What is Otosclerosis?
The term otosclerosis is taken from the Greek oto (ear) and sclero (hard). In otosclerosis, the sound-conducting bones of the middle ear change from dense, mineralized bone to spongy, immature bone tissue. This abnormal bone growth may lead to fixation of one of the middle ear bones, the stapes or stirrup. This bone must move freely in order for the auditory system to work properly.
Hearing is a complex process. In a normal ear, sound waves travel through the ear canal where they strike the eardrum, causing it to vibrate. These vibrations are transferred to the three small bones of the middle ear, the malleus (hammer), incus (anvil) and stapes (stirrup). When the stapes vibrates, it sets up a pressure wave in the inner ear which stimulates the auditory nerve to produce an electrical impulse. The auditory nerve carries this energy to the brain, resulting in the perception of sound. When any part of this process is compromised, hearing loss results.
About 10% of the adult Caucasion population is affected by otosclerosis. The condition is less common in people of Japanese and South American ancestry, and is rare in African Americans.
Approximately twice as many women as men are diagnosed with otosclerosis. This is possibly because pregnancy and hormonal changes seem to accelerate the progression of the disease.
Age: The incidence of otosclerosis increases with age
Family history of otosclerosis
Race: Caucasian or non-Japanese Asian
Drinking non-fluoridated water
Multiple pregnancies, although the correlation between pregnancy, hormones, and otosclerosis has recently been questioned
Signs and Symptoms
Gradual hearing loss
Difficulty hearing low-pitched sounds or whispers
Dizziness or balance difficulties
Tinnitus, or ringing, roaring, or buzzing in the ears
If hearing loss is mild, your physician may suggest continued observation and a hearing aid to amplify sound. Some research suggests that sodium fluoride may slow the progression of the disease. In most cases, surgery to replace the diseased bone (stapedectomy) may be the best way to restore hearing, with a success rate of 90%. Rarely (about one percent of surgeries), the procedure may make hearing worse.
There is no proven way to prevent otosclerosis. Fluoride tablets are sometimes prescribed to stabilize the condition; however, this treatment is controversial. Research does suggest that drinking fluoridated water may help prevent the disease in susceptible individuals. There are no other known ways of preventing otosclerosis.
Consulting ear-nose-throat physician
Health Professionals by Specialty
Boystown National Research Hospital
Self-Help for Hard of Hearing People, Inc.
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