What is Low Arousal and Sensory Modulation?

What is Sensory Modulation?

Sensory modulation refers to a person’s ability to create an appropriately graded response to incoming sensory stimuli (Parham & Mailloux, 2015).  For example, raising the volume of your voice in a noisy environment so people can better hear you, shading your eyes from the bright sun, or walking slowly into a lake, rather than jumping in, due to the coldness of the water.  When a person’s sensory system isn’t able to consistently generate an appropriate response it may be due to sensory modulation issues that occur in the brain when the nervous system is interpreting incoming stimuli. Two kinds of sensory modulation issues are possible: under-responsiveness or over-responsiveness.  


A person who demonstrates under-responsiveness to incoming sensory stimuli may appear not to notice important information in the world around them.  Research shows this type of sensory issue is frequently seen in individuals with Autism Spectrum Disorder and may be one of the initial identifiable features of the disorder, specifically difficulty interpreting social signals from others (Parham & Mailloux, 2015).  Under-responsiveness is typically observed as an unawareness to touch, pain, movement, taste, smells, sights, or sounds. It typically impacts multiple sensory systems, but one area may be more impacted than others.

Safety awareness is the primary concern for a child who demonstrates under-responsiveness to sensory information.  Children with these difficulties may be more likely to put themselves into dangerous situations because their bodies are not registering pain and other warning signs in the same way as a typical child.  With this in mind, it is important to ensure children are supervised during potentially dangerous activities, such as playing on a large jungle gym or riding a bike, and that you talk with your child about appropriate safety strategies.  


A person who demonstrates over-responsiveness may appear to have an overreaction to touch, movement, sounds, odors, and tastes.  The reaction may be observed as discomfort, avoidance, distractibility, and anxiety. Similar to under-responsiveness, this may happen in response to all types of sensory input or it may be specific to certain sensory systems.  Research shows over-responsiveness is very common among children with autism and often coexists with under-responsiveness (Parham & Mailloux, 2015). For example, a child may be over-responsive to certain types of stimuli (i.e. touch), but does not register other types of stimuli that peers typically notice (i.e. facial expressions).

Tactile defensiveness and gravitational insecurity are the two most common types of over-responsiveness.  Tactile defensiveness is the tendency to overreact to ordinary touch sensations (Parham & Mailloux, 2015).  Children who demonstrate tactile defensiveness may avoid self-care activities such as dressing, bathing, grooming, and eating as well as classroom activities such as finger painting, sand and water play, and crafts.  Click here to read our blog about strategies for managing grooming aversions such as resistance to hair cutting, bath time, nail trimming and tooth brushing. Gravitational insecurity is the tendency to overreact to changes in head position and movement, especially when moving backward or upward through space (Parham & Mailloux, 2015).  Fear of heights, even distances of only an inch or two, are likely to cause extreme fear or anxiety resulting in avoidance of stairs, escalators or elevators, step stools or ladders, playground equipment that moves, and uneven or unpredictable surfaces. Due to the extreme anxiety experienced by people who demonstrate over-responsiveness to sensory stimuli, it is important to present activities that are typically avoided, such as nail trimming or stair climbing, in a way that allows the child to feel safe and supported.

How Can Occupational Therapy Help?

If you suspect your child is having difficulties with sensory modulation an occupational therapist will likely complete an evaluation comprised of a standardized assessment, clinical observations, and talking with you about different over- and under-responsive behaviors you have observed in your child. Treatment will focus on providing your child with opportunities to be exposed to the different types of sensory information he/she has demonstrated difficulty generating an appropriate response to.  For example, identifying and imitating different facial expressions or swinging and sliding for gravitational insecurity. This approach is rooted in the concept of neuroplasticity, or the ability of the brain to change and restructure itself gradually over time based on ongoing activity. By providing your child with consistent opportunities to interpret the troublesome sensory information he or she will gradually be able to better generate an appropriate response as his/her brain gradually changes the way it interprets and responds to the stimuli.

Contact Chicago Occupational Therapy or call (773) 980-0300 to learn more about our services and how we can help your child flourish and grow.


Parham, L.D., & Mailloux, Z. (2015). Sensory integration. In J. Case-Smith & J.C. O’Brien (Eds.), Occupational therapy for children and adolescents (7th ed., pp. 258-303). St. Louis, MO: Elsevier.