In order to get around in our world, our nervous system takes in information from the environment, sorts and combines it with information stored in the brain, and then makes a motor response. For children and adults with Sensory
Processing Disorder (SPD) there is a jumbling of this information. A helpful analogy is to think of the nervous system like a stream of traffic on a highway. As you have likely experienced there are often traffic jams or
congestion on the highway that prevent you from getting through. Similarly, for children and adults with SPD some neural impulses get blocked in the nervous system while other impulses get through. The end result is that the brain does not receive all of the sensory information necessary to do an effective job. One child described his experience like this: “There’s a traffic
jam of ideas in my head and they keep having accidents”.
Because of these traffic jams in the nervous system sensory information is not filtered properly in the brain stem resulting in too much or too little input. For example, children who receive too much input often have an inability to screen out stimuli causing them to constantly be overloaded. Imagine for a moment that you walked into the grocery store and every noise caught your attention. You heard the sound of the check out scanners, the buzz of the lights, the squeaky wheel on the cart a few rows over, the sound of a baby crying, and your mother asking you to go get apples. This is called sensory defensiveness in which the child avoids, withdraws, or becomes disorganized in response to non-noxious routine sensory stimuli. Sensory defensiveness can contribute to an increased activity level and increased distractibility in busy environments where the child becomes bombarded with more and more stimuli. The child orients to all stimuli rather than being able to filter out what is irrelevant. This leads to the child being in a fight or flight mode as they attempt to protect their system by moving away from stimuli or by reacting in an aggressive manner. In order to help themselves self- regulate, children will often fidget, move around, or in more significant cases have emotional reactions such as tantrums or a
complete shutdown. It is easy to see how these children often become labeled as ADHD based on the symptoms they present.
A Child's View of Sensory Processing Disorder as Told Through his Experience