Sensory Processing Disorder in Autism: Unlocking the Senses
By Jenine Precious Catudio
This issue of NASET’s Autism Spectrum Disorder Series was written by Jenine Precious Catudi. Sensory Processing Disorder (SPD) is frequently observed in individuals with Autism Spectrum Disorder (ASD), significantly impacting their functioning and learning. While not exclusive to ASD, SPD tends to be more severe in this population. Studies linking ASD to SPD are increasing, enhancing awareness of this correlation among educators and researchers. This paper explores the intricate relationship between ASD and SPD, elucidating neurobiological mechanisms and proposing strategies to support individuals with autism in educational settings. Utilizing an understanding of sensory needs can benefit both ASD and neurotypical peers, emphasizing the importance of tailored classroom structures and routines. Additionally, educators can utilize sensory needs as leverage when teaching new skills, promoting optimal learning experiences. Practical suggestions for creating sensory-responsive environments in special education classrooms are provided to empower educators in fostering inclusive and supportive learning environments for students with ASD.
Abstract
Sensory Processing Disorder (SPD) is frequently observed in individuals with Autism Spectrum Disorder (ASD), significantly impacting their functioning and learning. While not exclusive to ASD, SPD tends to be more severe in this population. Studies linking ASD to SPD are increasing, enhancing awareness of this correlation among educators and researchers. This paper explores the intricate relationship between ASD and SPD, elucidating neurobiological mechanisms and proposing strategies to support individuals with autism in educational settings. Utilizing an understanding of sensory needs can benefit both ASD and neurotypical peers, emphasizing the importance of tailored classroom structures and routines. Additionally, educators can utilize sensory needs as leverage when teaching new skills, promoting optimal learning experiences. Practical suggestions for creating sensory-responsive environments in special education classrooms are provided to empower educators in fostering inclusive and supportive learning environments for students with ASD.
Introduction
Sensory Processing Disorder (SPD) is prevalent among children diagnosed with autism and Attention Deficit Hyperactivity Disorder (ADHD). Despite its significance, SPD remains relatively overlooked in clinical and educational settings due to limited awareness and research gaps. While studies have been conducted, criticisms regarding their methodologies and sample sizes persist. Autism, a complex condition in itself, frequently intertwines with SPD, posing challenges in diagnosis and treatment.
A pivotal 2013 study conducted by the University of California San Francisco (UCSF) shed light on the biological underpinnings of SPD. Utilizing imaging techniques, the study identified abnormal white matter in SPD subjects, impacting auditory, visual, and somatosensory systems crucial for sensory processing. Unlike children solely diagnosed with ADHD or autism spectrum disorders, those with SPD exhibited distinct abnormalities in different brain regions, suggesting a unique neuroanatomical basis for SPD (Murkhejee et al., 2013).
The impact of sensory issues on learning cannot be overstated, especially for students on the autism spectrum. Variations in sensory processing can significantly influence how individuals perceive and interact with their environment, often manifesting as sensory sensitivities or seeking behaviors. These challenges pose notable obstacles to various aspects of learning, highlighting the urgent need for tailored educational approaches to support individuals with SPD. This paper aims to delve into the intricate relationship between SPD and ASD, elucidating neurobiological mechanisms, exploring sensory perceptual issues, and proposing strategies for creating sensory-responsive educational environments to support individuals with autism.
Sensory Processing in Autism: Insights from Early Research and Ayres’ Perspective
Early autism research, pioneered by Kanner (1943) and Asperger (1944), highlighted the atypical sensory responses exhibited by children with ASD across various sensory modalities. Bergman and Escalona (1949) proposed a sensory hypothesis, suggesting that heightened sensory sensitivity in children with ASD leads to defensive strategies against sensory overload, contributing to developmental distortions characteristic of autism.
Pioneer research underscored the crucial role of sensory processing in overall development and function (Ayres, 1972) Although this study did not specifically focus on autism, sensory integration theory, upon which the study was based, has proven influential in understanding individuals with ASD. According to Ayres’ theory, sensory processing difficulties can contribute to challenges in motor coordination, attention, emotional regulation, and social interaction, frequently observed in individuals with ASD. Many researchers and practitioners have utilized Ayres’ principles of sensory integration to design interventions tailored to the sensory needs of individuals with autism. These interventions aim to facilitate better processing and integration of sensory information, thereby enhancing overall functioning and quality of life.
Ayres’ perspective highlights the importance of addressing sensory processing issues in individuals with autism and underscores the potential benefits of sensory integration therapy as part of comprehensive intervention approaches for individuals on the autism spectrum.
Exploring the Nexus of Sensory Perceptual Issues and Autistic Behaviors
Restricted and repetitive patterns of behavior represent one of the five criteria for diagnosing Autism Spectrum Disorder (ASD) according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). These patterns encompass stereotyped or repetitive motor movements, such as lining up toys or engaging in echolalia, as well as insistence on sameness, inflexible adherence to routines, and ritualized behaviors. Additionally, individuals with ASD may exhibit highly restricted, fixated interests that are abnormal in intensity or focus, and they may demonstrate hyper- or hypo-reactivity to sensory input or display unusual interests in sensory aspects of the environment. This section will focus on three of these patterns—self-stimulatory behavior, other repetitive behaviors, and pain insensitivity—and examine their correlation to sensory processing in individuals with ASD.
Self-Stimulatory Behavior. Sensory processing issues are closely intertwined with autism spectrum disorders. One distinguishing factor between children on the spectrum and their neurotypical counterparts is the prevalence of self-stimulatory (stimming) behaviors, including hand flapping, rocking, and repetitive vocalizations. While not universal, these behaviors predominantly manifest in children with ASD and are indicative of their distinct sensory perceptions. Previous research on self-stimulation (Koegel & Covert, 1972) suggests that when teaching a child with ASD, it is essential to ensure that the student is not excessively engaged in self-stimulatory behavior. However, the same studies indicate that self-stimulatory behavior can serve as a highly motivating reward for students with ASD, to the extent that they may be a higher preferred reinforcement than food.
Other Repetitive Behaviors, Restricted Interests and Insistence on Sameness. A recent study by Schulz and Stevenson (2019) revealed a clear connection between sensory hypersensitivity and repetitive behaviors. Interestingly, this association was not limited to individuals with autism spectrum disorder (ASD) but was also observed in their typically developing peers of similar mental age. Thus, while these findings confirm the link between sensory hypersensitivity and repetitive behaviors in ASD, they also suggest that this connection extends to the broader population. In ASD, all measures of hypersensitivity and repetitive behaviors were found to be more severe compared to typically developing peers. The research also discovered that this connection exists across different sensory modalities as well as specific types of repetitive behaviors. These behaviors include doing repetitive motor movements, rigidity and adherence to routines, preoccupation with restricted patterns of interests, and unusual sensory preferences.
Pain Insensitivity. Insensitivity to pain is observed in many individuals with ASD. Stern and Schachter (1953) documented cases where children with ASD displayed an alarming lack of perception of danger, corroborated by recent studies indicating hypersensitivity to pain in individuals on the autism spectrum (Gu & Zhou, 2017). Recent experimental study found that people with autism tend to be more sensitive to both everyday sensations and experimental pain. This heightened sensitivity to pain was linked to the severity of autism symptoms. The researchers also discovered that individuals with autism were better at blocking out sudden bursts of pain, but not as effective at blocking long-lasting pain. This suggests that there might be an imbalance in how their brains process pain signals. (Hoffman,et. al, 2023) Overall, these findings challenge the idea that people with autism don’t feel pain or aren’t bothered by it. It’s important for caregivers to be aware of this sensitivity to pain in individuals with autism.
Conclusion
While sensory processing issues are not exclusive to ASD, SPD often appears more severe in individuals on the autism spectrum. Studies correlating ASD to SPD are increasing, leading to greater awareness of this association. As educators, leveraging this understanding can benefit not only students with ASD but also their neurotypical peers. Optimal learning for students with SPD, ASD, or both, relies on classroom structures and routines that address their specific needs. Teachers should ensure that students are not exhibiting repetitive behaviors during instruction, as this can block out additional sensory input and negatively impact their learning. With that in mind, educators can use sensory needs as leverage when teaching new skills. For example, allowing a student to engage in a preferred self-stimulatory activity, such as spinning a fidget, can serve as a reinforcer or reward when the student correctly responds during one-on-one instruction.
Designing a Sensory-Responsive Environment for Special Education Classrooms
Creating an effective learning environment that addresses the sensory needs of students is crucial for facilitating academic and social development. While conventional classrooms prioritize factors such as lighting, acoustics, and seating arrangements, special education classrooms catering to individuals with ASD require additional considerations due to their heightened susceptibility to sensory processing issues. Given that sensory experiences can significantly impact behavior, it is essential to design classrooms with this in mind, particularly for students on the autism spectrum.
Educators must take proactive steps to research and implement strategies that accommodate the unique sensory needs of students with ASD. By creating an environment that recognizes and addresses sensory sensitivities, educators empower individuals with ASD to effectively navigate their sensory experiences, thereby promoting their overall learning and well-being.
Below are some suggestions considering the content of this literature review:
1. Sensory-Friendly Classroom Design: Consider the sensory aspects of the classroom environment, including lighting, noise levels, and visual clutter. Use soft lighting, minimize auditory distractions, and maintain a clutter-free space to create a calm and focused atmosphere.
2. Flexible Seating Options: Offer a variety of seating options to accommodate different sensory preferences. Some students may prefer sitting on a cushioned chair, while others may benefit from a rocking chair or a bean bag. Providing choice empowers students to select the seating option that helps them stay focused and comfortable.
3. Visual Supports: Use visual aids such as visual schedules, picture cues, and visual timers to support understanding and communication. Visual supports can help students anticipate transitions and navigate daily routines, reducing anxiety and promoting independence.
4. Sensory Break Areas: Designate a sensory-friendly area where students can take breaks and regulate their sensory input. This area should include tools and resources such as weighted blankets, fidget toys, and sensory bins to help students self-regulate and manage sensory overload.
5. Individualized Sensory Plans: Work with each student to develop individualized sensory plans that outline their specific sensory preferences and needs. Collaborate with occupational therapists and other professionals to identify sensory triggers and develop strategies to support each student’s unique sensory profile.
6. Safety Considerations: Regularly inspect the classroom environment for potential hazards and make necessary modifications to ensure accessibility and safety. Secure furniture, eliminate clutter, and provide clear pathways to prevent accidents or injuries
By implementing these strategies and fostering a sensory-friendly classroom environment, educators can create an inclusive and supportive learning environment where students with ASD can thrive academically, socially, and emotionally.
References
American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., Text Revision).
Asperger, H. (1991). ‘Autistic psychopathy’ in childhood (U. Frith, Trans.). In U. Frith (Ed.), Autism and Asperger syndrome (pp. 37–92).
Ayres, A. J. (1972). Sensory integration and learning disorders. Western Psychological Services.
Bergman, R. L., & Escalona, S. K. (1949). Sensory-integrative dysfunction in psychotic children. American Journal of Orthopsychiatry, 19, 454-470.
Gu, X., & Zhou, T. (2017). Brain mechanisms underlying abnormal pain processing in autism spectrum disorder. *National Science Review, 4,* 735–757.
Hoffman, T., Bar-Shalita, T., Granovsky, Y., Gal, E., Kalingel-Levi, M., Dori, Y., Buxbaum, C., Yarovinsky, N., & Weissman-Fogel, I. (2023). Indifference or hypersensitivity? Solving the riddle of the pain profile in individuals with autism. Pain, 164(4), 791–803
Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child, 2,217–250.
Koegel, R. L., & Covert, A. (1972). The relationship of self-stimulation to learning in autistic children. Journal of Applied Behavior Analysis, 5(4), 381-387.
Murkhejee, N., et al. (2013). Biological underpinnings of sensory processing disorder: A review and a new framework for research. Frontiers in Neuroscience, 7, 1-12.
Schulz, S., & Stevenson, R.A. (2018). Sensory hypersensitivity predicts repetitive behaviours in autistic and typically-developing children. Autism, 23, 1028 – 1041.
Stern, M. P., & Schachter, M. (1953). Sensory deprivation in autistic children. *American Journal of Orthopsychiatry, 23,* 80–95.
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