In this article, we will explain what otosclerosis is, outline its common causes and symptoms, and discuss how it is diagnosed and treated. We will also cover some frequently asked questions relating to otosclerosis.
What is Otosclerosis?
Normally, the stapes vibrates to transmit sound waves into the inner ear. When it is unable to move, sound cannot travel effectively into the inner ear, leading to conductive hearing loss. It is also possible to have cochlear otosclerosis, where spongy bone develops within the cochlear, thereby damaging the inner ear structures and causing sensorineural hearing loss.
The degree of hearing loss can range from mild to severe, although total deafness is rare, and usually both ears are affected, with one ear more affected than the other.
The exact cause of otosclerosis is still not fully understood. However, several contributing factors may play a role:
- Previous measles infection
- Stress fractures in the bony tissue surrounding the inner ear
- Immune system disorders
- An imbalance in cytokine levels that may trigger abnormal bone growth around the stapes
- Family history of otosclerosis, suggesting a hereditary component
Am I At Risk For Otosclerosis?
- Family history: Having close relatives with otosclerosis significantly increases the risk of one developing otosclerosis, suggesting a genetic link.
- Gender: Females are more likely to develop otosclerosis than males.
- Ethnicity: The condition is more common among Caucasians compared to other ethnicities.
- Pregnancy: Hormonal changes during pregnancy may accelerate the progression of otosclerosis or trigger its onset in individuals already predisposed.
- Osteogenesis imperfecta: People with this inherited disorder, also known as brittle bone disease, are at higher risk of developing otosclerosis.
- Environmental factors: Certain viral infections, such as measles, have been linked to the development or worsening of otosclerosis.
What are the Common Signs and Symptoms of Otosclerosis?
How is Otosclerosis Diagnosed?
Medical history
- Family history of otosclerosis
- History of ear infections
- Previous measles infection
- Autoimmune disorders
- Hormonal changes, including pregnancy
- Head trauma or other medical conditions that could affect hearing
Physical examination
- Earwax impaction in the ear canal
- Infection of the ear canal
- Inflammation within the ear
- Structural abnormalities of the ear canal or eardrum
Otosclerosis itself cannot be directly seen through an otoscope, but this step is important to rule out alternative conditions.
Hearing tests
Image caption: Otosclerosis audiogram, with the Carhart notch at 2kHz
- Pure tone audiometry: This measures the softest sounds you can hear at different pitches and can reveal patterns that suggest stiffening of the middle-ear bones. In individuals with otosclerosis, the audiogram often reflects conductive hearing loss, along with a key feature called the Carhart notch at around 2000 Hz (refer to the audiogram above).
- Tympanometry: In this test, the movement of the eardrum is measured to assess the integrity of the eardrum and middle ear structures.
Imaging tests
Final diagnosis
What are the Management Options for Otosclerosis?
Stapedectomy
If both ears are affected by otosclerosis, surgery is usually performed on one ear at a time, with at least six months of healing before the second procedure. While stapedectomy can restore significant hearing, some hearing loss may remain, and in rare cases, hearing may worsen after surgery. Stapedectomy is also unable to prevent or stop any future development of otosclerosis.
Hearing devices
An audiologist can adjust and customise the settings to match your specific hearing profile, ensuring effectiveness and comfort for your daily listening needs. While hearing devices improve hearing ability, they do not stop the progression of otosclerosis.
Cochlear implantsย
The progression of cochlear otosclerosis has to be monitored closely to keep the option of cochlear implant viable. If the cochlea is severely or fully ossified, the insertion of the implant would be challenging or deemed impossible.
FAQs About Otosclerosis
How fast does otosclerosis progress?
Why is there the Carhart notch in otosclerosis?
The Carhart notch is most prominent around the 2000 Hz frequency and is caused by reduced movement of the ossicles in bone conduction, especially the stapes, rather than true inner ear damage. After successful stapes surgery, this notch often disappears.
Can I prevent otosclerosis?
What happens if otosclerosis is untreated?
It is important to consult a healthcare provider or hearing care professional for recommendations on whether to monitor the condition or consider management options such as hearing aids or surgery.