Otosclerosis

Definition:

An abnormal bone growth in the middle ear which causes hearing loss.

Causes, incidence, and risk factors:

Otosclerosis is an inherited disorder involving the growth of abnormal spongy bone in the middle ear. This growth prevents the stapes (stirrup bone) from vibrating in response to sound waves, thus leading to progressive conductive hearing loss.

Otosclerosis is the most frequent cause of middle ear hearing loss in young adults, affecting about 10% of the population of the U.S. Otosclerosis usually affects both ears, and is most commonly seen in women, 15 to 30 years old.

Risks include a family history of hearing loss and pregnancy (may trigger onset). Caucasians are more susceptible to otosclerosis than others.