3. The inner ear. The hearing part of the inner ear is called the cochlea 7KLVLVDÁXLGÀOOHGVSLUDOVWUXFWXUHWKDWLVSXVKHGRQE\WKH stirrup or stapes of the middle ear. The vibrations that are delivered to it are turned into electrical signals by specialised cells called hair cells . These electrical signals are then sent along the cochlear nerve to the brain. One of the functions of the hair cells is to amplify quiet sounds. They also try to moderate the signal generated by loud sounds. However, if sounds are very loud, these hair cells can be overwhelmed and may end up permanently damaged. This can be by a single loud sound or by repeated exposure to loud sound. These three parts enable the ear to hear a wide range of pitch of sound and a very wide range of ‘loudness’ of sound, from the gentle rustling of a leaf to the roaring jet engine of an aeroplane. However, as sounds get louder, there is a risk of these sounds damaging our ears. The risk of damage is associated with the ‘dosage’ of sound or noise received. Noise dosage The ‘dosage’ of noise exposure is dependent on two main things:
1. the ‘volume’ or intensity of the noise 2. the time or duration of the exposure to that noise.
The intensity of a noise can be measured by comparing its sound pressure (the change in air pressure caused by the sound) to that of the quietest sound that can be heard. The intensity of sound is measured in decibels (dB). Decibels are what’s called a logarithmic unit, and this means that an increase of 3dB in a sound means that the sound intensity is doubled. So a sound of 88dB is twice as intense as a sound of 85dB.
Noise exposures are a combination of the intensity and the duration of
Whilst the BTA makes every attempt to ensure the accuracy and reliability of this information, it is not a substitute for medical advice. You should always see your GP/medical professional.
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