Objective. To investigate the effects of biological and social factors on the cognitive development of very low birth weight children, a longitudinal follow-up study was conducted from birth to 3.6 years of age.
Methodology. The study group consisted of a cohort of 79 surviving high-risk, very low birth weight infants. Neonatal cerebral ultrasonographic findings and a neurological score were used as indicators of biological risk. A sociodemographic risk score and the Home Observation for Measurement of the Environment inventory were used as indicators of social risk. Cognitive development was assessed at ages 1 and 2 years by the Mental scale of the Bayley Scales of Infant Development and at age 3.6 years by the Kaufman Assessment Battery for Children.
Results. The mean mental index at 1 year of age was 96 (SD 19), at 2 years of age 86 (SD 26), and at 3.6 years of age for intelligence 87 (SD 13) and for achievement 86 (SD 14). In a stepwise multiple regression analysis of biological as well as social factors, the neurological score alone was the best predictor for cognitive development at 1 year of age, explaining 46% of the variance. From 2 years of age onward, the best predictors for cognitive development were the neurological score together with the home environment, explaining 46% of the variance for the Mental Developmental Index at age 2, 34% for intelligence, and 56% for achievement at age 3.6.
Conclusions. Children at high biological risk were able to catch up on their cognitive delay in a highly stimulating home environment. Children at low as well as high biological risk in a less stimulating home environment showed a decline in cognitive development. For these children, early intervention programs might be important in the prevention of cognitive disabilities.
- very low birth weight
- cognitive development
- neonatal cerebral ultrasonography
- sociodemographic risk
- home environment
- Received March 16, 1992.
- Accepted April 30, 1993.
- Copyright © 1993 by the American Academy of Pediatrics