761 views | Akanimo Sampson | March 28, 2019
In a seeming world first, a Rael-Science post quotes doctors in Sweden as saying they’ve wired a prosthetic hand directly into a woman’s nerves, thus allowing her to move its fingers with her mind and even feel tactile sensations.
Those who know better say the hand is an enormous step up from existing prostheses, which often rely on electrodes placed on the outside of the skin, and it could herald a future in which robotic devices interface seamlessly with our bodies.
Researchers at Chalmers University of Technology and biotech firm Integrum AB created the prosthetic hand as part of DeTOP, an ambitious European research programme on prosthetic limbs.
Surgeons anchored the hand to the woman’s forearm bones using titanium implants. They connected an array of 16 electrodes directly to her nerves and muscles, allowing her to control the hand with her mind — and, according to photos, use it to tie shoelaces and type on a laptop computer.
“The breakthrough of our technology consists on enabling patients to use implanted neuromuscular interfaces to control their prosthesis while perceiving sensations where it matters for them, in their daily life,” Chalmers researcher Ortiz Catalan said in a press release.
Electronics wired straight into a human nervous system allow for mind-bending new ways to interact with technology. A video released by the Swedish researchers even shows the woman using the implant to flex a virtual hand on a computer screen — before the actual physical hand was installed.
For decades, cyborg limbs like those depicted in “Star Wars” or “Neuromancer” seemed relegated to the realm of science fiction. New research shows that they’re already here — just not yet widely available.
A female Swedish patient with hand amputation has become the first recipient of an osseo-neuromuscular implant to control a dexterous hand prosthesis. In a pioneering surgery, titanium implants were placed in the two forearm bones (radius and ulnar), from which electrodes to nerves and muscle were extended to extract signals to control a robotic hand and to provide tactile sensations. This makes it the first clinically viable, dexterous and sentient prosthetic hand usable in real life. The breakthrough is part of the European project DeTOP.
The new implant technology was developed in Sweden by a team lead by Dr. Max Ortiz Catalan at Integrum AB – the company behind the first bone-anchored limb prosthesis using osseointegration – and Chalmers University of Technology. This first-of-its-kind surgery, led by Prof. Rickard Brånemark and Dr. Paolo Sassu, took place at Sahlgrenska University Hospital as part of a larger project funded by the European Commission under Horizon 2020 called DeTOP (GA #687905) (video).
The DeTOP project is coordinated by Prof. Christian Cipriani at the Scuola Superiore Sant’Anna, and also includes Prensilia, the University of Gothenburg, Lund University, University of Essex, CSEM SA, INAIL Prosthetic Center, Universitá Campus Bio-Medico, and the Instituto Ortopedico Rizzoli.
Conventional prosthetic hands rely on electrodes placed over the skin to extract control signals from the underlying stump muscles. These superficial electrodes deliver limited and unreliable signals that only allow control of a couple of gross movements (opening and closing the hand). Richer and more reliable information can be obtained by implanting electrodes in all remaining muscle in the stump instead. Sixteen electrodes were implanted in this first patient in order to achieve more dexterous control of a novel prosthetic hand developed in Italy by the Scuola Superiore Sant’Anna and Prensilia.
Current prosthetic hands have also limited sensory feedback. They do not provide tactile or kinesthetic sensation, so the user can only rely on vision while using the prosthesis. Users cannot tell how strongly an object is grasped, or even when contact has been made. By implanting electrodes in the nerves that used to be connected to the lost biological sensors of the hand, researchers can electrically stimulate these nerves in a similar manner as information conveyed by the biological hand. This results in the patient perceiving sensations originating in the new prosthetic hand, as it is equipped with sensors that drive the stimulation of the nerve to deliver such sensations.
One of the most important aspects of this work is that this is the first technology usable in daily life. This means it is not limited to a research laboratory. The Swedish group – Integrum AB and Chalmers University of Technology – have previously demonstrated that control of a sentient prosthesis in daily life was possible in above-elbow amputees using similar technology (video). This was not possible in below-elbow amputees where there are two smaller bones rather than a single larger one as in the upper arm.
This posed several challenges on the development of the implant system. On the other hand, it also presents an opportunity to achieve a more dexterous control of an artificial replacement. This is because many more muscles are available to extract neural commands in below-elbow amputations.
Bones weaken if they are not used (loaded), as commonly happen after amputation. The patient is following a rehabilitation program to regain the strength in her forearm bones to be able to fully load the prosthetic hand. In parallel, she is also relearning how to control her missing hand using virtual reality (video), and in few weeks, she will be using a prosthetic hand with increasing function and sensations in her daily life (video). Two more patients will be implanted with this new generation of prosthetic hands in the upcoming months, in Italy and Sweden.
Many amputees sometimes feel like the limb they lost is still there. For reasons that aren’t fully understood, these phantom limbs are registered as extant limbs by the brain, and may lead to feelings of clenched muscles, itching, burning, and pain.
A new robotic arm harnesses the phenomenon by hijacking the wayward signals that people’s brains try to send to phantom limbs — and using them to control the prosthesis.
With minimal training, two people outfitted with the new robotic arm were able to use it to grab and drop objects by trying to control their phantom limbs, according to research published Thursday in the journal Frontiers in Bioengineering and Biotechnology.
In a video of one of the experiments, a participant uses the robot arm — connected but not attached to their body — to reach up and grab an object and drop it into a bucket.
The robotic arm reads myoelectric signals — it picks up on nerve impulses through the participants’ skin — to determine what the participant is trying to tell their phantom limb to do. The robot arm rotates its wrist, bends its elbow, and is able to grasp just as a biological arm might, albeit more slowly.
Myoelectric readings, the researchers note in their paper, are not the best way to control robotic limbs. They tend to be slower and clunkier than when prostheses are directly connected to a person’s muscles and nerves. But for the sake of demonstrating that their phantom limb-decoder worker, through-the-skin readings did just fine.
The real key here is that these new prosthetic limbs use signals that the brain is already accustomed to sending — should they someday hit the market, people may be able to skip much of the difficult and cumbersome training that accompanies getting accustomed to most prostheses.