A ging is a complex process that occurs continually from birth to death. It is not a singular event that takes place according to chronological age but varies from individual to individual in relation to genetic make-up, life experience, environmental factors, and other events yet to be discovered. One aspect of the normal aging process is the accumulation of declining capacities in the sensory and perceptual functions. As in the total process of aging, the decrements in sensory functions have their onset at different ages and proceed at different rates.1
Of all the senses, vision and hearing appear to be the most crucial in terms of independence, autonomy, and adjustment to aging. Deficits in audition or sight may lead to increased isolation, often resulting in further sensory deprivation and disorientation.
Degeneration in vision and audition have one major difference; audio loss is usually symmetrical, while visual loss is often assy metrical.2 Miller and Stern1 found that although degenerative changes of age do affect vision, at least one eye is able to somehow perform with a youthful vigor. In their study 83% of the subjects had vision better than 20/40 in one eye and 31% had vision of 20/20 in the better eye.
Vision in the elderly is frequently affected by the condition of the lens of the eye. The lens is the transparent part of the eye that focuses light rays to form an image on the retina. Changes in the aging lens interfere with the refraction and transmission of light, producing an increase in the absolute threshold for vision. There is a gradual progressive accumulation of inert tissues at the center due to the compressions and shrinkage of the nuclei and cell membranes of old fibers. The central region of the lens becomes less transparent and the lens capsule becomes more yellow, thicker, and less permeable.3
Because of the decrease in lens elasticity, presbyopia or loss of accomodation occurs at older age. Constriction of the pupil reduces the amount of light entering the eye and focuses the light through the densest part of the lens. Yellowing of the lens also alters color perception because it absorbs blue light selectively. Objects appear more yellowish to the elderly and some have difficulty distinguishing between blue and green.4 Hearing loss appears to be an almost inevitable concomitant of older age. Of the four and one half million people with hearing loss, 80% are over 45 years old; 55% are 65 and older. The rate of decrement in sensitivity seems to vary among populations, depending upon the individuals' history of exposure to noise and their homogeneity with respect to heredity and environmental factors.s
"Presbycussis" is hearing loss which occurs with advancing age, and it may be mainfested in a number of ways. There may be sensory dysfunctioning due to progressive degeneration of hair cells in the organ of Corti. The cells gradually become fewer in number, and changes are most marked in the basal turns of the cochlea where high pitched sounds are picked up. The result is a high pitch deafness in which an individual may have difficulties in hearing the telephone right or a bird singing, or he may be unable to distinguish consonants such as "s," "f," or "z."6
Neural dysfunction is related to presbycussis producing a decrease in the neuronal propulation of the cochlear nerve. In this instance speech discrimination is the cause of hearing deficit-that is, the individual is unable to distinguish one word from another even though he is able to hear them. Metabolic deficiencies such as atrophy of the stria vascularis may also cause deafness by producing an equal threshold loss for all frequencies. Finally, the cause of hearing loss may be mechanical, such as in the alteration of the motion mechanics of the cochlear partition.1
A most commonly associated condition causing deafness in older age is wax accumulation. Wax that is normally absorbed in the younger person's ear becomes hard and collects in the meatus.6 This may cause a blockage to receptor cells so that hearing may become significantly diminished. Older people are often unaware of this phenomenon or may be embarrassed about their "dirty" ears.
It is difficult to document high degrees of loss in the other three senses-touch, olfaction, and gustation. It is hypothesized that there is a general decline in the sense of smell, but little has been found in the literature to verify this. In other studies, it has been shown that there is a gradual decrease in the number of taste buds, especially after the age of 50. There are changes in salty, sweet, sour, and bitter tastes in that order, and the most dramatic decrements are noted in salt sensitivity, especially in men.3
Touch and pain sensitivity decrease sharply after the age of 50 and it is thought to be due to a decrease in the number of Meissner's corpuscles and other receptor organs in the skin. The lower extremities are more affected by a lessened touch sensitivity with older age, while the upper extremities and forehead are more affected by a diminished pain sensitivity.4
The Role of the Nurse in Teaching Self-Assessment
The nurse can play an important part in teaching the older person to become aware of the sensory losses in himself and others. The senior center provides an appropriate forum for teaching and learning through small group and one-to-one interactions. As a practitioner the nurse can also make baseline assessments of her clients and, working together, she and her client may note changes taking place over time. If noticeable sensory deficits occur, the nurse is in an excellent position to coordinate care and treatment to help the client to cope successfully in his environment. Prevention of further unnecessary losses may also be achieved through teaching and assessment.
A Senior Center Program
A program involving normal sensory loss in the older person was presented at a senior center where approximately 50 elderly persons gathered for socialization and a hot midday meal. It was given over a period of seven weeks and consisted of small group analyses of each of the senses during the first five weeks, a summary of sensory loss and the need for awareness and self-assessment in the larger group, and a small group follow-up. During this experience it was found that small group work with the elderly is much moré satisfactory than dealing with a larger group. They are more apt to hear what is being said, to see what is being illustrated, and to respond appropriately.
The first sensory modality that was analyzed was olfaction. Coffee, tea, garlic, mustard, vinegar, Comet cleanser, and Russian tea consisting of spices such as nutmeg and cinnamon were tested by putting them in paper cups covered with perforated aluminum foil. The participants were asked to sniff the contents of the cups and identify them. It was found that the most pungent odors such as vinegar and the nutmeg and cinnamon were most easily recognized, while the more innocuous odors such as coffee and tea were the most difficult to discriminate.
The second week involved hearing assessment which was accomplished by using a homemade tape recording to test for pitch and word discrimination. High and low frequencies were determined by playing a range of notes on a piano, a trombone, and a flute. A simple reading using a man's bass voice and a woman's soprano voice was done in both a fast and a slow pace. The result was that people with word discrimination deficiencies were able to hear both high and low frequencies equally well, but were unable to understand the passages that were read at a faster tempo. Those individuals whose hearing was diminished in the higher ranges were able to hear the low notes more easily and could hear the bass reading rather than the soprano regardless of the speed in which it was read.
Vision was tested the third week in the areas of color discrimination and glare. Color strips were placed in a row in two different orders on black and white paper (black, purple, blue, green, yellow, red, orange and purple, green, orange, blue, yellow, black, red). Signs were also made on glare and nonglare paper in various sizes of print and in various color combinations. The participants scored extremely well in all areas of testing, but it was found that they were able to read the words best that were in sharpest contrast to the background color, especially black lettering against a yellow background. Also some difficulties were seen in attempts to distinguish blue from green against the black paper when the two colors were placed directly next to each other.
Taste testing for sour, sweet, and salt was carried out on the fourth week using popcorn and lemonade. The saltiness of the popcorn ranged from none used to extremely salty; the sweetness of the lemonade ranged from sour or no sugar to extremely sweet. There were four graduations in each test. The majority was able to discriminate degrees of sweetness in the lemonade and preferred the least sweetened flavor; all reactedstrongly to the unsweetened sour taste. The salty taste was distinguished less easily, and more men had difficulty than women. Some men said that all degrees of saltiness tasted the same and were only able to distinguish between salt and no salt.
The sense of touch was tested by putting variously shaped and textured objects in a paper bag. An individual was asked to pick out the various objects and identify them by feeling them with his eyes closed. Most people were able to identify all objects exceptfor a small battery that was commonly mistaken for a lipstick. Objects with most distinct shapes and textures such as a shell and a paperclip were most easily identified.
These tests were not meant to be either scientifically perfect measurements or a proving ground for sensory loss. They were intended to stimulate awareness of what happens to people in normal aging and to point out the individuals differences in the process. The program that was presented to the larger group consisted of summaries of all of the reactions to the tests and the relationships of our test results to those of other investigators. Emphasis was placed on self-assessment and awareness of one another's losses. Methods of coping with various sensory losses were stressed such as color contrasting and proper lighting in the home; the appropriateness of hearing aids, lip reading, and speaking slowly or in a low voice; avoidance of extremes of heat and cold; and substituting other spices for large amounts of salt in food. A follow-up session was held for individuals and small groups in order to answer questions and aid people in self-assessment.
Implications for the Future
Many criticisms have been aimed at our health care system in the United States, and it is widely felt that emphasis should be geared toward prevention rather than sick care. The gerontological nurse can play an important role in teaching the elderly self-assessment and assisting them in anticipating and recognizing change. One of the most logical places for teaching and learning is in the senior center where elderly persons who are relatively healthy gather for a meal and socialization. Where referral is needed for early treatment, the nurse practitioner is the logical member of the health care team to coordinate services. More programs, such as this one on assessment of sensory loss, are needed to acquaint older persons with both the normal and abnormal aspects of aging. Perhaps through education and preventive measures, crippling losses may be minimized along with a decrease in unnecessary institutionalization. There is much work to be done.
- 1. Corso JF: Sensory processes in man during maturity and senescence, in Ordy J. Brizzee KR (eds): Neurobiology of Aging. New York, Plenum Press, 1975, ρ 133.
- 2. Miller D, Slern R: Vision screening and hearing in the elderly. Eye Ear Nose Throat Monthly 53: 130. 1974.
- 3. Corso JF: Sensory processes and age effects in normal adults. J Gerontol 26:90-91. 1971.
- 4. Marmour MF: The eye and vision in the elderly. Geriatr 32:63. 1977.
- 5. Bergman M: Changes in hearing with age. Gerontol 11:148-149. 1971.
- 6. Richards S: Deafness in the elderly. Gerontol Clin 13:350, 1971.