Otosclerosis
Otosclerosis is a condition that affects the tiny bones in the middle ear, called the ossicles. These bones transmit sound vibrations from the eardrum to the inner ear (cochlea), which is our organ of hearing.
Otosclerosis can affect one or both ears. It usually starts in early adulthood, often between the ages of 20 and 40, but it can develop earlier. Typically, it develops very slowly, over months or years.
What causes otosclerosis?
Otosclerosis is caused when abnormal bone growth causes one of the ossicles (the stapes) to become stuck. This stops the stapes from moving freely.
As a result, the ossicles aren’t able to pass sound waves into the inner ear as well as before, causing hearing loss. Eventually, over time, the stapes may become so stuck it can’t move at all – this can cause severe hearing loss.
The exact cause isn’t fully understood. Bone is constantly being broken down and rebuilt in our bodies, but in otosclerosis this process is disrupted and abnormal bone forms around the stapes. Risk factors include:
- Genetics – someone is more likely to get otosclerosis if others in their family have it
- Hormonal changes – some women notice worsening during pregnancy or menopause. This may be why twice as many women as men are affected
- Other possible links – such as the measles virus, though this is still unclear
Symptoms
The main symptom is hearing loss that tends to get worse over time. Other symptoms include:
- Difficulty hearing low-pitched sounds
- Tinnitus (ringing, buzzing or hissing in the ears)
- Rarely, vertigo (spinning dizziness)
Diagnosis
If you notice hearing loss or tinnitus, see your GP. They may refer you to a hearing specialist for tests that are quick and painless. Often, imaging such as a CT (computerised tomography) scan, is needed to confirm the diagnosis.
Treatment options
Hearing aids can be very helpful if you have hearing loss caused by otosclerosis, even though they don’t affect how the condition itself progresses. Hearing aids are often the first option for treatment, they help to improve the hearing loss caused by otosclerosis.
Your doctor may also discuss the option of having an operation called a stapedectomy. This is where a surgeon replaces the stapes with an artificial bone made from metal or plastic. The aim of replacing this bone is to help sound waves travel through to the inner ear. This operation has a good success rate, but it does have risks that your surgeon will discuss with you.
If amplification is still required following surgery, bone-anchored-hearing-systems/hearing-aids (BCHS or BAHA) may be explored if you are not managing well with hearing aids.