The 7 Sensory Systems (yes, 7!)

I haven't really touched on a lot of sensory related information yet, but before I do, I think it is important to review the 7 sensory systems in preparation for that.  Did I say 7?  Yes, I did.  Most people are aware of the basic 5 (vision, hearing, touch, taste and smell), but are not aware of the other 2, proprioception and vestibular.  These systems are the building blocks of the central nervous system and understanding these systems is vital for later understanding sensory processing.  The term ‘Sensory Processing’ refers to our ability to take in information through our senses (touch, movement, smell, taste, sight, hearing, balance) organize and interpret that information for our own use and then make a meaningful response.

Proprioceptive System
-proprioceptors are the neuroreceptors in tendons, muscles and joints.

-proprioceptors are a large source of sensory input because they are getting input whenever we move.

-input can vary in intensity.

-the proprioceptive system is stimulated by active movement of the body, particularly against heavy resistance, during heavy work, joint compression (pressure into a joint, weight bearing), or joint traction (pulling body away from a a joint).

-tends to have a more inhibitory (calming) effect on the nervous system.

Vestibular System
-located in the inner ear and relates us to gravity.

-gives us the sensation of the weight of our body, tells us where we are in space.

-Monitors our head and body movements in any direction.

-to be effective all parts of the system should be stimulated.  This is done by the head in a variety of positions and movement in a variety of directions.

-eyes closed stimulates increased use of this system.

-important in the development of visual skills.

My daughter (on the right) and a friend getting some vestibular and proprioceptive input on the trampoline.

Tactile System
-has 3 different receptors in the skin:  light touch (protective, alerting), discriminative touch, and those that receive info. about heat, cold and pain.

- firm, non moving touch is easier to tolerate than light or moving touch.  Anticipated touch is more acceptable than unexpected.

-deep touch preceding light touch increases tolerance for light touch.

-proprioception and vestibular stimulation help to improve tolerance to tactile stimulation.

Visual System
-The visual system is the part of the nervous system which allows a child to see.  The psychological manifestation of visual information is known as visual perception.

-The visual cortex is located in the rear of the brain above the cerebellum and is responsible for higher-level processing of a visual image.

-Visual perception is the ability to interpret information that the eyes are taking in.

-When a child has a visual processing disorder, he/she has a decreased ability to make sense of information taken in through their eyes. This is not the same as visual acuity, but is rather difficulty with  how visual information is interpreted or processed in the brain.

Auditory (hearing), Gustatory (taste) and Olfactory (smell) Systems
-  spontaneous sound production often occurs during sensory integrative treatment, particularly during vestibular stimulation (so you may hear more vocalizations or verbal output with movement activities).

-Auditory processing does not refer to how well a child can hear, it is how the brain processes/interprets  what it is hearing.

-Our gustatory system can identify at least five different taste sensations: sweet, sour, bitter, salty, and umami (the taste that identifies glutamate, which is found in chicken broth, meat extracts, and some cheeses).  These tastes, along with texture, temperature, and other sensations combine with odors from the olfactory system to produce the perception of flavor.

-The olfactory system, or sense of smell, senses and processes odors.

-Olfactory information travels to areas of the brain that oversee emotions, behavior, and memory, and also affects conscious thought.  (Have you ever smelled something and it reminded you of a memory?)  It combines with taste information in the brain to create the sensation of flavor as well.

Remember, it is our body's interpretation of the sensations from these sensory systems that allows us to interact with and make sense of the world around us.