Social Pupillary Response in Children and Adolescents with Autism Spectrum Disorder

Background: The neural mechanisms underlying autism spectrum disorder (ASD) have been found to vary significantly across the life span. For example, prior research has shown enlarged brain volume and neuronal overgrowth in individuals with autism up until they hit adolescence when abnormal degeneration occurs (1,3). Eye tracking and pupillometry have been used extensively in studies of social processing and autonomic response in ASD (2,6) and allow further investigation into the age-specific neurophysiologic differences associated with the progression of autism.

Objectives: The primary aim of this study was to utilize pupillary response to visual stimuli as a way to explore potential age-specific social processing abnormalities associated with ASD.

Methods: Individuals between the ages of 5 and 30 with a clinical diagnosis of ASD and age- and gender-matched typically developing controls (TDC) were recruited at Indiana University. Participants viewed a 60-second, side-by-side social scenes and geometric patterns eye tracking paradigm similar to those used in previous studies of social processing in ASD (4,5). The primary measures were average and maximum Social to Geometric Pupil Ratio (SGPR_avg, SGPR_max). All ASD participants underwent a battery of psychological testing and caregiver behavioral evaluations. Participants were further grouped into adolescent and child cohorts depending on whether they were older or younger than 12 years old.

Results: Thirty-seven ASD and twenty-six TDC provided evaluable pupillometry data. There was no difference between ASD and TDC individuals in pupillary measures nor was there a correlation between pupillary measures and age. Notably, there was a statistically significant interaction between ASD vs. TDC and adolescent vs. child on SGPR_avg [F(1, 63)=4.349, p=0.042] with the child ASD group having an elevated social pupillary response and the adolescent ASD group having a decreased response compared to TDC.

Conclusions: The interaction between ASD vs. TDC and adolescent vs. child on social pupillary response indicates that changes in adolescence may have an effect on social responsiveness in individuals with ASD. Further investigation into the age-specific neural mechanisms underlying social processing in ASD is required.

 

 

 

References:

1. Aylward, E.H., Minshew, N.J., Field, K., Sparks, B.F., & Singh, N. (2002). Effects of age on brain volume and head circumference in autism. Neurology, 59(2), 175-183.

2. Boraston, Z., & Blakemore, S. J. (2007). The application of eye-tracking technology in the study of autism. The Journal of physiology, 581(3), 893-898.

3. Courchesne, E., Pierce, K., Schumann, C., Redcay, E., Buckwalter, J.A., Kennedy, D.P., & Morgan, J. (2007). Mapping early brain development in autism. Neuron, 56(2), 399-413.

4. Gaietto, K., Shaffer, R., Warner, K., Mathieu-Frasier, L., Wink, L.K., & Erickson, C. (2014). Eye tracking utilizing age matched social scenes and geometric shapes. International Meeting for Autism Research (IMFAR) Atlanta, Georgia.

5. Pierce, K., Conant, D., Hazin, R., Stoner, R., & Desmond, J. (2011). Preference for geometric patterns early in life as a risk factor for autism. Archives of general psychiatry, 68(1), 101-109.

6. Sweeney, J. A., Takarae, Y., Macmillan, C., Luna, B., & Minshew, N. J. (2004). Eye movements in neurodevelopmental disorders. Current opinion in neurology, 17(1), 37-42.