ABOUT HEARING LOSS
Hearing Loss impacts 1 in 6 people in our society.This section includes:
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Causes of Hearing Loss
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Noise Induced Hearing Loss
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Types of Hearing Loss
Causes of Hearing Loss
CAUSES OF HEARING LOSS
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Hearing loss conditions can be caused by a variety of medical conditions and disorders which can affect hearing and/or the ability to understanding speech.
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The most common causes of hearing loss are:
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• Congenital hearing loss (present at birth or soon after birth)
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• Jaundice or lack of oxygen at birth
• Genetic (inherited) disorder
• Middle-ear infections
• Illnesses such as Mumps, Rubella (German Measles), Meningitis or Meniere’s Disease.
• Ageing
• Major infections
• Exposure to loud noise
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• A head injury or trauma and
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• Exposure to certain chemicals and/or medications that damage the ears
Most hearing losses are sensorineural and therefore cannot be reversed.
Various rehabilitation options are available to help overcome some of the problems caused by hearing loss. A minority of hearing losses (mostly conductive) can be surgically improved.
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LISTENING DISORDERS
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• CENTRAL AUDITORY PROCESSING DISORDER
Central Auditory Processing Disorder is an umbrella term for a variety of disorders that result in a breakdown in hearing and listening processes.
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This is a complex problem affecting about 3% – 5% of school-aged children.
Something adversely affects the way the brain recognises and interprets sounds, most notably the sounds composing speech.
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Remediation options include auditory training programs, management strategies and assistive technologies for use in the classroom.
Noise Induced Hearing Loss
HOW DOES NOISE AFFECT HEARING?
Noise is any unwanted sound. It can interfere with communication and limit your ability to socialise and tune into friends. Sometimes noise can render vital safety signals inaudible causing accidents.
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Even quite modestly loud sounds can prevent us from just enjoying the natural environment.
Sound which is too loud for too long will eventually affect your hearing.
Loud sound can also cause ringing in the ears, affect balance and may increasingly isolate people from their friends and family.
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HOW MUCH NOISE IS TOO MUCH?
This depends on the loudness of the sound, how long you are exposed and to some extent how impulsive the sound is. Sound starts becoming hazardous around 80 decibels.
You can do a rough sound level check with a “sound level meter app” which can be downloaded onto your mobile phone or tablet.
The following decibel chart provides approximate sound levels of some common sounds.
The decibel chart shows many sounds commonly experienced in the home, at work or in recreational activities which can be hazardous.
How hazardous depends on how long you are exposed. 85 decibels for eight hours is the current exposure standard in Australia. This is the same exposure as 88 decibels for four hours or 91 decibels for two hours.
However sounds above 140 decibels are dangerous for any exposure.
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MAIN CAUSES OF HAZARDOUS NOISE
Noise induced hearing loss can result from noise exposure at home, at work and at play.
However most noise induced hearing loss, by far, is caused at work.
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NOISE IN THE WORKPLACE
Construction, Transport, Mining, Agriculture and Defence are industries where noise induced hearing loss is common. Those who work in Entertainment (musicians, hospitality and other workers) can also be exposed to high levels of noise.
Occupational health and safety legislation in Australia regulates noise in industry.
Action to control noise and protect hearing must be taken by employers when noise levels exceed 85 decibels averaged over a working day and for noise levels above 140 decibels for any time.
This must be measured at the worker’s ear, without hearing protection devices.
When hazardous noise levels cannot be reduced to safe levels then a hearing protection program must be provided to employees working in noise.
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Some simple tips include:
1. Talk with your supervisor and health and safety representative about noise assessment, cutting down noise levels and audiometric screening
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2. Always wear hearing protection when needed.
Further information on noise and hearing conservation at work can be found at WorkSafe Victoria: www.worksafevic.goc.au
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NOISE IN THE HOME
Many appliances produce hazardous noise levels – such as:
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Garden tools – for example – chainsaws, mowers, blowers, and shredders
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Workshop tools – for example – grinders, power saws and hammers; and
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Indoor Appliances such as vacuum cleaners; and
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Activities at Home – for example – home renovations
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Consumer and environmental laws in Victoria offer some protection to consumers but ultimately the main safety messages come down to what you can do in the home.
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Some simple tips include:
1. Buy quiet. Check the noise level ratings on noisy products before you buy.
2. Find the quietest way. Screws and glues are quieter than nails. Why blow leaves away at all and sweeping is a good approach.
3. Wear hearing protection always for noisy activities.
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RECREATIONAL NOISE
Guns, vehicles and music are among the main sources of leisure activities dangerous for hearing. High calibre firearms can produce up to 170 decibels and, at that level, ear muffs only offer partial protection. Motor bikes, and modified cars can cause hearing damage.
Venue music, personal listening devices, car radios can be hazardous.
Some simple tips include:
1. Control the activity music venues are required to keep music levels safe. Maintain vehicle engines and exhausts. Avoid firearm exposure.
2. Set personal listening devices to safe levels.
3. Always wear hearing protection when exposed to noisy activity.
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ARE YOU AT RISK?
If you want to check how hazardous your exposure to noise is or you want to see how well you hear in background noise, visit HEARSmart/National Acoustic Laboratories
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Know Your Noise website: www.knowyournoise.nal.gov.au
Types of Hearing Loss
There are four types of hearing loss:
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• Conductive hearing loss
• Sensorineural hearing loss
• Mixed hearing loss and
• Auditory Neuropathy
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CONDUCTIVE HEARING LOSS
Conductive hearing loss can occur when there is damage or a blockage in the outer and/or middle ear.
This can result in sound not being conducted adequately through the ear canal to the eardrum, or from the eardrum via the ossicles of the middle ear to the inner ear.
It can be caused by earwax, a perforated eardrum, a build up of fluid in the middle ear from a cold or flu, (often referred to as ‘glue ear’), abnormal bone growth involving the ossicles, repeated ear infections and allergies.
It is more common in children and indigenous populations.
Medical interventions and technologies are often used to treat conductive hearing loss.
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SENSORINEURAL HEARING LOSS
Sensorineural hearing loss occurs when there is damage or malfunction of the hair cells in the cochlear.
Sensorineural hearing loss is the most common type of permanent hearing loss.
Assistive technologies can help reduce the effects of sensorineural hearing loss.
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MIXED HEARING LOSS
A mixed hearing loss occurs when both conductive and sensorineural hearing losses are present.
The sensorineural component of the hearing loss is permanent, while the conductive component may be permanent or temporary.
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AUDITORY NEUROPATHY
Auditory Neuropathy occurs when there is a problem with the auditory nerve transmitting the signal from the cochlea to the brain.
The hearing loss can vary from normal to profound and hearing levels may fluctuate.
Understanding speech in background noise can be a particular difficulty.
The cause of auditory neuropathy includes lack of oxygen or jaundice at birth, or some neurological conditions. Assistive technologies can usually help reduce the effects of auditory neuropathy.