There are several different forms of hearing loss, based on which part of the auditory pathway is impaired. In this brief article we provide an overview of five types – sensorineural, conductive, functional, mixed and central. Some types of hearing loss are more treatable than other types, and a trained hearing care professional will be able to show you your options following an assessment.
- Conductive hearing loss – In situations where sound waves aren’t sufficiently conducted to the inner ear through the outer and middle ear, conductive hearing loss arises. This is rather widespread and can be caused by 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 blockages in the ear canal.Most cases of conductive hearing loss are reversible, assuming there is no irreversible damage to the parts of the middle ear, and with proper treatment the problem usually resolves fairly quickly. In some instances a surgical procedure can help to correct the issue or a hearing aid may be fitted.
- Sensorineural hearing loss – Sensorineural hearing loss is responsible for over 90% of the cases in which a hearing aid is used. Sensorineural hearing loss is due to damage in the interior of the ear or to the acoustic nerve, which prevents sound signals from reaching the brain. Also known as nerve deafness or retrocochlear hearing loss, the damage is for the most part permanent, although breakthroughs in modern technology have enabled some previously untreatable cases to be improved. The most frequent reasons behind sensorineural hearing loss are the aging process, extended exposure to noise, complications with blood circulation to the interior of the ear, fluid disturbance in the inner ear, medications that cause injury to the ear, a small number of diseases, genetics and problems with the auditory nerve. Hearing aids are adequate for the majority of people who have this sort of hearing loss, but in more serious cases, a cochlear implant may help restore hearing to those for whom a standard hearing aid is not enough.
- Central hearing loss – Central hearing loss occurs when a problem in the CNS (central nervous system) keeps sound signals from being processed by the brain. Affected individuals can seemingly hear just fine, but cannot decode or interpret what the speaker is saying. Many cases involve a problem with the person’s ability to adequately filter competing sounds. For instance, the majority of us can hold a conversation with traffic noise in the background, but individuals with this problem have a difficult time doing so.
- Mixed hearing loss – As the term suggests, mixed hearing loss is a blend of different types of hearing loss – conductive and sensorineural hearing loss. Although there are a few other types of hearing loss, the combination of these two is most frequent.
- Functional hearing loss – An infrequent situation, functional hearing loss is not physical. This condition is due to psychological or emotional problem in which the person’s physical ability to hear is normal, but they do not seem to be able to hear.