Heart Rate Orientation Responses to the Shifts in Gaze Direction - a Follow-up Study of Low-Functioning Young Children with ASD

Background: Reduced use of eye contact is a prominent characteristic of individuals with autism spectrum disorder (ASD). In a recently published study (Helminen et al., 2017) we showed that while young, 2-5-year-old children without ASD showed stronger heart rate deceleration response, indicative of physiological orientation, to gaze shifts to direct vs averted direction, young low-functioning children with ASD did not. The result indicated that direct gaze (or gaze shifts in overall) does not attract the attention of the children with ASD, which could lead to reduced eye contact behavior.

Objectives: The objective was to follow-up the developmental course of the heart rate orientation response to direct vs. averted gaze over the 2-year period in children with and without ASD. Furthermore, the study aimed at investigating whether the heart rate orientation response could be used as a psychophysiological outcome measure for interventions aiming at increasing the children’s ability to use the eye contact in social interaction.

Methods: Twenty children with ASD (2.5 – 5.3 years, developmental age 1.2 – 4.2 years), 20 typically developing children and 18 children with developmental delay participated in the original study, and 18 ASD, 17 typically developing and 12 developmentally delayed children in the follow-up after two years. A series of facial pictures creating an illusion of dynamic gaze shifts to direct and averted gaze directions were presented, while the heart rate and eye movements were recorded. After the initial measurement, half of the children in the ASD group received a 4-months intervention based on parental guidance, aiming at increasing the children’s motivation to use the eye contact in social interaction. The experiment was repeated after intervention and after a two-year follow-up period with the same participants.

Results: In the first follow-up, the control children responded to both gaze directions with a heart rate deceleration, while the ASD children showed no heart rate deceleration to either gaze condition [ANOVA Gaze x Time after gaze shift x Group, main effect of the Group p=.009). However, according to our preliminary analysis, the children with ASD in the intervention group showed a tendency to respond to gaze shifts with a heart rate deceleration after the intervention (ANOVA Session x Time x Intervention, p=.076). In the two-year follow-up, the ASD group as a whole showed similar orientation responses to shifts in gaze direction as the non-ASD control children (ANOVA Gaze x Time x Group, main effect of time p=.003, no effects of Group).

Conclusions: The preliminary results indicated that the effect of short-term eye contact intervention might be seen in enhanced psychophysiological orientation response to the shifts in gaze direction in young children with ASD. In addition, during the course of development, also the children with ASD who receive treatment as usual, might start to show similar orientation responses to the shifts in gaze direction as non-ASD children with or without developmental delay. The potentiality of the heart rate orientation response as a psychophysiological outcome measure in the intervention studies will be discussed.