The period of later adulthood, defined here as ages 60 through 75 years, is characterized by physical, psychological, and social changes, including both gains and losses. We will examine the multifaceted aspects of successful versus usual versus pathological aging. In examining the changes that occur in later life, researchers often distinguish between primary aging and secondary aging. Usual aging or primary aging refers to gradual, time-related biological processes that are seen as inevitable and universal when comparing young adults to older adults. Some primary physical changes generally associated with later adulthood include a decline in sensory capacity; declines in heart, lung, kidney, and muscle function; and declines in memory. However, within every cohort of older adults, there are those who do not show such declines. These individuals are often considered to be aging “successfully.” Pathological aging or secondary aging refers to the changes that occur as a result of particular conditions or illnesses. The changes that occur because of secondary aging tend to be more common in older ages but are caused more by health habits, heredity, and other influences that vary by person. Some secondary aging processes include heart disease, cancer, dementia, and arthritis.
Physical Changes In Late Adulthood
Changes in appearance include both primary and secondary aging. For instance, skin becomes dryer, thinner, and less elastic in older age (primary aging); however, the rate of these changes may depend on sun exposure, lifelong nutrition, and genetics (secondary aging). Dark patches of skin, called age spots, become more apparent in the transition to older adulthood.
Sensory changes are also common with aging. As the average person ages, the lens of the eye becomes harder and less flexible, resulting in a decreased ability to view objects that are close to the eye. Many older adults require eyeglasses to correct for these changes. In addition, the lens also becomes yellowed with age, which results in a change in the quality of light that is absorbed. One consequence of this is glare. Older pupils are smaller than young pupils in the same light. Both of these changes affect the eye’s ability to adapt to changing light conditions that make night driving more difficult for older adults. There are those eyes, however, that age successfully and never show these types of declines.
Three of the most common diseases of the aging eye are cataracts, glaucoma, and macular degeneration. Cataracts are an extreme condition of lens opacity and are usually correctable with a simple operation to remove the faulty lens and replace it with an artificial lens. Glaucoma involves increasing pressure and atrophy of the optic nerve, which yields abnormalities in the visual field. Macular degeneration involves deterioration of the retina and is a leading cause of blindness in older adults.
Sharp increases in hearing difficulties often start around age 60. About 33% of people older than 70 years report some type of hearing loss. Hearing problems involve the loss of hair cells in the cochlea and disturbances of the inner-ear metabolism. Older adults generally have the most trouble hearing under what are called “masked conditions,” when sounds are obscured or rendered inaudible by other sounds.
The probability of disease increases considerably after the age of 60. In the United States, people older than 65 years account for 33% of the nation’s health care expenditures while only representing 12% of the population. Common chronic conditions of later adulthood include arthritis, heart problems, and high blood pressure. In people older than 65 years, heart disease accounts for almost 40% of all deaths, whereas cancer accounts for an additional 25%. Neither heart disease nor cancer is an inevitable consequence of aging. Both environmental or lifestyle factors, such as smoking, and genetic factors, such as family history, increase the likelihood that people in later life will develop these diseases. Nevertheless, many of the conditions that are associated with aging can be prevented or remediated with adaptive lifestyles, including good nutrition and exercise.
Psychological Functioning In Late Adulthood
Our exploration of the psychological changes that occur with aging will include cognition, mental health, personality, and beliefs. The continued potential for growth and the possibility of decline exists in each of these areas. Cognitive changes in late adulthood are multifaceted. At one end of the spectrum, in later adulthood, we have more experiences and therefore more knowledge with which to face the challenges of daily life. At the other end of the spectrum, we are faced with declines in reasoning, speed of processing, and memory that are often concomitant with the primary physiological changes that occur.
Short-term memory refers to information stored for relatively brief periods of time (<60 seconds). Studies have shown that with usual and successful aging, there is very little decline in late adulthood in short-term memory. However, considerable age-related changes are found on working memory tasks, which involve the active manipulation of different pieces of information in short-term memory. Older adults are more likely than younger and middle-aged adults to experience difficulty holding several items of new information in mind while also trying to analyze and manipulate that information. Long-term memory deficits have also been shown to increase in later adulthood. Older adults seem to have more difficulty on episodic memory tasks such as remembering word lists and text recall. It has, however, been consistently shown that some of these deficits can be remediated by techniques such as training in strategy use and learning.
Dementias are secondary aging processes, which involve a pathological loss of brain functioning in any of the following areas: language, memory, visuospatial skills, emotion or personality, and cognition. Types of dementias include Alzheimer’s disease, Parkinson’s disease, multi-infarct dementia, and cortical-subcortical atrophies. The incidence of dementias increases with age. The most common form of dementia is Alzheimer’s disease, which is characterized by a progressive deterioration of intellect, memory, and personality. Certain abnormalities in the cerebral cortex, called plaques and tangles, are markers for the disease. As with all of the dementias, Alzheimer’s disease is not part of normal aging; however, the incidence of Alzheimer’s disease does increase progressively with age. Current findings suggest that about 3% of the population older than 65 years has Alzheimer’s disease. Several studies have shown that the occurrence of Alzheimer’s disease doubles every 5 years starting at age 65. Multi-infarct dementia is characterized by an irregular, yet progressive, loss of intellectual functioning. The cause of multi-infarct dementia are multiple mini-strokes, in which brief obstructions in the blood vessels of the brain prevent adequate blood flow from reaching different parts of the brain. Finally, subcortical dementias involve the progressive changes to the motor region of the brain, which results initially in losses in motor abilities but eventually often produce cognitive impairment in the late stages. Examples of subcortical dementias include Parkinson’s disease, Huntington’s disease, and multiple sclerosis.
Another related area of interest in the psychological development in late adulthood is the changes and continuities associated with control beliefs. Control beliefs are a two-part construct encompassing both beliefs about one’s abilities to bring about outcomes and beliefs about the role of external factors on outcomes. Older adults tend to believe that age-related declines in memory performance are inevitable, which may in turn influence memory performance. Beliefs about control over one’s health also may become more important in later life because of the impact of such beliefs on health care–seeking behavior and treatment adherence.
The research findings on personality across the life span are ambiguous. Some researchers have suggested that personality traits remain stable across the life span, whereas others have suggested that personality traits may vary significantly across the life span. Several variables (age, gender, martial status) have been shown to be important in individual differences in personality change in older adulthood.
Specific psychological problems, such as anxiety and depression, have not been shown to increase in late adulthood. Clinical depression is defined by the presence of several symptoms, including either depressed mood or loss of interest in nearly all activities over a period of at least 2 weeks, significant weight loss or gain, sleep difficulties, fatigue, and psychomotor slowing; whereas mild depression involves fewer symptoms and less impairment. In the past, clinical depression was often thought of as a major problem of advanced age, but there has been little support for this claim. Several studies have shown the rate of depression in adults older than 65 years was significantly lower than for younger adults. Older adults may, however, be at greater risk for mild depression. Some risk factors for late life depression are bereavement, insomnia, chronic health problems, and prior depression. Anxiety disorders, such as panic attacks, phobias, and generalized anxiety disorder, are actually more common than depression in older adults. As with depression, anxiety is often associated with a variety of medical conditions, such as hypertension, dementias, and heart problems. Risk factors for late-life anxiety disorders include sensory problems, spousal bereavement, and high neuroticism.
Changes in sleep patterns are common in later adulthood. Sleep apnea, heartburn, and periodic leg movements are some of the major causes of significant sleep disturbances in old age. In addition, quality of sleep is reduced by many conditions that affect brain function, including heart disease, dementias, and arthritis. As we discussed earlier, these conditions become more frequent with advancing age, thereby increasing the likelihood of impaired sleep in late adulthood, which can in turn affect cognitive functioning.
Social Factors In Late Adulthood
There are a variety of social changes that may occur as we enter late life, including change in work status or loss of spouse and other significant others. In most industrialized countries, the age of retirement has been decreasing over the past few decades. Research on retirement has shown that older adults who retire or go to part-time work adjust very well to this change, with some even showing improvement in health and well-being. With retirement come significant changes in time and type of leisure activities, such as continuing education and volunteering. Retirement also brings a shifting of roles within the home and social system.
Many older adults are in long-term marriages. The best predictor of the nature of these relationships in later life is the nature of the relationship in earlier life. This means that although there are often fluctuations, the nature of relationships tends to be fairly stable over time. Because the probability of death increases with age, becoming widowed or losing other loved ones is an inevitable part of late adulthood. Adjustment to bereavement is therefore often an important part of this time period. Research has shown that social support and emotional stability are important to bereavement recovery. Family and friends typically play an important supportive role in later life. It is not necessarily the number of people in one’s social network, but the quality of the relationships that makes a difference. In later life, those who have good social support networks, with low social strain, typically show greater psychological and physical well-being.
What is successful aging and what is pathological aging are questions that continue to prove a challenge to scientists and lay people around the world. With the population of the world living longer, late adulthood is an important area of research and exploration. In every area of late-life development, there are important improvements, continuities, and declines. Continued research and development will allow us to understand the mechanisms and processes to understand biological, psychological, and social aging. Although we have focused on the period of later life between ages 60 and 75, it is important to note that there is much variability in the timing and extent of gains and losses during this time period. Moreover, the transition to the “old-old” period, which is usually considered to begin between 75 and 80 years of age, is also marked by large inter-individual differences in functioning.
- Alzheimer’s Association, http://www.alz.org/
- American Association of Retired Persons (AARP), http://www.aarp.org/
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