March 12, 2019

Part 1: SPD Classifications

Category 1, Sensory Modulation Disorder

If you’re new to sensory processing disorder, I highly recommend getting some more background on our page that goes more in depth into SPD. When your loved one receives a SPD diagnosis, they may be placed in a specific category or sub-category classification based on their movements, behaviors, and signs/symptoms. These classifications are often referred to by healthcare providers, school administrators, etc. Understanding these classifications, discussed by by Carol Kranowitz, M.A (1) and Lucy Jane Miller, PHD and her co-authors (2), can provide some insight into how your child typically responds to different sensations. For example, are they overstimulated, non-responsive, or seeking more of certain types of stimulation?

In this first blog post of a four part series, we are discussing the category of Sensory Processing Disorder referred to as Sensory Modulation Disorder (SMD). Typically an individual living with SMD will display exaggerated responses or lack of response to certain sensations. They may have problems with one or more senses in several areas. Three subcategories of SMD are listed below with examples of displayed behaviors, signs, and symptoms.

Sensory Modulation Disorder (SMD) Subcategories:

  • Sensory Over-Responsivity (SOR): Avoiding touch or certain textures with clothing or food Refusal to wear certain types of clothing. Avoids certain types of movements or sudden movements. Overwhelmed by sounds, lights, or lots of movement. Avoids strong smells like ripe bananas or coffee. Refusal to eat certain food textures or temperatures (1). You may observe willful, rigid, controlling or illogical behaviors that are “unconscious physiologic reactions to sensation”.  People living with SOR can appear irritable or moody, struggling with socialization (2).
  • Sensory Under-Responsivity (SUR): Those with SUR may have a disheveled or messy appearance.  They may not notice different textures and are prone to dropping things. People with SUR appear unmotivated to move or engage in physical play, preferring instead to watch TV or read a book. They may become more motivated after moving heavy objects, whether it’s pushing, pulling, or lifting. They may appear unresponsive, staring at light, “ignoring” sounds, or seemingly looking right through objects and faces. They may enjoy rhythmic music at loud volumes. Individuals with SUR may have a poor sense of smell and taste, eating very spicy foods and seeming unfazed (1). People living with SUR may appear to be non-responsive to different sensations. They may display behaviors that appear as a lack of drive in the form of apathy or lethargy to explore new things or socialize, coming off as withdrawn or self-absorbed. These individuals are often perceived as lacking motivation or being “lazy”. As a baby he or she may have been perceived as the child that was “easy” or “didn’t fuss much”. People with SUR can also appear as clumsy, having a poor sense of body awareness (2).
  • Sensory Seeking (SS): People living with SS seem to crave large amounts of sensations such as spinning for long periods with little or no dizziness, loud noises, chewing on inedible objects, eating strong tasting or spicy foods, and looking at shiny, visually stimulating objects.  These may be the people that are ostracized socially for behaviors like restlessness, constant movement, rubbing up against or crashing into things and people, impulsive actions, lots of jumping, smelling strong odors, and/or larger amounts of seemingly impulsive affection. These actions can be seen as a form of seeking attention.  They may speak in loud voices or seek loud or crowded environments. When sensory needs are not met, behaviors can become aggressive leading to disciplinary problems at school and unfortunate labels like “instigator” or “bad influence”. Symptoms can often appear similar to those seen in attention deficit hyperactivity disorder (ADHD).  SPD and ADHD can occur separately or together (1, 2).

Why is this helpful? These lists can be a useful tool for a parent who is new to SPD and is still identifying these unique behaviors. Reviewing these classifications might help you become more aware of some the less-obvious challenges your child is experiencing. Additionally, a familiarity with these terms may help you converse with health care practitioners, school administrators, etc. If you would like more information on SPD, please see the page on our website and the other blog posts in this series to learn more about this condition.

The next step will be discovering where in the brain the disconnect is occurring. Where are the senses not processing properly? Call today to schedule a complimentary consultation with one of our brain rehabilitation specialists. Let’s uncover your child’s neurological challenges and begin targeted therapies to address the problem.


  1. Kranowitz CS, The Out-Of-Sync Child: Recognizing and Coping with Sensory Processing Disorder. 2nd ed. New York: Penguin Group; 2005.
  2. Miller LJ, Anzalone ME, Lane SJ, Cermak SA, Osten ET. Concept evolution in sensory integration: a proposed nosology for diagnosis. Am J Occup Ther. 2007 Mar-Apr;61(2):135-40.


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