Most commonly, a conductive pattern of hearing loss appears. The conductive type of otosclerosis usually progresses during young adult years. Dizziness and imbalance is a feature of otosclerosis in roughly 25 percent of cases. In about half of all patients, there is a family history of similar problems. Women are affected twice as often as men.
Otosclerosis often progresses more rapidly during pregnancy.
Otosclerosis is often discovered during or just after pregnancy. Usually both ears are affected, although in about 10 to 15 percent of patients, hearing loss occurs only on one side. Otosclerosis is an inherited, autosomal dominant disease with variable penetrance. Some believe that chronic measles infection in bone predisposes patients to otosclerosis. Pathologically, otosclerosis occurs only in human temporal bones and is considered to be a disorder of new bone formation.