Electrodermal Activity as a Metric of Arousal in Autistic Children Prior to Dental Treatment

Abstract

Highlights This study aimed to examine autistic children’s arousal characteristics during the initial rest period before routine dental treatment and their relation to behavior. What are the main findings? Increased autism traits predicted tonic EDA level (skin conductance level; SCL) trajectories over time: children with fewer autism traits showed increasing SCL across the rest period, whereas children with higher autism traits displayed physiological habituation (declining SCL). Additionally, generalized anxiety significantly predicted lower phasic EDA activity (non-specific skin conductance response frequency; NS-SCR). After controlling for cognitive functioning (IQ), a significant quadratic (inverted U-shaped) relationship between anxiety and NS-SCR frequency emerged. No significant relationships were observed between EDA measures and sensory over-responsiveness or expressive language. What are the implications of the main findings? Baseline physiological arousal in autistic children appears to reflect distinct within-population profiles and trajectory patterns linked to autism traits and anxiety, rather than a uniform hyper- or hypo-arousal state. In addition, individual differences in cognitive functioning (IQ) may obscure non-linear relationships between physiological arousal and anxiety and should be considered in future EDA studies. Methodological and contextual factors (e.g., measurement approach, environmental conditions, participant heterogeneity) likely influence EDA outcomes, underscoring the need for standardized protocols and multi-measure approaches in future research. Abstract Several prominent theories have asserted atypical arousal as a biological feature of autism. However, there is mixed evidence regarding atypical arousal patterns, particularly resting-state arousal, in autistic children, with research increasingly using psychophysiological measures, such as electrodermal activity (EDA), to help elucidate arousal levels in individuals who might not otherwise be able to identify such states. This study analyzed extant EDA data from 135 autistic children (6–12 years) collected during a baseline rest period in a dental environment to determine the relationships between tonic (mean skin conductance level; SCL) and phasic (frequency of non-specific skin conductance responses; NS-SCRs) arousal and participant characteristics, including sensory over-responsiveness, autism traits, expressive language, and general anxiety. EDA data were collected using pre-gelled electrodes placed on the distal phalanges of the participant’s non-dominant hand using the BIOPAC MP150 system. Data preprocessing and epoch analyses were conducted using BIOPAC AcqKnowledge software. Conditional linear and, for the outcome variable anxiety, quadratic growth models were used to assess the temporal (within-participant across observations) relationship between EDA and behavioral variables. The results revealed a significant time-by-autism trait interaction for SCL, as well as linear and quadratic relationships between anxiety and NS-SCRs. No significant relationships were found between EDA arousal parameters and sensory over-responsiveness or expressive language abilities. A significant covariance relationship between SCL and NS-SCR frequency was also observed. Collectively, these results support previous characterizations of unique, within-autism-population arousal profiles related to autism traits, anxiety, and tonic-to-phasic covariance patterns.