Reprinted from Motor Disorders, edited by David S. Younger, MD, Chapter 38.

Once the diagnosis of a progressive neuromuscular disease is made, there is a tendency to inform the patient or family that there is no effective intervention. This is done despite the availability of physical medicine interventions that can in many instances prolong life without hospitalization or tracheostomy and, in virtually all instances, temporarily restore considerable function to the patient. The worst case scenario is advanced amyotrophic lateral sclerosis (ALS), in which 88 (1) to 97% (2) of lives are prolonged and function maximized by physical medicine interventions. In 1991, the Honorable Justice Sam Filer, stricken with advanced ALS and essentially no functional movement other than that of his eyelids for over 3 years, communicated the following by computer-driven voice synthesizer:

The judge is not at all unique. Other 24-hour ventila-tor users with advanced ALS or other severe neuromuscular conditions continue gainful employment and have a positive attitude about their lives (2). Optimism can be encouraged in similarly affected patients by making aspects of neuromuscular rehabilitation available in a multidisciplinary care program to optimize the patient's options.

DEFINITIONS

A disease is a pathologic condition with a set of symptoms and signs. An impairment results from the loss or abnormality of psychologic, physical, or anatomic structures or function or disease therein (4). When an impairment prohibits the accomplishment of a task required for personal independence or physical well-being, then a disability is created. The World Health Organization defines disability as any restriction or lack resulting from an impairment of ability to perform an activity in the manner or within the range considered normal for a human being (4). For example, impairment of either respiratory muscle function, airway obstruction, or anatomic destruction of the lungs can lead to a disabled cough mechanism. To assess the status of the general abilities of patients, rehabilitation specialists evaluate activities that are normally performed on a daily basis to maintain personal independence, such as the ability to breathe, eat, bathe, groom, toilet, move about, and communicate, all of which have an impact on our capacity to live independently. When deficiencies are evident, then it is necessary to assist or substitute the abnormal body function with physical medicine aids.

According to the World Health Organization, a handicap is the disadvantage of a given individual that results from an impairment or a disability that limits or prevents the fulfillment of a role that is normal for that individual (4). Some patients with acquired immunodeficiency syndrome may be handicapped socially without being physically disabled. A child receiving full ventilatory support by an indwelling tracheostomy tube may be banned from attending school or even from returning home because, according to state regulations, the presence of an "open wound" necessitates continual family or nursing attention. The same patient using physical medicine aids for noninvasive ventilatory support might be permitted to return to the community (5,6).

Patients with neuromuscular impairments, can have resulting disability may be due to breathing dysfunction, skeletal muscle dysfunction, musculotendinous contractures, primary skeletal or cardiopulmonary pathology, poor endurance, other associated disease pathology, or some combination of impairments. The patient can be further handicapped by architectural barriers, public policies, inadequate finances, family support, or education. Clinicians should identify and differentiate the disease process, impairments, disabilities, and handicaps faced by the patient so that physical medicine interventions and psychosocial support can be instituted and the person returned to the fullest possible physical, mental, social, and economic independence. Physical medicine interventions pertain to the use of equipment or activities that may include noninvasive methods of ventilatory support and cough facilitation, exercises, range-of-motion, and surgical interventions based on pathokinesiologic principles to maximize breathing, coughing, nutrition, and physical functioning.

MANAGEMENT STAGES

It is useful to consider the example of the three clinical stages of Duchenne muscular dystrophy (DMD) (Table 1). The clinician who understands the management principlesfor DMD can apply them to patients with other neuro-muscular conditions.

Ambulatory Stage

In this stage, the diagnosis of DMD is established and the patient and family are told about possible treatment interventions, and the major options in each subsequent management stage are discussed. This is particularly important for optimizing compliance for later surgical therapies to maintain leg function, prevent scoliosis, avoid later hospitalizations for pulmonary morbidity and tracheostomy, and to prolong survival without invasive measures. Psychological support is important to prevent feelings of guilt or sympathy from disrupted family psychodynamics, alienated family members, and to avert overprotection to the point of delaying the patient's emotional maturity and the assumption of self directed activities and decision making.

Musculotendinous Contracture Management

The pathokinesiology of progressive gait difficulty has been described for DMD (7,8), but it applies equally well to other myopathies, childhood polymyositis, and spinal muscular atrophy (SMA). Asymmetric hip extensor weakness leads to anterior and lateral pelvic tilt, asymmetric hip flexor contractures, and accentuated lumbar lordosis. Tensor fascia lata and iliotibial band contractures lead to a wide-based gait with internal rotation and flexion at the knees. With increasing quadriceps weakness, the patient stabilizes the knee by keeping the weight line anterior to the knee, but it must also be kept behind the hips because of weak hip extensors. Intact plantar flexors encourage toe walking and lead to equinus deformity that initially stabilizes the knees. Iliotibial tract tightness increases the torque on the femur and flexes the knee until the center of gravity shifts from behind the hip to the front of the knees. Strong foot evertor and tibialis posterior muscles destabilize the subtalar joint and lead to falls on uneven surfaces and later on level surfaces. Unless aggressively treated, the average age of wheelchair dependence in DMD is 8.6 to 9.5 years (range, 6 to 15 years) (9-12).

Although leg weakness plays a major role in the eventual loss of walking, musculotendinous contractures destabilize the gait prematurely as seen by its prevention or early correction with bracing until walking ceases (13). An early prophylactic approach to preventing contractures depends on careful monitoring of the patient's muscle strength, articular range-of-motion, and ability to walk and rise from the floor (14). Surgically lengthening the Achilles tendon and hamstrings resection of the ili-otibial bands, lengthening of hip flexor muscles, and transferring the tibialis posterior tendon to the dorsum of the foot to improve ankle dorsiflexors equalize strength in each joint. These are generally performed between ages 4 and 7. (Fig. 1) (14). These procedures are safer and better tolerated when performed early in the disease and require less postoperative physical therapy and stabilization gait. They also break the vicious cycle of weakness that leads to imbalance and contractures. Early surgical rehabilitation also reverses and prevents leg contractures during the ambulatory stage without long-term physical therapy, burdensome splinting, or bracing (13,14). Similar principles have been applied to patients with milder myopathies, but those with better proximal strength require only certain elements of the surgical intervention such as tendo-Achilles lengthening or tibialis posterior tendon transfer. Other approaches to the management of leg contractures include daily muscle stretching with or without concomitant bracing, stretching, and physical therapy (13,14). By comparison, in the 1950s, Paul (15) found a third of patients with DMD stopped walking before age 6 years. When contractures are prevented by early surgery and a short course of postoperative physical therapy, ongoing physical therapy and splinting are unnecessary.

The nighttime use of plaster casting in combination with physical therapy is another approach; however, they should be redone every 6 months, are extremely uncomfortable and therefore poorly tolerated, and effective programs place considerable long-term burden on patients and their families. It has been suggested that this approach maintains ambulation to age 10.3 years (16,17).

Early conservative management, then musculotendinous releases, resection of iliotibial bands, and long-leg bracing when the patient is approaching wheelchair dependence prolongs ambulation or at least the ability to stand (18,19), but this late intervention is less well tolerated and requires intensive postoperative physical therapy and the use of cumbersome, expensive, and often poorly tolerated long-leg braces.

Simple ankle-foot orthoses are not indicated for assisted ambulation in patients with neuromuscular disease unless the muscle weakness is limited to the ankles and knees. They can sometimes be used along with Lof-strand crutches after late surgical contracture releases. They slow the speed of walking and make rising from a chair or going up steps more difficult because of reduced knee flexion and ankle extension. In patients with Charcot-Marie-Tooth neuropathy and other conditions with primarily distal involvement, polypropylene ankle-foot orthoses relieve toe dragging and support pes cavus supinated feet. A plastic or metal ankle-foot orthosis with an adjustable locked ankle also provides knee and ankle control by improving tibial stability in these cases.

Maintaining Pulmonary Compliance

Just as frequent passive range-of motion is necessary to maintain the integrity and mobility of peripheral extremity articulations, deep insufflations are important in patients with diminished vital capacity (VC) to maintain pulmonary compliance and adequate volumes for an effective cough (20). There are no published guidelines in the use of daily deep insufflations, but they are useful in patients with a VC of 50% or less of predicted normal, especially those in the stage of wheelchair dependence.

Exercise

Increased functional demands can be damaging to immature muscles, and dystrophic muscles are likewise more susceptible to overuse atrophy (21). Greater weakness was found in the preferred upper (22) and lower (23) extremities of dystrophic individuals than in the opposite nonpreferred limbs. Serum creatine kinase levels increase more so after exercise in dystrophicpatients than in normal subjects. In patients with advanced weakness, even routine activities can cause overuse atrophy.

deLateur and Giaconi (24) found that strengthening and endurance training improved strength and slowed progression of weakness early in the course of DMD(24). Vignos and Watkins (25) noted a 50% increase in strength over 4 months, with gains usually maintained for a year after resistance exercise training of antigravity muscles. Milner-Brown and Miller (26) reported similarly increased strength and work tolerance and decreased fatigue in 20- to 53 year-old patients with facioscapulo humeral, myotonic, Becker, and limb-girdle muscular dystrophies; SMA; and assorted polyneuropathies. However, the initial strength had to be greater than 15 to 20% of normal. Fowler (27) suggested that dynamic high-resistance exercise training was potentially beneficial and resulted in gains in strength if the degree of weakness was not severe or if the rate of clinical progression and the intensity of the exercise program was relatively slow. However, the period of daily exercise was limited and took into account the individual's daily physical activity level. Unfortunately, exercise programs do not benefit the patients that need help the most. There is little evidence that they result in prolonged functional abilities. Fowler and Goodgold (28) recommended starting an exercise program early in the course of the disease, restricted to individuals with slowly progressive disorders, and the use of only submaximal resistance or high-repetition aerobic exercise. Similarly, Vignos and Watkins (25) recommended 2 to 3 hours of standing, walking, or swimming per day, as long as the patient felt rested after a night's sleep. All patients should be encouraged to stay active with activities they enjoy while avoiding muscle strain.

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FIG. 1. Boy with Duchenne muscular dystrophy unable to stand without assistance before (above) and able to walk without assistance or bracing after (below) extensive release of lower extremity contractures and transfer of tibialis posterior muscles. (Photo courtesy of Dr. Yves Rideau.)