EMG ACTIVATION DIFFERS BETWEEN ADULTS WITH AND WITHOUT MULTIPLE SCLEROSIS AT THE ANKLE

Multiple sclerosis (MS) is an autoimmune disease that majorly affects the brain and the spinalcord. The disease affects the central nervous system (CNS) and thus causes limitations ofindividuals to carry out various activities. In MS, the myelin sheath that covers nerve cell axonis destroyed causing inflammation. Destruction of the membrane leads to slowed conveyanceof signals from the spinal cord to the brain, which as a result leads to reduced response todifferent stimuli. Inflammation of the nerve occurs mostly when the immune cells from thebody attack the nervous system. The inflammation is not only limited to the spinal cord, butsometimes extends to optic nerve or the brain.The purpose of this study was to quantify the steady-state isometric muscular control ofthe ankle plantar flexors in individuals with MS. We hypothesized that individuals withMS will have a higher coefficient of variation (CV) during a low level isometriccontraction compared with healthy controls. Secondarily, we hypothesized that the surfaceEMG (sEMG) of the gastrocnemius in individuals with MS would exhibit alteredharmonics when attempting to sustain the isometric contraction.