Hearing loss occurs when signals about sound fail to reach the brain. Normally sound (vibration) is captured by the ear, travels down the ear canal to the inner ear where very sensitive hair cells translate the sound waves into signals which are carried by nerves to the brain. There are two basic types of hearing loss:
- Sensorineural hearing loss is caused by damage to the sensitive hair cells inside the inner ear or damage to the auditory nerve. This occurs naturally with age or as a result of injury or damage, often though noise. It is generally irreversible.
- Conductive hearing loss happens when sounds are unable to pass from your outer ear to your inner ear, often because of a blockage such as earwax or glue ear, or because of an infection or swelling. It can often be reversed by dealing with the obstruction.
More detail on the causes of hearing loss is available on the NHS Choices website.
78% of musicians who told us they had suffered hearing loss in our survey attributed it at least in part to their work as a musician. That is why we are particularly interested in understanding and preventing noise-induced hearing loss. How it works is very simple - the sheer force of the energy contained in loud sounds reaching the hair cells in the inner ear batters them until they are destroyed. Once destroyed or damaged they do not grow back.
There are two main variables that determine whether noise is threatening to your hearing – how loud it is when it reaches you and how long you are exposed to it. (Technically there is a third variable – the energy contained in the sound – but this is significantly harder to measure and manage in most situations).
The charts belowshow how long it’s safe to be exposed to a particular loudness for and some examples of what particular decibel levels mean in practice. Notice that safe exposure times halve with every three decibel increase in loudness. Any sound above 118 dB can cause instant hearing damage.