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 can be completely 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 sensorineural 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 is 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.