Heart rate variability responses to different affective inputs (affective touch and affective pictures) in autistic children and typically developing peers

Heart rate variability (HRV) expresses autonomic responses to emotion perception. Although HRV has been examined during affective stimuli in autistic children, no evidence exists about differences in HRV produced by different stimulus modalities. This cross-sectional study aimed at comparing HRV during two modalities (affective touch and affective pictures) in autistic children and typically developing peers (TDP), and at exploring the factors influencing emotion-related HRV. HRV time, frequency and non-linear indexes from 20 autistic children and 20 TDP were measured during resting state and different affective stimuli: affective/non-affective touch and pleasant/unpleasant/neutral pictures. Children rated stimulus valence and arousal and performed a task of emotion knowledge, and parents completed questionnaires on emotion regulation, behavior and sensory reactivity. Affective touch produced greater HRV responses in autistic children, whereas affective pictures modulated HRV in their TDP. Age, but not cognition, correlated with HRV in autistic children; scores of emotion knowledge, emotion regulation and behavior problems were associated with HRV indexes during affective stimulation in autistic children and TDP. Different modalities of affective stimulation produce specific ANS regulation in autistic children. This must be considered for the design of experimental procedures and in the development and application of intervention protocols. • Heart rate variability (HRV) is a marker of the physiological response to emotion. • Differences in HRV produced by different affective stimuli are unknown in autism. • Affective touch induced higher HRV responses than visual stimuli. • HRV is influenced by age and affective and behavioral problems. • Protocols for autistic children must consider the nature of affective stimuli.