Scalp Topography of Event-Related Potentials Reveals Differences in Audiovisual Speech Processing in Autistic and Non-Autistic Children

Abstract

Abstract Purpose In our prior work, conventional event-related potential (ERP) responses to audiovisual versus auditory-only speech were found to explain variance in language abilities in autistic and non-autistic children but failed to differentiate autistic children from non-autistic children. This study extends previous ERP analyses of responses to audiovisual versus auditory-only speech in autistic and non-autistic school-aged children to investigate group and condition differences in the strength and topography of the ERP based on data-driven, reference-independent metrics that overcome limitations of conventional ERP analyses. Methods Extant ERP data from 50 5-12-year-old children (25 per group, matched at the group level on age and sex assigned at birth) recorded during a passive task of listening and watching videos of auditory-only and audiovisual speech syllables were analyzed for differences in ERP strength and topography, quantified via global field power (GFP) and global map dissimilarity (GMD), respectively. Results GFP was significantly reduced for audiovisual compared to auditory-only speech at 245–275 ms post-stimulus. Groups differed in GMD of the ERPs reflecting the difference in response to audiovisual versus auditory-only speech at 139–170 ms post-stimulus, wherein microstates suggested predominantly differential occipital electrode responses. Conclusions The benefits of audiovisual integration manifest as a facilitation effect (reduced signal strength of the ERP response to audiovisual versus auditory-only speech) across autistic and non-autistic children. Autistic children also display different patterns of activation underlying ERPs in response to audiovisual versus auditory-only speech relative to non-autistic children. Topographic ERP analyses show promise for advancing our understanding of audiovisual speech processing in autism.