Approximately 1 in 6 Australians experiencing some form of hearing loss.1
Hearing impairment is caused by many different factors, the most common cause of hearing loss often develops with age or exposure to excessively loud noise. Hearing loss progresses over time and it is best to recognise the signs early.
Quality of life can be significantly compromised for people with hearing loss and their families. The extent of the hearing loss varies too, from a mild to a severe hearing loss where loud safety signals may not be heard. More commonly it is manifested as a difficulty with word understanding, particularly in the presence of background noise.
Signs of hearing loss
In contradiction to many people’s understanding, hearing loss is rarely similar to the effect of turning down the volume on a stereo. It usually affects different frequencies of sound by varying amounts. This can lead to conversations being difficult to follow, particularly in noisy environments where competing background noise’ scrambles speech and conversations are the single biggest reason that people seek our help.
If you feel that your hearing is not what it used to be, or are concerned that a loved one may be experiencing hearing loss, take a couple of minutes to do our online hearing test to evaluate your hearing health.
Types of hearing loss
There are three forms of hearing loss, Conductive, Sensorineural and Mixed Hearing Loss.
Conductive Hearing Loss
Conductive hearing loss results from a problem with the passage of sound through the outer ear and/or middle ear. Some common examples include:
- Excessive cerumen (earwax) in the ear canal
- Perforation of the eardrum
- Middle ear infection with fluid build-up
However, conductive loss accounts for only 10% of all hearing losses, and they range from mild to moderate in severity. The good news is that conductive hearing loss can often be medically treated, and in many cases, hearing could be restored.
Symptoms of Conductive Hearing Loss
With conductive hearing loss, the overall volume of sound is reduced. Signs of conductive hearing loss may include:
- Turning up the volume on the television or radio
- Asking people to repeat what they say
- Hearing in one ear better than the other
When volume is sufficiently increased, clarity and understanding are usually intact for someone with a conductive hearing loss. Other symptoms may also be present, such as ear pain, drainage from the ears, or a feeling of pressure or a blockage.
Sensorineural Hearing Loss
Hearing loss that originates in the inner ear is referred to as sensorineural hearing loss or in laymen’s terms, nerve deafness. The vast majority of hearing losses are sensioneural losses, and common causes include:
- Genetic factors (i.e. hearing loss can run in families)
- Excessive noise exposure either sudden or prolonged
- Changes in the inner ear due to ageing
Less common causes include:
- Reactions to ear-toxic medications
- Auditory nerve tumours
- Conditions acquired prior to birth (congenital)
- Infections such as meningitis and mumps
- Kidney disease
- Vascular disease
Each cause can lead to damage to the sensory hair cells or nerves. Once damaged, the hair cells can’t repair themselves nor be medically treated. Therefore, 90% of hearing losses cannot be cured.
A sensorineural hearing loss can be of any degree, mild, moderate, severe or profound. In more than 95% of cases involving sensorineural hearing loss, hearing aids or cochlear implants are the recommended course of treatment.
Symptoms of Sensorineural Hearing Loss
While the overall volume of sound may be reduced, the clarity of sounds or voices are also affected. People with sensorineural hearing loss will often hear people speaking, but can’t always understand all the words, even when the volume is adequate. Music may also sound distorted, leading to decreased enjoyment.
The symptoms of sensorineural hearing loss may include:
- Turning up the volume on the television or radio
- Asking people to repeat what they have said
- Perception of people mumbling or not speaking clearly
- Lack of clarity when listening to speech
- Difficulty hearing in noise.
Mixed Hearing Loss
The transmission of sound can be blocked in multiple places along the auditory path. When a hearing loss occurs from conditions in the inner ear as well as the outer and/or middle ear, this is known as mixed hearing loss.
An example of a mixed hearing loss may be someone with inner ear damage due to exposure to noise in their workplace over many years, who also currently has an infection that has led to a fluid build up in the middle ear.
Causes of hearing loss
While the ageing process is a major contributor to hearing loss, it is certainly not a condition reserved for the later stages of life. Studies have shown that exposure to noise is thought to be a contributing factor in around 37% of cases of the condition – and interestingly, around 50% of Australians with hearing loss are still of traditional working age (i.e. under 65 years).
Other contributing factors of hearing loss include:
- Infection or injury (17.1% of cases)
- Born with hearing loss (4.4% of cases)
- Other causes (16.8% of cases)
Noise induced hearing loss
Not surprisingly, given the impact of noise, males are considerably more likely to have hearing loss than women, including being twice as likely to have a moderate to severe hearing loss.
These days, people are more aware of the damage that noise can do to their hearing. This is illustrated through mandatory provision of ear protection on work sites and within factories. Nevertheless, every day millions of Australians are exposing themselves to noise levels that will surely lead to long-term damage to their hearing, including the use of personal stereo systems.
Nerves have different sensitivities to deformation of the sensory hair cells within the cochlea. A sound that has high frequencies of vibration will excite receptor cells near the opening of the cochlea, while a sound mostly containing low frequencies will stimulate cells at the end of the cochlea.
Commonly, over time the high frequency hair cell receptors receive more movement by the incoming pressure waves of the fluid inside the cochlea so are more prone to long term damage than the low frequency hair cell receptors, which are more protected further up the cochlea.
1Australian Network on Disability. Types of Disability [Online]