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Acoustic neuroma is a benign tumor that grows on the auditory nerve near the point where it enters the labyrinth of the inner ear. The tumor causes gradual and progressive loss of auditory and vestibular nerve functions on one side. Eventually the tumor grows out into the brain cavity, causing headaches and paralysis. If it is not removed, blindness and death may result. Fortunately, acoustic neuroma usually can be diagnosed early by magnetic resonance imaging (MRI) and removed before it has serious consequences.
(Lucente 151) Mnire’s disease, also called endolymphatic hydrops, is a fairly common disorder of the labyrinth of the inner ear that affects both the vestibular nerve, with resultant attacks of vertigo, and the auditory nerve, with impairment of hearing. It was first described in 1861 by a French physician, Prosper Mnire. It is now known that the symptoms are caused by an excess of endolymphatic fluid in the inner ear. The diagnosis is made from the recurring attacks of vertigo, often with nausea and vomiting, impairment of hearing with a distortion of sound in the affected ear that fluctuates in degree, and a sense of fullness or pressure in the ear. The cause of the excess of endolymphatic fluid is not always known, although in many cases it results from defective functioning of the endolymphatic duct and sac, the structures that normally reabsorb endolymphatic fluid from the inner ear.
Allergic reactions to certain foods may also cause the disease. The treatment of Mnire’s disease is directed toward finding the cause of the excess of endolymphatic fluid in order to control it. If medical treatment does not relieve the repeated attacks of vertigo, surgery may be necessary. (Lucente 150-151) Presbycusis is the gradual decline of hearing function that results from aging.
It is similar to other aging processes because it occurs at different ages and at different rates among the population. As a person ages, there is a gradual loss of cochlear hair cells, resulting in gradually reduced and eventually lost hearing. Hearing is reduced at the highest audible frequencies (around 20,000 hertz) and then progressively for sounds of lower frequencies. Usually the slow diminishing of hearing does not begin until after age 60. The affected individual notices increasing difficulty in hearing sounds of high pitch and in understanding conversation.
Correction of a nutritional deficiency of zinc, coenzyme Q10, or possibly vitamin A may stabilize the progressive hearing loss. The physician must make certain that the individual does not have a correctable impairment, such as accumulated earwax, secretory otitis media, or stirrup fixation by otosclerosis, as part of the difficulty. An electrical hearing aid is of limited help to some, while others find that a hearing aid makes voices louder but less clear and therefore is of little help.(Lucente 464-465) The child born deaf or with a severe hearing impairment cannot acquire speech by the normal process but must attend special classes or a school for the deaf to be taught speech and lip-reading. Most of these children have remnants of the sense of hearing that can be utilized in their schooling by the use of aids to amplify sound. The child with a moderate or mild hearing impairment is able to acquire speech independently but a little more slowly than the child with normal hearing, while speech-correction instruction is usually required to improve diction.
Cochlear implants can be considered for children and adults with a total absence of hearing or hearing loss so profound that hearing aids are not helpful. Implants make it possible for a deaf child to develop speech and allow a deaf adult to communicate more effectively. (Www.deaf.com) Advances in hearing-aid technology have served to increase the proportion of hearing-impaired individuals who can benefit substantially from amplification. Selection of an appropriate hearing aid for individuals with sensorineural (or nerve-type) hearing loss may be difficult and time-consuming. Research has demonstrated repeatedly, however, that the ability of listeners with sensorineural hearing loss to understand speech at conversational levels often can be enhanced significantly by use of an appropriate hearing aid. For those individuals whose hearing loss causes severe distortion of speech, use of a hearing aid in combination with lip-reading may increase the amount of speech the individual can understand through lip-reading alone.
On the other hand, selection of a hearing aid is often a simpler matter for listeners with hearing loss of the conductive type. Careful selection is necessary to ensure that maximum understanding of speech is obtainable in noisy environments. The hearing-impaired individual should consult with trained professionals such as audiologists, who are trained in evaluating the benefit derived from the use of a hearing aid. Lip-reading, which actually entails attentive observation of the entire facial expression rather than the movements of the lips alone, is used even by persons with normal hearing who, in the presence of background noise, need these visual clues to supplement hearing.
As hearing begins to be impaired, lip-reading, which might better be termed speech reading, becomes increasingly valuable and important. The hearing-impaired individual who knows a spoken language can learn lip-reading by careful observation of a speaker of that language. Formal instruction in lip-reading by a teacher individually or in classes is necessary for those hearing-impaired persons who have not acquired knowledge of a spoken language. The greater the loss of hearing, the more essential lip-reading becomes, for which good lighting is essential.
The hearing-impaired may also be taught a sign language, such as American Sign Language, as a communications tool. Speech-correction instruction, needed for the young with serious degrees of impaired hearing, also becomes necessary for the adult who suddenly loses all hearing in both ears. Without the monitoring effect of hearing one’s own voice, speech begins to deteriorate and to acquire the flat, toneless quality of the profoundly deaf. Deafness was once thought of a disease that would leave the individual as a recluse because of their lacking the ability to communicate with society. Medicine has made great amounts of progress in diagnosing and treating hearing disorders, while other have helped to improve the quality of life for the deaf today through deaf culture.
Bibliography Books Lucente, Frank. Essentials of Otolaryngology. New York: Raven Press, 1997. Turkington, Carol.
The Encyclopedia of Deafness and Hearing Disorders. New York: Fact on File, 1992. Internet National Association for the Deaf www.nad.org Deaf.com www.deaf.com www.deafworldweb.com Infomedical Dictionary http://home.ipoline.com/~guoli/med/puto.htm.
