Cognitive performance in a low birth weight cohort at 5 and 11 years of age

The objective of this study was to evaluate cognitive functions, changes over time, and prenatal, perinatal, and neonatal predictors in low birth weight children. A cohort of 130 low birth weight children was compared with 131 control children. A neuropsychologic test battery including subtests from the Wechsler Intelligence Scale for Children-Revised and the Illinois Test of Psycholinguistic Abilities, Knox Cube Test, Grooved Pegboard Test, Finger, and Foot Tapping was used. School performance was assessed using the Child Behavior Check List. Low birth weight children were comparable with control children in areas of verbal and visuo-spatial function, distractibility, and motor tempo, when parental factors were controlled for. An apparent association between breast milk feeding and child intelligence quotient was rendered insignificant when confounding parental factors were controlled for. None of the other identifiable prenatal, perinatal, or neonatal predictors were significantly related to cognitive outcome or school problems at 11 years of age. No differences were found in cognitive functions between those weighing less than 1500 g and 1500-2000 g. Motor problems and low verbal intelligence quotient at 5 years of age in the low birth weight children (previously published data) each doubled the risk of presenting a school problem at 11 years of age. Our findings are encouraging for low birth weight children regarding testable cognitive consequences and less encouraging regarding ability of cognitive test to identify school problems.