Relative importance of processing deficits in seven sensory modalities in predicting quantitative autistic traits in adults

Abstract Background Atypical sensory processing measured by self- or parent-report co-segregates with quantitative autistic traits (QAT) and has potential endophenotypic properties relevant to the mechanisms of autism. However, it is not known whether this association reflects a generalized sensory dysfunction or combinations of modality-specific mechanisms. Collinearity between QAT and modality-specific sensory scales limits the use of multiple regression to determine relative importance. Therefore, we combined a Bayesian variable selection method with dominance analysis to obtain a more nuanced understanding of potential modality-specific associations. Methods We recruited two independent cohorts of adults online to complete the Broad Autism Phenotype Questionnaire and the Glasgow Sensory Questionnaire (N = 592 in total). Subscale scores were derived for social, communicative, and rigid QAT and for the visual, auditory, tactile, olfactory, gustatory, proprioceptive, and vestibular sensory modalities. For each QAT, we performed a stochastic search variable selection (SSVS) procedure on the sensory modality subscales to test which sensory modalities predicted QAT while controlling for uncertainty in the other variables. Dominance analysis was then applied to the models identified by the SSVS to evaluate the relative importance of sensory modalities in predicting QAT. Results Only auditory scores reliably predicted all three QAT. The proprioceptive scale, which included motor and interoceptive deficits, specifically predicted communicative QAT. The tactile scale, which included touch sensitivity and atypical pain/temperature processing, specifically predicted social QAT. Limitations: The findings must be interpreted in light of limitations of the Glasgow Sensory Questionnaire. For example, associations between QAT and visual, olfactory, gustatory, or vestibular modalities might appear if measured in a different way. The study relied on self-report by anonymous participants, which precluded clinical evaluation of sensory difficulties. It is also important to note that the modalities found to lack associations with QAT are nevertheless known to be clinically significant in autism. Conclusions Auditory processing deficits, such as noise sensitivity, strongly predicted all QAT, whereas other sensory modalities did not. Thus, auditory processing could be further studied as a potential sensory endophenotype for autism. The results also indicate potential roles for tactile dysfunction in atypical social interaction and proprioceptive/motor dysfunction in pragmatic language.