Multisensory Integration of Naturalistic Speech and Gestures in Autistic Adults

Abstract Seeing the speaker facilitates auditory speech comprehension through audio-visual integration. This is especially the case in challenging listening conditions, such as in real-life social environments. Autism has been associated with atypicalities in integrating audio-visual information, potentially underlying social difficulties in this population. The present study investigated multisensory integration (MSI) in speech processing among autistic (N=35) and neurotypical (N=35) adults. Participants performed a speech-in-noise task in a realistic multispeaker social scenario with audio-visual, auditory, or visual trials while their brain activity was recorded using EEG. The neurotypical group demonstrated a non-linear audio-visual interaction in alpha suppression, whereas the autistic group showed merely additive processing of these same inputs. Despite these differences in neural correlates, both groups achieved similar behavioural audio-visual facilitation outcomes. These findings suggest that although autistic and neurotypical brains might process multisensory cues differently, they achieve comparable benefits from audio-visual speech. These results contribute to the growing body of literature on MSI atypicalities in autism. Competing Interest Statement The authors have declared no competing interest. Funding Statement This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no 945380, DAAD PRIME Fellowship, Agencia Estatal de Investigacion grant PID2019-108531GB-I00 AEI/FEDER, and AGAUR Generalitat de Catalunya grant 2021 SGR 00911. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol and data handling were approved by the Institutional Committee for Ethical Review of Projects at University Pompeu Fabra (number 258). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes (magdalenaanna.matyjek{at}upf.edu; (s.kita{at}warwick.ac.uk; (mireia.torralba{at}upf.edu; (salvador.soto{at}upf.edu) Competing Interest Statement The authors declare no competing (financial or otherwise) interests. Funding statement This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no 945380, DAAD PRIME Fellowship, Agencia Estatal de Investigación grant PID2019-108531GB-I00 AEI/FEDER, and AGAUR Generalitat de Catalunya grant 2021 SGR 00911. Data Availability The data and analysis code are available at https://osf.io/2b6s3/ (subproject: MSI in autistic vs. neurotypical adults).