Bayley‐4 performance of very young children with autism, developmental delay, and language impairment.

Early identification of autism spectrum disorder (ASD) provides the best opportunity for children to receive evidence‐based early intervention. Research indicates that accurate diagnosis can be made as early as the toddler period when an assessment is completed by experienced clinicians. Typical ASD evaluations involve an assessment of developmental skills, such as those measured with the Bayley Scales of Infant and Toddler Development, Fourth Edition. There is limited research, however, on the use of the newest iteration, the Bayley‐4, in discriminating between various developmental disorders and delays. This study compared the performance of three groups of toddlers on the Bayley‐4: (1) ASD (n = 31), (2) developmental delay (n = 26) and (3) problems specific to language (n = 45). Results of a multivariate analysis of variance indicated mean differences existed between the ASD and language groups on the five Bayley‐4 subtests that comprise the Cognitive Motor, and Language Scales; however, logistic regression analysis indicated group membership could not be predicted by performance on the subtests. Our findings suggest children who are identified with ASD at a very young age exhibit global developmental deficits, which may help distinguish them from other groups who exhibit more targeted delays. Key Points: The Bayley‐4 subtests are sensitive to the weak areas of functioning in children with autism spectrum disorder, developmental delay, and problems specific to language. When attempting to distinguish between various neurodevelopmental disorders in very young children, school psychologists must assess all areas of developmental functioning. [ABSTRACT FROM AUTHOR]