:阿尔茨海默病的新定义有助于更快识别疾病

New Definition of Alzheimer’s Could Help Identify Disease Sooner

Scientists in the United States have proposed a new way to define Alzheimer’s disease. They want the definition based on biological signs, such as changes in the brain, instead of memory loss and other customary signs of the disease.

The Associated Press says the move is aimed at improving Alzheimer’s research by using more objective, factual measures, like brain imaging tests. The researchers want to choose patients for studies and get them tested sooner, when treatments may have more chance to help.

But it is too soon to use these brain scans and other tests in patient care because U.S. health officials have yet to approve them for that purpose, experts say. For now, American doctors continue to depend on the tools they have long used to study thinking skills to identify most cases.

The new definition will have an important effect: Many more people will be considered to have Alzheimer’s because the biological signs can show up 15 to 20 years before other signs do.

“The numbers will increase dramatically,” said Clifford R. Jack¹ Junior of the Mayo Clinic in Rochester, Minnesota. He said, “There are a lot more cognitively² normal people who have the pathology in the brain who will now be counted as having Alzheimer’s disease.”

Jack is a brain imaging specialist. He led a group of experts who amended³ medical guidance on the disease. The group worked with the U.S. government’s National Institute on Aging and the Alzheimer’s Association, a non-profit group.

The new guidelines were published last week in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.

About Alzheimer’s

About 50 million people worldwide have some form of dementia. The word dementia is a general term for a loss of memory and other mental abilities.

In the United States, about 5.7 million people have Alzheimer’s disease under its current definition. But about one-third of people over age 70 who show no thinking problems actually have brain signs that suggest Alzheimer’s, Jack noted⁴.

There is no cure. Current medicines just temporarily ease signs of the disease. Many hoped-for treatments have failed, and doctors think one reason may be that the studies involved patients who had already suffered too much brain damage.

Dr. Eliezer Masliah is director of the Division of Neuroscience at the Institute on Aging. He said that by the time a doctor identifies a patient as having the disease, it is very late.

He said, “What we’ve realized is that you have to go earlier and earlier,” just as doctors found with treating cancer.

Another problem is that as many as 30 percent of people being tested in Alzheimer’s studies based on behavioral signs did not have the disease. They instead had either other forms of dementia or other medical conditions. That makes it unclear if experimental treatments for Alzheimer’s might help. The new definition aims to improve identification of medical conditions through brain imaging and other tests.

Better Testing

Many other diseases already are defined by biomarkers. Biomarkers are objective health measures. For example, one biomarker for diabetes⁵ is blood sugar level.

Biomarkers for Alzheimer’s disease were not possible until a few years ago, when brain scans and spinal⁶ fluid tests were developed for the purpose. They measure two proteins, amyloid and tau, as well as signs of nerve injury, degeneration and brain shrinkage.

The new guidelines identify use of these biomarkers to measure a patient’s condition as it worsens.

What to do?

People may be worried and want these tests for themselves or a family member now.

Yet the Mayo Clinic’s Clifford Jack advises against doing so. “There’s no proven treatment yet,” he says.

You might find a doctor willing to order them. However, spinal fluid tests are somewhat invasive, and brain scans can cost up to $6,000.

In the United States, health care plans usually do not pay for such tests because they are considered experimental research.

Americans with signs or a family history of dementia, or even healthy people concerned about the risk can consider taking part in one of the many studies being done.

I’m Caty Weaver⁷.

Words in This Story

dramatic – adj. greatly affecting one’s emotions; sudden and extreme

cognitively – adj. of or related to one’s ability to think

pathology – n. the study of diseases and of the changes they cause

degeneration – n. a break down or lowering of effective power

1 jack   

n.插座，千斤顶，男人；v.抬起，提醒，扛举；n.（Jake）杰克

参考例句：

• I am looking for the headphone jack.我正在找寻头戴式耳机插孔。
• He lifted the car with a jack to change the flat tyre.他用千斤顶把车顶起来换下瘪轮胎。

2 cognitively   

参考例句：

• Cognitively,man,the subject of cognition,must classify and categorize the objects. 从认知学角度来看 ，作为认知主体的人对于认知对象必须进行分类和范畴化。 来自互联网
• Cognitively, reference can be studied along with information processing of human mind. 从认知的角度看，要研究人类思维的信息处理过程。 来自互联网

3 Amended   

adj. 修正的 动词amend的过去式和过去分词

参考例句：

• He asked to see the amended version. 他要求看修订本。
• He amended his speech by making some additions and deletions. 他对讲稿作了些增删修改。

4 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

5 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

6 spinal   

adj.针的，尖刺的，尖刺状突起的；adj.脊骨的，脊髓的

参考例句：

• After three days in Japan,the spinal column becomes extraordinarily flexible.在日本三天，就已经使脊椎骨变得富有弹性了。
• Your spinal column is made up of 24 movable vertebrae.你的脊柱由24个活动的脊椎骨构成。

7 weaver   

n.织布工；编织者

参考例句：

• She was a fast weaver and the cloth was very good.她织布织得很快，而且布的质量很好。
• The eager weaver did not notice my confusion.热心的纺织工人没有注意到我的狼狈相。