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Types and causes of hearing loss

How do we hear?

To understand hearing loss, first we need to understand how sound works. A sound starts as a movement of air that creates soundwaves. When soundwaves are picked up by the outer part of our ear, the process of hearing begins. A mechanical process sends the soundwave to the inner ear, which sets up an electrical process that activates our brain to perceive it as sound.

In other words, our sense of hearing is a complex process in which both mechanical and electrical (nerve) systems work together. If one or more parts of those systems are interrupted, we may experience hearing loss.


Types and causes of hearing loss

The causes of hearing loss vary and the type of hearing loss is determined by the part of the ear in which the impairment occurs. There are generally three different types of hearing loss: conductive, sensorineural and mixed hearing loss.

Click the buttons below to learn more about each type: 

ear-anatomy ear-anatomy ear-anatomy ear-anatomy ear-anatomy

Conductive hearing loss

A conductive hearing loss is often temporary and can sometimes be corrected with wax removal, medication or surgery. Conductive loss stems from problems in the outer or middle ear and can be caused by:

  • Infection
  • Build-up of wax or fluid
  • Punctured eardrum
  • Otosclerosis – an abnormal bone development in the middle ear

Degrees of hearing loss

Measured in degrees, hearing loss is divided into levels that are based on a person's auditory thresholds, or the softest sounds (decibels), they can hear.

Hearing Degree of Loss Impact
Normal Hearing 0 to 25 dB Hearing is considered normal
Mild Hearing Loss 25 to 40 dB Difficulty understanding speech in noisy situations. Hearing enhancement devices may be required in certain situations.
Moderate Hearing Loss 40 to 60 dB Difficulty understanding speech in most situations where there is more than one talker, or when listener cannot see talker’s face. Hearing aids are required.
Severe Hearing Loss 60 to 80 dB Difficulty hearing and understanding loud speech. Hearing aids are required but may still have difficulty understanding in some situations when the listener cannot see the talker’s face.
Profound Hearing Loss 80 dB or more Difficulty hearing and understanding most situations even with hearing aids.


Temporary hearing loss

There are times where a hearing loss is temporary. A temporary hearing loss is common and can be caused by any of the following:

  • Excessive earwax
  • Ear infections
  • Allergies
  • Sinus problems
  • Certain medications

To find out if you or someone you love has a hearing loss, please contact your local Hearing Care Professional. 

Hearing Care Professional
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