Atypical Physiological Responses to Emotion-Eliciting Challenges in Preschoolers with ASD

Background: Emotional difficulties constitute a frequently co-occurring feature of Autism Spectrum Disorder (ASD) in young children and adults (Garon et al.,2016) and have been linked to the emergence of psychological problems such as depression, aggressive behavior problems and anxiety (Garber et al.,1995, Cole et al.,2003, Rubin et al.,1995, Morris et al.,2010). Physiological data quantified by the measure of changes in skin conductance levels (Vernetti et al.,2018), and behavioral data measured with the intensity of facial and vocal expressions (Macari et al.,2018) have shown under-reactivity to threatening, and over-reactivity to frustrating, real-world probes in 24-month-olds with ASD. However, it is not clear if this physiological phenomenon is only characteristic of toddlerhood or whether it is stable into preschool age.

Objectives: (1) To test whether preschoolers with ASD differ from typically developing (TD) controls in the magnitude of changes in SCL (ΔSCL) to real-world probes eliciting fear, anger, and joy (2) To test if ΔSCL is associated with autism severity at preschool age. Based on findings at 24months, we hypothesized that preschoolers with ASD will show greater ΔSCL in response to Anger and lower ΔSCL in response to Fear probes but not Joy probes in the ASD group.

Methods: Participants included 29 preschoolers with ASD and 41 age-matched TD controls (age: M=39.3mo, SD=3.1). ΔSCL was measured in response to multi-trial conditions eliciting Fear, Anger or Joy based on the Laboratory-Temperament Assessment Battery (Goldsmith & Rothbart,1999), using the Affectiva Q-Sensor placed on the participants’ ankle. ΔSCL was calculated between the start and end of each trial and averaged within each condition. Autism severity was assessed using the Autism Diagnostic Observation Schedule, 2^ndedition (ADOS-2, Lord et al.,2012).

Results: A LMM analysis of ΔSCL indicated a significant diagnosis x condition interaction (F(2,199)=7.99,p<.001). ΔSCL in the ASD group was higher compared to the TD group in the Anger (p=.006) and Joy (p=.008) conditions and lower in the Fear condition (p=.030). ΔSCL at 36mo was not correlated with autism severity in the overall sample (N=50), or in the ASD sample only (N=26) in any of the conditions (all rs<.24, all ps>.095).

Conclusions: As predicted, group differences in Fear- and Anger-related physiological arousal changes at 36months mirrored those previously reported at 24months, with ASD preschoolers showing an attenuated physiological response during fear-eliciting challenges and an accentuated response to anger-eliciting challenges compared to TD preschoolers. The ASD group also showed higher physiological responses than the TD group in the Joy condition. These atypical physiological responses observed in the ASD group were not associated with severity of autism symptoms. These findings suggest consistent atypical patterns of physiological responses to environmental challenges in children with ASD between 2 (Vernetti et al.,2018) and 3 years of age and underscores the need to examine links between physiological responses to emotion-eliciting challenges and later emotional difficulties in ASD. Data collection of physiological responses to emotion-eliciting challenges in preschoolers with ASD is still ongoing and will allow for the direct assessment of homo- and heterotypic continuity of physiological reactivity between 24 and 36months of age.