CT/MRI: Otosclerosis

What is it?

Otosclerosis is the abnormal growth of spongy bone in the middle ear that causes structures to not properly work, resulting in conductive hearing loss. Depending on where in the ear the growth is occuring, different kinds of hearing loss can occur. Usually, otosclerosis affects the stapes that is located in the entrance

to the inner ear, also called the oval window. The abnormal growth causes the stapes to become attached in the oval window, and sound waves are obstructed from entering the inner ear. Otosclerosis may sometimes impair sensory cells or nerve fibers in the inner ear resulting in sensorineural hearing loss, making the level of hearing loss higher.

What causes it?

Some studies have shown that otosclerosis may be hereditary. A person that has one parent having the disease is 25% more likely to get it, and a person with both parents having the disease is 50% more likely to have it passed on to them. White, middle aged women are more susceptible to it than others. Research proposes that there may be a connection between otosclerosis and pregnancy hormonal changes, and a link between the disease and some viral infections.

What are the symptoms?

The most frequent and obvious sign of otosclerosis is hearing loss. It may start out as an overlooked loss of hearing of low pitched sounds, but it can gradually become worse until it is very severe. Some people may also experience dizziness, issues with balance, or tinnitus.

How is it diagnosed?

People who suffer from the symptoms of otosclerosis will need to see a physician specializing in the ear, an otologist for example, to rule out other illnesses or diseases. the physician may send the patient to an audiologist to diagnose, assess, and rehabilitate impairment of hearing and balance using tests. An audiogram is a graph that shows hearing sensitivity. A tympanogram is a graph that shows the functional ability of the middle ear to carry sound.

How is it treated?

If the hearing loss is mild and the person chooses not to opt to measures such as surgery, a hearing aid may be used to amplify sound. In many cases though, surgery is the first option for the complete treatment of otosclerosis, although some hearing loss can persist post-surgery.
Sometimes a stapedectomy is performed. In this operation, a surgeon removes the old stapes and inserts a prosthetic device that transfer sound waves to the inner ear.