Individual neurophysiological SENSoRY profiles in AUtism – SensAUry

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication, restrictive and repetitive behaviours, but also atypical sensory responses. While a majority of studies have focused on atypical responses to social stimuli (like human voices, faces or social touch), simple and complex non-social stimulations are also atypically perceived or processed in ASD. Aberrancies in sensory processing circuits during early development could be the stepping-stone to a cascade of cognitive and social deficits. As a function of the individual developmental trajectory – and compensatory mechanisms – this atypical sensory processing could lead to various clinical profiles.
Sensory aberrancies are usually measured via questionnaires or through adapted psychomotor assessment, based on the observation of behavioural reactions (vs absence of reaction) to specific sensory stimulations or contexts. However, absence of a visible reaction is not always the signature of absence of sensitivity. Objective sensitivity can be evaluated via neurophysiological signals, such as event-related potentials (ERPs), that exhibit changes in latency and amplitude in individuals with ASD in response to social stimuli but also non-social, complex and simple, stimuli. Other studies have reported that peripheral signals, like pupil diameter, heart rate or skin conductance (i.e. indices of the autonomic nervous system), are sensitive to sensory stimulations, as well as their social content. However, these central and peripheral measures have never been used conjointly, nor explored in different sensory modalities within the same individuals. Such an approach could provide a rich neurophysiological sensory profile that could eventually be used as a biomarker of deficits (or strengths), and complement classical clinical tools.
Most neurophysiological studies exploring the sensory responses in ASD have reported group data. However, ASD is a heterogeneous disorder, and sensory profiles are likewise very diverse. Recent electrophysiological studies have thus focused on individual analyses, revealing both inter-individual and intra-individual variability. The latter corresponds to inter-trial inconsistency of the electrophysiological response to a sensory stimulation: the same stimulation does not always produce the same response in the brain, beyond the classical level of physiological noise. Greater noise during sensory encoding could affect the reliability of sensory representations, the generalization to different stimuli of a category and the discriminability from other stimuli within the same modality. Ultimately, such intra-individual variability in sensory encoding can negatively and significantly impact learning abilities and the development of numerous cognitive processes in ASD. For example, an ASD children subgroup showing an increased neural variability also exhibited a distinctive clinical profile, characterized by delayed language development.
The main aim of SensAUry is to objectively characterize individual multisensory profiles in ASD, by building and testing a short neurophysiological protocol, combining central and peripheral (autonomic) measures, several sensory modalities, and stimuli of various complexity. These individual profiles will be tested against classical sensory assessments, sensory learning abilities, ASD-adapted language assessment, psycho-clinical assessments, and typically-developing (TD) population profiles.
This objective sensory profile will contribute to the evaluation of the functional bioclinical profile of individuals with ASD, increasing our understanding of heterogeneity in autism, but also, at the individual level, helping to adapt care, environment and support by making it possible to consider individual strengths and weaknesses.