About one-out-of-three Americans over the age of 60 have age-related hearing loss. The condition is known medically as prebycusis. It happens naturally with age. It can be caused by changes in the inner ear, auditory nerve, middle ear or outer ear. Some of its causes are aging, loud noise, heredity, head injury, infection, illness, certain prescription drugs, and circulation problems such as high blood pressure. Studies indicate it is probably inherited.