Sensory salience processing moderates attenuated gazes on faces in autism spectrum disorder: a case-control study.

Researchers studied eye movements in 166 autistic children and adults compared to 166 non-autistic people while watching videos. They found that autistic participants looked at faces less often and had different pupil responses when viewing scenes with or without people. The study suggests that differences in how autistic people process sensory information might contribute to reduced attention to faces and social cues.

This case-control study examined eye-tracking patterns in 166 autistic participants and 166 neurotypical controls (ages 6-30 years) while viewing social scenes. Researchers investigated how sensory salience processing, measured through gaze patterns and pupil responses, affects social attention in autism. Results showed autistic participants had reduced attention to faces throughout scenes, with pupil responses differing between human and non-human scenes compared to controls. Crucially, altered sensory salience processing appeared to moderate the reduced face-gazing behavior in autism.

The study suggests that the locus coeruleus-norepinephrine system, indexed by pupillary responses, may contribute to differences in how autistic individuals process social information by affecting attention to sensory features in the environment.

Findings suggest interventions targeting sensory processing and attention regulation might help improve social attention in autism. Understanding individual differences in arousal responses could inform personalized approaches to social skills training and environmental modifications.

Small to moderate effect sizes limit clinical significance. Naturalistic design prevented experimental control of stimuli. Age and IQ effects suggest findings may not generalize across all developmental levels. Pupillary responses as proxy measures may not fully capture neurobiological mechanisms.

Attenuated social attention is a key marker of autism spectrum disorder (ASD). Recent neuroimaging findings also emphasize an altered processing of sensory salience in ASD. The locus coeruleus-norepinephrine system (LC-NE) has been established as a modulator of this sensory salience processing (SSP). We tested the hypothesis that altered LC-NE functioning contributes to different SSP and results in diverging social attention in ASD.

We analyzed the baseline eye-tracking data of the EU-AIMS Longitudinal European Autism Project (LEAP) for subgroups of autistic participants (n = 166, age = 6-30 years, IQ = 61-138, gender [female/male] = 41/125) or neurotypical development (TD; n = 166, age = 6-30 years, IQ = 63-138, gender [female/male] = 49/117) that were matched for demographic variables and data quality. Participants watched brief movie scenes (k = 85) depicting humans in social situations (human) or without humans (non-human). SSP was estimated by gazes on physical and motion salience and a corresponding pupillary response that indexes phasic activity of the LC-NE. Social attention is estimated by gazes on faces via manual areas of interest definition.

SSP is compared between groups and related to social attention by linear mixed models that consider temporal dynamics within scenes. Models are controlled for comorbid psychopathology, gaze behavior, and luminance. We found no group differences in gazes on salience, whereas pupillary responses were associated with altered gazes on physical and motion salience. In ASD compared to TD, we observed pupillary responses that were higher for non-human scenes and lower for human scenes.

In ASD, we observed lower gazes on faces across the duration of the scenes. Crucially, this different social attention was influenced by gazes on physical salience and moderated by pupillary responses. The naturalistic study design precluded experimental manipulations and stimulus control, while effect sizes were small to moderate. Covariate effects of age and IQ indicate that the findings differ between age and developmental subgroups.

Pupillary responses as a proxy of LC-NE phasic activity during visual attention are suggested to modulate sensory salience processing and contribute to attenuated social attention in ASD.