Types of Hearing Loss
Conductive Hearing Loss
This type of hearing loss is caused by problems in the ear canal and/or the structures in the middle ear. It occurs when sounds from the outside world cannot be transmitted normally through the ear canal and/or middle ear to the inner ear. The most common causes of conductive hearing loss can be a build-up of wax in the ear canal, a perforated eardrum, fluid in the middle ear (fluid behind the eardrum), or damaged/defective ossicles (middle ear bones). A person with conductive hearing loss may notice their ears seem to be full or feel “plugged”. Most conductive hearing losses can be medically or surgically treated. If for some reason the hearing loss cannot be corrected, hearing aids can provide benefit.
Sensorineural Hearing Loss
This type of hearing loss is the most common type of hearing loss. More than 90% of all hearing aid wearers have sensorineural hearing loss, resulting from problems in the inner ear or the auditory nerve. Inner ear hair cell damage is the most common reason for sensorineural hearing loss. These tiny hair cells, once damaged or destroyed, become unable to convert sound vibrations into the electrical signals needed by the hearing nerve.
Sensorineural hearing loss can also be attributed to long-term occupational or recreational exposure to loud noise. It also commonly occurs in the later decades of life (typically many years after the period of exposure).
People with sensorineural hearing loss typically report that they can hear people speak, but they can’t understand (or clearly hear) what has been said. It often seems to them that people are “mumbling”. Usually there is no medical way to correct this, but hearing aids are an excellent option.
Mixed Hearing Loss
This kind of hearing loss is caused by a combination of problems in the middle and the inner ear/hearing nerve (ie. part mechanical, part nerve-level). For example, the person may have a noise-induced hearing loss from noise exposure, as well as a perforation (hole) in the eardrum. The combination of sensorineural and conductive hearing loss is therefore considered mixed.