Auditory and visual discomfort in autism.

Autism is a neurodevelopmental condition affecting 1 in 100 individuals and sensory processing differences are recognised diagnostic criteria (American Psychiatric Association, 2013). One sensory processing difference found in autism is hyperreactivity to sensory stimuli, making public spaces like supermarkets uncomfortable and painful, due to a bombardment of sensory information across all senses (MacLennan et al., 2021). Whilst it is rare to experience just an overload of one sense, lab-based research into hyperreactivity tends to focus on sensory modalities separately (Parmar et al., 2021; Gomes et al., 2008). My PhD aims to identify the precise sensory parameters that lead to discomfort for autistic people across multiple modalities, as to build an evidence-base to inform adaption of facilities/ resources to become inclusive. Specifically, by considering auditory and visual information together, I will determine whether these have an additive effect on discomfort, or whether the effect is larger than the sum of its parts (superadditive.) My PhD will include 4 studies: The sample (based on a simulation power analysis) will comprise 30 children with a clinical autism diagnosis aged 6-14 years and 30 age-, gender- and non-verbal ability-matched typically developing (TD) controls. I will exclude children with epilepsy/ migraine. I will exclude children with IQ 70, and those with visual/ hearing problems. The Lifetime Social Communication Questionnaire will be an inclusion criterion in autism (15) and TD (15) groups (Rutter et al., 2003). Building on pilot data I collected with a research placement bursary, Study 1 will identify the precise visual parameters that cause discomfort in autistic children. Autistic and TD children will rate static visual stimuli from comfortable to uncomfortable. I will build Generalised Linear Mixed Models (GLMM) to predict comfortable/ uncomfortable ratings with fixed effects for stimulus parameters and group. I hypothesise that autistic children will find similar features uncomfortable as TD children, meaning that the interaction terms between stimulus parameters and group will be non-significant. However, if we find significant interactions, this will show that autistic and TD children find different stimulus features uncomfortable. Study 2 will identify potential auditory parameters linked to discomfort through a systematic review, to inform study 3. I will search databases (like PubMed) for papers with search terms including auditory, sound, discomfort and hyperreactivity and follow PRISMA reporting guidelines. Study 3 will follow a similar method as study 1, but for auditory stimuli, to identify the precise auditory parameters that cause discomfort in autistic children. Study 4 will determine discomfort for auditory stimuli alone and visual stimuli alone, and auditory and visual stimuli together, through discomfort ratings. I hypothesise there will be a superadditive effect, and combining visual and auditory stimuli will lead to greater discomfort than the sum of its parts. My research will provide insight into how autistic individuals experience multisensory information, with direct practical benefits. Superadditive effects would demonstrate how changing just one aspect of sensory overwhelming spaces could produce a decreased overall sensory burden, even if hyperreactivity is occurring in multiple senses; enabling easier, cost-efficient changes to create more accessible environments.