title: Functional autonomic nervous system profile in children with autism spectrum disorder.
abstract: BACKGROUND
  Autonomic dysregulation has been recently reported as a feature of autism spectrum disorder (ASD). However, the nature of autonomic atypicalities in ASD remain largely unknown. The goal of this study was to characterize the cardiac autonomic profile of children with ASD across four domains affected in ASD (anxiety, attention, response inhibition, and social cognition), and suggested to be affected by autonomic dysregulation.
  
  
  METHODS
  We compared measures of autonomic cardiac regulation in typically developing children (n = 34) and those with ASD (n = 40) as the children performed tasks eliciting anxiety, attention, response inhibition, and social cognition. Heart rate was used to quantify overall autonomic arousal, and respiratory sinus arrhythmia (RSA) was used as an index of vagal influences. Associations between atypical autonomic findings and intellectual functioning (Weschler scale), ASD symptomatology (Social Communication Questionnaire score), and co-morbid anxiety (Revised Children's Anxiety and Depression Scale) were also investigated.
  
  
  RESULTS
  The ASD group had marginally elevated basal heart rate, and showed decreased heart rate reactivity to social anxiety and increased RSA reactivity to the social cognition task. In this group, heart rate reactivity to the social anxiety task was positively correlated with IQ and task performance, and negatively correlated with generalized anxiety. RSA reactivity in the social cognition task was positively correlated with IQ.
  
  
  CONCLUSIONS
  Our data suggest overall autonomic hyperarousal in ASD and selective atypical reactivity to social tasks.
authors.affiliation: Bloorview Research Institute, 150 Kilgour Road, M4G 1R8 Toronto, Canada ; The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, M5S 3G9 Toronto, Canada.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Kushki
authors.affiliation: Bloorview Research Institute, 150 Kilgour Road, M4G 1R8 Toronto, Canada.
authors.forename: Jessica
authors.initials: J
authors.lastname: Brian
authors.affiliation: The Hospital for Sick Children, 555 University Avenue, M5G 1X8 Toronto, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Dupuis
authors.affiliation: Bloorview Research Institute, 150 Kilgour Road, M4G 1R8 Toronto, Canada.
authors.forename: Evdokia
authors.initials: E
authors.lastname: Anagnostou
keywords: Autism spectrum disorder; Autonomic nervous system; Heart rate; Respiratory sinus arrhythmia