Otosclerosis

Bone growth fixing the stapes, causing conductive hearing loss

Overview

Otosclerosis is abnormal bone remodelling in the otic capsule, the dense bone surrounding the inner ear. Most often the new bone fixes the footplate of the stapes, the smallest bone in the body, in the oval window, preventing it from transmitting vibrations and causing progressive conductive hearing loss, frequently in both ears. It commonly becomes apparent in young adulthood, is more often diagnosed in women, runs in families, and may worsen during pregnancy. Some people notice paracusis of Willis, hearing speech better in noisy surroundings. When the process extends into the cochlea it can add a sensorineural component. A characteristic dip in bone conduction near 2 kHz on the audiogram is known as the Carhart notch. Hearing aids are widely used, and stapes surgery, stapedotomy or stapedectomy, replaces the fixed stapes with a prosthesis and often restores much of the lost hearing. It is relatively common in people of European descent and less common in other populations.