Atypical modulation of electrodermal reactivity during exposure to graded unisensory and multisensory stimuli in autistic children and adolescents

Background Despite the substantial increase in research on sensory processing in autism, the standardization of their assessment remains non-consensual. Physiological measures such as electrodermal reactivity (EDR) are still rarely used in clinical practice, although previous studies have reported differences in reactivity between autistic individuals and the general population. This experimental study aimed to test electrodermal reactivity (EDR) as an objective and measurable marker of sensory perception in children and adolescents with autism. Methods Data were collected from 37 participants, including 21 typically developing children (11 girls and 10 boys, M = 9.86 years) and 16 autistic children (all boys, M = 11.37 years). EDR was assessed both in its tonic (SCL) and phasic (SCR) components. Participants were exposed to three types of stimuli: unisensory (visual or auditory) and multisensory (audiovisual). Each stimulus was presented at increasing intensity from the first to the third exposure (nine conditions in total). Results SCL was consistently lower in autistic participants as compared to typically developing peers. SCR was lower in autistic participants for 4 exposure conditions out of 9. In contrast, no between group differences were found in relation to stimulus intensity or between unisensory and multisensory modalities. Within-group comparisons revealed significant increases in SCR during stimulus conditions only in the control group. Additionally, no significant age-related effects were observed. Conclusions These findings highlight a specific EDR pattern in autistic children and adolescents during sensory stimulus processing characterized by hypoactivity in both tonic and phasic components of the signal. Future research should aim to better characterize this profile using a broader range of stimuli, across varied exposure contexts, and by integrating these physiological measures with cognitive assessments.