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Otosclerosis

By

Richard T. Miyamoto

, MD, MS, Indiana University School of Medicine

Last full review/revision Mar 2022| Content last modified Mar 2022
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Otosclerosis is a disease of the bone of the otic capsule that causes an abnormal accumulation of new bone within the oval window.

In otosclerosis, the new bone traps and restricts the movement of the stapes, causing conductive hearing loss Pathophysiology Pathophysiology . Otosclerosis also may cause a sensorineural hearing loss Hearing Loss Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss (1). More than 10% of people in the US have some degree of hearing loss that compromises their... read more Hearing Loss , particularly when the foci of otosclerotic bone are adjacent to the scala media. Otosclerosis tends to run in families, and half of all cases are inherited. There is a 25% chance of developing otosclerosis if one parent has it and a 50% chance if both parents have it. Otosclerosis is a complex disease with rare autosomal dominant forms caused by a single gene. By linkage analysis, the localization of an otosclerosis gene is chromosome 15q25-q26. The measles virus plays an inciting role in patients with a genetic predisposition for otosclerosis.

Although about 10% of White adults have some otosclerosis (compared with 1% of Blacks), only about 10% of affected people develop conductive hearing loss. Hearing loss caused by otosclerosis rarely may manifest as early as age 7 or 8, but most cases do not become evident until the late adolescent or early adult years, when slowly progressive, asymmetric hearing loss is diagnosed.

A hearing aid may improve hearing. Alternatively, stapedectomy to remove some or all of the stapes and to replace it with a prosthesis may be beneficial, but the risks of hearing loss and impaired vestibular function need to be considered.

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