When Luke Skywalker has his hand cut off in The Empire Strikes Back, he simply has it replaced with a mechanical one that looks, moves, and feels like a real hand. Now, whether you have lost your limb to a lightsaber or a disease, there is a real world equivalent to Luke's bionic fist: the Smart Hand. Developed by EU researchers, the Smart Hand is a complex prosthesis with four motors and forty sensors designed to provide realistic motion and sense to the user. That's right, Smart Hand is the first device of its kind to send signals back to the wearer, allowing them to feel what they touch. The first time I saw this, it completely blew my mind. Take a look at the video from BBC News after the break.
Generally when we've discussed haptics (sense of touch interfaces), it has been in relation to remote access or telepresence robots. At once, the use of haptics in prostheses is both more intuitive and more intimate. The ability to create feeling extensions of one's body has implications beyond the (not so) simple creation of life-like limbs. We could see bionic replacements that augment human physicality beyond the normal limits. These replacements, if accompanied by an advanced sense of touch, would have all the benefits of a natural part of your body and yet function better. Full body replacement, or rather body displacement, is the stuff of science fiction movies like Surrogates. Yet if we find a way to perfectly translate mechanical sensation to human sensation, there would be little technological obstruction to extending our consciousness outside our biological bodies.
Phantom limb syndrome is the sensation amputees have that their missing body part is still there. The brain has remained open to receiving input from those nerves although they were cut off long ago. Likewise, impulses from the brain to control the missing limb still travel down the neurons towards the sight of amputation. Scientists can use electronic sensors to pick up the control signals and relay them to a mechanical device. We've seen this technology used in the HAL exoskeleton from Cyberdyne, and in the i-Limb prostheses. Smart Hand is unique because it also takes advantage of those phantom limb pathways still being open. Doctors connect the sensors in the hand to the nerves in the stump of the arm. Now, patients can feel as well as control an artificial limb.
The Old You...Maybe Better?
The goal of the Smart Hand project is to create a replacement limb that is as near to identical to the lost one as possible. This means creating a prosthesis that functions and relays sensory input like a normal biological hand. In both objectives, the Smart Hand is far from ultimate success. Four motors, though providing an impressive range of motion, do not have the full degrees of freedom, nor the variation in applied strength that a human hand has. Likewise, it is amazing that the forty sensors can communicate with the human brain at all, but they do not provide nearly as much sensation as the millions of nerves in your biological hand. Yet, as mentioned in the video, the current Smart Hand prototype represents more than ten years of dedicated work.
I only point out the current limitations of Smart Hand to better highlight its enormous potential. Robin af Ekenstam (the patient in the video) can pick up objects, and can feel the fingertips of the prosthesis even at this stage of development. It is clear from his involvement in this project that this level of capability is well worth the time and effort involved. In other words, an imperfect Smart Hand is still a very desirable hand, and can perform remarkable tasks. What happens as Smart Hand gets even better?
The number of scientists dedicated to answering that question is rather astounding. In the Smart Hand project we see the work primarily of Lund University in Sweden and the Scuola Superiore Sant'Anna in Italy, but contributors include researchers in Denmark, Israel, Ireland, and Iceland. We've seen many other successful prosthetic companies including i-Limb, DEKA, and Ossur. A good number of robotic hand projects work in parallel with prostheses research, including the gentle SDM robotic hand we recently discussed. On the frontier of nerve-machine connectivity are projects like Braingate, which directly connect motor nerves to computers.
Clearly, there is an abundance of resources being directed at all angles of this research coming from many different regions and fields of expertise. When we consider these resources we can rest assured that although it has taken ten years to give us the current version of Smart Hand, it will take much less time to make large improvements upon the technology. Whether or not those improvements occur in this project, or another, it is likely that prosthetic work could see some sort of exponential growth in the upcoming years.
Which means that sooner than we may think, those suffering from missing limbs may be able to heal themselves to a degree beyond their expectation. In the next several years, perhaps decades, prostheses may come to match our natural bodies in most meaningful ways.
Beyond that, of course, sits the realm of abject speculation, but if artificial limbs will one day match the human ones, there's no reason they couldn't be further improved. We would then see bionic limbs, or perhaps entirely bionic bodies, which exceed human limitations. Could these mechanical bodies be accepted as authentically human? Already the Olympics have decided that some athletes with prostheses have an unfair advantage and are ineligible to compete. In the years to come we will see how society at large reacts when "good enough" becomes "good as new" and finally "better than ever".
[photo credit: Smart Hand Project]