Learn more about otosclerosis and how it is diagnosed and treated.
Otosclerosis is a condition caused by abnormal growth of the bone of the inner ear. The inner ear bone grows and affects the stapes (3rd hearing bone behind the ear drum) movement. While that growth allows the eardrum to continue to absorb sound, it also causes the ossicular chain to not move as well, so the sound can’t reach the cochlea. The result is hearing loss.
- Otosclerosis usually affects only one ear at first
- In 30% of individuals, it can affect both ears
The abnormal growth can also cause the stapes or other ear bones to not vibrate. Under normal conditions, the ear bones vibrate when they are transmitting sound. If they can’t vibrate, the sound doesn’t travel through the ear, and the patient can’t hear. The condition affects the patient’s ability to hear low-frequency sounds early on. During the disease’s later stages, the patient’s ability to hear high-frequency sounds is also impaired.
Otosclerosis affects about three million people in the United States. While patients can develop it between the ages of 10 and 45, most develop it during their 20s. A patient’s symptoms tend to be at their most severe when they are in their 30s. While anybody can get otosclerosis, the condition is most common in Caucasian women: about 10 percent will develop it. Ten percent of Caucasian men also develop otosclerosis. In both cases, permanent hearing loss affects ten percent of patients (10% of 10% meaning 1% of the overall population). Otosclerosis also affects certain subpopulations of India as well.
Otosclerosis is thought to be hereditary, which means it tends to run in families. Having a close relative with otosclerosis thus increases the chances of developing it. Certain viruses are also thought to be a potential cause of otosclerosis. The hormones produced during pregnancy cause the disease to progress more quickly, so a pregnant woman with otosclerosis is at a greater risk of developing hearing loss than is a man or a woman who is not pregnant.
Hearing loss is the chief symptom of otosclerosis. The patient will first notice that they are starting to have problems hearing whispers or low-pitched sounds. The hearing loss gets worse over time. Most of the time, the hearing loss affects both ears; in 70 percent of cases, only one ear is affected.
There are several treatment options. In mild cases, the doctor may recommend only monitoring to determine the rate of the disease’s progression. They will periodically test the patient’s hearing. The tests can include a physical examination of the ear and audiometry (hearing testing). The doctor may also order a CT scan. The different tests can also be used to rule out other causes of hearing loss like superior canal dehiscence, malleus fixation.
The doctor may also recommend a hearing aid. Hearing aids in general help about 90 percent of people with hearing loss, and there are several different types. It generally takes several weeks for the patient to get the full benefit from the hearing aid, for it will take that long for the patient to get accustomed to it and for the doctor to make the needed adjustments.
The type of hearing aid used will depend on the severity of the hearing loss and the patient’s lifestyle. The hearing aids inserted into the patient’s ear or ear canal will be custom-made to ensure a perfect a fit. An audiologist will work with the patient to help them make the best choice.
Some doctors may recommend a dietary supplement called sodium fluoride in patients with cochlear otosclerosis (when the otosclerosis bone involves the inside membrane portion of the inner ear).
The stapedectomy is a surgical procedure in which the doctor removes the stapes and replaces it with a prosthetic. The procedure takes less an hour and has a success rate of around 95 percent. The main complications associated with the stapedectomy are that the manipulations of the inner ear can cause constant dizziness and/or permanent hearing loss which can occur less than 1% of time.