VOA慢速英语2009年-SCIENCE IN THE NEWS - Alzheimer's Disease:（在线收听）

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

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And I'm Barbara Klein. Today we tell about Alzheimer's disease. More than a century after its discovery, Alzheimer's disease is still destroying people's brains. The cause remains unknown.

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September twenty-first is World Alzheimer's Day. The theme for the observance this year is "Diagnosing Dementia: See It Sooner." The goal is early identification of the disease so those affected get the treatment they need.

Around the world, there will be walks to raise money for medical research. Training courses and educational meetings also are planned.

In the United States, for example, more than twenty thousand teams are preparing for what organizers call memory walks. Singapore will hold public events in at least three languages: English, Malay and Mandarin. And, Barbados will mark World Alzheimer's Day with events like a religious service, a health fair and performances by musicians.

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Carin Kay Martin and her mother, who has Alzheimer's disease, share an apartment in Sacramento, California

An estimated thirty million people around the world have Alzheimer's disease. In the United States alone, more than five million people are said to suffer from this slowly increasing brain disorder.

Alzheimer's affects memory and personality -- those qualities that make a person an individual. There is no known cure. Victims slowly lose their abilities to deal with everyday life.

At first, they forget simple things, like where they put something or a person's name. As time passes, they forget more and more. They forget the names of their husbands, wives or children. Then they forget who they are.

Finally, they remember almost nothing. It is as if their brain dies before the other parts of the body. Victims of Alzheimer's do die from its effects or conditions linked to it. But death may not come for many years.

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Alzheimer's disease is the most common disability or mental sickness called dementia. Dementia is the loss of thinking ability that is severe enough to interfere with daily activities. It is not a disease itself. Instead, dementia is a group of signs of some conditions and diseases.

Some kinds of dementia can be cured or corrected. This is especially true if they result from drugs, infection, sight or hearing problems, head injury, and heart or lung problems. Other kinds of dementia can be corrected by changing levels of hormones or vitamins in the body. However, brain cells of Alzheimer's victims die and are not replaced.

Victims can become angry and violent as the ability to think and remember decreases. They sometimes shout and move with no purpose or goal. Media reports tell about older adults found walking in places far from their homes. They do not know where they are or where they came from. These people often are suffering from Alzheimer's disease.

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Alzheimer's generally develops differently in each person. Yet some early signs of the disease are common. The victims may not recognize changes in themselves. Others see the changes and struggle to hide them.

Probably the most common early sign is short-term memory loss. The victim cannot remember something that happened yesterday, for example. Also, victims of the disease have increasing difficulty learning and storing new information. Slowly, thinking becomes much more difficult. The victims cannot understand a joke, or cannot cook a meal, or perform simple work.

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Another sign of the disease is difficulty solving simple problems. Alzheimer's patients might not know what to do if food on a stove is burning. Also, people have trouble following directions or finding their way to places they have known all their lives.

Yet another sign is struggling to find the right words to express thoughts or understand what is being discussed. Finally, people with Alzheimer's seem to change. Quiet people may become noisy and aggressive. They may easily become angry and lose their ability to trust others.

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Alzheimer's disease normally affects people more than sixty-five years old. But rare cases have been discovered in people younger than fifty.

Alzheimer's is identified in only about two percent of people who are sixty-five. But the risk increases to about twenty percent by age eighty. By eighty five or ninety, half of all people are found to have some signs of the disease.

Alzheimer's affects people of all races equally. Yet women are more likely to develop the disease than men. This is partly because women generally live longer than men.

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There is no one, simple test to show if someone has Alzheimer's disease. Social workers and mental health experts sometimes test for memory and judgment. Patients may be asked to identify smells like smoke, natural gas or fruits. Some scientists say a weakened ability to identify smells may be involved. They believe it might show possible development of Alzheimer's.

Doctors who suspect a patient has Alzheimer's must test the person for many other physical problems first. Alzheimer's is considered if the tests fail to show the existence of other problems. The only way to be sure a person has Alzheimer's is to examine the victim's brain after death.

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People who care for Alzheimer's patients may become extremely tired physically and emotionally. Families often can get advice and emotional support from local groups. The Alzheimer's Disease Education and Referral Center and the Alzheimer's Association provide information and support.

Another group, Alzheimer's Disease International, lists ten symptoms of the disease on its Web site. The list shows the difference between these signs of normal aging and the possibility of developing Alzheimer's.

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Patients cannot fully recover from the disease. But many can be helped by medicine. That is especially true if the disease is found early.

America's Food and Drug Administration has approved several drugs to treat symptoms of the disease. The drugs are of two kinds. A doctor must order these medicines for patients. Most are called cholinesterase inhibitors.

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Cholinesterase inhibitors may work by protecting a chemical messenger needed for brain activities. They are meant to treat memory, thinking, language, judgment and other brain activity. They are used for mild to moderate cases of the disease.

The second kind of drug has a long name. It is represented by the drug memantine. This medicine seems to work by governing the activity of a chemical involved in information processing, storage and memory. It treats patients with moderate to severe Alzheimer's.

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The British writer Iris Murdoch died of Alzheimer's disease. She said it was a dark and terrible place.

The two thousand-seven film "Away From Her" tells what happens to one marriage when a partner suffers from the disease. Julie Christie was nominated for the Academy Award for Best Actress for playing the patient. Listen as she describes the pain of her mental condition.

JULIE CHRISTIE: "Half the time I wander around looking for something I can't remember what it is. Everything is gone."

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A healthy brain, left, and a brain with Alzheimer's

It has been more than a century since a German doctor, Alois Alzheimer, told about a dementia patient whose brain was studied after death. Her brain had sticky structures and nerve cells that appeared to be mixed together.

Later studies showed these nerves are made of a protein that changes so it sticks together in groups. The sticky structures were shown to be amyloid plaques.

Scientists are still not sure what causes Alzheimer's disease. The leading theory blames amyloid plaques. Still, a theory exists that amyloid plaques are an effect of the disease, not the cause.

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Work continues on possible genetic causes. This month, two teams of European researchers said they identified new genetic markers linked to Alzheimer's disease. The teams worked separately. Their findings were reported in the journal Nature Genetics.

The newly-found genetic markers may affect a person's risk of developing Alzheimer's. Until now, only four genes had been linked with the disease. They provided a better understanding of the disease process, but no immediate treatment.

Many more studies are being done to find the causes and treatment of Alzheimer's.

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This SCIENCE IN THE NEWS program was written by Jerilyn Watson. Our producer was Brianna Blake. I'm Barbara Klein.

VOICE ONE:

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