First let’s look at what a vestibular system is… in simplest terms it is our balance system. Most mammals are born with a vestibular apparatus, which is comprised of three components within our ears including the utricle, the saccule, and three semicircular canals. The first two components: the utricle and the saccule detect gravity while in a vertical position (standing/sitting positions) and all linear movement. The semicircular canals detect rotational movements by how the fluid within those canals is moving. When our heads rotate to the right the inertia (force caused by the movement) makes the fluid within the canal lag behind and provides input to the receptors within the canals to send a message to our brain. With a correctly functioning system receptors in the right ear and left ear reciprocate (act opposite) each other providing the brain with inputs from both sides of our bodies. What the brain does with this information is even more technical and I won’t go into all those details in this post.
Next let’s discuss what the vestibular system does. As the brain integrates the previously discussed sensory input in the cerebellum, it sends the information to our motor cortex, and then information is sent back out of the brain down our spinal cord to our muscles and joints. When you are walking on a patch of ice and feel yourself quickly slipping our vestibular system is activated and sending inputs to our brain to pass information back out to our extremities causing a “protective righting reaction” aka throwing your arms out into interesting positions to allow you to keep your balance and not fall on your tailbone. When you are spinning in a circle your vestibular system is activated in that rotational movement causing the fluid of your inner ear to flow and hit all those receptors. You become “dizzy” because the fluid is still flowing due to the inertia. In its simplest terms our vestibular system tells us how to balance our bodies and tells us where our head is in space: upside down, right side up, lying sideways etc.
What does it look like if we have a well-functioning vestibular system? Basically we are aware of our bodies, and are able to attend to/focus on all the other sensory inputs that our brain is attempting to process. We are able to feel safe with all different kinds of movements and know that we can balance on one foot without significant fear of falling, or we are able to tolerate swinging back and forth or in circles on a swing knowing that our body is going to respond appropriately and keep us safe. We enjoy various movements like jumping, spinning, crawling, driving in a car, rolling down a hill, riding a bike, and participating in action sports.
Well, but now what happens if our vestibular system is not functioning properly you ask? Majority of vestibular systems that are out-of-whack are often overly sensitive OR under responsive. Overly sensitive vestibular systems cause symptoms such as motion sickness, car sickness, dizziness, significant fear of heights, and/or frequent bouts of loss of balance/falling often. An under responsive vestibular system commonly causes us to “seek” out prolonged vestibular input; a person may spin in circles for a long time without becoming dizzy, rocking back and forth continuously while sitting or standing, jumping/bouncing/running/crashing into objects and people. Many times people with an under responsive vestibular system have difficulty sitting still and “fidget” in their seats. It is also possible to have a vestibular system that is both over sensitive with some forms of input (linear vs rotational) and under responsive to other forms (again linear vs rotational).
Lastly, what can we do to help ourselves and those we love have a properly functioning vestibular system? This is where the Sensory Integration piece of “Vestibular Input” comes into play, finally right?! Looking at if we are working with an overly sensitive vs under responsive system is going to direct which forms of input you want to give the system. For those with an overly sensitive system we want to start with slow rhythmical linear movements in a horizontal pattern, then move to a vertical pattern, and gradually working up to a rotational pattern. Starting out just rocking back and forth while sitting or standing is a good place to start then you can graduate and try using a swing to facilitate these movements. The goal is to keep the movement rhythmical and allow the vestibular system to predict the pattern of the input to give the brain time to process the information, in-turn, promoting the development of the system. For those with an under responsive system we want to allow the person multiple times per day of at least 15 minutes of MOVEMENT, movement, and more movement. Jumping, running, spinning, rocking, flipping, doing balance activities, going on swings/slides/playground equipment, any and all yoga poses including those with inversion and changing the position of the head in relation to your body.
Finally my last thoughts for you are while we have really focused on the vestibular system and vestibular input, you cannot talk about this aspect of Sensory Integration without looking at our other systems including visual, auditory, tactile, and proprioceptive. Check back here for more entries in the Sensory Integration series that will include these systems and inputs. If you are concerned about your child’s Vestibular system and would like one of our therapists to take a look at them please contact us directly using our contact page of this website. Thank you for reading, I hope you learned something new!
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