Sex Differences in Social Communication Behaviors in Toddlers with Suspected Autism Spectrum Disorder as Assessed by the ADOS-2 Toddler Module

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.