There are several different varieties of hearing loss, depending on which section of the auditory is affected. In this brief article we offer an introduction to five categories – conductive, sensorineural, central, mixed and functional. The first step in creating a therapy plan is to properly identify the type of hearing impairment.
Sensorineural hearing loss – This type of hearing loss is responsible for more than 90% of the instances in which a hearing aid is worn. It is due to damage in the interior of the ear or damage to the acoustic nerve, which prevents sound signals from being transmitted to the brain. Also known as retrocochlear hearing loss or nerve deafness, the damage is for the most part irreversible, although advances in technology have permitted some formerly untreatable cases to see some improvement.
The most common factors that cause sensorineural hearing loss are the aging process, prolonged exposure to noise, issues with blood circulation to the inner ear, fluid disturbance in the inner ear, drugs that cause injury to the ear, a small number of diseases, heredity and problems with the auditory nerve.
Hearing aids are suitable for most people that have this type of hearing loss, but in more severe cases, a cochlear implant can help restore hearing to those for whom a conventional hearing aid is insufficient.
Conductive hearing loss – In situations where sound waves aren’t completely conducted to the interior of the ear through the outer and middle ear, conductive hearing loss occurs. This is rather common and can be due to a buildup of ear wax, an accumulation of fluid in the eustacian tube, which prevents the eardrum from moving, a middle ear infection, a perforated eardrum, disease of the bones of the middle ear or obstructions in the ear canal.
The majority of instances of conductive hearing loss are reversible, presuming there isn’t any permanent damage to the structures of the middle ear, and with treatment the trouble usually resolves in a short amount of time. For some patients surgery can assist in correcting the condition or a hearing aid may be recommended.
Functional hearing loss – A rare occurrence, functional hearing loss is not physical. This condition is caused by psychological or emotional condition in which the person’s physical hearing is normal, but they do not seem to be able to hear.Mixed hearing loss – As suggested by the term, mixed hearing loss is a blend of multiple types of hearing loss, in this case the combination of sensorineural and conductive hearing loss. Although there are a couple of other kinds of hearing loss, the combination of these two is most common.
Central hearing loss – This condition occurs in situations where an issue in the CNS (central nervous system) blocks sound signals from being processed by the brain. Affected individuals can ostensibly hear perfectly well, but cannot decode or decipher what is being said. Numerous cases involve a problem with the individual’s ability to properly filter competing sounds. For example, the majority of us can hold a conversation while there is traffic noise in the background, but people with central hearing loss have a really hard time with this.