What is sensory processing disorder (SPD)?

If you’re wondering “What is sensory processing disorder?” this article addresses sensory processing disorder (SPD), a condition that is increasingly gaining recognition and understanding in recent years. 

Alternatively known as sensory integration disorder, SPD is characterized by the inability of an individual to comfortably or appropriately adapt to sensory input. 

Wearing gloves, keeping a hat on, hearing static from a radio, and eating oatmeal are examples of tasks considered distressing or impossible for individuals with sensory processing disorder. 

Sensory processing disorder tends to produce hypersensitivity or hyposensitivity in the individuals it affects. 

For individuals experiencing hypersensitivity, SPD causes a person to become overly triggered in response to normal everyday situations. While waiting in line at a coffee shop, for instance, the individual may clutch their ears upon hearing the hiss of an espresso machine. Or similarly, they may ask the lively patrons behind them to stop their “overly loud” conversation. 

On the other hand, for individuals experiencing hyposensitivity, sensory processing disorder can result in a person appearing detached or impassive. For example, the individual may stare at a wall or not respond to their friend’s questions upon entering a crowded space. 

There are different opinions on whether or not SPD should be included in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Though it is not currently recognized as a medical diagnosis, sensory processing disorder presents significant challenges, especially during childhood. 

High household tension may be caused by the child’s extreme reactions to standard situations, such as putting on clothing for the day, eating prepared meals, cooperating with siblings, and taking a bath. 

Additionally, SPD tends to affect children in the academic setting. Children with SPD may find it difficult to focus on their teachers’ instructions, as they may have challenges remaining seated during class time, finishing their meals in the cafeteria, and adjusting to substitute instructors or transitions from one subject to another.

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Signs of sensory overload

Those with sensory processing disorder consider sensory presentations to be threatening and they respond accordingly in a defensive manner. They may catastrophize and overgeneralize sensory experiences, perceiving them as harmful or threatening. In a 2022 study published by the National Library of Medicine, researchers noted that SPD produces, “extreme reactions to sensory stimuli, in a range of ‘fight, flight, or freeze’ behaviours such as aggression, withdrawal, or preoccupation with the expectation of sensory input.” 

The team further studied sensory processing disorder and found it to include the following types: under-responsive, sensory seeking/craving, and sensory over-responsive. 

Each of these labels describes an aversion to sensory input in a unique way. 

Individuals affected by sensory processing disorder who are under-responsive often appear disengaged and bored, demonstrate lethargy and low motivation, and put non-food items into their mouths. 

Those who are sensory-seeking or craving tend to display poor boundaries as they persistently cross into others’ personal areas, often with uncoordinated and incessant movements which can result in crashes or broken items. 

Those who are sensory over-responsive typically show distaste for interpersonal activities and are resistant to touching or consuming particular foods. 

Sensory processing disorder usually develops in childhood and can cause prominent problems during adolescence and adulthood. 

SPD is often identified using tools like the Sensory Profile or Sensory Processing Measure, which are validated but not diagnostic instruments.

There are several red flags for parents to look out for in their children if they are concerned about developmental delays. 

Adults who believe they may be impacted by SPD can reference the following list as they reflect on their childhood:

• Difficulty with coordination during everyday activities or sports
• Extreme pickiness with foods because of their aroma, texture, or flavor
• Delayed responses to sudden environmental changes, such as the shrill of a fire alarm, flood of sunlight into a darkened room, or slamming of car brakes
• Illogical complaints that clothing, accessories, or footwear cannot be worn due to the way it feels or fits
• Awkwardness in social settings, including the failure to return a handshake or hug, or conducting these greetings in an exaggerated manner 

Sensory integration therapy

An effective treatment for SPD is sensory integration therapy. 

While not identical, sensory integration therapy shares similarities with exposure-based treatments for anxiety, as both involve gradual and controlled engagement with distressing stimuli.

The expected outcome of this treatment is for the client to decrease their sensitivities to the sensory input involved. 

In some cases, this therapy may be so beneficial that the client begins to independently confront other stimuli. 

Sensory integration therapy is commonly offered by occupational therapists (OTs) to help clients expand their window of tolerance toward different sensations. It is otherwise known as Ayres sensory integration (ASI) due to its creation by Dr. A. Jean Ayres in the 1970s. 

The objectives of this modality include: promoting physical movement, strengthening gross and fine motor skills, teaching healthy responses to stimulation, and activating the senses. 

As of 2019, the American Academy of Pediatrics (AAP) has recognized the usefulness of ASI, but claimed that more research is needed to support its long-term benefits.

OTs are the primary providers for sensory integration therapy. Therapists whose clients have SPD concerns should refer to a licensed OT trained in sensory integration approaches.

Sensory processing disorder autism connection

Researchers have discovered a close connection between sensory processing disorder, autism, ADHD, and other neurodevelopmental disorders. 

In fact, it was reported in 2022 that 50% to 64% of children with attention-deficit/hyperactivity disorder (ADHD) also experienced atypical sensory experiences. 

Furthermore, 90% of people with autism spectrum disorder (ASD) were found to have difficulties with sensory input. 

It has long been known that individuals with autism routinely display resistance to sensory input. 

The DSM-5 includes “hyper- or hypo-reactivity to sensory input or unusual interest in sensory aspects of the environment” as one criterion under the “restricted, repetitive patterns of behavior” domain, which is one of the two core symptom domains required for an autism spectrum disorder (ASD) diagnosis.

Correlation does not equal causation, however, as some people with sensory processing disorder do not meet the criteria for autism. 

According to Autism Speaks, scientists have learned that the neural pathways in an autistic brain are “atypical” compared to those in individuals without autism. Because it is possible for someone to have SPD yet process information in a “typical” way, it would rule out the diagnosis of autism.

For clinicians searching for sensory processing disorder ICD-10 codes, currently, sensory processing disorder is not identified as a diagnosable medical condition. That being said, OTs and clinicians who wish to include these types of sensory-related challenges in their client’s treatment plan can bill F84.9 along with the notation “Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).” 

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Sensory processing sensitivity

A final element to consider when meeting clients who display or report trouble with sensory input is sensory processing sensitivity (SPS). 

Although not recognized as a medical condition, SPS is considered by general consensus to be a personality trait which intensifies an individual’s responses to certain environmental triggers. 

Those with sensory processing sensitivity have reported elevated emotional experiences and frequent overthinking before taking action. 

Studies are still emerging about its impacts, particularly since it is believed to be an inborn trait. 

Sensory assessment checklist

A useful resource for clinicians, parents, and teachers who are assessing for SPD is a sensory assessment checklist. 

Versions of this checklist are available online and differ slightly depending on the evaluator’s role and client’s age. Some are geared toward the individual’s responses in an academic setting and others are focused on young toddlers or adolescents. 

Areas of evaluation involve the person’s sense of body and movement, attitude towards smell and taste, and comfort with touch. 

Conclusion

Therapists, OTs, and clinicians who discover their client’s sensitivity to sensory input are wise to administer assessments early on to evaluate for sensory processing disorder. 

Use all the available resources to gather your data, including parental feedback, the client’s self-reports, clinical observations, and sensory assessment checklists. 

Though SPD is not recognized as a standalone diagnosis in the DSM-5 or ICD-10, clinicians can still assess for sensory processing differences and collaborate with occupational therapists to provide supportive interventions. In cases where SPD symptoms overlap with conditions such as ASD, appropriate ICD-10 codes like F84.0 may be used when clinically justified.

Sources

• Autism Speaks. “What is SPD?”  
• Choosing Therapy. (2024) “Sensory Processing Disorder (SPD): Signs, Symptoms, & Treatments.” 
• SimplePractice, ICD Code Library. (2025) ICD-10-CM Diagnosis Code F84
• Healthline. “How Does Sensory Integration Therapy Work?”
• Brain Sciences. (2022) “Sensory Processing Disorders in Children and Adolescents: Taking Stock of Assessment and Novel Therapeutic Tools” 
• Sensational Brain. (2022) Sensory Symptoms Checklist: Adolescent Version 
• Sensory Smarts, Sensory Checklist 

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