Using adaptive behavior scores to convey level of functioning in children with autism spectrum disorder: Evidence from the Study to Explore Early Development
Authors: Furnier Sarah M , Ellis Weismer Susan , Rubenstein Eric , Gangnon Ronald , Rosenberg Steven , Nadler Cy , Wiggins Lisa D , Durkin Maureen S 
Published: August 2023

We examined relationships between measures of adaptive behavior, cognitive ability, and autism symptom severity in 1458 preschool-aged children with autism from the Study to Explore Early Development. While publications commonly describe autistic children as “low-” or “high-functioning” based on cognitive ability, relying solely on cognitive scores may obscure meaningful variation in functioning. We found significant heterogeneity in adaptive behavior scores of children with cognitive scores both above and below the threshold of two or more standard deviations below the population mean specified in the diagnostic criteria for intellectual disability (ID). Although cognitive and adaptive behavior scores were strongly associated in our sample, considerable variation in overall adaptive behavior and more than half in socialization and motor skills was unaccounted for by cognitive ability, autism symptom severity, and other covariates. Among children who could be designated “low-functioning” based on cognitive scores, 39.7% had composite adaptive behavior scores indicating no significant delays, while among those who might be designated “high-functioning,” 9.0% had significant delays in overall adaptive behavior and 22.2% in socialization. These results suggest adaptive behavior scores capture variations in the autism phenotype not accounted for by other measures we considered. Lay Abstract Autistic people are often described as “low-” or “high-functioning” based on their scores on cognitive tests. These terms are common in publications and in everyday communication. However, recent research and feedback from the autistic community suggests that relying on cognitive ability alone to describe functioning may miss meaningful differences in the abilities of autistic children and adults and in the kinds of support they may need. Additional methods are needed to describe “functioning” in autistic children. We examined whether scores from a test measuring adaptive behaviors would provide information on the functional abilities of children with autism that is different from cognitive ability and autism symptom severity. Adaptive behaviors include age-appropriate skills that allow people to function in their everyday lives and social interactions. We found that a large amount of the variation in adaptive behavior scores was not explained by cognitive development, autism symptom severity, and behavioral and emotional problems. In addition, there was a wide range of adaptive ability levels in children with autism in our study, including in those with low, average, or high cognitive scores. Our results suggest that adaptive behavior scores could provide useful information about the strengths and support needs of autistic children above and beyond measures of cognitive ability and autism symptom severity. Adaptive behavior scores provide important information on the needs of autistic people.