Otosclerosis

Otosclerosis is the abnormal growth of bone of the inner ear. This bone prevents structures within the ear from working properly and causes different types of hearing loss, depending on which structure within the ear is affected. It typically affects the stapes, a tiny bone in the middle ear which rests in the oval-shaped opening between the middle and inner ear (the oval window). The abnormal bone fixates the stapes in the oval window and interferes with sound passing waves to the inner ear.

The cause of otosclerosis is not fully understood, although research has shown that it tends to run in families and may be hereditary. On average, a person who has one parent with otosclerosis has a 25 percent chance of developing the disorder, and if both parents have otosclerosis, the risk goes up to 50 percent. Research shows that white, middle-aged women are most at risk.

Hearing loss is the most frequent symptom of otosclerosis. The loss may appear very gradually. Many people with otosclerosis first notice that they cannot hear low-pitched sounds or they can no longer hear a whisper. In addition to hearing loss, some people with otosclerosis may experience dizziness, balance problems, or tinnitus (a sensation of ringing, roaring, buzzing, or hissing in the ears).

In order to diagnose otosclerosis, an examination by an otolaryngologist or otologist is needed to rule out other diseases or health problems that may cause these same symptoms. In addition, an audiologist may test hearing sensitivity and a how well the middle ear conducts sound.

Surgery is frequently an option for treatment of otosclerosis. In an operation called a stapedectomy, the diseased bone is bypassed with a prosthetic device that allows sound waves to be passed to the inner ear. In rare cases, surgery can worsen the hearing loss. If the hearing loss is mild, surgery may not be an option. A properly fitted hearing aid may help some people with otosclerosis in situations that include persistent hearing loss.

Genetic studies are ongoing that aim to identify the gene or genes that may lead to this disorder. Research is also being conducted on the effectiveness of lasers currently used in surgery, of amplification devices, and of various stapes prostheses.