Response to Distress in 12-Month-Old Infants with Familial Risk for ASD

Background: Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorder characterized by core deficits in social communication skills. Infants with familial risk for ASD (i.e., younger siblings of children with ASD) have a recurrence rate of 18.7%, with infants from multiplex families (i.e., multiple affected siblings) carrying an additional twofold increase in risk compared to those from simplex families (i.e., one affected sibling; Ozonoff et al., 2011). Although several studies have demonstrated deficits in empathic response to others' distress in toddlers with familial risk at 2-3 years of age (Campbell et al., 2017; Hutman et al., 2010; McDonald et al., 2012), only one study has examined empathic responding in infants with familial risk at 12 months, when empathic behavior first begins to emerge in typical development. Here, we examined the response to distress at 12 months in infants at variable risk for ASD (both multiplex and simplex infants) and compared them to low-risk (LR) infants.

Objectives: (1) Compare infant responses to others’ distress at 12 months between risk groups. (2) Examine whether infant responses to others’ distress correlate with standardized measures of social communication skills. (3) Examine whether infant responses to others’ distress predict 18-month ASD symptoms.

Methods: Participants included 23 LR, 26 simplex, and 9 multiplex infants at 12 and 18 months of age. During the simulated distress paradigm, an examiner pretended to hit her finger with a toy mallet. Attention to distress, defined by the proportion of time infants paid attention to the person in distress, was coded. Other measures of 12-month social behavior included: Early Social Communication Scales (initiation of joint attention [IJA], initiation of behavioral requests [IBR], response to joint attention [RJA]) and Autism Observation Scale for Infants (AOSI total score). At 18 months, ASD symptoms were measured with the Autism Diagnostic Observation Schedule–Toddler Module (ADOS-T).

Results: (1) Attention to distress did not significantly differ based on risk group (table 1), although multiplex infants had lower scores than the other two groups. (2) Attention to distress was significantly positively correlated with IBR, but not IJA, RJA or AOSI at 12 months (table 2). (3) Attention to distress was negatively correlated with the ADOS-T Social Affect score at 18 months (table 2). A linear regression model with all 12-month variables significantly predicted ADOS-T total score (R²=0.378, F(5,39)=4.731, p=0.002); RJA (b=-0.313) and AOSI (b=0.253) explained the most unique variance in 18-month ADOS-T score.

Conclusions: Findings are consistent with previous work indicating that a lack of response to distress during infancy and toddlerhood is an important early sign of atypical social development, which is specifically related to emerging ASD symptoms and not to familial risk. Results also suggest, however, that it is important to measure a range of social behaviors when assessing risk for ASD. This study highlights the need for early interventions to enhance empathic responses and social communication skills starting as early as 12 months of age. Next steps include examining other aspects of infants’ responses to distress, including empathic concern and hypothesis testing.