This is SCIENCE IN THE NEWS in VOA Special
English. I'm Barbara Klein.
I'm Bob Doughty. Today we tell about the
latest research and treatments for Parkinson's disease.
is a disease of the central nervous system.
It is a progressive disorder. It
gets worse over time. The disease
affects a small area of cells in the middle of the brain. This area is called the substantia
nigra. The cells slowly lose their
ability to produce a chemical called dopamine.
The decrease in the amount of dopamine can result in
one or more general signs of Parkinson's disease. These include shaking of the hands, arms and
legs. They also include difficulty moving
or keeping balanced while walking or
standing. Also, there may be emotional changes, like feeling depressed
or worried. The symptoms of Parkinson's
differ from person to person. They also
differ in their intensity.
disease is named after James Parkinson.
He was a British doctor who first described this condition in eighteen
seventeen. Doctor Parkinson did not know
what caused it. During the nineteen sixties, medical researchers discovered
changes in the brains of people with the disease. These discoveries led to medicines to treat
the effects of the disease. There is no
cure for Parkinson's and no way to prevent it.
And doctors still are not sure about the cause.
Parkinson's affects more than four
million people around the world. It affects more than one million people in North
America. Most are older adults.
patients have what is called idiopathic Parkinson's disease. Idiopathic means the cause is unknown. People who develop the disease often want to
link it to something they can identify.
This might be a medical operation or extreme emotional tension.
many doctors reject this idea of a direct link to Parkinson's. They point to other people who have similar
experiences and do not develop the disease.
doctors say it is possible that such events might cause symptoms of Parkinson's
to appear earlier than they would have.
have found a link between the disease and some chemical products. Last year, an American study showed such a
link between Parkinson's and pesticides, like those used for killing insects. The study compared three hundred nineteen
Parkinson's patients to more than two hundred family members.
years ago, a European study showed a link between pesticide use and
Parkinson's. This study also found that
serious head injuries also increased a person's risk. Scientists at Aberdeen University in Scotland
collected information about more than nine hundred people with Parkinson's or
similar conditions. They compared this
group to almost two thousand people without the disorder. All the people were asked about their use of
pesticides, chemical fluids and metals like iron. The researchers also collected information about
family history of the disease and head injuries.
Farm workers and
others who said they often used pesticides had a forty-one percent greater risk
of Parkinson's than other people. The
disease was also two and one-half times more common among people who had been
knocked unconscious more than once in their lives. These people temporarily lost consciousness
after suffering a blow to the head.
area of study is family genetics. There
are examples of members of a family having the disease. The National Institutes of Health in the
United States says about fifteen percent of people with Parkinson's have a
family history of the disease. But most cases
involve people with no such family history.
few years ago, researchers completed what they called the first large map to
show genetic links with Parkinson's disease.
The map identifies changes in genes that may increase the risk in some
a gene-testing company announced plans for a large genetic study of Parkinson's
patients. The company, 23andme, was the
idea of Ann Wojcicki.
is the wife of Sergey Brin, who helped create the Internet search engine
Google. He has a gene that increases his
risk of developing Parkinson's. His
mother has the disease. The company is
working with two not-for-profit groups.
They hope to collect DNA from ten thousand Parkinson's patients. The
goal is to search for common genes that may cause the disease.
There is no cure for Parkinson's disease. But improved treatments to ease the effects
of the disease make it possible for many patients to live almost normal
lives. People who have lost their
ability to do many things are sometimes able to regain some of these abilities
most commonly used drug is levodopa. The
National Institutes of Health says levodopa is a chemical found naturally in
plants and animals. When it reaches the
brain, levodopa is changed into dopamine, the chemical that is lacking in
people with the disease.
helps ease the symptoms of Parkinson's.
But it does not prevent more changes in the brain that are caused by the
disease. Long-term use can produce
unwanted effects in some people. These
side effects include feeling sick to the stomach.
To prevent this from happening, levodopa can be
combined with other substances, like carbidopa. The National Institutes of Health says carbidopa delays the changes in
levodopa until it reaches the brain.
drugs used to treat Parkinson's disease act like dopamine. They produce reactions in the nerve cells in
the brain. They can be given alone or in
combination with levodopa. Many of the
possible side effects are similar to those linked with the use of levodopa. They include sleepiness, feeling sick or
having bad dreams.
operation called deep-brain stimulation also is used to treat Parkinson's
disease. Doctors place small electrical
devices deep in the brain. The devices
are connected to a piece of equipment called a pulse generator.
Deep brain stimulation
can reduce the need for levodopa and other drugs. It also helps to reduce symptoms such as
shaking and slowness of movement. Recently,
a report in Science magazine showed how deep-brain stimulation works. It found that the treatment affects neural
wires called axons.
researchers were from Stanford University in California. They used light-sensitive molecules to turn
on and off nerve cells in the deep brain structure of mice. Nothing happened when they turned on the
light in cells in an area of the brain called the subthalamic nucleus. But bursts of electricity on the axons
improved movement in the animals.
separate study found that a less invasive treatment might reduce the symptoms
of Parkinson's. It showed that a
treatment called dorsal column stimulation could re-establish movement in rodents
with Parkinson's-like problems. In the
study, researchers fired bursts of electricity at the animals' spinal cords. Romulo Fuentes of Duke University in North
Carolina led the researchers. He noted
that doctors already use spinal cord stimulation in people to help reduce long-lasting
Scientists are also exploring other experimental
treatments. In March, President Obama
ended restrictions on the use of federal money for research using human embryonic
stem cells. Stem cells from very early
embryos are able to grow into any tissue in the body. Scientists say such cells might be able to
cure or treat diseases like Parkinson's.
But opponents say stem cell experiments are wrong because human embryos
are destroyed. They say this is just
like destroying a human life.
actor Michael J. Fox has had Parkinson's disease for eighteen years. But unlike
most patients, he got the disease as a young man. He is forty-seven now and has many symptoms
of the disease. But Fox still acts on television, writes books and is an
activist for Parkinson's. The Michael J.
Fox Foundation has raised more than one hundred forty-two million dollars to
fund research for better treatments. Michael
J. Fox says he is sure that a cure for Parkinson's disease will be found in the
SCIENCE IN THE NEWS was written by George Grow. Our producer was Brianna Blake.
I'm Barbara Klein.
And I'm Bob Doughty. Transcripts,
MP3s and podcasts of our programs are at voaspecialenglish.com. Join us again next week for more news about
science in Special English on the Voice of America.