The Vestibular System
There is an amazing system that helps us balance, orient ourselves, and move our bodies, called the vestibular system. The vestibular system is a sense in the body that detects movement based on head position. Anatomically, it is found connected to the inner ear on both sides. From the inner ear it then connects to the cerebellum, brainstem, the spine, many of the skeletal muscles, and the eyes. The vestibular system relies on other senses such as the eyes, ears, and tactile and proprioceptive senses to detect our body orientation in space and to help us move efficiently throughout the environment. It also helps the other senses do their jobs, as without proper orientation none of the other senses would be able to function.
The vestibular system is comprised of the three semicircular canals and the otoliths, on each side of the head, respectively. The canals are fluid-filled and have tiny hair-like structures that bend as the fluids move around the canals. When these hair-like structures bend, the body detects angular and rotary head movement, such as spinning. The otoliths are the two structures that detect linear movement, such as the movement of an elevator going up and down. They actually have weighted calcium carbonate crystals in them, that act as sensors, making us sensitive to the pull of gravity. In this way, we can gather information about acceleration of the head and we are tuned in to know if we are up, down, or tilted to one side.
The two sensory systems that the vestibular system primarily works with are the proprioceptive system and the eyes.
Proprioception is a sense that tells us about our body position. It works through receptors found throughout the tendons, joints, and muscles. When a muscle stretches, it sends information to the brain about its position and location in respect to the body.
For example, if you are about to lose your balance, you will flex your hips, move your trunk forward, and lift your arms up to catch yourself. This balancing act happens because the vestibular system is connected to the muscles in the neck, limbs, and trunk. When it senses that you are off balance it will send a signal to the body to rebalance.
The connection to the core muscles is important, because the core muscles serve as the body’s center of gravity, and this connection is activated for balance and to coordinate movement.
Conversely, balancing activities also activate and strengthen the core muscles for postural control.
The eyes are critical to balance as well, as vision guides usaround our environment safely. Furthermore, the vestibular system is connected to the eyes in six different locations, to help stabilize our eye gaze while the head is moving.
Vestibular Issues– Gravitational insecurity is the fear of being off the ground. For example, Billy is scared to be in an elevator, because he does not like the sensation of the elevator moving up and down. Vestibular under-responsivenessis when a child has a hard time sequencing and coordinating movements. For example,
Sam has a hard time coordinatingthe movements for dancing. Both these
issues come from the vestibular system not taking in sensory information properly.
The Importance of a Multisensory Approach–
All the sensory systems work together to help the body function. Many of the senses share some of the same nerves for activation. We can use this connection to help the senses strengthen each other. For example, if the vestibular system is underactive we can use hearing and or vision to give the vestibular system a boost by activating the same nerve that innervates the vestibular and visual or auditory system. This is known as a multi-sensory approach. Many educators are emphasizing the importance of a multisensory approach to help children acquire skills necessary for learning.