title: Relationship between test scores using the second and third editions of the Bayley Scales in extremely preterm children.
abstract: OBJECTIVE
  To define the relationship between current Bayley Scales of Infant and Toddler Development, Third edition (Bayley-III) scores and the Bayley Scales of Infant Development, second edition Mental Development Index (MDI) to aid the comparison of population outcomes.
  
  
  METHODS
  MDI and Bayley-III cognitive/language scales were administered concurrently in 185 extremely preterm children (≤26 weeks) at 29-41 months of age. Cognitive and language scores were combined (combined Bayley-III score [CB-III scores]) for comparison with MDI scores.
  
  
  RESULTS
  Bayley-III cognitive and language scores were 10 and 3 points higher than MDI scores, respectively; CB-III scores were 7 points higher. The relationship between CB-III and MDI scores was not a simple offset: CB-III values were increasingly higher than MDI at lower scores. Bayley-III scores underidentified MDI scores <70 (sensitivity 58%; specificity 100%). An algorithm for converting Bayley-III scores into MDI scores improved predictive value (sensitivity 95%; specificity 97%). Bayley-III scores <80 were similarly predictive (sensitivity 89%; specificity 99%).
  
  
  CONCLUSIONS
  We recommend caution in the interpretation of Bayley-III scores in population studies as the correlation with the previous edition appears worse at lower test score values and the predictive value for IQ is as yet unclear.
authors: Research Department of Academic Neonatology, UCL Institute for Women's Health, University College London, London, UK.
authors: Tamanna
authors: T
authors: Moore
authors: Samantha
authors: S
authors: Johnson
authors: Sadia
authors: S
authors: Haider
authors: Enid
authors: E
authors: Hennessy
authors: Neil
authors: N
authors: Marlow
mesh_terms: D002675:Child, Preschool; D003071:Cognition; D002658:Developmental Disabilities / Q000175:diagnosis*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000175:diagnosis*; D007804:Language Development; D009483:Neuropsychological Tests