Types of Hearing Loss
There are four commonly recognized different types of hearing loss:
Conductive Hearing Loss
A conductive hearing loss occurs when sound is not conducted efficiently through the ear canal, eardrum, or through the tiny bones of the middle ear. This results in a reduction of the loudness of a sound. Common causes of a conductive hearing loss include:
- Trauma to the ear
- Fluid in the middle ear
- Excessive wax in the outer ear canal
- Outer ear infection
Sensorineural Hearing Loss
Often referred to (in error) as “nerve deafness” a sensorineural hearing loss is caused by damage to the hair cells in the cochlea. These cells cannot be repaired or replaced. Common causes of sensorineural hearing loss include:
- Exposure to loud noises
- The aging process
- Viral Infections
- Trauma to the ear
- Medications that are toxic to the ear
Typically a sensorineural hearing loss is permanent and irreversible. The only solution for most people with a sensorineural hearing loss to improve their ability to hear is to use hearing aids.
Mixed Hearing Loss
Some people have both a conductive and a sensorineural hearing loss. A combination of the two different types is referred to as a mixed hearing loss. For example, a mixed loss can occur when someone has a sensorineural hearing loss and develops fluid in their middle ear causing a conductive hearing loss. They may notice a decline in their ability to hear as a result of the temporary change in their hearing caused by the conductive hearing loss. Once the conductive hearing loss is resolved, their hearing levels should return to the level it was prior to the conductive hearing loss.
Central Hearing Loss
Our outer and inner ears allow us to “hear” sound, but the brain, allows us to “understand” sound. Various medical issues can cause our processing of auditory stimuli to breakdown causing a central hearing loss also known as an auditory processing disorder. Persons with a central hearing loss can hear sound but have difficulty with understanding or processing what they heard. When a central hearing loss is suspected, there are tests that can be done to determine if a hearing loss is due to a central auditory processing problem.