Hearing Loss Prevention (Protection)

 

Hearing loss can result from a number of different causes, many of which are preventable. In order to prevent hearing loss, people need to be aware of things that can damage their hearing, and learn ways of ensuring their hearing health. For example, exposure to excessively loud noise will cause hearing loss. People must learn to look after their hearing by minimising their exposure to loud sounds and noise or avoiding noisy situations altogether.

It has been determined that exposure to noise is the most common cause of preventable hearing loss experience in the community. When preventable hearing loss is further coupled to loss due to the ageing process (presbycusis) it is easily understood why hearing loss is more common in the older age groups.

For individuals not experienced with hearing loss it can be very difficult to understand the frustration and difficulties that arise from such an every-day process that we take for granted. Adjusting to living with a hearing loss can be a slow and difficult process. This is why hearing loss prevention is an important aspect of NAL's research programme.

Noise Exposure

Noise is one of the most common causes of hearing damage (noise injury). The risk of permanent hearing loss from noise is related to the loudness of the noise and the duration of the exposure.

A noise injury is mostly acquired gradually as the result of exposure to loud noises over an extended period of time. Typically this has been through working in a noisy environment, however, of more recent concern is the trend toward numerous noisy leisure activities that are also capable of causing damage to hearing. The hearing mechanism does not distinguish between noise and music. This is a function of higher processes in the brain.

One-off exposures to extremely high levels of impulse sound (e.g. sound of a gun shot) can and do cause instantaneous damage to hearing.

Repeated or prolonged exposure to loud sounds increases the risk of hearing damage, and the effects are cumulative. The loudness of a sound is measured in decibels which is a non-linear scale used for scientific purposes. For the purposes of looking after your hearing the most important thing to note is that if you need to use a raised voice to communicate or carry on a normal conversation between two people at arms length then the noise level is potentially hazardous and exposure over a significant time could bring problems. This sound level is usually in the range of 85 to 90 dB A-weighted. If, after experiencing loud noise, for example after a dance party or ‘loud’ event the world appears a little quieter and/or you have ringing in your ears then the sound level is definitely hazardous. Your ears are giving you a warning to be careful.

Sounds below 75 decibels are unlikely to cause hearing damage, regardless of the duration of exposure. As the loudness of the sound increases, the duration of “safe” exposure decreases. For example, exposure to sounds above 85 decibels for more than 8 hours a day significantly increases the risk of subsequent hearing loss.

The damage is caused by too much noise reaching your ears. This noise exposure is a function of loudness and time so if you wish to reduce your exposure you must firstly reduce the volume or loudness and then the time. Noise exposure is cumulative over your life-time, meaning that every over exposure adds up – just like too much UV-radiation or exposure to the sun. In the short term there seem to be no serious effects but it is the long term that counts.

Hearing slowly gets damaged in an almost imperceptible way and it can take many years of exposure for the effected individual to actually take notice. Noise injury is painless and bloodless and does not rate high on a scale of physical injury such as a broken arm or leg but have no doubt it is a real injury nevertheless.

Thus it is important to take a long term perspective and reduce your noise exposure. You can improve your hearing health by making sure you,

Remember "If you lose it, it won't come back".

Workplace Noise

The loss of hearing through exposure to excessive noise in the workplace is a well documented occupational health and safety (OHS) issue. Many workplaces have the potential for a degree of noise exposure, however, some workplaces are identified as posing a particularly high risk for hearing. All workplaces are obliged by legislation to have an appropriate noise assessment.

Some examples of noisy workplaces include:

Manufacturing
Construction
Mining
Hospitality and entertainment.
Transport.

The main point is that you do not need to be any sort of a noise expert to know if something is noisy. If the noise level is such that you need to raise your voice to carry on a normal conversation then chances are that it is too noisy. This is particularly important if your work requires that you are exposed to this level of noise for significant periods throughout your normal work routine. If in doubt ask your supervisor, manager or workplace colleagues. Remember everybody has some responsibility for workplace health and safety. It cannot be delegated or simply shrugged off.

Steps have been taken through OHS legislation and regulations to limit the amount of noise to which workers are exposed in order to minimise the health risks. OHS regulations exist with respect to continuous noise and any loud peaks. These regulations set mandated acceptable levels, and the nature of employers' and employees' responsibilities for reducing any exposure above these limits.

Noise exposure can be reduced via a variety of different "control" methods. As with other hazards, these different methods exist within a "hierarchy of controls" outlined below:

1. Eliminate the hazard by eliminating the source of the noise;
2. Minimise the risk through engineering noise controls or substitution of noisy equipment;
3. Implement administrative controls by removing staff from noisy areas or arranging to produce noise at times when there is minimum effected staff;
4. Provide Personal Protective Equipment (PPE) such as supplying ear plugs, ear muffs accompanied by an effective education and training programme.

But note that the use of PPE is acceptable only as an interim measure until noise levels can be reduced or if there is no alternate practicable solution. PPE is not seen as a long term solution. For this reason controls at the top of the hierarchy are preferable as they remove the hazard and do not rely on changing workplace behaviour for safe working conditions. It has been shown that reliance on PPE is not an effective long term solution. Although the lower level controls have the potential to be effective, they are less reliable, relying on individual workers to take steps to protect themselves.

Leisure Noise

High levels of noise exposure have traditionally been discussed in terms of workplace noise exposure, with the hearing loss often being referred to as 'industrial' or 'occupational' deafness. However, non-workplace or leisure noise can be just as damaging if the levels or duration reach risk levels.

High levels of leisure noise can come from more traditional activities such as motor bike riding, shooting, use of power tools, etc, or from more contemporary sources such as pub bands, concerts and personal stereo players. Just as with workplace noise, if you have trouble conversing over the noise level then it is potentially too loud and exposure must be reduced.

In principle the same preventative action should be adopted even though this may at first seem more difficult when operating in a different social situation when compared to the workplace. Sometimes it can be awkward to reduce the volume or get further away from the noise/sound source without appearing antisocial or ill-mannered. But you need to look after your hearing so some action must be taken: remove the noise, reduce the volume or remove yourself.

If you experience tinnitus or ringing in your ears after a particular heavy concert then be warned, your ears are trying to tell you something. Be sure to heed the message.