Otosclerosis is a term derived from oto, meaning “of the ear,” and sclerosis, meaning “abnormal hardening of body tissue.” The condition is caused by abnormal bone remodeling in the middle ear. Bone remodeling is a lifelong process in which bone tissue renews itself by replacing old tissue with new. In otosclerosis, abnormal remodeling disrupts the ability of sound to travel from the middle ear to the inner ear. Otosclerosis affects more than three million Americans. Many cases of otosclerosis are thought to be inherited. White, middle-aged women are most at risk.