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Title page for ETD etd-12072015-115206


Type of Document Dissertation
Author Edmiston, Elliot Kale
Author's Email Address kale.edmiston@vanderbilt.edu
URN etd-12072015-115206
Title Biobehavioral Response to Social Judgment in Adolescents with Autism Spectrum Disorder
Degree PhD
Department Neuroscience
Advisory Committee
Advisor Name Title
Paul Newhouse Committee Chair
Beth Malow Committee Member
Mark Wallace Committee Member
Tedra Walden Committee Member
Keywords
  • HPA axis
  • respiratory sinus arrhythmia
  • autism spectrum disorder
  • salivary cortisol
  • adolescence
  • stress
  • trier social stress test
Date of Defense 2015-11-23
Availability unrestricted
Abstract

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social behavior. It is unclear if deficits are due to disinterest in social stimuli, or to an elevated stress response. The autonomic nervous system and hypothalamic pituitary adrenal axis facilitate arousal, as well as approach and avoidance behavior in response to sensory information, including social stimuli. Research in our lab has shown blunted responsivity to social judgment in children with ASD. Previous work has also demonstrated alterations in autonomic regulation, including respiratory sinus arrhythmia (RSA), a measure of PNS function. The majority of prior work has focused on children with ASD, but adolescents with ASD have been understudied. The adolescent period is of interest, as this developmental epoch is associated with increased salience of social judgment in typically developing (TD) populations.

In this study, we employed the Trier Social Stress Test (TSST) to study RSA and salivary cortisol response to social judgment in ASD compared to TD adolescents.

Participants underwent a modified version of the TSST, in which one of the raters was replaced with an age-matched peer. At arrival and during the TSST, ECG was obtained. Salivary cortisol data was obtained prior to and following the TSST. Operationalized behavior coding was collected using video recordings of the TSST. RSA was calculated from ECG. We performed repeated measures ANOVA to determine group differences in RSA, as well as for behaviors. Paired sample t-tests were used to calculate within-group cortisol response to the TSST.

TD participants showed higher mean RSA values than ASD participants at all time points. Cortisol data showed a significant increase in response to the TSST in the TD group but not the ASD group. The TD group showed more displacement behaviors than the ASD group.

Our findings indicated reduced regulatory capacity as indexed by RSA in ASD adolescents compared to TD peers. The lack of a cortisol response to the TSST in the ASD group could suggest that the TSST is not interpreted as stressful or salient for ASD participants, as does the reduced displacement behaviors in the ASD group.

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