Multiple sclerosis (MS) is a nerve disorder caused by the destruction of the insulating layer, myelin, surrounding nerve fibres in the central nervous system (brain and spinal cord). The insulation helps electrical signals pass quickly and smoothly between the brain and the rest of the body. When the myelin is destroyed, nerve messages are sent more slowly and less efficiently. Nerve communication is disrupted and is made worse when scar tissue (plaques) form over the damaged areas. MS symptoms occur when the brain and spinal cord nerves no longer communicate properly with other parts of the body: movement, sensation, and bodily functions are all affected. However, the severity of MS, despite being chronic, differs between individuals.