Wikipedia:Today's featured article/November 18, 2005
Multiple sclerosis is a chronic disease that affects the brain and spinal cord. MS can cause a variety of symptoms, including changes in sensation, visual problems, weakness, depression, and difficulties with coordination and speech. Although many patients lead full and rewarding lives, MS can cause impaired mobility and disability in the more severe cases. MS affects neurons, the cells of the brain and spinal cord that carry information, create thought and perception, and allow the brain to control the body. Surrounding and protecting these neurons is a layer of fat, called myelin, which helps neurons carry electrical signals. MS causes gradual destruction of myelin (demyelination) in patches throughout the brain and/or spinal cord, causing various symptoms depending upon which signals are interrupted. The name multiple sclerosis refers to the multiple scars (or scleroses) on the myelin sheaths. MS results from attacks by an individual's immune system on his or her own nervous system, and it is therefore categorized as an autoimmune disease.