Category: Child / Adolescent - Anxiety

Symposium

Eyes on Anxiety: Pupillometry Evidence for Hyperarousal in Autism Spectrum Disorder

Friday, November 17
12:00 PM - 1:30 PM
Location: Sapphire Ballroom B, Level 4, Sapphire Level

Keywords: Autism Spectrum Disorders | Anxiety
Presentation Type: Symposium

Background. Atypical sensory function has been linked to elevated levels of anxiety in autism spectrum disorders. Recent fMRI data (Top et al., 2016) suggest that adults with autism have difficulty differentiating between threat and safety cues, meaning that the world may be often experienced as scary even during non-threatening situations. Here we investigated response to sensory stimuli (auditory tones) to evaluate two related hypotheses: a) people with autism generally experience greater levels of physiological arousal; b) people with autism have delayed habituation to potentially threatening stimuli.


Methods. Participants were 91 adults (mean age = 22.27, SD = 4.05, range = 18-35) including adults with diagnosed autism spectrum disorder (ASD group, n=31, 20 males), adults seeking treatment for high anxiety but not autism (ANX group, n=28, 11 males), and non-anxious neurotypical controls (NT group, n=35, 23 males). Participants wearing high-fidelity headphones looked at a fixation cross in front of them while eye-tracking technology measured pupil dilation as an index of physiological arousal. The auditory habituation protocol consisted of three blocks with 10 trials per block for a total of 30 trials. For each trial, after a 500ms delay, a sound stimulus was presented with a jittered mean of 2000ms (range 1800-2200ms) followed by a jittered 20000ms inter-trial-interval (range 18000-22000ms). The first block consisted of “silent” tones (with no audible sound) as a baseline condition. The second block of trials utilized a 60db, 2000Hz sinewave tone and the third block utilized a slightly louder, more unpleasant 80db 2000Hz sawtooth tone.


Results. Hierarchal Linear Modeling analyses showed that the ASD group showed greater tonic pupil size than both comparison groups during the baseline silence condition. All groups demonstrated habituation to the repeated tones and there were no between-group differences. The ASD and ANX groups had higher levels of dimensional autism symptoms and intolerance of uncertainty scores than the NT group but did not differ from each other; the ANX group had significantly higher anxiety scores than the others. However, there were no significant correlations between pupillometry measures and anxiety questionnaires.


Conclusions. People with autism may have markedly elevated psychophysiological arousal even above that of other anxious adults, including increased threat attribution for sensory experiences. This may not be apparent through standard anxiety questionnaires, which may not adequately capture the experience of anxiety in autism (Kerns et al., 2014). Exploring and identifying indicators of bodily tension, addressed with biofeedback and/or mindfulness techniques, may be particularly helpful for adults with ASD.

Nicholas Top

Graduate Student
Brigham Young University

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