18890
Attentional Protective Factors in Typically-Developing 6-Month-Old Girls at High-Risk for Autism
Background: Recent studies have highlighted potential neuroprotective factors against the development of ASD that are associated with being of female gender (Robinson et al., 2013). Prospective longitudinal studies of the infant siblings of children with ASD offer the possibility of examining how these gender-specific neuroprotective factors manifest developmentally in those siblings who go on to show typical development. Given recent evidence that infant siblings who go on to develop ASD show atypical patterns of visual scanning of social scenes in the first year of life (Chawarksa et al., 2013; Klin et al., 2013; Shic et al., 2014), it is possible that gender differences in visual exploration may manifest early in development in the attentional patterns in unaffected siblings.
Objectives: To use eye tracking to examine gender differences in looking patterns towards social scenes in the first two years of life in high-risk (HR) infant siblings who receive a later diagnosis of typical development.
Methods: Participants were high- and low-risk (LR) infant siblings of children with ASD enrolled in a prospective, longitudinal study of social attention and who were judged by a multidisciplinary diagnostic team to have typically developing (TYP) outcomes at 24 or 36 months of age: HR-TYP F (n=23), HR-TYP M (n=25), LR-TYP F (n=30), LR-TYP M (n=29). All groups were comparable and in the typical range for: chronological age, verbal and nonverbal ability, and presence of autism symptoms. Participants were presented with videos of an actress emulating a bid for dyadic engagement (Spontaneous Social Monitoring Task; Chawarska et al., 2013,2014) at 6, 12, 18, and 24 months of age while their scanning patterns were recording using eye tracking. Outcome measures included longitudinal changes percentage of time looking at the scene (%Valid), the actress (%Person), and her mouth (%Mouth).
Results: Longitudinal mixed effects modeling with quadratic effects of age and fixed effect of group showed increasing %Valid and %Mouth with age in all groups (p<.05). In the LR-TYP group no gender effects were observed at any time point on any outcome measure. Relative to the LR group, the HR-TYP boys showed diminished %Valid at 12 and 18 months (p<.05) and trends for diminished %Mouth before from 6 to 18 months (p~.10). The HR-TYP girls showed increased %Valid relative to HR-TYP boys and LR-TYP girls (p<.05), and greater %Person and %Mouth compared to all other groups (p<.05).
Conclusions: High-risk infant sibling girls who develop typically show heightened attentional responses to social and communicative information early in development relative to both high-risk typically developing boys and low-risk infants. These results contrast with observed viewing strategies in high-risk TD boys, who show some evidence of residual scanning strategies more similar to HR-boys who develop ASD. Given positive predictive relationships between mouth looking and later language acquisition, and the importance of attending to people in social motivation frameworks of ASD, our results are consistent with increased risk in HR boys and attentional protective factors in HR girls.