Sex differences in social communication behaviors in toddlers with suspected autism spectrum disorder as assessed by the ADOS-2 toddler module

Abstract

The Autism Diagnostic Observation Schedule, 2nd-edition (ADOS-2) Toddler Module is the current gold-standard measure of autism spectrum disorder (ASD), a neurodevelopmental condition more frequently diagnosed in toddler boys than girls. Some evidence suggests that behaviors assessed by the Toddler Module may capture an ASD phenotype that is more common among boys than girls. Focus on these behaviors may contribute to sex differences in ASD diagnoses. Particularly, the ADOS-2 may equivalently weight social communication behaviors on which boys and girls are expected to look similar and behaviors that which girls may, due to early socialization, perform differently than boys. As a consequence, the Toddler Module may fail to identify ASD in girls who should qualify for the diagnosis. The current study examined the possibility that some ADOS-2 items may function differently for boys and girls by testing the degree to which eight items equivalently related to a social communication latent factor across sexes in toddlers with suspected ASD. Inconsistent with hypotheses, tests of differential item functioning revealed no evidence of sex differences, suggesting that the Toddler Module assesses these eight items similarly for boys and girls. Examination of factor loadings point to Creativity/Imagination as an area of interest for future research.

Lay abstract

When toddlers are suspected of autism spectrum disorder (ASD), the gold-standard assessment technique is with the Autism Diagnostic Observation Schedule, 2nd edition (ADOS-2) Toddler Module, a behavioral observation system. ASD is a neurodevelopmental condition more frequently diagnosed in toddler boys than in toddler girls. There is some evidence that the ADOS-2 assesses behaviors that are more characteristic of boys with ASD than girls. Thus, it is possible that focusing on these behaviors contributes at least in part to why more boys are diagnosed than girls. Specifically, girls may show more social skills than boys during the ADOS-2 assessment due to their socialization histories, which may lead to missed diagnoses of ASD in toddler girls. The current study examined eight social behaviors assessed by the ADOS-2 in a sample of toddlers with suspected ASD to see if they contributed differently to the total score of those items. Examination of those items suggested that those social communication behaviors work the same for boys and girls with suspected ASD, which was inconsistent with hypotheses. However, examination of particular items raises the possibility of examining creative/imaginative play as an area for future research.