Spinal cord injury (SCI) can change a person's life instantaneously. Within the first few years following such an injury, various degrees of neurologic recovery may occur, followed by a prolonged period of apparent stability. Recent experience has demonstrated that life expectancy in the more recent decades has improved for people with SCI (1). However, as these individuals age, they are increasingly likely to experience changes in their once-stable health and functional abilities. Therefore, it is important that clinicians understand the theoretic and practical issues of human aging to better address the consequences of aging in this unique population.
This chapter describes many of the processes associated with aging in people with SCI. Various aging theories are reviewed, followed by body system-by-body system discussions of how aging in SCI has an impact on both physical and psychosocial health, now and in the future.
AGING THEORY
Significant to an understanding of aging is the underlying finding that all biologic systems decline constantly as a result of cell death (2). This can occur through various mechanisms, and has been described from numerous theoretical foundations, such as cellular, genetic, endocrine, neurologic, immunologic, and metabolic theories. These theories overlap substantially; however, the underlying messages is that limited internal resources or limited defenses exist against external forces that eventually lead to decline and ultimate death of an organism (3).
Recently, there has been wider acceptance of free-radical theory of aging, which hypothesizes that radicals are produced during normal metabolism and subsequently react with biologic molecules. The degree which these reactions may contribute to cell damage to pathology and senescence is yet to be determined.
The biological theories of aging that address intrinsic or organism issues tend to ignore or minimize the extrinsic or environmental stresses on individuals. These stressors are often accounted for in theories addressing “wear and tear.” Following in this line of theories, it is suggested that aging is caused by some kind of wear or damage to the various body structures, either through use, or by injuries to the genetic mechanisms. Therefore, it can be suggested that a person with SCI may age more quickly because of the added stresses that cause some body systems to be pushed beyond their abilities to repair themselves. This may be seen in tissues that experience heavy or unusual use, such as the genitourinary tract or the shoulders. For example, the function of lower urinary tract has been noted to decline with aging in terms of bladder capacity, the ability to postpone voiding, urethral and bladder compliance, and an increase in involuntary bladder contractions (6). In the individual with SCI, these lower urinary tract changes may occur at earlier ages than typically seen with the aging process, as the result of years of trauma to the urethra through catheterization, bladder hypertrophy caused by chronic sphincter-detrusor dyssynergia, and chronic infections. These factors, in addition to aging, may necessitate modifications to a previously effective program of urinary management. In another example, in people using wheelchairs, the upper extremities are used in a manner that is unusual, and can, with time, result in shoulder deterioration and pain. These examples typify one of the main issues with aging in SCI: that is, the actual wear and tear on an aging body structure may result in significant functional consequences for the person with SCI.
In the following sections, many of the aging-related changes experienced by people with SCI are described. The extent to which these changes have an impact on both physical and psychosocial function and health is also discussed.
THE GENITOURINARY SYSTEM
Diminished bladder capacity and urethral compliance, an increase in uninhibited detrusor contractions and residual bladder volumes, as well as a gradual decline in kidney function are some of the findings associated with normal human aging in the general population (7,8). In addition, age-related changes in the diurnal output of urine result in an increase in nocturia. Another finding is that elderly individuals appear to be at increased risk for urinary tract infections (UTIs), presumably related to the decline in immune function, postmenopausal changes, and the effects of prostatism (9).
Following SCI, the physiological disruption of genitourinary function is characterized by the loss of volitional control over micturition as well as the loss of coordination of detrusor and sphincter reflexes. Once these reflexes have recovered, there is a tendency to sphincter-detrusor dyssynergia and elevated lower urinary tract pressure over time. This can lead, ultimately, to hypertyophy of the detrusor muscle and decreased bladder compliance. The cumulative effect of these changes can also result in the development of hydronephrosis and upper tract deterioration (9).
Although these SCI-related alterations in urinary tract physiology pose significant risks to health, urinary tract complications have been declining as a cause of death in SCI over the past 25 years, now accounting for only 2.3 percent of deaths (10). The improved urinary tract-related mortality is likely due to clinical advances in urologic management and modern antibiotic treatment. It is important, however, to note that urologic complications continue to be common among people living with SCI. Data from the U.S. Spinal Cord Injury Model Systems show that the incidence of abnormal renal function testing increases with both age and duration of injury, and that removal of urinary tract stones, most common in persons using indwelling catheters, increased from 3.1 percent at 5 years to 10.8 percent at 20 years post-injury.
The method of bladder management appears to be associated with certain urinary complications. Typically, studies have documented higher rates of bladder stones, UTIs, and bladder cancer associated with the use of indwelling cithers. For individuals who are managed with an indwelling catheters, anticholinergic medication used routinely may improve health outcomes (11). Individuals using long-term intermittent catheterization may be at an increased risk for developing urethral stricture and epididymitis (12).
Cancer of the bladder appears to be one of the few neoplasms for which the incidence is unequivocally increased by the presence of SCI (13-16). Risk factors for the development of bladder cancer that are related to SCI include recurrent UTI as well as the use of indwelling catheters (17,18). It appears that malignant degeneration requires the cumulative effects of exposure to various risk factors (such as recurrent infections, indwelling catheter management, urinary tract stones, cigarette smoking, etc.) over a long period of time. A recent study showed that indwelling catheter management resulted in a four-fold higher risk for the development of bladder cancer than nonindwelling catheter methods of management (17). People with SCI who develop bladder carcinoma typically present with hematuria. Unfortunately, hematuria is not a reliable indicator of bladder cancer in people with SCI, because it also commonly occurs with UTI, bladder stones, and catheter changes.
These tumors are commonly metastatic and invasive at the time of diagnosis in people with SCI, highlighting the importance of developing effective screening methods. Urine cytology and biochemical markers of urinary tract malignancy do not appear to be appropriate screening tools at present, because of their high false-positive rate, which can be caused by concomitant UTI and related hematuria. Although the effectiveness of screening cystoscopy to detect these tumors in chronically catherized spinal cord individuals has been questioned by some, most clinicians feel that this method remains the best option for early detection of bladder cancer in persons with SCI (18,19). In addition, because of the risk of chronic prostatitis related to recurrent UTI, it is reasonable to speculate that there may be some added risk of prostate cancer in males with chronic SCI, although there is no evidence to date that such an association exists. In fact, one recent study found a lower incidence of carcinoma of the prostate in those spinal cord injured individuals who were more disabled, suggesting that, at the very least, there is no added risk of this cancer associated with SCI (20). Nonetheless, males aging with SCI should be considered at risk and be provided with the age-specific prostate cancer screening that is recommended for their general population counterparts (21).
Guided by an awareness of these issues, the long-term follow-up for people with SCI should include attention to the potential for functional deterioration and the development of urinary tract cancers. The clinical approach is based on prevention and early detection. The person with SCI should be educated regarding the fundamentals of bladder management in an effort to reduce the risk of recurrent UTI. This includes education regarding adequate hydration, hygienic bladder management technique, and regular urologic follow-up. Individuals who elect to use indwelling catheter methods of bladder management should receive adequate information regarding the accompanying risk of bladder cancer. Cigarette smoking has also been identified as a significant risk factor for bladder cancer, therefore, smoking cessation programs should also be encouraged for those who smoke.
THE GASTROINTESTINAL SYSTEM
Several studies have described the consequences of aging on gastrointestinal physiology in the general population (22-24), showing that a generalized decline in gut motility and diminished acid secretion accompanies the aging process. Acid secretion in the stomach is also diminished with increasing years, and the stomach exhibits diminished emptying of fluid meals but relatively unimpaired emptying of solid food. The small bowel shows little, if any, specific change related to aging; however, the colon and rectum exhibit diminished motility and an increase in diverticular disease (25). Surveys of people with SCI have documented a variety of gastrointestinal complications and functional changes that accompany the aging process.
In the gastrointestinal system, colorectal function is significantly altered by SCI and would be expected to be a substantial source of problems in the person aging with SCI. It is known that colonic transit time is prolonged in persons with spinal cord injury, especially in the left colon and rectum (26,27). This finding correlates with the common report of constipation in this population. Specifically, a British study of persons more than 20 years post-injury showed that 42 percent of the subjects had difficulties with constipation, whereas 27 percent reported problems with fecal incontinence, and 35 percent had gastrointestinal pain (28,29). Those with tetraplegia were more likely to report fecal incontinence, whereas constipation was more likely to be reported by people with paraplegia and those who used digital stimulation, manual evacuation, or valsalva for their bowel routines.
The most profound alteration in gastrointestinal physiology resulting from SCI is the loss of volitional control over bowel emptying. This requires the adoption of an individualized bowel evacuation regimen that incorporates a variety of reflex stimulation maneuvers, laxatives, and dietary interventions. It is believed that constipation manifested by difficulties in producing reflex bowel evacuation is commonly the result of the anorectal dyssynergia or inadequate rectal expulsive force caused by SCI gut motility impairment (27). The primary treatment approach is based on an assessment of the existing bowel routine, with suggestions for alterations based on common sense. Many people with SCI have chosen excessively long intervals between bowel programs for the convenience. They should be encouraged to maintain a bowel program frequency of daily or every other day. The use of laxatives or enemas should be avoided or kept to a minimum. Suppository use is considered supplemental to digital stimulation and evacuation when necessary. For some individuals with refractory bowel dysfunction characterized by excessively long bowel programs or frequent fecal incontinence, opting for an elective colostomy may significantly improve quality of life #ref.
Hemorrhoids and periodic rectal bleeding are also common accompaniments to chronic SCI, with a majority of individuals reporting these conditions (32). For minor symptomatic lesions, topical therapy may be sufficient. For more severe hemorrhoids, banding is commonly required. In the most severe refractory cases presenting with abundant hemorrhoid tissue and recurrent significant bleeding, operative hemorrhoidectomy may be necessary.
No evidence exists to date to suggest that persons with SCI are at added risk of colon cancer. However, it is safe to assume that this population is at risk equal to the general population for this common cancer. For that reason, periodic SCI follow-up should include screening for colorectal cancer (33). Fecal occult blood may not be a reliable screening tool because of the frequent presence of hemorrhoids, rectal prolapsed and other distal rectal pathology in the SCI population. Therefore, people with SCI in the at-risk age group should be endoscopically screened periodically. The endoscopist should be familiar with the risk of autonomic dysreflexia and be prepared to treat blood pressure elevation or other sequelae during the procedure.
There has been speculation about an increased incidence of gastroesophageal reflux disease (GERD) in people with SCI. However, a recent report showed no significant difference in the overall incidence of reflux disease but a higher prevalence of more severe esophagitis in the SCI subjects (34). It has been suggested that changes in gastric motility may be implicated in chronic abdominal distention in long-term SCI, but the underlying cause of gastric dilatation remains poorly understood (33). Recent evidence suggests that gallstone disease is approximately seven times more prevalent in the SCI population than in the general population, having been found at autopsy in 29 percent of a group of spinal cord injured subjects compared to a 4 percent incidence in nondisabled matched controls (35). It does not appear that the formation of gallstones in SCI is specifically related to aging as the added risk of gallstone disease appears to be restricted to individuals with lesions above T10, with the increased incidence of stones generally occurring within the first year post-injury. Nonetheless, clinicians should be aware of the increased incidence of this condition with age in general when evaluating abdominal complaints in long-term follow-up population. In addition, although research has demonstrated an increased risk for the development of gallstones in people with SCI, the risk of biliary complications was not of sufficient magnitude in this group to warranty prophylactic cholecystecomy (36).
Because of the high frequency of gastrointestinal problems in the aging SCI population, specific attention to bowel symptoms should be incorporated into routine follow-up procedures. Regular assessment of the bowel program should be done, and ongoing education regarding bowel program performance, ways to manage and/or modify the bowel routine, and a bowel-friendly diet should be emphasized.
THE INTEGUMENT
Multiple factors result in the aging of human skin. Normal aging results in atrophy and changes in the histologic structures that comprise the dermis (37). Elasticity and vascularity of the dermis, and collagen content are diminished, predisposing aging skin to injury. Flattening of the dermal-epidermal junction and thinning of the epidermis result in a decreased tolerance to shear and a greater likelihood of epidermal detachment and blister formation. Diminished vascularity and sweating also may heighten the risk of thermal injury. People with SCI are known to be at risk for skin trauma resulting in pressure ulcers, commonly related to immobility, lack of sensory protection, and spasticity.
Data from the United States Model Spinal Cord Injury Systems showed the incidence of pressure ulcers increasing from 15 percent at 1-year following SCI to nearly 30 percent at 20 year post-injury (38). The risk is highest in those with complete tetraplegia, who demonstrated a 40 percent prevalence of pressure ulcers at the 20-year follow-up. The basic principles of pressure relief, debridement, and asepsis are still the foundation of successful conservative management (39). Large and deep skin sores will commonly require myocutaneous flap closure . Local infection necessitates treatment with appropriate antibiotics, and deep wounds should raise the suspicion of contiguous osteomyelitis. In these instances, a bone biopsy should be performed for the purposes of diagnosis and identification of the causative organisms, to guide antibiotic therapy.
Chronic open skin sores of long duration have been associated with the development of Marjolin's ulcer, and the development of squamous carcinoma in the sore (39). Because of the high frequency of skin sore occurrence in the chronic SCI population, periodic assessment should include a thorough evaluation of the integument and a reinforcement of skin sore prevention education. The clinical approach to managing skin sores in SCI is primarily prevention through patient education. This involves instruction on skin protection, pressure relief, hygiene, and routine surveillance. If initiated promptly and performed diligently, conservative treatment of pressure sores is commonly effective.
THE NERVOUS SYSTEM
Changes related to the nervous system in the aging general population have been reported to include loss of vibratory sensation, muscle mass, and strength; slower reaction time, decreased fine coordination and agility, decreased deep tendon reflexes, and deteriorating stability in station and gait (40). The aging spinal cord histologically shows loss of myelinated tracts as well as a loss of anterior horn cells. However, significant changes may not occur until after the fifth decade (41). A study of persons aging with SCI of more than 20 years duration showed that 12 percent reported some sensory loss, and more than one in five individuals reported increasing motor deficits over the years (42). Without further study, it is not possible to state with certainty that an age-related loss of myelinated tracts and dropout of anterior horn cells may contribute to these reported symptoms.
In studies of people with long-term SCI, a high incidence of upper extremity entrapment neuropathies has been reported, with up to 63 percent of people with paraplegia showing evidence of these, both on electrodiagnostic testing and on symptom surveys (43,44). The most frequent site of involvement is the median nerve at the wrist, but ulnar nerve entrapments at the elbow and wrist are also common. Because of repeated hand contact with wheelchair rims, as well as positioning of the wrist during transfer activities and pressure relief, individuals with SCI are clearly at risk for nerve entrapments in the upper extremities. It is suspected that the incidence of significant entrapment increases with duration of injury, although this has not been conclusively proven. Treatment for this condition should include assessing the mechanics of mobility and daily living activities to determine any underlying sources of repetitive trauma. For some individuals, the resolution of symptoms may necessitate a modification of activities. In addition, education regarding techniques to conserve and protect wrist function may be beneficial for some individuals. Other modalities include wrist splinting to reduce repetitive trauma at the extremes of wrist flexion and extension, which are known to contribute to carpal tunnel symptomatology. Although corticosteroid injection therapy has been tried as a conservative measure for people with carpal tunnel syndrome, the benefit may be only temporary. Although ulnar entrapments at the wrist may prompt consideration of surgical treatment, SCI survivors with those neuropathies are usually successfully treated with activity and equipment modification and rarely require surgical intervention. However, when conservative measures fail to provide a relief of symptoms in people with significant entrapments, surgical release of the transverse carpal ligament is often recommended. Individuals undergoing this surgery should anticipate a period of restricted activity after the surgery, which may temporarily necessitate an increased need for assistance from others. Postoperative activity restrictions have been reduced with some recent advances in surgical technique, including the percutaneous endoscopic approach to transverse carpal ligament section.
When individuals with chronic SCI experience neurologic deterioration, it is most commonly the result of progressive posttraumatic cystic myelopathy (45). This condition is also referred to as posttraumatic syringomyelia, and is characterized by the progressive enlargement of a cystic cavity originating at the site of injury and extending in either a cephalad or caudal direction in the spinal cord. More recently, the concept of progressive cystic myelopathy has been broadened to include progressive noncystic or myelomalacic myelopathies. These conditions are thought to be a part of the pathophysiologic continuum. The onset of this neurologic complication may vary from several months to several decades after injury, but most commonly occurs within the first 5 to 10 years post-injury.
Signs and symptoms of late progressive neurologic deterioration include
Confirmation of this diagnosis includes a combination of the typical history and physical findings of magnetic resonance imaging (MRI) of an abnormality of an enlarging syrinx cavity or myelomalacic spinal cord. Arachnoid scarring that interferes with spinal fluid flow and spinal cord mobility appears to be the underlying mechanism of progressive spinal cord pathology. When neurologic deterioration is progressive, surgical treatment, including untethering of the arachnoid scar and, in some cases, the shunting of cyst cavity fluid, is warranted (46). All individuals with SCI have the potential for late neurologic change; therefore, the assessment of motor and sensory function, as well as a neurologic review of the systems, should be included in periodic follow-up. Appropriate electrodiagnostic and imaging studies are indicated in the presence of signs or symptoms of neurologic deterioration (46,47).
THE MUSCULOSKELETAL SYSTEM
In the general population, musculoskeletal system aging is characterized by the deterioration of articular cartilage function. This ultimately leads to degenerative arthritic changes, both in the spine and in joints of the appendicular skeleton (48). Because of the unique physical stresses required in people with SCI during mobility activities, it is not surprising that overuse syndromes of the upper extremities are common in this population.
More than 50 percent of SCI survivors have been shown to report upper extremity pain (49,50), with shoulder discomfort being the most frequent complaint, followed by pain at the wrist. Transfer activities, wheelchair propulsion, and pressure relief maneuvers most commonly produce upper extremity discomfort. Although acromioclavicular degenerative changes may be seen on X-ray, plain radiographs commonly are of limited value in assessing shoulder pain in these individuals. In symptomatic individuals with SCI who report shoulder pain, arthrography and MRI imaging have better diagnostic yield, commonly showing impingement syndrome and rotator cuff tears (51,52).
Most studies demonstrate that the prevalence and severity of upper extremity overuse problems are correlated with both age and duration of injury. These problems can be managed conservatively, including a periodic review of daily activities and mobility mechanics, which may result in suggestions for activity modification in an effort to avoid pain-causing maneuvers. Individuals with overuse syndrome at the shoulders may have a muscular imbalance across the glenohumeral joint, with anterior musculature development significantly greater than that posterior to the shoulder. Muscular balance across the joint to restore optimal glenohumeral geometric relationships may be facilitated with an exercise regimen specifically designed to address the posterior shoulder girdle (53). Surgery for impingement or rotator cuff tears has been suggested when conservative measures are unsuccessful. Individuals with SCI who contemplate operative treatment for impingement or rotator cuff tears should anticipate a prolonged and possibly difficult postoperative rehabilitation period as well as a temporary impact on independence, with additional personal care assistance commonly required (54,55).
Osteoporosis is a common accompaniment to the aging process, most typically associated with post-menopausal elderly women but also occurring in aging men (56). Osteoporosis caused by paralysis and disuse is commonly felt to be the underlying risk factor for pathologic fractures following SCI. Lower extremity osteoporosis develops rapidly in the first year post-injury, with about one-third of the original bone mass being lost by 16 months post-injury before relative stability is achieved (57). An extremity fracture rate of over 30 percent for individuals followed for several decades has been reported in recent surveys (58). In addition, data from the U.S. Model Spinal Cord Injury Systems indicate that women are more likely to develop long bone fractures in the lower extremities as the time post-injury increases (38). Various interventions have been proposed, including standing, functional electrical stimulation (FES), and treatment with biphosphonates. However, no treatment has yet been shown to provide long-term prevention of osteoporosis and protection from fracture risk. Preliminary trials of pamidronate have shown some promise, and it is hoped that continued investigation in this area will lead to effective treatment in the future (59). SCI clinicians should incorporate a thorough symptom review and examination as a part of periodic reassessment to identify musculoskeletal complaints at their earliest onset. In addition, equipment and seating system interventions may improve the suboptimal posture that often results in chronic back pain (48).
THE IMMUNE SYSTEM
The normal immune system declines with age, and the risk of infection increases, according to research (60-62). In addition, the function of the immune system is known to be influenced by factors such as depression, deterioration of social support systems, chronic pain, neuroendocrine changes, and the influence of medications (63).
There is evidence of a diminished immune function in people with SCI above the T10 level, which is manifest by impaired bacterial phagocytosis (64). A longitudinal study of people with SCI of more than 20 years duration showed a dramatic increase in urinary tract infections (UTIs) among those aged 60 and over, and a slight increase in the frequency of infection between the tenth and thirtieth post-injury year (28). Because factors such as depression, diminished psychosocial support, polypharmacy, and chronic pain may coexist in people with SCI, it would appear safe to assume that those aging individuals will have an increased likelihood of immune impairment when compared to their nondisabled counterparts.
Several recent studies have suggested that exercise and rehabilitation therapies are associated with improved cellular immunity in persons with SCI (65,66). It is hoped that further research in immunology, immunologic assessment, and treatment will result in interventions designed to improve immune defenses in people with chronic SCI.
PSYCHOSOCIAL ASPECTS OF SCI AND AGING
Unlike many of the physical changes associated with aging, it has not been the case that some psychosocial aspects of a person's life necessarily decline. In fact, some may actually improve. When potential difficulties in these areas do occur, early identification and intervention can delay, minimize, or even eliminate the negative consequences of age-related changes. Unfortunately, such interventions may be difficult to implement with any degree of certainty as to effectiveness, and efforts in identifying effective strategies may be hampered by misperceptions of older individuals and their quality of life. It has been asserted, in fact, that ageism still has a detrimental effect on healthy aging (67). A further consideration is that the same interventions that are found to be effective in the general population may be inappropriate or ineffective for individuals aging with SCI.
Independence
Aging individuals may experience a loss of muscle strength, slowed reflexes, decreased coordination, lower energy levels, chronic pain, arthritis, and osteoporosis, which can result in declining physical independence (68,69). Data from the 1996 National Health Interview Survey showed that more than 22 percent of the civilian community-dwelling population of the United States, aged 45 to 64 years and more than 36 percent of those aged 65 and older reported some degree of activity limitations (70).
In SCI, some form of activity limitation typically is present from the onset of the injury. Aging may further magnify dependency issues as the individual's needs, abilities, and limitations change over time. A recent longitudinal study of individuals with long-term SCI found advancing age to be a significant predictor of functional decline. The average age when additional functional assistance was first needed was 49 years for those with tetraplegia or tetraparesis and 54 years for those with paraplegia or paraparesis (68). Functional decline or decreasing physical independence has been identified as an adverse outcome of long-term SCI. Research has shown that 22 percent of participants report a decline over a 3-year time span (71), as well as both cross-sectional and longitudinal significant increases in the need for assistance among older individuals (72).
It is encouraging that the possibilities of preserving functional ability and maintaining independence are areas amenable to intervention. These interventions include changing the mechanics which certain activities (such as transfers) are accomplished by using new equipment and devices, or modifying existing equipment. In situations where assistance from others does increase or become necessary, efforts should be made to incorporate this help into an individual's life in a way that still enables the person with SCI to maintain maximal independence, such as having the power to hire, train, and even fire helpers.
Community Integration
For various reasons, activity levels can be expected to decline with advancing age (73), and it is an all-too-common belief that disengagement from society and declining involvement in social activities is a “normal” adjustment to aging. Studies have shown variable results, with some findings indicating that decreases in community integration are not always the case, and in some cases, the extent of social participation does not decline with age (74).
The idea of community integration is a concept that goes beyond physical functioning, and includes an individual's role as an active, productive member of society who is well integrated into the family and community (75,76). Specific studies of individuals with SCI have summarized the finding that individuals with less severe neurologic injuries, of younger age, of Caucasian ethnicity, and more education will achieve greater community integration (77). Although such demographic factors (with the exception of education) cannot be changed, these variables account for less than 10 percent of the variance in social integration scores, as measured by the Craig Handicap Assessment and Reporting Technique (CHART) (78). Clearly, a variety of other factors influences successful community integration for individuals aging with SCI.
Stress, Depression, and Perceived Quality of Life
Depression and life satisfaction may be related to how well a person copes with the changes that occur as a result of aging (79). Evidence also shows that chronic stress can be detrimental to health (80), although it may not be completely accurate to assume that older people experience more stress than younger individuals (81). Findings, however, link stress and poor health with depression in older individuals (82). Because it is difficult to separate mental and physical health in older individuals, the consequences of depression in later life can be quite serious (83). In fact, studies have demonstrated that psychosocial factors such as depression are independent, etiologic and prognostic factors for coronary heart disease (84-86).
In light of the above evidence, some findings indicate that perceived quality of life is not necessarily worse for older individuals, even for those with chronic illnesses (87). Often called life satisfaction, happiness,and well-being, quality of life is a multidimensional concept, incorporating a combination of biologic, psychologic, interpersonal, social, economic, and cultural dimensions (88). As a result, aging, in and of itself, may not be specifically associated with a lower perceived quality of life.
Research regarding stress, depression, and quality of life in people aging with SCI generally supports findings in the general aging literature, although there is a tendency for baseline stress and depression to be great for people with SCI, when compared to the general population (79). A longitudinal study of aging in SCI found no significant differences in perceived stress by age, duration of injury, gender, or severity of impairment among a group of British individuals whose injuries were at least 20 years in duration (89). In fact, there was a tendency toward less stress in older individuals. In addition, results from the Baylor College of Medicine Life Status Study showed no relationship between age and stress in a sample of community-dwelling people with SCI (90).
Compared to the relatively limited information on long-term stress and depression related to aging with SCI, the study of quality of life in SCI literature has provided more insight into long-term psychosocial outcomes. Not surprisingly, it has been suggested that quality of life among people with SCI is generally lower than among those without disabilities (91,92). The research findings, however, tend to be contradictory. Whereas some studies indicate that life satisfaction for people with SCI is not necessarily negatively affected by aging (72,93,94), others find significant differences in self-perceived quality of life, with younger individuals and those injured shorter periods of time rating their quality of life better than older individuals did (28,95,96). This variation in findings may be a consequence of the difference in how older and younger individuals assess quality of life. It is clear, however, that aging is only one aspect of quality of life, and life satisfaction following SCI can also be related to overall general health, social support, community integration, and personal factors, as well as level of injury and expectations about functional abilities (94,97-101).
It becomes the responsibility of both healthcare providers and people with SCI and their families to work cooperatively in an attempt to identify the underlying factors that influence quality of life, increasing stress, or depression. This involves a careful look at the person with SCI, and his or her living situation, resources, and environment. Successful aging is the result of a well-integrated assessment of these multiple areas and making adjustments or recommendations to benefit as effectively as possible the perso0n aging with SCI.
LOOKING TO THE FUTURE
Mortality and Life Expectancy
Numerous studies attest to the finding that survival following SCI has improved dramatically, not only in the early stages but over the longer term as well (102), with life expectancies often extending into the sixth and seventh decades of life. In spite of thee improvements, however, life expectancy for the person with SCI is still much lower than that of the general population. Survival following SCI is affected not only by level and severity of injury (97,103,104), but also by age at injury (105) and decade of injury (106, 107). Although it is an encouraging finding that people with SCI are surviving longer, they consequently may be at greater risk to develop chronic health conditions typically associated with aging. In addition, many of these conditions, especially when complicated by SCI, may lead to death. Those who provide healthcare and services to this unique population will therefore encounter new challenges when attempting to facilitate the successful aging of these individuals. Working together with members of the gerontologic sciences community will help those who are providing services to people aging with SCI understand the additional complexities associated with the aging process.
The long-term management of individuals aging with SCI is not limited to clinical follow-up. Efforts should also be focused on education, both for the individuals aging with SCI and for clinicians. Through a multifaceted approach, effective strategies designed to minimize conditions and complications that occur with aging can be identified and implemented (108).
Regular physical assessments should attend not only to SCI-specific health issues, but also to those problems associated with aging in general. For example, routine mammography and Pap smears are as indicated for women with SCI as for those in the general population. In men, screening for rectal and prostate cancers should be performed routinely. Vaccinations are particularity indicated for individuals with tetraplegia and those in the older age groups. Cardiac risk assessments should be carried out every 2 to 3 years.
In addition to regular clinical monitoring of aging and SCI-specific conditions, pertinent and timely educational materials for the person aging with SCI should be made available. It should be emphasized and re-emphasized that continued rehabilitation or equipment modifications may be necessary as the years pass.
Aging need not be a topic to be avoided or one that raises concerns or fears. It is simply another facet of living with SCI. Using an integrated approach to addressing aging issues, we can gain a greater understanding of this important segment of life, develop pathways to more successful outcomes, and, ideally, help minimize the fears and stigma often associated with aging.
References