Otosclerosis is a hearing disorder that results from abnormal bone growth in the middle ear. This prevents the ear bones from vibrating as they normally would, disrupting the ability of sound waves to travel from the middle ear to the inner ear and causing progressive hearing loss. It often begins in the early 20s, and is the most common cause of hearing loss in young adults.

Causes & Symptoms

Otosclerosis develops when the stapes, a bone in the middle ear that normally vibrates when struck by sound waves, becomes stuck in place. The reason for this occurrence is unknown; researchers surmise it may be the result of a prior measles infection, stress fracture, or immune disorder. Heredity may also play a role, as it often runs in families. Caucasians, women, those who are pregnant, and individuals with a family history of hearing loss are at highest risk.

Hearing loss is the main symptom of otosclerosis. It starts out slowly, but worsens over time, and may affect one ear or both. Other possible symptoms include tinnitus, vertigo or dizziness, and balance problems.

Diagnosis & Treatment

Because otosclerosis presents symptoms similar to those found in other conditions, an examination by a qualified ENT specialist must be done to rule out other health conditions. Hearing tests measuring hearing sensitivity and sound conduction are helpful, as they will indicate hearing loss in the lower frequencies, a common sign of otosclerosis. An MRI or CT scan can also prove helpful.

Treatment depends on the severity of the condition. Mild cases often benefit from hearing aids. A surgical procedure known as a stapedectomy is often required, as well. This involves insertion of a prosthetic device into the middle ear that allows sound to bypass the rigid bone and permit sound waves to pass. This is often enough to restore hearing.