Using adaptive behavior scores to convey level of functioning in children with autism spectrum disorder: Evidence from the Study to Explore Early Development

Abstract

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.

Racial and ethnic disparities in the co‐occurrence of intellectual disability and autism: Impact of incorporating measures of adaptive functioning

“…In each racial and ethnic group, the VABS-II composite criterion resulted in larger reductions in the percentage classified with ID than the criterion requiring impairment in only one adaptive domain. These findings are consistent with past research documenting large discrepancies between IQ and adaptive scores in children with autism, with gaps sometimes exceeding one or even two SDs and adaptive scores often exceeding cognitive scores among children with IQ scores within the ID range ( Alvares et al, 2020 ; Bölte & Poustka, 2002 ; Duncan & Bishop, 2015 ; Furnier et al, 2023 ; Kanne et al, 2011 ; Klin et al, 2007 ; Saulnier & Klin, 2007 ). These findings suggest epidemiologic studies of co-occurring ID in children with autism based on IQ alone likely overestimate the prevalence of co-occurring ID.…”

“…Considering adaptive functioning may be especially important for identifying ID in children with autism because of the well-documented gaps between cognitive and adaptive functioning in this population, which have been reported in children as young as preschool and increase with age in cross-sectional studies ( Alvares et al, 2020 ; Duncan & Bishop, 2015 ; Kanne et al, 2011 ; Matthews et al, 2015 ; McQuaid et al, 2021 ; Pathak et al, 2019 ; Perry et al, 2009 ; Tillmann et al, 2019 ). Some children with cognitive scores below the cutoff for ID may have no significant adaptive delays or impairments and thus not meet diagnostic criteria for ID ( Furnier et al, 2023 ; Pathak et al, 2019 ). Additionally, studies looking at cognitive testing in young children have found that testability can be problematic in children with autism, resulting in underestimation of their cognitive ability by some commonly used cognitive tests, such as the Mullen Scales of Early Learning (MSEL) ( Akshoomoff, 2006 ; Courchesne et al, 2019 ; Nader et al, 2016 ).…”