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-III^UK) 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.