Multiple sclerosis is a chronic disease

Introduction
Definition of multiple sclerosis
Multiple sclerosis is a chronic disease of the central nervous system including the brain, spinal cord, and optic nerves. The central nervous system is made up of nerve cells that send signals to each other. Each nerve cell is covered with a protective lining called myelin which acts like insulation on an electrical wire. It allows signals to pass between nerve cells at high speed. In multiple sclerosis, disease activity damages the myelin in a process called "demyelination" (What is multiple, n.d.). This leads to an eventual breakdown in the signal leading to symptoms of the disease. The demyelination process interferes with nerve impulse transmission, affects muscular control, and causes of variety of sensory, motor, and psychological symptoms. Because multiple sclerosis can attack any area of the central nervous system, the signs and symptoms are many and varied. Not all people with MS have the same symptoms. They vary from person to person, and the symptoms a person experience depends on where the disease activity is focused. They are associated with what the nerves in the affected area are responsible for controlling. Sensory symptoms may include numbness, tingling, pain, burning, itching, facial pain, and visual disturbances. Motor symptoms may include speech impediments, weakness, tremor, difficulty walking, lack of coordination, and bowel or bladder problems. Problems with memory, attention, and problem solving are common symptoms of MS. Multiple sclerosis symptoms generally appear between the ages of twenty and forty. While the etiology of MS is not understood, researchers are studying the immunologic and genetic factors in trying to understand what causes MS. (About MS, n.d.). This is an important step toward finding effective ways to treat it and ultimately cure or prevent the disease all together. The impact of a person being diagnosed with multiple sclerosis can be overwhelming and