People who have lost the ability to understand or use words due to brain damage are called aphasics（失语症患者）. Such patients can be extremely good at something else. From the changing expressions on speakers’ faces and the tones of their voices, they can tell lies from truths.
Doctors studying the human brain have given a number of examples of this amazing power of aphasics. Some have even compared this power to that of a dog with an ability to find out the drugs hidden in the baggage.
Recently, scientists carried out tests to see if all that was said about aphasics was true. They studied a mixed group of people. Some were normal； others were aphasics. It was proved that the aphasics were far ahead of the normal people in recognizing false speeches — in most cases, the normal people were fooled by words, but the aphasics were not.
Some years ago, Dr. Oliver Sacks wrote in his book about his experiences with aphasics. He mentioned a particular case in a hospital. Some aphasics were watching the president giving a speech on TV. Since the president had been an actor earlier, making a good speech was no problem for him. He was trying to put his feelings into every word of his speech.
But his way of speaking had the opposite effect on the patients. They didn’t seem to believe him. Instead, they burst into laughter. The aphasics knew that the president did not mean a word of what he was saying. He was lying!
Many doctors see aphasics as people who are not completely normal because they lack the ability to understand words. However, according to Dr. Sacks, they are more gifted than normal people. Normal people may get carried away by words. Aphasics seem to understand human expressions better, though they cannot understand words.

由于大脑的损伤而失去理解和使用语言能力的人们，被称做失语证患者。这些患者在其它某些方面会非常优秀。从讲话者表情上的变化和说话时的语调，他们可以看出这些人是否在说假话。
研究人脑的医生们，对失语症患者的这一神奇力量给出了一些例子。有些医生甚至把他们的这一能力与能够从行李中找出毒品的狗相比。
最近，为了证实失证症患者的这一能力是否真实，科学家们做了一些实验。他们对一些人群进行了研究，这些人里有些是正常人， 有些是失语症患者。实验证明，失语症患者辨别虚假演讲的能力要远远超过正常人，在大多数情况下，正常人总是被言辞所愚弄，但失语症患者就不会。
几年前，Oliver Sacks博士在他的书里描述了他对失语症患者的看法。他提到了一家医院里的一个典型案例。一些失证症患者正通过电视观看总统演讲，因为这位总统早年做过演员（不会是里根吧，哈哈...），发表一份好的演讲对他来说一点问题都没有，他正努力的把所有的情感都倾注到他的话语中，但他讲话的样子却在失语者身上起到了相反的作用，这些人好象并不相信他，反而却爆发了一阵大笑。这些失语症患者知道，总统所说的并不是真心话，他在说谎！
有许多医生并不把失语症患者当正常人看待，因为他们缺乏理解语言的能力。然而，Sacks博士认为，他们比正常人更具有天才性。正常人有时会被言语牵着走，尽管听不懂语言，但失语症患者能更好的理解人类的表情。