Multiple Sclerosis: Role of Physical Therapy in Disease-Related Mobility Deficits

Despite significant improvements in diagnosis and management of multiple sclerosis (MS), many people-including some physicians-still assume that a diagnosis foreshadows an inevitable decline into progressive disability.

The idea of inevitable physical decline in MS may have its roots in the fact that MS is understood as a disease of CNS demyelination. Although correct, this view does not take into account that MS is also a disease of mobility. As the disease progresses, the patient’s ability to walk becomes increasingly impaired. Balance worsens, which leads to falls. Patients may choose to become less mobile to decrease the risk of falls; their sedentary lifestyle leads to further complications. Medication offers little to address these mobility deficits.

Physical therapy can specifically address mobility deficits associated with MS. Unfortunately, clinicians who see patients with MS rarely refer them for physical therapy (PT). This may arise from a simple lack of awareness that (as with other kinds of neurologic dysfunction) PT is indicated for MS-related mobility deficits. PT is not solely for treatment of orthopedic dysfunction.

A review of some of the most common physical disabilities seen in MS will illustrate how PT can help address these problems.

Foot drop

Foot drop is usually caused by a combination of weakness of the muscles of dorsiflexion and tightness in the muscles of plantiflexion. The weakness can be secondary to a loss of CNS activation, to disuse, or to some combination of the two. The tightness can be a result of plantiflexor spasticity, prolonged positioning in plantiflexion leading to diminished range of motion, or both.

Regardless of the cause, foot drop leads to diminished ambulation and falls, which can lead to prolonged hospitalization and convalescence. Although foot drop is common in persons with MS, it is not inevitable. A program of active and passive plantiflexor stretching, dorsiflexion strengthening, and exercises to retrain the ankle to function appropriately during gait and balance activities can be carried out by a physical therapist who has experience in treating MS neurologic dysfunction. 

The sooner the program is started, the better chances are of success. Bracing with an ankle foot orthosis can sometimes be effective but may lead to further weakness and contracture from immobilization; thus, this should only be tried if exercise programs have been ineffective.

Gait and balance dysfunction

In persons with MS, gait difficulties are common and multifactorial. Gait may be limited by foot drop, and by hip and knee weakness and stiffness, lower extremity sensory loss, visual and vestibular damage, and cognitive loss.

Neurogenic fatigue is one of the common manifestations of MS. The patient appears to walk unimpaired over short distances, but over longer distances is severely impaired. This is important to note because physicians often test gait during office examinations by watching patients walk short distances. To prevent and potentially reverse complications from gait dysfunction, physical therapists need to see patients with MS early on the disease’s course. The multifactorial nature of gait dysfunction in MS requires that a meticulous gait evaluation be done so that specific and appropriate interventions can be performed.
   
Balance loss in MS is similarly complex and is usually caused by a combination of factors that include weakness, stiffness, sensory loss, visual and vestibular loss, motor control impairments, and cognitive issues. A thorough balance evaluation will expose factors responsible for the balance loss and allow for treatment to address those factors.

Weakness and stiffness 

Common findings in MS, weakness and stiffness may be a consequence of CNS dysfunction (such as spasticity or lesions in the motor systems and tracts) or to secondary disuse (ie, when the patient knowingly or unknowingly stops using a specific limb or performing a specific action). Stiffness can cause weakness and weakness can cause stiffness. A PT evaluation can determine whether the weakness and stiffness are manifestations of CNS dysfunction, secondary disuse, or some combination thereof.

Although stretching and strengthening exercises are clearly indicated, they must be appropriately tailored to the needs of the individual patient. Stretching should be gentle and prolonged; extremes of range are to be avoided. Strengthening programs interspersed with rest periods avoid limitations from neurogenic fatigue.

Fatigue

One of the most common findings in MS, fatigue has been described as “a subjective lack of physical and/or mental energy that is perceived by the individual or caregiver to interfere with usual and desired activities.” It can be primary (due to CNS dysfunction) or secondary (caused by disuse atrophy from an overly sedentary lifestyle that the MS patient has adopted). Movement becomes increasingly difficult and exhausting, leading to a cycle of further immobility and worsening fatigue.

Attempts to increase fitness and mobility via standard exercise programs are often ineffective because the patient becomes too fatigued to exercise for more than a few minutes at a time. Exercising intermittently-ie, exercise interspersed with rest breaks-allows for a much larger volume of work to be performed before fatigue can accumulate and makes possible greater fitness gains.

Summary
• A diagnosis of MS does not necessarily mean that the person will experience severe disability. With proper medical and PT management, MS should be viewed as a disease that can be managed over a lifetime.
• MS is a disease of mobility. PT is indicated for treatment of the mobility deficits; referral should come as early as possible in the course of the disease, before deficits can become profoundly disabling.
• The mobility deficits that are seen in MS are multifactorial. Loss of strength, range of motion, endurance, and gait and balance occur as a result of a complex assortment of interacting reasons. Physical therapists are uniquely trained to evaluate, assess, and treat the mobility deficits that occur in MS.



For more information:

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• Krupp L, Alvarez L, LaRocca N, Scheinberg L. Fatigue in multiple sclerosis. Arch Neurol. 1988;45:435-437.
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• Multiple Sclerosis Council for Clinical Practice Guidelines. Fatigue and multiple sclerosis: evidence-based management strategies for fatigue and multiple sclerosis (Clinical Practice Guidelines). Washington, DC: Paralyzed Veterans of America. 1998. http://www.mscare.org/cmsc/images/pdf/fatigue.pdf
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