Autonomic Activity in Individuals with Autism and Anxiety Symptoms: a Systematic Review and Meta-analysis

Autonomic activity has been identified as “atypical” in autistic relative to nonautistic individuals. In nonautistic individuals, atypical autonomic activity is associated with anxiety symptoms. Thus, this systematic review and meta-analysis aimed to assess whether atypical autonomic activity in autistic individuals is explained by the presence of anxiety symptoms. Specifically, we systematically reviewed studies investigating the association between cardiac indicators of autonomic activity (e.g., heart rate variability, respiratory sinus arrhythmia, heart rate response) and anxiety symptoms in autistic individuals. The systematic review identified 36 potential articles for inclusion (32 via databases and registers; 4 via hand searching), yielding 26 described in the qualitative review and 10 articles included in the meta-analysis or quantitative review (that were also included in the qualitative review). Results of the random effects meta-analysis revealed a significant association between respiratory sinus arrythmia collected at rest or baseline and anxiety symptoms (r = -.20).