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Studies consistently find that a large majority of autistic people experience sensory processing differences. Learn what SPD is, how it affects daily life, and what supports are available in Ontario.
In brief
General information only, not a diagnosis, treatment plan, crisis service, or individual estimate. Confirm your next step with the linked source or a qualified professional.
Sensory Processing Disorder (SPD) describes a pattern of difficulties in how the brain organizes and responds to sensory input from the body and the surrounding environment. Sensory input includes not just the five traditional senses, sight, hearing, touch, smell, and taste, but also proprioception (body position and movement) and vestibular input (balance and spatial orientation).
People with SPD may be hypersensitive (over-responsive) or hyposensitive (under-responsive) to sensory stimuli, or may show a mixed pattern across different sensory domains. SPD is not a standalone diagnosis in the DSM-5, but sensory reactivity is explicitly included in the autism spectrum disorder diagnostic criteria. Occupational therapist A. Jean Ayres first described sensory integration dysfunction in the 1960s and 1970s, and research in this area has expanded significantly since.
Research consistently shows that sensory processing differences are among the most common features of autism. Estimates suggest that 69–90% of autistic individuals experience atypical sensory reactivity. For the DSM-5 revision in 2013, hyper- or hyporeactivity to sensory input was added as a core feature within the restricted, repetitive behaviors diagnostic criterion.
Sensory differences can affect daily life in serious ways for autistic people. Loud environments, fluorescent lighting, certain food textures, and unexpected physical contact can trigger significant distress, sometimes escalating to meltdowns or shutdowns. Environments designed without sensory considerations, including many schools and workplaces, create unnecessary barriers for autistic people.
Sensory differences present differently across individuals and sensory systems. The same person may be hypersensitive in some areas and hyposensitive in others.
Hypersensitive
Distress at vacuum cleaners, crowd noise, hand dryers, or sudden loud sounds
Hyposensitive
Not noticing when spoken to, preference for very loud music
Hypersensitive
Aversion to certain fabric textures, clothing tags, or light touch
Hyposensitive
High pain tolerance, not noticing temperature extremes, seeking deep pressure
Hypersensitive
Difficulty with flickering lights, bright environments, or complex visual patterns
Hyposensitive
Seeking visual input, watching spinning objects, flickering lights
Hypersensitive
Discomfort with physical activity or resistance
Hyposensitive
Crashing into furniture, heavy lifting, seeking tight hugs or weighted blankets
Hypersensitive
Motion sickness, fear of heights or movement, avoiding swings or escalators
Hyposensitive
Strong craving for spinning, swinging, and rocking
Hypersensitive
Strong reactions to food textures, cooking smells, or perfumes
Hyposensitive
Seeking strong flavors, not noticing household odors
SPD is not a stand-alone diagnostic code, so assessment usually happens through an occupational therapist rather than a physician. A referral can come from a pediatrician, family doctor, or be made directly to a private OT clinic in most of Ontario, no physician referral is legally required to see a private OT. The assessment typically combines a parent/caregiver interview, standardized sensory questionnaires (such as the Sensory Profile), and structured observation of the child engaging in play and movement tasks.
An OT assessment does not diagnose autism, only a qualified diagnostic clinician (a developmental pediatrician, psychologist, or psychiatrist) can do that. What an OT assessment produces is a sensory profile: a picture of which systems are over- or under-responsive, and a starting point for therapy goals and accommodation recommendations. Waits for private OT assessment vary by clinic; publicly funded OT through school boards is typically limited to consultation rather than a full sensory work-up.
Occupational therapy with a sensory integration (SI) approach is the primary evidence-based intervention for SPD. Trained OTs use structured, child-directed activities to challenge the nervous system in a controlled way, swings, obstacle courses, tactile bins, and proprioceptive exercises. The goal is to support the brain in processing sensory input more adaptively. Learn more about sensory integration therapy.
Environmental accommodations are equally important. Sensory accommodations do not require a clinical setting, they can be implemented at home, in school, and at work. Examples include noise-cancelling headphones, sensory corners with low lighting, fidget tools, flexible seating, and clothing from low-sensory fabric brands. A sensory diet, a schedule of targeted sensory activities throughout the day, can also help regulate the nervous system proactively.
A sensory diet is not a food diet, it is a personalized schedule of sensory activities designed by an occupational therapist to help regulate the nervous system throughout the day. Activities might include swinging before school, fidget tools during class, heavy work activities (carrying books, pushing a cart) between transitions, and quiet time with a weighted blanket after school. The goal is proactive regulation, not reactive management of overload.
Families and educators can reduce sensory stress through practical accommodations that cost little or nothing. At home: establish predictable routines, allow sensory tools at mealtimes, offer choices about clothing, and create a low-stimulation quiet space. At school: request sensory accommodations through the IEP or Individual Education Plan, advocate for sensory breaks, fidget tools, alternative seating, and access to quieter learning environments.
In Ontario, children with autism who are enrolled in school have the right to an IEP. Sensory needs can and should be documented in the IEP with specific accommodations. Families experiencing challenges with school accommodations can request an IPRC (Identification, Placement, and Review Committee) meeting. Learn more about autism supports in Ontario schools.
A meltdown or shutdown is a nervous system response to sensory overload, not defiance or a behavioural choice. During a meltdown or shutdown, the priority is safety and reducing input, not correction or discipline. Move to a quieter, dimmer space if possible, reduce demands and language, and give the person time to recover without an audience.
Seek urgent medical or mental health support if sensory distress is accompanied by self-injury, a risk of harm to others, or signs of a medical emergency (such as a head injury from crashing behaviour). This page provides general education only, it does not replace an individualized safety plan from a treating clinician, and it cannot assess any specific child or adult.
Sensory Processing Disorder (SPD) refers to difficulties in how the brain organizes and responds to sensory information from the body and environment. People with SPD may be oversensitive (hypersensitive) or undersensitive (hyposensitive) to sensory input, including touch, sound, light, smell, taste, movement, and body position.
Studies commonly report that a large majority of autistic people — as many as nine in ten in some research — experience some degree of sensory processing differences. Sensory reactivity is included in the DSM-5 diagnostic criteria for autism spectrum disorder. While SPD can occur without autism, it is extremely common among autistic individuals and often significantly impacts daily functioning.
Signs vary by sensory domain and direction of sensitivity. Hypersensitivity signs include distress at loud sounds, aversion to certain textures or fabrics, difficulty in bright or flickering light, and strong reactions to smells. Hyposensitivity signs include seeking intense sensory input (crashing into things, high pain tolerance), difficulty feeling temperature, or not noticing when clothing is uncomfortable.
Occupational therapy with a sensory integration (SI) approach is the primary evidence-based treatment for SPD. Trained OTs use structured sensory activities, swings, weighted tools, tactile and proprioceptive exercises, to support nervous system regulation. Environmental accommodations (noise-cancelling headphones, sensory-friendly classrooms, dimmed lighting) are also highly effective.
A registered occupational therapist can assess sensory processing. Referrals can be made by a pediatrician, family doctor, or obtained directly from a private OT clinic. Children with an autism diagnosis may be eligible for OT through OAP Core Clinical Services funding. School boards also provide some OT assessment through the IPRC process for children with identified exceptionalities.
Your Child's Health
Learn more about supporting your child's development while you wait.
What official government data tracks the Ontario autism waitlist?
VerifiedThe current province-wide waitlist record is the MCCSS FOI data published through the Ontario Autism Coalition data hub. As of May 2026, it shows 91,974 registered children and 22.5% with active funding agreements. Historical FAO, Auditor General, OHRC, and AccessOAP records provide separate context and should be cited for their own claims.
Source: MCCSS FOI via OAC May 2026 · Open source record
What does the WHO say about early autism intervention timing?
VerifiedThe WHO Fact Sheet on Autism Spectrum Disorders (updated Sept. 17, 2025) states that timely access to early evidence-based psychosocial interventions can improve the ability of autistic children to communicate effectively and interact socially. Dawson et al. (2010, Pediatrics; PMID 19948568) confirmed in an RCT that ESDM (Early Start Denver Model) at 18–30 months produced significant developmental gains.
Source: WHO Fact Sheet: Autism Spectrum Disorders (updated Sept. 17, 2025); Dawson et al., Pediatrics 2010 (PMID 19948568) · Open source record
Sources on this page
Key claims are paired with their source, evidence tier, and verification date so readers can inspect the public record directly.
Early Start Denver Model (ESDM) delivered to children aged 18–30 months produced significant gains in IQ, adaptive behaviour, and autism severity — some children no longer met diagnostic criteria at follow-up
Cochrane systematic review finds evidence that early intensive behavioural intervention (EIBI) may produce positive effects on adaptive behaviour and communication for young children with ASD (low certainty of evidence)
WHO recommends accessible, community-based early interventions for children with autism. Timely evidence-based psychosocial interventions improve communication and social engagement
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