Hearing impairment occurs when there’s a problem with or damage to one or more parts of the ear. There are many types of hearing impairments
Conductive hearing loss results from a problem with the outer or middle ear, including the ear canal, eardrum, or ossicles. A blockage or other structural problem interferes with how sound gets conducted through the ear, making sounds seem quieter. In many cases, conductive hearing loss can be corrected with medications or surgery.
Sensorineural (pronounced: sen-so-ree-nyour-ul) hearing loss results from damage to the inner ear (cochlea) or the auditory nerve. The most common type is caused by the outer hair cells not functioning correctly. The person has trouble hearing clearly, understanding speech, and interpreting various sounds. This type of hearing loss is permanent. In many cases, hearing aids can help the person hear normally.
In more severe cases, both outer and inner hair cells aren’t working correctly. This is also a type of permanent hearing loss and usually people can benefit from cochlear implants. In some other cases, the outer hair cells work correctly, but the inner hair cells or the nerve are damaged. This type of hearing loss is called auditory neuropathy spectrum disorder. The transmission of sound from the inner ear to the brain is then disorganized.
Children with auditory neuropathy spectrum disorder can develop strong language and communication skills with the help of medical devices, therapy, and visual communication techniques.
Mixed hearing loss happens when someone has both conductive and sensorineural hearing problems.
Central hearing loss happens when the cochlea is working properly, but other parts of the brain are not. This is a less frequent type of hearing loss and is more difficult to treat.
Auditory processing disorders (APD). This is not exactly a type of hearing loss because someone with APD can usually hear well in a quiet environment. But most people with APD have difficulty hearing in a noisy environment, which is the usual environment we live in. In most cases, APD can be treated with proper therapy.
The degree of hearing impairment can vary widely from person to person. Some people have partial hearing loss, meaning that the ear can pick up some sounds; others have complete hearing loss, meaning that the ear cannot hear at all (people with complete hearing loss are considered deaf). In some types of hearing loss, a person can have much more trouble when there is background noise. One or both ears may be affected, and the impairment may be worse in one ear than in the other.
The timing of the hearing loss can vary, too. Congenital hearing loss is present at birth. Acquired hearing loss happens later in life — during childhood, the teen years, or in adulthood — and it can be sudden or progressive (happening slowly over time).