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Resource Center for the Deaf and Hard of Hearing

There are between 22 million and 36 million deaf or hard-of-hearing Americans, or ten to 17 percent of the U.S. population. Of those considered hard-of-hearing, 1.5 million are deaf and 1.5 million are late deafened. A person is considered “deaf” when he cannot hear well enough to use his hearing as a means of processing information. The “Deaf” (written with a capital “D”) are those who use American Sign Language (ASL) as their primary means of communication and share a culture. “Hard-of-hearing” can refer to a person with any degree of hearing loss who uses speech as a primary means of communication; this can refer to people who have completely lost their hearing after learning to speak. Another definition of classifies people who can hear well enough to rely on their hearing to process information and who communicate primarily through speech as “hard-of-hearing”. People who lose their hearing as adults are sometimes referred to as “late deafened”.

Classification and Quantification

One way hearing loss is classified is by cause. Conductive hearing loss refers to the loss or reduction of hearing caused by inefficient conduction of sound from the outer ear into to the eardrum. Those affected by conductive hearing loss will experience reduced sound levels or lose their ability to hear faint noises. Some causes of conductive hearing loss include middle-ear pathologies (such as ear infections, perforated eardrums, or tumors), infections of the ear canal, or malformations of the ear. Some causes of conductive hearing loss, such as the presence of a foreign body or impacted ear wax, can be corrected. The other form of hearing loss is sensorineural hearing loss. This refers to permanent hearing loss due to damage to the inner ear or nerve pathways to the brain from the inner ear. People with sensorineural hearing loss experience a reduction in sound levels and a loss of ability to hear faint sounds, as well as impaired ability to understand speech and to hear clearly. Causes of sensorineural hearing loss include birth injury, genetic syndromes, certain drugs, diseases, aging, trauma, and noise exposure. The severity of hearing loss, or its quantification, is measured by the softest intensity at which a person can perceive sound. Hearing loss can be characterized as slight (16 to 25 decibels), mild (26 to 40 dB), moderate (41-55 dB), moderately severe (56-70 dB), severe (71-90 dB), and profound (91+ dB).


Deafness and hearing loss result from a variety of causes. Congenital deafness is present at birth and can be caused by deformity of the ear, through genes inherited from parents, or through a non-hereditary genetic syndrome such as CHARGE syndrome, Mohr-Tranebjaerg syndrome, Usher syndrome, Waardenburg syndrome, and Jervell and Lange-Nielsen syndrome. Age-related hearing loss, or presbycusis, is a gradual decrease in hearing ability. Trauma, such as severe blows to the head or ear or perforated eardrums can cause sudden deafness. Other trauma, such as a fractured skull or damage to the head or jaw, can damage the bones of the ear and cause hearing loss. Certain drugs or chemicals, called ototoxic drugs, can cause deafness by damaging the cochlea or auditory nerve. Diseases that can result in deafness or hearing loss include rubella, mumps, influenza, severe jaundice, cytomegalovirus, otosclerosis, rheumatoid arthritis, lupus, and middle ear infections. Noise-induced deafness occurs when a person has repeated exposure to loud noises, such as in a noisy work environment. Auditory trauma, or exposure to an extremely loud noise such as a gunshot or explosion, can perforate the eardrum and require medical or surgical repair, but rarely results in permanent hearing loss.


Management and treatment of hearing loss depends on the classification and quantification of hearing loss, the patient’s age, expectations, and preferences. For children born hard-of-hearing or deaf, early intervention programs help children learn sign language, lip reading, or use hearing aids or assistive listening devices. Assistive listening devices are often called “FM units” and transmit sounds from a speaker’s microphone to the listener’s ear. Analog hearing aids amplify sounds and can be programmed for optimal performance in different listening environments. Digital hearing aids not only amplify sound, but reproduce the original sounds and can be programmed to automatically match the listening environment. Many other assistive devices are available for Deaf and hard-of-hearing people. Vibrating or flashing alarm systems take the place of traditional alarm clocks, baby monitors, telephone ringers, doorbells, and fire alarms. Text telephones and relay systems allow the Deaf to communicate via telephone by typing and receiving the caller’s verbal communication on a small screen.

Cochlear implants can be an option for the severely hard-of-hearing and deaf. Cochlear implants are tiny electronic devices comprising a microphone, a speech processor, a transmitter and receiver, and an electrode array that bypass the damaged portion of the ear and send electrical signals directly to the auditory nerve, which then interprets the signals as sounds. Cochlear implants require surgery and extensive therapy and training. Cochlear implants and some other medical treatments for deafness are not accepted or promoted by some members of the Deaf community who view deafness not as a handicap to “fix” but as a culture with its own language, schools, literature, film, programming, and group that should be preserved and valued.

Additional Resources

The original deaflinx.com site was written and authored by Amy Frasu. Deaf Linx is now run by Ericka Wiggins. Here are the Facebook and Twitter pages for Deaf Linx.