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Types and causes of hearing loss

Hearing loss has several different causes and contributing factors - some of which we can avoid, and others we can't. This page explains some of the most common types and causes of hearing loss.

Loss of hearing can be gradual or sudden. Gradual hearing loss can be difficult to detect, but the first signs usually include difficulty following conversations amid background noise, trouble understanding higher-pitched voices (such as children's) and needing to turn up the volume on the TV.

Sounds can be become harmful when they are too loud, even for a short amount of time or when they are loud and long-lasting at the same time. These sounds can damage sensitive structures in the inner ear which could cause noise-induced hearing loss.

High frequency hearing loss is the most widespread form of hearing deterioration as it is the result of the most common causes of hearing loss such as excessive noise exposure or ageing; both ears are usually affected to a similar degree. 

The two main types of hearing loss are sensorineural, which relates to the nerves in the inner ear, or conductive, which relates to problems with the ear canal, drum or middle ear. It can also be caused by a combination of the two (mixed hearing loss).

Our expert hearing aid audiologists are trained to identify the possible causes and refer you to an appropriate medical specialist, usually your doctor, if the cause of your hearing loss can be treated by medicine or surgery regardless of whether you have hearing loss in one ear or both ears.

Conductive hearing loss

Conductive hearing loss occurs when sound cannot reach the inner ear. Causes include:

  • A build-up of earwax
  • A build-up of fluid in the middle ear
  • Middle ear infection
  • Perforated eardrum
  • A foreign body
  • Abnormal bone growth in the middle ear (otosclerosis)

Blockages

A build-up of wax or fluid in the ear can cause hearing loss. The blockage can be a symptom of an ear infection, or it may just be an accumulation of hard ear wax. Ear drops can be used to soften and loosen ear wax, and if this doesn't work your GP can use a pressurised flow of water.

Perforated eardrum

This can be caused by infection in the middle ear, a severe blow to the ear or damage caused by a foreign body (such as a cotton swab in the ear). It often causes earache or discomfort, and loss of hearing. The eardrum often heals by itself within a couple of months, but if pain persists for more than two days you should see your GP.

Otosclerosis

This condition is an abnormal bone growth in the middle ear, which can interfere with the transmission of sound leading to gradual hearing loss. It typically develops in your 20s or 30s and can be treated with surgery, or with hearing aids.

These conditions may affect one or both ears and can often be cured by medicine or surgery. However, a person with conductive hearing loss may also benefit from using hearing aids. 

Sensorineural hearing loss

This is the most common form of hearing loss and occurs when the minute hair cells in the inner ear are damaged. It can be caused by a wide range of conditions but most commonly by the ageing process which accounts for around 90% of this type of hearing loss.

Sensorineural hearing loss is a natural part of ageing, but other factors may include:

  • Traumatic exposure to noise
  • Head injury
  • Viral infections of the inner ear and auditory nerve
  • Some drug treatments
  • Family history

Age

Age-related hearing loss is the single most common cause for partial loss of hearing. Also known as presbyacusis, it typically begins in your 40s and 50s and gets steadily worse as you get older: by the age of 80, the vast majority of people have some form of hearing loss.

Presbyacusis happens because the sensitive hair cells in the inner ear gradually become damaged or die as you get older, and do not regenerate. There is currently no cure for this, although there is promising research indicating that doctors may be able to regenerate hair cells sometime in the future.

Most people with age-related hearing loss wear hearing aids, which mimic the function of hair cells by detecting and amplifying low-level sounds.

Noise

Repeated exposure to loud noises will effectively speed up the process of age-related hearing loss, as the hair cells will become damaged earlier in life. You are particularly at risk if you work in a noisy environment, such as a nightclub, construction site or factory. Employers are required to provide hearing protection if the noise in their workplace exceeds 85 decibels.

Regularly listening to music at a high volume, especially with headphones, can also damage your hearing.Very loud noises such as explosions can also damage hearing temporarily or permanently, which is known as acoustic trauma.

Genetics

Genetic conditions can cause deafness from birth, or cause hearing loss over time. There is not always a family history present in these cases. Genetic hearing loss is usually not treatable, although it may be remedied with a hearing aid.

The condition is permanent and usually affects both ears but using correctly prescribed hearing aids can offer major benefits. 

Mixed hearing loss

Mixed hearing loss is a combination of conductive and sensorineural hearing loss and affects the outer, middle and inner ears.

High Frequency hearing Loss

High frequency hearing loss usually means that there is reduced hearing sensitivity predominantly at frequencies above 2000 Hz. 

A higher frequency hearing loss results in difficulty in understanding speech especially in the presence of background noise and will usually worsen over time.  There is a wide variety of hearing aid technologies to assist high frequency hearing loss as this type of hearing loss cannot normally be improved by medical treatment.