Individuals with autism spectrum disorder (ASD) often report that their sensory processing difficulties are particularly bothersome. However, the specific sensory problems that individuals with ASD report often seem self-contradictory; in particular, individuals with ASD can respond excessively to certain sensations, but insufficiently to other sensations.
Recently, a number of psychophysical paradigms (e.g., spatial suppression, habituation and various sensory illusions) across different sensory modalities have supported the hypothesis that these apparent contradictions may stem from changes in “gain control” and dynamic inhibition among individuals with ASD. These paradigms have demonstrated that when the nervous system does not sufficiently modulate its response to a target sensory input based upon the context in which this input occurs, both excessive and insufficient responses to sensations can occur. Despite their promise, many of these paradigms require participants to follow instructions and deliver responses about their subjective sensations. This can be difficult or impossible for some individuals with ASD.
In this project, April Levin aims to use electroencephalography (EEG) develop measures of gain control that are objective, applicable to young children and those with neurodevelopmental conditions, and translatable across species. Levin and her team plan to begin by developing a series of paradigms, across two sensory modalities (somatosensory and auditory), that use EEG-based measures to detect context-dependent modulation. They will initially adapt these paradigms in an iterative manner, to maximize tolerability among young children (both typically developing and those with ASD) and to ensure they capture the target information about gain control. They will then use these paradigms to assess gain control in three- and four-year-olds with ASD (n=25) compared to typically developing children (n=25).
This pilot study aims to serve as a first step towards the development of accessible translational biomarkers relevant to a broad spectrum of individuals with ASD and animal models thereof, and toward use of such biomarkers to enhance understanding of mechanisms underlying ASD.