Multiple Sclerosis (MS) is a chronic inflammatory disease of the central nervous system. MS affects approximately 3.0 million people globally, with about 300,000 cases in the United States. Twice as many women as men have MS. The average ages for onset of MS is 20-40 years. In MS, cells in the immune system attack and destroy myelin, the fatty tissue surrounding nerve cells (http://www.phylomed.com/MS.html). Scar tissue replaces the myelin, interfering with the transmission of nerve signals and leading to numbness, fatigue, spasticity, loss of muscle control, and various other debilitating symptoms. There are four broad theories concerning the etiology of MS. The immune system, environment, viral infections, and genetics are possible factors attributed to the cause of MS.
Spasticity refers to an increase in muscle tone that causes muscle stiffness or spasms (Sibley, 105). There are two types of spasticity prevalent in people with MS: phasic spasms and a sustained increase in muscle tone. Phasic spasms sub-categorize into two types of spasticity: flexor and extensor. In flexor spasticity, the hips and knees of the person bend forward, due to tightening of the hamstrings. In extensor spasticity, the legs of the patient cross over at the ankles or lock together, with the hips and knees remaining rigid (http://www.nmss.org/msinfo/cmsi/spasticity.html). Spasms also occur less frequently in the arms, backs, and necks of people with MS. Both types of spasticity debilitate patients and lead to difficulties in performing daily tasks. Phasic spasms disrupt the balance of the patient and can cause severe pain.