Age-Related Changes in Sensory System PDF

SENSORY SYSTEM AND ELDERLY Pathological processes usually superimpose on physiological aging even in the sensory system including visual, hearing, olfactory, taste and somatosensory functions. TASTE AND SMELL The senses of taste and smell work together. Most tas...

SENSORY SYSTEM AND ELDERLY Pathological processes usually superimpose on physiological aging even in the sensory system including visual, hearing, olfactory, taste and somatosensory functions. TASTE AND SMELL The senses of taste and smell work together. Most tastes are linked with Odors. The sense of smell begins at the nerve endings high in the lining of the nose. There are about 10,000 taste buds. The taste buds’ sense sweet, salty, sour, bitter, and umami Flavors. Umami is a taste linked with foods that contain glutamate, such as the seasoning monosodium glutamate (MSG). Smell and taste play a role in food enjoyment and safety. A delicious meal or pleasant aroma can improve social interaction and enjoyment of life. Smell and taste also allow you to detect danger, such as spoiled food, gases, and smoke. The number of taste buds decreases as person ages. Each remaining taste bud also begins to shrink. Sensitivity to the five tastes often declines after age 60. In addition, your mouth produces less saliva as you age. This can cause dry mouth, which can affect your sense of taste. The sense of smell can also diminish, especially after age 70. This may be related to a loss of nerve endings and less mucus production in the nose. Mucus helps odours stay in the nose long enough to be detected by the nerve endings. It also helps clear odours from the nerve endings. Certain things can speed up the loss of taste and smell. These include diseases, smoking, and exposure to harmful particles in the air. Decreased taste and smell can lessen your interest and enjoyment in eating. You may not be able to sense certain dangers if you cannot smell odours such as natural gas or smoke from a fire. If your senses of taste and smell have diminished, talk to your provider. The following may help: Switch to a different medicine, if the medicine you take is affecting your ability to smell and taste. Use different spices or change the way you prepare food. Buy safety products, such as a gas detector that sounds an alarm you can hear. TOUCH, VIBRATION, AND PAIN The sense of touch makes you aware of pain, temperature, pressure, vibration, and body position. Skin, muscles, tendons, joints, and internal organs have nerve endings (receptors) that detect these sensations. Some receptors give the brain information about the position and condition of internal organs. Brain interprets the type and amount of touch sensation. It also interprets the sensation as pleasant (such as being comfortably warm), unpleasant (such as being very hot), or neutral (such as being aware that one is touching something). With aging, sensations may be reduced or changed. These changes can occur because of decreased blood flow to the nerve endings or to the spinal cord or brain. The spinal cord transmits nerve signals and the brain interprets these signals. Health problems, such as a lack of certain nutrients, can also cause sensation changes. Brain surgery, Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 1 problems in the brain, confusion, and nerve damage from injury or long-term (chronic) diseases such as diabetes can also result in sensation changes. Symptoms of changed sensation vary based on the cause. With decreased temperature sensitivity, it can be hard to tell the difference between cool and cold and hot and warm. This can increase the risk of injury from frostbite, hypothermia (dangerously low body temperature), and burns. Reduced ability to detect vibration, touch, and pressure increases the risk of injuries, including pressure ulcers (skin sores that develop when pressure cuts off blood supply to the area). After age 50, many people have reduced sensitivity to pain. Or you may feel and recognize pain, but it does not bother you. For example, when there is injury, one may not know how severe the injury is because the pain does not trouble the person. One may develop problems walking because of reduced ability to perceive where the body is in relation to the floor. This increases the risk of falling, a common problem for older people. Older people can become more sensitive to light touches because their skin is thinner. The following measures can help one stay safe: Lower the water heater temperature to no higher than 120°F (49°C) to avoid burns. Check the thermometer to decide how to dress, rather than waiting until you feel overheated or chilled. Inspect the skin, especially feet, for injuries. If there is an injury, treat it. DO NOT assume the injury is not serious because the area is not painful. VISION CHANGES IN OLDAGE Just as physical strength decreases with age, eyes also exhibit an age-related decline in performance — particularly as one reaches 60s and beyond. Sensory Dysfunction Functional Impairment Social Isolation Loss of independence Depression Injury Decreased quality of life Eye Examinations Healthy older adults Complete eye examination every year Visual acuity Retina Intraocular pressure (IOP) Some age-related eye changes are gradual, over time can limit functional ability, such as presbyopia (eyes gradually lose the ability to see things clearly up close. It is a normal part of aging. In fact, the word "presbyopia" means "old eye" in Greek), are perfectly normal and don't signify any sort of disease process. While cataracts can be considered an age-related disease, they are extremely common among seniors and can be readily corrected with cataract surgery. Some, however, will experience more serious age-related eye diseases that have greater potential for affecting the quality of life as one grows older. These conditions include glaucoma (a condition of Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 2 increased pressure within the eyeball, causing gradual loss of sight), macular degeneration and diabetic retinopathy. Presbyopia is a perfectly normal loss of focusing ability due to hardening of the lens inside your eye. One can compensate for this gradual decline in focusing ability by holding reading material farther away from your eyes. But eventually reading glasses, progressive lenses or multifocal contact lenses are required. Internal changes Decreased pupil size, decrease retinal illumination Decreased visual acuity (Sharpness of vision) Decreased light sensitivity (difficulty seeing in dim areas/ at night) Dark and light adaptation takes longer Distortion in depth perception Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 2 Lens: Yellowed/ Slightly cloudy (opacification) Increased difficulty in distinguishing between blue green and violet Increased sensitivity to glare Cataracts - Even though cataracts are considered an age-related eye disease, they are so common among seniors that they can also be classified as a normal aging change. Modern cataract surgery is extremely safe and so effective that 100 percent of vision lost to cataract formation usually is restored. If you are noticing vision changes due to cataracts, don’t hesitate to discuss symptoms with your eye doctor. Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 3 Major Age-Related Eye Diseases ∙ Macular degeneration. Also called age-related macular degeneration or AMD, macular degeneration is the leading cause of blindness among seniors. ∙ Glaucoma - risk of developing glaucoma increases with each decade after age 40, from around 1 percent in 40s to up to 12 percent in 80s. ∙ Diabetic retinopathy - 40 percent of elders have some degree of diabetic retinopathy that could lead to permanent vision loss. Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 4 How Aging Affects Other Eye Structures The changes include: Reduced pupil size - As one ages, muscles that control pupil size and reaction to light lose some strength. This causes the pupil to become smaller and less responsive to changes in ambient lighting. Because of these changes, people in their 60s need three times more ambient light for comfortable reading than those in their 20s. Also, seniors are more likely to be dazzled by bright sunlight and glare when emerging from a dimly lit building such as a movie theatre. Eyeglasses with photochromic lenses and anti-reflective coating can help reduce this problem. As one ages, there is loss of some of the visual abilities - Dry eyes - As one ages, our bodies produce fewer tears. This is particularly true for women after menopause. If you begin to experience a burning sensation, stinging, or other eye discomfort related to dry eyes, use artificial tears as needed throughout the day for comfort, or consult eye doctor for other options such as prescription dry eye medications. Loss of peripheral vision - Aging also causes a normal loss of peripheral vision, with the size of our visual field decreasing by approximately one to three degrees per decade of life. By the time one reaches 70s and 80s, a peripheral visual field loss of 20 to 30 degrees is seen. Because the loss of visual field increases the risk for automobile accidents, one has to be careful when driving. To increase the range of vision, elderly need to turn the head and look both ways when approaching intersections. Decreased colour vision - Cells in the retina that are responsible for normal colour vision decline in sensitivity as one ages, causing colours to become less bright and the contrast between different colours to be less noticeable. In particular, blue colours may appear faded or "washed out." While there is no treatment for this normal, age-related loss of colour perception, one should be aware of this loss in one’s profession (e.g. artist, tailor or electrician) who require fine colour discrimination. Vitreous detachment - As one ages, the gel-like vitreous inside the eye begins to liquefy and pull away Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 5 from the retina, causing "spots and floaters" and (sometimes) flashes of light. This condition, called vitreous detachment, is usually harmless. But floaters and flashes of light can also signal the beginning of a detached retina — a serious problem that can cause blindness if not treated immediately. Floaters look like small specks, dots, circles, lines or cobwebs in the field of vision. While they seem to be in front of the eye, they are floating inside. Floaters are tiny clumps of gel or cells inside the vitreous that fills eye. What you see are the shadows these clumps cast on the retina. Flashes can look like flashing lights or lightning streaks in the field of vision. CHANGES IN HEARING The primary function of ears are the following: Hearing Maintaining balance. Hearing occurs after sound vibrations cross the eardrum to the inner ear. The vibrations are changed into nerve signals in the inner ear and are carried to the brain by the auditory nerve. Balance (equilibrium) is controlled in the inner ear. Fluid and small hair in the inner ear stimulate the auditory nerve. This helps the brain maintain balance. As one ages, structures inside the ear start to change and their functions decline. The ability to pick up sounds decreases. One may also have problems maintaining your balance as you sit, stand, and walk. Age-related hearing loss is called presbycusis. It affects both ears equally. Hearing, particularly the ability to hear high-frequency sounds, may decline. Trouble telling the difference between certain sounds. Or may have problems hearing a conversation when there is background noise. If having trouble hearing, discuss the symptoms with health care provider. One way to manage hearing loss is by getting fitted with hearing aids. Persistent, abnormal ear noise (tinnitus) is another common problem in older adults. Causes of tinnitus may include wax buildup, medicines that damage structures inside the ear or mild hearing loss. If the problem of tinnitus is present, ask health care provider how to manage the condition. Impacted ear wax can also cause trouble hearing and is common with age. Compiled by- Ms. Zainab Patharia Faculty at Sir Vithaldas Thackersey College of Home Science. 6