Fig. 1. Wechsler Preschool and Primary Scale of Intelligence score measures at 4 and 8 yr after surgical repair of complex congenital heart defects. Population norms are 100 ± 10. There were no significant differences between the study groups and the population norms. Data compiled from Bellinger et al. 21,22,and de Ferranti et al. 23 WISC-III = Wechsler Intelligence Scale for Children–III.