Relationship Between Salivary ^|^alpha;-Amylase Activity and Heart Rate for Evaluation of the Sympathetic Nervous System of Children With Autism

Abstract

The purpose of the present study was to examine the validity of salivary α -Amylase Activity (sAA) as an evaluation index of the activity of the sympa- thetic nervous system (SNS) in children with autism. Participants in the study were 7 boys with autism (mean age, 107±8 months). The participants’ sAA, heart rate (HR), and exercise intensity were measured during learning that accompanied physical activity. The data were divided into 2 groups: a high- exercise intensity group and a low-exercise intensity group. The results indi- cated that both sAA and heart rate rose signi⁄cantly in the post-learning period compared to the pre-learning period; a signi⁄cant correlation was observed between the changes in heart rate value and exercise intensity just before measuring the post values. Conversely, a signi⁄cant correlation was observed between the changes in sAA value and the total amount of exercise during learning, but only in the high exercise intensity group. Recently, sAA has been studied as an index of mental stress. However, the present study, under conditions of su›cient sympathetic nervous system activation, con⁄rmed that sAA is a valid index for the evaluation of the sympathetic nervous system activity of children with autism, and revealed that although sAA and heart rate are both indices of sympathetic nervous system activity, they have di‹erent properties. Key