《英语流行话题阅读:语境识词3500》Unit 35 关于阿尔茨海默氏病

（单词翻译）

　　Unit 35
About Alzheimer's Disease¹
Dementia is a brain disorder² that seriously affects a person's  ability to carry out daily activities. The most common form of  dementia among older people is Alzheimer's disease (AD), which  involves the parts of the brain that control thought, memory, and  language. Scientists think that as many as 4.5 million Americans  suffer from AD. The disease usually begins after age 60, and risk goes  up with age.
AD is named after Dr. Alois Alzheimer, a German doctor. In  1906, Dr. Alzheimer noticed changes in the brain tissue³ of a woman who  had died of an unusual mental illness. He found abnormal⁴ clumps⁵.  Scientists also have found other brain changes in people with AD.  Nerve⁶ cells die in areas of the brain that are vital to memory and  other mental abilities.
Scientists do not yet fully⁷ understand what causes AD. Age is  the most important known risk factor for AD. Family history is another  risk factor. Scientists believe that genetics may play a role in many  AD cases. Scientists still need to learn more about what causes AD. In  addition to genetics, they are studying education, diet, and  environment to learn what role they might play in the development of  this disease.
AD begins slowly. At first, the only symptom may be mild  forgetfulness. In this stage, people may have trouble remembering  recent events, activities, or the names of familiar people or things.  They may not be able to solve simple math problems. Such difficulties  may be a bother, but usually they are not serious enough to cause  alarm.
However, as the disease goes on, symptoms are more easily  noticed. People in the middle stages of AD may forget how to do simple  tasks, like brushing their teeth or combing their hair. They can no  longer think clearly. They begin to ae problems speaking,  understanding, reading, or writing. Later on, people with AD may  become anxious or aggressive, or wander away from home. Eventually,  patients need total care.
AD is a slow disease, starting with mild memory problems and  ending with severe brain damage. No treatment can stop AD. However,  for some people in the early and middle stages of the disease, some  dugs may help prevent some symptoms from becoming worse for a limited  time. Developing new treatments for AD is an active area of research.  Research has shown that vitamin E, estrogen, and ginkgo biloba slow  the progress of AD.