Parasympathetic functions in children with sensory processing disorder

Roseann C. Schaaf

doi:10.3389/fnint.2010.00004

Abstract

The overall goal of this study was to determine if parasympathetic nervous system (PsNS) activity is a significant biomarker of sensory processing difficulties in children. Several studies have demonstrated that PsNS activity is an important regulator of reactivity in children, and thus, it is of interest to study whether PsNS activity is related to sensory reactivity in children who have a type of condition associated with sensory processing disorders termed sensory modulation dysfunction (SMD). If so, this will have important implications for understanding the mechanisms underlying sensory processing problems of children and for developing intervention strategies to address them. The primary aims of this project were: (1) to evaluate PsNS activity in children with SMD compared to typically developing (TYP) children, and (2) to determine if PsNS activity is a significant predictor of sensory behaviors and adaptive functions among children with SMD. We examine PsNS activity during the Sensory Challenge Protocol; which includes baseline, the administration of eight sequential stimuli in five sensory domains, recovery, and also evaluate response to a prolonged auditory stimulus. As a secondary aim we examined whether subgroups of children with specific physiological and behavioral sensory reactivity profiles can be identified. Results indicate that as a total group the children with severe SMD demonstrated a trend for low baseline PsNS activity, compared to TYP children, suggesting this may be a biomarker for SMD. In addition, children with SMD as a total group demonstrated significantly poorer adaptive behavior in the communication and daily living subdomains and in the overall Adaptive Behavior Composite of the Vineland than TYP children. Using latent class analysis, the subjects were grouped by severity and the severe SMD group had significantly lower PsNS activity at baseline, tones and prolonged auditory. These results provide preliminary evidence that children who demonstrate severe SMD may have physiological activity that is different from children without SMD, and that these physiological and behavioral manifestations of SMD may affect a child's ability to engage in everyday social, communication, and daily living skills.

Highlights

5–10% of the non-disabled population and 30% of children with disabilities experience atypical responses to sensory stimuli that interfere with their ability to fully participate in home, school, and community activities (Baranek, 1998; Ahn et al, 2004)
There were no significant differences between groups on mean Vagal tone (VT) during recovery or prolonged auditory stimuli
The sensory modulation dysfunction (SMD) group returned to baseline level of VT at recovery whereas the typically developing (TYP) group shows lower VT at recovery compared to baseline

Summary

Introduction

5–10% of the non-disabled population and 30% of children with disabilities experience atypical responses to sensory stimuli that interfere with their ability to fully participate in home, school, and community activities (Baranek, 1998; Ahn et al, 2004). We use the term sensory modulation dysfunction (SMD) to refer to patterns of atypical responses to typical levels of sensation Lane (Lane, 2002). SPD is thought to occur when sensory information is perceived and interpreted in a disorganized way so that the persons ability to use sensory information to act and interact with their environment is impaired (Miller, 2006). This disorder was originally described and researched by Ayres (1972, 1979).

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