Sensory Processing Disorder

1. What sensory processing disorder actually is

Sensory processing is the neurological work of turning raw sensory input — photons hitting the retina, sound waves hitting the cochlea, pressure on the skin, movement detected by the vestibular system — into useful internal information the brain can act on. The work happens at the brainstem, thalamus, and sensory cortices before any conscious thought is involved. In a typical nervous system most of this work is automatic and invisible. In an SPD nervous system the same work is done differently — thresholds are set higher or lower, integration across channels is harder, recovery from input takes longer, or the system actively chases input to reach a regulated state.

The word “disorder” suggests a malfunction. That framing is contested. The dominant view in ND-affirming clinical practice is that SPD is a calibration difference rather than a dysfunction — the same way that being short-sighted is a calibration difference rather than a malfunction of the eye. The person isn’t broken; their nervous system is tuned to a different setting than the average. The distress that brings most people to a clinician’s door comes from the gap between that tuning and the environment, not from the tuning itself.

That said, the gap is real and the distress is real. A child who screams every time the supermarket fluorescents fire isn’t being dramatic. An adult who can’t work in open-plan offices isn’t being difficult. The work of this guide is to take both seriously: the nervous-system reality, and the environmental mismatch that makes it disabling.

2. The eight sensory channels

School taught five senses. The current sensory-integration framework recognises eight. The three additional channels are the most important ones for SPD because they’re the ones most people don’t realise exist.

1. Sight (visual). Brightness, contrast, motion, colour, visual clutter. Over-responsive sight: fluorescents are intolerable, busy environments cause headaches, hates patterned wallpaper.
2. Sound (auditory).Volume, frequency, sudden noise, multiple simultaneous sounds. Over-responsive sound: sirens are agonising, can’t filter background noise in restaurants, school cafeterias are unbearable.
3. Touch (tactile). Light touch, deep pressure, texture, temperature. Over-responsive touch: clothing tags and seams hurt, hates light touch, refuses certain fabrics, unbearable hair-washing.
4. Taste (gustatory).Flavours, mixed textures. Over-responsive taste: very narrow food range, gags on specific textures or temperatures, can’t tolerate mixed consistencies.
5. Smell (olfactory).Strength and type of odours. Over-responsive smell: vomits at perfumes, can smell things others can’t, picky about food largely because of smell rather than taste.
6. Proprioception (body-position sense). Where limbs are in space, how much pressure to apply. Under- responsive proprioception: clumsy, crashes into furniture, grips writing implements too hard or too softly, breaks things. Seeking proprioception: loves crashing, deep pressure, tight hugs, heavy lifting, jumping.
7. Vestibular (movement and balance).Detected by the inner ear. Under-responsive vestibular: doesn’t get dizzy, loves spinning, climbs everything, slow to feel motion sickness. Over-responsive vestibular: motion-sick on short rides, hates being upside down, won’t leave the ground.
8. Interoception (internal body sensing). Detecting hunger, thirst, toilet needs, temperature, heart rate, emotional state in the body. Under-responsive interoception: doesn’t notice being hungry until they’re crashing, late toilet awareness, can’t locate emotions in the body. The least-discussed and arguably most important channel, especially for autistic and ADHD adults.

Most people with SPD show different patterns across different channels. A common autistic profile: over-responsive on sound, touch, and smell; seeking on proprioception; under-responsive on interoception. A common ADHD profile: seeking on proprioception, vestibular, and auditory; under-responsive interoception. The combinations are individual. The sensory profile test maps yours across all eight.

3. The three response patterns

Within each channel, the nervous system can sit at one of three settings — the same three response patterns that underlie SPD modulation. They’re visualised below as response curves to identical sensory input.

The visual is doing the work for the text here, but two things worth naming. First, the same person can show different patterns on different channels. Someone might be wildly over-responsive on sound and wildly under-responsive on interoception — and both can be true on the same Tuesday. Second, none of these patterns is wrong. They’re different default settings on the same fundamental nervous-system architecture, and each has adaptive value in some environment. Sensory-seekers tend to be extraordinary athletes and movement workers. Over-responsive people tend to detect threats and changes in the environment others miss. Under-responsive people tend to stay calm in chaos. The framing of these as deficits is mostly an artefact of which environment we’ve standardised on.

4. The three SPD subtypes (clinical framework)

The Miller / Ayres clinical framework that occupational therapists use names three subtypes of SPD. Most people have features across multiple subtypes; very few sit cleanly in one. Worth knowing the vocabulary because it’s what clinicians will use in reports.

• Sensory Modulation Disorder (SMD).The three response patterns described above — over-responsive, under-responsive, and sensory-seeking. By far the most- recognised and most-discussed subtype. Most SPD content online is implicitly about SMD.
• Sensory-Based Motor Disorder.Difficulty with movement planning (praxis) and postural control. This overlaps heavily with dyspraxia / Developmental Coordination Disorder. The kid who can’t plan how to dress, write legibly, ride a bike, or coordinate sequential movements.
• Sensory Discrimination Disorder.Difficulty telling sensations apart. Can’t feel whether hands are dirty by touch alone. Can’t locate body parts in space with eyes closed. Can’t distinguish similar sounds or similar textures by feel.

The clinical subtypes are diagnostically useful but the interventions are channel-specific. Whether a child has SMD or Sensory Discrimination Disorder, the work is the same: map the profile, accommodate the environment, find an OT with sensory integration certification if intervention is needed.

5. The DSM-5 controversy — honest version

When the DSM-5 was being revised, the team responsible for neurodevelopmental disorders considered including SPD as a standalone diagnosis. They did not. The reasoning, in summary: the research available at the time couldn’t reliably distinguish SPD from the sensory features of autism, ADHD, anxiety, OCD, and other conditions; the diagnostic boundaries were fuzzy; the proposed diagnostic criteria overlapped extensively with existing diagnoses. Standalone SPD did not meet their inclusion threshold.

That decision is contested. The arguments in both directions:

• For SPD as a separate diagnosis.Many kids and adults show clear sensory patterns without meeting full criteria for autism, ADHD, or anxiety. Treating them under those labels misses the picture. Occupational therapy literature has decades of consistent findings on sensory integration. The clinical reality is that people seek help for sensory issues and benefit from sensory-specific intervention. The DSM not naming it doesn’t make it unreal.
• Against SPD as a separate diagnosis.When sensory patterns appear without autism / ADHD / anxiety, the base rate is much lower than SPD advocates often suggest; most isolated sensory cases have something else going on (often subtle autism that wasn’t picked up). Treating SPD as separate risks under-diagnosing the broader condition. The interventions used for SPD work for the sensory features of autism and ADHD too, so the clinical category may not be necessary.

The honest answer is that both camps are partly right. SPD as a useful descriptive framework: yes. SPD as commonly separable from autism / ADHD: less commonly than the SPD community implies. The ND-affirming move is to take the sensory pattern seriously, accommodate accordingly, and assess for underlying autism / ADHD with an open mind. Many adults who think they have “just SPD” discover an autism or AuDHD profile on full assessment; some don’t. Both outcomes are valid.

6. SPD, autism, ADHD — the overlap

Roughly 90% of autistic kids have measurable sensory processing differences. Sensory differences are explicit in the autism diagnostic criteria (DSM-5 B.4). Most autistic adults will tell you the sensory experience is one of the defining features of autism — arguably more so than the social-communication features that dominate the diagnostic literature.

ADHD overlap is also substantial. The sensory-seeking pattern underlies a lot of ADHD hyperactivity — the nervous system is chasing input to reach an alert state. ADHD adults often describe fidgeting, chewing, foot-tapping, and noise- making as regulation strategies. ADHD under-responsiveness on interoception explains why many ADHD adults forget to eat, drink, or use the bathroom for hours when focused.

AuDHD — the combined autistic-and-ADHD profile — tends to have particularly complex sensory presentations, often with apparent contradictions (over-responsive on some channels and seeking on others, sometimes within the same modality). See our AuDHD guide for the combined profile.

The practical takeaway: if you or your child are showing sensory patterns, look at the wider picture too. The sensory profile is real and needs accommodating in either case, but recognising autism or ADHD opens different pathways (community, identity, school and workplace accommodations, medication for ADHD). Many adults arrive here looking for SPD information and discover something else they hadn’t named.

7. How SPD shows up across ages

The underlying neurology is stable but the visible presentation shifts dramatically. Parents looking for the early-childhood version often miss the same kid’s SPD ten years later because the surface has changed completely. A few representative trajectories.

Over-responsive sound, across ages

• Toddler. Screams at hairdryers, vacuums, fireworks. Covers ears in loud rooms.
• Preschool. Won’t go to birthday parties at noisy venues. Fights bath-time because of the running water.
• Elementary. School cafeteria is intolerable. Wears headphones at home. Avoids playgrounds.
• Tween. Sound-cancelling earbuds permanent. Wears Loop earplugs. Avoids social events. Headaches.
• Teen / adult. Won’t go to clubs or bars. Open-plan offices intolerable. Lives in a quiet home. Friend group selected partly for quietness.

Under-responsive interoception, across ages

• Toddler. Doesn’t ask for food until crashing. Late or unreliable toilet training. Doesn’t react to bumps.
• Preschool. Forgets to eat. “Holds it” until accidents. Doesn’t notice fevers or pain.
• Elementary. “Forgets” lunch. Hyperfocuses for hours without bathroom. Can’t identify what feeling is in the body.
• Tween. Skips meals. Dehydrates. Doesn’t feel tired until collapse. Emotions confusing.
• Adult. “Forgot to eat all day.” Burnout from missing fatigue signals. Therapy work involves learning to identify body sensations.

The same wiring across every age. The toddler version is loud and gets recognised; the adult version is quiet and gets pathologised as anxiety, depression, or burnout. The intervention is the same: explicit interoceptive awareness work, structured eating and drinking schedules, sensory- informed self-care.

8. SPD in adults

Sensory processing differences don’t go away. They get accommodated, masked, or both. The result is that adult SPD is often invisible from outside while costing enormous internal load. Most SPD content online is kid-focused, which leaves adults underserved and often unsure whether what they’re experiencing is real.

The adult SPD pattern often looks like:

• Narrow daily life. Specific clothing only (soft, seamless, certain brands). Specific food range. Quiet home. Solo or low-stim work. Predictable routines.
• Post-event recovery. Disproportionate recovery time after socially or sensorily demanding events. Weekend collapse after work weeks. Days of low capacity after holidays.
• Hidden masking exhaustion.The effort of tolerating sensory load in non-controllable environments (commute, office, family events) costs energy that non-SPD people don’t spend.
• Pathologised symptoms. Headaches, fatigue, insomnia, anxiety, depression, and burnout often have an unrecognised sensory component. Treating only the surface symptom misses the load underneath.
• Late recognition. Many adults recognise their SPD after their child is identified. Many discover an autism or AuDHD profile in the process.

Adult SPD work is mostly environmental and accommodative. Build the home as a sensory sanctuary. Choose work that matches the profile. Accept the profile rather than trying to extinguish it. Find ND-affirming therapy if pathologised symptoms have built up — see our therapy guide.

9. What works — OT and environment

The evidence base for SPD intervention has two solid pillars and a long tail of supportive practices.

Pillar one: occupational therapy with sensory integration certification

The Ayres Sensory Integration (ASI) approach is the original, most-researched intervention. It works through structured challenge activities — climbing, swinging, deep pressure, brushing, weighted equipment — that give the nervous system specific input under specific conditions. It’s evidence-based for kids; the adult evidence base is thinner but the underlying principles transfer.

What to look for in an OT:

• Sensory Integration certification (SIPT or ASI WPS certified)
• A fully-equipped sensory clinic (swings, ball pits, climbing structures)
• Identity-first language and explicit ND-affirming practice
• No ABA referrals or behaviour-protocol mindset
• Parent / adult involvement in the work, not parents in the waiting room

Pillar two: environmental accommodation

Adjusting the environment to match the sensory profile rather than forcing the profile to match the environment. This is the foundation that makes everything else work and the single most impactful change most families make. Specifics depend on the profile, but core moves:

• Lighting. Dimmer switches everywhere. Replace fluorescents with full-spectrum LED. Soft lamps not overheads.
• Sound. Noise-cancelling headphones available. Loop earplugs for sensitive contexts. Quiet recovery spaces in the home.
• Touch / clothing. Soft, seamless, predictable textures. Cut tags. Specific brands the body trusts. Weighted blankets and weighted lap pads for proprioceptive grounding.
• Food.Predictable textures. Same plates, same bowls, same temperatures. Don’t force range expansion under stress.
• Smell. Low-scent home. Unscented detergent. No air fresheners or strong cooking smells where possible.
• Recovery space. One room or corner in the home with controllable light, sound, and minimal visual clutter. Non-negotiable for high-sensory profiles.

10. What doesn’t work

A short list of common interventions that consistently fail and often cause harm.

• Pushing through sensory triggers.“He needs to learn to tolerate it.” This doesn’t build tolerance; it builds sensitisation. The nervous system associates the input with overwhelm and reacts more, not less.
• Behaviour modification for sensory reactions. Reward charts for not melting down at the supermarket train shame, not regulation. The child can’t comply with their nervous system at that intensity.
• Sensory restriction imposed on seekers. Telling a sensory-seeker to sit still and stop chewing is the equivalent of restraint. The seeking is regulation; restricting it worsens it.
• ABA-style protocols. Applied Behaviour Analysis applied to sensory issues compounds the harm. Sensory reactions are not behaviour to be extinguished.
• Generic mindfulness for severe over-responsivity. When the input is unprocessable, mindfulness adds shame. Use sensory accommodation first; mindfulness is useful once the base load is manageable.
• Brushing protocols without OT supervision. The Wilbarger brushing protocol, used without proper assessment and supervision, can worsen over-responsiveness. Only use under a certified OT.

11. Getting assessed

The assessment pathway for SPD is less standardised than for autism or ADHD because SPD isn’t in the DSM-5. Most people are assessed by an occupational therapist with sensory integration certification rather than a psychologist or psychiatrist. Typical pathway:

1. Structured screening. Sensory Profile-2 (kids), Adolescent / Adult Sensory Profile, or similar questionnaire. Maps the eight channels and three response patterns. Our free sensory profile test is a starting point.
2. Standardised observational assessment. Sensory Integration and Praxis Tests (SIPT) is the gold standard but only available from specifically certified OTs. Clinical observation of motor planning, posture, and response to graded sensory input.
3. Functional interview. Daily-life impact: school, work, social, sleep, eating, dressing.
4. Differential consideration. A good clinician will explicitly consider whether autism, ADHD, or anxiety might explain the picture. If unclear, referral for full developmental assessment is appropriate.

For school accommodation, OT reports are usually accepted even without a formal SPD diagnosis. Many schools build sensory accommodations into IEPs or 504 plans on the basis of the functional pattern rather than a specific diagnostic label. If autism or ADHD is also present, the formal diagnosis under those labels usually unlocks more support. See our diagnosis guide for the broader assessment pathway.

12. Frequently asked questions

Information only — not medical or diagnostic advice. If you suspect SPD or an underlying neurodevelopmental condition, consult an occupational therapist with sensory integration certification or an ND-affirming clinician.