The Balance System
In order to maintain our balance our brain joins information from our eyes and balance organs with what we feel through our joints, muscles and pressure sensors throughout our body.
Our balance organs within each of our ears detect movement. Each balance organ is made up of three curved fluid-filled tubes called the semicircular canals. As you move your head, the fluid within the semicircular canals moves sending signals to your brain about how fast and how far you have moved. Each canal is aligned to detect movement in a different direction.
What is dizziness?
The word dizziness can be used to describe a wide range of symptoms, from severe spinning sensation or visual disturbance (vertigo) to mild light-headedness. When the information from our balance organs doesn’t fit together with the information from our eyes and other parts of our body we feel dizzy. Dizziness is a symptom and not a disease, and there may be many causes.
Videonystagmography (VNG) is used to assess patients with dizziness and balance problems.
Our eyes and balance organs are closely linked to provide us with clear vision as we move. Therefore we can use your eye movements to find out how well your balance organs are working. Video goggles are placed over your eyes to allow us to record your eye movements in different situations:
- You will be asked to look at stationary, and then moving targets.
- Your head and body will be placed in different positions to see if dizziness occurs
- Warm and cool water will be run into your ear canals. The change in temperature stimulates the ears balance organ allowing us to check how well it is working.
- Your consultant may request all, or parts of the test depending on your symptoms.
A VNG test is non-invasive and essentially harmless, but may cause an artificial dizziness sensation, which varies for different people. However any dizziness will not last more than a couple of minutes, and will not affect your present condition. The test takes place under controlled conditions, and will help your consultant with their diagnosis of your present condition.
Posturography will tell your consultant what information you rely on most to maintain your balance, and which may be giving you problems.
If your consultant requests this test you will be asked to stand on a small platform, and control your balance under various conditions:
- Standing on a firm surface looking straight ahead.
- Standing on a firm surface with your eyes closed.
- Standing on a soft surface looking straight ahead.
- Standing on a soft surface with your eyes closed.
The test measures how much your body sways in each situation. We may also test how far you are able to lean your body in different directions without losing your balance. During the test precautions are taken to ensure your safety, a harness is used to prevent you from falling.
Your consultant may ask for your blood pressure to be recorded. Changes in blood pressure can cause dizziness, as well as changes in vision and discomfort in the head and neck area. This typically happens when moving from lying or sitting to a standing position. You will be asked to lie on a couch for 10 minutes, and your blood pressure will be recorded. You will then be asked to stand and this measurement will be repeated.
Certain substances can influence the body’s response to the tests, and make them inaccurate. To enable us to gain all the necessary test information, please DO NOT TAKE any of the following for a period of 48 HOURS prior to your appointment:
Do not discontinue epilepsy, heart or blood pressure medication, or any other medication not in the list above.
For your comfort we also recommend:
- You do not consume a large meal prior to testing, as you will be moving around a lot.
- You wear comfortable and loose fitting clothes, preferably trousers.
- If you wear glasses, please bring them with you.
- Bring a relative or friend with you who can drive you home, if required.
In order to maintain our balance our brain combines information from our eyes and balance organs with what we feel through our joints, muscles and pressure sensors through our body.
Symptoms of dizziness often occur because of a difference between the left and right balance organs within our ears. A number of mechanisms within the brain work to improve the balance system, using information from our eyes and our body to compensate for the bad information coming from our balance organs. Over time the brain can learn to make use of the changed signals coming from the balance organs and symptoms of dizziness will gradually disappear. This process is known as ‘vestibular compensation’.
One way of helping this process of compensation is by doing ‘vestibular exercises’, which involve movements of the eyes, head and body. The exercises are designed to produce some dizziness, this means that the brain is detecting a difference between the balance organs and is working to compensate for it. The exercises should be done three times a day for three minutes.
In order for vestibular compensation to occur you must experience dizziness. Therefore if everyday activities cause some dizziness, do not stop doing them as this will help in your recovery. However do not perform activities that will make you dizzy to such an extent that you become unwell or exhausted.