Atypical Pupillary Light Reflex in Individuals with Autism

Abstract

Abstract : Pupillary light reflex (PLR) refers to the involuntary response whereby the pupil size changes in response to a short flash light. In this project, we will evaluate the atypical dynamic pupillary light reflex (PLR) observed in children autism. In addition, we will develop an integrated PLR-fMRI protocol for imaging PLR associated brain activities. At the end of the 3rd project year, we have tested pupillary light reflex (PLR) and heart rate variability (HRV) in 304 participants including 152 children with ASD (the ASD group), 116 children of typical development (the TD group), and 36 children with other development disorders (the NDD group). The results showed that the ASD group had significantly longer PLR latency, reduced relative constriction amplitude, and lesser constriction/redilation time than those of the TD group. Similar atypical PLR parameters were observed in the NDD group. A significant age effect on PLR latency was observed in children younger than 9 years in the TD group, but not in the ASD and NDD groups. Atypical HRV parameters were observed in the ASD and NDD groups. A significant negative correlation existed between the PLR constriction amplitude and average heart rate in children with an ASD, but not in children with typical development. We also developed an integrated fMRI/PLR protocol and have obtained fMRI data for 33 adolescents with ASD and 27 typically developing adolescents without ASD.