2.1
Multiple sclerosis is a disease of the central nervous system, which usually starts in early adult life. It is characterised by neurological symptoms caused by episodes of inflammation and scarring in the white matter of the brain or spinal cord. It causes a range of symptoms including problems with vision, arm or leg movement, sensation or balance. Muscle spasms, pain, fatigue, and emotional problems or depression may also occur. Symptoms may vary over time and some people become profoundly disabled. The 3 most common types of multiple sclerosis are: relapsing–remitting, in which periods of good health or remission are followed by sudden onset of symptoms or relapses; secondary progressive, in which symptoms gradually worsen with fewer remissions; and primary progressive, which involves a gradual, continuous worsening of symptoms.