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Comparison of Rsa during a Relaxation Task Between ASD, Anxiety, & Controls

Saturday, May 17, 2014
Atrium Ballroom (Marriott Marquis Atlanta)
L. Guy1, M. C. Souders2, C. M. DeLussey3, C. M. Kerns4 and J. Herrington5, (1)The Children's Hospital of Philadelphia, Philadelphia, PA, (2)University of Pennsylvania School of Nursing/The Children's Hospital of Philadelphia, Philadelphia, PA, (3)Center for Autism Research, The Children's Hospital of Philadelphia, Philadelphia, PA, (4)AJ Drexel Autism Institute, Drexel University, Philadelphia, PA, (5)University of Pennsylvania, Philadelphia, PA
Background:

Respiratory sinus arrhythmia (RSA), a measure of heart rate variability, reflects the action of the parasympathetic nervous system on heart rate.  A higher RSA is associated with better physical and emotional health, and a more adaptive response to changing environmental demands.  Recent studies have used RSA to better understand the anxiety symptoms and social deficits in ASD.  Social impairment is a defining feature of ASD, and anxiety is a commonly occurring comorbid condition with rates at approximately 40%.  To our knowledge no studies have yet compared RSA for individuals with ASD with and without anxiety to individuals with an anxiety disorder alone.

Objectives:

The aim of this study was to compare RSA during a relaxing task across four groups of participants who were well-characterized using gold standard measures for ASD (i.e., the ADOS) and Anxiety (i.e., the ADIS).  It was hypothesized that individuals with ASD regardless of their anxiety status would have a lower RSA than either the Anxiety alone group or controls because of social impairments associated with the disorder.  It was also predicted that RSA would be related to better socialization skills and executive function skills involved in behavior regulation.

Methods:

Participants included a total of 68 children between the ages of 7-17 who were grouped according to the presence or absence of (1) ASD and (2) an Anxiety disorder, yielding four groups:  ASD only, ASD plus anxiety disorder, anxiety disorder without ASD, and typically developing controls (TDC).  IQ was assessed using the DAS-II; executive function skills were assessed by BRIEF parent report; behavioral function was assessed by CBCL; and socialization skills were assessed by the Vineland (VABS) parent interview. ECG data were collected using the Biopac MP150 system and a standard Lead-II configuration, at a sampling rate of 1000 Hz.  The relaxation task involved participants watching a 5-minute video of a dynamic beach scene with gentle rolling waves.

 Results:

 ANOVAs indicated no significant group differences for age, F(4,67)=.249, p=ns (ASD only M=12.59; ASD plus anxiety M=11.08; Anxiety M=11.50, TDC M=12.25) or composite IQ, F(4,67)= .902, p=ns, (ASD only M=105; ASD plus anxiety M=97; Anxiety M=104; TDC M=110).  There was a significant group main effect for RSA during the relaxation task, F(4,67)= 2.62, p=.042.  Follow-up analyses showed this was driven by the ASD only group being significantly lower than the TDC group, p=.034.  There were no significant differences between the other groups.  RSA was positively correlated with adaptive Socialization skills, r=.198, p=.054 and negatively correlated with social problems on the CBCL, r=-.220, p=.036.  There was a significant negative correlation between RSA and BRIEF Behavior Regulation skills, r=-.205, p=.046.

 Conclusions:

Study findings supported the hypothesis that individuals with ASD would have significantly lower RSA than controls, and that RSA is associated with social functioning and behavior regulation.  Counter to predictions, RSA was not associated with anxiety symptoms in the present sample.  Data analysis is ongoing.