otosclerosis

A disease of the otic capsule (bony labyrinth) characterized by formation of soft, vascular bone and resulting in progressive conductive hearing loss because of fixation of the stapes and sensory hearing loss because of involvement of the cochlear duct. [oto- + G. sklerosis, hardening]

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oto·scle·ro·sis .ōt-ō-sklə-'rō-səs n, pl -ro·ses -.sēz growth of spongy bone in the inner ear where it gradually obstructs the oval window or round window or both and causes progressively increasing deafness

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n.

a disorder causing deafness in adult life. An overgrowth of the bone of the inner ear leads to the third ear ossicle (the stapes) becoming fixed to the fenestra ovalis, which separates the middle and inner ears, so that sounds cannot be conducted to the inner ear. deafness is progressive and may become very severe, but treatment by surgery is highly effective (see fenestration, stapedectomy). Nonsurgical treatments include fluoride tablets and the provision of suitable hearing aid.

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oto·scle·ro·sis (o″to-sklə-roґsis) [oto- + sclerosis] otospongiosis of the bony labyrinth, especially adjacent to the footplate of the stapes; it may cause bony ankylosis of the stapes, resulting in conductive hearing loss. Cochlear otosclerosis may also develop, resulting in sensorineural hearing loss. otosclerotic adj