What is Tinnitus?
Tinnitus is a sound/awareness in the ears or head which is not from a external source. People experience many types of sounds such as buzzing, hiss. whistle or ring. The pitch can be low or high and vary over time.
There are two main types: subjective and objective tinnitus.
- Subjective – This can be heard by the patient only. It is by far the most common type of tinnitus.
- Objective – This can be heard by somebody examining the patient and is uncommon. It can be caused by a variety of physical effects such as spasm of the tiny muscles in the inner ear, abnormalities in the blood vessels around the ear, increased blood flow to the ear or anatomical abnormalities of the blood vessels.
What causes Tinnitus?
The following factors are known to be involved in the development of tinnitus:
- Hearing loss (either a known loss or more subtle change to the hearing)
- Exposure to a loud noise
- Injury to the ears or head
- Ear infection
- Disease of the ear
- Side effect of a medication
- Emotional stress
Whatever the trigger for tinnitus, it causes a change to the transmission of the signal going from the cochlea (the hearing organ, or the inner ear) to the part of the brain where sound is processed, known as the auditory cortex.
This means that some of the neurons, or nerve cells, in the auditory cortex do not receive signals as they used to. In some people, these neurons react by developing spontaneous ‘chatter’, which becomes synchronised to create the illusion of sound. This is called neural synchronisation. Over time, this firing pattern is strengthened and the tinnitus can become a constant sound.