Change in Cognitive Function over Time in Very Low-Birth-Weight Infants

Abstract

Context: Preterm very low-birth-weight (VLBW) infants have a high prevalence of neurodevelopmental disability when evaluated during the first several years of life. However, recent experimental data suggest that the developing brain may recover from or compensate for injury. Objective: To determine if there is cognitive improvement throughout early and middle childhood following VLBW birth. Design, Setting, and Participants: Follow-up data of 296 infants born weighing 600 to 1250 g who participated in a prospective, randomized, placebo-controlled intraventricular hemorrhage (IVH) prevention study performed at 3 northeastern US hospitals between September 1989 and August 1992 and who were serially evaluated at 36, 54, 72, and 96 months of corrected age (CA). Main Outcome Measures: The age-normed Peabody Picture Vocabulary Test-Revised (PPVT-R) score and measures of intelligence. Results: Overall, the median PPVT-R score increased from 88 at 36 months of CA to 99 at 96 months of CA; when data from 36 and 96 months of CA were compared, 45% of children gained 10 points or more and 12.5% showed a 5- to 9-point increase in test scores. Similar findings were noted for full-scale and verbal IQ scores. Multivariate analyses demonstrated that increasing age, residence in a 2-parent household, and higher levels of maternal education were all significantly associated with higher PPVT-R scores (for each, P