Overview

A picture of a human ear with a hand gesture indicating the person is listening.

What is Otosclerosis?

Otosclerosis is an example of a vestibular disorder that can lead to hearing loss. The name itself, Oto (Greek for ear) and sclerosis (what medical professionals generally call the process of organ and tissue hardening) implies an abnormal growth of bone in the inner ear. Generally speaking, we are talking about a hardening processes inside the ear preventing hearing systems from functioning properly. Let’s take an even closer look:

To understand this condition we have to know how sound is transmitted in the human ear. Sound first hits the ear drum and is then transmitted to the inner ear via the ossicles in the middle ear. It works its way there via the hammer, anvil and stirrup. These three ossicles must be flexible and able to vibrate to transmit sound. Sound is then transmitted from the stirrup to the inner ear via a transition area. This function is impaired in persons suffering from otosclerosis. The stirrup is most often affected by ossification, where it becomes inflexible. This inflexibility results in hearing loss as no sufficient signal can be passed on to the cochlear in the inner ear.

What Causes Otosclerosis?

Up to this day, it is not entirely clear what causes otosclerosis. There are, however, several factors that are believed to contribute to its development.

Many suspect a genetic component that is passed down through a family as scientists have found evidence of family predisposition. Differences can also be found between the sexes: This condition is twice as common among women as opposed to men. Since it is commonly aggravated during pregnancy, hormonal influences are also regarded as a cause of this condition. Finally, the measles virus is believed to be a potential cause.

Unfortunately, at this time there are no known measures to prevent otosclerosis.

What are the Symptoms of Otosclerosis?

The condition usually manifests itself as increasing deafness occurring between the ages of 20 and 50. Otosclerosis is identified as the cause of 5 to 9 percent of all hearing impairments. Among patients suffering from conductive deafness ossification is actually the cause in 18 to 22 percent of cases. Usually, impaired hearing initially affects one side, but can spread to both ears over time. Often, the patient’s ears are affected to varying extents. Furthermore, some patients report that they can hear better in loud environments. Other possible symptoms include tinnitus (most often in the range of low sounds) and dizziness. Since this hardening process takes place over the course of a long period, otosclerosis can remain undetected for years before the experiencing hearing loss. Sufferers usually don't feel any pain.
It’s best to consult an audiologist. In rare cases, examinations of the ear drum, middle ear and auditory tube show no signs of the condition, but the Schwartze Sign can still be diagnosed as a symptom of hardening. The Schwarze Sign is a reddening in the tympanic cavity seen through the ear drum.

The condition is not easy to detect, but it can be identified by means of various audiometric measurements (tone air threshold audiometry and impedance audiometry). In certain cases, further tests such as balance tests, x-rays of the ear region or a tympano-cochlear scintigraphy (TCS) might be required to diagnose the active center of inflammation.

How is Otosclerosis Treated?

An operation is the only way to successfully treat otosclerosis. The chances of recovery are very high: More than 90 percent of otosclerosis patients report improved hearing after the operation and about half are permanently cured of tinnitus. Therapies using medication, on the other hand, have shown little success.
Audiologist checking a patient's ear for hearing loss.
An operation is the only way to successfully treat otosclerosis. The chances of recovery are very high: More than 90 percent of otosclerosis patients report improved hearing after the operation and about half are permanently cured of tinnitus. Therapies using medication, on the other hand, have shown little success.

Today, the primary method is the stapedotomy. During a stapedotomy just the upper part of the stirrup is removed – while the footplate remains. Using a laser beam or small needle, the surgeon drills a tiny hole into the footplate and a prosthetic is inserted. Today, this method is the most widely used as it results in fewer complications. Laser stapedotomy is regarded as particularly precise.
The implanted prosthetics help directly conduct the oscillations of the ossicular chain to the inner ear. This bypasses the removed stirrup and the oscillations of the other, healthy ossicles are conducted to the prosthetic.
Such an operation can be performed under local or general anesthesia. For further information on the procedure and the risks of the operation please ask an audiologist.
Patients who only suffer from minor hearing loss should also consider hearing aids as an alternative to improve their hearing. This will not put a halt to the process of increasing ossification, however, they can improve hearing and quality of life before surgery is required. Regardless, regular hearing checks will be necessary.

Summary

Generally, ossification of the ear can be treated very well. Consult an audiologist if you notice signs of reduced hearing on yourself. Hearing loss can be a sign of many conditions and should always be looked at by a specialist.