Rehabilitation is the process of assisting a person to maximize function and quality of life. Therefore, rehabilitation matters to people with neuromuscular diseases because it enables them to reach their fullest potential despite the presence of a disability. Too often, patients are told “there is nothing we can do” for their neuromuscular conditions. At times this judgment is not expressed explicitly, but transpires from nonverbal cues during patient encounters. Such attitudes cast a dark shadow on the therapeutic alliance between the physician and the patient and lead to disengagement and lower quality of care. On the contrary, here we will argue that “there is always something we can do” for our patients. While there are no life-prolonging treatments for many neuromuscular disorders, interventions are often available that can assist people in continuing to function independently and safely, both in their vocational and personal lives, manage their symptoms, and live fulfilling lives in spite of the presence of a physical impairment. In this chapter, we will look at neuromuscular diseases from a rehabilitation perspective. We will first review the role of exercise, orthoses, mobility aids, adaptive equipment, and environmental modifications with respect to their impact on function and quality of life. We will then develop a rehabilitation framework to address common neuromuscular problems such as axial weakness, spinal deformities, proximal upper and lower limb weakness, hand weakness, foot drop, falls, foot abnormalities, joint contractures, spasticity, pain, ptosis, dysphagia, and dysarthria.
Rehabilitation is sometimes overlooked because it is not clear who is in charge of it and when it should begin. It is commonly accepted that the multifaceted rehabilitation needs of neuromuscular patients are best served by a multidisciplinary team that may include neurologists, physiatrists, nurses, physical therapists (PTs), orthotists, occupational therapists (OTs), speech and language pathologists (SLPs), nutritionists, respiratory therapists, psychologists, palliative care experts, pain medicine specialists, vocational consultants, recreational therapists, and social workers. Receiving care in a multidisciplinary clinic has been suggested to benefit people with certain neuromuscular diseases [i.e., amyotrophic lateral sclerosis (ALS)] by optimizing health care delivery and, possibly, prolonging survival and enhancing quality of life.1 But what is the role of each member of the multidisciplinary team and who is responsible for advocating for the patient and for coordinating care among the different rehabilitation professionals? Neuromuscular specialists periodically assess the patients’ functional status in a neuromuscular clinic. We therefore argue that the neuromuscular specialist, most often a neurologist or a physiatrist, is ideally positioned to lead the rehabilitation efforts while leveraging the expertise of the different team members. This may seem like a daunting and time-consuming task. However, most of what is required is simply adequate knowledge of the available tools and effective communication. A clear understanding of the role and capabilities of each team member is essential for proper referrals and results in higher quality of care and a time-efficient practice.
Neuromuscular specialists most commonly refer patients to PTs, OTs, and SLPs. While there is some overlap between the skill sets of PTs and OTs, PTs specialize in gait assessment and training, biomechanics, core stability, balance, and functional mobility such as transfers.2 PTs also specialize in teaching stretching techniques and developing aerobic conditioning and strengthening exercise programs. OTs assist people to participate in the everyday activities (occupations) they need and want to do. They focus on proper posture and ergonomics related to upper limb functional activities such as feeding, grooming, dressing, and using a telephone or a computer. Both types of therapists utilize active and passive therapeutic exercises, physical modalities (such as heat, cold, and electrical stimulation), and manual techniques (such as massage, joint mobilization, and myofascial release techniques) to address pain and impairments in strength, flexibility, balance, posture, and endurance. They may work in close contact with orthotists if orthoses (i.e., braces) are indicated and they may recommend splints, assistive devices, adaptive equipment, and/or home modifications. Some PTs and OTs specialize in assistive technology, such as systems to allow access to computers and environmental controls (e.g., lights, television, etc.) for people with motor impairment.
SLPs manage disorders of speech, language, cognition, communication, and swallowing. Some SLPs specialize in augmentative and alternative communication (AAC) technology to provide systems to supplement or replace natural speech. As an example, people with ALS may utilize voice banking to digitally record words and phrases while still able to do so, for later inclusion in a communication device. Some AAC systems incorporate computer access capabilities and options for environmental controls, both of which can generally be mounted on a wheelchair. When dysphagia is suspected, SLPs utilize clinical oral motor assessments as well as instrumental measures [i.e., fiberoptic endoscopic evaluation of swallowing (FEES) and modified barium swallow (MBS) study] for proper assessment of the swallowing impairment and to recommend diet modifications and compensatory strategies. They may also work with dieticians to optimize meal planning. Depending on the individual patient’s needs, additional healthcare professionals such as respiratory therapists, psychologists, palliative care experts, pain medicine specialists, vocational consultants, recreational therapists, and social workers might provide additional expertise to address specific rehabilitation needs.
While diagnostic procedures are often complex and energy consuming in neuromuscular medicine, it is best to start thinking “functionally” early on. The International Classification of Functioning, Disability and Health (ICF) model defines impairments as deficits within the performance of an organ or body system. For example, foot drop is an impairment caused by the weakness of a group of muscles that can result from neurogenic causes or, less frequently, other neuromuscular disorders, such as myopathy or disorders of neuromuscular transmission. Activity limitation in the ICF model refers to deficient performance of basic functional tasks, such as slowed walking speed, whereas participation restriction refers to the consequent inability to fulfill a role within the home or community environment, such as self-care activities and shopping.3 Rehabilitative interventions might target impairments, activity limitations, and/or participation restrictions.4 Different strategies (and different outcome measures) need to be considered depending on the goal of therapy. As an example, the therapy directed toward an impairment, such as exercise and bracing to target impaired range of motion (ROM) in a weak hand, might have great functional impact even if the actual degree of improvement in ROM is small. In this example, after intervention, the person might be able to perform a previously limited activity, such as typing on a computer, and as a result be able to participate in social activities which were previously restricted. Of note, similar rehabilitation strategies can often be utilized regardless of the exact etiology.
Rehabilitation should ideally start at the first patient encounter. Certainly, rehabilitation should begin before maladaptive patterns develop. As an example, it is common experience that it is much easier to prevent, rather than treat, contractures. This notion becomes especially important in rapidly progressive diseases such as ALS and requires forward thinking on the part of the rehabilitation team. We cannot emphasize enough how crucial early intervention is for people with progressive neuromuscular weakness. For instance, even in the early stages of the disease, before the onset of severe weakness, therapists can educate patients on energy conservation techniques such as pacing, taking rest breaks, and using bracing and adaptive equipment when performing demanding activities, perhaps on an intermittent basis. Such interventions might help reduce fatigue, a highly prevalent symptom in many neuromuscular diseases.5–7 Further, early focus on biomechanics, ergonomics, stretching, and bracing helps people to remain as functional as possible and can help to delay or even prevent many of the negative sequelae of impaired strength.
Rehabilitation should be approached in a problem-oriented fashion, focusing on what the person needs most at any particular time in the course of his/her disease in order to maintain maximal function and quality of life. Thus rehabilitation may include management of one or more impairments (e.g., impairment in strength, ROM, and tone), activity limitations (limitations with walking, standing, transferring, self-feeding, toileting, dressing, grooming, and bathing), and participation restrictions (such as participation in sports and leisure activities). Importantly, rehabilitation needs may change over time. Clinicians need to be aware of the disease’s natural history and resource availability in order to anticipate needs and recommend interventions at appropriate times. In addition, rehabilitation strategies should be attentive to the person’s environment and his or her family and support systems. Environmental modifications and family training are therefore integral to the rehabilitation process.
Given the multitude of functional challenges that many people with neuromuscular diseases may experience, it is best to approach them systematically by making a list of issues or a “rehabilitation assessment and plan” (rehabilitation A&P) that should be included in clinic notes alongside the medical A&P and reviewed at every follow-up visit. Developing a rehabilitation A&P requires consideration of the person’s disease in relation to the changes in functional status that it creates. An individual with a generalized neuromuscular condition such as ALS or muscular dystrophy may present with weakness in multiple muscle groups which the clinician carefully records with periodic manual muscle testing performed at every follow-up visit. But what is the resulting activity limitation, and what can we do about it? If a person with ALS develops hand weakness, how does this impact his or her ability to carry out desired activities of daily living (ADLs), such as dressing and grooming, or instrumental ADLs (more complex tasks such as care of children or use of telephones and other communication devices)? Can we suggest any strategies to compensate for or adapt to the hand weakness? Is abnormal muscle tone a limitation at this time? Is the patient at risk of developing finger contractures? Can the work environment be modified to allow him or her to continue to work despite the hand weakness? Can the caregivers be trained to help with ROM exercises? Which healthcare professionals might provide optimal expertise to address this problem at this time (OTs, vocational consultants, and so on)? Can the person benefit from assistive devices to maintain independence with feeding, dressing and toileting? If the hand weakness prevents him or her from comfortably using telephones and computers, which assistive technology system can we recommend? Clearly, the extent and treatment goals of the rehabilitation A&P may differ substantially depending on the underlying pathologic process. Impairments may be limited to one domain or involve multiple systems, may be static or progressive, and may be impacted by comorbidities, such as pre-existing musculoskeletal abnormalities, and environmental limitations. Rehabilitation goals may include restoration of function for some patients. When restoration of neurologic function is not achievable, teaching adaptive or compensatory techniques may allow the person to maintain independence and prevent negative sequelae of muscle weakness such as contractures and pain. Palliative care might be needed in some neuromuscular diseases and might be viewed as the end of the rehabilitation spectrum.
In people with progressive disorders such as ALS, hereditary neuropathies, and muscular dystrophies, it is crucial to frequently reassess rehabilitation strategies and modify them with changes in disease status. As an example, if a person with ALS, Charcot-Marie-Tooth (CMT), or a distal myopathy develops ankle dorsiflexion weakness, an ankle-foot orthosis (AFO) may be prescribed to improve gait efficiency, conserve energy, and reduce fall risk. A few gait training sessions with a PT are important to successfully learn to ambulate with a brace. Later in the course of the disease, when the individual loses the ability to ambulate, a PT should provide recommendations for a customized wheelchair. A few therapy sessions might also be indicated for the patient and his or her caregiver to provide training on stretching and ROM exercises to prevent contracture formation. If the person then develops pain or is uncomfortable when sitting in the wheelchair, wheelchair evaluation should be performed and adjustments made accordingly.
Rather than writing generic therapy prescriptions, it is best to address specific problems (e.g., gait training, transfer training, wheelchair evaluation, etc.) and periodically reassess needs. Working in close contact with therapists who are familiar with neuromuscular diseases will help ensure that therapy sessions are focused on what the individual really needs at that specific time. Of note, insurance carriers limit the number of therapy sessions for which people are eligible in a given period of time. Continued skilled therapy services (i.e., performed by a skilled health care professional such as a PT) to maintain current functional status have traditionally been denied in chronic conditions because there was no expectation for the person to “improve” (a concept known as “improvement standard”). A recent settlement in the class action “Improvement Standard” lawsuit (Jimmo vs. Kathleen Sebelius) upheld the right of patients to continue to receive reasonable and necessary care to maintain their condition and prevent or slow decline. The type of care covered under this settlement, however, refers only to skilled care and not to maintenance programs that can be performed by the patient or with the assistance of nontherapists, including unskilled caregivers. At this time of significant changes in the American health care system, the practical impact of this settlement on the rehabilitation of people with progressive neuromuscular diseases remains to be determined. Coverage for durable medical equipment (DME) might also be limited. Loaner programs and support from patient advocacy organizations might help ease the financial burden and allow people to try different models of the same type of device before buying expensive material that they might not want or be able to use effectively. Of note, once patients are enrolled in hospice, most, if not all DME, must be paid out of pocket. Therefore, it is important to know the natural history of the disease and purchase equipment accordingly.
We will now review the tools that the rehabilitation team can use to assist people to maximize function and quality of life. We will then suggest a practical approach to address the rehabilitation problems that are most frequently encountered in neuromuscular medicine. However, one should keep in mind that rehabilitation science is in constant development and the clinical problems posed by particular patients might be unique and require creative thinking on the therapists’ part. Therefore, the approach suggested here should not be viewed as a “fix-all recipe” but rather as a platform for discussion. Most importantly, with this chapter, we want to draw attention on the importance of periodic functional assessments and the need to think of rehabilitation as a fundamental part of neuromuscular medicine practice.
REHABILITATION TOOLS AND STRATEGIES FOR THEIR USE
It is not infrequent for people with neuromuscular diseases to inquire about exercise. Physical activity and exercise are an integral part of the premorbid lifestyle for many neuromuscular patients. Therefore, patients often ask whether exercise is safe, whether it can help slow down their disease, and what type of exercise is recommended for their particular condition. It is not easy to answer these questions. Strictly speaking, these are questions that cannot be answered based on the currently available evidence. Unfortunately, there is a paucity of literature on the topic of exercise in neuromuscular disorders.8
Exercise studies in neuromuscular medicine are limited in both quantity and quality. Limitations in the available studies include small sample size, heterogeneous patient population, uncontrolled and nonrandomized design, short-term training, variable exercise protocols, and outcome measures. Some investigators have attempted to circumvent difficulties in recruiting a nonexercising control group with similar disease characteristics by asking the subjects to exercise only one side of the body, with the contralateral side serving as control. A nonexercised limb, however, is not an appropriate control due to the phenomenon of cross-education. Unilateral training induces strength gains not only in the trained limb, but also in the homologous muscles of the contralateral limb.9 Therefore, comparisons should be made between training and nontraining patients. A recent Cochrane review on exercise training for myopathies identified only three high-quality randomized clinical trials.8 Additional evidence mostly comes from observational or uncontrolled trials and recommendations have been primarily based on the consensus of the expert review panel.10 The types of exercise that are relevant to people with neuromuscular disorders are flexibility, resistance, aerobic, and balance exercises (Table 5-1).
|Type of Exercise||Description||Benefits|
Part of the standard of care for the prevention and management of contractures
Might help to manage pain and spasticity
|Resistance/strengthening||Repeated muscle actions against resistance:||Potential role in:|
|Aerobic||Dynamic activity using large muscle groups||Potential role in:|
|Balance||Balance training using different modalities|
Potential role in:
More disease-specific research needed
Flexibility training involves stretching and ROM exercises. The potential benefits of this type of exercise include prevention and treatment of spasticity and contractures, as well as the pain that often accompanies them. Because many people with neuromuscular diseases are at risk for the development of these complications, flexibility training is often incorporated into the standard of care.11
Neuromuscular specialists are ideally positioned to advocate the early initiation of flexibility training. Supervision from a PT is often needed to initiate a correct stretching program. PTs may then periodically reassess progress, guide program modifications, or suggest further treatment modalities such as positioning, splinting, bracing, orthoses, and standing devices. Stretching, however, should not be limited to therapy sessions and should be done daily for any specific joint or muscle group that is at risk for contracture development. Stretching can be done at home, school, or work, as well as in the clinic.11 It is important for people to understand that stretching can be safely performed outside of the clinic environment either independently or with caregiver assistance, and that consistency produces the best results. In this respect, caregiver involvement is essential. When individuals cannot perform active stretching due to significant weakness, active-assisted and/or passive techniques may be implemented with caregiver’s help.
In comparison with data from people with neuromuscular diseases, the quality of the evidence on the beneficial effects of aerobic and strengthening exercise in the able-bodied population is excellent. In healthy individuals, moderate-intensity physical activity significantly improves overall health. In addition, it is related to improving the outcomes of several chronic diseases, such as heart disease, stroke, and type 2 diabetes. Based on this evidence, the American College of Sports Medicine (ACSM) declared that “Exercise is medicine“” inviting physicians to write exercise prescriptions to promote physical activity and exercise as standard parts of disease prevention and medical treatment.12
Here we define aerobic exercise training, or cardiorespiratory fitness training, as an activity that uses large muscle groups, that can be maintained continuously, and that is rhythmical and aerobic in nature such as walking, hiking, running, cycling, and swimming. Guidelines for aerobic training for the general population were published in 2008 by the US Department of Health and Human Services. The Physical Activity Guidelines for Americans state that adults aged 18 to 64 should do 150 minutes a week of moderate-intensity or 75 minutes a week of vigorous-intensity aerobic physical activity, in bouts of at least 10 minutes and preferably spread throughout the week. The same guidelines state that older adults (aged 65 and older) and individuals with disabilities should follow the same guidelines, but, if this is not possible due to limiting health conditions, they should be as physically active as their abilities allow and avoid inactivity.
The same guidelines also recommend performing muscle-strengthening activities that involve all major muscle groups 2 or more days per week. Strength training is defined as an activity performed to improve muscle strength and endurance and is typically carried out by making repeated muscle actions against resistance.13 Strength training includes different types of muscle actions: isometric (i.e., performed at a constant muscle length with no joint movement, as in wall squat hold and plank exercises), concentric (i.e., the muscle generates force while shortening, as when lifting a dumbbell towards the body), and eccentric (i.e., the muscle generates force while lengthening, as when lowering a weight away from the body or landing back on the ground after jumping). For healthy adults, the ACSM recommends one set of about 10 exercises to condition all major muscle groups, 2 to 3 days per week. Healthy adults should complete at least one set of 8 to 12 repetitions per exercise at loads of at least 45% to 50% of the one-repetition maximum (1RM) (which is the maximal load that can be lifted throughout the full ROM once).13,14
But how can we translate these general guidelines into exercise recommendations for people with neuromuscular diseases? We will first review the available studies and then draw offer some general recommendations, at all times being mindful of the overarching principle of primum non nocere. When evaluating studies of the outcome of exercise in different patient populations, one should keep in mind that slowing the rate of functional impairment is a positive result in progressive neuromuscular diseases, while actual gain of strength or aerobic capacity might be a goal only in selected conditions. Additional factors that need to be considered are the presence of comorbidities (such as heart and restrictive lung disease in certain neuromuscular conditions), the specific disorder, rate of progression, and expected natural history.
In the available studies, primary outcome measures have mostly been limited to effects at the impairment level: aerobic capacity and measures of muscle strength. Ideally, the primary outcomes of exercise studies should also include measures of function such as improvement in the ability to walk, perform ADLs, and participate in work, sports, and recreational activities, as these are the outcomes that really matter to patients. Secondary outcomes for exercise training have included measured of pain or fatigue, quality of life, and mood. These secondary outcome measures are very important to consider as well, given the high prevalence of these problems in many neuromuscular diseases.5–7,15,16
Preclinical evidence gathered in the transgenic mutant SOD1 mouse model of ALS has suggested a potential benefit from moderate endurance exercise with delay in disease onset and survival.17–19 In these mice, however, high-intensity endurance training was shown to hasten the decrease in motor performance and death.19,20 In humans, a study by Drory et al. suggested that a regular moderate exercise program (30 minutes or less daily) might have a positive effect on disability in people with ALS.21 The study included 25 ALS subjects who were randomized to perform a moderate daily program of activities as opposed to avoiding any physical activity beyond their usual daily requirements. At 3 months from the initiation of the study, subjects who performed regular exercise showed less deterioration on the ALS Functional Rating Scale (ALS-FRS) and the Ashworth spasticity scale.21 At 6 months, there was no significant difference between the groups, although a trend towards less deterioration was observed in the treated group.21 Bello-Haas et al. have recently analyzed strength training in a randomized trial which included 27 ALS subjects.22 The study involved 6 months of training, three times a week, following an individualized program. The resistance exercise group had significantly better function, as measured by total ALS-FRS scores, and quality of life, without adverse effects as compared with subjects receiving usual care.22 These studies suggest that moderate exercise might be safe for people with ALS, but are too small to draw definitive conclusions. Additional research is ongoing to confirm these findings and determine whether exercise might actually improve function in this population.
There is only one randomized clinical trial on the effect of strength training in CMT disease. In this study, 29 CMT subjects were randomized to 24 weeks of progressive resistance exercise of their lower limbs which was performed three times a week.23 Subjects in the training arm reported a moderate increase in knee torque without adverse effects.23 Other small studies reported moderate strength gains in CMT patients compared to their baseline values.24,25 Positive effects of aerobic exercise on fatigue have also been reported in this patient population.24
Preclinical studies in the mdx mouse model of Duchenne muscular dystrophy have led clinicians to advise against exercise in the dystrophinopathies. Dystrophin is an important structural protein and animal studies have demonstrated contraction-induced muscle injury in dystrophinopathy, especially after eccentric exercise.26–29 In humans, the few available studies have been small and have provided conflicting results precluding any definitive conclusions.28,30 High-resistance strength training and eccentric exercise are universally considered inappropriate across the lifespan owing to concerns about contraction-induced muscle-fiber injury.11 However, sub-maximum aerobic exercise is recommended by some clinicians, especially early in the course of the disease, in order to avoid disuse atrophy and other secondary complications of inactivity.11 Most clinicians advise boys with dystrophinopathy who are ambulatory or in the early nonambulatory stage to participate in regular gentle functional strengthening and recreation-based activities in the community. In this respect, low-impact activities such as swimming appear most beneficial.11 The optimal level of exercise for people with dystrophinopathy is the subject of current research protocols.31–33
There is only one randomized clinical trial of strength training versus no training in adults with facioscapulohumeral muscular dystrophy (FSHD). The trial involved 65 participants and lasted 52 weeks.34,35 The strength program in this study appeared to be safe, with only limited positive effects on muscle strength and volume. A study of 12 weeks of aerobic cycling showed a significant increase in aerobic capacity compared to baseline in eight subjects with FSHD with no signs of muscle damage.36 Altogether, these studies suggest that “normal” participation in sports and work appears not to be harmful.8 On the other hand, there is insufficient ground for general prescription of exercise programs in FSHD.8,37
One randomized clinical trial compared the effect of 24 weeks of strength training versus no training in adults with myotonic dystrophy.23 Neither strength gains nor muscle damage was demonstrated in the exercise group compared to controls. A study of 12 weeks of aerobic training showed that participants with myotonic dystrophy type I improved their aerobic capacity compared to their baseline without any adverse effects.38 Based on the available evidence, it may be inferred that moderate resistance and endurance exercise is probably safe in individuals with myotonic dystrophy, but there is still insufficient evidence of benefit.8
Until the early 1990s, patients with polymyositis (PM) and dermatomyositis (DM) were discouraged from exercising out of concern that it might exacerbate muscle inflammation. More recent work, however, suggests that moderate-intensity aerobic exercise does not result in worsening muscle damage, at least as assessed by creatine kinase (CK) levels, and might in fact improve aerobic capacity.39–42 The first randomized controlled study of aerobic exercise in adult PM/DM included 14 patients with chronic disease, defined as subjects with proximal muscle weakness due to PM/DM for at least 6 months and stable drug therapy over the 3 months prior to initiation of the program. After 6 weeks of training (bicycle exercise and step aerobics) there was an increase in oxygen uptake in the exercise group compared with the sedentary controls.39 The same training paradigm was later reported to be safe and to result in improved aerobic capacity in a longer prospective nonrandomized study of 6 months of exercise.43 A few open-label studies also supported the safety of resistance training in recent-onset disease, reporting unchanged CK levels after short-term exercise periods.44,45 Analysis of CK levels is the most commonly used marker for muscle inflammation in exercise studies in myositis patients. However, CK levels do not always correspond to muscle function or disease activity. Alexanderson et al. investigated MRI scans of the thighs in 7 out of 11 patients with recent-onset myositis participating in a 12-week resistance exercise program.44 In the follow-up MRI scans, after 12 weeks of exercise, none of the cases had additional areas of increased signal as compared to the first scan, supporting the safety of the exercise protocol.44
Little is known about the role of exercise in inclusion body myositis (IBM). A home exercise program consisting of 15 minutes of progressive strength training and a 15-minute walk performed 5 days a week for 12 weeks did not result in adverse effects on histopathology or significant change in serum CK level, but did not improve muscle strength.46 More recent work by Johnson et al. showed that a combined 12-week resistance and aerobic exercise program resulted in improved aerobic capacity in seven IBM patients compared to their baseline.47
People with mitochondrial myopathies suffer from exercise intolerance due to their impaired oxidative capacity and physical deconditioning. Cejudo et al. recently reported a randomized clinical trial of combined aerobic and resistance exercise analyzing the effects of 12 weeks of training in 20 people with mitochondrial myopathy (cycle exercise and upper-body weight lifting performed 3 days a week).48 Training increased aerobic capacity and resulted in improved muscle strength.48 These results are in agreement with numerous other studies supporting the notion that moderate endurance exercise increases aerobic capacity in patients with mitochondrial myopathies.49–52 A recent study of 12 weeks of resistance exercise strength training in a group of mitochondrial myopathy patients carrying a single, large-scale deletion of mtDNA resulted in strength gains.53 Whether or not these results are applicable to other types of mitochondrial myopathy remains to be determined.
Patients with McArdle disease are susceptible to exertional cramps and rhabdomyolysis. In the past, because of the risk of rhabdomyolysis, many people with McArdle disease have been advised to avoid exercise. However, physical inactivity may worsen exercise intolerance by further reducing the limited oxidative capacity caused by blocked glycogenolysis.54 Haller et al. examined the effect of a 14-week regimen of aerobic training on a cycle ergometer (30 to 40 minutes a day, 4 days a week) in eight subjects with McArdle disease.54 They reported significant increases in exercise capacity with no adverse effects, in agreement with other small, nonrandomized studies supporting the use of moderate-intensity aerobic exercise for these patients.55,56 The consensus is to advise individuals with McArdle disease to engage in regular, moderate aerobic activities to prevent deconditioning.57 On the other hand, intense aerobic or strengthening exercises are contraindicated. Furthermore, any bout of moderate exercise should be preceded by 5 to 15 minutes of low-level “warm up” exercise. This promotes the transition to a “second wind” in which exercise capacity is increased because of increased mobilization and delivery of extramuscular fuels.58
Many patients with neuromuscular diseases exhibit impaired balance due to a combination of sensory neuropathy, muscle weakness, and/or spasticity and are therefore at risk for falls. Whether balance training reduces this risk has not been well studied. A few small recent studies performed in patients with diabetic neuropathy suggest that balance training might result in improved balance and trunk proprioception.59–64 Further research is needed to determine whether these early promising results are applicable to other patient populations and whether training might result in increased independence and lower risk of falls.
Physical activity should be viewed as a way of improving quality of life and not just a tedious set of exercises. Many people enjoy participation in sports and other recreational activities more than individual training. Previously, it had been thought that having a disability would preclude people from sports participation. Fortunately, over the last several decades, many different groups and organizations have developed adaptive sports for a variety of patient populations. Virtually any sport can be adapted to different levels of disability (Fig. 5-1). It is important to work with organizations and therapists that have extensive experience in adaptive sports to ensure that the level of modification is safe and appropriate for the individual patient’s diagnosis and clinical status. The benefits of participation in adaptive sports include engagement with peers, accomplishment of goals that were thought to be out of reach, and improved mood, confidence, and self-esteem. In addition, sports can offer opportunities for people to maintain mobility in an integrated environment. Participation in adaptive sports may be especially important in the pediatric population, as kids enjoy learning through play and recreation.
Adaptive sports. (A) Windsurfing can be adapted to athletes with different disabilities, including wheelchair users. The athlete sits in a high back chair and controls the back sail on a tandem board that can plane at speeds over 32.19 km/h (20 mph). Athletic trainers control the front sail and help keep the board balanced. (Used with permission of Ross Lilley, AccesSportAmerica.) (B) Power soccer: athletes who use power wheelchairs for mobility can participate in power soccer. A footguard is attached to the front of their power chair. This guard is for protection and is also used by the athletes to kick, dribble, and block the ball. In competition, chairs are restricted to a top speed of 10 km/h (6.2 mph). (Used with permission of Scot Goodman, Scot Goodman Photography.) (C) Adaptive skiing: skiing can be performed with a variety of adaptive equipment to be suitable for athletes with different disabilities. In this photo, a power wheelchair user sits in a chair on a bi-ski and is guided down the slope by a trainer. (Used with permission of Paul Martino, Adaptive Ski Program, New Mexico.) (D) Paddling: this set-up enables athletes to stand up or sit down paddle with the direction and support of a trainer next to them. (Used with permission of Ross Lilley, AccesSportAmerica.)
While research is limited as reviewed above, recommendations for general exercise programs for people with neuromuscular diseases have been developed by several consensus panels and are summarized in Table 5-2.10,11,65,66 Obviously, the level of training and expected outcomes depend on the diagnosis, disease severity, and rate of progression. As an example, people who are recovering from a single episode of neuralgic amyotrophy or Guillain–Barré syndrome are expected to improve their strength over time and exercise can potentially help their recovery, although this assumption is based solely on the known benefits of exercise in the healthy population rather than patients with disease. For patients with slowly progressive disease, exercise might help avoid secondary disuse or deconditioning weakness. On the other hand, some patients with rapidly progressive neuromuscular diseases might already be using their muscles at a maximal level while performing their daily activities. One should keep in mind that there is great variability in muscle strength among different muscle groups in individuals with different types and stages of neuromuscular disorders. Depending on the degree of weakness, some muscles may already be overworked. These specific muscles may need to rest and not perform additional resistance exercises. It should be noted, however, that additional research is needed before clearly defined exercise protocols can be prescribed in any specific disease population. Until then, one can be guided by the important principle of safety while drawing from the currently available studies. With regards to safety, the consensus is to allow sub-maximum aerobic training (either structured exercise or as part of recreational activities) for most patients in order to avoid deconditioning which would compound the existing weakness. In addition, when leg weakness is present, it is important to choose a mode of exercise with minimal risk of injury from falling such as recumbent stationary bike as opposed to treadmill.
|Type of Exercise and Potential Benefits||Practical Considerations|
|Flexibility training is safe and helps prevent contracture formation; it might help with pain and spasticity management|
|Moderate, sub-maximum aerobic exercise is probably safe for most patients, and might help prevent deconditioning and loss of cardiopulmonary fitness|
|Moderate resistance exercise may help maintain or improve strength in muscles with an initial Medical Research Council (MRC) grade 3/5 or better|
|For all types of exercise, the level of training depends on the diagnosis, stage, and severity of disease|
Resistance exercise programs might be added as long as one is careful to avoid overwork weakness. Muscles that do not have antigravity strength should not be exercised. Repeated eccentric muscle actions should be avoided. Eccentric muscle actions result in high force production. In healthy adults, they provide an important training stimulus leading to muscle hypertrophy.13,67 However, eccentric muscle activities are more likely to result in microdamage at the muscle level. The concern is that, in individuals with underlying muscle disease, this may result in long-lasting or irreversible muscle damage, as suggested by some preclinical studies in the mouse model of Duchenne muscular dystrophy.29
With any type of exercise program, it is important to pay attention to clinical signs of overwork such as excessive postexercise fatigue, pain, weakness, and delayed-onset muscle soreness, and modify physical activity accordingly.
Orthoses (braces) are devices worn on a person’s body to improve function, provide comfort, conserve energy, and prevent deformity. Orthoses can be prefabricated or custom made. Therapists and orthotists with experience with neuromuscular diseases can provide invaluable input as to the best orthosis to suit the individual patient’s needs. Importantly, they can help adjust the orthosis as the status of a patient’s functional needs change with time. Patient tolerability varies greatly; therefore, patient feedback on the comfort and fit of the device is paramount.
Several types of cervical orthoses, or collars, are available to support the neck. For mild weakness, a soft foam collar may be tried first as it is comfortable to wear and well tolerated. Some people with head drop use a baseball cap attached to straps around the trunk (or “baseball-cap orthosis”68). For moderate to severe weakness, collars with an open air design such as the Headmaster“ or similar models are generally well accepted and provide more support than soft collars. Other types of collar, such as the traditional Philadelphia, Aspen, or Miami-J collars provide more stability. However, these collars are often poorly tolerated due to discomfort at points of contact and a sense of warmth and confinement.
The primary goal of thoracolumbosacral orthoses (TLSOs) or lumbosacral orthoses (LSOs) in patients with neuromuscular diseases is comfort. In prepubertal children at risk for neuromuscular scoliosis, TLSOs may be utilized to provide support to the spinal column during growth, although the brace cannot prevent curve progression. Molded seating supports can also be used to provide additional comfort and stability when seating. TLSO/LSOs might be helpful in adult patients as well to provide proprioceptive input, improve alignment, and ease back pain.
Many different upper limb orthoses exist. Some orthoses are used to compensate for weakness and improve function, whereas others are prescribed to allow for proper positioning, provide comfort, and prevent or treat joint contractures.
Shoulder support systems are used in neuromuscular patients with proximal weakness who experience shoulder subluxation and/or pain, as can be seen in some muscular dystrophies and motor neuron disorders. Support systems are used to approximate the head of the humerus in the glenoid fossa, with the goal of providing comfort and pain relief. It is important, however, to choose an appropriate orthosis. Single-strap hemislings position the arm close to the body in adduction, internal rotation, and elbow flexion and, with prolonged use, might promote contracture development. On the other hand, axilla roll slings (“Bobath” slings) and humeral cuff slings help to reduce shoulder subluxation without immobilizing the arm in flexion.69 Therapists can also recommend adjustments to seating systems and arm rests for individuals who use wheelchairs for further arm support.
The balanced forearm orthosis is a functional orthosis for people with shoulder abduction weakness designed to increase independence in performing daily activities. The orthosis supports the weight of the arm against gravity while allowing for independent horizontal movement. It can be placed on a desk or mounted on a wheelchair and is used for tasks such as self-feeding and grooming.
Splints are hand orthoses for people with intrinsic hand muscle weakness (Fig. 5-2). They can be purchased off the shelf or can be custom made by orthotists and OTs. Resting hand splints are used during the day or at night to maintain muscle length in patients at risk of finger flexion contractures (Fig. 5-2A). Anticlaw splints can reduce claw hand deformity and improve grasp by limiting metacarpophalangeal (MCP) extension. Dynamic finger extension splints are used in individuals with finger extension weakness who still have adequate finger flexor strength. This splint extends the MCP joints so that extended fingers can flex and grasp objects. The opponens splint helps patients with prehension difficulties due to thumb weakness by keeping the thumb in an abducted and opposed position (Fig. 5-2B). The volar cock-up splint supports the wrist in 20 to 30 degrees of extension and is used in people whose wrist extension weakness prevents them from grasping (Fig. 5-2C). The tenodesis orthosis (wrist-driven prehension orthosis) allows an individual with finger flexor weakness to create a three-jaw chuck pinch using wrist extension. Splints to correct single digit deformities are also available.
The most common type of orthotic device prescribed by neuromuscular specialists is the AFO (Fig. 5-3). AFOs are used by patients with ankle dorsiflexion weakness to promote clearing of the toes and foot during the swing phase of gait, thus leading to a safer and more efficient ambulation. They are also used to prevent the development of ankle plantar flexion contractures. It is important, however, to carefully select candidates for bracing as an inappropriate brace might actually impair function. When patients need AFOs, it is best for them to be evaluated in brace clinics where PTs and orthotists work in close contact to provide customized AFOs and modify them as needed. Brace customization and modification is essential to ensure the best possible fit, patient comfort and compliance, as well as maximize functional outcomes. A few sessions of gait training with a skilled therapist are also needed to optimize braced gait. Last but not the least, patients should be instructed to perform skin checks on a regular basis and skin evaluation should be part of routine follow-up care. If skin redness, pain, or callouses develop, the brace should be promptly examined and adjusted by the orthotist. AFOs must be used with shoes which are deep and wide enough to accommodate them. They fit quite well in sneakers although they might be used with other types of shoes as well. It is best to always use shoes with the same heel height in order not to alter gait biomechanics while wearing a brace. Shoes should be in good condition as worn out shoes may affect the gait pattern and lead to reduced brace effectiveness. Some people do not want to wear ankle braces despite medical recommendation. In these circumstances, the use of footwear that crosses the ankle and is snug, such as lace-up boots, high-top sneakers, or even cowboy boots, can help provide at least some support to the ankle.
Ankle-foot-orthoses (AFOs). (A) Carbon fiber dorsiflexion assist orthosis. (B) Plastic posterior leaf spring (PLS) AFO. (C) Carbon fiber PLS AFO. (D) Plastic hinged AFO (pediatric). (E) Plastic solid AFO. (F and G) Two different models of floor reaction orthoses (FROs). (Used with permission of Aaron Norell, Orthotist and Prosthetist, Spaulding Rehabilitation Hospital, Boston, MA.)
AFOs come in many different models and can be modified to suit different clinical needs (Fig. 5-3). They are generally made of either plastic or carbon fiber, with the latter being a lighter-weight option. For people with mild foot drop, dorsiflexion assist orthoses may suffice (Fig. 5-3A). These braces are lightweight and incorporate a spring that generates a dorsiflexion assist moment. Another option for mild foot drop is the posterior leaf spring (PLS) AFO (Fig. 5-3B and C). This is an orthosis with medial and lateral trim lines placed posterior to the malleoli. These braces are somewhat flexible and allow some plantar flexion to occur during heel strike. Because of their flexibility, they might not be the best choice for patients with increased tone. Hinged (articulated) AFOs include an ankle joint and are appropriate for patients with moderate weakness of ankle dorsiflexion (Fig. 5-3D). Transferring from sit to stand and negotiating stairs is easier with a hinged AFO than with a solid model, but good quadriceps strength is needed to use them. A plantar flexion stop can be incorporated into the design of a hinged AFO to prevent plantar flexion beyond a certain angle, which might be useful when spasticity is a problem. Solid AFOs provide immobilization of the ankle-foot complex and are therefore used for people with significant distal weakness and resulting medial and lateral instability of the ankle (Fig. 5-3E). However, because of the fixed ankle position, sit-to-stand transfers and climbing stairs and inclines are difficult. The angle at the ankle of a solid AFO can be set in a few degrees of plantar flexion. This modification enhances knee stability and may be useful in patients with quadriceps weakness and knee buckling. Addition of an anterior (pretibial shell) might also help to counter the tendency to knee buckling. On the other hand, setting the angle in a few degrees of dorsiflexion can help limit hyperextension at the knee (genu recurvatum). If the AFO is set in dorsiflexion, the patient must have sufficient quadriceps control to compensate for the increased knee flexion moment during the loading phase of gait. Another option for people with foot drop and/or mild quadriceps weakness is to use floor reaction orthoses (FROs) (such as the ToeOFF® braces) (Fig. 5-3F and G). FROs use ground reaction forces to offer a “push” at toe off as the orthosis dynamically unloads stored energy to assist with propulsion. This action assists with impaired ankle plantar flexion strength, which is often underdiagnosed. In addition, FROs help create a knee extension moment which may help people with weak quadriceps and a tendency to knee buckling. For patients with spasticity, additional features might be built into the AFOs including a tone-reducing foot plate, toe extensor pads, foam toe separators, metatarsal pads, sustentaculum tali lift, or a plantar flexion stop.
In addition to improving gait efficiency, AFOs can also be used at night to help to prevent or minimize progressive equinus contractures in patients with significant ankle dorsiflexion weakness or increased lower extremity tone. Nighttime AFOs can be either resting AFOs (static braces that keep the ankle aligned in a neutral position) or dynamic AFOs (which provide a low-load prolonged-duration stretch to the gastrocnemius–soleus complex) (Fig. 5-4).
Nonambulatory AFO. This AFO provides low-load prolonged-duration stretch to the gastrocnemius–soleus complex. It might be used, especially at night, to help prevent or treat ankle plantar flexion contractures (Used with permission of Aaron Norell, Orthotist and Prosthetist, Spaulding Rehabilitation Hospital, Boston, MA.)
In individuals with quadriceps weakness, a different type of brace that might be tried to provide knee stability is the knee-ankle-foot orthosis (KAFO) (Fig. 5-5). Many KAFOs are too heavy for practical use by individuals with progressive neuromuscular weakness. However, they have been successfully used in polio patients and may assist with ambulation in selected patients with other neuromuscular conditions such as IBM.