Developmental evaluation of very-low-birthweight infants: Longitudinal and cross-sectional studies

The cognitive development of 83 children of very-low-birthweight (VLBW; birthweight less than or equal to 1500 grams), ages three to seven years, was evaluated in longitudinal and cross-sectional studies on the McCarthy Scales of Children's Abilities. In the longitudinal study, head circumference had the strongest association with cognitive scores. Other factors related to cognitive scores included neurological complications during hospitalisation in the neonatal intensive care unit (NICU), the child's age at the present investigation, and mother's level of education. In the cross-sectional study, the VLBW children were compared with control groups of children from middle class families (MC) and lower class families (LC) The VLBW group scored significantly lower than the MC group on all the McCarthy scales, but did not differ from the LC group. When level of mother's education was partialled out, group differences remained significant, except for the perceptual-performance scale. Evaluation of the increase in VLBW children's raw scores on the subtests, from age three to seven, demonstrated that VLBW advanced significantly less than the MC children in Word Knowledge, Conceptual Grouping, and Numerical Memory Backwards. Furthermore, the gap between the scores of VLBW and MC children increased over time. These results demonstrate that VLBW children with normal levels of IQ score significantly lower than the MC group on many cognitive tasks, and that on some of these the gap increased over age.