Respiratory Sinus Arrhythmia (RSA) Reactivity and Developmental Delay in the Preschool Years

Children with developmental delay are more likely than their typically developing peers to experience emotional dysregulation. Given that there is evidence that respiratory sinus arrhythmia (RSA) reactivity indexes emotion regulation, which in turn tracks motor, language, and cognitive development across the early years, RSA reactivity should develop accordingly in that period and differ by developmental status. The present study therefore compared those with and without developmental delay (across adaptive, personal–social, and motor domains) on the growth in RSA reactivity in the preschool years (ages 3–5 years) across three time points. Results showed that those with global developmental delay exhibited atypical RSA reactivity progression (e.g., excessive or insufficient vagal withdrawal) across the preschool years. Follow-up is needed to determine whether this pattern of RSA reactivity persists later in childhood.