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

Background: Neurodevelopmental difficulties in children following hypoxic-ischaemic encephalopathy (HIE) may not emerge until school age. Aims: To evaluate the value and stability of early serial developmental assessments in predicting long-term outcome. Study design: Prospective study of infants with neonatal HIE and early continuous EEG at birth. Subjects: Term infants with HIE were recruited at birth. Development was measured at 6, 12 and 24 months using the Revised Griffiths' Scales (GMDS-R). Outcome measures: Intellectual 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. Results: IQ 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 24 months 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 5 years (24 month AUROC value = 0.941, p = 0.001). An abnormal early GDQ score at any stage in the first 24 months had excellent negative predictive values, superior to those for neonatal Sarnat and EEG grading. Conclusions: Normal early development predicts normal 5 year 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.