How do we hear?The ear is made up of 3 parts; the outer ear, the middle ear and the inner ear. Sounds is picked up by the outer ear (the pinna) and sent down the ear canal to the eardrum. Each part has a special function so we can hear. As sound is sent down the canal to the eardrum sound vibrations cause the eardrum to rock back and forth. Three tiny bones in the middle ear send the sound vibrations the inner ear which contains over 30,000 tiny hair cells. Vibrations from the middle ear cause these hair cells to move and send the signal to the brain which is interpreted as sound.
Why you should protect your hearing
Once you damage your hearing it won't come back.
With hearing loss:
- you can miss half of everything someone says, and what you can pick up requires a high level of concentration
- you tend to become stressed, frustrated, unsure and withdrawn
- you cannot pick up the soft sounds that many take for granted - a bird call, the swish of clothing, the softest breathing
- the risk of accidents and danger is increased when signals are missed - a siren, a car approaching, a knock on the door.
Why is noise hazardous to hearing?
The most vital area for normal hearing is the inner ear or cochlea. It is the area permanently damaged by excessive noise. Very loud sounds make significant vibrations inside the ear that distort and tear the very delicate membranes and structures.
Why don't we avoid loud sounds?
The inner ear does not sense sharp pain. It does not warn you. Most people think no noise pain, no danger. Wrong!
Even if loud noise does not produce any sharp pain, it may still cause you damage. If you are continually exposed to loud noise (e.g. 90 decibels) over a day it can produce permanent damage to the cochlea without any sharp pain to warn you. Extremely loud sound (e.g. 130 decibels) may stimulate pain fibres in your eardrum signalling an earache.
Protecting your hearing
Avoid loud noise. Loud bangs tend to be more damaging than continuous noise, particularly when they occur with no warning, which is mostly the case. Like sun exposure and skin damage, the amount of hearing damage is related to the intensity of the noise and the length of time you are exposed to it.
- Do not deliberately subject yourself to very high sound levels such as noisy machinery or loud rock concerts.
- For musicians, who are particularly at risk, special plugs are available.
- Wearing personal stereos, instead of ear muffs, increases the noise dose because listeners turn them up to blank out background noise and therefore increase the risk of damage.
- Be aware that your risk increases if you are occupationally exposed to solvents or toxins or if you are taking certain drugs.
- Talk to your occupational health and safety officer about making your workshop quieter. Remember, it is an employer's responsibility to provide a safe work environment.
- If you cannot avoid loud sound, then you should protect your ears with earplugs or ear muffs. Balls of cottonwool or paper tissue offer little protection.
- You should give your ears frequent rest from noise.
- When you attend discos, motor races or fireworks displays we recommend that you wear earplugs. Learn to fit them correctly, because poorly fitted earplugs offer little protection.