Overview of the Vestibular System
One in 20 children have some type of vestibular dysfunction, while approximately one in two children with a severe/profound hearing loss have a vestibular dysfunction.2 Even children with moderate hearing levels or a unilateral hearing loss are at increased risk for vestibular dysfunction. So, what is the vestibular system, and what does it do?
Humans have eight senses. Most people can identify the original five senses: vision, hearing, smell, taste and touch. In more recent years, three senses have been added to the list: awareness of gravity and movement (vestibular), body/joint position (proprioception) and internal sensations, such as hunger and thirst (interoception). Each of these senses provides information about what the body is experiencing. Information about the body or environment enters through a receptor. For example, the retina in the eye is the receptor for vision. The information is then sent to the brain to be analyzed so an appropriate response can be made. For instance, if you are walking in the woods and come upon a large rock in your path, your eye will “see” the rock and send that information to the brain. Your brain will then decide if you should walk around or climb over the rock and it sends instructions to your body to complete the task.
The vestibular system gathers information about the head’s position and movement in relation to the earth. It tells you if you are right side up, upside down, or falling over. The receptor for this information is called the vestibular apparatus and it is located deep inside the ear, next to and continuous with the cochlea. There is a vestibular apparatus for each side of the body (right and left) and each is about the size of a sugar cube. When the head/body moves (nodding, shaking, walking, jumping, twirling, etc.), the vestibular apparatus receives that information and sends it to the brain to be processed.
The main jobs of the vestibular system are to:
A. Identify the position and direction of movement of the head
B. Maintain balance
C. Keep vision clear when the head is moving
The vestibular apparatus consists of three semicircular canals and two otolith organs (utricle and saccule). The semicircular canals are positioned 90 degrees to each other, like the corner of a box. This alignment allows the vestibular apparatus to sense angular or rotational movements occurring in any direction. The utricle and saccule sense horizontal and vertical movements.
The importance of the vestibular system cannot be underestimated! Good vestibular function is critical for the development of both motor and learning skills and is necessary to keep us physically safe as we move around our world.
1. Li CM, Hoffman HJ, Ward BK, Cohen HS, Rine RM. Epidemiology of Dizziness and Balance Problems in Children in the United States: A Population-Based Study. J Pediatr. 2016;171:240-247.e241-243.
2. Jacot E, Van Den Abbeele T, Debre HR, Wiener-Vacher SR. Vestibular impairments pre- and post-cochlear implant in children. Int J Pediatr Otorhinolaryngol. 2009;73(2):209-217.
Information provided by Jeanine David Goldner, PT, DPT, MHS. Many thanks to Jeanine for sharing her wealth of professional knowledge with our staff, families and professional stakeholders!