Sensory Functions in Autism Spectrum Disorder

Researchers: Price, Marco, Schaaf, Mailloux

Detailed assessment of vision and other sensory functions in children with autism spectrum disorders (ASD) is both critical and challenging. Estimates show that over 70% of those with ASD have sensory symptoms that include hypo and hyper-reactivity to sensation, altered sensory perception and deficits in multisensory integration (Tomchek, Huebner & Dunn, 2014; Baranek, David, Poe, Stone & Watson, 2006; Russo, et al, 2010). Standardized, performance-based assessment of these sensory functions is lacking with clinicians often relying on parent or proxy report solely which may be inadequate to determine the extent and nature of sensory difficulties and their impact on performance and function (Chang, et al, 2016; Schaaf & Lane, 2015). Clinicians are not trained to manage the behavioral and sensory challenges that often accompany assessment interactions with individuals with ASD, nor are they trained to conduct salient, useful sensory assessments and to utilize assessment findings to recommend treatments (Oza, Marco, & Frieden, 2015).  Thus, clinicians often require additional training to manage the complex behaviors and sensory symptoms that often accompany ASD. This project will train clinicians (physicians and occupational therapists) with the skills and knowledge to provide vision assessment and assessment of other sensory functions for persons with ASD.  We will provide vision screenings to the autism community in the greater Philadelphia area and then extend it to other clinical sites. A project of this type, by its nature requires true team science as the principles integrate knowledge from three core specialties: ophthalmology, medicine, occupational therapy and neurology.

The Ophthalmology portion will be under the direction of Dr. Jade Price (formerly under the direction of Dr. Alex Levin, Chief of Pediatric Ophthalmology and Ocular Genetics at Wills Eye Hospital) of Wills Eye Hospital, Wills Eye is one of the top eye institutes in the country.  The program will train 10 – 12 ophthalmology residents and fellows each year with the skills needed to provide appropriate visual assessment to individuals with ASD including ocular health, visual acuity and ocular genetics and recommend treatments for these. Recognition of key diagnostic indicators via eye health and genetics may help unravel the etiology of a child’s ASD.

The occupational therapy portion of the program will be under the direction of Dr. Roseann Schaaf and Dr. Zoe Mailloux.  Dr. Mailloux is an expert in sensory assessment and treatment. Ten– 12 occupational therapists will be trained each year will be trained with the advanced-level skills and knowledge needed to provide sensory assessment using the Evaluation of Ayres Sensory Integration and the Sensory Processing Measure.  The OT trainees will also work collaboratively with ophthalmologists to facilitate vision assessments by creating a sensory story and providing adaptations to the waiting room and test environments to facilitate success.

During the course of this project, we will train over 60 clinicians with the skills and knowledge needed to provide assessment services to the ASD community; serving over 100 persons with ASD in the Greater Philadelphia Area. In subsequent years, we will extend this assessment protocol and training module to additional sites thereby influencing even a greater number of persons with ASD.

Researcher: Robertson

People with autism often describe a detail-focused perceptual style. To date, our understanding of this key aspect experience is limited to empirical studies of visual behavior using unnatural, computer-based stimuli. A basic question is whether this and other perceptual differences measured in people with autism are detectable in naturalistic viewing conditions (complex, 360°, real-world scenes). In this project, we use a combination of fMRI and immersive virtual reality, eye-tracking, and computational modeling to test prominent hypotheses of visual behavior in autism in a real-world visual setting.

Researchers: Puts, Tavassoli, Wodka

Sensory processing differences/ difficulties are now part of the most recent DSM-5 (APA, 2013) and tactile processing differences are one of the most common sensory differences in autism. Recently it has become possible to assess various aspects of low-level tactile processing via a stimulator designed by Cortical Metrics, using psychophysical approaches that have been linked GABAergic inhibitory mechanisms and tactile perception. Research findings showed that metrics such as detection threshold, or amplitude discrimination are linked to atypical cortical inhibition (Tamás, Löirincz, Simon, & Szabadics, 2003; Puts et al. 2015) and distinguish autism from other groups (Puts et al., 2015). Our next step in this research is to determine how these tactile metrics associate with the clinical features of autism, and if there are, specific subtypes based on tactile perception. Several sites have acquired data on these metrics using the same task and these datasets, when combined; provide the power to detect the relationship of these tactile perception metrics with clinical features of autism including further exploration of the GABAergic inhibitory mechanisms in autism. At the end of year 1, additional sites will be trained on the research paradigm, new devices will be purchased, and we will begin acquiring new data to add to the existing dataset in specific tasks that have shown the most promise. This large data set will provide a unique opportunity for the further exploration of the role of GABAergic inhibitory mechanisms in autism, the relationships of tactile perception and autism clinical features and higher-order autistic traits such as social interaction difficulties (via ADOS-2) and specific sensory metrics, and also examine any subgroups that might emerge. These data will be used to further inform the neurodevelopmental sensory endophenotype of ASD (see project 5); and also be useful for identifying the potential underlying neurophysiology of subtypes within the autism spectrum leading to more personalized interventions.

Researcher: H. Green

Auditory processing differences are well documented in individuals with autism spectrum disorder (APA, 2013; Bergman & Escalona, 1949; Creak, 1961; Delacato, 1974, Ornitz & Ritvo, 1968) and have been proposed to underlie language deficits in a subset of this population (Boucher, 2003; Mueller, Friederici, & Männel, 2012; Roberts et al., 2008). Neurophysiological studies support a relationship between abnormal auditory change detection timing and language impairment in school-age children with ASD (Berman, et al., 2016; Oram Cardy, Flagg, Roberts, & Roberts, 2005; Roberts et al., 2008; Roberts et al., 2011, Green, Shuffrey, & Froud, unpublished). However, studies showing such a link in children already diagnosed with ASD and language impairment are of limited diagnostic use. Although language disorders cannot currently be diagnosed until a child is “of language” age, usually at 3 or older (Centers for Disease Control and Prevention, 2012; Siegel, Pliner, Eschler, & Elliot, 1988), current neurophysiological techniques such as electroencephalography (EEG) and magnetoencephalography (MEG) have the potential to identify auditory processing differences in infants before they can actively engage in testing. Identifying early auditory processing differences could aid in identifying infants at risk for language impairment in ASD, years before behavioral methods could be used, thus leading to earlier intervention and improving language outcomes in individuals with ASD. The proposed study extends prior work and is unique and innovative in that it will use MEG recording methods to explore timing of the mismatch fields (MMF) in infants at risk for ASD. Using a longitudinal design, we will examine the relationship between auditory change detection at 6 months and language skills and presence/absence of ASD auditory sensitivity characteristics at 2.5 years (e.g., hyper- hyposensitivity to sounds). This will be the first longitudinal study exploring auditory MMF as a predictive measure of later language impairment in at-risk infants and has the potential to be of great value in early detection and treatment of language impairments in ASD as well as informing the neurodevelopmental endophenotype model in described in project 5.

Researchers: Russo, Baranek, Cascio, Woynaroski, Green

One of the hardest tasks we have as scientists in autism research is to ask the big questions. Most experimental work, whether focused on molecular mechanisms of neuron signaling or behavioral processes that define development, deals with small, manageable, operationalized pieces of the puzzle. We hope that these pieces coalesce to inform diagnosis and treatment for children with social-communication and sensory-reactivity challenges, however integrating these pieces into a coherent whole requires the synthesis of information across disciplines, modalities, and sensory domains; in short, it takes a team approach, a pool of data, and informed data analytics. This project will tackle this integration of knowledge around sensory features in ASD. First, based on current knowledge, we will build a conceptual neurodevelopmental model describing the impact of low-level sensory functions on higher-level behaviors in ASD based on the current state of knowledge across fields (year 1). This model will be published as a white paper in a highly respected science journal and serve as a guide to future research needed to build an endophenotype of sensory functions in ASD. The identification of a sensory endophenotype of autism has great potential to inform the search for genetic and neural mechanisms of ASD.  

In years, 2 and 3 of the project extant data collected across the laboratories of this program project grant will be entered into a data repository, integrated and used to carry out a series of quantitative syntheses (integrative data analyses). Findings from the quantitative synthesis will highlight aspects of the neurodevelopmental model for which we have presently amassed data and guide identification of the foci for future research. Specific research questions will be posed in a targeted, systematic and hypothesis driven manner and findings from the integrated data analysis will be published in a series of papers. As such, this project will provide a roadmap for scientific research into sensory symptoms of ASD and guide the development of a multi-site research project grant to be submitted for external funding.