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A child with sensory processing dysfunction or sensory processing disorder (SPD) has trouble with receiving, processing, and responding to sensory information. This can make life difficult in many situations. Here’s an overview of this disorder.

Table of contents

  • What is Sensory Processing Disorder?
    • Cause of Sensory Processing Disorder
    • Symptoms of SPD
    • Subtypes of Sensory Processing Disorder
    • Sensory Processing Explained: A Handbook for Parents and Educators

What is Sensory Processing Disorder?

Sensory Processing Disorder (SPD), originally called sensory integration dysfunction is when the sensory signals picked up by the nervous system are either ignored or not interpreted appropriately by the brain. A person with SPD will find it difficult to process and respond appropriately to all the incoming information from their environment, surroundings, or senses.

Cause of Sensory Processing Disorder

Sensory processing disorder (SPD) is considered a neurological disorder in which sensory information that a person receives from their senses is not recognized or organized correctly by the brain and results in an abnormal response.

The cause of sensory processing disorder is still largely unknown, though there is thought to be both a hereditary/genetic and environmental component. Those with a diagnosis of prematurity, Autism Spectrum Disorders, and other developmental disorders have an increased likelihood of sensory processing disorder.

In a recent study done by researchers at the University of California San Francisco (2016), it was suggested that there is a biological basis for sensory processing disorder. The study found that the subjects with sensory processing disorder had abnormal white matter tracts in the brain, including the connection between the left and right sides of the brain, compared to their typically developing peers.

A 2006 study also found that twins who are hypersensitive to light and sound had a strong genetic component for the cause of these sensitivities.

It should also be noted that Sensory Processing Disorder is not a recognized diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). This manual is considered the most comprehensive, current, and important resource for health professionals, social workers, and legal specialists to classify and diagnose mental disorders. It is also the same manual used to diagnose Autism Spectrum Disorder (ASD) and many other common childhood mental and developmental disabilities.

Because of this, Sensory Processing Disorder is not often “diagnosed” by the medical community. You may see it described as “sensory processing difficulties” or “sensory processing issues” in the medical setting. Doctors will often refer to Occupational Therapy to evaluate for any sensory processing concerns related to SPD. Diagnoses such as Autism, ADHD, Anxiety, and other mental health disorders can also have similar sensory processing symptoms.

Critics of sensory processing disorder believe that many children on the spectrum and with other disabilities do have sensory processing difficulties. However, they feel that there is not enough research to show sensory processing disorder needs to be a stand-alone diagnosis. They also feel that sensory integration therapy (SIT) does not have enough research behind it to prove it has a lasting effect as a form of treatment.

Even without its inclusion in the DSM-5, there are many experts who believe it should be added, based on the research mentioned above and continued research. If you talk to any parent, educator, or therapist who works with children with sensory processing disorder they can assure you that the problems and issues facing many young children with this disorder are more than real.

If you do suspect your child has a sensory processing disorder, you will need a referral to an Occupational Therapist who can evaluate for sensory processing disorder using a variety of assessments and then make recommendations for treatment. There is not one evaluation or test that can tell definitively if a child or person has a sensory processing disorder. Many of the assessments used will rely on clinical observation and parent questionnaires to help guide treatment.

Symptoms of SPD

Sensory processing can affect one sense or multiple senses depending on the individual. You will often see the two terms below when describing someone’s sensory sensitivities.

  • Hypersensitivity- Over-responsive to sensory input, including fight or flight response.
  • Hyposensitivity- Under-responsive to sensory input, they need extra input.
  • Under-Responsive – Does not recognize sensory input and may often seem like they are ignoring you or self-absorbed.

The 8 Sensory Systems involved include:

  • Tactile (touch) – this can look like sensitivity to types of clothing or fabric, textures, etc. Or it can 
  • Auditory (hearing) – sensitivity to loud noises, needing more noise in order to focus
  • Visual (sight) – sensitivity to bright lights or too many visual stimuli in the environment 
  • Gustatory (taste) – sensitivity to food textures and taste (picky eaters)
  • Olfactory (smell) – sensitivity to certain smells or craving for certain smells
  • Proprioceptive (input from the muscles and joints) – avoids big movement or craves lots of movement and input through the muscles and joints.
  • Vestibular (sense of movement) – avoids or craves constant motion such as spinning, swinging, hanging upside down, etc
  • Interoception (internal sensation) – internal sensations such as heartbeat, needing to use the restroom, etc. can be distracting or they may not realize they need to use the bathroom

This is just a very basic overview of each system. I have a lot more details on this topic in the link below.

You can read more about each sensory system in my 8 Types of Sensory Systems post here.

Sensory defensiveness will vary in different degrees of stress and anxiety with each individual. However, it is important to remember that a child with SPD may misperceive the world as dangerous, alarming, or just irritating.

Subtypes of Sensory Processing Disorder

As I mentioned above, there are 3 different categories of sensory processing disorder with 5 other subtypes under those 3 categories. Let’s take a look at each one.


Sensory modulation disorders include 3 different subsets that have to do with the body’s ability to recognize and regulate sensory input.

Sensory Over-Responsive will often look like a fight or flight response. These individuals are bombarded with even the slightest sensory input and often respond by being withdrawn or avoiding certain environments or situations. This is also referred to as being “sensory defensive”.

“Treating sensory defensiveness first reduces sensory problems and increases the effectiveness of other forms of intervention.” Sensory Defensiveness in Children Aged 2-12. Patricia Wilbarger, Med, OTR, FAOTA and Julia Leigh Walbarger, MS, OTR

Sensory Under-Responsive will often look like an individual is withdrawn or self-absorbed because they do not even recognize the sensory input around them. They have poor body awareness and may not realize they are hurt or realize something is hot or cold.

Sensory Craving sounds just like it states, this person craves sensory input and often will not stay still and is constantly on the move to find it. These children will also bump into objects.


Sensory-Based Motor Disorder (including Postural-Ocular Disorder and Dyspraxia) is when a person has difficulties controlling and stabilizing their body movements. It can also include poor vision and oculomotor (movement of the eye) control. This can show poor posture and core strength, poor balance, poor tracking of visual stimuli, poor fine motor control, poor playing skills, poor articulation, clumsiness, and difficulty with many activities of daily living (hygiene and self-care, eating, bathroom, etc).


Sensory Discrimination Disorder is when a person has difficulty understanding incoming sensory input and interpreting it appropriately. This results in poor recognition and interpretation of sensory stimuli and detection of different or similar sensations. You may see poor balance, using too much or too little force on an object, difficulty following directions, manipulating objects when out of sight, or distinguishing between similar sounds.

Sensory Processing Explained: A Handbook for Parents and Educators

In Sensory Processing Explained: A Handbook for Parents and Educators, you will find all the detailed information you need to know about sensory processing disorder, including red flags for each sensory system (one for parents and one for educators), as well as resources for supporting your child with sensory processing challenges in the home or classroom.

This book is perfect for any parent or educator wanting to learn more about supporting their child or student. It is also a great resource for professionals to use in sharing about SPD with their clients, students, and patients. 

click here to buy now

You May Also Like:

  • Ideas for Dealing with Sensitivities with Sensory Processing Disorder 
  • Calm Down Toolkit for Kids
  • Sensory Overload Signs in the Classroom
  • Sensory Processing and the Teenage Years

Sources for this post:

Acevedo, B. P., Aron, E. N., Aron, A., Sangster, M.-D., Collins, N., & Brown, L. L. (2014). The highly sensitive brain: an fMRI study of sensory processing sensitivity and response to others’ emotions. Brain and Behavior, 4(4), 580–594.

Chang Y-S, Gratiot M, Owen JP, Brandes-Aitken A, Desai SS, Hill SS, Arnett AB, Harris J, Marco EJ and Mukherjee P (2016) White Matter Microstructure is Associated with Auditory and Tactile Processing in Children with and without Sensory Processing Disorder. Front. Neuroanat. 9:169. doi: 10.3389/fnana.2015.00169

Chang Y-S, Owen JP, Desai SS, Hill SS, Arnett AB, Harris J, et al. (2014) Autism and Sensory Processing Disorders: Shared White Matter Disruption in Sensory Pathways but Divergent Connectivity in Social-Emotional Pathways. PLoS ONE 9(7): e103038.

Leigh, S. (2016, January 26). Brain’s Wiring Connected to Sensory Processing Disorder. Retrieved March 15, 2018, from

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