Upper Extremity Function in Multiple Sclerosis
Christine Smith and Kathleen M. Zackowski
KEY POINTS FOR CLINICIANS
• Upper extremity (UE) dysfunction is a common issue for individuals with multiple sclerosis (MS).
• Adequately measuring and treating UE dysfunction is critical for improving function in MS.
• Areas of assessment of the UE which should be considered include strength, sensation, coordination, manual dexterity, and range of motion.
• An occupational therapist can work with individuals to help them maintain their independence and participation in daily tasks and as well as reduce the effects of disability caused by the symptoms of MS.
• Patient/caregiver education is paramount in the successful management of UE dysfunction.
UE dysfunction is a common yet often overlooked issue for individuals with MS. In a study by Kister et al. (1), 60% of participants reported that impaired function of the hand was the most frequently reported symptom in the first year of the disease. UE dysfunction may be present in up to 80% of individuals with MS, yet it is frequently not addressed in the clinical setting (2). This is at least in part due to the weight placed on ambulation and lower limb dysfunction in clinical rating scales such as the Kurtzke Expanded Disability Status Scale (EDSS) (3,4). Dysfunction of the UE is multifactorial, including weakness, spasticity, ataxia, tremor, sensory loss, and pain. When faced with one or more of these symptoms, individuals with MS often present with difficulty performing their activities of daily livings (ADLs) due to the primary or secondary symptoms that affect UE movement and coordination.
It has been shown that the degree of UE dysfunction correlates to an individual’s level of independence, negatively impacting quality of life (5). These difficulties may arise even in the initial time following a diagnosis of MS. MS symptoms change with time, affecting the unique capacity each person has for activity and participation. Symptoms fluctuate due to exacerbations or they can progressively worsen without fluctuations, and this occurs amid changing demands due to age and personal circumstances (i.e., the need to work, care for kids, make meals, drive, etc.). People with MS can have one or both UE affected, and to different degrees of severity. This clinical heterogeneity limits the effectiveness of a standard intervention and highlights the need for client-centered interventions. Often, it is difficult to ascertain the root of the dysfunction as it can be due to impairments of the motor system, sensory system, or a combination of the two. Accurately measuring and treating UE dysfunction is of critical importance for improving function in MS. However, the UE is involved with complex multidimensional tasks (e.g., reaching, grasping, stabilizing the body, and manipulating objects); therefore, it is important to consider several issues before assessing or treating dysfunction. A primary issue is that there are a wide variety of UE assessment measures to choose from, many of which are ordinal in nature and consequently are broad and not well defined for detection of subtle deficits (e.g., EDSS). A second issue is that assessment measures are often most sensitive within a particular window of disability; therefore, one assessment measure may not be appropriate throughout the disability continuum. A third problem is that people with MS typically have multiple symptoms and these combinations 233make it difficult to determine the best choice of intervention to target their symptoms and improve disability. There is currently no cure for MS, and thus rehabilitation for symptom management is a viable choice to maintain and improve UE functional status.
Identifying symptoms and quantifying their severity as well as their impact on function is essential to medical management. Areas which should be considered include strength; sensation; coordination; manual dexterity; range of motion of the shoulder, elbow, wrist, and finger joints; and endurance and sustained activity (2). Accurate evaluation and effective rehabilitation for people with MS is challenging. In this chapter, we discuss some of the causes of UE dysfunction as well as provide rehabilitation strategies which can be used to address them. Rehabilitation strategies will include direct intervention to improve function and decrease symptoms as well as compensatory strategies to maximize independence in ADLs.
SPASTICITY IN UE MS AND ITS IMPACT ON FUNCTION
Spasticity, often described as stiffness, is a common and often challenging problem in individuals with MS. Spasticity is defined by Lance as “a motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyper-excitability of the stretch reflex” (6). The symptoms of spasticity, a component of the upper motor neuron (UMN) syndrome, can vary widely from one individual to the next and can fluctuate within that individual over the course of the day. UMN symptoms can range from mild stiffness or muscular tightness to painful spasms, weakness, and lack of dexterity. While spasticity is more commonly noted in the lower extremities, it can present in the UEs as well (7). Musculature from the shoulder girdle distally through the digits may be impaired causing interference in the ability to complete daily activities such as opening containers, shampooing hair, handling medication, freely utilizing smartphones, and managing fasteners on clothing.
Spasticity can lead to both body function and structure alterations (impairments) and activity limitations if not well managed. Some alterations of body function can include muscle shortening or soft tissue contractures, which can diminish an individual’s ability to complete purposeful movements and engage in everyday tasks as well as increase the risk of developing skin breakdown and ulcers. These issues can lead to an individual experiencing poor self-esteem or poor body image. Additionally, increased spasticity can set in motion limitations to activity and participation in activities such as driving, eating, or using a keyboard. Reduced intimacy with a partner and social isolation are also factors to be considered when an individual is dealing with increased spasticity. This being said, in other people a certain amount of spasticity can be functional, affording necessary stability to maintain the capacity to complete various ADL such as using an affected hand as a stabilizer when opening a zippered bag. Regardless of whether the spasticity is functional or detrimental, when spasticity is present it means that an individual requires additional effort to complete their ADL, which leads to increased fatigue over the course of the day.
Unmanaged upper extremity spasticity can lead to increasing functional limitations in individuals with MS.
In the presence of noxious stimuli, spasticity can worsen. These stimuli can include increased core temperature, pain/discomfort, skin breakdown, or infection. Individuals with MS, as well as all members of the health-care team, need to be aware of this so when a change from typical presentation of spasticity is noted these factors can be considered and appropriately addressed.
Assessment of UE Spasticity
Assessment of UE spasticity should not only include addressing the fundamental symptoms of the spasticity but consideration should also be given to the concerns of the individual and their caregivers towards the changes to quality of life and participation in meaningful activities. The clinician should consider the significance, not the severity of the spasticity when working with individuals to establish an appropriate treatment plan.
Two commonly used tools to measure spasticity through clinical evaluation are the Ashworth (Modified Ashworth) Scale and the Tardieu (Modified Tardieu) Scale (8–11). Both of these tools measure resistance during passive soft tissue stretching. Neither of these techniques incorporates the patient’s experience of spasticity, nor how it affects their daily lives. There are also self-report measures of spasticity and they include the Numeric Rating Scale of spasticity, the MS Spasticity Scale-88, and the Spasm Frequency scale that have been used to ascertain the effects of spasticity on an individual’s function (12–14).
Assessment of spasticity should incorporate standardized tools and a measure of the patient’s experience.
Treatment of UE Spasticity
Spasticity in and of itself is not the reason for providing treatment. Addressing someone’s spasticity often occurs when the spasticity is at the level where it begins to affect 234functional abilities or if there is pain associated with the spasticity that requires intervention. It is this impact on a person’s well-being that drives the need for treatment. When intervention is considered, it is imperative to recognize that the decrease in spasticity may change the individual’s ability to complete functional tasks and this must be weighed against the benefit of decreasing spasticity. A team approach between the patient, caregivers, and the health-care team provides an effective treatment approach as both pharmacologic and nonpharmacologic approaches can be utilized as a part of a well-rounded treatment plan.
Focal spasticity in the UE can be treated effectively with botulinum toxin injected into specific muscles; this can then be coupled with splinting as needed to provide successful muscle relaxation and prevention of contractures (15). Figure 26.1(A–D) shows examples of how spasticity may appear in hand and arm. Flexion contractures are common in the fingers, wrist, and elbow joints. Using orthoses or braces will help to maintain a functional or natural position of the treated UE. Numerous prefabricated splints are readily available; however, an occupational therapist can fabricate static, static-progressive, or dynamic splints that provide a customized support tailored for the specific needs of the individual.
Stretching and range of motion exercises are integral portions to any treatment plan for spasticity, as they can minimize muscle shortening that is associated with spasticity. Stretching can be performed independently by the individual who has MS or it can be provided by a caregiver. For optimal effect, stretching must be performed daily. A stretch must be sustained in order to impact spasticity; some practitioners suggest holding a stretch for greater than 1 minute, while others suggest that a prolonged stretch (hours) must be maintained by using a splint or a brace (Consortium of MS Centers clinical practice guideline on Spasticity 2005) (16).
Whatever the treatment approach, patient/caregiver education is paramount in the successful management of spasticity. Individuals need to be independent in their home exercise program in order to improve adherence to the program.
235UE WEAKNESS IN MS AND ITS IMPACT ON FUNCTION
The clinical manifestations of muscle weakness are a primary symptom of MS. Weakness is a clinically distinct impairment that can affect arm and hand function and the performance of ADL. Although most studies of weakness in MS focus on lower extremity limitations recent studies show that weakness of the UE is also very common in people with MS. One study shows that 60% of individuals with MS report weakness of their hand or arm (1). Grip strength, for example, in healthy adults has been shown to be a predictor of health status, functional independence, and increased morbidity and mortality (17,18). The impact of muscle weakness on physical functioning is substantial, leading to difficulty with walking, balance, dexterity, grip, and arm function.
Weakness can vary among individuals with MS, ranging from very mild to severe and even leading, in extreme cases, to a fully flaccid extremity(ies), though typically this type of extreme weakness occurs after 10 or more years of having MS symptoms. The muscles affected by MS can also vary. Individuals may have weakness in individual hand muscles only, or solely in proximal arm muscles on one side, or bilaterally. Weakness in individual hand muscles can cause functional limitations in tasks such as typing, writing, or playing an instrument, thus affecting a person’s work performance. By contrast, weakness in larger arm muscles may cause difficulties with gross motor tasks such as carrying things, cleaning, or driving. Weakness is often reported as a feeling of heaviness in the limb or in terms of slowed movement, making it difficult to move quickly and accurately to complete fine or gross motor tasks. In addition to weakness, an individual may experience sensory changes in their arm that result in tingling or a feeling of numbness that varies by the time of day, and further impedes function. An individual may report, for example, that getting dishes down from a shelf is more difficult after a long day of work, so much so that he/she will stop and rest for a minute before getting the dishes down. These small events are often hardly noticed at first, but typically become more frequent and worsen over time and patients may not begin telling a clinician until they are affecting function on a regular basis. Some patients describe having cramping or moments of dystonic posturing of the hand or arm after completing a particularly strenuous task. These types of symptoms may be exacerbated by weakness even if they are not the primary cause of the weakness. It is important for clinicians to be aware of and ask about function so as to determine if strength is the impairment that needs to be addressed. Individual descriptions of weakness are important to listen to as they typically indicate what type of functional loss the individual is experiencing, and can be informative for goal setting. Be sure to ask the patient questions beyond what is required for their job, including questions about home chores, child care, and recreational activities. Weakness in a person with MS may not be obvious when observing an individual in a clinic, but becomes clear when accompanied with fatigue or when something has to be done quickly or accurately. Overall activity levels change dramatically in many people from morning to night, especially after a busy day.
Weakness rarely comes in isolation, and the combination of symptoms contributes to impaired function.
In addition to the functional impact of weakness, the location and severity of weakness may progress over the course of the disease. As with so many symptoms, muscle weakness does not follow a typical pattern but may increase in severity and functional impact over time. Lower and UE muscles may show symptoms on the right or left or both sides of the body. Goal setting is an important part of the process of identifying what is important to the patient and how it will be addressed. The patient and caregiver should both be consulted during this process. It is important to determine, for example, whether the patient is primarily interested in modifying bathing tasks or if the patient really enjoys painting and this can be a focus to achieve improvements in both areas. Being aware of the often competing needs of the patient and caregiver is critical for goal making and for decisions on what tools are best for assessment and intervention.
Assessment of UE Weakness
Assessment of UE muscle weakness should focus on appropriate measurement of muscle strength and the functional impact that weakness has on the individual’s ADL and participation in meaningful activities. Assessments used should be responsive to muscle weakness as well as reliable and valid in MS.
Two commonly used tools to measure weakness are Manual Muscle Testing (MMT) and Dynamometry. Both tools are specific for measuring the amount of resistance a person can produce against a known force. Neither of these tools evaluates the effects of weakness on an individual’s activity or participation in real-life tasks. Patient reported outcomes and timed functional task tests are most commonly used to assess overall UE function. There are no functional tasks that specifically measure how strength alone impacts function; however, the effect of weakness on self-care activities is discussed in the section titled UE Coordination and its Impact On Function.
The MMT scale is one of the most commonly used clinical methods to assess UE strength (19–22). It is easy to use, does not require any specialized equipment, and can be done by occupational therapists, physical therapists, nurses or physicians, and other healthcare professionals. MMT is 236designed to evaluate individual muscles from the upper and lower extremities. Each muscle is tested against the resistance of the clinician and subsequently graded against the patient’s strength on a scale from 0 to 5. Scoring is subjective, based on the clinician’s perception. Proper technique must be used during testing to ensure a reliable and valid measure. Important limitations to be aware of include (a) the test is dependent on patient effort which may be poor in the presence of pain or psychological issues; (b) the patient must not be wearing restrictive clothing; (c) muscles should first be tested in a gravity-eliminated plane and modified accordingly for individuals who cannot engage the muscles against gravity; (d) the less affected side should be tested first for comparison with the more effected side; and (e) discrimination between a 0 and a 1 is done by instructing the patient to contract the muscle while the clinician places their hand gently on the muscle being tested. This grading system classifies strength levels but does not directly quantify strength.
Alternatively, quantitative tools used to evaluate and track muscle strength over time can provide a useful method for clinical management in MS. Quantitative methods of strength assessment use a strain gauge or other measuring device, typically a hand-held dynamometer or grip dynamometer, or use a fixed apparatus to measure isokinetic or isometric strength (23). Dynamometry offers a more precise measurement of the force that a muscle produces and offers the sensitivity to track changes over time that a clinician may not subjectively notice using MMT. These methods can be used to evaluate grip strength, pinch strength, as well as the strength of wrist, elbow, and shoulder musculature. Dynamometry has been found to be fast, objective, clinically accessible, and valid in MS, and there are normative values available for comparison (24–27). Proper technique is also important for reliable measurement. Dynamometry also has limitations the clinician should keep in mind: (a) equipment is necessary for measurement; (b) not all muscles can be tested (e.g., lumbricals, and other small hand muscles); and (c) not all clinicians use the same equipment, and thus there is limited availability of comparable measurements to clinicians across specialties and clinic settings.