What is Sensory Processing Disorder?

Growing up you always heard about your 5 senses when in fact there are 8 different sensory systems. Throughout each day our nervous system takes in information through the following senses:

  1. Olfactory-smell
  2. Visual-sight
  3. Tactile-touch
  4. Auditory-sound (hearing)
  5. Gustatory-taste
  6. Proprioception-input from muscles and joints 
  7. Interoception-internal sensors indicating physiological conditions
  8. Vestibular-movement

Your body utilizes the central nervous system to take in information using all of these senses, processes it, and then responds accordingly. This process is called Sensory Integration. When your body is not able to fully process that information and respond appropriately, that is where Sensory Processing Disorder comes in. 

Sensory Processing Disorder or SPD (originally called Sensory Integration Dysfunction) is a neurological disorder in which the sensory information that the individual perceives results in abnormal responses.

There are three subtypes to sensory processing including:

1. Sensory Modulation Disorder (SMD)

2. Sensory-based Motor disorder (SBMD)

3. Sensory Discrimination Disorder (SDD)

According to the STAR Institute Sensory Modulation Disorder is when you have difficulty regulating responses to sensory stimuli (any event or object that is received by the senses and produces a response from a person).

Sensory Modulation Disorder is broken down into three different types including:

-Sensory Over-Responsiveness: Predisposition to respond too much, too soon, or for too long to sensory stimuli most people find quite tolerable. You typically see this in children that get overstimulated, overwhelmed, or agitated very easily. They do not have a normal tolerance for sensory stimulation. It might come across as a “temper tantrum” for a child when really the child is just having a difficult time regulating their sensory system and causing them to seem irritable.

Individuals with sensory over-responsivity are more sensitive to sensory stimulation than most people. Their bodies feel sensation too easily or too intensely. They might feel as if they are being constantly bombarded with information. Consequently, these people often have a “fight or flight” response to sensation, e.g. being touched unexpectedly or loud noise, a condition sometimes called “sensory defensiveness.” They may try to avoid or minimize sensations, e.g. withdraw from being touched or cover their ears to avoid loud sounds.

-Sensory Under-responsiveness: Predisposition to be unaware of sensory stimuli, to have a delay before responding, responses are muted or responds with less intensity compared to the average person. You might notice this when a child accidentally gets hurt but does not get upset or have a typical response to the pain or a very delayed response.

Individuals who are under-responsive to sensory stimuli are often quiet and passive, disregarding or not responding to stimuli of the usual intensity available in their sensory environment. They may appear withdrawn, difficult to engage and or self-absorbed because they do not detect the sensory input in their environment. Their under-responsivity to tactile and deep pressure input may lead to poor body awareness, clumsiness or movements that are not graded appropriately. These children may not perceive objects that are too hot or cold.

-Sensory craving: Driven to obtain sensory stimulation but getting the stimulation results in disorganization and does not satisfy the drive for more. You will notice this in the child that is constantly on the move climbing, jumping, or very fidgety and seems to never be able to sit still. This is because no matter how much sensory input they give their nervous system their body craves that input.

Individuals with this pattern actively seek or crave sensory stimulation and seem to have an almost insatiable desire for sensory input. They tend to be constantly moving, crashing, bumping, and/or jumping. They may “need” to touch everything and be overly affectionate, not understanding what is “their space” vs. “other’s space.” Sensory seekers are often thought to have Attention Deficit Hyperactivity Disorder (ADHD) or Attention Deficit Disorder (ADD). 
A key factor with Sensory Craving is that when the individual receives more input it does not regulate him/her; in fact, those with true craving disorders become disorganized with additional stimulation.

According to the STAR Institute Sensory-based Motor Disorder is when you have difficulty with balance, motor coordination, and the performance of skilled, non-habitual and/or habitual motor tasks.

Sensory-based Motor Disorder is broken down into two types which include:

-Postural Disorder: Impaired perception of position of body position; poorly developed movement patterns that depend on core stability. The child appears weak and/or has poor endurance. This includes the child that has difficulty engaging in typical play for a child. They would have difficulty with gross motor tasks like yoga, jumping jacks, climbing, etc.

An individual with postural disorder has difficulty stabilizing his/her body during movement or at rest in order to meet the demands of the environment or of a motor task. When postural control is good, the person can reach, push, pull, etc. and has good resistance against force. Individuals with poor postural control often do not have the body control to maintain a good standing or sitting position.

-Dyspraxia: Difficulty thinking of, planning and/or performing skilled movements especially novel movement patterns. Imagine if I told you to go into the kitchen and make a peanut butter and jelly sandwich. You would automatically start listing the steps in your head (get out the bread, peanut butter, jelly, plate and knife) and then complete them without really thinking about it. A child with dyspraxia would have a difficult time coming up with planning, organizing, and completing the task without assistance.

Individuals with Dyspraxia have trouble processing sensory information properly, resulting in problems planning and carrying out new motor actions. They may have difficulty in forming a goal or idea, planning a sequence of actions or performing new motor tasks. These individuals are clumsy, awkward, and accident-prone. They may break toys, have poor skill in ball activities or other sports, or have trouble with fine motor activities. They may prefer sedentary activities or try to hide their motor planning problem with verbalization or with fantasy play.

According to the STAR Institute Sensory Discrimination Disorder is when a child has difficulty interpreting subtle qualities of objects, places, people or other environments.

There are 8 types of Sensory Discrimination Disorder which include:

-Auditory discrimination disorder: Difficulty interpreting characteristics of sensory stimuli that is heard; (may be called Auditory Discrimination Disorder). The child may have a hard time hearing small sound differences, ex: the sound difference between “b” and “d”.

-Visual discrimination disorder: Difficulty determining/interpreting characteristics of sensory stimuli that is seen. Examples include being able to tell the difference between a circle or oval, the letters “I” and “L”, the colors red and orange, etc.

-Tactile discrimination disorder: Difficulty determining/interpreting characteristics of sensory stimuli that is felt on the skin or interpreting higher level visual/spatial characteristics of touch (includes stereognosis and graphesthesia disorders). Imagine reaching into your pocket or purse to look for your keys, being able to do this without looking is called stereognosis.

-Vestibular discrimination disorder: Difficulty interpreting characteristics of sensory stimuli, experienced through movement of the body through space or against gravity. You may see this in children that avoid going on swings, down slides, climbing on stable/moving objects, etc.

-Proprioceptive discrimination disorder: Difficulty determining/interpreting characteristics of sensory stimuli experienced through use of the muscles and joints. Imagine sitting in a chair with your eyes closed and raising your hand. You would be able to do this without looking because of proprioception. It is the awareness of your body in space.

-Gustatory discrimination disorder: Difficulty determining/interpreting characteristics of sensory stimuli that is tasted, for example tasting something and being able to tell what it is without looking.

-Olfactory discrimination disorder: Difficulty determining/interpreting characteristics of sensory stimuli that is smelled, for example being in a different room and being able to know someone is baking cookies without going into the kitchen because you know what that smell is.

-Interoception: Difficulty interpreting stimulation from internal organs (may not feel need to use the toilet or may have frequent somatic complaints such as stomach aches).

Sensory discrimination disorder refers to the process whereby specific qualities of sensory stimuli are perceived and meaning attributed to them. Discrimination means understanding accurately what is seen, heard, felt, tasted, or smelled. Individuals with Sensory Discrimination Disorder difficulties have problems determining the characteristics of sensory stimuli. The result is a poor ability to interpret or give meaning to the specific qualities of stimuli or difficulty detecting similarities and differences among stimuli. (Do I see a “B” or a “D”? Do I hear “bad” or “bat”? Do I feel a key or quarter in my pocket? Am I falling to the side or backwards?). Individuals with poor sensory discrimination may appear awkward in both gross and fine motor abilities and/or inattentive to people and objects in their environment. They may take extra time to process the important aspects of sensory stimuli.

Sensory Processing Disorder can have multiple symptoms from multiple sub types which can make it difficult to diagnose and find the right sensory diet for someone with SPD. Some common symptoms that you may see in your child include emotional, behavioral, social, attentional, or motoric problems. They may have difficulty regulating their emotions with upset or frustrated, have behavioral issues, poor social skills, difficulty with attending to a task, and poor gross motor and/or fine motor skills.

If you think your child could have Sensory Processing Disorder it's best to talk to your pediatrician about it and seek a referral for Occupational Therapy. Through skilled intervention the Occupational Therapist can help diagnose the child and create a sensory diet to help the child perform to their maximum potential in every day tasks. 

To learn more about Sensory Processing Disorder and how to help your child you can check out the book Sensational Kids by Lucy Jane Miller.



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