Hearing impairments can be classified as either conductive or sensorineurial. Conductive hearing impairment occurs when this process is disrupted by an obstruction or damage to the outer and middle ear. Sensorineurial hearing impairments result from the destruction of little hairs in the inner ear or damage to the nerves that connect the inner ear to the brain.
The ability to hear sound is dependent on the efficient transfer of sound wave through the outer ear and eardrum to the middle ear then the inner ear. Common causes of conductive impairment and partial hearing loss are a buildup of earwax, an ear infection, and damage to the eardrum. Individuals affected by conductive hearing disabilities often find that the degree of hearing loss can be greatly alleviated with the use of hearing aids or, in many cases, completely repaired through surgery.
Sensorineurial hearing impairments are responsible for most instances of permanent hearing loss and deafness. The loss in hearing can range in severity from mild to profound. Inner ear damage that leads to loss of hearing is irreparable in most cases. Hearing disabilities of this type can be caused by hereditary factors, trauma or injury to the head, and aging. Hearing aids can amplify sounds for sufferers of moderate forms of hearing loss. Surgically-installed cochlear implants may help hard-of-hearing individuals with severe hearing loss.
Gradual hearing loss that develops as a result of degenerative factors such as aging and prolonged exposure to noise represents nearly half the cases of reported hearing disabilities in adults. These are instances of sensorineurial hearing impairment. Most hearing disabilities are not present at birth and usually develop later in life. Deafness in one or both ears rarely occurs, with most individuals experiencing partial hearing loss. Total or partial deafness in children is usually congenitally acquired, either from hereditary traits or due to complications during pregnancy.
Deafblindess refers to a dual sensory impairment where a hearing disability exists along with blindness. The extent of hearing loss and vision impairment in individuals who are deaf-blind can be severe enough to impede them from communicating by most normal means. The conditions of being deaf or hard of hearing and blind does not always occur simultaneously. In many instances individuals who are blind may experience hearing loss later down the road, and the reverse is true for people who are deaf and hard of hearing.