Accuracy of the Bayley-II mental development index at 2 years as a predictor of cognitive impairment at school age among children born extremely preterm

J Perinatol. 2018 Jul;38(7):908-916. doi: 10.1038/s41372-017-0020-8. Epub 2018 May 29.


Objective: To describe the accuracy of the Bayley Scales of Infant Development-Second Edition (BSID-II) Mental Development Index (MDI) at 2 years of age for prediction of cognitive function at school age of children born extremely preterm.

Design: Study participants were enrolled in the Extremely Low Gestational Age Newborn Study between 2002 and 2004. Two-thirds of surviving children (n = 795) were assessed at 2 years with the BSID-II and at 10 years with an intelligence quotient (IQ) test. We computed test characteristics for a low MDI (<70), including predictive value positive.

Results: Almost two-thirds of children with a low MDI had a normal IQ (≥ 70) at 10 years. Concordance between MDI and IQ was highest among children with major motor and/or sensory impairment, and when MDI was adjusted for gestational age.

Conclusion: Most children born extremely preterm with low BSID-II MDI at 2 years have normal intelligence at school age.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Child Development / physiology
  • Child, Preschool
  • Cognition
  • Cognitive Dysfunction / epidemiology*
  • Cohort Studies
  • Developmental Disabilities / diagnosis*
  • Developmental Disabilities / epidemiology
  • Developmental Disabilities / etiology
  • Female
  • Gestational Age
  • Humans
  • Infant
  • Infant Mortality / trends*
  • Infant, Extremely Premature*
  • Infant, Newborn
  • Intensive Care Units, Neonatal
  • Male
  • Neuropsychological Tests*
  • Prognosis
  • Retrospective Studies
  • Risk Assessment
  • Sex Factors
  • Survivors
  • United States