SOUND, NOISE AND TINNITUS... TAKING CARE OF YOUR EARS

Sound is measured by its frequency and its intensity. Frequency is the pitch high or low. Intensity is the volume or loudness. Loudness is measured in decibels (dB), and the higher the decibels - the louder the sound. And the result is an increased risk of damage to hearing.

Sounds vary from pleasant to unpleasant. What may be pleasing to some people may be annoying to others. When sound becomes annoying it is described as noise. Noise can be annoying but not always damaging to our hearing. However there are sounds of such intensity that tinnitus or even permanent hearing loss can result. This of course varies from person to person. There are no hard and fast rules to susceptibility.

We are surrounded by noise and sound. We cannot avoid exposure to it, whether indoors or out, from clocks ticking, traffic, machinery, and of course music. In the main we try to keep ourselves in a comfortable hearing environment.

Understanding Sound

Sound waves travel through the air into the outer ear and travel down the ear canal. The waves vibrate on the eardrum, passing over three tiny bones (the ossicles) which amplify the sound waves into the inner ear (cochlea).

The cochlea is a small circular shell shaped organ, which is filled with fluid and lined with thousands of tiny hair like cells called cilia. The sound vibrations create movement in the fluid causing the cilia to move and sway. As this happens tiny valves at the base of the cilia open and close, releasing fluid/electrical impulses called neurone transmitters, which travel to the brain and translate into sound.

Cilia activity increases with an increase in sound. This can be likened to a field of corn and the effect of wind in a storm. In a gentle breeze or wind, the corn will not be affected very much. Even in a brief storm there may not be too much damage. However, with prolonged exposure the corn may be flattened and die. So it is with the cilia. When exposed to prolonged damaging noise, it will become worn and die. The damage is irreversible and cannot be repaired. In the case of tinnitus a distortion of sound may be apparent.

Although the cause of tinnitus is unknown, many people who have had long exposure to noise develop tinnitus. The hearing may also be affected at the same time, but not always. Noise induced tinnitus can happen gradually or very suddenly. Gradually with the cilia recovering a few hours after each exposure, the signs are usually ringing or buzzing in the ears, which may disappear after a few hours. However if the hearing is continually exposed to loud noise, the hearing mechanism will become more and more damaged.

There are no definite noise levels that are known to specifically induce tinnitus, but sounds below 85dB are considered safe. A guideline for noise exposure is, if you have normal hearing and you are exposed to some external noise, which makes it impossible for you to hear people talking to you who may be three or four feet away, the chances are that the noise around you is at a dangerous level.

SOUND ADVICE

1. Wear earplugs or ear protectors when you know that you may be exposed to loud noise at work or at leisure.
2. At parties or discos there is no need to stop enjoying yourself: just keep your distance from the speakers and if possible just lower the volume. After all it is the company that make the party!
3. Avoid noise wherever possible.
4. Reduce the time you are exposed to noise.

The following graph will help you to understand levels of sounds that you may encounter, thereby allowing you some control and understanding of sound and your precious hearing.



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