Application of Sensory for the Maintenance of Health for the Elderly

Disorders of smell and taste are often diagnostic dilemmas that most times present themselves in elderly people(Croy, Nordin, & Hummel, 2014). The lack of knowledge and insight of these impairment conditions are common and can result in life threatening situations especially among the aged. In addition, poor appetite   is a challenge faced by elderly people living both at home or in nursing care homes. Poor appetite can result in nutritional deficiencies and weight loss and is linked to poor health outcomes and mortality. By gaining an understanding on what causes reduced appetite and its link to sensory impairment, clinical staff and nurses can quickly identify elderly patients that have an impaired appetite. Several strategies can be utilized in promoting appetite and increasing intake of food (Pilgrim, Robinson, &Save, 2015). When the human tongue receives taste signals, a number of neural pathways are activated. However, these pathways don't require for food to be in the mouth for them to be activated; the sound of rattling dishes, or an image of food can cause the stomach to rumble. The sense of vision provides a critical sense with regard to food perception, driving preferences and raising expectations. Humans discriminate unconsciously, between foods that are low and high in calories, by just looking at the said food. Looking at images of food that are low or high calorie provokes different responses with varying intensities in the brain(Toepel, Ohla, & Hudry, 2014). The study by Toepel et al.,( 2104) tested subjects where they were shown images of high calorie foods such as pastry, pizza, salmon, and lamb chops which were alternated with images of low calorie foods such as pasta/tomato sauce, yoghurt, watermelon, and beans. For every image observed, a weak electric current was attached to the tongues of the participants which stimulated the state function of the brain without any real taste being mimicked. This produced a metallic taste and sensation hence, the a food cue was initiated by the   images and neutralized by the metallic stimulation. The results from the EEG measurements showed that looking at high calorie images stimulated pleasant and strong sensations as opposed to the low calorie food images. The high calorie images evoked neural activity which was stronger in some parts of the brain such as frontal operculum and the bilateral insula in comparison to images of lower calories. Any taste pleasantness changes activated the medial orbitofrontal cortex. Shape also affects taste as was studied by Gal in a research that analyzed consumer behaviour against marketing. In the study, the participants first sorted geometric figures after which they were shown a piece of cheese that had pointed corners rather than the usual round ones. The subjects described the taste of the cheese as being sharper (Bakalar, 2014). However, understanding the brain's mechanism that connects between gustatory and visual senses is still a relatively new In addition to visual and shape, odour too plays a significant role. Volatile molecules are released when a person chews food which then travel to the receptors at the back of the mouth that lines the nasal passages. The receptors are what enable a person to identify the different sensations' combinations which result in flavour- knowing what one is consuming. When a person eats sour or sweet strawberry, the mouth is able to detect this even while the nose is held tight (Stevenson, 2012). Hearing too plays a part in what people eat. If for example one hears the crunch of potato crisps, one imagines the crisps to be fresher. Taste can also be affected by sound as was demonstrate by a study where participants were asked to bite into crisps and rate their freshness and crispiness. The researcher played a crunching sound once the subject took a bite and which systematically changed the perceptions by the subjects where the subjects stated the crisps were crispier and fresher compared to when there was no aural cue (Spence,2015). Temperature also is a factor that determines one's perception of taste. For example, warming ice cream increases the perceived flavour. Sensitivity to temperature is regulated by the taste buds' molecular processes that are responsible for the different tastes (Amerine, Pangborn, & Roessler, 2013).   Increasing food temperature to 15-35 degrees Celsius enhances one's sweetness neural response. In approximately half of the population, cooling or heating the tongue causes taste sensations in that, cooling the tongue increases the salty or sour tasting sensations while increasing the temperature increases the taste sensation of sweetness.   Smell when compared against taste, is more complex as human receptors for taste are fewer than receptors for smell. The five taste receptors are umami, bitter, salty, sour, and sweet. There are various ways of mixing both smell and taste leading to a broad array of flavours that a person perceives and which bear little subjective resemblance to the aforementioned tastes. There is a neurological link between taste and smell that is unique to the two senses. When one sees and hears something simultaneously, two different neurological pathways are used while this is not the case with tasting and smelling. For example, when one pops a jellybean in the mouth while holding the nose tight, one can still sense the jelly beans' sweetness but will not perceive the flavour. Once a person releases the nose, the flavour becomes identifiable. The flavour thus comes from the nose even when one tastes the sweetness of the beans (Society for Neuroscience, 2015). There is a distinction between smelling via the nose and via the back of the throat, while there is a neurological distinction in the tasting. Arrival of the retronasal and orthonasal odours is via the same route however, when they arrive simultaneously as taste, integration of taste and odour occurs which creates the perception of flavour. Flavour is only perceived through the simultaneous arrival of odour and taste to the anterior insula. Hence, it is concluded that the overlapping of the distinct smell and taste pathways occurs in the anterior insula. When molecules bind in the tongue receptors, then the sense of taste can be perceived which proceeds to send signals to various parts of the brain to eventually meet at the anterior insula (Yin, Hewson, Linforth et al., 2017). Further, a person is able to differentiate the experience with food through touching the food. This is more so, with regard to true fats (an example is the creamy taste of ice-cream and butter). There are specific neurons in the brain's orbitofrontal cortex that respond to fats texture in the mouth such as fat rich foods including chocolate and ice cream as well as similarly oily non food substances such as silicone oil and mineral oil. In addition, the taste of soda is influenced greatly by feel where a flat soda tastes different from a carbonated one (Drewnoski & Almiron, 2010).  Ã‚   The proportion of elderly is escalating fast in the world. It is estimated that by 2025, there wil be 1.12 billion people aged 60 and above with most having some level of sensory loss including smell and taste perception (Coreira, Lopez, &Wroblewsski et al., 2016). Laboratory and clinical studies have shown a decline in smell and taste functioning among persons aged 60 years and above which increases in severity in those aged 70 years and above. Dysfunction of smell and taste is caused by ageing and some specific disease conditions such as Alzheimer's and cancer, surgical and pharmacological intervention, environmental and radiation exposure. The chemosensory deficits may result in alteration in food choices and consumption and subsequently worsen any existing medical conditions, compromise immunity and nutritional status, change food choices and result in decrease in weight (Doty & Kamath, 2014).   As has been discussed earlier, vision, smell, and taste are involved in food enjoyment. When these senses are impaired due to ageing, they result in a reduction in appetite among the elderly. Appetite is stimulated by the smell of food while the taste of food promotes its enjoyment and stimulates the appetite further even after eating. Most elderly people have taste and smell senses that are impaired and which hinders their appetite to a great extent (Nieuwenhuizen et al., 2010). Having a good vision helps in stimulating one's appetite (Spence, Okajima, & Cheok et al., 2015). As one ages, the vision reduces with 1 in 5 persons aged 75 years and above and 1 in every 2 persons aged 90 years and above having loss of vision (RNIB, 2014). The body composition of an individual is what determines his/her energy requirements and more so, the fat free mass (the component s of the body that are exclusive of fat for example organs, bones, and muscles), and their physical activity levels.   As people age, they lose the fat free mass with a 1% rate of skeletal muscle loss among those aged 70 years and above. With most being physically inactive. Therefore the energy requirements among the elderly are low which is a contributory factor to appetite loss. This varies among individuals, which is reflective of the body composition differences as well as physical activity differences (Milanovi?, Panteli?, & Trajkovi? et al., 2013). As people become older, the sense of smell deteriorates with declining olfactory functioning (Doty & Kamath, 2014;Smoliner, Fischedick, &Sieber et al., 2013).  In addition to losing the sense of smell, people lose the ability to differentiate smells with more than 75% of persons aged 80 and above experiencing acute olfactory impairment with increased continuous decline after 70 years (Doty et al., 2014). Of persons aged between 80-97 years, 62.5% had olfactory impairment(Schubert, Cruickshanks, &Klein et al., 2011). However, taste impairment is more common than olfactory impairment (Malaty & Malty, 2013) Gustatory dysfunction is also linked to ageing, however, most often, what is thought to be taste impairment is in fact an olfactory impairment. Besides smell impairment, taste impairment is caused by prior infection of upper respiratory area, drug use, head injury, as well as idiopathic causes (Fomazieri, Borges, & Bezerra, et al., 2014; Bromley & Doty, 2014; Roper, 2013).  Problems with chewing caused by loss of teeth and dentures can interfere with sense of taste along with decreased production of saliva. Decreased senses of tastes and smell causes suppression of appetite which results in loss of weight, impaired immunity, malnutrition, and medical conditions deteriorations (Phillips, Caroll, & Drayson et al., 2015; Jacobson, Green, & Murphy,2010).  Problems with nutrition form a significant sequeale from disorders of taste and smell.  Elderly persons need two-three times more salt concentration in tomato soup before they are able to detect it (Ahmed & Haboubi, 2010).  The tendency for the elderly to take in higher concentrations of sugar and salt can exacerbate already hazardous medical conditions they may be experiencing. A decrease or distortion in the sense of smell results in a decrease in life quality or even disability(Smeets, Veldhuizen, & Galle, 2009). Further, such medical conditions can result in a high level of depression and anxiety in the person. Anxiety resulting from inability to enjoy the taste of food and fear that the taste impairment could be as a result of a n unknown condition. In addition, there is also heightened depression among persons with anosmia (Hummel, T., Landis, B. N., & Hà ¼ttenbrink,, 2011).   Classification of chemosensory dysfunction is as follows: ageusia (loss in sense of taste), hypogeusia (decrease in taste sensitivity), dysgeusia (normal taste distortion), anosmia (loss in of the sense of smell), hyposmia (decrease in smell sensitivity) and dysomia (normal smell distortion). Persons with hypogeusia often need tastants in higher concentrations in order to detect the same; their threshold for detecting and recognizing tastants is elevated above the normal controls. These group of persons also have less intense suprathreshold concentrations. Persons with dysgeusi experience taste distortion such as metallic/bitter taste sides that are not often linked to the foods they are consuming. Analogous impairments in perceptions of smell are often reported in persons with dysosmia and hyposmia. The chemosensory deficits that the elderly experience are irreversible. However, there are several sensory interventions that can be applied such as odour and taste intensification to compensate for perceptual loss that is age related. One such method is addition of monosodium glutamate (MSG) in food during and after its preparation to enhance its taste and smell as well as enhance its palatability. When a person presents with taste and smell disorders, they will first need reassurance and counselling that they are not suffering from an infection or malignant disease. Once diagnosis of diminished smell is done, the management goal will entail injury prevention that is related to the condition. Gas detection visual stimulating devices are ideal for a person that use gas stoves as such a person will be incapable of smelling a gas leak. Neighbours and relatives will need to be involved in assisting such a person as he/she may be unable to detect spoiled food which can cause food poisoning if consumed. MSG is the glutamic acid sodium salt that poses the unique umami taste quality. The term umami is Japanese with no English translation , and is used for describing the MSG taste as well as the taste of certain broths and fish. The umami taste is similar to the protein taste. Different tests have shown that umami does not fall in any of the categories of bitter, salty, sour, and sweet. MSG is used in making commercial mixtures that contain specific 5†²-ribonucleotides such as IMP (inosine-5†²-monophosphate) and GMP (guanosine-5†²-monophosphate). MSG together with these compounds have synergistic and potent effects, including a significant decrease in the threshold levels of MSG. A person with a taste disorder will need flavoring enhancements added to his/her food. Flavors are a combination of odorant molecules which are blended or extracted from natural product or can be synthesized from natural products through   mass spectrographic and chromatographic analysis. Flavor enhancers modify or enhance the food's original aroma or taste but lack their individual aroma or taste. For example, simulated beef flavour can be used as an addition to beef or beef soup to increase the beef sensation. There is a difference in flavour enhancement from the more common taste and odour sensation enhancers such as salt, herbs, and spices. Herbs and spices add diverse flavours as opposed to intensifying the food's existing chemosensory properties. Flavours are not spices hence they do not cause any stomach or mouth irritations. The main component in flavour enhancements is salt but also, MSG is used often. Flavour enhancement added in food for the sick and elderly can improve the palatability of food and also its acceptance, slow or reverse decline in functionality, increase counts of lymphocytes, and improve the overall quality of life. It also potentially makes up for anorexia (Islam, Fagundo, & Arcelus, 2015).One study revealed that enhancement of flavour for the elderly living in a retirement home resulted in an enhanced immune status as witnessed in levels of B and T cell counts and also an improved strength in grip (Islam et al., 2015). In addition, odour and taste stimulation among the elderly has been shown to improve with an increased salivary IgA rate (Philips et al., 2015) Several factors contribute to impaired appetite among the elderly and these are often linked to the psychological and physical alterations that come with ageing. Poor appetite is significant as it increases the likelihood of a person becoming nutritionally deficient and even losing weight. Weight loss is particularly difficult to regain in elderly patients and along with nutritional deficiency, they are both associated with mortality and poor health outcomes. The nurse is in a position to quickly identify patients that have impaired appetite and can commence on interventions to help the elderly patients to enhance their appetite and increase food intake by utilizing different strategies as discussed in this paper. These strategies include flavoring food with sauces, spices, and herbs, improving the ambience of food, ensuring the patient has company while eating, serving meals that the patient has shown preference for and during regular times when the patient eats. Amplification of fo od taste and flavor using MSG can improve the palatability of the food and its acceptance as well. 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