Many people think of hearing loss as a sign of advancing age. The fact is that persons of all ages can have hearing loss—even babies. Although 43 percent of Americans with hearing loss are 65 years or older, the prevalence of hearing loss among newborns is estimated to range between three and six per 1,000 births, and 11.5 percent of school children have some degree of hearing loss. Clearly hearing loss has no age constraints.

Although there are several types of hearing loss, generally they fall into one of three categories: conductive, sensorineural or mixed hearing loss, based on the location of the problem in the auditory system.

• Sensorineural hearing loss. A sensorineural loss occurs when there is damage to the inner ear and/or to the nerve pathways from the inner ear to the brain. Sensorineural losses usually result in both a reduction in sound level and inability to understand speech. The aging process, heredity, syndromes, birth defects, certain medications, head injury, tumors and repeated exposure to noise can lead to this type of hearing loss.
• Conductive hearing loss. A conductive hearing loss occurs when sound is not conducted efficiently through the ear canal, eardrum or tiny bones of the middle ear. Conductive losses primarily reduce the loudness of the sound that is heard.
• Mixed hearing loss. Some people have a conductive loss and a sensorineural loss in the same ear(s) at the same time (for example, an ear infection and noise-induced hearing loss). When this occurs, the hearing loss is referred to simply as "mixed."