Aging changes in the senses

Aging changes in the senses

Information

As you age, the way your senses (hearing, vision, taste, smell, touch) give you information about the world changes. Your senses become less sharp and you may have trouble telling apart details.

Sensory changes can affect your lifestyle. You may have problems with communicating, enjoying activities, and staying involved with people. Sensory changes can lead to isolation.

Your senses receive information from your environment. This information can be in the form of sound, light, smells, tastes, and touch. This information is converted to nerve signals and carried to the brain. There, it is turned into a meaningful sensation.

A certain amount of stimulation is required before you become aware of a sensation. This minimum level is called the threshold. Aging increases this threshold. So the amount of stimulation needed for you to be aware of the sensation becomes greater.

All senses can be affected by aging, but hearing and vision are most affected. Many of these changes can be offset with equipment such as glasses and hearing aids or by changes in lifestyle.

Hearing

Your ears have two jobs. One is hearing and the other is 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 carried to the brain by the auditory nerve.

Balance (equilibrium) is controlled in the inner ear. Fluid and small hairs in the inner ear stimulate the auditory nerve. This helps the brain to maintain balance.

As you age, structures inside the ear start to change and their functions decline. Your ability to pick up sounds decreases. You may also have problems maintaining your balance as you sit, stand, and walk.

Age-related hearing loss is called presbycusis. It affects both ears. Hearing may decline, especially of high-frequency sounds. You may also have trouble telling apart certain sounds. Or, you may have problems understanding others when there is background noise. If you are having trouble hearing, discuss your symptoms with your health care provider. Ways to manage hearing loss include being fitted with a hearing aid.

Persistent, abnormal ear noise (tinnitus) is another common problem in older adults. Cause of tinnitus may include wax buildup or medicines that are harmful to the structures inside the ear. If you have tinnitus, talk with your health care provider about how to manage the condition.

Impacted ear wax can also cause trouble hearing and is common with increasing age. Impacted ear wax can be removed by your health care provider.

Vision

Vision occurs when light is processed by your eye and interpreted by your brain. Light passes through the transparent eye surface (cornea). It continues through the pupil. This is the opening to the inside of the eye. The pupil becomes larger or smaller to control the amount of light that enters the eye. The colored portion of the eye is called the iris. It is a muscle that controls the pupil size. After light passes through your pupil, it reaches the lens. The lens focuses light on your retina (the back of the eye). The retina converts light energy into a nerve signal that is carried by the optic nerve to the brain where it is interpreted.

All of the eye structures change with aging. The cornea becomes less sensitive, so injuries may not be noticed. By the time you turn 60, your pupils decrease to about one third of the size they were when you were 20. The pupil may react more slowly in response to darkness or bright light. The lens becomes yellowed, less flexible, and slightly cloudy. The fat pads supporting the eyes decrease in amount and the eyes sink into their sockets. The eye muscles become less able to fully rotate the eye.

As you age, the sharpness of your vision (visual acuity) gradually declines. The most common problem is difficulty focusing the eyes on something close. This condition is called called presbyopia. Reading, or bifocal, glasses or contact lenses can help correct presbyopia.

You may be less able to tolerate glare. Glare such as from a shiny floor in a sunlit room can make it difficult to get around indoors. You may have trouble adapting to darkness or bright light. Problems with glare, brightness, and darkness means you may need to give up driving at night.

As you age, it gets harder to tell apart blues and greens than it is to tell apart reds and yellows. Using warm contrasting colors (yellow, orange, and red) in your home can improve your ability to see. Keeping a red light on in darkened rooms, such as the hallway or bathroom, makes it easier to see than using a regular night light.

With aging, the gel-like substance (vitreous) inside your eye starts to shrink. This creates small particles called floaters in your field of vision. In most cases, floaters do not reduce your vision. But if you develop floaters suddenly or have a rapid increase in the number of floaters, you should have your eyes checked by a professional.

Reduced peripheral vision is common in older persons. This can limit activity and ability to interact with others. You may not communicate even with persons sitting next to you because you cannot see them well. Driving can become dangerous.

Weakened eye muscles may not allow you to move your eyes in all directions. Looking upward may be limited. The area in which objects can be seen (visual field) gets smaller.

Aging eyes do not produce enough tears. This leads to dry eyes. Left untreated, infection, inflammation, and scarring of the cornea can occur. Dry eyes can be relieved by using eyedrops or artificial tears solutions.

Common eye disorders in the elderly (changes that are not normal) include cataracts, glaucoma, macular degeneration, and diabetic and hypertensive retinopathy.

If you are having vision problems, discuss your symptoms with your health care provider.

Taste and Smell

The senses of taste and smell work together. Most tastes come from odors. The sense of smell begins at the nerve endings high in the lining of the nose.

You have approximately 9,000 taste buds. Your taste buds are responsible for sensing sweet, salty, sour, and bitter tastes.

Smell and taste play a role in  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 you age. Each remaining taste bud also begins to lose mass (atrophy). Sensitivity to the four tastes often declines after age 60. Usually salty and sweet tastes are lost first, followed by bitter and sour tastes. In addition, your mouth produces less saliva as you age. This causes dry mouth, which can affect your sense of taste.

Sense of smell can diminish, especially after age 70. This may be related to loss of nerve endings in the nose and to less mucus being produced in the nose. Mucus helps odors stay long enough to be detected by the nerve endings. It also helps clear odors 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. Risk of danger is increased because a person cannot smell odors such as natural gas or even smoke from a fire just starting.

If your senses of taste and smell have diminished, talk to your health care provider. There may be help. For example:

  • Some medicines can alter your ability to smell and taste things. Changing your medicine may improve this.
  • Sometimes changes in the way food is prepared, such as using different spices can help.
  • To ensure your safety, look into buying products such as a gas detector that gives off alarms you can see and hear.

Touch, Vibration, and Pain

The sense of touch also includes being 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. Though you may not be aware of this information, it helps to identify changes (for example, the pain of appendicitis).

Your 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 you are touching something).

With aging, you may have reduced or changed sensations. These changes can be related to decreased blood flow to the nerve endings or to the spinal cord or brain. The spinal cord transmits nerve signals and the brain interprets the signals.

Health problems such as lack of certain nutrients can also cause sensation changes. Brain surgery, problems in the brain, confusion, nerve damage from injury or chronic diseases such diabetes can also result in changes in sensation.

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 between hot and warm. This can increase 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. 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 you are injured, you may not know how severe the injury is because the pain does not trouble you.

You may develop problems with walking because of reduced ability to perceive where your body is in relation to the floor. This increases your risk of falling, a common problem for older people.

Older persons can develop an increased sensitivity to light touch because of thinner skin.

If you are having symptoms of changes in touch, pain, or problems standing or walking, talk with your health care provider. There may be ways to manage the symptoms.

The following measures can help you stay safe:

  • Adjust hot water heater temperature to no higher than 125°F (51°C) to avoid burns.
  • Check the thermometer to decide how to dress rather than waiting until you feel overheated or chilled.
  • Inspect your skin, especially your feet, for injuries. If you find an injury, treat it. Do not assume that because an area is not painful, the injury is not significant.

As You Grow Older, You Will Have Other Changes, Including:

References

Caprio TV, Williams TF. Comprehensive geriatric assessment. In: Duthie EH, Katz PR, Malone ML, eds. Practice of Geriatrics. 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap 4.

Hile ES, Studenski SA. Instability and falls. In: Duthie EH, Katz PR, Malone ML, eds. Practice of Geriatrics. 4th ed. Philadelphia, PA: Elsevier Saunders; 2007:chap 17.

Minaker KL. Common clinical sequelae of aging. In: Goldman L, Schafer AI, eds. Goldman’sCecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 24.

Seshamani M, Kashima ML. Special considerations in managing geriatric patients. In: Flint PW, Haughey BH, Lund LJ, et al, eds. Cummings Otolaryngology: Head & Neck Surgery. 5th ed. Philadelphia, PA: Elsevier Mosby; 2010:chap 16.

Review Date:11/10/2012

Reviewed by:David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.

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