SENSORY AGING
In studying the changes that occur in the sensory system as we age, it is important to keep in mind that many of these changes are person and context specific - there may be some situations where no problem is noted and others were severe problems seem to occur; are influenced by considerations of both primary and secondary aging; finally impairing problems are seen only in the old-old; most older adults seem to adjust to minor changes capably
Vision
Main findings (Lighthouse for the Blind):
2) rates of vision impairment rise dramatically in advanced old age;
vision problems affect: 1/7 middle-age/young adults; 1/4 of old-old (75+)
3) the most vulnerable elderly are at higher risk; they
most likely and most severe in: females, those living alone, in poverty, with low-education, non-white, poor or only fair health
4) the impairments are highly visible, touching the lives of most middle age and older adults
5) vision impairments are generally misunderstood
Loss of visual acuity (loss of distance vision) increases with age, but is most often correctable with glasses
Presbyopia - difficulty focusing on object close up; noticeable in one’s 40s but progresses from childhood; often "correctable" with bifocals
Other changes:
By age 70 - the cornea becomes rigid and develops a gray band, reducing one’s field of vision
Lens grows cloudier (affects sensitivity to glare and ability to distinguish colors esp. blue-green distinctions because the cloudiness has a yellowish tinge); extreme clouding = cataract; also the lens continues to build cells which accumulate and make the lens more difficult to shape (bulging outward to view near objects, flattening to view far ones) à presbyopia
Deterioration also occurs in the neuronal part of the visual system (decrease of rods and cones, loss of neurons in the optic nerve and visual cortex)
Results from the Berlin Aging Study showed that vision impairments were highly correlated with intelligence measures and with disability (bathing, grooming), so their importance should not be underestimated
Still, about 75% of older adults report no serious impairment with vision, even in those over 75
Hearing
Hearing problems affect 20-25% of those between 45 and 54, but 75% of those between 75-79 years. As much as 15% of those over 65 are legally deaf. Estimates may be on the low side, however, as people are often reluctant to admit hearing problems.
Two main problems with age -
Presbycusis (loss of detection of higher pitched sounds) — begins to appear in our 30s
Tinnitus (ringing in the ears): affects 11% of those between 65 -74 years
Changes to the auditory system with age
Atrophy or destruction of hair cells in the cochlea are most responsible for presbycusis — hair cells associated with the detection of high-pitched sounds are at the base of the cochlea; their loss affects the ability to attend to normal conversation
Also a secondary aging component: exposure to loud noises - males typically have great hearing loss than females (due to jobs); also the rate of hearing loss has increased by 25% between 1971 and 1991
Some changes in the central nervous system, too, those these are less identifiable
Other changes: build up of wax in the ear canal (more common); bones in the middle ear may fuse causing hearing loss at all pitches (less common)
Hearing loss is often associated with social withdrawal and therefore it is important to treat
interventions: hearing aids, though they often amplify all sounds when it is only the higher pitched ones that need to be heard; others - assistive listening devices, providing visual signals rather than auditory ones (e.g., closed captioning), protecting our hearing
Taste and smell
there is a loss of receptors for each sense, but the loss of the sense of smell may be more responsible for older adults’ lack of interest in eating or in eating highly spiced foods
for taste, by one’s late 50s many people notice that they have lost some of their sense of taste; dental problems may also interfere with eating; for smell, one study indicated that as many as 30% of people over age 65 would not be able to detect a gas odor at low levels
taken together these losses can affect diet and nutrition: not eating, eating spoiled or contaminated food, eating less healthful food, etc.
MOTOR PERFORMANCE
Reaction time
Choice reaction time (complex task) is more severely affected than simple reaction time
Reaction time has two components: the detection and perception of the signal and then the preparation of a motor response (thinking) and the production of a motor response (acting)
The thinking phase seems most affected by age; implicates changes in the central nervous system and suggests the concept of general slowing
there is variation among people and among tasks — in work-related settings, there are some occupations where fast reaction times are required (e.g., air traffic controllers whose mandatory retirement age is 55) and others where it is not (university professors, where mandatory retirement may be age 70)
The Musculoskeletal System
impairments in lower body movement are the number one risk factor for nursing home placement
Muscles
Muscle strength tends to decline beginning in one’s 40s with accelerated loss after age 70; greatest loss in fast twitch muscles in the legs — this atrophy cannot be replaced by new muscle mass, but can be decelerated
Bones
Bone density begins decreasing in one’s 40s; most severe for women and may lead to osteoporosis which affects 50 -80% of women over age 65; may make one prone to fractures which are a major cause for loss of independence and admission to a nursing home
Joints
Osteoarthritis - top-ranking chronic condition in older adults; caused by the gradual wearing away of the connective tissue between bones
Effects and interventions
Driving
Elderly drivers are many (around 28% of all drivers currently, 39% by the year 2050) and will increase in future years due to :
Elderly drivers suffer from normal deterioration of physical and physiological abilities. These changes begin to have an effect around age 55, and get much worse after about the age of 75.
Older adults are especially prone to intersection accidents or other accidents including: changing lanes, merging into traffic, and leaving from a parking position. The number 1 traffic violation committed by drivers aged 50 and over is failure to observe right-of-way. The number 2 traffic violation committed by drivers aged 50 and over is improper left turn.
Potential solutions are to:
Housing
person/environment congruence is the strategy where we design the world to fit with a person’s capabilities, allowing independence without overdependence --> promotes healthy aging in place
Americans with Disabilities Act (1990) requires that accommodations be made in all new public buildings for access to those with physical, visual, or hearing impairments. Modifications of existing structures is determined on an affordability basis. However, the needs of older adults (especially the old-old) are often not taken into account when designing or redesigning buildings.
Some newly designed senior residences take such needs into account, but very few can afford such places. The homes of older adults are often not modified, but their familiarity may help compensate for a decreased ability to navigate one’s surroundings.