Hearing loss can be categorized by the part of the auditory system that is affected or by the location within the auditory system. There are three main types of hearing loss: conductive, sensorineural, and mixed hearing loss.
Conductive Hearing Loss
Conductive hearing loss happens when sound is not efficiently conducted through the outer ear canal to the eardrum and the small bones of the middle ear. This type of hearing loss usually involves a reduction in the ability to hear faint sounds. Conductive hearing loss can often be helped and or corrected either medically or surgically.
Conductive hearing loss may be caused by the following conditions:
- Fluid in the middle ear from colds
- Poor function of the eustachian tube
- Ear infection (otitis media)
- Benign tumors
- Infection in the ear canal (external otitis)
- Perforated eardrum
- Impacted earwax (cerumen)
- 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 damage occurs to the cochlea, or inner ear, 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. This type of hearing loss not only involves a reduction in the ability to hear faint sounds but also affects the ability to hear clearly.
Sensorineural hearing loss can be caused by the following:
- Certain drugs
- Birth injury
- Genetic syndromes
- Exposure to noise
- Head trauma
- Aging Process
Mixed Hearing Loss
A mixed hearing loss is described as a combination of conductive hearing loss with sensorineural hearing loss. Damage in the outer or middle ear occurs along with damage in the inner ear or auditory nerve.