Otosclerosis

Otosclerosis is an abnormal bone-remodeling disorder that affects the structures surrounding the middle and inner ear. In many cases, abnormal bone growth causes the stapes, the smallest of the three middle-ear bones, to become less mobile or fixed in position. Because the stapes normally transfers vibrations from the middle ear into the inner ear, restricted movement can interfere with the transmission of sound and cause hearing loss.

The condition often develops gradually, and hearing loss may initially be subtle. It can affect one ear or both ears and may progress over time. While otosclerosis primarily produces conductive hearing loss, some individuals can develop involvement of the inner ear that contributes to sensorineural hearing loss.

The exact cause of otosclerosis is not fully understood. Researchers believe that abnormal bone remodeling plays a central role, and many cases appear to have a hereditary component. Other proposed factors have been studied, including previous measles infection and immune-related mechanisms, but the underlying cause is not established in every patient.

Otosclerosis can occur in people without a known family history, so the absence of affected relatives does not rule it out. If multiple family members have experienced unexplained hearing loss, however, a hereditary form of otosclerosis may be considered as part of the evaluation.

Otosclerosis can affect people of different ages and backgrounds, but it is often diagnosed in adulthood and has historically been reported more frequently in women and people of European ancestry. Family history is also an important consideration because the condition can run in families.

The presence of these risk patterns does not establish a diagnosis. Hearing loss can have many causes, so an audiologic and medical evaluation is necessary to determine whether the hearing changes are consistent with otosclerosis or another ear condition.

Progressive hearing loss is the most common symptom of otosclerosis. Hearing changes often develop gradually, and some people initially notice difficulty hearing low-pitched sounds or soft speech before realizing that their overall hearing has changed. The hearing loss may begin in one ear and later affect the other.

Other symptoms may include:

• Hearing loss in one or both ears
• Difficulty hearing soft or low-pitched sounds
• Tinnitus, such as ringing, buzzing, hissing, or rushing sounds
• A sensation that sounds are unclear or muffled
• Balance symptoms or dizziness in some individuals

Not everyone with otosclerosis experiences the same symptoms. Hearing loss is the primary concern, and symptoms such as tinnitus or dizziness can also occur with many other ear disorders. This is why a comprehensive evaluation is important before attributing symptoms to otosclerosis.

To understand hearing loss from otosclerosis, it helps to understand how sound normally travels through the ear. Sound enters the ear canal and causes the eardrum to vibrate. Those vibrations are transferred through the three middle-ear bones, the malleus, incus, and stapes, before reaching the inner ear. The inner ear then converts those vibrations into electrical signals that travel through the auditory nerve to the brain.

When otosclerosis causes the stapes to become fixed or less mobile, sound cannot be transferred efficiently into the inner ear. This produces conductive hearing loss because the problem occurs in the mechanical transmission of sound rather than the initial detection of sound by the inner ear. If otosclerosis also affects the inner ear, a sensorineural component may develop.

Otosclerosis is a common cause of conductive hearing loss because abnormal bone remodeling can prevent the stapes from moving normally. When the stapes cannot efficiently transmit vibrations to the inner ear, hearing sensitivity decreases even though the inner ear may initially remain functional.

Some patients may have a mixed hearing loss if the condition affects both middle-ear sound transmission and inner-ear function. The distinction matters because the type and degree of hearing loss help determine whether hearing aids, surgery, or another treatment approach is most appropriate.

Diagnosing otosclerosis begins with a medical and audiologic evaluation. Your physician or audiologist will review your symptoms, hearing history, family history, and any other ear-related concerns before examining the ears and evaluating how sound is traveling through the auditory system.

A typical evaluation may include:

• Pure-tone audiometry to measure hearing sensitivity across different frequencies
• Speech testing to evaluate how well you detect and understand speech
• Tympanometry to assess middle-ear function and sound transmission
• Examination of the ear canal and eardrum
• Additional audiologic testing when appropriate
• CT imaging in selected cases when additional information about the middle and inner ear is needed

Otosclerosis can resemble other causes of conductive or mixed hearing loss, so diagnosis involves ruling out other conditions that could produce similar hearing-test results. NIDCD notes that audiometry and tympanometry are commonly used in the evaluation, while CT may sometimes be used to help diagnose the condition.

An audiogram measures how well you hear sounds at different frequencies and helps determine the degree and type of hearing loss. In people with otosclerosis, testing may show a conductive hearing loss pattern, although the results can vary depending on how extensively the condition has affected the middle and inner ear.

Your audiologist will interpret the complete hearing profile rather than relying on a single number or frequency. Additional testing can help determine whether the hearing loss is primarily conductive or whether there is also a sensorineural component, which can affect treatment recommendations.

Treatment for otosclerosis depends on the degree and type of hearing loss, the symptoms you are experiencing, the condition of the affected ear, and your treatment goals. There is currently no established medication that reliably reverses the abnormal bone remodeling responsible for otosclerosis. For patients with hearing loss that affects communication, the primary treatment options are generally hearing aids or surgery.

Treatment may include:

• Monitoring mild or stable hearing loss
• Hearing aids
• Stapedotomy or stapedectomy
• A combination of surgical treatment and hearing technology when appropriate
• Ongoing hearing evaluations to monitor changes

Your ENT physician and audiologist can discuss the potential benefits and limitations of each approach based on your individual hearing results.

Hearing aids can be an effective treatment for people with otosclerosis, particularly when hearing loss is mild or when surgery is not appropriate or not preferred. A hearing aid amplifies sound according to your hearing profile and can improve access to speech and environmental sounds without surgically altering the middle ear. NIDCD identifies hearing aids as a treatment option for mild otosclerosis.

The appropriate hearing aid depends on the degree and configuration of your hearing loss as well as your communication needs. Some people may use hearing aids successfully for many years, while others may choose surgery to address the mechanical problem causing the conductive hearing loss.

A stapedotomy is a surgical procedure used to treat conductive hearing loss caused by otosclerosis. During the procedure, the surgeon creates a small opening in the fixed stapes or its footplate and places a tiny prosthesis designed to transmit sound vibrations to the inner ear. By bypassing the portion of the stapes that is no longer moving normally, the procedure can improve the mechanical transmission of sound into the inner ear. The goal is to improve hearing while preserving the function of the inner ear and other delicate structures.

Stapedotomy is commonly discussed as a hearing-restoration option for appropriately selected patients with otosclerosis. As with any ear surgery, the potential benefits, risks, and expected hearing outcome should be reviewed carefully with an experienced ear surgeon before deciding on treatment.

A stapedectomy is another surgical procedure used to treat hearing loss caused by otosclerosis. In a stapedectomy, part or all of the stapes superstructure is removed and replaced or bypassed with a prosthesis that allows sound vibrations to reach the inner ear.

The terms stapedotomy and stapedectomy are sometimes used interchangeably in general discussions, but they describe somewhat different surgical techniques. Your ear surgeon can explain which procedure is appropriate based on the anatomy of your ear, the extent of the otosclerosis, and your hearing results.

Both stapedotomy and stapedectomy are designed to bypass the abnormal stapes and improve the transmission of sound to the inner ear. The primary difference is the surgical technique used to address the stapes and create a pathway for the prosthesis.

The choice between procedures is not simply a matter of choosing which operation is “better.” An experienced ear surgeon considers the patient’s anatomy, hearing profile, surgical history, and other clinical factors when determining the most appropriate technique.

Otosclerosis surgery is performed by an ear surgeon using specialized techniques designed to work around the delicate structures of the middle and inner ear. The surgeon accesses the middle ear, addresses the abnormal stapes, and places a prosthesis to restore the transmission of sound vibrations toward the inner ear.

Because the middle ear is located close to structures responsible for hearing and balance, the procedure requires precise surgical technique. Your surgeon will discuss the expected hearing improvement, limitations, recovery process, and potential complications before surgery.

Recovery varies from patient to patient, and your surgeon will provide specific instructions based on the procedure performed and your individual circumstances. Hearing may not return immediately, and it can take time for the ear to heal and for the final hearing result to become apparent.

Temporary changes in hearing, pressure, fullness, or balance can occur during the recovery period. Follow-up appointments allow your physician to monitor healing and assess the hearing outcome. You should follow your surgeon’s instructions regarding activity restrictions, keeping the ear dry, air travel, and other aspects of postoperative care.

Stapes surgery can provide substantial hearing improvement for appropriately selected patients with conductive hearing loss caused by otosclerosis. The degree of improvement varies depending on factors such as the extent of the disease, the condition of the inner ear, the surgical anatomy, and whether other types of hearing loss are also present.

Surgery does not guarantee completely normal hearing, and a sensorineural component of hearing loss may remain even when the conductive component is successfully treated. NIDCD also notes that some hearing loss can persist after surgery and that, rarely, hearing can worsen as a complication of the procedure.

Like any surgical procedure, stapes surgery has potential risks and limitations. Your surgeon should explain these risks in the context of your specific anatomy and hearing condition before treatment.

Potential complications can include:

• Persistent or incomplete hearing improvement
• Temporary or persistent dizziness
• Taste disturbance
• Tinnitus
• Prosthesis-related problems
• Need for additional treatment
• Rarely, significant or profound worsening of hearing

The overall risk profile depends on the individual patient and the specific procedure. A detailed consultation with an experienced ear surgeon is the best way to understand the potential benefits and risks in your case.

Yes. Some people with otosclerosis experience tinnitus, which may sound like ringing, buzzing, hissing, or rushing in the affected ear. Tinnitus can occur alongside hearing loss and may vary in severity from person to person.

When tinnitus is associated with hearing loss, treating the underlying hearing problem may reduce how noticeable the tinnitus is for some patients. However, tinnitus can have multiple causes, so persistent or bothersome tinnitus should be evaluated rather than automatically attributed to otosclerosis.

Some people with otosclerosis report dizziness or balance symptoms, although these symptoms are not specific to the condition. The inner ear contains structures responsible for both hearing and balance, and other ear disorders can produce similar symptoms.

If dizziness or vertigo occurs with hearing loss, your physician may recommend additional evaluation to determine whether otosclerosis is responsible or whether another balance or inner-ear disorder is contributing to the symptoms.

Otosclerosis can be progressive, meaning hearing loss may become more significant over time. The rate of progression varies considerably between individuals, and some people may have relatively stable hearing for extended periods.

Regular hearing evaluations can help identify changes and determine whether your current treatment remains appropriate. If hearing worsens despite hearing aids or if new symptoms develop, your treatment plan may need to be reassessed.

There is currently no established way to prevent otosclerosis. Because many cases appear to have a hereditary component, people with a family history of the condition may be more likely to develop it, but having a family history does not mean that hearing loss is inevitable.

Protecting your hearing from excessive noise remains important regardless of whether you have otosclerosis. Avoiding unnecessary noise exposure and using appropriate hearing protection can help reduce the risk of additional noise-related damage to the inner ear.

Gradually worsening hearing, particularly when it occurs without an obvious cause, should be evaluated by an audiologist or ENT physician. An evaluation is especially important if hearing loss affects one or both ears, continues to progress, or occurs with tinnitus, dizziness, or other ear symptoms.

If you have a family history of otosclerosis or have previously been diagnosed with the condition, periodic hearing evaluations can help monitor your hearing over time. Early evaluation can also help distinguish otosclerosis from other causes of conductive, sensorineural, or mixed hearing loss.