Hearing Loss & Deafness Support Group

Hearing loss can also differ in what pitches (frequencies) are affected. Human beings generally are sensitive to even quiet sounds, as long as the sounds are at certain pitches: ranging from about 125 Hz to 8000 Hz. The "human ear" is best tuned to pick up sounds at the same pitches (frequencies) as speech, from about 500 to 4000 Hz. The blast of a dog whistle is not heard well even by people with normal hearing because it makes a sound that is at a very high frequency, above the normal human range. Some people do not hear well throughout this range, but are "hard of hearing" depending on the pitch of the sound (low frequency hearing loss, high frequency hearing loss, mid-frequency or U-shaped hearing loss).

Hearing impairment comes from different causes. Most commonly, the ear is affected. Conductive hearing losses involve clogging or abnormalities of the outer or middle ear, and only produce mild or moderate impairment, at worst. Hearing loss due to insensitivity of the inner ear, the cochlea, can also be only mild or moderate but can also be much more severe, even causing complete insensitivity to even the loudest sounds (total deafness . Very unusual hearing impairments involve the auditory portions of the brain.

There are three major types of hearing loss: neural/sensorineural, conductive, or a combination of both. Treatment depends upon the type of hearing loss that is present.

Sensorineural hearing loss is caused by damage/malfunction of the inner ear (cochlea, eighth cranial nerve) or auditory brainstem. This can be divided further into a sensory hearing loss (inner ear) or a neural hearing loss (brainstem).

Conductive hearing loss is caused by damage/malfunction of the middle or outer ear system (external ear canal, ear drum, or structures in the middle ear space including the malleus, incus and stapes bones).

Mixed hearing loss is caused by both conductive and sensorineural causes.

In addition to hearing aids there exist cochlear implants of increasing complexity and effectiveness. These are useful in treating the mild to profound hearing impairment when the onset follows the acquisitions of language and in some cases in children whose hearing loss came before language was acquired. Recent research shows variations in effacacy but some promising studies[7] show that if implanted at a very young age, some profoundly impaired children can acquire effective hearing and speech.