Convergent Validity with Externalizing Behavior
Externalizing behavior was negatively correlated with RSA-R recorded
during the social condition (r = -.673, p = .008). As
RSA-R decreased, indicating withdrawal, externalizing symptomatology
increased (see Figure 1). Externalizing behavior was not significantly
related to RSA-R measured during the cognitive or emotional conditions
(r s < 0.468, p s > .05). Descriptive
statistics of RSA-R across domains and correlations with externalizing
behavior can be found in Table 3.
Discussion
This study is the first to evaluate the feasibility of the MRP and
examine domain-specific RSA-R in relation to externalizing behaviors in
young autistic children. Physiological data collection was feasible for
young children, with adequate completion and good to excellent stability
of the cognitive, emotional, and social tasks, and lower completion rate
and stability of the sensory task (Aim 1). Increased RSA withdrawal
during a social challenge correlated with higher levels of externalizing
behavior (Aim 2). Taken together, our findings highlight the feasibility
of eliciting a reliable RSA response and underscore a potential
relationship between PNS reactivity in social contexts and externalizing
behaviors.
Our results support the use of the MRP. Acquisition rates suggestthat
the social, cognitive, and emotional tasks are feasible in young
autistic children with phrase speech or fluent language. Notably, fewer
children wore sensors for the full sensory condition (Visit 1: 68%;
Visit 2: 63%) compared with the other three tasks (79-84%). Given
heightened sensory sensitivities in this population (Chistol et al.,
2018), gustatory sensory tasks may not be sufficiently feasible to
elicit a stable RSA signal. Nonetheless, additional task refinement to
increase acquisition rates may provide essential information about
sensory reactivity for a subgroup of young autistic children.
The negative relationship between externalizing behaviors and socially
elicited RSA-R highlights the value of measuring domain-specific
reactivity. Decreased RSA-R, or increased withdrawal, may reflect
physiological dysregulation and limited coping responses to challenging
situations (Graziano & Derefinko, 2013; Mezzacappa et al., 1997;
Beauchaine, 2001). However, both RSA-withdrawal and reactivity may be
adaptive depending on the context (Fenning et al. 2019). Indeed,
3.5-year-olds with elevated internalizing behaviors and moderate
baseline RSA levels had fewer longitudinal externalizing problems than
those with high or low baseline RSA (Ugarte et al. 2021). Characterizing
physiological reactivity across domains could determine optimal
domain-specific or domain-independent responses.
The specificity of the relation between externalizing behavior and RSA-R
in the social domain replicates work in neurotypical individuals and may
highlight the battery’s sensitivity to autism-specific regulatory
demands. In a meta-analysis, only tasks using negative emotional
reactivity RSA for non-autistic adults (Beauchaine et al., 2019).
Although cognitive and emotional differences may be impacted by the
heterogeneity of ASD, reduced social functioning is a core feature of
autism. Consequently, engaging in face-to-face interactions may place
the greatest self-regulatory demands on autistic children and best probe
reactivity. Indeed, difficulty adapting to social norms and reading
social cues has been linked to externalizing behaviors among autistic
individuals (Shea et al., 2018). Therefore, socially induced RSA may
reflect mechanisms linked with externalizing behaviors or better elicit
negative emotional reactivity amongst autistic children.