Etiology, incidence, and medical diagnosis

ALS, the most common form of motor neuron disease in adults and frequently called Lou Gehrig disease in the United States, is a relentless, degenerative, terminal disease affecting both UMNs and LMNs. The name comes from two concurrent events. “Amyotrophy” indicates the muscle atrophy and weakness resulting from massive loss of lower (α) motor neurons originating in the spinal cord and motor cranial nerve nuclei in the lower brain stem. “Lateral sclerosis” indicates the demyelination and gliosis (i.e., “scarring” with hypertrophy and a dense fibrous network of neuroglia) of the corticospinal tracts (that run laterally in the spinal cord) and corticobulbar tracts resulting from degeneration of the Betz cells (also known as pyramidal cells ) in the motor cortex, the cell bodies of the UMNs. With both UMNs and LMNs affected, people typically experience rapid degeneration, become dependent for all care, and (without mechanical ventilation) die of respiratory failure within 3 to 5 years after symptom onset. A notable exception to this rule was Dr. Stephen Hawking, who lived with ALS for over 50 years before his death in 2018, working and contributing to society even while dependent on mechanical ventilation and assistance for all motor functions.

The cause of ALS is unknown. Numerous theories have proposed genetic, infectious, environmental, and autoimmune etiologies. Some authors suggest that ALS and other neurodegenerative disorders are related to TDP-43 proteinopathy, which links ALS to frontotemporal lobar degeneration (FTD), a disease that affects cognitive function but typically spares memory. Ninety percent of cases of ALS are sporadic without a known genetic component; however, approximately 5% to 10% seem to have a complex genetic basis coded on ALS1 through ALS8 and other mutations that are associated with frontal lobe dementias. Twenty percent of genetic causes of ALS are considered to be related to mendelian mutations in the superoxide dismutase–1 (SOD1) gene (ALS1). Other factors considered in the genesis of ALS are vascular endothelial growth factors, toxicity (e.g., from heavy metals such as lead, selenium, and mercury) leading to motor neuron death, oxidative stress, and mitochondrial dysfunction related to microglial inflammation ^, and environmental factors. Controversy regarding the role of physical activity as a risk factor or a factor associated with earlier onset of ALS versus neuroprotection against ALS has evidence on both sides. Factors such as trauma and multiple traumatic brain injuries, associated with greater risk for ALS, confound the evidence regarding the association of ALS with vigorous sport activity. Some evidence indicates that ALS is the consequence of multiple interactions among these factors, and that none of them alone is the direct cause. ^,

Because ALS has no specific biomarkers identified, the differential diagnosis requires extensive work up, ruling out other possibilities and allowing time to monitor progression. Cervical or lumbar myelopathy, syringomyelia, multiple sclerosis, primary lateral sclerosis, diseases associated with LMN pathology, heavy metal toxicity, paraneoplastic syndromes, myopathies, and Lyme disease must be excluded before the diagnosis of ALS is made. Creatine phosphokinase levels are elevated in approximately 70% of patients and tend to be higher in patients with limb onset ALS rather than bulbar onset. Genetic testing to identify the mutations in the copper/zinc (Cu/Zn) SOD1 gene is available when a family history of ALS is present. Other laboratory tests, such as identification of biochemical markers in the blood and cerebrospinal fluid (CSF), are used to exclude other neurological diseases. Testing CSF may have an additional benefit. A meta-analysis of 10 articles examining elevated levels of neurofilaments (reflective of ongoing destruction of axons) in the CSF revealed a pooled sensitivity and specificity at 81% and 85%, respectively, for association with motor neuron disease (9 out of 10 articles specified ALS), indicating potential diagnostic accuracy in people already showing symptoms. Electromyography (EMG) and nerve conduction studies can be helpful to confirm the presence of widespread LMN disease (with neurogenic and fibrillation potentials and/or sharp waves) without peripheral neuropathy or polyradiculopathy. Neuroimaging studies can rule out conditions such as cervical myelopathy and myelitis that may have clinical signs similar to those of ALS. To date, while multiple laboratory tests, genetic testing, and imaging studies are performed, they are used more to rule out other possibilities than to rule in ALS.

Clinical diagnosis of ALS requires a pattern of observed and reported symptoms of both UMN and LMN disease and persistent declines in physical functions that cannot be attributed to other disorders. Because of the overlap of symptoms with other neuromuscular disorders, misdiagnosis is not uncommon. The World Federation of Neurology (WFN) has developed suggested diagnostic criteria (the El Escorial criteria, refined by the Awaji criteria to identify specific EMG interpretations), indicating suspected, possible, laboratory-supported-probable, probable, and definite ALS for patients with ALS entering clinical research trials. The categories have sometimes been simplified, labeling just three: possible, probable, and definite ALS. (The WFN ALS website [ www.wfnals.org ] provides up-to-date criteria used for clinical studies.) Essentially, a patient with “definite” ALS must show concomitant UMN and LMN signs in multiple spinal regions (regions designated as cervical, thoracic, lumbosacral) or in two spinal regions plus bulbar signs and show evidence of progression over a 12 month period. ^, The category of “possible” ALS can be interpreted as a diagnosis of ALS if progressing LMN signs are present in two or more body regions, even without UMN signs, yet apparent as long as other diseases have been ruled out; the literature suggests that UMN pathology is present before clinical signs become apparent.

ALS has an incidence of approximately 2 to 3 cases per 100,000 Caucasians, with somewhat lower incidence in Asians and African Americans. Mean age at onset is 57 years, with two-thirds of patients aged 50 to 70 years old at time of onset. Men are affected approximately 1.3 to 1.5 times more frequently than are women, although gender differences decrease with late onset of disease (aged 70+).

Clinical presentation

For an overall view of the clinical presentation of a person with ALS as categorized by the ICF model, review Fig. 15.4 . The predominant body function impairments of ALS are weakness and fatigue (affecting movement dimensions of strength and endurance ), with muscle atrophy and fasciculation indicating body structure effects on LMNs and spasticity indicating body structure effects on UMNs (see Fig. 15.1 ). Activity limitations and participation restrictions progress as the impairments of weakness and fatigue become more severe, but an individual’s clinical presentation will depend on environmental and personal factors as well, such as economic resources and coping mechanisms (see Fig. 15.4 ).

Some less prominent or prevalent body function impairments were originally thought to be exclusionary criteria for ALS: ocular motor abnormalities, deficits in sphincter control (especially bladder), sensory loss, or cognitive involvement. With longer survival facilitated by mechanical ventilation and better tools to examine pathology, these signs and symptoms are no longer considered spared, but merely resistant or delayed. For example, in a review of literature on ocular motor pathology in ALS, Sharma and colleagues speculate that the ontogenetically older and more complex pathways of the ocular motor system protect it somewhat from ALS pathology. The nuclei for cranial nerves III, IV, and VI do not receive direct monosynaptic connections from the motor region of the cortex like other motor neuron pools in the brain stem or spinal cord. Also, the predominant neurotransmitters are different (fewer glycinergic and muscarinic cholinergic receptors in the ocular motor nuclei) and the oculomotor neurons contain a higher ratio of calcium-binding proteins (important for maintaining lowering levels of intracellular calcium, thought to be a source of excitotoxicity in ALS) than in motor neuron pools typically affected in ALS. In addition to ocular motility, signs of neurogenic bladder have been reported in about 40% of patients, and progressive functional deficit in sensation have been recorded in ALS, perhaps related to ongoing immobility.

Similarly, cognitive deficits have been noted in ALS. A small subgroup of patients with both familial and sporadic forms of ALS has been identified as having concomitant evidence of FTD, with pathology in cortical areas outside of the cortical motor regions. These patients show lower scores on executive cognitive functions, word finding, and phrase length. As people can exhibit a combination of ALS and FTD, the evidence suggests that a common cause may be possible. Because of these findings, therapists should be aware of the possibility of cognitive deficits in their patients with ALS, manifested as a decrement in planning, organization, and language problems. Such patients may have more difficulty following through on medication and therapeutic recommendations, and their families may need more support. Unassociated with overall cognitive impairment, some deficits in action knowledge as opposed to object knowledge have been noted in patients with ALS, correlating with atrophy in the motor and premotor cortex.

Although impaired strength and endurance predominate in ALS, the appearance of weakness (paresis to paralysis) and fatigue are heterogeneous. Some people have limb (spinal) onset; others have cranial nerve (bulbar) onset. Many start with a single limb involved (flail arm or flail leg) at first, with different neural roots and nerves affected within that limb. Some may present with progressive muscular atrophy (LMN predominant); others present with primary lateral sclerosis (UMN predominant). During initial diagnostic visits, patients frequently report to their physicians a profound sense of fatigue or the loss of exercise tolerance. Because the onset of ALS is insidious, most patients are not aware of the strength changes, or they have adjusted to the changes until they have difficulty with a functional activity such as tying shoes, climbing stairs, or stumbling with a fall. Physical examination usually demonstrates more widespread and extensive weakness and atrophy than reported by the patient. By the time most patients report weakness, they have lost approximately 80% of their motor neurons in the areas of weakness. Relative preservation of function despite so much tissue damage demonstrates both the reserve and the plasticity of the nervous system (or the mindset of the individual patient who delays reporting changes) in the drive to adapt to meet functional goals. As the disease progresses, weakness spreads to include musculature throughout the body.

ALS progression varies with several distinct patterns according to the primary area of onset. Lower-extremity onset is slightly more common than upper-extremity onset, which is more common than bulbar onset. With leg onset, the next area of symptoms tends to be the contralateral leg, then the ipsilateral and contralateral arm before bulbar symptoms appear, especially if a distinct indication of both UMN and LMN disease is present ( Fig. 15.5 ). A significant diagnostic feature of the pattern of disease is the asymmetry of the weakness and the sparing of some muscle fibers, even in highly atrophied muscles. For example, a patient may have weakness of the right intrinsics and shoulder musculature or weakness of the left anterior tibial muscles. Bulbar symptoms are presaged by tongue fasciculations and weakness, facial and palatal weakness, and swallowing difficulties, which result in dysphagia and dysarthria. Table 15.1 lists bulbar and respiratory impairments and activity limitations in ALS. Pseudobulbar signs (sometimes referred to as pseudobulbar palsy or affect) are sometimes present in ALS, manifested by exaggerated laughing or crying beyond what seems to be appropriate to the situation. Despite the pattern of onset, the eventual course of the illness is similar (with variations in timing) in most patients, with an unremitting spread of weakness to other muscle groups leading to total paralysis of limb, trunk, and diaphragm musculature and muscles innervated by the cranial nerves. Death is usually related to respiratory failure, occurring within 3 years of symptom onset in approximately 50% of patients. With mechanical ventilation, up to 10% of people with ALS live longer than 10 years.

Possible Pattern of Degeneration in Amyotrophic Lateral Sclerosis.

(A) Onset in cortex or spinal cord; (B) interhemispheric and interneuronal connections in the cortex and spinal cord spread the disease from the site of onset to contralateral motor neurons; (C) degeneration continues in areas adjacent to sites of onset, affecting additional muscles in the same limbs and in additional regions. (Figure from Walhout R, Verstraete E, van den Heuvel MP, et al. Patterns of symptom development in patients with motor neuron disease. Amyotroph Lateral Scler Frontotemporal Degener. 2018;19:21–28.)

Once ALS has been diagnosed, knowing the natural history of the progression of ALS should help in the institution of medical and supportive treatment planning and interventions. Disease-specific standardized scales have been developed that help chart the course of ALS. Hillel and colleagues developed the ALS Severity Scale (ALSSS) for rapid functional assessment of disease stage. Their ordinal scale allows clinicians and therapists to score patients in four categories, with 10 points possible for each: speech, swallowing, and lower-extremity and upper-extremity function ( Box 15.1 ). A multistage scale of severity has also been proposed based on milestones common among 1471 patients with ALS in one treatment center. Patients in stage 1 (mild disease) have symptom onset, with noticeable or functional involvement in one region (bulbar, upper limb, lower limb, or diaphragmatic); at stage 1, individuals are functionally independent in ambulation, activities of daily living (ADLs), and speech. Stage 2a is when most people get diagnosed; stage 2B is when a second region shows clinical involvement. Stage 3 is when a third region is involved; the patient has (moderate) deficits in function in three regions or a moderate to severe deficit in one region and mild functional loss in two other regions. Stage 4A indicates need for gastrostomy because of eating difficulties; 4B indicates need for respiratory support (usually noninvasive ventilation). The ALS Functional Rating Scale (ALS FRS) and the ALSFRS-Revised consist of 13 items with response options of 0 (unable) to 4 (normal performance) that assess how well people are functioning across various systems; this scale is frequently used clinically and in clinical trials to document status and changes ( Box 15.2 ). Mitchell and Borasio provide more information on the natural history of ALS.

Along with the primary impairments of weakness and fatigue affecting body structure and function in ALS, patients also have progressive limitations in activity and participation. Activity limitations result in gradual loss of independence in community and then household tasks. Mechanical and electronic adaptive devices can help extend independence in some ADLs past the initial strength losses. Participation limitations result in progressive isolation from the community and family unless extraordinary efforts are made to implement an evolving communication system, usually using electronic interfaces.

Medical prognosis

In almost all cases ALS progresses relentlessly and leads to death from respiratory failure. The rate of progression seems to be consistent within each patient but varies considerably among patients. Patients with an initial onset of bulbar weakness (dysarthria and dysphagia) and respiratory weakness (dyspnea) tend to have a more rapid progression to death than patients whose weakness begins in the distal extremities. Reports vary in terms of long-term prognosis, depending on medical care and choices regarding mechanical ventilation, but death usually follows within 2 to 4 years after diagnosis. Diagnosis is often delayed 1 to 2 years after the onset of symptoms when the clinical presentation of symptom progression is recognized by a physician. A small number of patients live for 15 to 20 years.

Years of survival after diagnosis may change as drug therapies are developed. In addition, increasing numbers of patients are electing to prolong life with home-based mechanical ventilation as opposed to palliative or comfort care only.

Medical management

ALS has no known cure and few effective disease-slowing treatments. Mitchell and Borasio summarize the results of trials of many putative ALS-modifying pharmaceuticals. Riluzole has the longest history as an approved treatment of ALS. Riluzole, a glutamate inhibitor, provides very modest improvement over a placebo in both bulbar and limb function, but not in actual strength of muscles. According to meta-analyses of randomized controlled trials (RCTs), riluzole extends life-span an average of 2 to 3 months. The side effects were minimal in some studies, but fatigue and weakness have been noted in 26% and 18% of patients taking riluzole compared with a placebo. In 2017, the Federal Drug Administration (FDA) approved the use of edaravone, a free radical scavenger, in the early disease stages of ALS; further research is needed to determine whether this drug is associated with improvement in quality of life.

Animal studies reveal some promise. In a mouse model of ALS, cell-therapy researchers targeted both the motor neurons and astrocytes and the microglia that surround them, noting an additive effect on life-span and motor function. This study confirms that the pathology in the genetic strains of ALS stems from both the mutant gene expression in motor neurons and in the hostile cellular environment provided by the microglia. Unfortunately, the study of animal models may relate to the genetic forms of ALS (about 10% of cases) but does not translate well to the sporadic forms. A 2016 Cochrane review of cellular treatments in humans with ALS found no completed RCTs, although several trials were under way. Jaiswal in 2017 highlighted the promise of stem cell research for humans: induced pluripotent stem cells can be prepared in vitro to differentiate as motor neurons with ALS, to create “disease in a dish.” Microglia and astrocytes can also be created. With substantial amounts of human cells to work on, promising replacement cellular therapies can be tried, repeated, and modified before in vivo trials begin.

The popular press has reported on nutritional cures for ALS, including regular use of vitamin E. However, Orrell and colleagues found insufficient evidence to support clinical use of vitamin E supplements in ALS as an additive to riluzole treatment or as adjunctive therapy, although no apparent contraindication was found to taking the supplement. Vitamin D supplementation was associated with a reduction in functional decline in preliminary studies. Other nutritional and nonpharmaceutical supplements have had some success in animal models of ALS, but this has not yet been confirmed in humans.

Cannabis has been studied for its effect on spasticity in patients with multiple sclerosis and spinal cord injury, but evidence in ALS is limited. In a study of 131 people with ALS, 13 used cannabis, with reports of reduction in spasticity, pain, and depression. A systematic review cites moderate-quality evidence indicating that tetrahydrocannabinol (THC) is probably ineffective in reducing muscle cramps in ALS. As with many other approaches, more high-quality research is needed.

Because of the apparent hopelessness of the diagnosis, many physicians, especially those not associated with major medical centers having neuromuscular disease units, do not refer patients with ALS for rehabilitative or support services. However, few primary care physicians or neurologists have extensive experience in the care of patients and families coping with ALS because of the low incidence of the disease. Referral of patients with ALS to a multidisciplinary clinic typically extends the patient’s life-span, especially patients with bulbar onset of ALS. ^{, ,}

Although the overall disease course has not been halted, several specific impairments have been addressed through medical and pharmaceutical interventions. The following subsections discuss medical management of muscle spasms and pain, dysphagia, dysarthria, and respiratory dysfunction.

Respiratory management

Respiratory failure is the primary cause of death in patients with ALS. Progressive respiratory failure is related to primary diaphragmatic, intercostal, abdominal, and accessory respiratory muscle weakness (see Table 15.1 ). Respiratory failure should be anticipated and discussed early following the diagnosis of ALS (as patients and families are ready), so that patients and their caregivers can express their wishes and develop an advanced directive for care in the terminal phase of the disease.

Physiological tests used to indicate respiratory dysfunction include vital capacity (VC), sniff nasal pressure, maximal inspiratory pressure (MIP), and nocturnal oximetry. VC (commonly reported as percentage predicted) has been measured in various ways; measuring slow vital capacity (SVC, recording volume upon slow exhalation after maximal inspiration as opposed to forced vital capacity [FVC] that requires fast and effortful exhalation) has been advocated in ALS because it requires less effort and thus can continue to be assessed through more of the disease process. However, FVC remains the usual indicator of the need for ventilation: when the measure drops below 75% (of normal expected) FVC, the individual should be monitored for respiratory failure; 50% (of normal expected) FVC indicates need for ventilatory assistance. Some researchers have explored instituting assisted respiration intermittently at earlier stages (77% FVC). Clinical signs of increased respiratory dysfunction are dyspnea with exertion or lying supine, hypoventilation, weak or ineffective cough, increased use of auxiliary respiratory muscles, tachycardia (also a sign of pulmonary infection with fever and tachypnea), changes in sleep pattern, daytime sleepiness and concentration problems, mood changes, and morning headaches.

In early stages of patient care, physical therapists (PTs) may help manage respiratory dysfunction by providing postural drainage with cough facilitation (suctioning if necessary), especially during acute respiratory illnesses. The patient and care providers should also be taught breathing exercises, chest stretching, and incentive spirometry techniques, as well as postural drainage techniques if the caregivers are prepared to provide such support. Although breathing exercises consisting of resisted inspiratory muscle training can facilitate functional respiration, even practicing unresisted breathing for 10 minutes three times a day has been shown to result in improved function. Breathing techniques such as diaphragm training have shown little benefit, perhaps because patients have difficulty changing their pattern of breathing even with the training. Overall, inspiratory muscle training in ALS, although showing some effect on survival time in one out of the four studies reviewed, requires further research with standardized protocols and timing. An assessment of the home environment is imperative to identify sleeping positions and energy conservation techniques that can make breathing easier and be incorporated into the patient’s daily life.

As respiratory symptoms increase, some advocate the intermittent use of oxygen at 2 L/min or less; the down side of supplemental oxygen is possible suppression of the respiratory drive with potentially poorer outcomes. When hypoventilation with a decline in oxygen saturation becomes common during sleep, resulting in morning confusion and irritability, patients have the option to initiate use of noninvasive, intermittent positive-pressure ventilation (abbreviated NIV or NIPPV). NIV provides greater inspiratory than expiratory pressure to decrease the effort of breathing, and can be administered by mask, contoured nasal delivery systems, or a mouthpiece interface ( Fig. 15.6 ). Some evidence indicates that early use of NIV can increase survival time by several months and increase quality of life. Moderate-quality evidence indicates that the length of survival with NIV depends on bulbar function: if bulbar function is less than moderately impaired, median additional days was 205; if bulbar function is poor, NIV neither prolongs survival nor improves quality of life, although sleep function may improve. When a patient can no longer benefit from NIV, a decision must be made about initiating invasive ventilation by tracheostomy or to switch to palliative care. (See also Miller and colleagues for a discussion of practice parameters in the decision making process related to ventilatory support.) Although in the initial stages of ALS most patients indicate they would not want prolonged ventilator dependence at home, patients may change their minds as they adapt to the disease restrictions or they and family members may retain hope for the future despite functional losses. A small study of patients who started tracheostomy intermittent positive-pressure ventilation (TIPPV or TIV) demonstrated increased long-term survival (2 to 64 months). In another series of 70 patients on long-term TIPPV, 50% of the patients were living after 5 years; however, 11.4% of these patients had entered a “locked-in” state. Decisions about long-term ventilator use should be made by the patient and involved family members or partners, with input from the interdisciplinary team caring for the patient. Discussions of preferred long-term care options should be revisited as the patient’s condition changes.

Example of Mouthpiece Ventilation Interface for Noninvasive Ventilation.

(A) Mouthpiece, flexible tubing, mechanical ventilation unit; (B) patient with amyotrophic lateral sclerosis using mouthpiece interface for noninvasive ventilation (NIV) during the day. This patient requires NIV 24 hours a day. He uses a nasal interface at night. (From Garuti G, Nicolini A, Grecchi B, et al. Open circuit mouth-piece ventilation: concise clinical review. Rev Port Pneumol. 2014;20:211–218.)

If a patient decides that home ventilation is a reasonable option, those involved in the decision might benefit from visiting another patient who is using in-home mechanical ventilation (HMV). Because the decision for home mechanical ventilation (HMV: NIV or TIPPV) also affects the life of the patient’s spouse, children, and extended family, who may be responsible for some aspects of home care or whose lives may be affected by the presence of in-home nurses or attendants, the decision for HMV should not be taken lightly. Extensive preparation, ongoing support, and respite options for caregivers are necessary if HMV is to be successful. Success of HMV also depends on such variables as third-party payment for home care equipment and nurse or attendant staffing, working status of the partner or spouse, age and physical fitness of the spouse and children, pre-ALS family psychosocial interactions, and financial factors. HMV should be viewed as long term, often extending for more than 1 year. Initiation of HMV results in a reasonable perceived quality of life for the patient, yet caregivers report that their quality of life may be lower than the patient’s because of the burden of care that must be provided.

With chronic respiratory insufficiency, the patient and family must be involved in the long-term care decisions related to instituting mechanical assistance (invasive ventilation) under either emergency situations or in response to gradual deterioration. This discussion should occur before respiratory failure develops in patients. Acute respiratory failure can happen quickly and is generally frightening; few patients or family members are prepared to forego intubation and artificial ventilation during the emergency unless they have settled the issue early. Patients and caregivers should understand that not making a decision about mechanical ventilation, noninvasive or invasive, is a decision to support mechanical ventilation.

Physicians and health care workers who work with the patient and family must be aware of their own feelings and beliefs about prolonging life and the value of quality of life. For example, a healthy physician or therapist who values control and an active lifestyle may envision a life on a ventilator as intolerable and pass that value on to the patient, who may or may not have the same needs. The patient’s decision, or change in decision, must be respected by the medical team involved in care. In medical centers that use a team approach, patients and families may find support by meeting with counselors or peers with ALS who are making or have made decisions about long-term ventilator care.

Therapeutic management of movement dysfunction associated with amyotrophic lateral sclerosis

Perhaps because of the multitude of issues to consider when managing the impairments and limitations associated with ALS, evidence suggests that patients treated by a specialized ALS multidisciplinary team (typically including physician, PT, occupational therapist, speech language pathologist, respiratory therapist, nurse coordinator, and social worker) fare better than do those treated by single-source providers, or general neurology clinics. One study reported a 2-year postdiagnosis mortality rate of 24% with multidisciplinary care compared to about 50% after 18 months in historical controls. However, a systematic review of the evidence for multidisciplinary care advantages in this population concluded that the evidence is of low quality, so far, with no controlled trials identified as of 2017. Whether administered through an ALS-specific multidisciplinary team or not, therapeutic management will necessitate examination of the patient’s current status, evaluation of the deficits in relation to patient preferences and needs, and establishment of a plan based on mutually determined and realistic goals. In addition to the team members listed previously, the plan may eventually involve nutritionists, orthotists, pulmonologists, gastroenterologists, assistive technology experts, home modification/designer experts, psychologists, and palliative-care providers.

The rate of the patient’s disease progression, the areas and extent of involvement, and the stage of illness must be considered. A patient at the initial stages (independent) will have different needs than a patient at later stages (dependent) whether or not the patient has chosen to have assisted ventilation. NIV or tracheostomy ventilation may extend life-span, but typically individuals have a markedly reduced mobility level. The goal at all stages is to focus on what the patient needs to optimize health and increase quality of life. With guidance and environmental adaptations, patients with slowly progressing weakness may be able to continue many of their ADLs for an extended number of months or years. In the final stages of the disease, when the patient is bedridden, programs to increase long-term strength or endurance evolve into programs to improve patient-caregiver communication and handling for daily tasks. At this stage, interventions such as stretching may not effectively control contracture development. However, patients who are dependent on all mobility may still benefit from positioning and ROM exercises to decrease muscle and joint pain related to immobility. The prescription of assistive devices and training of caregivers will be needed through much of the final stage. The efficacy of therapeutic interventions will be related to the timing of interventions, the motivation and persistence of the patient in carrying out the program, and support from family members or caregivers. Objective documentation using standardized outcome measures will help justify the usefulness of therapeutic interventions at each stage of this disease. For examples of rehabilitation team roles at three different stages of ALS, see the review with case studies by Majmudar and colleagues.

Assessment

Rehabilitation professionals specifically address body function impairments, activity limitations, and participation restrictions related to ALS (see Fig. 15.4 ), along with environmental and personal factors, using standardized measures where possible.

The extent of the therapeutic assessment by any one rehabilitation professional will depend on whether the clinician is working as a member of a rehabilitative team or as an independent or clinic-based therapist receiving a referral to evaluate and treat. PTs and OTs working as team members may have a more circumscribed role related to gross motor function and ADLs, with other consultants focusing on bulbar, respiratory, and environmental adjustments. The therapist working in a facility without a neuromuscular disease clinic or in a community or rural environment, however, should be aware of the need to carry out a broad-based assessment. In addition to standard neuromuscular, musculoskeletal, and functional-level examinations within the specific discipline of PT or OT, the therapist should also evaluate the patient’s stated or observed functional problems relative to bulbar and respiratory impairments, environmental barriers to independence, and caregiver education.

If possible, before the patient’s initial visit, the therapist would benefit from contacting the patient and requesting that he or she keep an activity log for several days. If an early contact is not possible, the therapist can assign that task during the initial session. The log should include 15-minute time increments in which the patient or caregiver can record what she or he was doing during a specific period. The log should also indicate whether the patient was experiencing fatigue or pain during the activity and how the patient perceived her or his respiratory status. An example of a completed activity log is shown in Fig. 15.7 . The patient’s sense of fatigue with repetitive muscle activity or functional tasks should be specifically tracked.

Example of a Log for Monitoring Activity Level of Patients With Amyotrophic Lateral Sclerosis.

Primary deficits.

Weakness and fatigue will be the primary deficits (see Fig. 15.3 ), with spasticity or other problems following depending on the location of strength loss. Muscle weakness and the experience of fatigue will require separate measures. In the literature, strength has been assessed with manual muscle testing (MMT) or maximal voluntary isometric contract (MVIC) against a strain gauge or dynamometer. Multiple muscles may be tested by uniformly trained therapists and averaged together using MMT numbers along with minus and plus scores (e.g., 4−, 4, 4+) to convert scores to a 0 to10 scale; the result is both reproducible and sensitive to change in ALS. Equally reproducible is the Tufts Quantitative Neuromuscular Evaluation (TQNE) that measures muscle strength of 10 muscle groups bilaterally using standardized positions and a strain gauge or dynamometer, along with pulmonary function and timed motor tasks. The TQNE provides reliable measurement but requires large equipment space and frequent position changes, which can be very resource intensive and fatiguing for patients. For testing of single muscles or a few muscles to determine change with intervention, a quantitative measure is recommended, such as hand-held dynamometry testing or grip or pincher strength testing, with standardized protocols to maximize reliability.

Fatigue may occur at any stage, whatever the patient’s strength or physical capabilities. Fatigability is typically greater in people with ALS than without ALS, and can be assessed with a Rate of Perceived Exertion (RPE) scale following activity, the change in maximal strength produced (dynamometer recording or MVIC) after strenuous activity, or the deficit in number of meters walked in minute 6 versus minute 1 of a 6-Minute-Walk-Test (6MWT). Perception of fatigue can be assessed using self-report measures such as a visual analogue scale for fatigue (VAS-F) or questionnaires covering different dimensions of fatigue such as the Fatigue Severity Scale (FSS).

Initial examination.

A typical initial examination of a patient’s movement and function includes the following components. Different rehabilitation personnel will target this list depending on the standards of their discipline, such as the comprehensive list of examination components in the Guide to Physical Therapist Practice. Considerations specific to an examination in ALS are shown in Box 15.3 . The extent of the examination in any one session depends on the patient’s condition and the patient’s or caregiver’s ability to participate.

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  Patient History. The chart review or history should extract the patient’s medical and activity records, especially time since diagnosis, time course, and rate of disease progression to date, current medications, concurrent medical issues, current activities and participation, and any symptoms related to them. The history should focus on current and recent activities and participation signifying patient’s lifestyle, ADL tasks, hobbies or interests, and work focus; primary complaints, including weakness, fatigue, muscle spasms, pain, respiratory status, safety, or speech and swallowing issues; psychosocial support issues (family, caregivers, and agencies); the patient’s and family members’ understanding of ALS and the likely progression and prognosis; and the patient’s current concerns and goals. This last item is critically important: the focus of attention should be on the patient’s and family’s current concerns and goals, rather than on the therapist’s knowledge of issues expected in the future.

  
  
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  Systems Review. Screening for multisystem involvement should include checking vital signs at rest, skin integrity, bony abnormalities, sensory integrity, communication ability, and the ability to follow multistep commands. Cognitive screening may include measures such as the Mini-Mental Status Exam (MMSE) because of the possibility of ALS-FTD. When gross screening shows systems with deficits, more extensive examination may be indicated, or the patient may be referred to appropriate health care professionals.

  
  
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  Tests and Measures. Body functions to be tested include movement ability (with attention to the six dimensions of movement appropriate to the region of the body with deficits), pain, cognitive function (if needed), and specific impairments such as dysarthria, dysphagia, and respiratory function. Measures should also be used to document relevant activity limitations, participation restrictions, and environmental and personal factors affecting function at the current stage of the disease process. Any Clinical Practice Guidelines regarding core sets of outcome measures should be followed as appropriate. Tests and measures generally include:

  
  
  
  
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    Baseline testing of muscle strength (MMT or hand-held dynamometer testing, grip strength, 5 times sit-to-stand test—also used to assess transfers), endurance (6MWT, time tolerating activity, self-report questionnaires for fatigue), flexibility (ROM, muscle tone), speed (timed tasks), and accuracy and adaptability as needed. Therapists may observe and document any areas of atrophy or fasciculations.

    
    
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    Assessment of functional activity level (using a standardized test or assessment tool whenever possible) to include, as appropriate: transfers, gait, upper-extremity function, postural control, eating, toileting, and assistive devices. Suggested tools include the ALSFRS-R, the ALSSS, timed walk test (25-foot walk test or 10-m walk test), Timed Up and Go test, 6MWT, and 9-Hole Peg Test. Of the generic walking measures, the 6MWT has been validated in ALS. Although weakness may affect balance during gait, patients with ALS have not shown deficits in postural control during quiet stance despite significant paresis or tone changes, possibly because sensation is relatively preserved. However, generic postural control tools may be useful, such as the Berg Balance Test (when the patient can stand dynamically) or the Function in Sitting Test (when standing is no longer possible but unsupported sitting is available). The Barthel Index or Functional Independence Measure (FIM) could be used for testing of independence in ADLs.

    
    
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    Documentation of pain (onset, type, site, and intensity; use body chart and subjective pain scale); identify what makes pain worse or better. Sensory testing may also be required.

    
    
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    Assessment of bulbar and respiratory function (review Table 15.1 ). Perform cranial nerve screening tests; observe facial, lip, tongue, and jaw movements; look for atrophy or fasciculations in the tongue; and palpate muscles of mastication. Document breathing patterns at rest and with exertion; listen to breath control during speech. For an in-depth evaluation of bulbar function, the patient should be referred to an ear, nose, and throat clinic, speech-language pathologist, or communications disorders clinic, unless full evaluation is available in a comprehensive ALS clinic.

    
    
  • •
    

    Assessment of quality of life or subdimensions such as sleep, well-being, and life satisfaction using generic measures that have been validated in other neuromuscular populations. The Nottingham Health Profile and SF-36 have been recommended in this population.

    
    
  • •
    

    Assessment of the patients’ environment with a focus on energy conservation and safety at current and future functional capabilities. Assessment of adaptive equipment needs and modifications. Documentation of personal factors (motivation and coping skills) affecting function and availability of psychosocial support is especially necessary as the disease progresses.

  
  

BOX 15.3

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