Otosclerosis is a bone disease that affects the middle and inner ear. Abnormal bone growth develops around the stapes bone (the innermost bone of the middle ear) in the ear and causes hearing loss. Most people that have otosclerosis start to lose their hearing between the ages of 10 and 30, according to the American Hearing Research Foundation (AHRF). Women are more likely than men to be affected by the disease.
People with otosclerosis may have two different types of hearing loss: conductive and sensory. Conductive hearing loss occurs when the bone growth fixes the stapes bone in one place. The immobility of the stapes prevents the inner ear from picking up sound vibrations. Conductive hearing loss can be treated in many cases.
Sensory hearing loss is the result of impaired or abnormal sensory nerves in the ear. It does not respond as well to treatment as conductive losses.
Causes of Otosclerosis
The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) explains that the cause of otosclerosis is largely genetic — about 60 percent of otosclerosis patients have a family member who also suffers from the condition. (AAO-HNS) Otosclerosis is passed down to a child through at least one parent who carries the gene. However, you may not show symptoms of hearing loss even if you carry the gene for otosclerosis.
Those of Caucasian and Asian descent are more likely to have otosclerosis than other population groups. Women who are pregnant or who have recently given birth are often affected too. Pregnancy does not cause the condition, but can speed up hearing loss caused by the disease. The reason for this phenomenon is not known, but theories point to the hormonal changes that occur during gestation, according to the National Institute on Deafness and Other Communication Disorders. (NIDCD)
The NIDCD also suggests that the measles virus could play a role in otosclerosis, but scientists are not sure why.
Symptoms of Otosclerosis
A gradual loss of hearing is the primary symptom of otosclerosis. Most people lose their ability to hear sounds in the low registers first. Whispers and soft tones are harder to distinguish than louder sounds and higher registers.
As the stapes bone becomes more fixed, your hearing may deteriorate more rapidly. Dizziness, loss of balance, and tinnitus are also symptoms of otosclerosis. Tinnitus is more commonly referred to as “ringing in the ears.” You may experience ringing, buzzing, “whooshing,” roaring, or whistling noises as signs of tinnitus.
Notify your doctor if you encounter any of the symptoms of otosclerosis. Your doctor will most likely refer you to an audiologist who will test your hearing. You may also undergo a computed tomography (CT) scan of your head to look for structural abnormalities in the ears. The CT scan will help determine if your hearing loss is related to otosclerosis or another underlying condition.
The majority of people with otosclerosis experience symptoms in both ears.
Treatment for Otosclerosis
A variety of treatments exist to treat otosclerosis. Your choices depend on the extent of your hearing loss and your personal preferences. Some people opt not to treat the condition.
You may choose to have an annual hearing test to determine your level of loss from one year to the next. Hearing aids can amplify ambient sounds to make communication easier for you. The AHRF points out that hearing aids are more effective for people who have conductive hearing losses. (AHRF) Those with sensory hearing loss do not benefit as much from amplification, because the ear’s nerves are damaged.
Dietary supplements including fluoride and vitamin D may be beneficial to otosclerosis patients, explains the National Institutes of Health. (NIH) These nutrients can slow the hardening of the bone growth within the ear, and can prolong normal hearing in some cases.
Surgery is an option for those with conductive losses too. A surgical procedure called a stapedectomy removes the stapes bone and the abnormal bone growth from the ear. A prosthetic stapes is implanted in the ear. The prosthesis vibrates the same way the original, healthy bone did to produce sound.
Stapedectomy can restore hearing in many people with otosclerosis, but does not treat the dizziness or tinnitus associated with the disease.
Otosclerosis worsens if you do not treat it, and can lead to total deafness in some cases. Stapedectomy is successful in as many as 90 percent of patients, according to the AAO-HNS (AAO-HNS). Those who do not benefit from treatment for otosclerosis may turn their focus to learning to cope with a permanent hearing loss.