Myotonic Dystrophy Foundation

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Physical Therapy Management

Exercise

Individuals with myotonic dystrophy often have questions about exercise. Exercise, including range of motion, strengthening and cardiovascular (aerobic) exercise, is important for the management of the musculoskeletal and cardiorespiratory manifestations of myotonic dystrophy. Range of motion exercises are important in maintaining joint function and muscular balance and, may play a role in reducing pain that is caused by muscular imbalance or tightness. As muscles atrophy resulting in weakness, gravitational pull may limit a person’s ability to move a body part through its entire range of motion and therefore it may be important to change the position of the body part to minimize the pull of gravity. For example, people may have difficulty raising their arms up in sitting or standing position, i.e. performing shoulder abduction in an antigravity position, but may have the ability to perform this movement when lying down in a supine position where gravity is eliminated. Individuals may also participate in range of motion exercises that are more dynamic in nature. This includes yoga and pilates based activity that can either be done individually or in a class setting. Education regarding range of motion exercise is essential to the management of the symptoms related to the musculoskeletal system.

We know that weakness occurs as part of the disease process; however, additional strength may be lost secondary to disuse. Strengthening exercises may help to minimize the disuse weakness; but there is also a concern that too much exercise or inappropriate exercise may hasten disease progression, and hence finding the right balance for each individual is important. The evidence available regarding the role of exercise in myotonic dystrophy is limited. In a Cochrane review published in 200519, the authors examined the safety and efficacy of strength and aerobic training in neuromuscular diseases. They identified a total of 36 studies; however, there were only two randomized controlled trials that fulfilled their inclusion criteria. Based on these studies the authors concluded that strengthening exercises at a moderate intensity did not worsen the disease progression in persons with myotonic dystrophy.19, 20 Many of the studies involving individuals with myotonic dystrophy were excluded from the review because they lacked randomization.21-24, 25, 26Many of these studies also grouped different neuromuscular diseases together, making it difficult to draw conclusions about the individual’s response to exercise in a specific disease like DM.. Disorders like DM are difficult to study as they are rare diseases and it is difficult to enroll enough patients to carry out a well powered randomized control trial. Other problems cited with the reviewed studies included lack of detailed descriptions of the exact exercise protocols used and short durations of the exercise trials. Cup et al27chose to look at the evidence related to exercise in individuals with neuromuscular diseases with expanded criteria than those in the Cochrane reviews. Based on their analysis of the studies they concluded that the evidence suggests that strengthening exercises in combination with aerobic exercises are “likely to be effective”. Given the evidence from the 2 major reviews that exercise may be effective and that moderate exercise does not worsen disease progression, some general recommendations can be made to guide clinicians and individuals with myotonic dystrophy.

Depending on the activity level of the individuals, they may benefit from a strengthening program. Individuals who lead an active lifestyle may not have much disuse weakness, and further activity may be fatiguing to them. However, others who lead a more sedentary lifestyle may benefit from a strengthening program. Strengthening exercise can be accomplished in several ways with resistance provided by gravity, water – in a pool - or equipment such as elastic bands, free weights and machines. As mentioned before, Yoga and Pilates types of exercises may also be recommended as part of a strengthening program, but there are no specific studies that have examined the effects of these programs. It is essential that individuals with myotonic dystrophy work with providers knowledgeable about their condition have proper baseline evaluation and appropriate follow-up to monitor and modify the program as necessary.

Cardiovascular exercise has been found to be safe in people with myotonic dystrophy. In a study published after the Conchrane review, the authors concluded that performing aerobic activity at a low intensity can improve cardiovascular fitness as well as increase self reported strength and performance of activities of daily living.28 Cup et al.27 also concluded that there was “indication of effectiveness” for aerobic exercises in individuals with muscle disorders. However, because of the cardiac involvement that can occur in persons with myotonic dystrophy, it is essential that individuals have a physical, appropriate cardiac evaluations and clearance from their primary care physicians prior to initiating an aerobic exercise program.

Pain

A wide variety of methods have been used in the treatment of pain in individuals with myotonic dystrophy. The use of non-steroidal anti-inflammatory medications or acetaminophen, exercise (strengthening and ROM), and heat are the most common therapies used to manage pain. 16 Individuals should consult their physician for recommendations regarding the use of medication for pain relief.

Orthotics

Lower extremity weakness can affect a person’s ability to walk safely, especially on uneven surfaces initially. Ankle dorsiflexion weakness often leads to a foot drop and decreased foot clearance during the swing phase of gait. Some individuals may compensate for the ankle dorsiflexion weakness by using a steppage gait pattern, i.e. lifting their knees higher to help the foot clear the ground. The use of ankle-foot-orthotics can help to correct the foot drop; however, care must be taken in prescribing an AFO. Several factors may play a role in the effectiveness of orthotic use in the lower extremities. The additional weight that may be added to the lower extremity by a brace can significantly alter the person’s ability to ambulate, and hence it is important that the orthotics are made out of the lightest materials available. It is also important to consider the person’s ability to don and doff the orthotic devices, especially in the presence of hand weakness and decreased hand function. Orthotic fit is often difficult because people with myotonic dystrophy have muscular wasting, and bony landmarks often become more prominent and susceptible to skin irritation and breakdown. Comfort and satisfaction are important in promoting the use of the prescribed device. Compliance suffers if the prescribed orthotic device is uncomfortable or too difficult for the client to get on and off independently. Furthermore, there has been very limited research on the effect of orthotic use on energy expenditure during walking and is definitely an area that needs further investigation to prescribe appropriate orthotics to this patient population.29 In cases where the neck muscles are also affected, neck braces may also be beneficial. Many of these braces are off the shelf and can be fit by an orthotist.

Assistive Devices/Adaptive Equipment

Individuals with myotonic dystrophy are at a higher risk for falls. Decreased visual acuity, lower extremity weakness and depression can play a role in increasing the risk for stumbles and falls .30 The use of canes, walkers, wheelchairs, and powered mobility devices can be used to allow a person to continue to be safe and independent in mobility. Adaptive equipment, such as long handled sponges, foam buildups on silverware and pens, and button hooks can make performing bathing and dressing easier and allow individuals to be more independent in caring for themselves. When assessing for adaptive equipment, a referral to an occupational therapist may also be beneficial.

Children with Myotonic Dystrophy

Even though DM is considered the most common of the adult muscular dystrophies, as has been mentioned before, congenital (present at birth) and childhood presentations are recognized. Congenital myotonic dystrophy tends to be more severe than the childhood form and is often associated with hypotonia, respiratory insufficiency and feeding problems present shortly after birth.3, 31 When symptoms arise during the childhood years, the progression is similar to that in adult onset myotonic dystrophy, however since the symptoms start earlier, they, may be more severe later in life.2 Cognitive impairment is also present in these phenotypes of myotonic dystrophy, with the involvement being more severe in the congenital form.32, 33The need for physical therapy services can be highly variable and individualized based on the type and severity of the symptoms. The areas addressed by physical therapists will be the same as in the adult population, including recommendations regarding exercise, orthotics, and adaptive equipment. Additionally, the child will be developing motor skills, and there may be a need for short episodes of intensive hands on therapy to facilitate motor development and attainment of motor milestones. Hands on physical therapy services can be provided several different ways ranging from traditional home or clinic based activities, to aquatic therapy to the utilization of equine movement called, hippotherapy. Traditional home or clinic based services utilize the child’s natural environment, including daycare, preschool, or playground to address specific developmental or functional needs.

Aquatic therapy uses the physical properties of water to perform exercise. The buoyancy provides support and facilitates antigravity movements. The viscosity or resistive properties of the water allow for strengthening of the postural and limb muscles. These qualities of the aquatic environment have been shown to be beneficial in improving functional mobility of children with mobility limitations.34, 35Hippotherapy is a treatment strategy in which the movement of a horse is used as a treatment strategy to address impairments and functional limitations in people with neuromuscular dysfunction. Hippotherapy has been shown to improve upright posture, and balance therefore positively impacting gross motor function and walking ability in children with developmental delay.36, 37

There have not been any studies that look specifically at using the above interventions with children with myotonic dystrophy, although developmental delay is a commonality. It is also difficult to document the specific impact that these interventions have versus the natural gain that occurs with development since there are very few appropriately controlled longitudinal studies reported in the literature. Further research is needed to determine appropriate type, frequency, intensity, and duration of physical therapy services in children with myotonic dystrophy.

Currently, the frequency and intensity of the hands on services vary depending on the individual child’s needs. These may be followed by more limited episodes where the physical therapist will play a more consultative role, monitoring the child’s development and working with the family to set up a home based program of daily activities and exercises to maximize the child’s functional abilities. Within the school system, the physical therapist will work with the school team – classroom teachers, gym teachers, school nurse, and counselors etc educating them regarding the condition and the appropriate activities and supports within the school environment to assure safety, mobility and maximize the learning opportunities.

In this section we have attempted to meet the needs of therapists who may encounter patients with DM rarely and hence may not have much knowledge of the condition. We hope that the information and the references we have provided will help them get started in meeting the needs of their patients. For individuals with myotonic dystrophy who may be reading this section – we hope we have given you enough information about the role of physical therapists in your care, so that you are better prepared to partner with them in meeting your needs. We would appreciate any feedback from all readers about how we might make this section more responsive to their needs.