科学家已经研究出一种新的检查方法，它可以回答关于老年痴呆症病因的一些重要问题。这种精神衰退性疾病影响了全世界成千上万的人。其症状包括记忆丧失，思维混乱，出现语言和理解方面的障碍。

注释：
1.alzheimer n. 老年痴呆症
symptom n. [医][植]症状, 征兆
degenerative adj. 退化的
diagnosis n. 诊断
protein n. [生化]蛋白质
amyloid beta peptide n. β淀粉状蛋白
hurdle n. 障碍，关卡

New Medical Development: Test for Alzheimer's Disease

Scientists have developed a new test that could answer some crucial questions about the origins of Alzheimer's disease. Symptoms of the degenerative illness - which is thought to affect hundreds of thousands of people around the world - include loss of memory, confusion and problems with speech and understanding. Writing in the journal Nature Medicine, the researchers from Washington University School of Medicine in the United States say the new test could lead to faster diagnosis and better treatment - here's our science reporter Matt McGrath:

Scientists understand that Alzheimer's disease is characterised by a build up in the brain of a protein called amyloid beta peptide.

The memory loss and decline in mental performance associated with the disease occur in people when this protein forms small lumps in the brain. They eventually lead to a complete loss of function.

One of the key scientific hurdles in developing effective treatments for the disease is to understand if the build up of these lumps is caused by the brain producing too much protein or if it's because the brain can't clear it out quickly enough.

In healthy people the brain produces and clears equal amounts, but scientists don't yet know why the process becomes unbalanced in Alzheimer's sufferers.

This is crucial information for researchers trying to develop effective treatments for the disease.

Now scientists at the Alzheimer's disease research centre in Missouri report that they have developed a new test that could answer this question and many others.

In the test the scientists take sample of brain fluid from patients and look for a marker chemical they've injected previously. This marker goes to the brain and brain cells include it in new copies of the protein when they make it - From the brain fluid the scientists can work out how much protein is being produced or cleaned up.

Because this test directly measures the levels of production of the protein that causes the disease, the scientists believe that it could also prove very useful in the early diagnosis of Alzheimer's before the onset of symptoms.

老年痴呆症的新医学进展

科学家已经研究出一种新的检查方法，它可以回答关于老年痴呆症病因的一些重要问题。这种精神衰退性疾病影响了全世界成千上万的人。其症状包括记忆丧失，思维混乱，出现语言和理解方面的障碍。美国华盛顿大学医学院的研究人员在《自然·医学》杂志上发表的论文上介绍说，这项新的检查方法能够加速诊断过程，同时使得治疗更加有效。科学部记者马特·麦格拉思报道。

科学家们已经发现老年痴呆症的特点是大脑中生成一种叫做β淀粉状蛋白的蛋白质。

当这种蛋白质在人脑中形成小块斑点时，就会使人记忆丧失，精神活动退化，最终导致大脑功能完全丧失。

在制定有效治疗方案的过程中，一个关键性的障碍就是要弄清楚这些斑块的成因，是由于大脑产生了过多的蛋白质还是由于大脑不能尽快把这些多余的蛋白质清除出去。

健康人的大脑能产生和清除同样多数量的蛋白质，但是科学家至今不明白为什么老年痴呆症病人的大脑就无法保持这一过程的平衡。

对于研究者来说这是研究有效治疗方法的关键信息。

目前密苏里老年痴呆症研究中心的科学家们宣布他们已经找到了新的检查方法，可以解答包括这个问题在内的很多问题。

在这个方法中，科学家通过提取病人的脑脊髓样本来寻找他们之前注射进去的化学物质，这些化学物质都做过标记。带着标记的化学物质进入大脑并融入到脑细胞所新产生出来的蛋白质中。科学家可以通过脑脊髓发现蛋白质产生和被清理的数量。

因为这个方法直接检测了导致疾病的蛋白质量，所以科学家相信这种方法将有助于在老年痴呆症显著症状出现之前做出早期诊断。