Hearing serves a very important function in our lives. Much of the time, it is taken for granted. We tend not to appreciate it, until it starts to fail. There are many disorders that can cause a difficulty in hearing and hearing loss. One such disorder is otosclerosis. This disorder deserves a significant amount of research. Not only because we are dependent on our sense of hearing, but because its effects are far reaching. So much so, that it is hard to comprehend how we could ever live without it. It has even been said that Beethoven had otosclerosis. Toward the end of his career, he could not even hear his own music (Goldstein, 1999). Its effects are devastating and are well worth studying.
Otosclerosis is a middle-ear disorder. The hearing loss is usually conductive, affecting the bones in the middle ear that conduct sound to the inner ear. This conductive hearing loss is caused by the growth of a spongy bone-like tissue that prevents the ossicles (bones of the middle ear) from moving well. One of the first signs is a small growth of the tissue in the middle ear. This is often in front of the oval window, which separates the middle ear from the inner ear. This can begin in early childhood or adolescence. The tissue may grow rapidly and become hard. The bone tissue grows over the stapes ossicle attaching it to the oval window. At first, hearing loss occurs in the low frequencies. High frequencies are affected next, followed by the loss of hearing in the middle frequencies. Otosclerosis usually begins in one ear, but the other ear often develops it as well (Otosclerosis, 1998).
There are different categories of otosclerosis. "Subclinical Otosclerosis" occurs when the tissue does not interfere with the ossicles. A person may have this form for many years and not know it. Another category is "Clinical Otosclerosis." This type can be present in the teen years, but not detected until the young adult years. It is rare for it to occur after the age of fifty. The last category of"Histologic Otosclerosis" occurs when the tissue is present, but it may or may not cause hearing loss. "Cochlear Otosclerosis" has been used to refer to sensorineural hearing loss. This is caused by abnormal blood flow to the middle ear, rather than growth of tissue (Otosclerosis, 1998).
Otosclerosis is the most frequent cause of middle ear hearing loss. This disorder affects about ten percent of the United States population. It is most commonly seen in more women than men (Neeley, 1998). A woman may find that it gets worse during pregnancy, which may be due to hormones. Also, Caucasians are more likely to have this disorder than any other race. Only one percent of African Americans have otosclerosis. It is also rare among Orientals and Native Americans (Otosclerosis, 1998).
Otosclerosis can have a devastating effect on people. Many times, people with this disorder become aware of their hearing loss only when it is brought to their attention by relatives and friends. This is attributed to the slow perception of the hearing loss. Some individuals even learn to read lips to compensate for their hearing loss. Most of the time, they are unaware that they are doing it. The effects on daily communication are significant. People with otosclerosis may realize that they ask others to repeat themselves frequently. They may also notice a difficulty in hearing when people's faces are turned away (Levinson, 1999). This hearing loss can effect relationships with family and friends. It becomes frustrating to both the sufferer and their loved ones. The simple act of communication becomes a challenging task. Otosclerosis can also effect job performance. Hearing is almost a necessity for most occupations. The situation can even become dangerous if a person with otosclerosis works around construction or other hazardous areas. They may not hear warning sounds if they are at risk for injury. Also, simply being able to enjoy the sounds of everyday life are destroyed by this disorder. Otosclerosis can cause physical, emotional, and psychological distress. There is a great need for research in this area to decrease the negative effects it has on its sufferers.
There is a lack of research information concerning the causes of otosclerosis. The most widely accepted theory is that it is a hereditary disease caused by genetics. In many cases, otosclerosis runs in families, but the genetic part is still unclear. The most common explanation is that there is a dominant gene that may cause otosclerosis. A dominant gene is one that can cause the disorder. This occurs even if the other gene in the pair is a "hearing gene." Naturally, it would be easy to assume that the child of a person with otosclerosis would have a fifty percent chance of receiving the gene. However, this is not the case. The otosclerosis gene appears to have "reduced penetrance." This means that the abnormal gene does not always dominate over the normal gene. In other words, someone may have a fifty percent chance of inheriting the gene, but their chance of developing otosclerosis is reduced to twenty to forty percent. On average, a person who has one parent with otosclerosis has a twenty-five percent chance of being affected. If both parents have the disorder, the chance goes up to fifty percent. Many people with otosclerosis, in the same family, usually recognize that it develops at approximately the same age and progresses at about the same rate (Otosclerosis, 1998). A team of researchers attempted to gain a better understanding of the genetics of otosclerosis and try to detect its heterogeneity. Otosclerotic families were chosen to participate in an analysis. Characteristics such as the age of onset and it manifestation were observed. It was concluded that heredity is important when considering the similarities within the families concerning the development and progression of otosclerosis. However, even though heredity plays an important role, a significant amount of cases can arise due the non genetic causes. Non genetic causes are currently unknown (Sabitha, Ramalingam, Ramalingam, Sivakumaran, & Ramash, 1997).
Even though the cause of otosclerosis is unclear, the interventions are numerous. There is no known cure for otosclerosis, but different options are available in order to make the disorder bearable. Studies suggest that fluoride in our drinking water may reduce the incidence and severity of otosclerosis. Fluoride enhances the mineralization of bone. It is believed to convert the poorly calcified, active form of otosclerosis to the calcified, inactive form. Oral fluoride supplementation may slow or halt the disorder from progressing (Tell Me About "Otosclerosis", 1999). One investigation assessed the prevalence of otosclerosis where the fluoride content in the drinking water was low. Otosclerotic subjects who participated in the study were given questionnaires about their residential history. Those consuming poor fluoridated tap water did not prevent the development of otosclerosis. It was concluded that there must be a daily fluoride intake of more than three milligrams to reduce the severity of the disorder (Vartiainen & Vartiainen, 1997).
Studies also suggest that mumps and measles vaccines may reduce the incidence of otosclerosis. Particles of viruses have been found in the inner-ear bone of those affected by the disorder (Tell Me About "Otosclerosis", 1999). Niedermeyer, Arnold, Neubert, and Hofler (1994) used a very sensitive polymearse chain reaction technique in assessing the association between viruses and otosclerosis. Evidence showed that the disorder was a measles virus associated disease. It was concluded that the viral infection acts as at least one factor in the development of the spongy tissue.
Hearing aids are also beneficial to those who suffer with otosclerosis. Hearing aids are recommended for those who have a significant hearing loss in one ear. Most individuals with otosclerosis purchase a hearing aid because of age, failing health, or concerns involving surgery. Hearing aids can also be helpful in cases when surgery is not even recommended or when the risks of surgery are too great (Levenson, 1999). Research shows that another treatment option is offered to people who suffer from otosclerosis. This is the bone-anchored hearing aid or BAHA. It is commonly used for those who have either congenital conductive problems or chronic hearing loss. Some patients with otosclerosis have been fitted with the BAHA and gained great benefits compared to their previous hearing aids. The benefits are mostly related to cosmetic and comfort improvements. Benefits are not necessarily an improvement in hearing ability. This option is beneficial to those who cannot undergo surgery and have difficulty with regular hearing aids (Burrell, Cooper, and Proops, 1996).
Surgery is recommended for most who suffer from a significant hearing loss in either one or both ears. This surgery is called stapedectomy. It involves the removal of the stapes bone. A small window is made to the inner ear after the stapes bone is removed. The non-functioning stapes bone is replaced with an artificial apparatus made of teflon and platinum (Levenson, 1999). Research shows that the general outcome of patients who have undergone surgery for otosclerosis is greatly rewarding. Patients show a mean improvement of twenty-six decibels. They are generally very pleased with surgery. Both patients and surgeons agree that hearing improvement is an indicator of success in surgery (Ramsay, Karkkainen, & Palva, 1997). One study measured the surgical outcome of 109 patients. The treatment was successful in 86, partially successful in 21, and unsuccessful in 8. The statistics are very promising for those who with to undergo a successful surgery (Edussuriya, 1995). Even though surgery comes highly recommended, there are risks and complications. Dizziness usually occurs for a few hours after a stapedectomy has been performed. This can result in nausea and vomiting. Some unsteadiness is common for the first days after surgery. Dizziness may persist for several weeks, but this is rarely the case. Taste disturbances and dry mouth are not uncommon for a few weeks following surgery. In one percent of patients, additional hearing loss may occur. This is due to complications in the healing stages. Eardrum perforation can also occur during surgery. This can also be due to infection and is an unusual complication. When this happens, the eardrum usually heals in a short period of time. Facial weakness is a very rare and temporary occurrence. This is usually due to the swelling of the facial nerve during the phase of healing. Even though there are associated risks with surgery, patients still opt highly for this method of correction (Tell Me About "Otosclerosis", 1999).
Most current research on otosclerosis is centered around interventions. It is concerned with correcting the problem of hearing loss to improve upon the sufferer's current state. This is considered an important topic of study, but other areas need to be investigated as well. Additional information needs to come from what causes otosclerosis. Yes, it may be genetic, but identifying the gene or genes that causes otosclerosis may also help in identifying the process that is responsible for the disease and developing ways to prevent it. There is a need to focus on prevention and not just intervention. In some cases, after surgical treatment is undergone and the bone is removed, the spongy tissue grows back. The whole process is repeated. These cases deserve special consideration too. Researchers need to study methods to prevent this from happening. Otosclerosis is a unique disorder that requires special attention and additional research.
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