Studying Heart Rate Differences during Social Stimuli in Infants at Risk for ASD and ADHD

Saturday, May 13, 2017: 12:00 PM-1:40 PM
Golden Gate Ballroom (Marriott Marquis Hotel)
T. Bazelmans1, S. Greve2, T. Charman3, E. Jones4 and M. H. Johnson5, (1)King's College London, London, United Kingdom, (2)Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom, (3)Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, United Kingdom, (4)Birkbeck, University of London, London, UNITED KINGDOM, (5)Centre for Brain and Cognitive Development, Birkbeck University of London, London, United Kingdom
Background: Behavioural difficulties in Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) have been linked to atypical functioning of the autonomic nervous system (ANS). Hyper-arousal in ASD during social situations has been proposed to underlie the differences found in attention to faces. Conversely, inattention and hyperactivity in ADHD have been related to hypo-arousal in response to stimuli. The influence of the ANS during the emergence of behavioural differences in early childhood is unclear.

Objectives: The aim of this study is to see if 5-month-old infants at risk for ASD and ADHD show differences in their heart rate to social and non-social videos compared to low-risk infants. Additionally, we were interested if there are group differences in heart rate changes during the separate videos.

Methods: This preliminary data is part of BASIS (British Autism Study of Infant Siblings – www.basisnetwork.org), a longitudinal study following 5- month old infants at high familial risk for ASD (N = 34) and ADHD (N = 10) due to having an older sibling with ASD or sibling or parent with ADHD. They are compared to low-risk infants that have an older sibling but no first-degree relatives with ASD or ADHD (N = 18). Heart rate was measured continuously during an eye-tracking paradigm, starting and ending with a non-social video (NS1 and NS2). In between, two social videos were presented (Happy and Sad), counterbalanced in order. Average heart rate and changes throughout the duration of the videos were compared between groups using repeated measures ANOVAs.

Results: There is a significant effect of video type (F(2.44, 109.57) = 5.15, p = .004, ηp2 = .10). Average heart rate is lower during NS1 compared to Happy, Sad and NS2. The other three videos did not differ from each other. There are no group differences or interaction effects. For the NS1, Happy and Sad videos there is a significant effect of time (NS1: F(3.89, 229.28) = 5.88, p < .001, ηp2 = .09; Happy: F(3.09, 151.24) = 3.33, p = .020, ηp2 = .06; Sad: F(3.76, 195.67) = 4.09, p = .004, ηp2 = .07). Within-subject contrasts show that heart rate decelerates in the first 5 seconds and accelerates between 15-25 seconds. There is no significant effect of group or interaction effects.

Conclusions: This preliminary data shows that infants at low and high risk for ASD and ADHD are comparable in average heart rate and heart rate changes in response to social and non-social videos. All groups show an initial deceleration in heart rate during three of the videos, consistent with literature on deceleration in response to orienting and attention. The acceleration in heart rate can be interpreted as the termination of attention or an increase in stress. Later time points need to be considered to see if and when physiological differences emerge in development and whether they relate to later-emerging behavioural atypicalities.