Multiple sclerosis - The influence of time on disability:
Despite the different types of multiple sclerosis (MS), the long-term
consequences are very similar, according to a study published in the New
England Journal of Medicine. After people with MS reach a certain level of
disability, acute bouts of symptoms (relapses) have little affect on the
time course of the illness.
Dr. Christian Confavreux of the Hopital Neurologique in Lyon, France, and
colleagues studied 1,844 people with MS. Of these, 85 percent had
relapsing-remitting MS - the common form of the illness in which long
periods of disease remission (months or years) are interrupted by episodic
relapses. The remaining 15 percent had progressive MS, with symptoms that
worsen steadily without relapses.
People in the relapsing-remitting group developed permanent disability more
slowly than those with progressive MS. But once both groups had reached a
similar degree of disability - measured as the ability to walk only
approximately 1,640 feet or 500 meters - the time course of continued
neurological disability was similar for everyone regardless of whether they
had further relapses.
MS is a life-long, potentially debilitating autoimmune disease that affects
the brain and spinal cord. Inflammation of the nervous system may result in
the destruction of the insulating sheath (myelin) that covers nerve fibers,
leaving multiple areas of scarring (sclerosis). This scarring impairs nerve
conduction and affects muscle coordination, visual sensation and other nerve
signals. Its cause is unknown.
An estimated 400,000 people in the United States and 1.1 million people
worldwide have MS. Women have twice the risk of developing MS compared to
"This study demonstrates that much of the important disability that occurs
in some patients with long-standing MS occurs as a result of slow
progression of neurological damage rather than as a result of acute
flare-ups of the disease (relapses)," says John Noseworthy, M.D., a
neurologist at Mayo Clinic, Rochester, Minn. "Occasionally patients become
seriously disabled by individual attacks, but the majority of the important
disability develops more slowly over many years. This may mean that nerve
cells and nerve fibers degenerate with time."
Dr. Noseworthy adds, "It is hoped that early treatment may slow, prevent or
delay the occurrence of disability, but this has not yet been adequately
proven. Long-term studies of the FDA-approved (Food and Drug
Administration), partially effective, injectable immunomodulatory drugs -
interferon beta-1b (Betaseron), interferon beta-1a (Avonex) and glatiramer
acetate (Capaxone) are much needed."