Otosclerosis

What is this condition?

The most common cause of conductive deafness, otosclerosis is the slow formation of spongy bone in the inner ear. It occurs more often in whites and is two times more common in females than in males. Onset usually occurs between ages 15 and 50. With surgery, the prognosis is good.

What causes it?

Otosclerosis appears to result from genetic factors. Many people report a family history of hearing loss. Pregnancy may trigger onset of this condition.

What are its symptoms?

This disorder causes progressive hearing loss in one ear, which may advance to deafness in both ears. Other symptoms include ringing in the ears and hearing conversation better in a noisy environment than in a quiet one.

How is it diagnosed?

Early diagnosis is based on a Rinne test that shows bone conduction lasting longer than air conduction (normally, the reverse is true). As otosclerosis progresses, bone conduction also deteriorates. Audiometric testing reveals hearing loss ranging from 60 decibels in early stages to total loss. The Weber test detects sound lateralizing to the more affected ear. Physical exam reveals a normal eardrum.

How is it treated?

The doctor will perform a stapedectomy (removal of the stapes, one of the small bones of the middle ear that contributes to the transmission of sound) and insert a prosthesis to restore partial or total hearing. This procedure is performed on one ear at a time, starting with the ear that has suffered greater damage. Alternative surgery includes stapedotomy (creation of a small hole in the stapes' footplate). through which a wire and piston are inserted.

After surgery, the person is hospitalized for 2 or 3 days and receives antibiotics to prevent infection.

If surgery isn't possible, a hearing aid (air conduction aid with molded ear insert receiver) enables the person to hear conversation in normal surroundings, although this therapy isn't as effective as stapedectomy.