美国国家公共电台 NPR--Researchers work to create a sense of touch in prosthetic limbs

Researchers work to create a sense of touch in prosthetic limbs

Transcript¹

A team at the University of Pittsburgh is trying to make prosthetic limbs that work like the one in a Star Wars movie.

After Luke Skywalker loses a hand in a lightsaber fight, "They give him this new hand, and you can't tell that it's not his own," says Lee Fisher, a biomedical engineer.

Luke even says "ouch" when a medical droid prods² his prosthetic finger.

"That's our long-term goal," Fisher says, "to restore sensory³ feedback from the missing limb."

The human brain relies on a constant stream of tactile⁴ information to carry out basic tasks, like holding a cup of coffee. Yet some of the most advanced motorized limbs — including those controlled solely⁵ by a person's thoughts — don't provide this sort of feedback. As a result, even state-of-the-art prosthetics can often frustrate⁶ their users.

Fisher is one of more than 80 scientists, staff and trainees⁷ at the university's Rehab Neural⁸ Engineering Labs who is working to add the sensation of touch to prosthetics. The goal is to equip artificial hands and feet with sensors⁹ that are linked to a person's own nervous system.

Fisher's lab, for example, is linking prosthetic arms and legs to a device implanted in a person's spine¹⁰.

"It basically looks like a spaghetti noodle," he says. "They can be inserted through a needle, so it's a pretty minimally¹¹ invasive process to put them in."

The device was originally designed to ease chronic¹² pain by delivering electrical pulses to the spinal¹³ cord. But Fisher's lab is using it to relay information from sensors to a prosthetic hand or foot.

The trick is to stimulate¹⁴ the same nerve fibers¹⁵ that were once connected to the person's own limb, Fisher says. That requires some trial and error.

"The first thing we do is just try and understand, 'What did the stimulation¹⁶ feel like?'" he says. "Can we generate a sensation that feels like it's coming from their missing hand or from their missing foot? Can we change how intense it feels?"

"There's no hand there, but I can feel it"

A study of four people suggests the answer is yes. Pat Bayne, a participant whose right arm was amputated to stop an infection, describes what the stimulation feels like in a video made by the university: "I know there's no hand there, but I can feel it," she says. "They can make the palm of my hand feel like it's the palm of my hand. It's pretty exciting."

Participants also report that the stimulation reduces the perception of pain coming from a missing limb — a common problem after an amputation¹⁷.

Fisher's team is now also working to use the spinal implants¹⁸ to provide sensory feedback from artificial legs and feet.

The addition could make these prosthetic limbs more useful, Fisher says, because we rely on constant feedback from our feet just to stay upright. "We're basically like an upside down pendulum¹⁹ that you have to keep moving around to maintain balance," he says.

Preliminary results suggest that at least one person using a prosthetic foot was helped by the feedback.

"We saw what look like improvements in her balance control during standing²⁰, her stability while she's walking, and also maybe some improvements in her confidence as well," Fisher says.

Reaching out with the mind alone

People who are paralyzed could also benefit from artificial limbs with a sense of touch, says Jennifer Collinger, an associate professor in the university's department of physical medicine and rehabilitation²¹.

For several years, the Pittsburgh group has been working with paralyzed volunteers who have learned to control a robotic arm using just their thoughts.

The goal is to develop technology that would allow them to be more independent, Collinger says. "What we're moving toward is being able to feed yourself, being able to make a meal, being able to get dressed," she says.

But tasks like that will be difficult if a person has to rely solely on their eyes to know what the robotic arm is doing. So the Pittsburgh scientists are adding the same kind of touch sensors they use to enhance prosthetic arms. But in this case, the sensory information is being delivered directly to the brain instead of going through the spine.

A study of one person found that a sense of touch makes a big difference, says Robert Gaunt, a biomedical engineer.

"It cuts in half the time it takes somebody to pick up objects and move them around," he says. And in some cases, the person completed a task nearly as fast as an able-bodied person.

So far, scientists can only offer a very basic sense of touch to people who use prosthetic limbs.

The feedback is good enough to know when a foot has weight on it or a hand has encountered an object, Gaunt says. But users often describe the sensation as a vibration²², buzzing, tingling²³ or pressure.

"The information we're able to provide is definitely not a perfect replacement²⁴ for what they lost," Fisher says.

The information will improve as new sensors arrive and scientists find better ways to connect them to a person's nervous system, Gaunt says. But it won't match the sensitivity of Luke Skywalker's prosthetic hand anytime soon.

"Our ability to discriminate²⁵ [among] different types of objects, textures²⁶, surfaces, that's a hard problem," Gaunt says. He's hoping, though, that it's not unattainable.

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 prods   

n.刺，戳( prod的名词复数 )；刺激；促使；（用手指或尖物）戳v.刺，戳( prod的第三人称单数 )；刺激；促使；（用手指或尖物）戳

参考例句：

• Electric bulb and socket, with a pair of prods for testing for element shorts and defects. 电灯，插座和一对探针，以供试验电池的短路和检查故障用。 来自辞典例句
• Make off the cuff remarks that are often seen as personal prods. 做出非正规的评价，让人不能接受。 来自互联网

3 sensory   

adj.知觉的，感觉的，知觉器官的

参考例句：

• Human powers of sensory discrimination are limited.人类感官分辨能力有限。
• The sensory system may undergo long-term adaptation in alien environments.感觉系统对陌生的环境可能经过长时期才能适应。

4 tactile   

adj.触觉的，有触觉的，能触知的

参考例句：

• Norris is an expert in the tactile and the tangible.诺里斯创作最精到之处便是，他描绘的人物使人看得见摸得着。
• Tactile communication uses touch rather than sight or hearing.触觉交流，是用触摸感觉，而不是用看或听来感觉。

5 solely   

adv.仅仅，唯一地

参考例句：

• Success should not be measured solely by educational achievement.成功与否不应只用学业成绩来衡量。
• The town depends almost solely on the tourist trade.这座城市几乎完全靠旅游业维持。

6 frustrate   

v.使失望；使沮丧；使厌烦

参考例句：

• But this didn't frustrate Einstein.He was content to go as far as he could.但这并没有使爱因斯坦灰心，他对能够更深入地研究而感到满意。
• They made their preparations to frustrate the conspiracy.他们作好准备挫败这个阴谋。

7 trainees   

新兵( trainee的名词复数 )； 练习生； 接受训练的人； 训练中的动物

参考例句：

• We've taken on our full complement of new trainees. 我们招收的新学员已经满额了。
• The trainees were put through an assault course. 受训人员接受了突击训练课程。

8 neural   

adj.神经的，神经系统的

参考例句：

• The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
• The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

9 sensors   

n.传感器，灵敏元件( sensor的名词复数 )

参考例句：

• There were more than 2000 sensors here. 这里装有两千多个灵敏元件。 来自《简明英汉词典》
• Significant changes have been noted where sensors were exposed to trichloride. 当传感器暴露在三氯化物中时，有很大变化。 来自辞典例句

10 spine   

n.脊柱，脊椎；(动植物的)刺；书脊

参考例句：

• He broke his spine in a fall from a horse.他从马上跌下摔断了脊梁骨。
• His spine developed a slight curve.他的脊柱有点弯曲。

11 minimally   

最低限度地，最低程度地

参考例句：

• Food spoilage problems occur with minimally processed, concentrated frozen citrus products. 食品的变质也发生在轻微加工的、浓缩冷冻的柑橘制品中。
• So, minimally, they are responsible for such actions and omissions. 所以，至少来说，他们要对这样的行为和忽略负责。

12 chronic   

adj.(疾病)长期未愈的，慢性的；极坏的

参考例句：

• Famine differs from chronic malnutrition.饥荒不同于慢性营养不良。
• Chronic poisoning may lead to death from inanition.慢性中毒也可能由虚弱导致死亡。

13 spinal   

adj.针的，尖刺的，尖刺状突起的；adj.脊骨的，脊髓的

参考例句：

• After three days in Japan,the spinal column becomes extraordinarily flexible.在日本三天，就已经使脊椎骨变得富有弹性了。
• Your spinal column is made up of 24 movable vertebrae.你的脊柱由24个活动的脊椎骨构成。

14 stimulate   

vt.刺激，使兴奋；激励，使…振奋

参考例句：

• Your encouragement will stimulate me to further efforts.你的鼓励会激发我进一步努力。
• Success will stimulate the people for fresh efforts.成功能鼓舞人们去作新的努力。

15 fibers   

光纤( fiber的名词复数 )； （织物的）质地； 纤维，纤维物质

参考例句：

• Thesolution of collagen-PVA was wet spined with the sodium sulfate as coagulant and collagen-PVA composite fibers were prepared. 在此基础上，以硫酸钠为凝固剂，对胶原-PVA共混溶液进行湿法纺丝，制备了胶原-PVA复合纤维。
• Sympathetic fibers are distributed to all regions of the heart. 交感神经纤维分布于心脏的所有部分。

16 stimulation   

n.刺激，激励，鼓舞

参考例句：

• The playgroup provides plenty of stimulation for the children.幼儿游戏组给孩子很多启发。
• You don't get any intellectual stimulation in this job.你不能从这份工作中获得任何智力启发。

17 amputation   

n.截肢

参考例句：

• In ancient India,adultery was punished by amputation of the nose.在古代印度，通奸要受到剖鼻的处罚。
• He lived only hours after the amputation.截肢后，他只活了几个小时。

18 implants   

n.（植入身体中的）移植物( implant的名词复数 )

参考例句：

• Hormone implants are used as growth boosters. 激素植入物被用作生长辅助剂。 来自《简明英汉词典》
• Perhaps the most far-reaching project is an initiative called Living Implants From Engineering (LIFE). 也许最具深远意义的项目，是刚刚启动的建造活体移植工程 (LIFE)。 来自英汉非文学 - 生命科学 - 医学的第四次革命

19 pendulum   

n.摆，钟摆

参考例句：

• The pendulum swung slowly to and fro.钟摆在慢慢地来回摆动。
• He accidentally found that the desk clock did not swing its pendulum.他无意中发现座钟不摇摆了。

20 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

21 rehabilitation   

n.康复，悔过自新，修复，复兴，复职，复位

参考例句：

• He's booked himself into a rehabilitation clinic.他自己联系了一家康复诊所。
• No one can really make me rehabilitation of injuries.已经没有人可以真正令我的伤康复了。

22 vibration   

n.颤动，振动；摆动

参考例句：

• There is so much vibration on a ship that one cannot write.船上的震动大得使人无法书写。
• The vibration of the window woke me up.窗子的震动把我惊醒了。

23 tingling   

v.有刺痛感( tingle的现在分词 )

参考例句：

• My ears are tingling [humming; ringing; singing]. 我耳鸣。 来自《现代汉英综合大词典》
• My tongue is tingling. 舌头发麻。 来自《现代汉英综合大词典》

24 replacement   

n.取代，替换，交换；替代品，代用品

参考例句：

• We are hard put to find a replacement for our assistant.我们很难找到一个人来代替我们的助手。
• They put all the students through the replacement examination.他们让所有的学生参加分班考试。

25 discriminate   

v.区别，辨别，区分；有区别地对待

参考例句：

• You must learn to discriminate between facts and opinions.你必须学会把事实和看法区分出来。
• They can discriminate hundreds of colours.他们能分辨上百种颜色。

26 textures   

n.手感( texture的名词复数 )；质感；口感；（音乐或文学的）谐和统一感

参考例句：

• I'm crazy about fabrics textures and colors and designs. 我喜欢各式各样的纺织物--对它的质地，色彩到花纹图案--简直是入了迷。 来自辞典例句
• Let me clear up the point about the textures. 让我明确了一点有关的纹理。 来自互联网