Multiple sclerosis. Computer artwork showing plaques (white) in the cerebellum, caused by multiple sclerosis (MS). MS is a progressive autoimmune disease that causes the destruction of the myelin sheath that insulates nerve cells. Depending on the areas of the brain and spinal column affected MS can have a number of different symptoms, including muscle weakness, slurred speech, depression and visual problems. There are often periods of remission, which may last weeks or even several years. There is no cure for MS but progression of the disease can be delayed and symptoms can be treated.