Children with SMD demonstrate atypical behavioral responses to sensation which can impair their ability to participate in a variety of activities including educational, social, and self care activities. Investigation of SMD is important because early identification of SMD and the initiation of an intervention program designed to remediate atypical responsiveness to sensation may help decrease the long-term affects of SMD and serve to enhance the individual's ability to participate in activities. This reactivity is associated with abnormal behavioral responses on a parent rating scale of functional behaviors. Thus, preliminary evidence links underlying physiologic reactivity to hyper-reactive behavioral symptoms. However, it is necessary to further validate this finding with additional physiological and behavioral measures.
Vagal tone is a measure that reflects central modulation of autonomic function.
Cardiac vagal tone, therefore, can provide a measure of ANS functioning and homeostatic feedback. This project will investigate whether differences in sensory reactivity between children with SMD and a normally developing comparison group are reflected in vagal tone. Behavioral measures of responses to sensation and how these affect participation in daily activities will also be examined using the Short Sensory Profile. Thus linkages between SMD, physiological reactivity and functional behavior will be investigated. VT will correlate with abnormality on the Short Sensory Profile.