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types and causes of hearing loss

Types and Causes of Hearing Loss

It is important to note that not all hearing loss is the same. Hearing loss is categorized into four main types, according to the part of the hearing pathway that is affected:
  1. Conductive
  2. Sensorineural
  3. Mixed
  4. Central hearing loss
1. Conductive Hearing Loss

Conductive hearing loss occurs when audible sound waves are unable to reach the inner ear. Conductive hearing loss is caused by problems with the outer or middle ear.

Common causes of conductive hearing loss:

If hearing loss is purely conductive, it is often possible to improve hearing with medical or surgical treatment. In some cases, conductive hearing loss is permanent. However, in these cases, individuals will often benefit from hearing aids.

2. Sensorineural Hearing Loss

Sensorineural hearing loss is most common, accounting for 90% of all hearing loss. Sensorineural hearing loss occurs when sound waves reach the inner ear; however, the cochlear “hair cells” or hearing nerve are not working properly.

Common causes of sensorineural hearing loss:

Unlike conductive hearing loss, sensorineural hearing loss is usually permanent and cannot be treated medically or surgically. Once hair cells in the cochlea have been damaged, there is no way to replace or repair them. However, many people with sensorineural hearing loss can benefit from hearing aids.

3. Mixed Hearing Loss

Mixed hearing loss is a combination of conductive and sensorineural hearing loss.  Sound waves are less efficiently transferred to the inner ear and, if they do reach the inner ear, the cochlear hair cells or hearing nerve do not receive them properly.

Common causes of mixed hearing loss: 4. Central Hearing Loss

As sound waves reach the auditory nerve, the auditory nerve may not send electrical signals to the brain, or the brain may not interpret these signals properly. This is referred to as central hearing loss.  People with central hearing loss are often able to detect sound but may not be able to interpret or understand them.

Common causes of central hearing loss are:

Central hearing loss can be diagnosed through specialized tests that assess a person’s ability to interpret complex auditory information.