As a result, nerve impulses which are the communications from the brain to the muscles and other parts of the body are impaired. The disease may also cause brain atrophy. The nerve damage can manifest with physical symptoms or sensory disturbances, such as weakness, tremors, muscle stiffness, balance problems, loss of coordination, numbness, blurry vision or a sudden and temporary loss of vision.
Cognitive impairment can also occur, especially in later stages of the illness.
Multiple sclerosis tends to appear first before the age of 40. Women appear more prone than men to develop it. It is also much more common in northern, temperate climates than in tropical areas. The cause of MS has yet to be clarified. It appears to be an auto-immune condition.