The Sensory Show 002: What is Sensory Processing Disorder?
Welcome to the world of Sensory Processing Disorder! This is an important introduction episode where I explain the terms Sensory Integration and Sensory Processing Disorder (SPD) in detail for everyone to understand. This information can be shared with family, friends, teachers and health care professionals interested in learning the in’s and out’s of sensory processing.
The term “sensory integration” was coined by Dr. A. Jean Ayres in the 70’s. She was an occupational therapist and a psychologist in California who studied the brain and worked with children clinically, to research how her therapy interventions helped children learn.
Sensory Integration is defined as the ability to take in, organize and processing information from the body and the environment, in order to have appropriate responses, which relates to appropriate behavior and learning abilities for people of all ages.
There are seven senses in the body that need to work efficiently in order to have good sensory processing. There are the five senses that we all learned about in school, which are: auditory (for hearing), vision (for seeing), tactile (for touch), gustatory (to taste), and olfactory (to smell). Then there are two more senses that are extremely important to the body that most people do not know about, they are: vestibular (for movement) and proprioception (which is our awareness of our muscles and joints in our body).
The brain stem is the lower part of the brain where sensory processing occurs (below the cortex of the brain- where intelligence is stored). The brain stem is not responsible for thinking skills or intelligence. Its job is to be the “automatic” part of the brain that serves as a “relay station” or a “filter” that manages incoming sensations and outgoing messages. These sensations come into the brain stem through the nerves in the body, for example: every time we see, hear, touch or move- these sensations run through the nerves in the body, get filtered through the brain stem and then get sent to the cortex of the brain, so the sensation can be recognized and identified. The cortex (intelligent part of our brain) then decides what to do with this information, and sends nerve impulses back through the brain stem, to the different parts of the body, so a person can respond to his or her environment by completing any action you can think of, such as laugh, walk, balance, talk, or write, etc… These are very basic functions of the body that we take for granted when our sensory processing works efficiently.
Each of the seven senses can, independently of each other, work well or not. They can be under-responsive in nature (which is called hyporesponsive), meaning the sensation that comes into the body through the nervous system is slow, sluggish, or like a dud firework, as I like to call it. Or, on the other end of the spectrum, they can be over-responsive (which is called hypersensitive). Hypersensitivity results when the nerves in the body detect sensation and send the information to the brain stem, and then the brainstem over-reacts and sends too many messages to the cortex of the brain, causing an exaggerated response. Everyone knows when a child is hypersensitive because these kids are over-reactive, overly emotional, highly stressed kids and/or typically the ones that have intense behavioral outbursts on a frequent basis. The level of hypersensitivity can range from mild to severe, and the more severe the response is, the more stressed you will find the parents, teachers and caretakers of these children.
The first 2 senses discussed in terms of having symptoms that are under-responsive or over-responsive on this episode are: the vestibular system and the tactile system. The other 5 senses are continued on next week’s episode. These senses are outlined in an easy to read format for you.
Vestibular System (our sense of movement):
Children who are movement seekers have a hard time sitting still, paying attention, following directions, balancing and developing strong postural muscles to support good eye-hand coordination abilities. These children often show symptoms related to attention deficit disorder and need to move their bodies intensely and often throughout their days in order to learn and pay attention.
Children who are over-responsive to movement can be fearful of swings, bicycles, or crawling as a baby and may appear to be a cautious child who rarely gets hurt. The brain stem perceives this movement to be overwhelming and overly intense, often resulting in a high level of stress or anxiety in this population.
Tactile System (our sense of touch):
An under-responsive sense of touch often results in poor safety awareness for sensing heat, cold or pain, and can make a child’s body crave touch through hugging, leaning on others, touching objects/people excessively and wanting to play rough or get messy.
An over-reactive sense of touch results in the nervous system perceiving light touch to be offensive, such as certain types of clothing, socks or shoes, hair brushing, face washing and being reactive to touch from others, often causing a child to get in trouble.
Tune in next week to hear about common symptoms reported on the other 5 senses!


