Vestibular System Function
The primary function of the vestibular system is to tell your brain where you are in both space and time. The primary function of the brain is to control the body which it cannot do properly if it does not know where it is in space and time. The brain performs a variety of secondary functions such as thinking and processing information, but its primary role is to control the body. Due to the importance the brain puts on knowing where it is in space and time, the information produced by the vestibular system is of upmost importance to the brain.
Components of the Vestibular System
There are two main divisions of the vestibular system 1) the peripheral vestibular system, and 2) the central vestibular system.
The peripheral vestibular system is in the inner ear and consists of three fluid filled canals that inform the brain about where it is in space and whether the body is moving. Additionally, at the opening of these canals there is a membrane with crystals on it (think pebbles on top of Jello) that move with the body and inform the brain about acceleration, deceleration and position relative to gravity. With a large enough acceleration or deceleration force, like that of which a blow to the head can produce, these crystals may become dislodged and enter in to the canals. When the crystals enter the fluid filled canals it causes improper information about where the body is in space and time to the brain and the brain becomes confused. The incorrect signal to the brain causes dizziness, nausea and other symptoms.
The central vestibular system is located in the brainstem and is responsible for processing the information from the peripheral vestibular system and compares it to information from your vision to determine where we are at in space and time. When any part of this system gets disrupted, like what occurs from a large blow to the head or body, the communication between the vestibular system, the visual system and the brain is disrupted.
Effects of a Disrupted Vestibular System
The brain is very good at making up for disruptions in normal functioning and will use other systems to determine where it is in space when the vestibular system cannot. Typically, the brain will rely more heavily on vision and sensors in the joints of the body to make up for the lack of information being received from the vestibular system. When this occurs, the brain must use more energy to determine where it is in space as well as control the body leading to fatigue.
Every brain has a limit to how much energy it can use and how much stress it can tolerate. When we wake up in the morning our stress level is low, and our energy reserves are full, as the day progresses we respond to daily activities which move us closer to our maximum stress limit. In a healthy brain, we never get close to reaching our maximum stress level, which allows us to function without difficulty. With vestibular dysfunction the energy needed to just run basic brain functions is more and we function closer to our maximum stress threshold. When we meet our maximum stress threshold the brain does its best to decrease the amount of stress we expose ourselves to by giving us headaches, poor concentration and other symptoms. This occurs because your brain is too busy trying to figure out where you are in space and time and has no capacity left for thinking and processing the environment.
The most interesting part about the brain, vestibular system and visual system relationship is it gets disrupted in predictable ways and can be put back together using these three systems. At HDPT we utlize diagnostic tests to determine where in the vestibular system (central or peripheral) the dysfunction occurs and how your body is compensating to make up for the incorrect information. With this information we are then able to create an individualized treatment plan to correct the dysfunction.