Otosclerosis: Causes, Symptoms and Treatments for Hearing Loss

How this middle ear condition causes progressive hearing loss and what you can do to restore it

Stephanie Watson,

AARP

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Published November 03, 2025

AARP (Getty Images)

Key takeaways

Otosclerosis is a progressive middle ear condition that causes hearing loss.
This condition runs in families and is more common in women.
Symptoms include feelings of fullness in the ear, dizziness and tinnitus.
An audiologist can usually diagnose otosclerosis with an exam or a hearing test.
Treatments include hearing aids and surgery to replace the stapes bone.

Every sound that surrounds you, whether it’s your favorite song or the neighbor’s dog barking, travels through your middle ear. There, a trio of bones — the malleus, incus and stapes (colloquially known as the hammer, anvil and stirrup) — vibrate to amplify and transmit that sound to your inner ear. Then the cochlea converts it into nerve impulses and sends them to your brain.

What is otosclerosis?

Otosclerosis is a problem that causes hearing loss when abnormal bone remodeling or growth makes the stapes bone gradually scar and harden. “Oto” is a term for things relating to the ear, and “sclerosis” means an abnormal hardening.

“Instead of vibrating with sound, the bone is stuck firm and partially blocks the transmission of sound down into the cochlea,” explains Dr. Matthew Lowell Kircher, an otolaryngologist with Loyola Medicine in Maywood, Illinois.

Otosclerosis differs from typical age-related sensorineural hearing loss, which is caused by damage to the inner ear. Otosclerosis a form of conductive hearing loss, meaning that sound can’t reach the inner ear. This condition is more common than you might think, affecting more than 3 million Americans.

Otosclerosis causes

Otosclerosis is related to abnormal bone remodeling and middle ear bone growth. Often the cause can’t be found, but risk factors that may be involved include:

Genetics: If you have otosclerosis, there’s a good chance at least one of your relatives does, too. More than half of people with this condition have it in their family tree.

Sex: About twice as many women than men have otosclerosis — especially those of European or Indian descent. Sex hormones may be at least partly responsible, but they may also have a positive affect on the condition. Because estrogen can keep ligaments elastic, including the ones that attach to the ear bones, women with otosclerosis seem less likely than men to lose hearing from otosclerosis.

Measles: Studies have detected genetic material from the measles virus in the stapes of people with otosclerosis. The virus may set in motion a series of processes that, along with factors like genes and autoimmunity, lead to the development of otosclerosis. The measles vaccine likely offers protection against this hearing disorder.

Age: Unlike sensorineural hearing loss, which develops later in life, otosclerosis often starts between the 20s and 40s. Because it progresses slowly, you may not notice that you’ve lost hearing for many years.

Other risk factors include:

Inflammation
Autoimmunity
Viral infections
Hormones

Otosclerosis symptoms

Gradually worsening hearing loss is the main symptom, but it doesn’t present in the same way age-related hearing loss does.

“With sensorineural hearing loss, people often describe a clarity issue,” says Dr. Maura Cosetti, professor of otolaryngology and director of the Ear Institute of Mount Sinai in New York City.

If you have otosclerosis, it can feel like one ear is full or blocked. Usually, the hearing loss starts in one ear. Over time, the other ear also becomes affected.

While sensorineural hearing loss first affects high-frequency sounds, like a bird chirping or the “s” sound in speech, otosclerosis makes it harder to hear low-frequency sounds, like a deep voice, a whisper or the rumble of thunder.

Other symptoms include:

Dizziness or vertigo
Balance problems
Tinnitus: a ringing or buzzing sound in the affected ear

How doctors diagnose otosclerosis

To determine whether you have otosclerosis, you’ll need to see a provider who specializes in hearing loss, such as an otolaryngologist (ear, nose and throat specialist, or ENT) or audiologist.

The diagnostic process starts with an examination of your ear. Your doctor will use a lighted tool called an otoscope to see inside your ear. If you have otosclerosis, this exam won’t reveal any other obvious problems — no impacted wax buildup or fluid, for example. It’s mainly to rule out other conditions that cause hearing loss.

A hearing test is a more definitive way to diagnose this condition.

Audiometry checks your ability to hear sounds of different frequencies and intensities (loudness). Normal hearing is in the range of 20-25 decibels or less. Anything higher could signal otosclerosis.

Tympanometry changes the air pressure inside your ear to detect problems in your middle ear. This test is usually normal in people with otosclerosis, unless the condition is severe.

Sometimes doctors order a CT scan, which takes detailed images inside the ear. This imaging test can show abnormalities in the stapes and other anatomical issues that could be causing your hearing loss.

Otosclerosis treatment options

When hearing loss becomes a problem, you have two main treatment options. One is to wear hearing aids, which amplify the sound coming into your ears. An audiologist will fit your hearing aids to you and adjust them to your degree of hearing loss.

“Increasing the volume is quite effective and can literally bypass the problem,“ Cosetti says.

Stapedectomy or stapedotomy surgery is the other option. For more severe hearing loss, “surgery will typically provide better sound than a hearing aid,“ Kircher says.

The goal of the surgery is to remove all or part of the fixed stapes bone and replace it with prosthetic bones made from titanium. Your ear should heal from surgery in about four to six weeks. It can take a few weeks or months for hearing to improve.

A stapedectomy is usually an outpatient procedure performed while you’re under anesthesia, which means you’ll go home the same day. But there are still possible risks, including:

Dizziness
Tinnitus
Loss of taste, or a metallic taste in the mouth
Weakness in the face
Eardrum perforation

These problems usually go away on their own within a few weeks or months.

A small percentage of very advanced cases of otosclerosis involves the cochlea, leading to severe sensorineural hearing loss. This is treatable with a cochlear implant, which consists of a sound processor that fits behind your ear, attached to a receiver placed under the skin behind the ear. The implant directly sends sound signals to the cochlear nerve in the brain, bypassing the damaged part of the ear.

What’s the outlook?

Otosclerosis is a progressive condition. Without treatment, it will gradually get worse over many years. But treatment is very effective at stopping otosclerosis and restoring hearing.

Stapes surgery improves hearing in around 90 percent or more of people who have it. About 8 percent of those who undergo this surgery won’t have any improvement in hearing, and up to 2 percent will lose hearing.

Your ENT will keep track of your progress after surgery. “We often encourage people to get a hearing test every year or every couple of years,“ Cosetti says.

Bottom line

While there’s no cure for otosclerosis, hearing aids and surgery can be very effective at restoring lost hearing. The earlier you get treated, the better your outcome. See an ENT or audiologist if you have symptoms like hearing loss, tinnitus or a feeling of fullness in your ear. The doctor can do a hearing test and exam to confirm whether you have otosclerosis or another condition and then treat it.

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Stephanie Watson is a freelance writer with more than two decades of experience covering consumer health. Her work has appeared in WebMD, Time, Harvard Health Publications, Healthline, HealthCentral and many other publications. She also served as executive editor of Harvard Women’s Health Watch.