Vertigo is a feeling of spinning. It occurs when people have a disorder of the inner ear. So what causes vertigo and dizziness?
First it is important to understand a bit about how the ear works. There are two ways in which the ear can detect the position and movement of your head.
The first is with the semicircular canals. These are curved channels full of fluid in your inner ear. The channels are lined with sensitive hairs. When your head turns the fluid stays still because of inertia. The canals move round with your head, so the hairs lining them are brushed by the fluid. This sends a signal to your brain that your head is moving. There are three canals at right-angles to each other so your brain can tell which plane your head is moving in.
The second way that the body can tell the position of the head is using tiny little stone-like structures which move about when your head moves. These are called otoliths which means 'ear stones'. These are affected by inflammation in the inner ear, leading to a feeling of being off-balance.
Now you understand how the body detects movement you will be able to understand why we sometimes feel dizzy. The first situation we will talk about is being on a roundabout. When you keep spinning round and round the fluid in the semicircular canals starts to spin too. When you stop spinning the fluid carries on moving. It brushes against the hairs and sending nerve signals to your brain telling it that you are still moving. The uncomfortable feeling and the nausea comes from the mismatch of these signals with those from your eyes. They are telling your brain that you are not moving.
The second situation is drunkenness. This can make you feel dizzy and off balance because the alcohol enters the fluid in your semicircular canals. It's density is different to water and so the fluid moves differently, making you feel dizzy.
Sometimes having a cold can cause inflammation which can lead to the problem also. This is because the inflammation changes the way that the fluid moves in the canals. It also affects the lining of the inner ear as well.
Benign Postural Vertigo, also known as BPV is a cause of dizziness. It is usually worse on sitting up and on moving the head. It is thought to be caused by the otoliths becoming detached and rattling about. It can happen after a blow to the head. There is a special movement of the head which can be performed by a specialist which can treat it. It is thought to move the otoliths into a position in the inner ear where they don't rattle around and cause the problem.
Dr Toby Bateson, MD of ZenPlugs