Sensory processing differences are nearly universal in autism (reported in over 90% of autistic individuals per the DSM-5), but sensory processing disorder (SPD) can also occur independently. The key diagnostic difference is that autism requires social communication differences plus restricted/repetitive behaviours, while SPD involves sensory modulation difficulties without core social communication differences. In Ontario, OTs assess sensory processing while psychologists or developmental pediatricians diagnose autism.
Start with the short answer, then reveal deeper context where helpful.
Sensory processing difficulties are so common in autism that they were added to the DSM-5 diagnostic criteria in 2013 under the restricted/repetitive behaviours domain. However, not every child with sensory processing difficulties is autistic. SPD involves atypical responses to sensory input — seeking or avoiding certain textures, sounds, movements, or visual stimuli — without the social communication differences that define autism.
In Ontario, occupational therapists assess sensory processing using tools like the Sensory Processing Measure (SPM) and the Sensory Profile. Autism diagnosis requires a psychologist, developmental pediatrician, or psychiatrist using DSM-5 criteria and tools like the ADOS-2. For children with sensory concerns, a dual assessment is often recommended.
Sensory processing difficulties are so common in autism that they were added to the DSM-5 diagnostic criteria in 2013 under the restricted/repetitive behaviours domain. However, not every child with sensory processing difficulties is autistic. SPD involves atypical responses to sensory input — seeking or avoiding certain textures, sounds, movements, or visual stimuli — without the social communication differences that define autism.
The overlap creates diagnostic confusion. A child who covers their ears in loud environments, avoids certain food textures, and has difficulty with transitions might be showing sensory processing difficulties, autistic traits, or both. A comprehensive assessment by a multidisciplinary team — typically including a psychologist and occupational therapist — is needed to determine the accurate diagnosis.
In Ontario, occupational therapists assess sensory processing using tools like the Sensory Processing Measure (SPM) and the Sensory Profile. Autism diagnosis requires a psychologist, developmental pediatrician, or psychiatrist using DSM-5 criteria and tools like the ADOS-2. For children with sensory concerns, a dual assessment is often recommended.
If your child has sensory processing difficulties, OAP-funded occupational therapy can address sensory needs regardless of whether an autism diagnosis is present. If autism is suspected, pursue a formal diagnostic assessment through your pediatrician. The two assessment processes can proceed in parallel. School boards also provide OT services through special education.
APA
American Psychiatric Association — DSM-5 Diagnostic Criteria for Autism Spectrum Disorder (2013)
Research
Miller et al. (2007), "Concept Evolution in Sensory Integration: A Proposed Nosology for Diagnosis," American Journal of Occupational Therapy, 61(2), 135-140
A comprehensive autism assessment includes developmental history, standardized testing (ADOS-2, ADI-R), cognitive assessment, and clinical observation.
OT-based sensory integration therapy addresses sensory processing differences in autistic children. Learn about the evidence, OAP coverage, and what to expect.
DSM-5 classifies autism into 3 support levels. Level 1 requires support, Level 2 substantial support, Level 3 very substantial support. Learn the differences.
Commitment to Accuracy: Our data is verified against official government reports (FAO, MCCSS), peer-reviewed scientific literature, and accessible public records. Last updated: March 24, 2026.
Verified Facts
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
88,175, children are registered in the Ontario Autism Program
According to the FAO (2020 report), OAP funding covers less than one-third of estimated need at 2018-19 service levels