Read Full Text: Toward an interdisciplinary approach to understanding sensory function in autism spectrum disorder (Free to access)
Journal: Autism Research
Year Published: 2016
Ranked 40th on our 2016-2021 list of the 100 Most Influential OT Research Articles
CEU Podcast: Understanding Sensory Function in Autism with Bryden Giving
Medical providers don’t always have all the answers—and we need to be honest with ourselves (and our patients) that we still have much to learn about human health.
While most OTs have a solid foundation on autism and sensory function, this week’s article really illuminates how far we still have to come.
The authors take 3 main assumptions that both neuroscientists and occupational therapists make regarding sensory function—and they discuss where the research stands with each one. They also make a point to call for more collaboration between the two disciplines.
I left this article feeling humbled by how much we still have to learn about sensory function and autism. Yet, I’m also in awe of the advances we have made over the past few decades—and I can only imagine what we will learn in future years!
Let’s dive in.
Why was this paper written?
While it seems obvious that researchers and practicing clinicians should work hand in hand, the reality is that they often work in silos. Hence, papers like this one are needed to bridge those professional gaps.
The authors attempt to foster collaboration by:
- Describing differences in goals, values, and approaches
- Sharing similarities in conceptual frameworks
- Reviewing current research on the aforementioned frameworks
- Pointing to future research needs
While several disciplines look at sensory function in autism, this article focused specifically on occupational therapists and neuroscientists (a discipline that focuses on psychophysics and neuro-imaging).
How the goals, values, and approaches of OT and neuroscience differ.
Although there is a growing overlap in perspectives, there are still pretty significant differences in how sensory function and treatment are approached by OT vs. neuroscience.
Here’s a brief overview of the two disciplines in how they approach autism and sensory function:
Goals, values, and approaches of neuroscientists
The primary goal of neuroscientists is to use the scientific method to accurately describe the neural basis of sensory function in those with autism.
To achieve this goal, the neuroscience community places high value on fidelity and rigor in both stimulus delivery and response measurement. Thus, environments are typically quiet, sedentary, and controlled, in order to help isolate specific senses. Measurements are objective and use tools such as electroencephalogram (EEG) or functional magnetic resonance image (fMRI).
Goals, values, and approaches of occupational therapists
The primary goal of occupational therapists is to assess how sensory differences, along with other factors, might impact daily life for those with autism.
OTs are also interested in how certain interventions might either influence sensory function or accommodate dysfunction. As always, the ultimate goal of any OT practitioner is supporting patients’ ability to engage in meaningful life activities.
For this reason, OTs focus on actively engaging clients in natural (re: less structured or sterile) environments. Outcomes are measured through standardized assessments, of course—but they’re also measured by non-standardized tests, clinical observations, caregiver reports, and tracking of individualized treatment plans.
3 shared perspectives—and where the research stands behind each one.
The article outlines 3 main perspectives that are shared by both neuroscientists and occupational therapists. I definitely encourage you to read the sections in their entirety if you are particularly interested in certain areas. There is quite a bit of complexity to this topic.
Please be cautioned: even though the perspectives are shared by both neuroscientists and OTs, you’ll see shortly that they are not yet fully supported by research; thus, they should not be regarded as hard-and-fast rules.
The perspectives are best understood as assumptions under which we’ve been operating—but that may need to change in the future.
Shared perspective #1: atypical behavioral responses to sensory stimuli are a consequence of atypical neural processing.
OTs and neuroscientists agree that neural differences in autistic people lead to altered sensation and perception. This, in turn, is thought to give rise to atypical behavioral response patterns, such as hyper- or hypo-responsiveness to sensory stimuli.
Research inroads related to perspective #1
Significant progress has been made in categorizing autistic people’s sensory differences at the neural level. Such differences have often been found via EEG and fMRI in highly controlled environments. This type of progress has contributed to the recognition of sensory features in American Psychiatric Association’s 2013 diagnostic criteria.
However, while the neural measures of altered sensory function have been well established, linking these numbers to clinical measures of sensory function has been difficult.
Or, to put it more bluntly, perspective #1 has not been confirmed by research. While there are clearly established differences at the brain level, we have yet to fully understand/measure how they affect overall function.
Two possible reasons for this were suggested:
- Perhaps our clinical measurements simply aren’t sensitive enough to really capture the link between neural differences and differences in behaviors. For example, many of our clinical assessments are self-reports. These measures are not specific enough to capture something like auditory hyper-responsiveness.
- Or, maybe perspective #1 is wrong or incomplete and needs to be modified. Perhaps the observed neural differences related to sensory processing aren’t responsible for atypical behaviors—or maybe there are other contributing factors, such as attention and arousal, that make the picture more complex.
In the future, better measurements at both the neural and clinical levels are needed.
Shared perspective #2: differences in sensory function may explain higher-level deficits in people with autism.
Both OTs and neuroscientists use a hierarchical framework for conceptualizing sensory function. They agree that sensory representations provide a foundation for higher-level areas, such as:
- Cognition
- Linguistics
- Social interactions
- Adaptive abilities
- And, ultimately, the ability to engage and participate in a meaningful life
Historically, OTs have emphasized the following hierarchy, where proximal senses formed the basis for distal senses. (And, in turn, more complex functions.) This understanding is based on the seminal work of Jean Ayres.
Proximal senses:
Vestibular
Tactile
Proprioceptive
↓
Distal Senses:
Visual
Auditory
↓
More complex functions:
Perception
Attention
Cognition
Praxis
By contrast, neuroscientists put a greater emphasis on describing individual senses. They tend to look at the neuroscience of hearing, vision, etc.
In recent years, there has been a convergence of the two disciplines, recognizing something called “multisensory integration.” The phrase describes how information from multiple systems works together in the body. The science is showing us how complex and intertwined the different senses really are. In fact, complex functions like cognition can actually influence our basic senses. In my own words, I would say that our senses, perceptions, and behaviors are better understood when viewed as an intertwined web, rather than a simple hierarchy.
Research inroads related to perspective #2
The research does indicate that auditory and visual stimuli correlate with symptom severity; poor integration of the two senses seems to correlate with more severe symptoms.
But, the emphasis here is on CORRELATION. Poor sensory integration is related to symptom severity—but the research does not yet indicate that poor sensory integration is the CAUSE of symptom severity. And, we still need more research on the proposal that sensory differences produce a cascading effect on other deficit domains.
Shared perspective #3: sensory function may be malleable with treatment.
Both OTs and neuroscience operate on the belief that sensory function in individuals with autism is susceptible to environmental influences—and this function is malleable and able to be improved with the right treatments.
And, in turn, both disciplines believe that improvements in sensory function should translate to improvements in higher-level deficits.
Research inroads related to perspective #3
The authors state that there’s still a relative lack of evidence showing that treatment improves sensory function in autistic individuals.
They point out the current controversy over whether science supports the efficacy of sensory-based intervention in children with autism. Early studies had too many methodological issues to give confidence in their findings.
More recent studies have improved in validity, and they show some promise, but the authors still state that the shared perspective relating to treatment is still tenuous and represents the most pressing need for future research.
Authors’ conclusion and recommendations
The authors call on experts from various disciplines to work together to continue to test the shared perspectives listed above. They envision the fruits of such collaboration to be better translation of research into practice and, more importantly, improved assessments and interventions for persons with autism.
3 Takeaways for OT practitioners
These are my personal takeaways, and were not mentioned in the article.
1.) It has never been easier for us to hear from neuroscientists and researchers.
At first, I was a little annoyed by the push to collaborate more with neuroscientists. It felt so impractical for many of us. After all, how many of us have neuroscience showing up to our daily practices?
But, in doing supplemental research for this article, I was actually blown away by how many relevant and easily accessible articles and podcasts are out there! From mind-bending research articles, to compelling interviews on podcasts like the Two Sides of the Spectrum podcast, it truly has never been easier to connect our work to research.
2.) Growing our understanding of the sensory system will help us better connect and communicate with autistic clients and families.
The more we understand about the sensory system, the better we can connect with our many clients with sensory system differences and/or dysfunctions.
While we may not know everything about how sensory differences impact perception and behavior, we can recognize there are differences as deep as the neural level. And, we know that we need to take the time to really listen to and understand our clients. Instead of trying to impose our understanding of the world on them, we can tune into their unique strengths and help them participate in the world in ways that are meaningful to them.
3.) This is about all of our patients—not just our autistic clients.
Sensory function can feel so complicated that we may feel tempted to shy away from understanding it. It’s easier to just leave it to our pediatric colleagues who specialize in autism. But, the reality is that there is an increasing number of human conditions where we now know that multisensory processing is disrupted. These include:
- Schizophrenia
- Dyslexia
- Post-traumatic stress disorder (PTSD)
- Traumatic brain injury
All this exciting research on sensory systems is changing how we understand the human body and brain. And, as OTs, it is our honor and our responsibility to keep up with these shifts in thought to ensure we spend every day making a difference in the lives of our patients.
Here’s the full APA citation for this article:
Cascio CJ, Woynaroski T, Baranek GT, Wallace MT. Toward an interdisciplinary approach to understanding sensory function in autism spectrum disorder. Autism Res. 2016 Sep;9(9):920-5. doi: 10.1002/aur.1612. Epub 2016 Apr 19. PMID: 27090878; PMCID: PMC5564205.
Earn one hour of continuing education by listening to the podcast on this article!!
In this podcast episode, we dive even deeper into this topic, with pediatric OT (and Club member!), Bryden Giving. You may be eligible for continuing education credit for listening to this podcast. Please read our course page for more details!
