Types of hearing loss: Hearing loss is categorized by what part of the auditory system is damaged. These fall into three categories: Conductive hearing loss, sensorineural hearing loss, or mixed hearing loss.
Conductive Hearing Loss
Conductive hearing loss: This type of hearing loss occurs when sound cannot travel through the outer ear to the eardrum and tiny bones of the middle ear. This type of hearing loss can often be treated medically or surgically. Conductive hearing loss can be caused by:
- Fluid from colds or allergies (serous otitis media)
- Poor eustachian tube function
- Ear infection (otitis media)
- Perforated eardrum
- Benign tumors
- Impacted earwax (cerumen)
- Infection in the ear canal (external otitis)
- Presence of a foreign body
- Absence or malformation of the outer ear, ear canal, or middle ear
Sensorineural Hearing Loss
Sensorineural hearing loss occurs when there is damage to the inner ear (cochlea) or to the nerve pathways from the inner ear (retrocochlear) to the brain. Sensorineural hearing loss cannot be medically or surgically corrected. It is a permanent loss. Sensorineural hearing loss not only involves a reduction in sound level, or ability to hear faint sounds, but also affects speech understanding, or ability to hear clearly. This type of hearing loss is best treated with the use of hearing aids. Sensorineural hearing loss can be caused by:
- Birth injury
- Drugs that are toxic to the auditory system
- Genetic syndromes
- Noise exposure
- Head trauma
Noise induced hearing loss is one of the most common types of sensorineural hearing loss. Noise can be damaging to the sensitive cells of the inner ear. It can occur with a one-time exposure to a loud sound or over time to continuous exposure. Noise induced hearing loss can affect everyone, from infants to the elderly. To prevent noise induced hearing loss, you should be aware of the types of noise that are too loud. Noise greater than 85 dB may potentially cause damage to your ears. Some examples of these types of noise are gas lawn mowers, hair dryers, rock concerts, hand drills, ambulance sirens, and fireworks. Personal music players can also be made loud enough to potentially cause damage to your hearing.
Mixed Hearing Loss
Mixed hearing loss is a combination of a conductive hearing loss and sensorineural hearing loss. In other words, there may be damage in the outer or middle ear and in the inner ear (cochlea) or auditory nerve. When this occurs, the hearing loss is referred to as a mixed hearing loss.