Characteristics of Young Children Associated with Diagnostic Utility of the Autism Diagnostic Observation Schedule: A DBPNet Study.

Objective: The aim of this study is to identify characteristics of children for whom a developmental-behavioral pediatrician's (DBP) diagnostic impressions of autism spectrum disorder (ASD) or non-ASD were changed by Autism Diagnostic Observation Schedule (ADOS) results.

Method: A prospective study of children 1½ to <6 years consecutively referred to 8 sites for possible ASD. Cognitive/developmental, language, and adaptive testing varied, as each site followed its usual clinical approach. DBPs documented diagnosis as ASD or non-ASD and their degree of diagnostic certainty (1-10) pre- and post-ADOS. Cases where DBP diagnostic impression did not change after ADOS administration ("Stable Group," n = 314) were compared with those for whom it did change ("Changed Group," n = 35), followed by matched random sample comparisons.

Results: There were no significant differences in child characteristics (age, gender, race, ethnicity, insurance, caregiver education) between the Stable and Changed groups. DBPs' diagnostic certainty was significantly lower, both pre- and post-ADOS, in the Changed versus Stable group. Change was associated with milder symptoms of ASD and less impaired language. In an age- and gender-matched comparison, significant differences remained for diagnostic certainty and severity of social communication impairments. Cognitive scores were significantly higher in the Changed Group. Because of significantly higher caregiver education and a trend toward more privately insured children among the Changed Group, samples (n = 35 each) were then matched on those characteristics, revealing the same differences for diagnostic certainty, severity of ASD symptoms, and language skills.

Conclusion: Young children with milder ASD symptoms and less impaired language may benefit most from the administration of the ADOS.