Parkinson's Disease

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2005-2-7

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VOICE ONE:

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

VOICE TWO:

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

VOICE ONE:

Many people around the world live
with Parkinson's disease. In the United States, Parkinson's affects
about five hundred thousand people. There has been recent interest
in the disease because of some of those affected are very well
known.

When Karol Wojtyla was elected pope in nineteen seventy-eight, he
changed the image of the leader of the Roman Catholic Church. The
new pope, John Paul the second, was known as a man who liked
physical exercise. He swam and walked great distances.

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

However, as both men grew older, they began to change. Their
energy began to disappear. Their movements became slower. Their
faces seemed to be made of stone. Age makes all people lose the
energy they had when they were younger. However, it was not age that
changed these men so much. Their physical changes were caused by a
sickness 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 called
the substantia nigra. The cells slowly lose their ability to produce
a chemical called dopamine. The reduced levels of dopamine can
result in one or more of the general signs or symptoms of
Parkinson's disease.

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

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

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VOICE ONE:

Parkinson's disease is named after James Parkinson. He was a
British doctor who first described the disease in
Eighteen-Seventeen. But Doctor Parkinson did not know what caused
it.

During the nineteen sixties, research scientists discovered
chemical and other changes in the brains of people suffering from
the disease. These discoveries led to medicines to treat Parkinson's
disease. 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 the
disease attempt to link it to some cause they can identify. These
can include an accident, a medical operation, or emotional problems.

Most doctors, however, reject the idea of any direct link between
these events or problems and Parkinson's disease. The doctors note
that other people with similar problems do not develop a movement
disorder such as Parkinson's disease. However, doctors say such
events or problems may cause signs of the disease to be seen earlier
than normal.

VOICE ONE:

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

The disease encephalitis also can cause movement problems and
other disorders like those of Parkinson's disease. In the early
twentieth century, encephalitis spread to many parts of the world.
Many victims of the disease had symptoms similar to Parkinson's
disease. This led to scientific investigations into the possibility
that a virus caused Parkinson's disease.

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

VOICE TWO:

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

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

VOICE ONE:

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

Most of those suffering from the disease are older people. It
reportedly affects one of every one-hundred people over sixty years
old. However, fifteen percent of patients develop the disease before
they are fifty years old. Also, it affects men a little more often
than it affects women. And Parkinson's disease can be found among
people in all parts of the world.

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VOICE TWO:

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

Perhaps the drug most commonly used to treat the disease is
levodopa. When it reaches the brain, levodopa is changed to
dopamine. It replaces the dopamine lacking in patients with
Parkinson'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 effects
include feeling extremely sick to the stomach. To prevent this from
happening, other substances can be combined with levodopa.

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

VOICE ONE:

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

More recently, improved technology has increased the chances of
successful pallidotomies. The operation involves placing electrical
devices directly on the brain. These devices target cells in the
area that cause unwanted movements of the body. The most serious
risk from this treatment is the possibility of the patient suffering
a stroke.

VOICE TWO:

The most recent development in treatment of Parkinson's disease
is brain tissue transplants. This involves replacing tissue in areas
of the brain that cause symptoms of the disease. Early experiments
involved brain tissue from unborn babies. Doctors said the method
appeared to have successful results.

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

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

VOICE ONE:

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

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VOICE TWO:

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

VOICE ONE:

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