Multiple sclerosis is a chronic, unpredictable disease of the central nervous system (the brain, optic nerves, and spinal cord). It is thought to be an autoimmune disorder. This means the immune system incorrectly attacks the person's healthy tissue. MS can cause blurred vision, loss of balance, poor coordination, slurred speech, tremors, numbness, extreme fatigue, problems with memory and concentration, paralysis, and blindness and more. These problems may be permanent or may come and go. Most people are diagnosed between the ages of 20 and 50, although individuals as young as 2 and as old as 75 have developed it. MS is not considered a fatal disease as the vast majority of people with it live a normal life-span. But they may struggle to live as productively as they desire, often facing increasing limitations.

Anyone may develop MS but there are some patterns. More than twice as many women as men have MS. Studies suggest that genetic factors make certain individuals more susceptible than others, but there is no evidence that MS is directly inherited. It occurs more commonly among people with northern European ancestry. People of African, Asian, and Hispanic backgrounds are also diagnosed with MS, however, the incidence is much lower.

Approximately 18,000 Australians have MS, and it is estimated that every year the number of people diagnosed increases by 7%. World-wide, MS affects about 2.5 million people. Because of the difficulty in diagnosing the disease, and because symptoms can be completely invisible, these numbers can only be estimated.

Symptoms of MS are unpredictable, vary from person to person, and from time to time in the same person. For example: One person may experience abnormal fatigue and episodes of numbness and tingling. Another could have loss of balance and muscle coordination making walking difficult. Still another could have slurred speech, tremors, stiffness, and bladder problems. Sometimes major symptoms disappear completely, and the person regains lost functions. In severe MS, people have symptoms on a permanent basis including partial or complete paralysis, and difficulties with vision, cognition, speech, and elimination. Read more about symptoms here.

MS symptoms result when an immune-system attack affects myelin, the protective insulation surrounding nerve fibers of the central nervous system (the brain and spinal cord). Myelin is destroyed and replaced by scars of hardened "sclerotic" tissue. Some underlying nerve fibers are permanently severed. The damage appears in multiple places within the central nervous system. Myelin is often compared to insulating material around an electrical wire; loss of myelin interferes with the transmission of nerve signals.

In rare cases MS is so malignantly progressive it is terminal, but most people with MS have a normal or near-normal life expectancy. Severe MS can shorten life.

No. Moreover, the majority of people with MS do not become severely disabled. Two-thirds of people who have MS remain able to walk, though many will need an aid, such as a cane or crutches, and some will use a scooter or wheelchair because of fatigue, weakness, balance problems, or to assist with conserving energy.

No. MS is not contagious and is not directly inherited. Studies do indicate that genetic factors may make certain individuals susceptible to the disease.

Not yet. There are now FDA-approved medications that have been shown to "modify" or slow down the underlying course of MS. In addition, many therapeutic and technological advances are helping people manage symptoms. Advances in treating and understanding MS are made every year, and progress in research to find a cure is very encouraging.

In early MS, symptoms that might indicate any number of possible disorders come and go. Some people have symptoms that are very difficult for physicians to interpret, and these people must "wait and see." While no single laboratory test is yet available to prove or rule out MS, magnetic resonance imaging (MRI) is a great help in reaching a definitive diagnosis.