A Multidimensional Investigation of Sensory Processing in Autism: Parent- and Self-Report Questionnaires, Psychophysical Thresholds, and Event-Related Potentials in the Auditory and Somatosensory Modalities

Abstract

BackgroundReconciling results obtained using different types of sensory measures is a challenge for autism sensory research. The present study used questionnaire, psychophysical, and neurophysiological measures to characterize autistic sensory processing in different measurement modalities.MethodsParticipants were 46 autistic and 21 typically-developing adolescents. Participants and their caregivers completed questionnaires regarding sensory experiences and behaviours. Auditory and somatosensory ERPs were recorded as part of a multisensory ERP task. Auditory, tactile static detection, and tactile spatial resolution psychophysical thresholds were measured.ResultsSensory questionnaires strongly differentiated between autistic and typically-developing individuals, while little evidence of group differences was observed in psychophysical thresholds. Crucially, the different types of measures (neurophysiological, psychophysical, questionnaire) appeared to be largely independent of one another. However, we unexpectedly found autistic participants with larger auditory Tb ERP amplitudes had reduced hearing acuity, even though all participants had hearing acuity in the non-clinical range.LimitationsThe autistic and typically-developing groups were not well-matched, although this limitation does not affect our main analyses regarding convergence of measures within ASD. The autistic sample in the present study is not representative of the whole autistic constellation, limiting generalizability. Auditory ERPs and auditory thresholds were measured with non-equivalent stimuli.ConclusionsOverall, based on these results, measures in different sensory modalities appear to capture distinct aspects of sensory processing in autism, with relatively limited convergence between questionnaires and laboratory-based tasks. Generally, this might reflect the reality that laboratory tasks are often carried out in controlled environments without background stimuli to compete for attention, a context which may not closely resemble the busier and more complex environments in which autistic people’s atypical sensory experiences commonly occur. For this reason, sensory questionnaires may be more practically useful assessments of autistic people’s real-world sensory challenges. Further research is needed to replicate and investigate the drivers of the unexpected association we observed between auditory Tb ERP amplitudes and hearing acuity, which could represent an important confound for ERP researchers to consider in their studies.