Overview

Otosclerosis is a common form of adult-onset hearing impairment.¹ It occurs when there is irregular bone remodelling/growth in the middle of the ear. In rare cases, it can occur in the inner ear. It can happen to any individual but it is more prevalent in white individuals who are assigned female at birth (AFAB) between the ages of 20 and 45. 

The condition is typically diagnosed through a number of steps. Firstly, a GP will assess the patient experiencing symptoms. Some of the symptoms include gradual hearing loss and worsening or constant tinnitus. Then they will refer the patient to an audiologist for hearing tests and/or an ear, nose, and throat (ENT) specialist to look at the ear. A computer tomography (CT) scan may be ordered. Once diagnosed there are various treatment options depending on the severity of the condition and location of irregular bone growth. These include hearing aids, cochlear implants or a stapedectomy. 

Early diagnosis and treatment of otosclerosis is essential, as it can improve an individual's hearing and quality of life. In this article, we will explore how otosclerosis is diagnosed and the currently available treatment options. 

What is otosclerosis?

Otosclerosis is a condition where a tiny bone (called the stapes) inside the ear fuses with other parts of the ear. When this occurs it can stop you from being able to hear properly. This happens in the middle ear or, in rare cases, the inner ear. The bone remodelling changes the structure of the ear and interferes with sound’s ability to travel through the ear. Currently, there is no known cause of otosclerosis but it is believed that it could be passed on in families. This is because individuals who have a close relative with otosclerosis are more likely to get it. 

The hearing loss caused by otosclerosis is gradual and rarely causes total hearing loss.  Symptoms of otosclerosis include:

• Dizziness 
• Balance problems 
• Vertigo
• Gradual hearing loss in either one or both ears, typically happening over several years
• Experiencing tinnitus (hearing ringing, buzzing, or other noises) in either one or both ears 

It is advised to see a GP if your hearing is gradually getting worse, or if you are experiencing regular/constant tinnitus, worsening tinnitus or tinnitus that is affecting daily life. This could be that it is impacting sleep, concentration, mood, or causing you to feel anxious or depressed. 

Diagnosis

When individuals are experiencing symptoms such as gradual worsening of hearing, and tinnitus affecting daily life, they should book an appointment with their GP. At this appointment, a GP will check inside their ears and typically refer them to another specialist. This could be an audiologist, who will perform hearing tests, and/or an ENT specialist. 

An ENT specialist may also look inside the individual's ears and possibly arrange a CT scan. This scan can provide a detailed image of the bones and tissues inside the ear. By looking at the ear, an ENT specialist will rule out other conditions that may share similar symptoms. 

There are various hearing tests that can look at the extent of hearing loss. One example is an audiogram. Audiograms measure your hearing across a range of frequencies. Another is a tympanogram which informs the audiologist how well the individual’s eardrum is working. 

With these tests, healthcare providers can gain insight into an individual's hearing levels and have a look at whether there has been bone growth/ remodelling. This information can aid in the diagnosis of otosclerosis. 

Treatment

The treatment of otosclerosis depends on the severity of the condition (the extent of hearing loss) and the location of the irregular bone growth/remodelling. Hearing loss caused by otosclerosis is managed by many individuals using hearing aids. In some cases, a stapedectomy can be recommended to improve hearing. Individuals with otosclerosis in the inner ear (known as cochlear otosclerosis) may be recommended a cochlear implant to improve hearing. 

Hearing aids

Hearing aids are used to improve hearing but do not prevent the worsening of otosclerosis. Hearing aids work by amplifying surrounding sound which means individuals can hear better. They can be customised by an audiologist to ensure they accommodate the individual’s needs. Hearing aids may be a preferential treatment in mild cases of otosclerosis.

Stapedectomy

Stapedectomy is an operation offered to individuals with otosclerosis. In this procedure, a prosthesis (replacement hearing bone) is placed in the middle ear. This prosthesis bypasses the stapes bone. This allows sound waves to travel to your inner ear and so improves hearing. When both ears are affected by otosclerosis the operation for each ear will be done at separate times, allowing time for healing. 

Research has found that stapedectomy procedures can significantly improve speech recognition in patients with far-advanced otosclerosis.² Speech recognition is a common type of hearing test. This suggests that a stapedectomy is a beneficial treatment option for individuals with far-advanced otosclerosis. 

A follow-up study 28-30 years after individuals underwent stapedectomy found that many individuals found hearing aids beneficial.³ This suggests that hearing aids may be a helpful option to maintain a good level of hearing in individuals post-stapedectomy. 

Cochlear implants

Cochlear implants are typically used as treatment options for individuals who have otosclerosis in the inner ear. A cochlear implant improves hearing by creating a new pathway for sound to travel to the brain. They turn sounds into electrical signals and send them to the cochlea in the inner ear. This signal then travels to the brain and is heard as a sound. Cochlear implants are considered a relatively safe treatment option and have been found to provide promising outcomes in patients with otosclerosis. There are however many factors that can affect the outcome. These include:⁴

• Cochlear ossification (the process of bone formation)
• Previous operations
• Duration of deafness

Current research on new treatments

Current research focuses on discovering new medical treatments for otosclerosis. These are non-invasive and known as conservative treatments. Conservative treatments of otosclerosis include sodium fluoride, bisphosphonates, and other modern medicines. These medications focus on slowing down the progression of the condition and gradual hearing loss. There have been encouraging results with bisphosphonates, which are reported to stabilise hearing. However, these treatments are yet to be administered.^5,6 

FAQs

At what age do you start to develop otosclerosis?

Otosclerosis can start developing at any age between 10-45 but it most commonly has been found to start when individuals are in their 20s. It is typically adult-onset.

Does otosclerosis affect speech?

It has been observed that individuals with otosclerosis can often speak in a soft manner. This may be because individuals with otosclerosis can perceive their voices as loud. 

Can otosclerosis be cured naturally? 

Currently, there are no known cures for otosclerosis. Treatment and management of the condition are suggested to alleviate the condition. This is done through hearing aids, stapedectomy, and cochlear implants which all work to improve hearing. 

Summary

Otosclerosis is a common form of adult-onset hearing loss. It is a gradual loss of hearing that occurs when a bone in the ear (stapes) fuses with another bone and stops sound from being able to travel through the ear. Symptoms can affect daily life and individuals with consistent symptoms should see a GP. A GP will assess the ear and often refer the individual to an audiologist and/or ENT specialist. They may undergo certain steps to aid diagnosis. These include hearing tests, assessing the ear, and CT scans. Hearing tests assess the extent of the hearing loss. Ear assessments and scans can provide insight into bone remodelling and growth. 

Once diagnosed there are various treatment options depending on the circumstances. These are typically hearing aids, stapedectomy, and cochlear implants. Hearing aids improve hearing by amplifying sounds. A stapedectomy is a procedure in which a prosthesis is placed to bypass the stape which allows sound to travel in the ear. Cochlear implants turn sound into electrical signals in the cochlea which are then sent to the brain and turned into sound. There is currently research being done on non-invasive treatment of otosclerosis using sodium fluoride, bisphosphonates, and other medicines. Results so far are promising but these treatments are yet to be administered.