What Are the Causes of Middle Ear Bone Thickening?

The middle ear has three bones called the incus, malleus and stapes. Sound causes the vibration of each bone as it touches the next one in formation and relays it to the inner ear. When it reaches the inner ear, the sound has increased seven times greater then it was originally. The ear bones are the smallest bones in the body. Thickening of these bones can cause them not to vibrate, which results in otosclerosis.

Causes

• Research has failed to provide any concrete cause for otosclerosis. It is believed to be hereditary and may be the result of a faulty gene. A chance of contracting the disease through one parent is 25 percent. If both parents have the condition it doubles the risk. The condition is the main cause of deafness among young adults.

  Ten percent of the United States population is affected. Otosclerosis affects Caucasians and people of Asian decent more than other races. Women tend to have the disease more than men. The possibility of hormonal changes during pregnancy may trigger the disease. According to the National Institute on Deafness and Other Communication Disorders the evidence suggests that viral infections such as measles can cause the disease.

  The American Hearing Research Foundation reported in 2002 that an autoimmune connection was found in a family that suffered from the condition. A mutation was present in a gene for collagen.

Hearing Loss

• Otosclerosis progresses slowly and can result in total deafness since it affects both ears. The slow progression may cause some people to delay treatment, not realizing that hearing loss is gradually taking place. The bones in the middle ear become more hardened, loosing flexibility and causing the bone vibrations to become weak and ineffective.

  Hearing loss can begin as early as age 15 but can occur as late as age 45. Dizziness or an unbalanced feeling can occur. Tinnitus, a ringing in the ear, is present in about 75 percent of people with otosclerosis.

Diagnosis and Treatment

• A hearing test can reveal how much hearing loss has occurred, but there are different causes of hearing loss. A microscopic exam of the middle and inner ear in a hospital setting may be necessary to determine the actual cause.

  If the condition has not progressed to the cochlear that is located next to the three middle ear bones, a portable hearing aid can restore some hearing function. In some cases a stapedectomy may be necessary to restore hearing loss. It involves removing the stapes and replacing it with a prosthesis.