Types of Hearing Loss
There are four categories of hearing loss.
Central, conductive, sensorineural, and mixed.
Central Hearing Loss
This least common form of hearing impairment occurs as a result of a problem in the central auditory system. Although the outer, middle and inner ear parts deliver sound signals, they are not processed by the brain. Sound amplification does not address this type of dysfunction.
Conductive Hearing Loss
Conductive hearing loss results from malfunction of the outer and/or middle ear. Causes can be as simple as impacted earwax, or as serious as middle ear infection, eardrum perforation or dislocation of the middle ear bones.
Most of these symptoms can be medically or surgically treated. When treated in time, some conductive hearing losses may not require artificial amplification. Untreatable cases often result in the need for a hearing aid or other hearing assistive devices.
Sensorineural Hearing Loss
By far the most common type of hearing impairment, Sensorineural loss is usually the result of cochlear haircell damage. Sound may be conducted normally to the inner ear, but the damaged haircells are unable to ‘trigger’ and therefore cannot send signals to the central auditory system. In most cases those that do ‘trigger’ are damaged and as a result send a distorted message to the brain.
Because the cochlea is tiny and the haircells are microscopic, no medical procedure and ‘reverse’ sensorineural hearing loss. The loss can be aided with amplification, essentially allowing remaining haircells to respond to the best of their abilities.
Common causes of sensorineural hearing loss are:
- Prolonged exposure to excessive noise
- Hereditary predisposition
- Ototoxic medication
- Prenatal, perinatal or congenital factors
Hearing and Age
Age is the most prevalent cause of hearing loss and impairment. Age induced hearing loss, known as Presbycusis, occurs as part of the body’s natural wear and tear over time.
Mixed Hearing Loss
A condition in which both the conductive and sensorineural hearing loss is present. Both the middle and inner ear are affected.