Much of the hearing loss associated with aging (called presbycusis) is the result of the loss of the hair cells that line the cochlea (the snail-shaped structure of the inner ear). As vibrations enter the cochlea, the hair cells normally register the motion and transmit impulses to the auditory nerve. When hair cells die, however, usually as a result of noise damage, they are not replaced. And, because hair cells that register high-frequency sound tend to be the most vulnerable to injury, we are most likely to lose the ability to detect high-pitched sounds first. People who suffer from presbycusis are less likely to discern children's and women's high-pitched voices. Fortunately, a hearing instrument may help.

For some people, hearing loss is a result of sound waves finding it impossible to reach their destination in the inner ear, Hearing loss is often a result of aging, although it can also be caused (or made worse) by illness, heredity, medications, injury, or prolonged exposure to loud noise.

P.S. Because presbycusis develops gradually, those who suffer from it may not notice a difference in their hearing ability until it is pointed out to them.