While our ears provide access to speech, music, and the sounds of nature, they also bring noise into our lives. Hearing loss from environmental sounds of lawn mowers, rock music, and machinery increases with age, as the various parts of the ear become less responsive. Understanding the ill effects of noise has brought new safety practices and changes in the design of hearing aids.

In the 1950s, few people thought about hearing protection or considered wearing safety gear. As awareness of hearing loss from environmental noise grew, labor unions, manufacturers, the government, and company managers added noise pollution to the list of workplace hazards. The result was a new market for auditory protection, with decibel-blocking capacities suited to the needs of the wearer. Mechanical and prosthetic aids also have been developed to simulate or restore hearing.

The gradual reduction in size of hearing aids, a direct result of changes in technology, has produced devices that are barely noticeable to observers.

First attempted in the 1950s, cochlear implants are surgically inserted in the inner ear. There they transmit electrical impulses directly to the brain along the auditory nerve and make the wearer conscious of sound. This technology has been controversial since its approval by the FDA in 1984 because of questions of appropriate recipients, the age at which the procedure should be done, and whether deafness is a disability in need of correction at all or simply a different way of experiencing the world.