ACC ~ The Audiology Awareness Campaign
Hearing loss can develop at any age and may be caused by many different factors. Most hearing losses can be categorized as either sensorineural, conductive, or a combination of both sensorineural and conductive (mixed). It is important to understand the basic anatomy of the ear and hearing mechanisms before reading about the actual types of hearing loss.
Sensorineural Hearing Loss
Sensorineural hearing losses occur when the "inner" ear or the actual hearing nerve itself becomes damaged. About 90% of all people with hearing impairment are in this category, making it the most common type of hearing impairment.
Sensorineural hearing loss is often referred to as "nerve deafness." Nerve deafness is not really an accurate description because the damage most frequently occurs within the inner ear rather than the hearing nerve. Common causes of sensorineural hearing loss are aging and exposure to loud noises, but there are many other causes (viral infections, disrupted blood supply to the ear, metabolic disturbances, accident/injury, genetic predisposition, medications that are toxic to the ear, etc). Thus, "sensorineural" indicates the part of the ear that is malfunctioning and encompasses many different causes for the malfunction. This type of hearing loss is frequently not medically or surgically treatable. It is typically permanent and irreversible. However, most people with sensorineural loss find wearing hearing aids to be of significant benefit and some people with severe loss can benefit from a cochlear implant.
Conductive Hearing Loss
Conductive hearing losses occur when the "outer" or "middle" portions of the ear fail to work properly. Sound is "blocked" from being transferred to the inner ear at normal intensity. Conductive losses are often treatable with either medicine or surgery. Common causes of conductive hearing loss are fluid build up in the middle ear or wax blockage in the ear canal. Children are more likely to have a conductive hearing loss than a sensorineural hearing loss.
Mixed Hearing Loss
Mixed hearing losses are simply combinations of the above two types of hearing loss. They can occur when a person has a permanent sensorineural hearing loss and then also develops a temporary conductive hearing loss.