Otosclerosis is a common cause of hearing impairment. (The word otosclerosis can be broken into its two medical words: “oto” for ear, and “sclerosis” meaning hardening.) Approximately 5% of all people with hearing impairment have otosclerosis. The condition is hereditary. That is, members of a family pass the condition down to their children. Although otosclerosis is hereditary, this does not necessarily mean that the children of patients with otosclerosis will develop the condition.
Hearing Impairment from Otosclerosis
Otosclerosis is an abnormal growth of bone. The abnormal bone growth of otosclerosis may spread to the inner ear, stapes (the third ear bone), or to both of these areas.
When otosclerosis spreads to the inner ear a sensorineural hearing impairment (see How We Hear) may result due to interference with hearing nerve function. Once nerve impairment develops it is permanent. Very rarely does otosclerosis alone cause total deafness. In selected cases medications may be prescribed in an attempt to prevent further nerve impairment.
It is more common for otosclerosis to surround the stapes bone than to damage the inner ear. The abnormal otosclerotic bone hardens around the stapes and eventually stops the movement of the stapes. The immobile stapes cannot carry sound vibrations to the inner ear. Therefore a conductive hearing loss develops.
The degree of sensorineural and/or conductive hearing impairment can be determined only by careful hearing tests.
There is no local treatment to the ear itself or any medication that will improve the hearing in persons with otosclerosis. In some cases, medication may prevent further nerve hearing loss.
A medication known as Florical (8.3mg sodium fluoride and 364mg of calcium carbonate) is sometimes prescribed to prevent further nerve hearing loss. This medication slows down the growth and may eventually stop the growth of otosclerosis.
The optimal dosage of Florical is 1 capsule every 12 hours with meals. Ideally, this medication should be taken for two years. After two years, the hearing level, the degree of tinnitus, and the severity of imbalance are reevaluated. If these conditions have stabilized, the Florical may be discontinued or the dosage reduced. Florical should be avoided during pregnancy.
The stapes operation (stapedectomy) is recommended for patients with otosclerosis who are candidates for surgery. This operation is performed under local or general anesthesia with the use of laser and microscopic techniques. Most patients go home the same day (outpatient procedure). Convalescence at home for about a week or so is recommended. Nearly 90% of these operations are successful in improving the conductive hearing loss.