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Last updated: May 3, 2021

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Otosclerosis refers to abnormal bone growth of the bony labyrinth, primarily at the oval window. It manifests at the stapes, which becomes increasingly fixated to the oval window. This process leads to progressive conductive hearing loss because the ossicle's ability to vibrate becomes increasingly limited. Frequently, the other ear is also affected. Left untreated, the disease can progress to deafness. Audiometry reveals decreased air conduction and a characteristic Carhart's notch in the bone conduction curve. Replacement of the upper part of the stapes with a prosthesis (stapedotomy) is the treatment of choice.

  • Sex: > (2:1)
  • Age of onset: 20–40 years
  • Ethnicity: primarily affects whites


Epidemiological data refers to the US, unless otherwise specified.



  • Slowly progressive conductive hearing loss with the 2nd ear affected in ∼ 70% of patients as the disease progresses
  • Tinnitus
  • Mild vertigo (approx. 25%) [1]
  • Paracusis willisii: patients hear better in noisy rather than quiet surroundings.
  • Quiet speech
  • Schwartze sign: a red-blue hue seen through tympanic membrane

Symptoms may increase during pregnancy or following menopause because of hormonal changes.


  • The progression of otosclerosis cannot be significantly influenced by conservative therapy.
  • Surgical procedures
    • The stapes is partly (stapedotomy; ) or completely (stapedectomy) replaced by a prosthesis.
    • Cochlear implant: in the case of bilateral deafness
  1. Dhingra PL, Dhingra S. Diseases of Ear, Nose and Throat. Elsevier ; 2014
  2. Why Does the Carhart Notch appear at 2000Hz?. http://www.audiologyonline.com/ask-the-experts/why-does-carhart-notch-appear-509. Updated: May 9, 2005. Accessed: February 15, 2017.
  3. Kumar V, Abbas AK, Aster JC. Robbins & Cotran Pathologic Basis of Disease. Elsevier Saunders ; 2015