The area where the myelin disappears also hardens into scar tissue; 'multiple sclerosis' literally means 'many scars.' Patients experience a wide range of symptoms, including blurred vision, slurred speech, fatigue, muscle spasticity, loss of balance and tingling, numbness or burning sensations.
No one is sure exactly what causes MS, but researchers have some increasingly developed theories. Experts know the myelin loss occurs when the body's immune system attacks its own cells. The latest research suggests this autoimmune disorder is triggered by a virus, perhaps one like measles or herpes that is common in humans. Inheritance plays a partial role, making some people more susceptible to MS.
The disease strikes most typically in middle age, and two-thirds of patients are women. "There are approximately 350,000 to 500,000 patients in the United States," said Dr. Clifford Roer of the Multiple Sclerosis Foundation, one of the three nationwide advocacy groups. The International Federation of Multiple Sclerosis Societies estimates that there are about 2.5 million MS sufferers worldwide.
Contrary to the public perception of MS as a slowly progressing degenerative disease, nearly half of MS patients only experience isolated flare-ups of the disease. Twenty-five percent of MS sufferers - Montel Williams is one - have relapsing-remitting MS (RRMS), which is marked by days, weeks or months of severe symptoms followed by periods of relative calm. Another 20 percent have benign MS, which is marked by a small number of attacks followed by complete remission.
The remaining MS have either Primary or Secondary Progressive MS, which means the disease slowly gets worse. Primary patients have no attacks but a gradual worsening of symptoms; secondary patients have their periodic attacks grow more severe over time.
New drugs have provided fresh hope in recent years that MS can be slowed or even stopped altogether. Scientists' growing understanding of the disease has spurred optimism in the MS community.
"There are more than 81 clinical trials on symptom management and remyelination under way," said Roer. "These certainly produce a lot of hope."
Leading the charge is a new class of drugs known as interferon-betas. Although they are only approved thus far for people with RRMS, they have made marked improvements in quality of life for these patients.
Roer said that because the interferon-betas can carry serious side effects such as flu-like symptoms and skin cell necrosis, the Multiple Sclerosis Foundation has been backing research in alternative treatments.
"Acupuncture and massage therapy have been very helpful for pain, spasticity and bladder and bowl problems," he said, "so patients don't have to take so many pharmaceuticals."
"MS is a manageable disease, and not life-threatening," Roer concluded.
"Seventy-five percent of all MS people do not end up in a wheel chair.
It is a serious disease, but it is something that can be managed."