Overall Attention to a Dynamic Social Scene in Preschoolers with Autism Spectrum Disorder and Fragile X Syndrome
Fragile X Syndrome (FXS) is the leading heritable cause of intellectual disability (ID) and the most common known monogenetic cause of autism spectrum disorder (ASD). Fifty to 75% of males with FXS meet diagnostic criteria for ASD (Harris et al, 2008). Further, 77-86% of individuals with FXS have an anxiety disorder (Cordeiro et al., 2011). Both FXS (Crawford et al. 2017) and ASD (Falck-Ytter et al., 2013) are associated with impaired social attention and decreased eye contact, and atypical looking patterns to static social information are associated with ASD and anxiety symptoms in FXS. Despite the overlapping symptoms in FXS and non-syndromic (i.e., non-FXS) ASD, it is unknown whether and how overall attention to dynamic social information compares in these two groups.
To evaluate group differences in attention to dynamic social information in children with FXS, non-syndromic ASD, and typically developing (TD) controls; and to take a preliminary, dimensional approach to evaluating how attention to dynamic social information relates to developmental ability, ASD, and social anxiety symptoms across groups.
Participants included 15 participants with FXS (nmales=10; Mage=69.35 months), 11 with non-syndromic ASD (nmales=10; Mage=44.06 months), and 18 TD participants (nmales=15; Mage=70.84 months). Groups differed in age (p<.001), so age was included as a covariate. Intellectual ability was measured by the Mullen Scales of Early Learning (MSEL) or Differential Ability Scale (DAS) [Primary outcome: NVDQ]. Severity of autism symptoms was measured using the Autism Diagnostic Observation Schedule (ADOS-2) Calibrated Severity Scale (CSS). Anxiety was measured with the Spence Children’s Anxiety Scale (SCAS-P) Social Anxiety t-score. Eye-tracking stimuli included a 3-minute video depicting an adult female seated at a table and engaging in activities designed to elicit different looking behaviors (Chawarska et al., 2012). Percent of time looking at the screen (%Valid) was computed, and group differences on this measure were evaluated. In order to take a dimensional approach to understanding how attention to dynamic social information relates to symptomology, correlations between %Valid and NVDQ, ADOS-2, and SCAS-P scores were investigated.
ANCOVA indicated a marginally significant main effect of group (F(2,36)=2.90, p=.068). Post hoc analyses indicated that the ASD group (M=85.2%) significantly differed from both the FXS (M=96.1%, p=.044) and TD (M=97.6%, p=.025) groups. %Valid was correlated for all children across groups with NVDQ (r= .394, p = .012) and ADOS-2 scores (r=-.40, p=.010) but not SCAS-P scores.
Young children with ASD show reduced task adherence or reduced interest in social scenes relative to their peers with FXS and TD. This could suggest a primary social motivation deficit in ASD that is not seen in the FXS group despite comorbid intellectual disability and the high prevalence of ASD associated with FXS. In addition, FXS is also associated with high rates of anxiety, which is often characterized by hypervigilance to threatening stimuli. It is possible that overall looking time is not sensitive to attention patterns associated with anxiety in FXS. Across all groups, more nonverbal and social impairments were associated with less attention to the social scene overall.