VOA慢速英语2009-SCIENCE IN THE NEWS - Scientists Re-Examine a Tr（在线收听）

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

VOICE TWO:

And, I'm Shirley Griffith. This week, we will tell about what is said to be the largest study yet of a treatment for Parkinson's disease. We will also tell about a study of young Americans and their use of social Web sites on the Internet.

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VOICE ONE:
　
Sharon Pederson is a Parkinson's patient who received deep brain stimulation.

Recently, researchers in the United States studied the effectiveness of a treatment called deep brain stimulation. It has been used for years to treat patients with Parkinson's disease. The study found that the physical condition of Parkinson's patients often improves after they receive deep brain stimulation. But brain stimulation was also shown to have more side effects than drug treatments.

Parkinson's is a disease of the central nervous system. The disease affects between five hundred thousand and one million five hundred thousand Americans. Doctors confirm about sixty thousand new Parkinson's cases in the United States each year. The disease affects a small area of cells in the middle of the brain. 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 of the general signs of Parkinson's. These include shaking in the hands, arms and legs. They also include muscle tightness and restricted movements. Another symptom is difficulty keeping balanced while standing or walking. Medicine can help patients. Yet it can become less effective as the disease progresses.

VOICE TWO:

Deep brain stimulation uses electricity to shock the brain in areas that help send messages to the body. In Parkinson's patients, these areas of the brain can become blocked. When this happens, the messages give misinformation to the body.

Deep brain stimulation begins by doctors drilling two small holes in the head of the patient. Two thin, electrical wires are then placed in the brain. They are connected under the skin to another wire that leads to a small battery placed in the chest. The device supplies electricity.

Doctors do not know exactly how the brain stimulation works to help patients with Parkinson's. But experts believe the electrical current might help activate nerve cells that are not working correctly.

VOICE ONE:

The study involved two hundred fifty-five Parkinson's patients. It took place at thirteen medical centers across the United States between May of two thousand two and October of two thousand five. The patients kept written records of their physical abilities.

The Journal of the American Medical Association published results of the study. They showed that patients who received deep brain stimulation had better control of their symptoms than those who only took medicine. In fact, the patients who had the treatment reported an average gain of nearly five hours each day of good control of their symptoms. The average gain was zero hours for the other group.

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Deep brain stimulation is not the answer for all Parkinson's patients. Doctors say it is best for patients whose medicines cause side effects or are not working. The treatment is not new. It was first approved for use in the United States in nineteen ninety-seven. However, its effectiveness had never before been compared to that of medicines in a large study.

In the United States, Parkinson's patients can receive deep brain stimulation at about three hundred medical centers. The treatment has been performed about forty thousand times throughout the world.

But several possible side effects make the treatment risky. The side effects include pain in the head, problems speaking and slowed movement. One patient who had the surgery died. However, in many cases, the researchers found the side effects ended within six months. And, some patients said the improvements they experienced were worth the risk.

VOICE ONE:

Deep brain stimulation is also costly. It can cost as much as one hundred fifty thousand dollars. In addition, the battery placed under the skin may require a replacement. This means doctors need to perform another operation.

The company that makes the device, Medtronic, helped to pay for the study. Financial support also came from the United States Department of Veterans Affairs and the National Institute of Neurological Disorders and Stroke.

In addition to people with Parkinson's, the treatment is also being tested for patients with severe depression, lasting pain and epilepsy.

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VOICE TWO:

Social networking services on the Internet are popular in many countries. These services are web sites that help people find others like themselves and create personal identities. Users also can exchange resources and work together.

MySpace is a popular social networking web site in the United States. Recently, researchers found that more than half of young people who use MySpace often discuss high-risk activities. The activities are said to include drug use, sexual behavior and violence.

Two studies exploring the subject were published last month in the Archives of Pediatric and Adolescent Medicine. The MySpace web site is largely available to the public on the Internet. It provides personal web sites to individuals around the world.

VOICE ONE:

In one study, American researchers examined MySpace pages belonging to five hundred eighteen year-olds from the United States. The researchers say the MySpace pages were chosen by chance. They found that forty-one percent of the pages included information about alcohol or drug use. Twenty-four percent discussed sexual behavior. And, fourteen percent included discussion of violence.

The study showed that males were more likely to discuss violence than females on their MySpace pages. Young people who said they were active in religious groups, sports or had other interests were less likely to discuss risky behaviors.

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In the second study, the researchers read MySpace information about one hundred ninety individuals. All of the individuals said they were eighteen to twenty years old. Each person discussed high-risk behavior on the web site.

One of the researchers was Megan Moreno of the University of Wisconsin School of Medicine and Public Health. At the time of the study, she worked at the Seattle Children's Research Institute.

Doctor Moreno sent a message to half the young people. Her e-mail suggested that they change their MySpace page. She also warned them about the risk of sharing personal information. The message also included links to information about diseases spread by sexual activity.

The study found that about fourteen percent of those receiving the e-mail removed sexual behavior information from their site. Among individuals who did not receive a message, about five percent later removed the information. Those who received the message also were more likely to make their MySpace pages private.

VOICE ONE:

In the United States, the Internet is available to more than ninety percent of young people. About half of all young people use social connection web sites, including MySpace and Facebook. MySpace has more than two hundred million profiles or personal pages within its web site. Research suggests about twenty-five percent of all the profiles belong to individuals under age eighteen.

Information written on social web sites is not always true. Still, law enforcement officials have long warned about the dangers of young people being identified by adults wishing to harm them. Parents also worry about the effects that personal information or pictures can have on the child's ability to get jobs or go to college.

Doctor Dimitri Christakis of the Seattle Children's Hospital worked on the study. He suggests that parents educate themselves about the Internet. He suggests they even create their own web pages, and read their children's pages. He says parents have a responsibility to know what their children are including on public web sites.

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VOICE TWO:

This SCIENCE IN THE NEWS program was written by Brianna Blake, who was also our producer. I'm Shirley Griffith.

VOICE ONE:

And I'm Bob Doughty. We would like to hear from you. Write to us at Special English, Voice of America, Washington, DC, two-zero-two-three-seven, USA. Or send your e-mails to [email protected]. Join us again next week for more news about science in Special English on the Voice of America.