Changes in performance over time on the Bayley Scales of Infant Development II when administered to infants at high risk of developmental disabilities.

PURPOSE: The purpose of this study was to analyze changes in performance over time on the Bayley Scales of Infant Development II (BSID-II) in a sample of infants at high risk of developmental disabilities.
METHODS: Cognitive and motor performance of 53 infants, 34 with prenatal drug exposure (DE group) and 19 with perinatal medical concerns (PMC group), was measured at under one year of age (mean = 6.99 months) and again at 17-22 months of age (mean = 18.24 months). Changes in performance on both the Mental and Motor Scales over time were analyzed.
RESULTS: Over time, cognitive performance decreased for both groups (p < 0.05). Rate of change in motor performance increased for the PMC group and decreased for the DE group (p < 0.01).
CONCLUSIONS: Developmental changes over time should be studied separately for infants prenatally exposed to drugs and infants with perinatal medical concerns. Longer term follow-up with several repeat assessments would be desirable.