Sex Differences in Screening Profiles of Toddlers with Autism

Background: Research suggests that gender differences in behavior and development exist among typically developing children. For example, female toddlers tend to show more advanced language development and social reciprocity, whereas males demonstrate higher levels of physical activity (Riddoch et al., 2007; Zambrana et al., 2012). Although under-researched, gender-specific behaviors of toddlers with autism are starting to emerge in the literature. For instance, research has found differences in the manifestation of autism symptoms (e.g. females exhibiting fewer stereotypies), which may contribute to male bias in prevalence estimates (Werling & Geschwind, 2013). If sex differences in phenotypic presentations of autism exist, screening and diagnostic measures may need to be re-examined and amended.

Objectives: This study aimed to examine sex differences in screening profiles of toddlers with autism. Specifically, we examined if items on the Communication and Symbolic Behavior Scales Developmental Profile Infant-Toddler Checklist (CSBS) varied between male and female toddlers with autism.

Methods: Data were collected as part of a larger study testing a model designed to detect, evaluate, and treat autism within the first 2 years of life. Analyses for this study focused on 265 toddlers (207 males and 58 females) who failed the CSBS and were found to have autism after receiving a developmental evaluation. Multinomial logistic regression was used to model the relationship between gender and individual CSBS items, controlling for age.

Results: Gender was found to make a significant contribution to predicting only two items of the CSBS (see Table 1): males were more likely than females to score higher on items that address stringing sounds together (OR = 2.39, p < .05) and number of words used meaningfully (OR = 2.82, p < .05). Approximately one-third (31.6%) of the females, compared to one-fifth (21.3%) of the males, were reported to not string any sounds together. Almost half (46.4%) of the females, compared to one-third (30.1%) of the males, were reported to not use any words meaningfully.

Conclusions: Among toddlers with autism, the only significant gender differences were observed in two facets of expressive language: a male advantage in stringing sounds together and number of words used meaningfully. Inconsistent with patterns observed among typically developing children, this suggests that females with autism identified by the CSBS had more impaired expressive language than their male counterparts. This sheds light on the possibility that the CSBS is better at detecting females with the classic presentation of autism characterized by expressive language delay, and less sensitive in detecting ASD females without expressive language impairment.