Aging with a neurological disability

Author(s): Justin Weppner, MD, Heather Asthagiri, MD, and Sara Raiser, MD

Originally published:09/20/2014

Last updated:07/05/2018

1. DISEASE/DISORDER:

Definition

The aging process causes a progressive decline in the physiological function of all organ systems and a concurrent neurological disability provides additional complexity.

The neurological conditions addressed in this review include relatively static conditions, such as spinal cord injuries (SCI) and disorders, stroke, traumatic brain injuries (TBI), non-traumatic injuries, and congenital disorders (e.g., degenerative ataxias and cerebral palsy). Progressive conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and Parkinson’s disease (PD) are also included.

Etiology

Aging is defined as the time-dependent, sequential deterioration that occurs in most living beings. Age-related loss of function includes weakness, increased susceptibility to disease and adverse environmental conditions, loss of mobility and agility, and significant physiological changes.1 Cell apoptosis, telomere shortening, medical comorbidities, degenerative conditions, and dropout of muscle and nerve fibers contribute to functional impairments.

Epidemiology including risk factors and primary prevention

Table 1. Epidemiology in the United States

Condition Annual Incidence Prevalence Life Expectancy
General population Age 65 and older: 40.3 million (13.0%)1 Age 60: 22.2 years1
Traumatic SCI 4 per 100,000 (12,000 total)
40% have concomitant TBI
259,000-1.3 million Age 20, paraplegia: 45.8 years
Age 60, ventilator dependent: 3.2 years
Stroke 795,000 (185,000 recurrent) 6.5 million Age 65: 9.5-11.5 years2
TBI 1.7 million (80% mild; 275,000 admissions)3 5.3 million require long-term assistance with activities of daily living Reduced by 7 years4
PD Ages 70-79: 93.1 per 100,0005 1% of those over 60 15 years after diagnosis5
ALS 1.5-2.7 per 100,0006 2.7-7.4 per 100,0006 2-5 years after symptom onset
MS 40-220 per 100,000 400,000 Reduced by 7-14 years7

Key epidemiological data regarding some of the major causes of neurological disabilities are summarized in Table 1. Additional details about the epidemiology of these and other neurological disorders can be found under topics related to those individual conditions.

Patho-anatomy/physiology

Consequences of the normal aging process are amplified by concomitant neurological injury.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

Care must be tailored to the individual, the neurological disease, and additional comorbidities. For instance, modifying cardiovascular risk factors after stroke can reduce future events. In addition, dementia becomes more prevalent with age, and in the general population, affects 1.5% of those aged 65-70 years and 25% of those older than 85 years. PD, ALS, and MS are all associated with cognitive impairment and dementia. Neuropsychological evaluation can identify specific deficits and determine compensatory strategies.

Specific secondary or associated conditions and complications

Secondary conditions associated with aging and neurological disability are noted in all organ systems. For example, cardiovascular disease can reduce the efficiency of mobility, visual decline can further impair balance and diabetes mellitus adversely affects many organ systems that are already compromised by the neurological disease.

2. ESSENTIALS OF ASSESSMENT

History

When collecting a history from an aging individual with a neurological disability, it is critical to capture medical details and information on premorbid function, higher level physical function (balance, coordination), psychosocial factors, support systems, spirituality, home safety, and economic stability.

Physical examination

A thorough physical exam should include cognition, strength, sensation, balance, vision, hearing, and nutritional assessment.

Functional assessment

A clinical assessment should include an evaluation of mobility and self-care ability (including activities of daily living), as well as cognition and safety (including instrumental activities of daily living).

Laboratory studies

Routine laboratory studies should be consistent with general health maintenance guidelines and relevant to the specific neurological condition. In the elderly, it is important to note that abnormalities such as electrolyte imbalance, can accentuate cognitive and functional impairment related to underlying baseline neurological disorders.

Imaging

Appropriate imaging should be performed in individuals with abnormal neurological findings or progressive neurological decline, such as recent loss of motor control or decline in cognitive function.

Environmental

With aging, balance, gait, strength, power, and endurance typically decline. A home safety evaluation can identify risk factors for injury and enhance independence in activities of daily living. Comprehensive home assessment interventions have been shown to significantly reduce the risk of falls among the elderly by 21%.11 This may include securing cords out of walkways and installing grab in the bathroom and railings next to stairs. If mobility deteriorates, assistive devices such as walkers, wheelchairs, power mobility, transfer boards, lifts, hospital beds, and bathing equipment may be considered. In addition, as visual and auditory acuity can decline with age, assistive technology such as auditory amplification devices, low vision adaptations, and augmentative communication devices can facilitate communication and safety.

Social role and social support system

An assessment of support systems for supervision and other required assistance should be completed.

Professional issues

Not all patients may be competent to make decisions about health care matters. Patients may become temporarily incompetent during acute illness or become permanently incompetent, such as in the later stages of advanced neurological diseases. Health care and other decisions must still be made, even when patients cannot make these decisions themselves. If cognition and judgment are impaired, the individual’s capacity for decision-making and the level of supervision needed should be considered. In some cases, a guardian may need to be appointed.

3. REHABILITATION MANAGEMENT AND TREATMENTS

Available or current treatment guidelines

Musculoskeletal and neurological
Musculoskeletal problems are a major cause of pain and physical disability in older adults and represent a significant contribution to the global burden of disease.12 Overuse injuries, rotator cuff pathology, compression mononeuropathies, and musculoskeletal pain are more common in aging patients with in neurological disabilities, especially in those who utilize their upper limbs for mobility. The most significant functional deficiencies contributing to impaired balance include marked loss of muscle strength, reduced range of movement of the spine and peripheral joints, and loss of joint proprioception. Physical and occupational therapists can assess joint mechanics, joint protection, mobility efficiency, and provide energy conservation techniques.

Cardiovascular
The prevalence and incidence of cardiac failure increase with age. Heart failure remains a severely debilitating condition for many older adults and can accelerate functional decline in patients with neurological disorders. Resting metabolic rate declines with increasing age and often decreases after an injury to the central nervous system. This predisposes the individual to weight gain, which can worsen functional status and lead to complications in other organ systems (musculoskeletal, skin, endocrine, etc.). If cardiovascular risk factors such as hypertension, diabetes, and hyperlipidemia are well controlled at younger ages, additional comorbidities can be minimized later in life.

Respiratory
Changes in the alveolar membrane, including loss of the alveolar–capillary interface and an increase in alveolar size due to the destruction of individual alveolar walls, are the major form of damage found in the aging lung.13 In normal aging, vital capacity (VC) declines by 40-50%. This anticipated decline can become clinically significant for individuals with neurological disorders. In SCI, individuals with higher levels of injury typically have reduced VC, though often can breathe without ventilators. However, with accompanying age-related loss of VC, a patient may require a ventilator. In ALS, the criteria for initiating non-invasive ventilation include having a VC less than half of the predicted value. Disorders such as nocturnal hypoventilation and sleep-disordered breathing are seen more often in SCI (26-65%) and stroke (40-70%), potentially resulting in daytime sleepiness, cognitive dysfunction, and medical morbidity.14,15 This should be evaluated when clinically indicated.

Gastrointestinal
Gastrointestinal motility slows with increasing age. Additionally, neurogenic bowel dysfunction with accompanying polypharmacy can increase challenges with constipation. Management often requires a scheduled and more aggressive routine. This may include adjusting diet, fluids, and medications. In the upper gastrointestinal tract, dysphagia can develop due to dental problems or progression of a neurological disease. A video fluoroscopic swallow exam or speech-language pathologist evaluation may be considered if there is concern over potential aspiration or recurrent episodes of pneumonia.

Genitourinary
Bladder incontinence among older adults is common and often treatable. Unfortunately, unwillingness to report urinary symptoms and inadequate knowledge of treatment options prevent many older adults from discussing urinary incontinence with their healthcare professionals. Nocturia occurs more commonly with increasing age and places the affected individual at a higher risk of falls while mobilizing to the bathroom. The fall risk can be reduced by: placing urinals, catheterization supplies or a commode at the bedside; transitioning to an indwelling catheter; turning lights on at night; enlisting caregiver assistance; reassessing mobility aids; securing pets; adjusting bed height; and minimizing fluids after dinner. Those with neurogenic bladder dysfunction managed with catheterization are frequently colonized with asymptomatic bacteriuria and have some degree of pyuria. This presentation is often inappropriately treated with antibiotics. Providers should be cognizant of this and treat only if there are other signs or symptoms of infection. Antibiotic overuse may lead to bacterial resistance, which could complicate antibiotic selection in the future.

Sexuality
In aging individuals, estrogen and testosterone levels decrease, and with concomitant neurological disorders, there are additional etiologies for sexual dysfunction and dissatisfaction. Treatment options include counseling, devices, and medications. In men, ejaculatory function can be altered with neurological injury. Depending on the level and completeness of the SCI, rates of intact ejaculation vary from 5-70%. After a neurological injury in women, fertility is unaffected but normal physiological changes in pregnancy may exacerbate existing conditions (skin integrity, spasticity, functional abilities, etc.). Management may include referral to fertility or high-risk obstetrics specialists, treating autonomic dysreflexia in pregnant SCI patients, renting manual or power wheelchairs during the peripartum period, and utilizing adaptive equipment for breastfeeding and childcare.

Skin
As the skin ages, many structural and functional changes naturally occur including flattening of the dermal–epidermal junction. Skin becomes more fragile with age due to reduced elasticity, blood supply, moisture content, and sensitivity. For those with neurological disabilities and impaired mobility (with or without insensate skin), it is important to closely monitor skin integrity. Although those with ALS and PD do not have significantly impaired sensation, deficits in strength, endurance, range of motion, coordination, or cognition may make it difficult to turn in bed or perform pressure relief. If moisture from urinary or fecal incontinence causes perineal skin breakdown, wound contamination, or fungal infections, alternative bladder or bowel management routines can be considered.

Endocrine
Loss of bone density is seen in normal aging, particularly in post-menopausal women. Bone loss associated with neurological disorders such as stroke and SCI is typically more severe, involves different sites, and results in more fractures. There is no consensus on the prevention or treatment of neurological osteoporosis; however vitamin D combined with calcium has been shown to reduce fall-related fractures among older individuals.16

Cognitive and psychological
Depression may occur with aging, even for individuals who were not previously affected. Rates of major depressive episodes among the neurologically impaired elderly vary from 10-40%.17 Suicide is the most serious outcome of depression, although accurate suicide rates are difficult to determine due to cultural biases and erroneous classification of particular events (such as motor vehicle accidents or drowning) as accidental deaths rather than completed suicides. The suicide rate appears to be increased in SCI, TBI, and MS.10,18,19 In the general population, the suicide rate is higher in those aged over 65 years, particularly in men older than of 75 years.19,20

Social
A neurological disability may create additional challenges in assuming family roles. Referral to appropriate interdisciplinary team members may be beneficial to address functional and psychosocial needs. Rates of employment following a neurological injury are lower compared to able-bodied individuals. Vocational rehabilitation services should be utilized to assist appropriate candidates in returning to work post-injury. For those unable to return to work, recreational therapy services can introduce meaningful leisure activities.

Preventive health
Access to preventive health and age-appropriate cancer screening becomes more challenging with mobility impairments, contractures, respiratory dysfunction, etc. Many clinics do not have accessible buildings or exam tables, mechanical lifts, rooms that can accommodate stretchers, accessible mammography machines, or staff trained to assist those with disabilities.

Polypharmacy
Several age-related factors, including decreased glomerular filtration rate and hepatic blood flow, affect the metabolism and clearance of medications. In addition, increased adipose tissue prolongs the half-life of fat-soluble medications, and a decrease in total body water raises the concentration of water-soluble drugs. Muscle atrophy is often seen in neurological conditions and can cause an artificially low serum creatinine that may lead to overestimation of the true renal function. Therefore, creatinine should be rounded up for dosing calculations to minimize supratherapeutic drug levels. In addition, age-related decline in renal function decreases clearance and increases the half-life of renally excreted drugs and metabolites. Pharmacists who have experience with these adjustments for neurological disabilities can be a valuable resource.  Several factors (multiple medications, social factors, comorbidities, functional and cognitive status, age-related physiological changes) must be considered when selecting drug therapies and dosage to maximize benefits, while minimizing adverse drug-drug or drug-disease interactions.

End of life
Regardless of age, it is important to encourage an individual to complete an advance care directive and designate a durable power of attorney for health care. These forms should be added to the medical record, reviewed periodically with the person and updated as needed. Every state has its own forms, laws and terminology. Those who travel frequently across state lines should complete forms for each state. Patients generally value discussing their advance directives with health care providers, with, only 5% of individuals reporting these discussions as too difficult.21  In addition, timely discussion regarding long-term percutaneous gastrostostomy placement and the use of ventilators should be initiated for individuals with progressive disorders.

Coordination of care

The physiatrist should coordinate with the appropriate member of the interdisciplinary team (rehabilitation nurse, physical therapist, occupational therapist, recreational therapist, social worker, psychiatrist) to offer individual resources specific to the patient’s needs. Support systems may change as patients with disabilities age, so ongoing coordination and identification of necessary resources are especially important.

Patient & family education

Discussions on aging and accompanying neurological injury should occur with the individual, family, and caregivers to ensure that information is offered and opportunity is provided for patient’s questions to be answered. Issues regarding safety, guardianship, driving abilities, etc., are important to discuss in an honest, non-judgmental, and sensitive manner.

Translation into practice: “practice pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

Distinguishing the effects of aging from those of the underlying neurological condition can be challenging but important, especially for identifying and treating potentially reversible impairments in a timely manner.

4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE

Ongoing basic science research evaluating the effect of genetic polymorphisms on the course of age-related neurological mobility impairment may be translated to clinic practice.  These genetic factors may provide risk factor stratification for those patients susceptible to a rapid mobility decline with aging.

5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE

Gaps in the evidence-based knowledge

There is a lack of evidence on the effects of aging among individuals with neurological disabilities. Given the growth of this population, there is clearly a need for further research to characterize aging-specific issues such as the topics addressed above, as well as to outline optimal management strategies. A better understanding of the effects of aging on the general population, in addition to identification of specific implications for persons with neurologic disabilities, will be crucial for treating this increasing patient population in the future.

REFERENCES

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Original Version of the Topic

Jelena Svircev, MD, Katrina Thomas, MD, Shawn Song, MD .Aging with a neurological disability. 09/20/2014.

Author Disclosure

Justin Weppner, MD
Nothing to Disclose

Heather Asthagiri, MD
Nothing to Disclose

Sara Raiser, MD
Nothing to Disclose

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