Which Bayley-III cut-off values should be used in different developmental levels?

Abstract

Background/aim: Latest version of Bayley Scales Bayley-III and its predecessor BSID-II are the most widely used standardized developmental tools in infancy and early childhood. Recent studies showed that Bayley-III scores were higher than BSID-II in 18-24 month-old and mostly premature infants. We aimed to evaluate the generalization of inflated scores of Bayley-III to children aged 6-42 months with different disease groups, and to find out which cut-off points should be used in Bayley-III to detect mild, moderate, and severe developmental delay according to BSID-II standard cut-off points. Materials and methods: Two hundred and fifty-five children aged 6-42 months with different diseases and developmental levels were administered both the Bayley-III and BSID-II in the same session between 15 November 2017 and 15 April 2018. Results: The mean Bayley-III Cognitive Composite CC and Cognitive Language Composite CLC scores were respectively 13.1 ± 9.1 and 8.6 ± 8 points higher than BSID-II Mental Development Index MDI scores P