Do Bayley-III Composite Scores at 18-22 Months Corrected Age Predict Full-Scale IQ at 6-7 Years in Children Born Extremely Preterm?

Objective To determine the ability of the Bayley-III cognitive and language composite scores at 18-22 months corrected age to predict WISC-IV Full Scale IQ (FSIQ) at 6-7 years in infants born extremely preterm. Study design Children in this study were part of the Neuroimaging and Neurodevelopmental Outcome cohort, a secondary study to the SUPPORT trial and born 24(0/7)-27(6/7) weeks gestational age. Bayley-III cognitive and language scores and WISC-IV FSIQ were compared with pairwise Pearson correlation coefficients and adjusted for medical and socioeconomic variables using linear mixed effect regression models. Results Bayley-III cognitive (r = 0.33) and language scores (r = 0.44) were mildly correlated with WISC-IV FSIQ score. Of the children with Bayley-III cognitive scores of <70, 67% also had FSIQof <70. There was less consistency for children with Bayley-III scores in the 85-100 range; 43% had an FSIQ of <85 and 10% an FSIQ of <70. Among those with Bayley-III language scores >100, approximately 1 in 5 had an FSIQ of <85. A cut point of 92 for the cognitive composite score resulted in sensitivity (0.60), specificity (0.64). A cut point of 88 for the language composite score produced sensitivity (0.61), specificity (0.70). Conclusions Findings indicate the Bayley-III cognitive and language scores correlate with later IQ, but may fail to predict delay or misclassify children who are not delayed at school age. The Bayley-III can be a useful tool to help identify children born extremely preterm who have below average cognitive scores and may be at the greatest risk for ongoing cognitive difficulties.

Automated summary

The study found that the Bayley-III cognitive and language scores are correlated with later IQ, but may not accurately predict developmental delay in school-aged children or misclassify those who are not delayed. The Bayley-III can be a useful tool in identifying extremely preterm infants who may be at risk for cognitive difficulties.