.001). An abnormal early GDQ score at any stage in the first 24months had excellent negative predictive values, superior to those for neonatal Sarnat and EEG grading. ConclusionsNormal early development predicts normal 5year IQ with prediction increasing over time. Repeated measurement is warranted due to instability of findings across the first two years. Follow-up for children with abnormal early development is warranted given high sensitivity for school-age global abnormal outcome.