Sensory and Multisensory Contributions to Autism
[IDDRC Research Project]
Principal Investigator - Mark Wallace, Ph.D.
Autism spectrum disorders (ASD) are a complex set of neurodevelopmental disabilities of high incidence and that come with great individual and societal costs. In addition to the well-established deficits in social interactions and communication abilities and the presence of restricted and repetitive behaviors, ASD is frequently accompanied by alterations in sensory function–alterations now recognized in the DSM-5. However, despite the prevalence of these sensory issues, they remain poorly understood with only limited empirical characterization. Most notable in this regard is the lack of basic knowledge as to how the various sensory phenotypes map on to the better-characterized social and communicative deficits.
Although a number of studies have focused on changes in sensory processing within specific sensory modalities (e.g., vision, hearing, touch, proprioception), the prevalence of alterations across multiple sensory modalities suggests that it may be particularly meaningful to think about these deficits in a more integrated “multisensory” framework. Indeed, the generation of our perceptual gestalt is built from an active integration of information across the different sensory streams. Because the resulting perceptual representations are the building blocks for cognitive processes and functional outcomes, it is vitally important to gain greater empirical knowledge of how sensory and multisensory functions are impacted in autism. Most tangible in this regard are the core deficits in social communication, processes that are vitally dependent upon the integrity of the incoming sensory streams and the integration of information across these streams. In the current proposal we seek to provide a better view into the sensory and multisensory processing changes that accompany autism, and changes in the brain networks that subserve sensory and multisensory function. Although extraordinarily valuable in their own right, our goal is to map these sensory- and brain-based changes onto weaknesses in social communicative function, and to use this information in an effort to develop behavioral tools that could be used in remediation. The overarching conceptual framework is that alterations in sensory and multisensory function and the associated brain networks contribute to the social communication deficits that characterize ASD, and can be key targets in the development of novel remediation tools. There are three aims.
- Aim 1. to characterize visual, auditory and multisensory function in children with ASD, and to explore associations between (multi)sensory function and social and communication abilities
The aim will involve an extensive psychophysical characterization of (multi)sensory function in ASD and typically developing children using a battery of tasks, with the hypothesis that tasks indexing more “integrative” abilities will be preferentially compromised in ASD, and will be more strongly associated with social and communicative measures. Experiments are predicated on the idea that greater behavioral and perceptual variability is a defining feature in autism, and will be most evident in tasks/skills that tap integrative capacity.
- Aim 2. To describe the differences in the neural processes and networks subserving sensory and multisensory function in ASD, with a focus on a key multisensory “hub” in temporal cortex
This aim will focus on identifying the brain networks responsible for differences in sensory and multisensory performance using a powerful complementary set of EEG and fMRI approaches. This aim is framed from the perspective that activity in regions surrounding the superior temporal sulcus (STS), an area known to be affected in autism and an integral node in multisensory “binding,” will be preferentially altered in ASD. As for Aim 1, these alterations are expected to manifest as changes in the variability of neural responses in a network centered on STS and that is strongly coupled with areas of auditory and visual cortex.
- Aim 3. To translate/extend Aims I and 2 by assessing the malleability of multisensory function, providing a foundation to evaluate the utility of novel plasticity-based remediation approaches focused on improving sensory and multisensory function in ASD
Recently, we have shown a marked malleability in multisensory capabilities in typical adults–a plasticity that appears driven by neural changes centered on STS cortex. Here we seek to extend knowledge of this training-induced plasticity to ASD, focusing first on our ability to alter (multi)sensory function, but more importantly on whether such training generalizes to measures that index social and communication abilities.
These experiments hold great basic and public health relevance, in that they represent an essential step in better characterizing sensory and multisensory contributions to perception and cognition in ASD, and the neural underpinnings of these processes. This work also seeks to take advantage of the plasticity that can be enabled in these networks to improve the quality of life of those living along the autism spectrum.