Level 5 Reading 7B

Reading 7B

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HUMAN BIONICS Amanda Kitts is mobbed by four- and five-year-olds as she enters the classroom. "Hey, kids, how're my babies today?" she says, patting shoulders and ruffling, hair. Slender and energetic, she has operated this Knoxville, Tennessee, daycare center and two others for almost 20 years. She crouches down to talk to a small girl, putting her hands on her knees. "The robot arm!" several kids cry. "You remember this, huh?" says Kitts, holding out her left arm. As she turns her hand palm up, there is a soft whirring sound. If you weren't paying close attention, you'd miss it. She bends her elbow, accompanied by more whirring. "Make it do something silly!" one girl says. "Silly? Remember how I can shake your hand?" Kitts says, extending her arm and rotating her wrist. A boy reaches out, hesitantly, to touch her fingers. What he brushes against is flesh-colored plastic, fingers curved slightly inward. Underneath are three motors, a metal framework, and a network of sophisticated electronics. The assembly is topped by a white plastic cup midway up Kitts's biceps, encircling a stump that is almost all that remains from the arm she lost in a car accident in 2006. Almost all, but not quite. Within her brain, below the level of consciousness, lives an intact image of that arm—a phantom. When Kitts thinks about flexing her elbow, the phantom moves. Impulses racing down from her brain are picked up by electrode sensors in the white cup and converted into signals that turn motors, and the artificial elbow bends. "I don't really think about it. I just move it," says Kitts, who uses both this standard model and a more experimental arm with even more control. "After my accident, I felt lost. These days I'm just excited all the time, because they keep on improving the arm. One day I'll be able to feel things with it and clap my hands together in time to the songs my kids are singing." Kitts is one of "tomorrow's people," a group whose missing or ruined body parts are being replaced by devices embedded in their nervous systems that respond to commands from their brains. The machines they use are called neural prostheses or— using a term made popular by science fiction writers—bionics. The kind of prosthesis that Amanda Kitts uses is controlled by her brain. A technique called targeted muscle reinnervation uses nerves remaining after an amputation to control an artificial limb. It was first tried in a patient in 2002. Four years later, Tommy Kitts, Amanda's husband, read about the research, which took place at the Rehabilitation Institute of Chicago (RIC). His wife lay in the hospital at the time; the truck that had crushed her car had also crushed her arm, from just above the elbow down. "I was angry, sad, depressed; I just couldn't accept it," she says. But the news Tommy brought her about the Chicago arm gave her some reassurance, and some hope. "It seemed like the best option out there, a lot better than motors and switches," Tommy says. "Amanda actually got excited about it." Soon they were on a plane to Illinois. Todd Kuiken, a licensed medical practitioner and biomedical engineer at RIC, was the person responsible for what the institute had begun calling the "bionic arm." He knew that nerves in an amputee's stump could still carry signals from the brain, and he knew that a computer in a prosthesis could direct electric motors to move the limb. However, making the connection was far from straightforward. Nerves conduct electricity, but they can't be spliced together with a computer cable. (Nerve fibers and metal wires are not mutually compatible, and an open wound where a wire enters the body could be a dangerous avenue for infections.) Kuiken needed an amplifier to boost the signals from the nerves, avoiding the need for a direct contact between nerve and wire. He found one in muscles. When muscles tense, they give off an electrical burst strong enough to be detected by an electrode placed on the skin. He developed a technique to reroute severed nerves from their old, damaged spots to other muscles that could give their signals the proper boost. In October 2006, Kitts consented to have Kuiken try out his new technique on her. The first step was to salvage major nerves that once went all the way down her arm. "These are the same nerves that work the arm and hand, but we had to create four different muscle areas to lead them to," Kuiken says. The nerves started in Kittss brain—in the motor cortex, which holds a rough map of the body—but they terminated at the end of her stump. In an intricate operation, a surgeon rerouted those nerves to different regions of Kitts's upper-arm muscles. For months the nerves grew, millimeter by millimeter, moving deeper into their newly assigned homes. "At three months, I started feeling little tingles and twitches," says Kitts, "and by four months, I could actually feel different parts of my hand when I touched my upper arm. I could touch it in different places and feel different fingers." What she was feeling were parts of the phantom arm that were mapped into her brain, now reconnected to flesh. When Kitts thought about moving those phantom fingers, her real upper-arm muscles contracted. BIONIC MAN As scientists work to link machine and mind, artificial bones, organs, joints,and limbs (Parts shaded green and blue) are gaining many of the capabilities of human ones. 1 Images captured by a video camera in glasses are converted to signals and sent wirelessly to an implant in the eye. Electrodes in the eye send the signals to the optic nerve, which sends them to the brain and a person is able to "see" the images. 2 Implants stimulate nerves inside the ear, allowing people who are partially or completely deaf to hear. 3 Signals are sent from the brain to the bionic arm via electrodes attache a to nerves in the injured arm. The result: a person is able to grasp and manipulate objects. 4 A bionic ankle copies the action of a real one by pushing the wearer forward, helping the person to walk again.

人体仿生学 Amanda Kitts走进教室时被四五岁的孩子团团围住。 “嘿，孩子们，我的孩子们今天怎么样？”她拍着肩膀，皱着头发说。 她身材苗条，精力充沛，在田纳西州诺克斯维尔经营这家日托中心和另外两家日托中心近20年。 她蹲下来和一个小女孩说话，把手放在膝盖上。 “机器人手臂！”几个孩子哭着说。 “你还记得这个，对吧？”基茨伸出左臂说。 当她抬起手掌时，传来一阵轻柔的旋转声。 如果你没有密切关注，你会错过的。 她弯下腰，伴随着更多的旋转声。 “让它做点傻事！”一个女孩说。 基茨说：“傻？还记得我怎么能和你握手吗？”， 她伸出手臂，转动手腕。 一个男孩迟疑地伸手去摸她的手指。 他碰到的是肉色的塑料，手指微微向内弯曲。 下面是三个电机、一个金属框架和一个复杂的电子网络。 这个组件的顶部是一个白色塑料杯，位于基茨二头肌的中间， 她在2006年的一场车祸中失去了手臂，现在几乎只剩下一根残肢。 几乎全部，但不完全。 在她的大脑中，在意识水平以下，有一个完整的手臂图像——一个幻影。 当基茨考虑弯曲肘部时，幽灵就会移动。 白色杯子里的电极传感器捕捉到了从她大脑中奔涌而下的冲动 并将其转换为转动电机的信号，然后人工弯管。 基茨说：“我真的不去想它。我只是移动它。”， 世卫组织既使用这种标准模型，也使用更具实验性、控制力更强的手臂。 “事故发生后，我感到很失落。 这些天我一直很兴奋，因为他们一直在改善手臂。 有一天，我会用它来感受事物，并随着孩子们唱的歌及时拍手。" 基茨是“明天的人”之一 丢失或毁坏身体部位的群体 它们正被嵌入神经系统的设备所取代，这些设备会对大脑的命令做出反应。 他们使用的机器被称为神经假肢或-- 使用科幻作家流行的一个术语——仿生学。 Amanda Kitts使用的假肢是由她的大脑控制的。 一种称为靶向肌肉神经再支配的技术使用截肢后剩余的神经来控制假肢。 它于2002年首次在患者身上试验。 四年后，阿曼达的丈夫汤米·基茨读到了这项研究， 该活动在芝加哥康复研究所（RIC）举行。 当时他的妻子躺在医院里； 压死她的车的卡车也压死了她的手臂，从肘部以上往下。 她说：“我很生气、很难过、很沮丧；我就是无法接受。”。 但汤米给她带来的关于芝加哥手臂的消息给了她一些安慰和希望。 汤米说：“这似乎是最好的选择，比电机和开关好得多。”。 “阿曼达真的很兴奋。” 不久，他们就登上了飞往伊利诺伊州的飞机。 Todd Kuiken是RIC的执业医师和生物医学工程师， 是该研究所开始称之为“仿生手臂”的负责人 他知道截肢者残端的神经仍然可以携带来自大脑的信号， 他知道假肢中的计算机可以引导电动机移动肢体。 然而，建立联系远非易事。 神经导电，但它们不能用电脑电缆拼接在一起。 （神经纤维和金属线不相互兼容， 电线进入体内的开放性伤口可能是感染的危险途径。） Kuiken需要一个放大器来增强来自神经的信号， 避免了神经和导线之间直接接触的需要。 他在肌肉中发现了一个。 当肌肉紧张时，它们会发出强烈的电脉冲，足以被放置在皮肤上的电极检测到。 他开发了一种技术，可以将切断的神经从陈旧受损的部位重新路由 其他肌肉可以适当地增强它们的信号。 2006年10月，基茨同意让奎肯在她身上尝试他的新技术。 第一步是挽救曾经一直延伸到她手臂的主要神经。 “这些神经与手臂和手的神经相同， 但我们必须创造四个不同的肌肉区域来引导它们，”Kuiken说。 神经起源于Kittss的大脑——运动皮层， 里面有一张尸体的粗略地图，但它们在她的树桩末端终止了。 在复杂的操作中， 一位外科医生将这些神经重新路由到基茨上臂肌肉的不同区域。 几个月来，神经一毫米一毫米地生长，深入到他们新分配的家中。 基茨说：“三个月大的时候，我开始感到轻微的刺痛和抽搐。”， “四个月后，当我触摸上臂时，我实际上可以感觉到手的不同部位。 我可以在不同的地方触摸它，感受不同的手指。" 她感觉到的是被映射到她大脑中的幻影手臂的一部分， 现在重新连接到肉体。 当基茨想到移动那些幻影手指时，她真正的上臂肌肉收缩了。 仿生人 随着科学家们努力将机器和大脑、人造骨骼、器官、关节和四肢联系起来 （绿色和蓝色阴影部分）正在获得人类的许多能力。 1眼镜中的摄像机捕获的图像被转换为信号，并无线发送到眼睛中的植入物。 眼睛中的电极将信号发送到视神经， 它将它们发送到大脑，一个人能够“看到”这些图像。 2植入物刺激耳朵内的神经，使部分或完全失聪的人能够听到声音。 3信号通过附着在受伤手臂神经上的电极从大脑发送到仿生手臂。 结果：一个人能够抓住和操纵物体。 4仿生脚踝通过向前推动佩戴者来复制真实脚踝的动作，帮助人再次行走。

A month later, she was fitted with her first bionic arm, which had electrodes in the cup around the stump to pick up the signals from the muscles. Now the challenge was to convert those signals into commands to adjust the elbow and hand. A storm of electrical noise was coming from the small region on Kitts's arm. Somewhere in there was the signal that meant "straighten the elbow" or "turn the wrist." A microprocessor inserted in the prosthesis had to be programmed to differentiate the right signal and send it to the right motor. Kitts practiced using her arm one floor below Kuiken's office in an apartment set up by occupational therapists. The apartment had a kitchen with a stove, silverware in a drawer, a bed, a closet with hangers, a bathroom, and stairs— things people use every day without a second thought but that pose huge obstacles to someone missing a limb. Watching Kitts make a peanut butter sandwich in the kitchen is a startling experience. With her sleeve rolled back to reveal the plastic cup, her motion is fluid. Her live arm holds a slice of bread, her artificial fingers close on a knife, the elbow flexes, and she swipes peanut butter back and forth. "It wasn't easy at first," she says. "I would try to move it, and it wouldn't always go where I wanted." But she worked at it, and the more she used the arm, the more lifelike the motions felt. What Kitts would really like now is sensation. That would be a big help in many actions, including one of her favorites—gulping coffee. "The problem with a paper coffee cup is that my hand will close until it gets a solid grip. But with a paper cup, you never get a solid grip," she says. "That happened at Starbucks once. It kept squeezing until the cup went 'pop." There are valid reasons for supposing that one day she'll get that sensation, says Kuiken. In partnership with bioengineers at the Johns Hopkins University Applied Physics Laboratory, RIC has been developing a new prototype for Kitts and other patients that not only has more flexibility—more motors and joints— but also has pressure-sensing pads on the fingertips. The pads are connected to small rods that poke into Kitts's stump. The harder the pressure, the stronger the sensation in her phantom fingers. "I can feel how hard I'm grabbing," she says. She can also differentiate between rubbing something rough, like sandpaper, and smooth, like glass, by how fast the rods vibrate. "I go up to Chicago to experiment with it, and I love it," she says. "I want them to give it to me already so I can take it home. But it's a lot more complicated than my take-home arm, so they don't have it completely reliable yet." Today, Kitts has a new, more elastic cup atop her arm that better aligns electrodes with nerves that control the arm. "It means I can do a lot more with the arm," she says. "A new one up in Chicago lets me do lots of different hand grasps—I want that. I want to pick up pennies and hammers and toys with my kids." These are reasonable hopes for a substitute body part, Kuiken says. "We are giving people tools, and they are better than what previously existed. But they are still crude, like a hammer, compared with the complexity of the human body." The work of neural prostheses is extremely delicate, a series of trials filled with many errors. As scientists have learned that it's possible to link machine and mind, they have also learned how difficult it is to maintain that bond. Still, bionics represents a major leap forward, enabling researchers to give people back much more of what they've lost than was ever possible before. "That's really what this work is about: restoration," says Joseph Pancrazio, program director for neural engineering at the National Institute of Neurological Disorders and Stroke. "When a person with a spinal cord injury can be in a restaurant, feeding himself, and no one else notices, that is my definition of success."

一个月后，她安装了第一只仿生手臂， 在残肢周围的杯子里有电极，用来接收肌肉的信号。 现在的挑战是将这些信号转换为调整肘部和手部的命令。 一股强烈的电噪声正从基茨手臂上的小区域袭来。 在某处有一个信号，意思是“伸直肘部”或“转动手腕” 必须对插入假体的微处理器进行编程，以区分正确的信号并将其发送到正确的电机。 基茨在职业治疗师搭建的公寓里，在奎肯办公室楼下一层练习用胳膊。 这套公寓有一个带炉子的厨房、抽屉里的银器、一张床、一个带衣架的壁橱、一间浴室和楼梯-- 人们每天使用的东西都会不假思索，但这会给失去肢体的人带来巨大的障碍。 看着基茨在厨房里做花生酱三明治是一种令人震惊的经历。 她的袖子向后卷，露出塑料杯，动作流畅。 她活生生的手臂拿着一片面包，她的人造手指紧贴着一把刀， 肘部弯曲，她来回滑动花生酱。 “起初并不容易，”她说。 “我会尝试移动它，但它并不总是去我想去的地方。” 但她努力工作，她越是使用手臂，动作就越逼真。 基茨现在真正想要的是感觉。 这对许多行为都有很大的帮助，包括她最喜欢的一种行为——大口喝咖啡。 “纸咖啡杯的问题是，我的手会一直闭着，直到它被牢牢抓住。 但有了纸杯，你永远无法牢牢握住，”她说。 “星巴克曾经发生过这样的事。它一直在挤，直到杯子砰砰直跳。” 奎肯说，有充分的理由认为，总有一天她会有这种感觉。 与约翰·霍普金斯大学应用物理实验室的生物工程师合作， RIC一直在为基茨和其他患者开发一种新的原型 这不仅具有更大的灵活性——更多的电机和关节-- 而且指尖上还有压力感应垫。 这些垫子与刺入基茨树桩的小杆相连。 压力越大，她幻指的感觉就越强烈。 她说：“我能感觉到自己抓得有多难。”。 她还能区分摩擦粗糙的东西，比如砂纸， 由于杆的振动速度，它像玻璃一样光滑。 “我去芝加哥做实验，我喜欢它，”她说。 “我希望他们已经给我了，这样我就可以把它带回家了。 但这比我带回家的手臂复杂得多， 所以他们还没有完全可靠。" 如今，基茨的手臂上有一个新的、更有弹性的杯子，可以更好地将电极与控制手臂的神经对齐。 “这意味着我可以用手臂做更多的事情，”她说。 “芝加哥的一个新项目让我可以做很多不同的握法——我想要这样。 我想和孩子们一起捡便士、锤子和玩具。" 奎肯说，这些是对替代身体部位的合理希望。 “我们正在给人们提供工具，它们比以前更好。 但与人体的复杂性相比，它们仍然像锤子一样粗糙。" 神经假体的工作非常精细，一系列的试验充满了许多错误。 正如科学家们所了解到的，将机器和思维联系起来是可能的， 他们也了解到维持这种联系是多么困难。 尽管如此，仿生学代表了一次重大的飞跃， 使研究人员能够比以往任何时候都更多地归还人们失去的东西。 约瑟夫·潘克拉齐奥说：“这就是这项工作的真正意义所在：修复。”， 美国国家神经疾病和中风研究所神经工程项目主任。 “当一个脊髓损伤的人可能在餐馆里时， 养活自己，没有人注意到，这就是我对成功的定义。"

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