Who were the investigators, and what were the aims of the studies? Helping older adults improve their balance is an important way to help lower the risk of falling. Tai chi, an ancient Chinese martial art, enhances body awareness. Previous research had shown that tai chi is an effective approach to improving balance, but whether it could be used with typical community-dwelling older adults was unknown. Li et al. (2008) examined whether using tai chi to improve balance could be implemented in a community – based senior center.

How did the investigators measure the topic of interest? Each Tai Chi—Moving for Better Movement class began with warm-up exercises, followed by teaching and practicing the 8-form variation of tai chi for 45 minutes, and ended with a 5-minute cooldown period. Program effectiveness was measured as the change in physical performance and quality of life as indexed by the functional reach test, the up-and-go test, time to rise from a chair, the 50-foot speed walk, and a 12-item physical and mental health scale. Frequency of falls was monitored monthly using a falls calendar in which participants marked when falls occurred. Long-term maintenance of the program was measured as the degree to which participants continued during the 12 weeks after the formal program ended.

Who were the participants in the study? Participants were 140 community-dwelling adults in Oregon who were over age 60, in good health, physically mobile, and did not show any mental deficits. The study was conducted in senior centers.

What was the design of the studies? The researchers used a pretest-posttest design to measure change. Participants

took the one-hour tai chi classes twice per week for 12 weeks.

Were there ethical concerns with the study? Participants in the study were provided with informed consent and were closely monitored throughout the study, so there were no ethical concerns.

What were the results? Results showed that participants improved on all measures during the course of the program. No loss of improvement was observed in the 12 weeks following the end of the formal program.

What did the investigators conclude? Li and colleagues concluded that tai chi represents an effective intervention to improve older adults’ movement to lower the risk of falling. It was easily adapted in senior centers, making it a low-cost, high-payoff intervention. Because tai chi is a low-impact martial art, it is easily adapted for use by older adults.

Because fear of falling has a real basis, it is impor­tant that concerns not be taken lightly. Older adults can be taught to pay greater attention to other cues, such as somesthetic ones. During times of dizziness or vertigo, people can learn to attend to the position of lower body limbs to better use this feedback in adjusting posture (Hu & Woollacott, 1994a, 1994b). People can also be trained to prevent falls through tai chi (Li et al., 2008), described in detail in the How Do We Know? feature.

84 CHAPTER 3

Taste and Smell

Taste. There is an expression “too old to cut the mustard" which dates back to when people made mustard at home by grinding mustard seed and adding just the right amount of vinegar (“cutting the mustard”) to balance the taste. If too much vinegar was added, the concoction tasted terrible, so the balance was critical. Many families found that older members tended to add too much vinegar.

Despite the everyday belief that taste ability changes with age, we do not have much data docu­menting what actually happens. We do know that the ability to detect different tastes declines gradu­ally and that these declines vary a great deal from flavor to flavor and person to person and the amount of experience one has with particular substances (Bitnes et al., 2007). Whatever age differences we observe are not caused by a decline in the sheer number of taste buds; unlike other neural cells, the number of taste cells does not change appreciably across the life span (Whitbourne, 1996a).

Despite the lack of evidence of large declines in the ability to taste, there is little question that older adults complain more about boring food and are at risk for malnutrition as a result (Henkin, 2008). The explanation may be that changes in the enjoyment of food are caused by psychosocial issues (such as personal adjustment), changes in smell (which we consider next), or disease. For instance, we are much more likely to eat a balanced diet and to enjoy our food when we do not eat alone and when we get a whiff of the enticing aromas from the kitchen.

Smell. “Stop and smell the roses" “Ooh! What’s that perfume you’re wearing?” “Yuck! What’s that smell?” There is a great deal of truth in the say­ing “The nose knows" Smell is a major part of our everyday lives. How something smells can alert us that dinner is cooking, warn of a gas leak or a fire, let us know that we are clean, or be sexually arous­ing. Many of our social interactions involve smell (or the lack of it). We spend billions of dollars mak­ing our bodies smell appealing to others. It is easy to see that any age-related change in sense of smell would have far-reaching consequences.

Researchers agree that the ability to detect odors remains fairly intact until the 60s, when it begins to decline, but there are wide variations across people and types of odors (Aldwin & Gilmer, 2004). These varia­tions could have important practical implications. A large survey conducted by the National Geographic Society indicated that older adults were not as able to identify particular odors as younger people. One of the odors tested was the substance added to natural gas that enables people to detect leaks—not being able to identify it is a potentially fatal problem.

Abnormal changes in the ability to smell are turn­ing out to be important in the differential diagnosis of probable Alzheimer’s disease, resulting in the development of several quick tests such as the Pocket Smell Test (Steffens & Potter, 2008). According to several studies, people with Alzheimer’s disease can identify only 60% of the odors identified by age- matched control participants; in more advanced stages of the disease, this further declined to only 40% compared with controls. These changes give clinicians another indicator for diagnosing sus­pected cases of Alzheimer’s disease.

The major psychological consequences of changes in smell concern eating, safety, and pleasurable experiences. Odors play an important role in enjoy­ing food and protecting us from harm. Socially, decreases in our ability to detect unpleasant odors may lead to embarrassing situations in which we are unaware that we have body odors or need to brush our teeth. Social interactions could suffer as a result of these problems. Smells also play a key role in remembering life experiences from the past. Who can forget the smell of cookies baking in Grandma’s oven? Loss of odor cues may mean that our sense of the past suffers as well.

Concept Checks

1. What major structural changes in the eye occur with age? What functional effects do these changes have?

2. How does hearing change with age?

3. With age, what changes occur in somesthesia and balance?

4. How do the abilities to taste and smell change with age?