Abnormal growth of bone between the middle and inner ear, often leading to hearing loss

  • Symptoms usually develop between the ages of 20 and 30
  • Twice as common in females
  • Often runs in families
  • Lifestyle is not a significant factor

Otosclerosis is a condition in which bone begins to overgrow around the base of the stapes, the innermost of the three tiny bones in the middle ear. The stapes gradually becomes immobilized, preventing the transmission of sound vibrations to the inner ear and causing progressive loss of hearing. Usually both ears are affected, although not always equally. As the disease progresses, nerve damage may occur in the inner ear.

Otosclerosis affects about 1–2 in 100 people in the UK, and symptoms usually first appear between the ages of about 20 and 30. The disorder is twice as common in women as it is in men and may progress more quickly during pregnancy or after starting the contraceptive pill or hormone replacement therapy. In about 6 out of 10 people with otosclerosis, the condition runs in the family and is due to an inherited abnormal gene. In other cases, the underlying cause is unknown.

What are the symptoms?

The symptoms of otosclerosis develop gradually and may include:

  • Hearing loss in which sounds are muffled but may appear to be clearer if there is background noise.

  • Ringing or buzzing noises in the ears (see Tinnitus).

In severe cases, dizziness and imbalance (see Vertigo) may also develop.

What might be done?

Your doctor will probably be able to diagnose otosclerosis from hearing tests and your family history.

If your hearing loss is mild, you may decide to wait until it becomes problematic before opting for treatment, which is either using a hearing aid or surgery to replace the stapes (see Stapedotomy). Hearing aids are often very effective for moderate hearing loss but tend to be less effective when hearing loss is severe. Stapedotomy is usually successful in restoring hearing, but it carries the slight risk of further impairing hearing in the ear operated on. For this reason, it is usually recommended only when hearing loss is severe.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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