Bangert, Katherine2020-09-222020-09-222020-07https://hdl.handle.net/11299/216415University of Minnesota Ph.D. dissertation. July 2020. Major: Speech-Language-Hearing Sciences. Advisor: Lizbeth Finestack. 1 computer file (PDF); vii, 95 pages.The diagnosis autism spectrum disorder (ASD), and the assessment of its severity is impeded by the subjective nature of most diagnostic tools. Objective measurements are needed to assist diagnosis and treatment monitoring for ASD. This study investigates physiological responses of children with ASD compared to children who are developing typically, while completing tasks varying in social cognitive demands. The primary measure of interest is respiratory sinus arrhythmia (RSA), a measure of parasympathetic nervous system response to the heart. Parasympathetic influence on the heart promotes a calmer state in a given environment. When parasympathetic activity increases, heart rate decreases and variability between heartbeats increases. RSA is a measure of variability in heart activity within parameters of the heart’s natural oscillatory patterns due to breathing. An increase in RSA is beneficial in some contexts that require social interaction, such as a child playing with their caregiver. A decrease in RSA is beneficial in contexts that require an increase in attentional and cognitive resources, such as an executive functioning task. In individuals with ASD, RSA has been found to differ across social and cognitive contexts. RSA in both contexts has also been found to predict performance on measures of social adaptability, language ability, and ASD symptom severity. This study compared RSA in 12 children with ASD and 8 children with typical development between the ages of 5 and 8 years across five communicative and cognitive contexts. We also investigated relationships between RSA values in each context to performance on standardized measures of cognitive, language, and social functioning. Children with ASD had significantly lower RSA in a speaking context, narrative language sample context, and executive functioning context than children with TD. For children with ASD, significant correlations were found between measures of RSA during the narrative and executive functioning contexts and expressive, receptive, and pragmatic language ability; ASD symptom severity; and parent reported measures of behavior and executive functioning abilities. The current study supports the view that RSA is a promising measure for use in assessment of ASD, and possibly a valuable tool for speech-language therapists working with this population. More research is warranted in a larger sample of children with ASD.enAutismLanguage DevelopmentRespiratory Sinus ArrythmiaThesis or Dissertation