Sensory Processing Disorder

An indepth look at the components of sensory processing disorder.

By Polly Godwin Emmons and Liz McKendry Anderson, co-authors Understanding Sensory Dysfunction

Sensations are the way that we take in information from our environment (internally and externally) and then process them to make sense of what is going on in us and around us. What makes sensory processing so complex is that it is not an all or nothing "thing." No one is really prefect at sensory processing, and most people have some ability to integrate through at least some of their senses. An example of someone who might be considered to possess good sensory processing might be an Olympic gymnast. An example of someone who might be considered to possess poor sensory processing might be an individual with severe autism. So, in essence, we are looking on a sensory integration "spectrum" - sensory processing along a continuum. To help people gain a better understanding of how sensory input is processed, professionals often break sensory processing down into different components; for example, sensory registration, sensory modulation, and sensory response. To clarify these terms, we will refer to sensory registration as the conscious or unconscious perception of one or more sensory signals; sensory modulation as the modification or alteration of the perception of a sensory signal (e.g., level of arousal) before it is processed for appropriate action; sensory response as the behavior that is driven by the integration of the registration and modulation of the sensory input. The following provides a brief look at a few examples of behaviors you might see in a child experiencing difficulties with sensory processing.

Difficulties with sensory registration: may appear under-reactive to movement or touch, can appear lethargic, may exhibit a delayed response to sensory input. Or may appear over-reactive to movement or touch, may exhibit heightened response to sensory input.

Difficulties with sensory modulation: may be upset wit changes in routine, have a high level of distractibility, have a high activity level, experience difficulty with transitions, or may appear "detached", "withdrawn", or "shutdown".

Difficulties with sensory response or "integration": may have problems with motor planning, may have a poor quality of motor responses (especially controlled motor responses and/or "protective" responses), may have poor body awareness, may have trouble coordinating both sides of the body.

Some professionals include sensory defensiveness when addressing some of the common sensory processing problems. A child showing sensory defensiveness may resist or even strongly refuse certain types of activities or touch, may appear to be very emotionally labile or "fragile," maybe considered to have "odd" or "unusual" eating habits or be considered a "picky eater" or a "difficult" child at meals.

In other theories, sensory processing has been broken down into different components. For our purposes, we prefer to break down sensory processing into the following components:

It is important to note that these components in sensory processing will be influenced by several other factors, including the modality (the channel it took), the intensity (how strong it was), the duration (how long it lasts), and the location (where it occurred) of the sensory input.

Polly Godwin Emmons and Liz McKendry Anderson are the authors of the excellent book Understanding Sensory Dysfunction. This article is excerpted with permission of Jessica Kingsley Publishers.