Sex Differences in Dynamic Visual Scanning Patterns in School-Age Children with Autism Spectrum Disorders

Background: One of the most striking features of autism spectrum disorders (ASD) is the difference in prevalence based on sex. Due to the relatively low frequency of affected females, with a sex ratio of 4:1 (male:female) across the entire spectrum, many studies have excluded females or have included sample sizes too small to detect potential sex differences. As a result, understanding of sex-specific differences in ASD-related social behaviors and how those differences may relate to the etiology of the disorder remains limited. Recent preliminary eye-tracking research with school-age children has suggested that although boys and girls with ASD do not differ in how much they look at others’ eyes, the social adaptive value of looking at others’ eyes does differ based on sex. The present study seeks to better understand how those differences emerge and how they are manifest in visual scanning patterns on a moment-by-moment basis.

Objectives: The aims of the current study were (1) to compare time-varying visual scanning patterns in females and males with ASD and (2) to investigate how time-varying visual scanning patterns are associated with an individual’s level of social and cognitive functioning, both between sexes and within each sex.

Methods: Eye-tracking data were collected while 116 school-age children with ASD (81 boys, 35 girls) and 36 typically-developing peers (26 boys, 10 girls) viewed video scenes of children and adults engaged in naturalistic, age-appropriate social interaction within everyday settings. The ASD sample represented a broad range of level of social disability (ADOS Calibrated Severity Score: mean=10.4(4.8), range=1-10) and cognitive functioning (Full-Scale IQ: mean=95.4(21.5), range=42-149). Across diagnostic groups, both boys and girls were matched on age; within diagnostic groups, the sexes were matched based on age, IQ, and level of social disability.

Results: Results suggest that the time-varying visual scanning patterns of girls with ASD deviate from normative patterns less frequently than those of boys with ASD (p<0.001). In addition, whereas the degree of deviation from normative scanning patterns is significantly associated with level of social disability in boys (p=0.004), the relationship is not significant in girls (p>0.05). Because the timing of deviations from normative visual scanning patterns largely overlapped between boys and girls, ongoing analyses are examining how visual attention during moments of deviation may differ between sexes and mediate the relationship with level of social disability.

Conclusions: The present study finds significant sex differences in how boys and girls with ASD engage with and learn from their natural social visual environment. These results not only suggest differences in developmental etiologies, but may also support targeted, sex-specific interventions.