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

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.