FDA Approves First Prosthesis Controlled by Muscle Electrical Signals

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ean Kamen's DEKA Arm is an electronic prosthetic that mimics natural arm and hand movement with an amazing level of finesse. It's controlled by electrical signals from the wearer's muscles. This week, the DEKA Arm became the first muscle-controlled prosthetic approved by the FDA for sale to the general public.

The user controls the DEKA arm by contracting different muscles in the arm or foot. Electromyogram sensors pick up the electrical signal from the wearer's muscles and translate them into any of 10 different complex, multi-joint powered movements. The entire assembly is the same size and weight as a natural limb, and the battery-powered prosthesis offers six different hand grips.

Watch the DEKA Arm in action, performing the type of household tasks that require delicate maneuvers and varying levels of grip: video

The DEKA Arm, developed by Segway inventor Dean Kamen with funding from DARPA, took eight years to go from concept to approval. That's pretty quick considering the traditional "split hook" arm prosthesis has been in use since 1912. The DEKA Arm can be customized for limb loss at the shoulder, mid-bicep, or mid-forearm, though it can't be fitted for amputations at the elbow or wrist.

In the FDA study, 90% of test subjects were able to quickly adapt to using the DEKA Arm for tasks that were impossible with traditional arm prosthetics, like brushing hair and using keys and zippers.

This is a cyborg we can all support. [FDA; DARPA via Engadget]

Image: DARPA

AMPUTEE WITH BIONIC HAND, Dennis Aabo Sorenson, can feel objects

AN amputee with a bionic hand has for the first time been able to feel the texture and shape of objects in his grasp, European researchers say.   
The success of the month-long trial in Italy has energised researchers in the hunt to solve one of the most difficult challenges in prosthetics.
Until now, movable prosthetic hands have returned no sensation to the wearer and have been difficult to control, meaning the user could crush an object while trying to grasp it.
"For the first time we were able to restore real time sensory feeling in an amputee while he was controlling this sensorized hand," said lead author Silvestro Micera.
The study was led by Micera and Stanisa Raspopovic and colleagues at Switzerland's Ecole Polytechnique Federale de Lausanne and the BioRobotics Institute in Pisa, Italy.
Their findings appear in the US peer-reviewed journal Science Translational Medicine.
"When I held an object, I could feel if it was soft or hard, round or square," said Dennis Aabo Sorenson, a 36-year-old man from Denmark who lost his left hand in a fireworks accident.
"I could feel things that I hadn't been able to feel in over nine years," he added, describing the sensation as "incredible." Sorenson was fitted with a bulky mechanical hand that had several advanced sensors in each of the fingertips.
Those sensors delivered electrical signals through wires to several electrodes that were surgically implanted into his upper arm.
Even though his nerves had not been used in nearly a decade, scientists were able to reactivate his sense of touch.
Wearing a blindfold and earplugs for the trial, which took place last year in Rome at Gemelli Hospital, Sorenson found he could tell the difference between a mandarin orange and a baseball.
He could also feel whether he was holding soft tissue, a hard piece of wood, or a flimsy plastic cup.

Sorenson joked that his children called him "The Cable Guy," when they saw all the wires coming out of his arm, hooking him up to the stationary hand, which was posed on a table.
Sorenson's implant was removed after 30 days due to safety restrictions, but experts believe the electrodes could stay in for years without problem.





More tests are ongoing. Researchers are working to refine the sensory abilities of the prosthetic hand and make it portable by miniaturising the electronics.
In the meantime, Sorenson has returned to using his old prosthetic hand, which opens and closes when he squeezes or relaxes a muscle in his arm, but does not allow him to feel what he touches.
Researchers who were not involved with the study said the work offers a promising new step towards a bionic hand, though a mass-market sensory prosthetic is undoubtedly years away.

"This new advance seems to represent another step forward in creating a more precise man-machine interface," said Richard Frieden, assistant professor at the Icahn School of Medicine at Mount Sinai Medical Center in New York.

David Gow, director of rehabilitation engineering services and bio-engineering at NHS Lothian in Scotland, said that although the work involved a single case study, the method appears "practical." "This opens up exciting possibilities for artificial limb users," he added. Link  see more here       video here
source AFP

PRESS RELEASE – SAHLGRENSKA UNIVERSITY HOSPITAL AND CHALMERS   22-03-2013

For the first time an operation has been conducted, at Sahlgrenska University Hospital, where electrodes have been permanently implanted in nerves and muscles of an amputee to directly control an arm prosthesis. The result allows natural control of an advanced robotic prosthesis, similarly to the motions of a natural limb.

A surgical team led by Dr Rickard Brånemark, Sahlgrenska University Hospital, has carried out the first operation of its kind, where neuromuscular electrodes have been permanently implanted in an amputee. The operation was possible thanks to new advanced technology developed by Max Ortiz Catalan, supervised by Rickard Brånemark at Sahlgrenska University Hospital and Bo Håkansson at Chalmers University of Technology.

“The new technology is a major breakthrough that has many advantages over current technology, which provides very limited functionality to patients with missing limbs,” says Rickard Brånemark.

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Big challenges

There have been two major issues on the advancement of robotic prostheses: 1) how to firmly attach an artificial limb to the human body; 2) how to intuitively and efficiently control the prosthesis in order to be truly useful and regain lost functionality.“This technology solves both these problems by combining a bone anchored prosthesis with implanted electrodes,” said Rickard Brånemark, who along with his team has developed a pioneering implant system called Opra, Osseointegrated Prostheses for the Rehabilitation of Amputees. A titanium screw, so-called osseointegrated implant, is used to anchor the prosthesis directly to the stump, which provides many advantages over a traditionally used socket prosthesis. “It allows complete degree of motion for the patient, fewer skin related problems and a more natural feeling that the prosthesis is part of the body. Overall, it brings better quality of life to people who are amputees,” says Rickard Brånemark.

How it works

Presently, robotic prostheses rely on electrodes over the skin to pick up the muscles electrical activity to drive few actions by the prosthesis. The problem with this approach is that normally only two functions are regained out of the tens of different movements an able-body is capable of. By using implanted electrodes, more signals can be retrieved, and therefore control of more movements is possible. Furthermore, it is also possible to provide the patient with natural perception, or “feeling”, through neural stimulation. “We believe that implanted electrodes, together with a long-term stable human-machine interface provided by the osseointegrated implant, is a breakthrough that will pave the way for a new era in limb replacement,” says Rickard Brånemark.

The patient

The first patient has recently been treated with this technology, and the first tests gave excellent results. The patient, a previous user of a robotic hand, reported major difficulties in operating that device in cold and hot environments and interference from shoulder muscles. These issues have now disappeared, thanks to the new system, and the patient has now reported that almost no effort is required to generate control signals. Moreover, tests have shown that more movements may be performed in a coordinated way, and that several movements can be performed simultaneously.

“The next step will be to test electrical stimulation of nerves to see if the patient can sense environmental stimuli, that is, get an artificial sensation. The ultimate goal is to make a more natural way to replace a lost limb, to improve the quality of life for people with amputations,” says Rickard Brånemark.

source: mynewsdesk.com

Mind-Controlled Artificial Limbs Fusing Man and Machine Coming Next Year

By Liat Clark, Wired UK  28-11-12

A postdoctoral student has developed a technique for implanting thought-controlled robotic arms and their electrodes directly to the bones and nerves of amputees, a move which he is calling “the future of artificial limbs”. The first volunteers will receive their new limbs early in 2013.

“The benefits have no precedent,” Max Ortiz Catalan, who carries out research in biomedicine and artificial intelligence at the Chalmers University of Technology in Sweden, told Wired.co.uk. “They will be able to simultaneously control several joints and motions, as well as to receive direct neural feedback on their actions. These features are today not available for patients outside research labs. Our aim is to change that.”

Ordinary myoelectric prostheses work by placing electrodes over the skin to pick up nerve signals that would ordinarily be sent by the brain to the limb. An algorithm then translates these signals, and sends instructions to motors within the electronic limb. Since the electrodes are applied to the skin surface, however, they will undoubtedly encounter countless issues in maintaining the fluid transferal of information back and forth between the brain and the limb. By implanting those electrodes directly to the patient’s nerves, Catalan is hoping to get one step closer than anyone else to replicating natural movement.

“Our technology helps amputees to control an artificial limb, in much the same way as their own biological hand or arm, via the person’s own nerves and remaining muscles,” he said.

Using the Osseointegrated Prosthesis for the Rehabilitation of Amputees (OPRA) method developed by Rickard Brånemark at Sahlgrenska University Hospital in Gothenburg, Catalan and his team plan to forgo traditional sockets in place of bone-anchored prostheses attached via titanium screws. It was a method inspired by Brånemark’s father, who was the first to discover that titanium can fuse with bone tissue.

“The operation will consist of placing neural and muscular electrodes on the patient’s stumps, as well as placing the bidirectional interfaces into the human body.”

A titanium implant acts as the bidirectional interface, transmitting signals from the electrodes, placed on nerves and muscles, to the limb. It is a truer replication of how the arm was designed to work, with information from existing nerves being transferred to the limb and to the implant, where algorithms can translate thought-controlled instructions into movement. It is, Catalan told Wired.co.uk, a “closed loop control” that moves us “one step further to providing natural control of the artificial limb”. Add to this the fact that every finger is motorised and can be individually controlled, and Catalan’s bold statement might just be accurate.

The first surgeries, due to be carried out by Brånemark in January or February 2013, will all be on patients that had limbs amputated several years prior. Asked whether or not this will make success harder, Catalan said it was one question they are looking to answer.

“The possibilities are higher in recent amputation. Our first patients however, have been amputated for several years. This project aims to answer several very interesting scientific questions in neurorehabilitation.”

In preparation, for both the amputees’ learning and the algorithm’s, Catalan has been training his subjects in the lab using virtual reality simulations. “It provides real-time feedback to the patients on their performance executing different motions. It is definitely very important for them to re-learn some motions, and for us to quantitatively qualify our algorithms’ performance.”

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"It's hard for me to give people these devices sometimes," Lipschutz says, "because we just don't know if they will really help." What could help more, he and others at RIC think, is the kind of prosthesis Amanda Kitts has volunteered to test—one controlled by the brain, not by body parts that normally have nothing to do with moving the hand. 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 it on the Internet as his wife lay in a hospital bed after her accident. The truck that had crushed her car had also crushed her arm, from just above the elbow down.

Kuiken needed an amplifier to boost the signals from the nerves, avoiding the need for a direct splice. He found one in muscles. When muscles contract, 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 Kuiken set about rewiring Amanda Kitts. 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 Kitts's brain, in the motor cortex, which holds a rough map of the body, but they stopped at the end of her stump—the disconnected telephone wires. 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 new homes.

"At three months I started feeling little tingles and twitches," says Kitts. "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.

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 move 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 housed in the prosthesis had to be programmed to fish out the right signal and send it to the right motor.

Finding these signals has been possible because of Kitts's phantom arm. In a lab at the RIC Blair Lock, a research engineer, fine-tunes the programming. He has Kitts slide off the artificial arm so that he can cover her stump with electrodes. She stands in front of a large flat-panel TV screen that displays a disembodied, flesh-colored arm floating in blue space—a visualization of her phantom. Lock's electrodes pick up commands from Kitts's brain radiating down to her stump, and the virtual arm moves.

ProDigits - The Partial Hand Solution

ProDigits™, short for Prosthetic Digits, are the self-contained fingers that are individually powered and controlled to provide new fingers for partial hand patients.
                                                                                             

Partial Hands Solution

Not having fingers or a thumb to act in opposition to one another makes simple tasks such as holding a fork or a cup difficult and frustrating. Thanks to ProDigits, an expertly built prosthesis rebuilds function and confidence. Each individually powered ProDigit or prosthetic finger provides myoelectric control that has never been possible before. Now patients or users with between 1-5 missing fingers have a solution for what was once a highly debilitating condition.

There are physical criteria that dictate whether ProDigits are appropriate or not ideal candidates have digit absence at transmetacarpal level or higher of one or more fingers, although there are exceptions, and every candidate must be assessed by a qualified clinician before a decision on suitability for a ProDigits prosthesis can be made.

Articulating Digits

New biomechatronic technology will give arm amputees improved control of a prosthetic hand, including a sense of touch. Conventional mechanical prostheses are typically simple grippers. Since these devices do not provide tactile feeling, a user must rely on vision to control their artificial arm.

To address these challenges, Kinea Design LLC developed a novel tactile (haptic) fingertip sensor that enables amputees to explore and interact with their environments. The device provides a broad array of sensory information to the user, including temperature, textures, pressure, friction, and four distinct points of contact.

Additional Kinea Design RP 2009 contributions included:

• a Modular Finger System with one actuated axis of motion: an artificial finger that provides enhanced dexterity and grasping patterns, including an ability to both curl in a natural motion and conform around an object.
• the MPL Palm Module: a stand-alone module that serves as the principal electromechanical interface and enclosure for all the electronic and mechanical hand and wrist-connecting components designed by Kinea Design and other RP 2009 collaborators.
  

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