by Rachel Waits

Hearing serves a very important function in our lives. Much of thetime, it is taken for granted. We tend not to appreciate it, until itstarts to fail. There are many disorders that can cause a difficultyin hearing and hearing loss. One such disorder is otosclerosis. Thisdisorder deserves a significant amount of research. Not only becausewe are dependent on our sense of hearing, but because its effects arefar reaching. So much so, that it is hard to comprehend how we couldever live without it. It has even been said that Beethoven hadotosclerosis. Toward the end of his career, he could not even hearhis own music (Goldstein, 1999). Its effects are devastating and arewell worth studying.

Otosclerosis is a middle-ear disorder. The hearing loss is usuallyconductive, affecting the bones in the middle ear that conduct soundto the inner ear. This conductive hearing loss is caused by thegrowth of a spongy bone-like tissue that prevents the ossicles (bonesof the middle ear) from moving well. One of the first signs is asmall growth of the tissue in the middle ear. This is often in frontof the oval window, which separates the middle ear from the innerear. This can begin in early childhood or adolescence. The tissue maygrow rapidly and become hard. The bone tissue grows over the stapesossicle attaching it to the oval window. At first, hearing lossoccurs 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 oftendevelops it as well (Otosclerosis, 1998).

There are different categories of otosclerosis."Subclinical Otosclerosis" occurs whenthe tissue does not interfere with the ossicles. A person may havethis form for many years and not know it. Another category is"Clinical Otosclerosis." This type canbe present in the teen years, but not detected until the young adultyears. It is rare for it to occur after the age of fifty. The lastcategory of"Histologic Otosclerosis"occurs when the tissue is present, but it may or may not causehearing loss. "Cochlear Otosclerosis"has been used to refer to sensorineural hearing loss. This is causedby abnormal blood flow to the middle ear, rather than growth oftissue (Otosclerosis, 1998).

Otosclerosis is the most frequent cause of middle ear hearingloss. This disorder affects about ten percent of the United Statespopulation. It is most commonly seen in more women than men (Neeley,1998). A woman may find that it gets worse during pregnancy, whichmay be due to hormones. Also, Caucasians are more likely to have thisdisorder than any other race. Only one percent of African Americanshave otosclerosis. It is also rare among Orientals and NativeAmericans (Otosclerosis, 1998).

Otosclerosis can have a devastating effect on people. Many times,people with this disorder become aware of their hearing loss onlywhen it is brought to their attention by relatives and friends. Thisis attributed to the slow perception of the hearing loss. Someindividuals even learn to read lips to compensate for their hearingloss. Most of the time, they are unaware that they are doing it. Theeffects on daily communication are significant. People withotosclerosis may realize that they ask others to repeat themselvesfrequently. They may also notice a difficulty in hearing whenpeople's faces are turned away (Levinson, 1999). This hearing losscan effect relationships with family and friends. It becomesfrustrating to both the sufferer and their loved ones. The simple actof communication becomes a challenging task. Otosclerosis can alsoeffect job performance. Hearing is almost a necessity for mostoccupations. The situation can even become dangerous if a person withotosclerosis works around construction or other hazardous areas. Theymay not hear warning sounds if they are at risk for injury. Also,simply being able to enjoy the sounds of everyday life are destroyedby this disorder. Otosclerosis can cause physical, emotional, andpsychological distress. There is a great need for research in thisarea to decrease the negative effects it has on its sufferers.

There is a lack of research information concerning the causes ofotosclerosis. The most widely accepted theory is that it is ahereditary disease caused by genetics.In many cases, otosclerosis runs in families, but the genetic part isstill unclear. The most common explanation is that there is adominant gene that may cause otosclerosis. A dominant gene is onethat can cause the disorder. This occurs even if the other gene inthe pair is a "hearing gene." Naturally, it would be easy to assumethat the child of a person with otosclerosis would have a fiftypercent chance of receiving the gene. However, this is not the case.The otosclerosis gene appears to have "reduced penetrance." Thismeans that the abnormal gene does not always dominate over the normalgene. In other words, someone may have a fifty percent chance ofinheriting the gene, but their chance of developing otosclerosis isreduced to twenty to forty percent. On average, a person who has oneparent with otosclerosis has a twenty-five percent chance of beingaffected. If both parents have the disorder, the chance goes up tofifty percent. Many people with otosclerosis, in the same family,usually recognize that it develops at approximately the same age andprogresses at about the same rate (Otosclerosis, 1998). A team ofresearchers attempted to gain a better understanding of the geneticsof otosclerosis and try to detect its heterogeneity. Otoscleroticfamilies were chosen to participate in an analysis. Characteristicssuch as the age of onset and it manifestation were observed. It wasconcluded that heredity is important when considering thesimilarities within the families concerning the development andprogression of otosclerosis. However, even though heredity plays animportant role, a significant amount of cases can arise due the nongenetic causes. Non genetic causes are currently unknown (Sabitha,Ramalingam, Ramalingam, Sivakumaran, & Ramash, 1997).

Even though the cause of otosclerosis is unclear, theinterventions are numerous. There is no known cure for otosclerosis,but different options are available in order to make the disorderbearable. Studies suggest that fluoridein our drinking water may reduce the incidence and severity ofotosclerosis. Fluoride enhances the mineralization of bone. It isbelieved to convert the poorly calcified, active form of otosclerosisto the calcified, inactive form. Oral fluoride supplementation mayslow or halt the disorder from progressing (Tell Me About"Otosclerosis", 1999). One investigation assessed the prevalence ofotosclerosis where the fluoride content in the drinking water waslow. Otosclerotic subjects who participated in the study were givenquestionnaires about their residential history. Those consuming poorfluoridated tap water did not prevent the development ofotosclerosis. It was concluded that there must be a daily fluorideintake of more than three milligrams to reduce the severity of thedisorder (Vartiainen & Vartiainen, 1997).

Studies also suggest that mumps and measlesvaccines may reduce the incidence of otosclerosis. Particlesof viruses have been found in the inner-ear bone of those affected bythe disorder (Tell Me About "Otosclerosis", 1999). Niedermeyer,Arnold, Neubert, and Hofler (1994) used a very sensitive polymearsechain reaction technique in assessing the association between virusesand otosclerosis. Evidence showed that the disorder was a measlesvirus associated disease. It was concluded that the viral infectionacts as at least one factor in the development of the spongytissue.

Hearing aids are also beneficial tothose who suffer with otosclerosis. Hearing aids are recommended forthose who have a significant hearing loss in one ear. Mostindividuals with otosclerosis purchase a hearing aid because of age,failing health, or concerns involving surgery. Hearing aids can alsobe helpful in cases when surgery is not even recommended or when therisks of surgery are too great (Levenson, 1999). Research shows thatanother treatment option is offered to people who suffer fromotosclerosis. This is the bone-anchored hearing aid or BAHA. It iscommonly used for those who have either congenital conductiveproblems or chronic hearing loss. Some patients with otosclerosishave been fitted with the BAHA and gained great benefits compared totheir previous hearing aids. The benefits are mostly related tocosmetic and comfort improvements. Benefits are not necessarily animprovement in hearing ability. This option is beneficial to thosewho cannot undergo surgery and have difficulty with regular hearingaids (Burrell, Cooper, and Proops, 1996).

Surgery is recommended for most whosuffer from a significant hearing loss in either one or both ears.This surgery is called stapedectomy. Itinvolves the removal of the stapes bone. A small window is made tothe inner ear after the stapes bone is removed. The non-functioningstapes bone is replaced with an artificial apparatus made of teflonand platinum (Levenson, 1999). Research shows that the generaloutcome of patients who have undergone surgery for otosclerosis isgreatly rewarding. Patients show a mean improvement of twenty-sixdecibels. They are generally very pleased with surgery. Both patientsand surgeons agree that hearing improvement is an indicator ofsuccess in surgery (Ramsay, Karkkainen, & Palva, 1997). One studymeasured the surgical outcome of 109 patients. The treatment wassuccessful in 86, partially successful in 21, and unsuccessful in 8.The statistics are very promising for those who with to undergo asuccessful surgery (Edussuriya, 1995). Even though surgery comeshighly recommended, there are risks and complications. Dizzinessusually occurs for a few hours after a stapedectomy has beenperformed. This can result in nausea and vomiting. Some unsteadinessis common for the first days after surgery. Dizziness may persist forseveral weeks, but this is rarely the case. Taste disturbances anddry mouth are not uncommon for a few weeks following surgery. In onepercent of patients, additional hearing loss may occur. This is dueto complications in the healing stages. Eardrum perforation can alsooccur during surgery. This can also be due to infection and is anunusual complication. When this happens, the eardrum usually heals ina short period of time. Facial weakness is a very rare and temporaryoccurrence. This is usually due to the swelling of the facial nerveduring the phase of healing. Even though there are associated riskswith surgery, patients still opt highly for this method of correction(Tell Me About "Otosclerosis", 1999).

Most current research on otosclerosis is centered aroundinterventions. It is concerned with correcting the problem of hearingloss to improve upon the sufferer's current state. This is consideredan important topic of study, but other areas need to be investigatedas well. Additional information needs to come from what causesotosclerosis. Yes, it may be genetic, but identifying the gene orgenes that causes otosclerosis may also help in identifying theprocess that is responsible for the disease and developing ways toprevent it. There is a need to focus on prevention and not justintervention. In some cases, after surgical treatment is undergoneand the bone is removed, the spongy tissue grows back. The wholeprocess 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 andadditional research.



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Sabitha, R., Ramalingam, R., Ramalingam, K. K., Sivakumaran, T.A., & Ramash, A. (1997). Genetics of otosclerosis. Journal ofLaryngol Otolaryngology, 111 (2), 109-112.

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Vartianinen, E. & Vartiainen, T. (1997). Effect of drinkingwater fluoridation on the prevalence of otosclerosis. Journal ofLaryngol Otolaryngology, 111 (1), 20-22.