Differences in cardiac vagal modulation and cortisol response in adolescents with and without Autism Spectrum Disorder

Abstract

PurposePrevious research pointed towards a need of enhanced understanding of cardiac vagal modulation during resting and stress conditions in individuals with Autism Spectrum Disorder (ASD). This cross-sectional study addressed the following hypotheses: lower values of cardiac vagal modulation will be found in adolescents with ASD in comparison to typically developing (TD) peers; different levels of cardiac vagal reactivity and recovery will be found in adolescents with ASD; lower cardiac vagal modulation in adolescents with ASD is associated with lower psychosocial functioning and higher cortisol levels.MethodsAge and gender matched groups of adolescents (13-17 year) with ASD (n=47) and TD peers (n=47) were included. Heart rate, breathing frequency and cortisol levels were determined during baseline and a standardized stress-provoking assessment. Behavioral data concerning autism and behavioral characteristics were collected prior to the assessment.ResultsAdolescents with ASD displayed lower levels of cardiac vagal modulation during baseline and stress-provocation compared to their TD peers. However, levels of cardiac vagal reactivity and recovery were similar across groups. Weak to moderate associations were found between the level of cardiac vagal modulation and self- and parent-reported measures of autism characteristics and psychosocial functioning in adolescents with ASD. No significant associations were found between baseline cortisol levels and cardiac vagal modulation in both groups.ConclusionThese findings suggest a parasympathetic hypo-activity in adolescents with ASD and, although the level of reactivity and recovery was the same as TD peers, this hypo-activity is related to several aspects of psychosocial functioning.