Subdivision of Sensory Processing Disorder (SPD)

Written by Tricia Au

Imagine SPD as a giant tree with a lot of branches, these branches represent the subdivisions of SPD. You might be wondering why is this relevant to me? Having the awareness and knowledge of SPD in general is only the tip of the iceberg. The subdivisions of SPD can help guide us in knowing what specific challenge your child is facing so you are better prepared to strategically implement the appropriate support and guidance for your child.

Subdivisions of Sensory Processing Disorder (SPD)

Sensory Modulation Disorder (SMD)

SMD looks into the regulation of sensory information. For example: A child may hold onto a light bulb without responding to the heat immediately, it may take the child a few seconds later to react to the stimulation but by then the child would have been badly burned from the heat of the light bulb. Children who are facing SMD have difficulty converting sensory information into appropriate behaviours that correlates with the nature of the sensory message.

Sensory Over Responding

  • Sensitive to sensory input

  • Detects sensation easily and intensely

  • Child may feel as if they’re constantly being blasted with sensory information through the different senses

  • It is also known as “sensory defensiveness”

  • Child may withdraw from having someone touch them or they may close their ears to loud noises

Sensory Under Responsive

  • Child may require a longer time to respond to sensory messages

  • Often not aware of what is occurring around him/her, for instance, may not notice when someone touches him/her

  • Child doesn’t react when seriously hurt and is not fazed by minor injuries

  • Child often is not aware of his/her body sensations, for instance hunger, hot or cold

  • Is often touched to gain attention, for instance a tap on the shoulder or spoken loudly to gain attention

Sensory Craving

  • Child seeks sensory input, may go to the point of an uncontrollable desire

  • Feels the need to constantly be active. For example, moving, running, jumping, bumping, crashing, etc

  • Enjoys spinning, rolling, swinging

  • Likes to touch objects or touches/invade other people’s space

  • Would taste or smell the object or toy

Sensory-Based Motor Disorder (SBMD)

SBMD refers to the responsiveness of the child based on the sensory information received. There are two subtypes under SBMD, which are Postural Disorder and Dyspraxia.

Postural Disorder

  • Their core trunk has poor muscle tone, having a strong core trunk helps with stabilizing your shoulders and arms

  • They get tired very easily and often seems weak

  • Finds it challenging to balance

  • Have bad posture because of a weak postural control


  • Finds it challenging to convert sensory information into physical movements

  • Feels as though the movements are unfamiliar to them especially movements with multiple steps

  • Have difficulty planning the movements in terms of the sequence of action

  • Usually seen as clumsy, awkward or accident prone

  • Prefer sedentary activities which involves little to no physical activities

Sensory Discrimination Disorder (SDD)

SDD emphasizes on the ability to interpret sensory information that comes into the brain. Often times children with SDD requires extra time to understand and respond to the sensory input. They find it challenging to distinguish between the different input of senses (visual, auditory, olfactory, tactile, gustatory, vestibular, proprioceptive, interoceptive) as quickly and naturally as others.


  • Through our visual system (eyes), we are able to gather information about our surrounding environment. It helps us determine where we are in space

  • When combined with our vestibular, proprioceptive and tactile systems, it helps us to make sense of the world as well as perform physical activities. For example, throwing a ball.

  • Enables us to understand the body language of others

  • Struggling within the visual system can lead to an individual having difficulties telling things apart. This may elicit feelings of shame, anxiety, etc


  • Processes and interprets information of what is being heard

  • Enables us to differentiate sounds that are coming from left and ride side of the ear

  • The cochlea is affiliated closely with the vestibular system, hence the combination of auditory and vestibular system plays an important role in improving one’s language skills

  • Issues with the auditory system can be really challenging for an individual, especially when the words and pitch they hear could be vastly different


  • Processes and translates information through the sense of smell

  • Information processed through the this system can quickly affect the emotion and call up memories of an individual

  • Not only does smell help us associate food better but it also helps us detect danger. For example, the smell of cookies burning will elicit an immediate reaction of quickly turning off the oven


  • Receives sensory information from our skin

  • The way information is processed and perceived from the skin plays a big role in behaviour

  • Sensory receptors in our skin identifies and differentiate texture, pressure, heat, cold and pain according to the information received

  • Subsystem in touch:

  • Protective system: reacts to stimulant that may be detected as being dangerous

  • Discriminative system: discern specific information about the traits of things that we feel. For example, hard and soft, rough and smooth, etc


  • Provides information on the taste of food and liquid

  • May not seem important but some individuals with gustatory system issues have feeding problems. Severe feeding problems can lead to the use of a feeding tube.


  • Refers to the movement of the head in relation to gravity


  • Refers to the ability to feel changes in our muscle and joints

  • Sends us sensory information when there’s movement in our joints. For example, stretching, straightening, pulling, compressing our joints

  • Gives us awareness of the position of our body parts

  • People with poor proprioceptive systems are unable to gauge their strength and often times they have difficulty feeling their muscle and joints


  • Refers to the sensations from internal sensory

  • Provides information about how our bodies feel inside

  • For instance, the feeling of hunger, thirst, bowel movement, needing to go to the toilet to pee


  • (2020). Subtypes of SPD. Retrieved from

  • Lucy, J.M. & Doris, A.F. (2007). Sensational Kids: Hope and Help for Children with Sensory Processing Disorder. TarcherPerigee.

  • Doreit, B. (2012). No Longer a Secret: Unique Common Sense Strategies for Children with Sensory or Motor Challenges. Future Horizons Incorporated

If you have not read about our posts on the introduction of Sensory Processing Disorder (SPD) , you can click on this link.

You can also check out our related posts on how parents or caregivers can help support and guide children with SPD:

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