This is Steve Ember.
And this is Sarah Long with Science in the News, a VOA Special English program about recent developments in Science. Today, we tell about the disease multiple sclerosis.
Multiple sclerosis is not very easy to say. Those who suffer from the disease may also have difficulty naming it. One of the chief signs of multiple sclerosis is losing the ability to speak clearly. It is estimated that more than one-million people around the world suffer from multiple sclerosis, which also is called M-S.
M-S is a disease of the brain and spinal cord. The cause of the disease is not known. In patients with the disease, the covering of the nerves is destroyed. This temporarily blocks signals that pass through the nerves to the muscles of the body and back to the brain. M-S especially affects the ability to see, the sense of touch and the use of the arms and legs. Most forms of the disease are described as progressive. This means that the disease gets worse as time passes.
The central nervous system of the body includes the brain and the spinal cord. The system contains millions of nerve cells joined together by long thin fibers, like wires. Electric signals start in nerve cells and travel along these fibers to and from the brain. A fatty substance called myelin covers and protects the fibers. Myelin works in the same way that protective coverings work on electric wires.
In patients with M-S, the myelin becomes infected. It swells, or grows larger, and loses its connection with the nerve fibers. As time passes, the unconnected myelin is destroyed. Hardened tissue called scar tissue then forms over the nerve fibers. The process of hardening is called sclerosis. The word is from Latin and means scar. The many areas of hardened or scar tissue give the disease its name.
In people with M-S, when nerve signals reach a damaged area, some of the signals are blocked or delayed from traveling to or from the brain. This results in problems in different places throughout the body. These problems may appear and then disappear, sometimes resulting in long periods when there are no problems at all. Or, they may happen more and more often and become worse. Doctors do not know what causes this process.
Health experts say the disease affects women two times as often as men. And the experts say the average age of people found to have the disease is between twenty and forty years old.
For many years, doctors believed that the cause of multiple sclerosis was environmental. They believed this because a majority of those suffering from the disease lived in northern Europe and the northern half of the United States. In recent years, however, they have changed their beliefs about the causes of M-S.
Studies support the theory that there are several causes of multiple sclerosis, instead of a single gene problem or one environmental cause. The studies appear to show that genetic problems are involved in making people likely to get the disease. The studies also appear to show that environmental causes such as viruses or bacteria also may be involved. However, researchers have not identified just what those causes might be. Another likely cause is a problem within the body’s defense system, when the defense system misunderstands signals and attacks the body.
Multiple sclerosis is different from many other diseases. The signs or symptoms of the disease are not always the same. Sometimes symptoms of M-S appear and then disappear for a long time. For example, one of the symptoms is a lack of feeling in one part of the body or another.
Two other symptoms of the disease are muscle weakness or tiredness. However, these signs also could be caused by other health problems that are not M-S. Other signs include a loss of the ability to move normally, or a loss of balance. A person suffering from M-S also may have difficulty seeing well or speaking clearly.
Doctors who suspect a patient has M-S must carry out a number of tests and study the patient’s history of health problems. Signs of M-S can depend on where the nerve scars are in the body’s central nervous system. And some of these signs are not always easy to see.
Magnetic Resonance Imaging is one way to tell if a patient has multiple sclerosis. The test, also known as M-R-I, involves studying the magnetic signals from all the cells in the body. An M-R-I can show if there are scars from M-S along a patient’s nerves. A doctor can use this test to tell if a patient might have the disease, as well as by studying the patient’s medical history.
There are five main kinds of multiple sclerosis. The first kind is called Benign. This is the form of M-S that is not progressive. In ten to fifteen percent of M-S patients, the symptoms are moderate and not severe. The problems do not grow worse. They do not lead to a person becoming permanently disabled.
The second kind of M-S is called Relapsing-Remitting. About eighty-five percent of M-S patients begin with this form of the disease. More than half of M-S patients have this form at any one time. These patients have one or two major M-S-related problems every one to three years. Then they have periods with no signs of the disease. The symptoms appear suddenly and last a few weeks or months before slowly disappearing. However, the signs of the disease may become worse each time they appear.
The third kind of M-S is called Primary Progressive. In this form of M-S, the signs of the disease appear and begin to grow worse, with no periods of disappearance. About ten to fifteen percent of patients begin their struggle with M-S this way.
The fourth kind of M-S is called Secondary Progressive. This form of the disease affects
about fifty percent of those with the Relapse-Remitting form of M-S. It begins to affect them several years after they have had Relapse-Remitting M-S. When the disease changes to Secondary Progressive, the disease begins to grow worse and worse.
The fifth kind of M-S is called Progressive Relapsing. It is the worst form of multiple sclerosis. New signs of M-S can appear while existing ones grow worse. This form of the disease is rare. It affects only five percent of M-S cases.
Scientists say multiple sclerosis does not appear to be passed from parents to children. However, it does appear to be found in families. As many as twenty percent of people with M-S have at least one affected family member. And, people whose close family members have the disease have as much as a forty percent chance of also developing M-S.
It does not appear that one gene is responsible for M-S. Instead, several genes may increase the possibility that a person will develop M-S.
Common viruses or bacteria may also increase the chances that some people will develop the disease.
As with many diseases, early discovery and treatment can make a major difference in a person’s life.
M-S does not always result in severe disability. Many people are able to live normal lives. There is no cure for multiple sclerosis. However, there are new treatments for M-S that ease the symptoms of the disease. Some new treatments also can slow the progression of the disease.Several kinds of drugs are used to treat M-S. Some drugs reduce the swelling in nerve tissue.
Drugs known as beta interferons also are used to treat M-S. Interferons are genetically engineered copies of proteins found naturally in the body. These proteins help fight viral infections and help the body’s defense system against disease. Some M-S patients inject these beta interferon drugs. However, this treatment is very costly. And some patients develop side effects.
Scientists around the world are working to develop new treatments for M-S. Researchers in the United States are carrying out more than twelve studies of possible treatments. Doctors are hopeful that new treatments will help patients with multiple sclerosis in the future.
This SCIENCE IN THE NEWS program was written by Oliver Chanler. This is Steve Ember.
And this is Sarah Long. Join us again next week for more news about science in Special English on the Voice of America.