What is Otosclerosis: Causes, Symptoms & Treatment

Hearing plays an important role in how we communicate and experience the world around us. However, certain conditions can gradually affect our ability to hear. One such condition is otosclerosis, a disorder of the middle ear that can lead to progressive hearing loss.

What is Otosclerosis?

Otosclerosis refers to an abnormal bone growth in the middle ear that commonly affects the stapes, a tiny bone also known as the stirrup. This bone is responsible for passing sound vibrations from the middle ear to the inner ear.

When abnormal bone tissue forms around the stapes, it can become fixed or immobile. This prevents it from vibrating properly in response to sound waves, making it difficult for sound signals to reach the inner ear. As a result, hearing gradually declines.

How Does Otosclerosis Cause Hearing Loss?

In a healthy ear, sound travels through the ear canal to the eardrum and then through three tiny bones in the middle ear, the malleus, incus, and stapes. These bones amplify sound and transmit it to the inner ear.

In otosclerosis:

• Abnormal bone growth develops around the stapes.
• The stapes become stiff and cannot vibrate freely.
• Sound transmission to the inner ear becomes impaired.

This leads to conductive hearing loss, meaning sound cannot effectively pass through the middle ear.

In some advanced cases, the inner ear may also be affected, leading to mixed hearing loss (both conductive and sensorineural).

What Causes Otosclerosis?

The exact cause of otosclerosis is not always clear, but several factors may contribute:

• Genetic predisposition: The condition often runs in families.
• Hormonal factors: It is more commonly seen in women and may worsen during pregnancy.
• Viral infections: Some studies suggest a link with certain viral infections.
• Abnormal bone remodelling: Changes in how bone tissue renews itself can lead to excessive bone formation.

Symptoms of Otosclerosis

Otosclerosis typically develops slowly, and symptoms may worsen over time. Common symptoms include:

• Gradual hearing loss, often starting in one ear and later affecting both
• Difficulty hearing low-pitched sounds
• Tinnitus (ringing or buzzing in the ear)
• Feeling of fullness in the ear
• Improved hearing in noisy environments (a phenomenon known as paracusis Willisii)

In rare cases, mild dizziness or balance problems

Who is at Risk?

Certain groups may have a higher risk of developing otosclerosis:

• Individuals with a family history of the condition
• Women between 20 and 40 years of age
• People of Caucasian descent (though it can occur in any population)
• Individuals with a history of measles infection

Diagnosis

An ENT specialist may diagnose otosclerosis using several tests:

• Hearing tests (audiometry) to measure the degree and type of hearing loss
• Tympanometry to evaluate middle ear function
• CT scan of the temporal bone to detect abnormal bone growth in the middle ear

Early diagnosis helps determine the most effective treatment plan.

Treatment Options

Treatment depends on the severity of hearing loss and the patient’s overall health.

Hearing Aids

For mild to moderate hearing loss, hearing aids can help amplify sound and improve hearing ability.

Medications

In some cases, medications like sodium fluoride or bisphosphonates may be used to slow the progression of abnormal bone growth, though their effectiveness varies.

Stapedectomy Surgery

This is the most common surgical treatment for otosclerosis. During the procedure:

• The immobilised stapes bone is partially or completely removed.
• It is replaced with a tiny prosthetic device.
• This prosthesis restores sound transmission to the inner ear.
• Most patients experience significant improvement in hearing after surgery.

When Should You See a Doctor?

Consult an ENT specialist if you notice:

• Gradually worsening hearing loss
• Persistent ringing in the ears
• Difficulty understanding conversations
• Hearing better in noisy environments than in quiet settings

Early evaluation can prevent further hearing deterioration and improve treatment outcomes.

Conclusion

Otosclerosis is a treatable cause of hearing loss. While it can progress over time, modern diagnostic tools and treatment options, especially hearing aids and stapedectomy surgery, offer effective solutions for restoring hearing and improving quality of life.

If you or a loved one is experiencing symptoms of hearing loss, seeking timely medical advice can make a major difference in managing the condition and preserving hearing health.