In general terms, there are two types of hearing loss, conductive and sensorineural. Whether a hearing impairment is categorized as a conductive or sensorineural hearing loss depends on the origin of the hearing loss.
Conductive Hearing Loss
Conductive hearing loss is caused by any condition or disease that blocks or impedes the conveyance of sound through the outer or middle ear. The result is a reduction in the sound intensity (loudness) that reaches the inner ear. Generally, the cause of conductive hearing loss can be treated with a complete or partial improvement in hearing.
There are a number of conditions that may cause conductive hearing loss:
- Outer or middle ear infection
- Fractured middle ear bones
- Fixated middle ear bones
- Perforated eardrum
- Outer ear deformity
- Earwax
Sensorineural Hearing Loss
Sensorineural hearing loss results from inner ear or auditory nerve dysfunction. Often, the cause cannot be determined. It is typically irreversible and permanent. It, too, reduces the intensity of sound, but it might also result in a lack of clarity even when sounds, particularly speech, are loud enough. The treatment for sensorineural hearing loss is amplification through hearing aids.
There are a number of conditions that may cause sensorineural hearing loss:
- Damage to the sensory cells or nerve fibers of the inner ear (aging or acoustic trauma)
- Exposure to diseases like mumps, meningitis, multiple sclerosis, or Meniere's disease
- Use of certain drugs such as aspirin, cisplatin, quinine, streptomycin, and gentamicin
- Low birth weight
- Genetics
- Head or ear injuries
Mixed Hearing Loss
A mixed hearing loss is a combination of a conductive and a sensorineural hearing loss. Hearing aids can be beneficial for people with a mixed hearing loss.