March 5, 2007
Betrayed By Our Bodies — Sensory Loss in Aging
By Dan Orzech
For The Record
Vol. 19 No. 5 P. 28
Loss of vision, hearing, taste, smell, and touch damage the quality of life for older adults, but rehabilitation is available for some losses and health professionals continue to seek solutions for others.
How can a spoonful of gravy improve the quality of life for an older adult?
As we age, we gradually lose our ability to identify smells and tastes—two senses that play a key role in food enjoyment. That not only plays havoc with elders’ nutrition, it also contributes to social isolation because food serves as a major social function.
Scientists are finding, however, that a little gravy or other sauce on food can help activate taste buds of older adults, helping them taste and smell their food, thus enjoying it more.
That’s one of the surprisingly simple findings emerging from a growing body of research examining the often-unexpected ways sensory loss affects us as we grow older.
Taste and smell aren’t the only senses that diminish as we age; so do vision and hearing. Even our sense of touch diminishes with age. And, according to researchers, sensory loss plays a much larger role than we may realize in how seniors function in the world. Armed with the right knowledge about which age-related sensory losses are normal and which are not—and what to do about them—healthcare professionals can make a big difference in older adults’ quality of life.
A Cruel Biological Joke
Sensory loss can profoundly impact social relationships. For example, take macular degeneration, the most common age-related vision disorder among older adults.
In a sort of cruel biological joke, macular degeneration robs people of their ability to see objects in the very center of their visual field, says vision loss expert Cynthia Stuen, DSW, senior vice president for services and education at Lighthouse International in New York, a nonprofit agency specializing in vision loss. “You could be walking down the street and look right at someone,” she says, “but not recognize them. Then they say, ‘I saw so-and-so the other day, and he snubbed me. He didn’t even say hello.’”
The vision problems caused by diabetes—diabetic retinopathy, which makes vision blurry and uneven—can create entirely different social problems for older people. Diabetes can cause fluctuations in vision, depending on the time of day or food intake. “At 10 in the morning,” says Stuen, “someone with diabetes may be able to see a quarter on the table. At two in the afternoon, he can’t. You can easily imagine his spouse saying, ‘He can see more than he lets on.’”
Other forms of vision loss such as hemianopsia (losing sight in one half of the visual field) can go completely unnoticed not only by patients but by doctors as well, causing tremendous chaos in older people’s lives. Hemianopsia stems from damage to one side of the brain, typically from a stroke or trauma to the head, which destroys sight on the same side of both the right and left eyes. Since patients still have some sight in both eyes, the vision problem is often not realized, even by neurologists, says Stuen.
Without half of their visual field, however, simple tasks such as reading become practically impossible. “The person doesn’t realize that there’s still half a line of text remaining and wonders why nothing makes sense,” Stuen says. “It can be very frustrating because they can’t read, and they don’t know why until it is properly diagnosed.”
Since our peripheral vision lets us become aware of approaching objects in an almost unconscious way, people with hemianopsia—or vision disorders such as glaucoma, where side vision is also lost—can be startled when a car or other fast-moving object seems to appear suddenly out of nowhere. Patients may run into objects, trip or fall, or have panic attacks in crowded places. Not surprisingly, some become reluctant to venture out by themselves.
Depression and the Eyes
Many people in the helping professions aren’t aware of the issues posed by sensory loss, says Stuen. Older people who have had diabetes for an extended period of time, for example, are strong candidates for vision loss. “Any time someone has diabetes [for] more than seven years,” she says, “you’re very likely to find the early signs of vision impairment.”
Nor are some aware of the connection between vision loss in older adults and depression. Older people with vision impairment are anywhere from two to five times more likely to suffer from depression than someone without vision impairment. Between one quarter and one third of visually impaired elders report a significant number of depressive symptoms.
Surprisingly, the extent of the vision loss doesn’t necessarily matter in terms of who becomes depressed. Older people with even minimal vision impairment are just as likely to become depressed as those with severe impairments. In fact, seniors who are legally blind in one eye are more likely to be depressed than those legally blind in both eyes. The reason, researchers speculate, is the distress caused by the uncertainty about losing eyesight in the remaining eye as well.
Seeing to Drive
For many older people, losing their mobility and subsequent independence can also contribute to depression. That makes driving a big issue for older adults who are losing their vision, says Amy Horowitz, DSW/PhD, director of research at the Jewish Home and Hospital Lifecare System in New York. Horowitz is conducting a study funded by the National Institutes of Health examining the process older adults and their families go through when deciding when to stop driving.
“Older people sometimes hide their vision loss from their families,” says Horowitz, “because they don’t want to lose their ability to drive. Many of them will go to their eye care professional for an assessment, however, to find out if it’s OK for them to drive. The families struggle with it because they’re not always the ones the older person listens to.”
Many older adults will self-regulate their driving, sometimes for extended periods, before they stop completely. “They’ll stop driving at night, they won’t drive during rush hour, or they won’t drive during bad weather,” says Horowitz.
Planning ahead can help make the transition easier, according to Horowitz. It’s important to look at the transportation options available in the community and how family and friends can help, especially in the United States, which doesn’t have as good a public transportation system as Europe. Sometimes, however, “there are just no transportation alternatives, and you really can have the potential for isolation,” she says.
Vision loss is relatively common in older populations. More than one quarter of adults aged 75 and older report problems with their sight, even when wearing their eyeglasses or contact lenses, with still higher rates found among African and Hispanic Americans. But losing other senses is also a problem.
Roughly 30% of adults over the age of 65, for example, have some hearing loss. Aging by itself can take a toll on hearing, and occupational or recreational noise, genetic factors, and trauma can all make hearing loss worse. So can vascular disease, infections, and some diuretics and chemotherapy drugs. An increase in wax production in the ear, often found in older adults, can also contribute to hearing problems.
As with vision loss, the result can be social isolation. Hearing loss interferes with face-to-face communication and makes using the telephone more difficult. It can often cause older adults to lose interest in activities that used to give them pleasure and make them more likely to miss instructions from their doctor or pharmacist about their medications. Some studies also show a link with depression, although the connection is less clear than in the case of vision loss.
Smell and Taste
While vision and hearing loss attract the most attention, our sense of smell and taste diminish with age as well. Because the decline is usually gradual, many elders and their caregivers may not be aware that it’s happening.
Losing the ability to smell and taste can bring very real problems. Seniors who have a decreased sense of smell may not realize that the meat they’ve just taken out of the refrigerator is spoiled, says Nancy E. Rawson, PhD, a scientist at the Monell Chemical Senses Center in Philadelphia. They may not be able to smell smoke from a fire in their residence until it’s too late to escape or notice the smell of leaking gas. “The odor that’s added to natural gas,” Rawson says, “is one of the odors that people lose sensitivity to first.”
Losing our sense of smell and taste can also influence what we eat, which can have a big impact on elders’ health and quality of life. As they lose their sense of smell, says Rawson, seniors’ food selection frequently becomes less varied. “They will often start using more salt and sugar,” she says, “because that’s what they can perceive.”
That, of course, is exactly the opposite of what they should be doing. “Everybody is telling them to eat less salt and less sugar,” Rawson says. “But what that’s really saying to them is eat food that has no taste.”
Also, doctors and dietitians are typically advising them to eat less fat. But many flavor compounds are fat-soluble, says Rawson, so having fat in food is essential to having flavor in food. Remove the fat, she says, and you remove the flavor.
Adding some butter or gravy to food can help make the aroma and flavor chemicals more available to taste buds, says Rawson. And it doesn’t take a large quantity to dramatically improve the enjoyment of food. “A tablespoon of gravy or a little bit of olive oil can go a long way toward bringing back flavor and improving quality of life for the elderly,” she says.
Gravy can help in another way. Chewing and salivation play a key role in releasing flavor compounds in food. Dentures or reduced salivary flow can interfere with that process, says Rawson. So can dehydration, which is common in older adults. “If you look at almost any medication that people over 60 take,” she says, “one of the side effects is dry mouth. So using sauces or having liquid with the meal can help.”
The Color of Food
Taste and smell are not the only senses that play a role in how our food tastes. How it looks is important, too.
“Information from all of our senses is integrated in the brain,” says Rawson, “and combine to influence how we perceive our food. What you’re looking at on your plate feeds back into your nose and mouth to modulate your olfactory perception and sense of taste and vice versa.”
Research has shown, for example, that color in food has a big effect on the perceived intensity of flavor. People tasting two glasses of colored sugar water, with identical concentrations of sugar, will rate one that is a bright cherry red as more intensely sweet than one that is yellow.
For older people who may have trouble getting adequate nutrition, how their food looks can be important. Unfortunately, says Rawson, nursing home kitchens often overcook food, robbing it of much of its color and appeal.
With taste, smell, and sight all playing key roles in how our food tastes, losing any one of them can have a significant impact on older adults’ quality of life. A decline in more than one of the senses, not surprisingly, can pose even greater—and often unexpected—challenges.
Seniors whose sense of smell no longer allows them to detect smoke from a fire, for example, may count on smoke detectors in their house to alert them to a blaze. If their hearing is poor as well, however, and they take their hearing aids out at night, the smoke detector’s audible alarm may be useless.
Many older adults who are losing their hearing will rely on their eyesight to compensate for the hearing loss. In conversation, they’ll watch the other person’s lips and face and use clues about the context to try to respond appropriately. Patients who are losing both their hearing and their vision, however, don’t have that option.
Research shows that anywhere from 4% to 21% (depending on the definitions used) of elders have a dual sensory impairment—and Stuen believes the data underreports the extent of the problem.
The specific nature of the sensory loss can have a big impact on the problem’s severity. With macular degeneration, elders lose sight in the center of their visual field. “That eliminates their ability to see a face and read lips,” says Stuen, “which will have a more profound effect on their hearing than if they have glaucoma, where they lose their peripheral vision but still have their central vision.”
It’s common for people with macular degeneration to report that their hearing is getting worse, says Stuen, when the main culprit is actually their vision loss. If they can’t compensate for the hearing loss by using visual cues from lip reading or facial expressions, they may perceive their hearing to be declining.
Maintaining Independence Through Rehabilitation
Sensory loss seems to be an almost inevitable companion to growing old. Does that mean older adults who are losing one or more of their senses are simply out of luck? Not at all, say those who work with sensory impairments.
“We don’t have cures for the major causes of age-related vision loss,” says Stuen, “but we have made great strides in the area of rehabilitation.”
Vision rehabilitation specialists, or ophthalmologists, optometrists, and occupational therapists with specialized training, can help older people find alternative ways to safely accomplish daily tasks, enabling them to maximize their independence.
Magnification is one major area of low vision rehabilitation, says Stuen. With magnification, someone with macular degeneration may be able to use their side vision to read something. That may be enough for older people to read their mail or write their own checks, reducing their dependence on others.
Other vision rehabilitation therapists, called orientation and mobility specialists, can help seniors with the challenges involved in moving around, both in their own homes and getting to a job, shopping, or social functions.
Those working with older adults often aren’t aware of the existence of vision rehabilitation services, in large part because they’re often not covered by health insurance policies. That is beginning to change with a new five-year Medicare demonstration project, which is providing coverage for these services in New York City, Atlanta, North Carolina, Kansas, Washington, and New Hampshire.
— Dan Orzech is a Philadelphia-based freelance writer.
Researchers are discovering that our sense of smell can help improve the early diagnosis of these diseases. “Changes in our olfactory pathway occur before changes elsewhere in the brain in Alzheimer’s disease,” says Nancy E. Rawson, PhD, a scientist at the Monell Chemical Senses Center in Philadelphia. “These changes can be detected using odor identification tests. People with early-stage Alzheimer’s perform more poorly on those tests than others their same age.”
Similar changes in our ability to smell can provide early clues to Parkinson’s. Combining these tests with other information, says Rawson, can significantly improve the accuracy of early diagnosis for both diseases.
But losing the ability to smell in old age doesn’t necessarily mean a diagnosis of Alzheimer’s or Parkinson’s. “People lose their sense of smell for many reasons,” cautions Rawson. “By itself, without any other symptoms, loss of smell is not a sign of anything other than loss of smell.”