Association Between Gastrointestinal Disorder and Cardiovascular Responses to Stress In Autism Spectrum Disorders

Background:  Gastrointestinal (GI) problems appear to be prevalent in children suffering from Autism Spectrum Disorders (ASD) (e.g., Williams et al., 2010), and evidence suggests that ASD patients have a heightened response to stress (Corbett et al., 2008).  Moreover, an association exists between stress and GI disorders (Suarez et al., 2010).  However, despite this knowledge, the relationship between stress indices and GI disturbances has not been fully explored in ASD.

Objectives:  As a marker for stress, we examined the relationship between cardiovascular reactivity in children with ASD both with and without gastrointestinal disorders or significant GI symptomatology. We hypothesized that the cardiovascular reactivity in children and adolescents with ASD with a GI disorder or significant GI symptomatology would be higher than those with ASD alone. Heart rate and blood pressure were used as indicators of sympathetic nervous system activation in response to auditory and vibrotactile stimulation as well as cold temperature.

Methods:  GI symptomatology was assessed and quantified using the Autism Treatment Network Registry GI Symptoms Inventory. Children and adolescents with an ASD diagnosis with a comorbid GI disorder or significant GI symptomatology and those with ASD without a GI diagnosis or significant GI symptomatology had their heart rate and blood pressure taken immediately after a baseline condition as well as during conditions of auditory, vibrotactile, and cold temperature stimulation.

Results:  Preliminary results indicated that heart rate and blood pressure were significantly higher for the ASD group with GI disturbances for the cold pressor condition when compared to children with ASD alone.

Conclusions:  Preliminary results from our pilot study suggest that cardiovascular reactivity to sensory stimulation in the domain of cold temperature may differ in those with ASD with a GI disorder or significant GI symptomatology relative to those with ASD alone.  Although our data indicate differences in physiological responding among the groups, a larger sample size is needed to determine if the effects can be substantiated.  Identifying the aspects contributing to GI problems in ASD will be important for optimizing future treatment strategies.