Otosclerosis accounts for roughly 5 to 10 per cent of all hearing loss cases in Australia. An estimated 0.3 to 0.4 per cent of the Australian population, approximately 80,000 to 110,000 people, live with the condition. Despite those numbers, many Australians with otosclerosis go undiagnosed for years. The hearing loss develops so gradually that most people adapt without realising a specific medical condition is responsible. Understanding otosclerosis symptoms and treatment options is the first step toward reclaiming clear hearing.
What Is Otosclerosis
Otosclerosis is a disorder of bone remodelling in the middle ear. The human ear contains three tiny bones called ossicles: the malleus, incus, and stapes. These bones form a chain that transmits sound vibrations from the eardrum to the fluid-filled cochlea in the inner ear. In a healthy ear, the stapes rocks back and forth inside the oval window, a membrane-covered opening to the inner ear, with every sound wave.
In otosclerosis, abnormal spongy bone tissue grows around the base of the stapes. Over time, this new bone hardens and fuses the stapes to the surrounding bone of the skull. The stapes can no longer move freely. Sound vibrations are blocked at the point where they should enter the inner ear, producing what clinicians call a conductive hearing loss. The inner ear and hearing nerve remain functional, but the mechanical pathway that delivers sound to them is obstructed.
The condition can affect one ear or both ears. Roughly 70 per cent of patients develop bilateral otosclerosis, though the severity may differ between ears. In approximately 10 to 15 per cent of cases, the abnormal bone growth extends into the cochlea itself, causing an additional sensorineural component to the hearing loss. This mixed hearing loss pattern is called cochlear otosclerosis and carries different treatment considerations.
Who Gets Otosclerosis
Otosclerosis follows well-documented demographic patterns that help clinicians identify at-risk patients. The condition has a strong genetic component. Between 50 and 60 per cent of people with otosclerosis have a family history of the condition. If one parent has otosclerosis, a child has roughly a 25 per cent chance of developing it. When both parents are affected, that probability rises to approximately 50 per cent.
Age of Onset
Otosclerosis symptoms typically begin between the ages of 15 and 45, with the peak onset occurring in the twenties and thirties. It is uncommon for the condition to begin in childhood or after age 50. Because the hearing loss develops during prime working and family-building years, the functional impact can be significant. Many patients report that their hearing difficulty became noticeable during university, early career stages, or around the time they had young children at home.
Gender
Women are affected roughly twice as often as men. The reason for this gender disparity is not fully understood, but oestrogen and other sex hormones are believed to influence the bone remodelling process. Many women report that their otosclerosis hearing loss first became apparent or worsened during pregnancy, lending support to the hormonal connection. A study published in JAMA Otolaryngology found that up to 30 per cent of women with otosclerosis experienced noticeable hearing deterioration during or shortly after pregnancy.
Genetic and Ethnic Factors
The genetic basis of otosclerosis is polygenic, meaning multiple genes contribute to susceptibility. Several chromosomal loci have been identified through family studies, though no single gene accounts for all cases. White populations of European descent have the highest prevalence. The condition is significantly less common in people of Asian, African, and Indigenous Australian descent. Measles infection has also been proposed as a possible environmental trigger, with some research showing a decline in otosclerosis incidence following widespread measles vaccination programmes.
Otosclerosis Symptoms and Progression
The hallmark symptom of otosclerosis is gradually worsening hearing loss, typically noticed first in one ear. Because the onset is slow, many people cannot pinpoint exactly when their hearing began to decline. Over months to years, the other ear often becomes affected as well. Several characteristic symptoms distinguish otosclerosis from other forms of hearing loss.
Paracusis Willisii
One of the most distinctive otosclerosis symptoms is called paracusis Willisii, also known as the paradox of hearing better in noisy environments. People with otosclerosis often report that they can hear conversations more clearly in a busy restaurant or at a party than in a quiet room. The explanation is that background noise prompts speakers to raise their voices, which pushes sound intensity above the threshold blocked by the fixed stapes. This symptom is so characteristic that experienced audiologists frequently suspect otosclerosis based on this report alone.
Tinnitus
Tinnitus, the perception of ringing, buzzing, or hissing sounds without an external source, affects approximately 50 to 75 per cent of people with otosclerosis. The tinnitus is typically low-pitched and may be constant or intermittent. In most cases, the tinnitus severity corresponds to the degree of hearing loss. Successful treatment of the otosclerosis often reduces or eliminates the tinnitus.
Vertigo and Balance Issues
Dizziness and mild vertigo occur in a minority of otosclerosis patients, estimated at roughly 20 to 25 per cent. These symptoms are more common when cochlear otosclerosis is present, as the abnormal bone growth interferes with the balance organs located in the inner ear. The dizziness is usually intermittent and mild rather than the severe spinning vertigo associated with conditions like Meniere disease.
Disease Progression
Without treatment, otosclerosis hearing loss typically progresses over 10 to 15 years from mild to moderate or severe. The rate of progression varies considerably between individuals. Some people experience rapid worsening over a few years, while others maintain relatively stable hearing for decades. The condition generally stabilises after the fifth decade of life. In cochlear otosclerosis, the sensorineural component may continue to worsen even after middle age, which is one reason why early evaluation matters.
How Otosclerosis Is Diagnosed
Diagnosing otosclerosis requires a combination of clinical history, physical examination, and specialised audiometric testing. The diagnostic process typically begins when a patient presents with progressive hearing loss and their clinician identifies features consistent with a conductive pathology.
Audiometry
A comprehensive audiogram is the foundation of otosclerosis diagnosis. The audiogram measures hearing thresholds across the frequency range, typically 250 Hz to 8000 Hz. In otosclerosis, the audiogram characteristically shows an air-bone gap: bone conduction thresholds (which bypass the middle ear and test inner ear function directly) are near normal, while air conduction thresholds (which test the full hearing pathway) are elevated, indicating that sound is not being transmitted efficiently through the middle ear. Early in the disease, this gap is most apparent at lower frequencies. As the stapes becomes more firmly fixed, the gap widens across all frequencies.
A specific audiometric pattern called the Carhart notch is considered a signature of otosclerosis. This pattern shows a characteristic dip in bone conduction thresholds at 2000 Hz, producing a notch shape on the audiogram. While not present in every case, the Carhart notch is a strong diagnostic indicator when it appears. A comprehensive hearing test that includes both air and bone conduction measurements is essential for identifying these patterns.
Tympanometry
Tympanometry measures how the eardrum moves in response to changes in air pressure. In otosclerosis, the tympanogram is typically Type A (normal pressure with normal eardrum mobility) because the eardrum itself is healthy and the middle ear space is aerated. However, acoustic reflex testing, which is performed alongside tympanometry, reveals absent or abnormal reflexes on the affected side. When the stapes is fixed, the stapedius muscle cannot contract normally in response to loud sounds, so the reflex is absent. This finding, combined with a normal tympanogram and an air-bone gap on the audiogram, creates a triad strongly suggestive of otosclerosis.
Imaging
High-resolution computed tomography (HRCT) of the temporal bone can visualise the abnormal bone growth around the oval window and confirm the diagnosis in cases where audiometric findings are ambiguous. CT imaging is particularly useful when cochlear otosclerosis is suspected, as it can show the extent of bone involvement in the cochlea. However, CT is not always necessary when clinical and audiometric findings are classic. Magnetic resonance imaging (MRI) may be used to rule out other conditions, such as acoustic neuroma, that can mimic otosclerosis symptoms.
Otosclerosis Treatment Options
Treatment for otosclerosis ranges from monitoring to surgical intervention, depending on the severity of hearing loss, the patient's age and health status, and personal preferences. There is no medication that cures otosclerosis or reverses the abnormal bone growth. However, several effective treatment options exist.
Watchful Waiting
When otosclerosis hearing loss is mild and not significantly affecting daily communication, a watchful waiting approach may be appropriate. This involves regular hearing monitoring, typically every six to twelve months, to track progression. Annual audiometry allows the audiologist to detect changes in the air-bone gap and identify when intervention becomes necessary. Watchful waiting is most often recommended for patients with early-stage disease, those with unilateral involvement and normal hearing in the unaffected ear, or those who prefer to defer treatment.
Hearing Aids
Hearing aids are an effective non-surgical option for otosclerosis. Because the inner ear remains functional in most cases, amplifying incoming sound compensates for the conductive blockage at the stapes. Modern hearing aids can be precisely programmed to match the degree and configuration of the conductive loss. For patients with bilateral otosclerosis, binaural hearing aids restore balanced hearing. Hearing aids are particularly suitable for patients who are not surgical candidates due to medical conditions, those with cochlear otosclerosis where surgery carries higher risk, or those who prefer to avoid surgery.
It is worth noting that hearing aids do not address the underlying disease process. If otosclerosis continues to progress, hearing aid settings will need to be adjusted accordingly. However, for many patients, hearing aids provide excellent long-term functional improvement without the risks associated with surgery.
Stapedectomy Surgery
Stapedectomy is the surgical treatment for otosclerosis and has been performed since the 1950s with steadily improving outcomes. The procedure involves removing the fixed stapes bone (or part of it) and replacing it with a tiny prosthetic device called a piston or stapes prosthesis. This prosthesis reconnects the ossicular chain, allowing sound vibrations to pass from the incus through the prosthesis to the oval window and into the inner ear fluid.
The surgery is typically performed under local or general anaesthesia as a day procedure. The surgeon accesses the middle ear through the ear canal, lifts the eardrum, and works under a microscope. The procedure takes roughly 60 to 90 minutes. Most patients return home the same day.
Outcomes for stapedectomy are among the best in otological surgery. Published studies report hearing improvement in 90 to 95 per cent of cases, with many patients achieving hearing thresholds within 10 to 20 decibels of normal. The degree of improvement depends on factors including the severity of preoperative hearing loss, the skill and experience of the surgeon, and whether cochlear involvement is present.
As with any surgical procedure, stapedectomy carries risks. Total hearing loss in the operated ear occurs in approximately 1 to 2 per cent of cases. Other potential complications include dizziness, altered taste (due to manipulation of the chorda tympani nerve), tinnitus changes, and facial nerve weakness. These risks are relatively low in the hands of an experienced otologist, and most patients find that the probability of significant hearing improvement far outweighs the risks.
Fluoride Therapy
Sodium fluoride supplementation has been studied as a medical treatment for otosclerosis, based on the theory that fluoride promotes recalcification of the spongy otosclerotic bone and slows disease progression. Evidence for fluoride therapy remains limited and mixed. Some clinical studies have reported modest stabilisation of hearing loss, while others found no significant benefit compared with placebo. Fluoride therapy is not commonly prescribed in current Australian clinical practice but may be considered in specific cases of aggressive or rapidly progressive cochlear otosclerosis.
Living with Otosclerosis
A diagnosis of otosclerosis does not mean you have to accept poor hearing as inevitable. With appropriate treatment, most people with otosclerosis achieve functional hearing that allows full participation in work, social life, and daily activities. The key is early evaluation and informed decision-making about treatment options.
For patients who choose surgery, the rehabilitation period is relatively short. Most people notice hearing improvement within the first two to four weeks after stapedectomy, though full stabilisation may take several months. During the early recovery period, activities that increase pressure in the ear (such as flying, heavy lifting, and nose blowing) are restricted to protect the surgical site.
For patients who opt for hearing aids, working with an experienced audiologist ensures the devices are programmed to address the specific conductive loss pattern of otosclerosis. Ongoing monitoring allows adjustments as the condition evolves. If you are based in Victoria, our Melbourne audiologists provide both diagnostic assessment and hearing aid management for otosclerosis patients.
Frequently Asked Questions
Can otosclerosis be cured?
Otosclerosis cannot be cured, but it can be effectively managed. Stapedectomy surgery restores hearing in approximately 90 to 95 per cent of patients by replacing the fixed stapes bone with a prosthesis. Hearing aids are a non-surgical alternative that improve sound amplification. The condition typically stabilises after middle age, and most people who receive treatment regain functional hearing.
How do I know if I have otosclerosis?
Otosclerosis typically presents as gradually worsening hearing loss in one or both ears, often beginning between ages 15 and 45. Many people notice that they hear better in noisy environments, a pattern called paracusis Willisii. Tinnitus is also common. A comprehensive hearing test including audiometry and tympanometry can identify the characteristic patterns of otosclerosis, and an ENT specialist can confirm the diagnosis.
Is stapedectomy surgery safe?
Stapedectomy is considered a safe and well-established surgical procedure with a high success rate. Approximately 90 to 95 per cent of patients experience significant hearing improvement. As with any surgery, risks exist, including a small chance (around 1 to 2 per cent) of total hearing loss in the operated ear, dizziness, altered taste, and facial nerve weakness. An ENT surgeon will discuss the risks and benefits specific to your case before proceeding.
Does otosclerosis get worse during pregnancy?
Yes, otosclerosis often progresses more rapidly during pregnancy due to hormonal changes that affect bone remodelling. Many women first notice otosclerosis symptoms or experience worsening hearing during or shortly after pregnancy. If you have a family history of otosclerosis and notice hearing changes during pregnancy, a hearing assessment is recommended.
Works Cited
Menger, David J., and Robert J. P. van den Berge. "Otosclerosis: Clinical Presentation and Management." BMJ Clinical Evidence, 2015, Art. No. 0507.
Chole, Richard A., and George A. Gates. "Otosclerosis." Cummings Otolaryngology Head and Neck Surgery, 7th ed., Elsevier, 2020, pp. 2154-2168.
Grayeli, Alexandre B., et al. "Prognostic Factors in Stapes Surgery." JAMA Otolaryngology Head and Neck Surgery, vol. 146, no. 1, 2020, pp. 34-40.
Marx, Marcus, et al. "Otosclerosis and Stapes Surgery: A Systematic Review." Otolaryngology Clinics of North America, vol. 53, no. 5, 2020, pp. 753-773.
Australian Institute of Health and Welfare. "Ear and Hearing Health." AIHW, Australian Government, 2024, aihw.gov.au/reports/australias-health/hearing-health.
Vrabec, Joseph T., and C. Gary Jackson. "Surgical Management of Otosclerosis." Otolaryngologic Clinics of North America, vol. 51, no. 2, 2018, pp. 397-411.