Hearing Loss – Causes, Types & Degrees

One in six Australians is affected by hearing loss. Most hearing losses occur gradually so the signs are often difficult to recognise. Some people may not want to admit they are having trouble hearing. People with a hearing loss often report that “they can hear the conversation, but can’t understand what is being said”.

What you need to know about hearing loss


The main causes of hearing loss are:
– The ageing process
– Excessive exposure to loud noise

Age-induced hearing loss: The most common cause of hearing loss is often referred to as age-induced hearing loss or Presbycusis. The ‘wear and tear’ on our ears over time damages the inner ear. This causes gradual progressive and permanent hearing loss

Noise-induced hearing loss: Exposure to loud noises may also cause damage to the cochlea in the inner ear, resulting in a permanent sensorineural hearing loss. Noise-induced hearing loss may be as a result of prolonged exposure to loud sounds or may be caused by one incident of exposure to loud noise. Hearing protection is strongly recommended for anyone who is exposed to loud noises such as industrial or construction workers, fire-arm users and musicians. It is also important to limit the use and volume of personal music players.

Hearing loss can also be caused by :

  • Genetic / Hereditary conditions
  • Diseases / Syndromes
  • Medications / Ototoxic
  • Drugs
  • Head Injuries
  • Infections


There are three types of hearing loss: conductive, sensorineural and mixed and each type affects a different part of the ear. It is important to visit an audiologist to diagnose your type and degree of hearing loss.

Sensorineural hearing loss (SNHL) – indicates there is damage to inner ear hair cells or in the hearing nerve pathway and sound cannot reach the brain where it is processed. SNHL is permanent. Hearing aids and a comprehensive rehabilitation plan are usually recommended as treatment.

Conductive hearing loss (CHL) – occurs when the sound waves are blocked in the outer or middle ear and cannot pass through to the inner ear. Causes of CHL include middle ear infection, a build-up of ear wax or fluid due to colds. Conditions may be temporary and/or improved with medical treatment.

Mixed Hearing Loss – Mixed hearing loss is a combination of both conductive and sensorineural hearing losses. Conductive loss can be treated with medicine or surgery; sensorineural hearing loss is permanent but can benefit from hearing aids.


Hearing loss is usually described in terms of degree of loss.

The degree of hearing loss is defined in ranges of mild, moderate, moderately severe, severe and profound.

Hearing loss is measured on an audiogram. The audiogram reflects your hearing thresholds ( the softest sound that someone can hear). These thresholds are tested across a range of frequencies, from low pitched through to high pitched sounds. The audiogram provides a summary of your hearing loss – type, pattern and degree of hearing loss and can be compared to the ‘normal’ hearing range.

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