(MUSIC)

VOICE ONE:

This is SCIENCE IN THE NEWS, in VOA Special English. I'm SarahLong.

VOICE TWO:

And I'm Bob Doughty. On our program this week, we tell aboutParkinson's disease, a disorder of the central nervous system.

VOICE ONE:

Many people around the world livewith Parkinson's disease. In the United States, Parkinson's affectsabout five hundred thousand people. There has been recent interestin the disease because of some of those affected are very wellknown.

When Karol Wojtyla was elected pope in nineteen seventy-eight, hechanged the image of the leader of the Roman Catholic Church. Thenew pope, John Paul the second, was known as a man who likedphysical exercise. He swam and walked great distances.

Muhammed Ali also showed great energy and power as he became theboxing champion of the world. He was probably one of the sport'sgreatest competitors of the twentieth century.

However, as both men grew older, they began to change. Theirenergy began to disappear. Their movements became slower. Theirfaces seemed to be made of stone. Age makes all people lose theenergy they had when they were younger. However, it was not age thatchanged these men so much. Their physical changes were caused by asickness known as Parkinson's disease.

VOICE TWO:

Parkinson's disease is a disorder of the central nervous system.It is a disease that makes its victims increasingly unable to move.It affects a small area of cells in the middle of the brain calledthe substantia nigra. The cells slowly lose their ability to producea chemical called dopamine. The reduced levels of dopamine canresult in one or more of the general signs or symptoms ofParkinson's disease.

These symptoms include shaking of the arm or leg on one side ofthe body. Other symptoms are a general slowness of movement, orsevere difficulty in moving the arms and legs. Another is difficultywalking and keeping balanced while standing or walking.

Other signs observed in some people include restricted ordecreased movement of the face. Also, victims of Parkinson's diseasecan feel sad or worried. Victims may swallow less often than normal.And, they may have difficulty forming words while talking.

(MUSIC)

VOICE ONE:

Parkinson's disease is named after James Parkinson. He was aBritish doctor who first described the disease inEighteen-Seventeen. But Doctor Parkinson did not know what causedit.

During the nineteen sixties, research scientists discoveredchemical and other changes in the brains of people suffering fromthe disease. These discoveries led to medicines to treat Parkinson'sdisease. However, the cause of the disease is still a mystery.

VOICE TWO:

Most people have what is called idiopathic Parkinson's disease.Idiopathic means that the cause is unknown. Patients who develop thedisease attempt to link it to some cause they can identify. Thesecan include an accident, a medical operation, or emotional problems.

Most doctors, however, reject the idea of any direct link betweenthese events or problems and Parkinson's disease. The doctors notethat other people with similar problems do not develop a movementdisorder such as Parkinson's disease. However, doctors say suchevents or problems may cause signs of the disease to be seen earlierthan normal.

VOICE ONE:

There are other forms of Parkinson's disease. Some medicines forother problems can cause disorders similar to Parkinson's disease.These include medicines used to treat older people who see thingsthat do not exist. And they include drugs used to treat peoplesuffering from extreme tension or stomach problems.

The disease encephalitis also can cause movement problems andother disorders like those of Parkinson's disease. In the earlytwentieth century, encephalitis spread to many parts of the world.Many victims of the disease had symptoms similar to Parkinson'sdisease. This led to scientific investigations into the possibilitythat a virus caused Parkinson's disease.

However, no evidence was found to support this theory. One reasonfor rejecting the theory is that Parkinson's disease cannot bepassed from one person to another the way other viral diseases can.

VOICE TWO:

Another common theory is that people with Parkinson's diseasecould pass it to their children. There are examples of many membersof families having the disease.

Last month, the publication Lancet reported additional geneticevidence. It said a change in just one gene may affect the risk ofParkinson's disease. Researchers found that one in every sixtypeople with Parkinson's have changes in the gene called L-R-R-K-two.The researchers said the genetic changes could be responsible forfive percent of all cases in people with a family history of thedisorder. They said it also could cause up to two percent ofidiopathic Parkinson's.

VOICE ONE:

Also, a small study suggested that chemical products used to killinsects could increase the risk of the disease. American researchersfound that people who sprayed such products had two times the riskof developing Parkinson's than other people. They found farmers alsohad an increased risk, although much smaller.

Most of those suffering from the disease are older people. Itreportedly affects one of every one-hundred people over sixty yearsold. However, fifteen percent of patients develop the disease beforethey are fifty years old. Also, it affects men a little more oftenthan it affects women. And Parkinson's disease can be found amongpeople in all parts of the world.

(MUSIC)

VOICE TWO:

Parkinson's disease does not cause death for those suffering fromthe condition. New treatments to ease symptoms of the disease makeit possible for many patients to continue to live almost normally.Patients who have lost their ability to do many things may be ableto regain some of their old abilities with treatment.

Perhaps the drug most commonly used to treat the disease islevodopa. When it reaches the brain, levodopa is changed todopamine. It replaces the dopamine lacking in patients withParkinson's disease.

Levodopa helps deal with the signs of the disease. It does not,however, prevent more changes in the brain caused by the disease.Levodopa can produce bad effects in some people. These side effectsinclude feeling extremely sick to the stomach. To prevent this fromhappening, other substances can be combined with levodopa.

Most other drugs used to treat Parkinson's disease are designedto increase the amount of dopamine in the brain.

VOICE ONE:

Another way of treating Parkinson's disease is a medicaloperation. One such operation is called a pallidotomy. It was usedoften in the past to treat the disease. However, it was used lessoften after the discovery of levodopa.

More recently, improved technology has increased the chances ofsuccessful pallidotomies. The operation involves placing electricaldevices directly on the brain. These devices target cells in thearea that cause unwanted movements of the body. The most seriousrisk from this treatment is the possibility of the patient sufferinga stroke.

VOICE TWO:

The most recent development in treatment of Parkinson's diseaseis brain tissue transplants. This involves replacing tissue in areasof the brain that cause symptoms of the disease. Early experimentsinvolved brain tissue from unborn babies. Doctors said the methodappeared to have successful results.

However, the experiments became a subject of moral debates amongpersons opposed to the ending of unwanted pregnancies.

Researchers have begun working with genetically changed cells anddifferent animal cells that can be made to produce dopamine. Still,most doctors agree that such operations should be considered onlyafter it is clear that drugs are not effective in dealing with thesigns of Parkinson's disease.

VOICE ONE:

There is no way to prevent or cure Parkinson's disease. So, thevictims of the disease need help in many ways. Throughout the world,there are groups that provide education and support services forpatients and their families learning to live with the disease.

(MUSIC)

VOICE TWO:

This SCIENCE IN THE NEWS program was written by Oliver Chanlerand Caty Weaver. This is Bob Doughty.

VOICE ONE:

And this is Sarah Long. Join us again next week for more newsabout science in Special English on the Voice of America.