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　　Memory loss and mental confusion are the first overt¹ signs of Alzheimer's Disease, an incurable² and fatal brain ailment³.
记忆力丧失和心智混乱，是老年痴呆症最先出现的症状。这是一种无药可治的脑部致命疾病。
But scientists are starting to find evidence of the disease long before symptoms appear. In the latest research, MRI scans show telltale signs in the brain a decade before memory and thinking are affected⁴.
但是，科学家们发现了远在这些症状出现之前就开始有的先兆。在最新的一项研究中，核磁共振成像扫描显示出脑部在记忆及思考能力受到影响前10年就已出现的迹象。
The pace of research aimed at understanding and preventing or treating Alzheimer's has been frustratingly⁵ slow.
为了了解、预防或治疗老年痴呆症的研究步调，缓慢得令人沮丧。
A number of medicines have reached the market in recent years, but at best they only slow the progression of the disease.
近年来有些药物开始上市，但是那些药最多只能延缓这种疾病的发展。
Some researchers think that drugs may be more effective if they're given sooner, before symptoms become apparent.
有些专家认为，如果在出现明显症状之前，及早进行药物治疗，效果可能会好一些。
A researcher at Harvard Medical School, Bradford Dickerson, is exploring an imaging technique that can identify characteristics of the brain that might signal the mental decline to come years later.
哈佛大学医学院的布拉德福德·迪克森正在研究一种成像技术，用来辨识大脑中一种可能预示多年后心智下降的特殊现象。
"So we wanted to test MRI, which is something that we think would potentially be more accessible to people if we end up needing to screen large groups of older subjects for these kinds of changes," Dickerson says.
迪克森说：“我们希望试验核磁共振。我们想，如果今后需要对大量上年纪的人进行筛查，以发现这类改变，很可能就会更多地使用核磁共振成像技术。”
In a new study, Dickerson and his colleagues studied a group of men and women starting when they were in their 70s. At the outset, they were given standard tests, and all of them showed normal memory and mental function. They also got an MRI scan of the brain.
在一项新的研究中，迪克森和他的同事对一群70多岁的人进行检查。首先，他们接受一般性的测验。每个人的记忆力和心智功能都正常。他们同时也接受了脑部核磁共振成像扫描。
Around 10 years later, the participants - now in their 80s - were again tested, and now about one out of four showed symptoms of Alzheimer's.
大约10年后，这些参与研究的老人都已经年逾80。他们再度接受检查。这时，大约每四个人中有一人出现老年痴呆的症状。
Going back to the MRI results from a decade or so earlier, the researchers found differences between the group who still had normal memory and those who were cognitively⁶ impaired⁷, differences in Alzheimer's-related parts of the brain.
再回过头来看他们10年前的核磁共振成像扫描，研究人员发现了在记忆力正常和有认知困难的两组人之间的不同。这不同之处出现在大脑中和老年痴呆症有关的部位。
"And it turned out that those areas of the brain were, in subtle ways, smaller in the people who were cognitively normal but over the next eight years or so eventually developed Alzheimer's dementia than the same areas in the brains of people who remained cognitively normal over that period of time."
迪克森说：“结果发现，那些过去有8年时间心智正常、但最后罹患老年痴呆症的人大脑的相关部位，比心智仍旧正常的人，稍微小一点。”
For now, this is just a research finding, but Dickerson sees a time in the not-too-distant future when doctors will tell people of a certain age with no symptoms that it's time to get tested for Alzheimer's.
到目前为止，这只是一项研究中的发现。但是迪克森预见在不久的将来，医生会建议某个年龄段、但还没有老年痴呆症状的病人，提前进行检查。
"I believe that at some point in the next decade or so, we're going to see tests being proposed to be used as screening tools, sort of like colonoscopies are used," Dickerson says. "So that once you get past a certain age, you would undergo this screening test. And I think this MRI method has at least some plausibility⁸ to be one of those kinds of screening tools."
迪克森说：“我相信在今后10年，我们会看到医生建议做这种检查，就像今天的直肠镜检查一样。一旦到了某个年纪，就得接受筛查。我认为，核磁共振成像扫描至少可能称为筛查的手段之一。”
And the hope is that drugs in use now or yet to be developed will make a significant difference when taken before memory and mental function begin to decline.
未来的希望是，现有的或者研发中的药物，将在病人的记忆力和心智功能开始下降之前服用，从而产生不同的效果。