Otosclerosis is the abnormal growth of bone of the middle ear. This bone prevents structures within the ear from working properly and causes hearing loss. For some people with otosclerosis, the hearing loss may become severe. http://www.nidcd.nih.gov/health/hearing/otosclerosis.htm#1 Otosclerosis is an inherited disorder involving the growth of adnormal spongy bone in the middle ear.

The cause of otosclerosis is not fully understood, although research has shown that otosclerosis tends to run in families and may be hereditary, or passed down from parent to child. People who have a family history of otosclerosis are more likely to develop the disorder. On average, a person who has one parent with otosclerosis has a 25 percent chance of developing the disorder. If both parents have otosclerosis, the risk goes up to 50 percent.

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 that they can no longer hear a whisper. In addition to hearing loss, some people with otosclerosis may experience dizziness, balance problems, or tinnitus. Tinnitus is a sensation of ringing, roaring, buzzing, or hissing in the ears or head that accompanies many forms of hearing loss.

examination by an otolaryngologist (ear, nose, and throat physician) or otologist (ear physician) is needed to rule out other diseases or health problems that may cause these same symptoms. An audiologist is a hearing health care professional who is trained to identify, measure, and rehabilitate hearing impairment and related disorders. An audiologist uses a variety of tests and procedures to assess hearing and balance function.

In many cases surgery is an option for treatment of otosclerosis. In an operation called a stapedectomy, a surgeon (otolaryngologist or otologist) bypasses the diseased bone with a prosthetic device that allows sound waves to be passed to the inner ear. It is important to discuss the risks and possible complications of this procedure, as well as the benefits, with the surgeon. In rare cases, surgery can worsen the hearing loss. If the hearing loss is mild, surgery may not be an option.

Scientists are conducting research to improve understanding of otosclerosis. Genetic studies continue in order to identify the gene or genes that may lead to this disorder. Other researchers are studying the effectiveness of lasers currently used in surgery, of amplification devices, and of various stapes prostheses. Improved diagnostic techniques are also being examined and developed.

Otosclerosis can cause different types of hearing loss, depending on which structure within the ear is affected. Otosclerosis usually affects the last bone in the chain, the stapes, which rests in the entrance to the 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. Otosclerosis usually causes a conductive hearing loss, a hearing loss caused by a problem in the outer or middle ear.