Sensory processing disorder incorporates three primary subtypes: sensory modulation disorder (SMD), sensory-based motor disorder (SBMD) and sensory discrimination disorder (SDD; Schoen et al., 2009). Sensory modulation disorder is defined as “the inability for an individual to organize stimuli that is being presented to them within their environment and adapt to the demands that the stimuli are putting on their body” (Schoen et al., 2009).

Research conducted by Miller et al. (2007) distinguished three subtypes within SMD: sensory over-responsivity, sensory under-responsivity, and sensory craving. Individuals who are more sensory over responsive are more sensitive to sensory stimuli (STARR Institute, 2020). Sensory over-responsivity often presents as a “fight or flight” where the individual will either withdraw from sensory stimuli or react in defense as their body feels they are experiencing an overload of stimuli (STARR Institute, 2020).

Sensory under-responsivity is when individuals show signs of being “unphased” by stimuli such as a loud bang or door slam in their environment. Individuals with sensory under responsivity tendencies might appear withdrawn from groups or disengaged, and for therapists it is important to note individuals might not respond to deep pressure or tactile input, therefore impacting their body awareness (STARR Institute, 2020).

Sensory craving describes an individual who is constantly seeking some form of input with their body, whether that be tight hugs, jumping, and/or rocking their body, they will often want to touch everything in their environment (STARR Institute, 2020). An important note to make regarding individuals with sensory craving patterns is that providing them with input will not always regulate their body and produce positive outcomes, more often than not it provides an over stimuli sensation that the individual will struggle to control (STARR Institute, 2020).