Otosclerosis (otospongiosis) - a focal lesion of an osteal capsule of a labyrinth of an obscure etiology. Progressing depression of hearing is consequence of bracing by the center of a underfoot plate of a stapes in an oval window. In some cases pathological growth of a bone extends on the channel of a cochlea. Disease arises usually during puberty or the nearest years after it. Sometimes meets at children's age (8-10 years). Women are ill more often, than men.

Signs, current. A progressing bradyacuasia (it is usual on both of an ear), coming more often for no apparent reason, a sonitus. Quite often sonitus - the basic complaint of patients, and in a noisy situation of the patient hears better, illness, as a rule, develops slowly. Pregnancy and labors usually accelerate current of process.