The Encyclopedia of Deafness and Hearing Disorders

The National Institute on Deafness and Other Communication Disorders reports that more than 28 million Americans are deaf or hard of hearing; over 30 million more are exposed to dangerous levels of noise. Levels of hearing impairment vary from mild but important loss of sensitivity to a total loss of hearing. According to the American Speech-Language-Hearing Association, almost 13 in every 1,000 children under age 18 has some degree of hearing loss as do approximately 54 percent of adults over a