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CHAPTER 18: HEAD, NECK, AND SENSORY CONCERNS

Overview

Symptoms

    Hearing Difficulty

    Vision Problems

    Dry Mouth

    Difficulty Chewing

    Oral and Dental Problems

Conditions

    Thyroid Disease


Overview

Sensory concerns such as hearing difficulty and vision problems produce a large proportion of the increased impairment we may experience as we age. In fact, the top causes of disability among older people are joint, bone, and muscle problems and sensory impairments. This chapter addresses head, neck, and sensory concerns.

SYMPTOMS Hearing Difficulty

Hearing loss is the most common sensory impairment experienced by older people. Approximately 30 percent of people over the age of 65 report problems with their hearing. This impairment becomes increasingly common with advanced age, rising to about 50 percent in 85-year-old people. Among people in nursing homes, the prevalence of hearing impairment approaches 60 percent. In all older age groups, impaired hearing and deafness are more common in men than in women; almost 20 percent of very old men have significant hearing loss in both ears. Approximately two million elderly people use hearing aids, but about 20 percent of these people report that they still have difficulty hearing. People with Alzheimer's disease have a higher rate of hearing loss than other people of the same age. Hearing loss is also associated with poorer cognitive function in people without dementia.

How Normal Hearing Works

Normal hearing depends upon the functioning of three systems: the ear, the central auditory system in the brain that controls hearing, and processes in the brain that are not strictly limited to auditory signals (see Figure 26). The ear modifies the sense of sound, while the brain's activities help us perceive and interpret sound.

    Sound is quantified by frequency (pitch) measured in cycles per second, and by intensity (loudness) measured in decibels (see Figure 27). In young people, the frequency range of normal hearing runs from 30 cycles per second to about 20,000 cycles per second. In older people, the range is from 250 to 8,000 cycles per second. Normal speech occurs within a frequency range of 500 to 2,000 cycles per second. The intensity at which a sound must be generated to be heard by a person is termed that person's threshold; the higher the threshold the poorer the hearing.

Common Causes of Hearing Loss

While hearing impairment is not a universal aspect of aging, it is exceptionally common. Hearing loss in elderly people usually fits a characteristic pattern that is called presbycusis. Presbycusis is a gradual, progressive, high-frequency hearing loss that affects both ears equally.

    Even if the hearing loss is very mild, a person may still have difficulty understanding speech. Studies of otherwise normal older people indicate that up to half of them may have difficulty understanding speech on formal testing. A problem within the brain in processing sounds is believed to be responsible. Changes in memory and overall slowing of mental processes may also affect speech understanding and hearing.

    Some specific changes in the ear and brain are associated with hearing loss, including atrophy of the sensory part of the ear, loss of sensory cells, and loss of nerves in the central nervous system. The influence of environmental factors such as excess noise has not been clearly defined.

Other Causes of Hearing Loss

In addition to presbycusis, other ear and hearing disorders are classified in three general categories: (1) conductive hearing loss disorders that affect the normal transmission of sound waves from the eardrum to the sensory apparatus; (2) sensory neural hearing loss disorders that are caused by problems of the auditory nerves; and (3) central hearing loss disorders that are due to disturbances in the brain. When hearing loss is due to more than one of these conditions, it is called a mixed hearing loss. Earwax can be a major cause of hearing loss, reducing sound intensity as much as 35 percent. Earwax clogging the ear canal is one important and easily correctable cause of conductive hearing loss found in about a third of older people.

    Most causes of conductive hearing loss are not very common in older people. These include severe ear infections, arthritis affecting the bones of the ear, and trauma. However, Paget's disease of bone, which may affect the ear, is a cause of conductive hearing loss that is of particular importance to older people.

    Sensory hearing loss may be due to M&36;ni&47;re's disease or medications, especially antibiotics and diuretics. Table 24 shows a partial list of drugs that can produce hearing impairment. Sensory hearing loss can also be caused by brain tumors, hemorrhage into the brain, and other diseases. Causes of central hearing loss are extremely rare and involve damage of both hemispheres of the brain.

Table 24. Drugs That Can Cause Hearing Loss

Antibiotics

Cancer chemotherapy

Erythromycin

NSAIDs

Vancomycin

Diuretics

Others

Drugs used to treat malaria

Evaluation of Hearing Loss

The evaluation of hearing loss begins with telling the physician about any difficulties related to hearing. Some individuals may not readily want to volunteer this information or may attribute the difficulty to aging. The person's ears are inspected for earwax, which should be completely removed by the physician before any further testing is performed.

    Pure tone audiometry has emerged as the basic test of hearing. The test can define the extent of hearing impairment and determine the location of the problem. It can also suggest some causes of the hearing difficulty.

    Although the magnitude and pattern of hearing loss can be determined by use of pure tone audiometry, the value of these findings is limited because hearing in social situations rarely depends upon pure tone hearing.

Hearing Aids

Many older people use hearing aids to amplify sound. Some people and their physicians, however, have been led to believe that sensory hearing loss will not benefit from amplification--this is not true. In fact, well-selected hearing aids can improve the efficiency of speech perception even for people with severe sensory neural hearing loss.

    In general, hearing aids should be worn in both ears to preserve the directional clues that help to localize sound. If only one hearing aid is used, however, the condition of the poorer ear will determine which ear is amplified. If the poor ear has internally generated distortion, amplification is likely to make matters worse. Because of this, the person should be tested with the hearing aid applied to the good ear, then the poor ear, and then both ears.

    The most popular hearing aids are the behind-the-ear and in-the-ear models. Behind-the-ear hearing aids have the advantage of being durable, easily repaired, and more easily adjusted. Although the in-the-ear models may be easier to insert in the ear, they may be more difficult to adjust, and they may produce more acoustic feedback. Hearing aids that fit in the ear canal have the advantage to some of being the least visible hearing aids. They also improve hearing at higher frequencies due to better sound transmission.

    Regardless of which type of hearing aid is selected, a person should purchase it from a comprehensive hearing aid center on a 30-day trial basis. These centers provide assessment, service, and rehabilitation. Immediately following the purchase of the hearing aid, the person should begin the aural rehabilitation program. This includes counseling regarding the benefits and limitations of hearing aids and suggestions for communicating with others. Some suggestions for improving communication with hearing impaired people are provided in Table 25.

    A common problem limiting the effectiveness of hearing aids is their lack of use. Less than one-third of people over age 70 with hearing difficulty use the hearing aid for more than eight hours a day. Approximately one-third use hearing aids only for a few hours per week. Reasons people give for not using hearing aids include diminished dexterity, noise (such as the amplification of back-ground noise), and the belief that the aid is not needed. Another problem that limits the use of hearing aids is the cost, which is usually around $500 per hearing aid.

    The hearing mechanism can also be simulated electronically by means of an implanted electrode in the middle ear that stimulates the nerves directly. Unfortunately, the hearing provided by these implants is only rudimentary and their use is restricted to those who are totally deaf, which is rare among elderly people.

    In addition to hearing aids, other helpful assistive listening devices (ALDs) are available. All of these devices rely on a microphone that is moved close to the sound source; the sound is usually clearer with less background noise. Systems differ, however, as to the method of transmitting the sound from the signal source to the ear. Infrared systems, which use nonvisible light waves as the carrier signal, are available as individual systems and cost several thousand dollars. These are principally helpful for home use to amplify home entertainment systems. Infrared technology has also been used for sound systems in public buildings, auditoriums, and churches. More costly than infrared systems, FM broadcasting systems are similar to infrared systems except that they use radio frequencies as the carrier signal.

Table 25. Suggestions for Improving Communication with a Hearing-Impaired Elderly Person

  • Reduce or eliminate background noise. Close doors and turn off TV or running water.
  • Face listener. Keep your face at level of listener's eyes. Maintain eye contact.
  • Allow adequate light to fall on your face.
  • Give listener a clear view of your face. Keep hands or other objects down. Avoid chewing gum. Beards or mustaches should be trimmed so as not to interfere with speech reading.
  • Use facial expressions and gestures to convey meaning.
  • Avoid writing or walking around the room while talking.
  • Gain person's attention before beginning to speak.
  • Speak in normal tone of voice or slightly louder. Shouting does not help because hearing loss is not simply reduction in loudness of sound.
  • Speak clearly, a little more slowly, and in short sentences, using simple words.
  • Have the person repeat the message to be sure it is understood. (Some people do not admit to a handicap.)
  • Repeat or rephrase in a different way.
  • If the person can read, write down key words.
  • If the individual has a hearing aid, learn how to help with it.
  • Learn how to use assistive listening devices.
  • Arrange for the individual to have a vision exam.

Source: Adapted from Voeks SK, Gallagher CM, Langer EH, et al. Hearing loss in the nursing home: an institutional issue. Journal of the American Geriatrics Society. 1990;38:145. Reprinted with permission.

    The telephone company offers several assistive devices for the deaf or hearing impaired. These are usually provided at no additional charge if a physician has certified that the person is hearing impaired. These devices include amplifiers, louder bells, and light signals that flash on and off when the phone rings. Telecommunication Device for the Deaf (TDD) service, which links a typewriter source and a destination over the telephone lines, is also available.

    Nonauditory communication aids, such as closed-captioning television and text messages, and interactive services on the computer are also available to help hearing-impaired people.

Vision Problems

Visual impairment increases with advancing age. Approximately 15 percent of people over the age of 65 report having vision impairment, and this figure rises to nearly 30 percent of those 85 years old and older. More than 90 percent of older people require eyeglasses, and over 20 percent of those over 85 report that even with the aid of glasses they have a great deal of difficulty seeing. Age-related changes in the lens of the eye causes a scattering of light over the retina, which decreases the older person's resistance to glare (see Chapter 2). This can constitute a significant threat to safe driving at night. In addition, there is an almost universal age-associated change in near vision that makes the eye lens more rigid, less flexible, and thus less able to focus at a close range.

    The health consequences of impaired vision can be significant. For example, five-year survival rates decline with progressively worse vision. Hip fractures may be more common in people with impaired vision: The authors of one survey estimated that 18 percent of hip fractures occurred because impaired vision led to tripping, stumbling, missing a step, and falling.

Causes of Visual Impairment

There are four major eye diseases that cause visual impairment in older adults: cataracts, macular degeneration, glaucoma, and diabetic eye disease. The prevalence of cataracts and macular degeneration increases with age. This is less the case with diabetic eye disease and glaucoma. Approximately 13 percent of people between the ages of 65 and 74 have cataracts; this figure rises to over 40 percent in people 75 years and older. For people living in nursing homes, the incidence of cataracts is estimated to be between 60 and 80 percent. Age-related macular degeneration (ARMD) also rises with advancing age, from 6.4 percent in people between the ages of 65 and 74 to almost 20 percent in those over the age of 75. The incidence in nursing homes is estimated to be between 30 and 40 percent. Open-angle glaucoma and diabetic eye disease rates also increase with age, but the prevalence of either disease does not exceed 3.5 percent even in the oldest age group. However, the prevalence of open-angle glaucoma in nursing homes may be considerably higher; it is estimated at approximately 10 percent. There is some evidence that sunlight causes damage in the eyes that relates to the formation of cataracts. In particular, an association between ultraviolet B light and cataracts has been demonstrated in one study.

Cataracts. Cataracts are defined as a clouding or opacity in the lens of the eye (see Figure 28). A variety of changes in the lens have been noted with aging, and some of these are believed to be important in the development of cataracts. For example, the aging lens develops a yellow-brown pigmentation caused by protein in the lens that increases with age.

    Symptoms of cataracts differ in composition and location, but regardless of the type of cataract involved people with cataracts have a painless, progressive loss of vision that may involve either one or both eyes. Early on, the location of the cataract may influence the nature of the vision loss. For example, the ability to see things far away particularly at night and in bright daylight is most severely compromised by one type of cataract while near vision may be affected by another. Months to years later when the cataract is fully developed, the entire range of vision has been impaired. Once the presence of a cataract has been established, people whose vision is poorer than expected on the basis of the cataract alone should have further testing to assess whether there are additional vision problems.

Treatment of Cataracts. As with any vision disorder, the impact of the vision loss upon daily activities must guide the treatment. If the severity of the vision loss does not affect a person's ability to function, nonsurgical management is certainly appropriate, especially when the person does not wish to have surgery, or when other medical or eye problems make surgery too dangerous. Under these circumstances, eyeglasses, contact lenses, and aids for low vision should be used. Specific measures to prevent the progression of cataracts include controlling the blood sugar of people who have diabetes mellitus and protecting the eyes against ultraviolet light with sunglasses.

    Cataract surgery with lens implants improves vision as well as a person's subjective and objective capacity to function. Ophthalmologists are generally very accurate in their predictions of the amount of visual improvement following surgery. Mental function and performance of daily activities also seem to improve.

    The surgical removal of a cataract is accomplished either by removing the entire lens with its enveloping capsule, or by extracapsular extraction, which leaves the transparent back of the lens in place. About 90 percent of cataract extractions are done by this extracapsular method. This method requires a smaller incision and leaves the posterior capsule in place, providing a stabilizing membrane to hold a lens implant and to maintain the natural compartments of the eye.

    A technique that uses sound waves to pulverize the lens and vacuum it out of the eye using special instruments has been devised. The incision for this appears to be even smaller than for usual extracapsular cataract extractions. This technique, however, appears to be less valuable for those people who have very hard cataracts.

    Once the cataract has been removed, the magnifying power of the lenses must be replaced by one of three options: eyeglasses, contact lenses, or lens implants. Although eyeglasses are safe and inexpensive, they are usually less than optimal and people who have had only one eye operated on frequently experience double vision with the glasses. Other common deficiencies of cataract glasses are visual distortions, spatial dislocation, and reduced fields of vision. Contact lenses help correct these optical problems but they may be difficult for very old people to manage, especially because of the manual dexterity that they require. They may also cause corneal ulcers. In contrast, lens implants provide the best result on vision and do not require special care.

    Lens implants can be placed in front of the iris, in the iris plane, or behind the iris (see Figure 28). By far the most common lens implant (used in more than 90 percent of replacements) is that which is placed in the back chamber behind the iris. This capitalizes on the presence of the natural lens capsule to help support the implant. The appropriate power of the lens implant can be determined by special testing before surgery. Most people can have their cataracts removed and the lens implanted as a single procedure done on an outpatient basis. Delayed clouding of the posterior capsule may develop in as many as 50 percent of people over a three-year period after this type of surgery. Fortunately, this complication can be treated nonsurgically using a special laser technique. This treatment results in improved vision in up to 90 percent of affected individuals.

Macular Degeneration. Although the exact cause of macular degeneration is not entirely clear, it is the leading cause of permanent central vision loss in older people. Changes in the pigmented tissues of the retina, or retinal pigmented epithelium (RPE), are related to the development of macular degeneration. This thin layer of cells is vitally important in the metabolic chemistry of vitamin A, in maintaining the blood vessels in the retinal area, in transporting various substances in and out of the eye's light receptor (photoreceptor) cells, and in removing depleted photoreceptors.

    An initial deterioration of the RPE or a disturbance between the RPE and the photoreceptor cells may be the original event leading to macular degeneration. The result of this is the accumulation of material within the RPE and the formation of deposits between the base membrane of the RPE and the remaining membranes. The medical name for these deposits is drusen (from the German, meaning "strong nodule"). Drusen usually appear as hard pinhead-size areas in the retina that are visible to the physician looking into the eye with an ophthalmoscope. Other eye changes in macular degeneration include atrophy of the photoreceptors and the proliferation of new blood vessels. These new vessels may leak or bleed, leading to hemorrhage and possible detachment of the RPE. Blood stimulates the formation of scar tissue.

    Ophthalmologists often classify macular degeneration into dry or wet macular degeneration. The dry form accounts for approximately 80 to 90 percent of macular degeneration and causes loss of central vision. A person with the dry form will see a dark fuzzy spot in the middle of the visual field.

    Generally the vision of only 10 percent of people with dry macular degeneration is impaired to the extent of legal blindness, which is corrected vision of 20/200 or worse in the best eye--20/200 vision means that a person can only see at 20 feet what a normal person can see 200 feet away. Twenty feet is the distance at which the eye relaxes from the work of near vision. It is important to note that people with age-related macular degeneration still retain good peripheral vision despite meeting the criteria for legal blindness.

    No specific medical treatment for dry macular degeneration has gained widespread clinical acceptance, but oral zinc supplementation may be effective in slowing the progression of visual loss. Progressive loss of vision seems less common and less severe in people who are given zinc. An Amsler grid (essentially a piece of graph paper) may help in monitoring people with early macular degeneration. A person can use it on a daily basis to check for changes in vision that may indicate fluid accumulation in the back of the eye and possible retinal detachment. These abnormalities distort the appearance of the grid, making some of the lines seem wavy or curved. Other indications that a problem has developed in a person who has macular degeneration include sudden or recent loss of central vision, blurred vision, visual distortion, or a new blind spot. Medical management of dry macular degeneration also makes use of aids for low vision, which are described below.

    Wet macular degeneration is much more likely to cause very severe visual loss. This condition is present in 80 to 90 percent of eyes with 20/200 vision or worse. Wet macular degeneration is characterized by the formation of new blood vessels with consequent separation of the RPE from the retina. For people under the age of 55 with a pure detachment of the RPE, the prognosis is excellent, but older people have a much higher risk of complications and visual loss. Generally, simple RPE detachment is usually managed without surgery or lasers in elderly people. Treatment with lasers is indicated in people with macular degeneration and new blood vessel growth. This use of laser is best regarded as post-poning rather than preventing severe visual loss in people with this problem. In only a minority of people with wet macular degeneration is this problem confined to the avascular zone, and laser treatments are not of value within the zone. The complications of laser treatment include decreased vision and laser injury to areas adjacent to and beyond the intended area of treatment.

Glaucoma. In glaucoma, vision loss is due to increased fluid pressure within the eye that damages the optic nerve. This affects approximately 3 percent of people over the age of 65. To the examining physician, glaucoma is detectable as increased pressure within the eye, atrophy and cupping of the optic nerve, and defects in the visual field. Approximately 95 percent of people with glaucoma have open-angle glaucoma (OAG). Virtually all of the rest have angle-closure glaucoma.

Causes and Symptoms of Glaucoma. In OAG, the aqueous humor (the fluid that circulates in the chamber between the cornea and the lens) that is formed in the eye travels to the front of the eye and gets reabsorbed. In angle-closure glaucoma, the chamber angle is closed by a bowing of the iris. As the pupil dilates, the iris blocks the flow of aqueous humor out of the eye, which causes the pressure in the eye to rise rapidly and precipitates halos, blurred vision, and eye pain, and is an emergency. Angle-closure glaucoma needs to be treated immediately with special eyedrops to constrict the pupil.

    Treatment of open-angle glaucoma is not usually started simply on the basis of finding a high pressure within the eye, except for when this pressure is extremely high. More commonly, treatment is started only if there is evidence of glaucoma damage to the eye, such as changes in the optic disk or in the optic nerve fibers. Drops that constrict the pupil stimulate the muscles of the eye and open the pores that reabsorb the fluid. Adrenaline eyedrops decrease the pressure within the eye by decreasing the production of aqueous humor and by increasing its removal. Other medications may be prescribed by an ophthalmologist. These other medications, including beta-blockers and carbonic anhydrase inhibitors, must be used carefully in older people because they can produce confusion, drowsiness, poor appetite, numbness in the hands and feet, and can precipitate kidney stones.

    When medical therapy fails to provide adequate control of the pressure, surgery is necessary. Laser treatment can help the flow of aqueous humor and lower the pressure within the eye.

Diabetic Eye Disease. Diabetic eye disease is called diabetic retinopathy, and appears to be more closely related to the length of time the person has had diabetes mellitus than to the age of the person. Nonetheless, approximately 3 percent of people over the age of 85 have this condition. (Diabetes mellitus is discussed on page 436.) The disorder is usually classified as either background retinopathy or proliferative retinopathy. Background retinopathy includes hemorrhages, small blood vessel defects called microaneurysms, and the accumulation of fluid around the macula. Proliferative retinopathy is characterized by new blood vessel formation, bleeding within the eye, and retinal detachment. There is less risk of proliferative retinopathy in older people, but the large number of elderly people who have diabetes mellitus justifies its importance.

    Whether or not tight control of diabetes can prevent diabetic retinopathy remains an unsettled question. Regular eye checkups are a valuable part of care for every person with diabetes.

Other Causes of Blindness. Although much less common, other causes of blindness can occur in older people, such as reduced blood flow to the optic nerve; inflammation involving the arteries of the head; inflammation to the optic nerve; and masses in the brain. Inflammation around the arteries that run along the temples (temporal arteries) is a rare but serious disorder because this inflammation can lead to irreversible blindness.

Other Disorders of the Eye. While they are not directly related to vision loss, several other disorders commonly occur in older people. With aging, increased relaxation of the skin around the eyelids and decreased muscle tone can lead to an in-turning of the eyelid margin toward the cornea (entropion) with subsequent irritation by the eyelashes. Another condition (ectropion) is when the eyelid sags and causes a loss of tears, drying out the tissue at the base of the eye. Both of these conditions can be corrected with simple surgical therapies. A number of underlying diseases, especially those related to rheumatoid arthritis can affect the tear system leading to dry eyes. Replacement of the fluid with artificial tears is the most common treatment for these conditions, but some people become sensitive to the preservatives used in the artificial tears and experience further irritation because of them.

Aids for Low Vision. Providing adequate lighting is one of the keys to improving vision in older people with impaired sight. Precautions must be taken to avoid glare. Because of this, filters, visors, and sunglasses may be valuable. Reading glasses with magnifying lenses can add some lens power and are the most commonly prescribed low-vision aids for older people. Once the simple magnifying glasses move beyond low power, the preservation of binocular vision becomes very difficult. Magnifying glasses usually allow broad fields of vision, but require that objects be held relatively close to the eye. Handheld magnifying glasses, which can be used as either a major or supplemental low-vision aid, can be helpful for simple tasks conducted at about arm's length. Stand magnifiers require an additional reading lens to focus the image, but have the advantage of eliminating the problem of hand unsteadiness. For longer working distances, near vision and distance telescopes provide magnification, but they tend to distort images and create a tunnel vision effect. Video and computer magnifiers may be valuable, but their use is limited by their high cost and lack of portability. Nonvision aids such as talking books may eliminate some of the handicaps that are caused by visual loss.

Dry Mouth

Three major pairs of salivary glands and hundreds of minor salivary glands secrete saliva into the mouth. In general, saliva serves as a primary defense for all oral tissues. It lubricates the soft tissues, helps in remineralizing the teeth, and also helps to control bacterial and fungal populations in the mouth. Because of this, dry mouth caused by lack of salivary secretion can have severe consequences.

Causes of Dry Mouth

In older people, a dry mouth with reduced saliva may be caused by a variety of diseases and treatments. For example, dryness of the mouth is a side effect of over 400 prescription medications. Many antidepressant, antihypertensive, anti-inflammatory, and diuretic medications commonly used by elderly people can reduce salivary gland performance. People taking these medications frequently develop oral dryness and have a very high rate of cavities.

    Sj&41;gren's syndrome (named for the Swedish physician who first described it) is the single most common disease affecting salivary glands. This is an illness that affects the immune system of about a million Americans, the majority of whom are postmenopausal women. The condition diminishes salivary gland function, causing a dry mouth and difficulty in swallowing dry foods such as bread. The person may notice that lipstick sticks to the teeth.

    The management of dry mouth requires a careful examination by a physician or dentist to check the three major pairs of salivary glands and to look for Sj&41;gren's syndrome.

    If the cause of the dry mouth is due to medication, it is important to reduce the medication levels or to replace them with alternative preparations. Sometimes special medications can be used to stimulate saliva production gently if some functioning salivary glands remain. However, no satisfactory salivary substitutes are available for people when the glands cease to function. Artificial saliva can be useful in controlling dental disease, but it has minimal effects on problems with the soft tissue in the mouth. All people with dry mouth should receive comprehensive and frequent preventive dental care, including regular fluoride treatments.

Difficulty Chewing

Among older people, the most common difficult mouth movement is chewing. Older people with an intact set of teeth even show a modest increase in the time they take to chew a mouthful of food before swallowing. In those with poor dentition or those wearing dentures, the time needed is even longer.

Causes of Difficulty Chewing. The causes of difficulty chewing in an older person are jaw pain, limited ability to open the jaw, or a shift in the jawbone as the mouth opens. These problems sometimes result from difficulties in the joint at the base of the jaw (under the ear) and can either be muscular or dental in origin. A form of blood vessel inflammation called temporal arteritis can cause chewing difficulty by reducing blood flow to the masseter, the muscle that allows chewing. A thorough medical and dental evaluation usually uncovers the cause and leads to appropriate treatment.

Oral and Dental Problems

The mouth serves two essential functions: the production of speech and the initial preparation of food for proper digestion. Together these functions require intact teeth, healthy lining of the tissues (mucosa), good sensation, and proper salivary gland function (see Figure 29). If disease affects any of these components, the consequences can be serious. There is no evidence that oral health and function decrease with age. Older people experience more medical problems in general, and it is likely that illness and medications contribute to oral problems. However, in many older people, oral tissues remain healthy.

Dental Disease

Dental disease refers to disease affecting tooth surfaces. It is classified according to which tooth surface has been affected by decay. The most common form of dental disease are the cavities in children and young adults on the chewing surface, or crown, of the tooth. Cavities along the root surface are more prevalent among older people and occur when gums recede to expose the root. Older adults and younger adults have about the same amount of cavities.

Preventing Cavities

Oral hygiene is the major determinant of cavity disease. Adults with untreated cavities have more amounts of plaque, tartar, and inflammation of the gums (gingivitis) than adults without cavities. Because of this, good oral hygiene--care of the teeth and gums--is important for all people regardless of their age to reduce the risk of dental decay. Fluoride treatment is usually given to prevent cavities in children and in certain high-risk groups of adults, such as those who have had radiation treatment to the head or neck. People of all ages who have high amounts of fluoride in their water have significantly fewer cavities compared with lifelong residents of nonfluoridated communities. Fluoride is helpful in older adults, even when fluoride exposure does not begin until late adulthood. Because of this, fluoride treatment to prevent dental cavities should be seriously considered for people of advanced age, especially those with diminished salivary gland function.

Periodontal Disease

The periodontium consists of the tissues that support the teeth; these tissues are divided into the gums and the attachment apparatus, that is, the structures that hold the teeth in place below the gums. Gingivitis refers to inflammation of the gums primarily caused by infection. Antibiotics can help the condition, but they may have to be used for several weeks.

    Inflammation and loss of the attachment apparatus is called periodontal disease. A variety of oral bacteria have been linked to this inflammation. Eventually the process results in bone loss in the jaw and loss of teeth. It appears that this process occurs over time as a series of specific attacks, rather than as a slowly eroding process.

    Osteoporosis may have oral complications. Some experts suggest that postmenopausal women are at increased risk for developing loss of bone in the structures that support the teeth. (Osteoporosis is discussed in Chapter 17.)

Disorders of the Oral Tissue

Age-related changes in the skin can produce similar changes in the lining of the mouth. Most often, oral changes in older people correspond to the state of their dental hygiene; the condition of dentures; the consumption of drugs, alcohol, and tobacco; and the secretion of saliva. Medical conditions can also affect the lining, allowing yeast infections in the mouth to become established. Older people taking antibiotics on a long-term basis can also develop yeast infections. People who wear dentures may experience irritation due to yeast on the upper part of the mouth beneath the dentures. Approximately 50 percent of these people also have reddish cracks at the corners of their mouth, again due to yeast. Most of these yeast infections respond well to oral medication or ointments.

    Tobacco and alcohol use contributes to the development of premalignant and malignant disorders of the mouth. These disorders are not common but are more likely to occur in older people. Oral cancers account for about 5 percent of all malignancies. Approximately 95 percent of all oral cancers occur in people over 40 with the highest incidence in people in their seventies. While oral cancers can arise in any soft tissue, the back of the tongue on either side and the floor of the mouth are the most susceptible areas, presumably because secretions tend to pool in these areas.

Sensory Disorders

The mouth contains many sensory systems that are essential for normal functioning and quality of life. For example, taste is critical to food enjoyment and for distinguishing spoiled from acceptable food. Other sensations help prepare for swallowing. Many conditions and medications can alter gustatory function. Poor oral hygiene and severe dental disease are common causes that respond to appropriate dental care.

CONDITIONS Thyroid Disease

The normal function of the thyroid gland is to manufacture and secrete thyroid hormones, which directly influence a wide variety of body processes. Thyroid disease is twice as common in older people as in younger people. About 4 percent of people over age 65 have either hyperthyroidism (overactive thyroid that produces too much thyroid hormone) or hypothyroidism (underactive thyroid that does not produce enough thyroid hormone). Up to 9 percent of people in the hospital in this age group have significant thyroid disease. In addition, "subclinical hypothyroidism," where the levels of thyroid hormones in the blood are normal but where the signals from the pituitary gland suggest decreased thyroid activity, occurs in about 10 percent of older people.

    Thyroid disease in elderly people differs from that found in younger age groups. The illness can produce nonspecific, atypical symptoms, often confused with other illnesses and frequently attributed to old age. Older people often have multiple concurrent diseases, and thyroid disease may mask or mimic any one of them, making it difficult to recognize that thyroid disease is present and probably exacerbating the situation. Conversely, coarse hair, dry skin, and constipation, which are important clues to hypothyroidism in younger people, are common complaints in older people with normal thyroid function. Furthermore, when hyperthyroidism develops in older people, the fine hair, moist skin, and diarrhea that are seen in younger people may not be present. Also, some of the drugs used by older people for blood pressure control can hide the presence of hyperthyroidism.

Hyperthyroidism

Hyperthyroidism means that there is too much thyroid hormone in the blood. While the chance of having an enlarged thyroid with one or many nodules increases with age, the more common cause of hyperthyroidism in elderly people is Graves' disease. Graves' disease (named after the 19th-century Irish physician Robert James Graves) is an immune problem caused by an antibody with the remarkable property that it stimulates the thyroid cells.

Symptoms of Hyperthyroidism. People with this condition may have loss of weight, an irregular heart rate, congestive heart failure, and an increased chance of heart attacks. However, they may also have apathy, depression, confusion, loss of energy, and gastrointestinal problems such as constipation, loss of appetite, or a general loss in vitality. As mentioned earlier, the signs that physicians would ordinarily rely on to diagnose hyperthyroidism may be less evident or even absent in elderly people.

Evaluation of Hyperthyroidism. The physician can diagnose hyperthyroidism with specific blood tests that show elevated levels of thyroid hormone. Sometimes an older person with a goiter (a large, swollen thyroid gland) develops temporary hyperthyroidism if given an excessive dose of iodine. This typically occurs after the person has had X ray procedures requiring iodine-containing dye.

Treatment of Hyperthyroidism. In treating hyperthyroidism, the options include antithyroid medicines, surgery, and radioactive iodine ablation (destruction)--the radioactive approach is the simplest, least expensive. Older people generally have normal levels of thyroid hormone 6 to 12 weeks after treatment with radioactive iodine. Four out of five people given this treatment will eventually develop hypothyroidism; consequently, anyone treated with this approach needs to be carefully monitored. In addition, the body's ability to chemically break down various medications may decline after this therapy, and it is important to review and possibly adjust the doses of any such medications. Surgery has a limited role in treating hyperthyroidism. The prolonged use of antithyroid medications usually does not produce a remission in Graves' disease. Permanent remission does not occur if the hyperthyroidism is due to a sudden overgrowth or swelling of part of the thyroid.

Hypothyroidism

Hypothyroidism means that the thyroid gland is not secreting enough thyroid hormone and that blood levels of thyroid hormones are low. In older people, it is most often due to an immune form of thyroid destruction (called Hashimoto's disease after the Japanese surgeon who first described it), or because of earlier treatment for hyperthyroidism (described above).

Symptoms of Hypothyroidism. While most of the signs of this disorder are not very specific in older people (fatigue, constipation, feeling cold, and so on), a puffy face, especially around the eyes, and delayed tendon reflexes (measured by a physician during a neurologic examination) help point to the diagnosis.

    A diagnosis of hypothyroidism can easily be confirmed when blood tests show low levels of thyroid hormone associated with an elevated serum thyroid stimulating hormone (TSH). This elevated TSH is the pituitary gland's attempt to signal the thyroid gland to produce more thyroid hormone.

Treatment of Hypothyroidism. Since thyroid hormone requirements decrease with age, older people who need replacement are started on very low doses of thyroid hormone. Particular caution must be observed when starting treatment in people with underlying heart disease. Usually the blood is checked for the level of thyroid hormone approximately six to eight weeks after treatment is begun. Once the hypothyroidism has been corrected, the chemical breakdown of other medications the person is taking will change, which may require adjustment of their dosage. Older people who have had long-term treatment with dried thyroid extracts called desiccated thyroid preparations should consider a change of treatment using more recently developed synthetic thyroid hormone. The older desiccated thyroid preparations have a very short shelf life and do not maintain a steady level in the blood.




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