Cyborg Possibilities – The Arms and Legs (Part Three)
This article doesn’t need any of the special categories or explanations – the two classifications are pretty self explanatory. Let’s jump right in.
(We’ve come a pretty long way from this.)
The most recent advancements in bionic arms seem to be included in the BeBionic prosthetic arms. This arm can detect signals in the nerves that exist in whatever amount of the arm remains and then uses those signals to drive the prosthetic’s functions. Essentially, operation ought to work much like the user’s original arm did: The person thinks about moving their arm in a certain way and the arm responds.
Despite looking cooler, the BeBionic hand is still a ways away from a human hand. Yet, the improvements are impressive. Grip strength has improved from about 17 pounds to about 31. It can hold about 100 pounds of weight, up from about 70. It also comes in a range of designs. The hand isn’t exorbitantly expensive, but at $25,000 to $35,000 it isn’t exactly cheap either. At that price range, concerns that future human enhancement technology will be a possibility only for the well to do seem likely.
Fortunately, there are alternatives. For instance, two designers recently created a prosthetic hand for an extremely frugal $150. The hand is an excellent example of multiple new technologies converging, as much of the prosthetic is 3-D printed. This particular hand is impressive for the low cost, but there are downsides as well. For instance, this hand is operated via pulley system. Instead of electrical signal sensors powering the hand, regular old nylon rope attaches to the fingers of the prosthetic hand and a ripcord connects to what remains of the biological hand that attaches to the arm. When the ripcord is pulled, the fingers close. It does restore functionality, and it’s most certainly better than nothing, but it’s not exactly elegant. It also doesn’t seem very useful for someone entirely without their biological hand. Yet, for the boy who it was custom made for, the results are pretty impressive.
A few things are worth remembering, however. First, this is an extremely inexpensive prosthetic. There’s a lot of wiggle room between $150 and $35,000, and the sweet spot between price and performance may well lie a few thousand dollars to the right (though still within the range of many not-rich people.) Second, this is an early design, and it’s opensource, which means we can likely expect better functionality soon. Third, technology is advancing all the time, so things that are prohibitively expensive now will become cheaper in a year or two. The amount of functionality that $150 can buy will continue to improve.
Of course, that third point means that the top end technology will continue to improve too. So, assuming one is fortunate enough to be able to afford the latest and greatest prosthetic, what might that look like? Enhanced dexterity is one of the most important improvements that can be made, and some progress is being made on that front. Instead of detecting muscle movements, it would be very helpful if the limb could just read the wearer’s mind and perform accordingly. Although it is not yet ready for a prosthetic device, a team of MIT and Massachusetts General Hospital researchers have created a device that allows monkeys to move a cursor on screen with their thoughts. See below for similar technology in prosthetic legs.
The robot Rex, featured in Part Two, also has prosthetic hands that have individually controlled fingers.
Ultimately, prosthetic limbs shouldn’t just replicate biological limb functionality, they should improve upon it. Two students of Singularity University – the joint Kurzweil / Diamandis tech university – have created a glove that even folks who still have both their hands can use. This glove allows users to sense vibrations, temperature and sound. It also has an accelerometer and a buzzer for important notifications. The next version will be able to detect ultrasonic waves, potentially allowing users to detect, say, breast cancer lumps and heart abnormalities. It’s easy to imagine the technology in this glove transferred into a prosthetic hand, and for additional functionality to be included. Why not equip your bionic hand with a screen, connect it to the internet, and insert a light source? Why not integrate cellular phone technology, or GPS? The possibilities are endless.
Much of the 2012 news about prosthetic legs focused on Olympic athlete Oscar Pistorius. Rightfully so, I’d say – it’s pretty amazing that a person without biological legs can run within a few seconds of the fastest human beings on the planet. Perhaps even more impressive is that Pistorius’ legs aren’t particularly advanced. Certainly they’re state of the art in terms of lightweight running limbs, but there are no electronics in his legs. It was Oscar’s performance that was amazing, not the technology in his legs.
For hi-tech limbs, we can look at the leg developed by the Centre of Bionic Medicine at the Rehabilitation Institute of Chicago. Like the bionic arms above, this leg responds to muscle signals. Unlike many other prosthetic limbs, this one can move at both the knee and the ankle. An on-board computer uses an algorithm that adapts to each individual user. As the algorithm gets better, the legs is better able to predict what the user is trying to do and assist them in that task.
Using this leg, Zac Vawter was able to kick a ball, walk around, and climb stairs (a task more difficult than it sounds for above the knee amputees.) Indeed, Zac was able to climb stairs so well that he took the stairs all the way to the top of the 103 floor Sears Tower in Chicago.
A similar leg was installed on the aforementioned Rex. The Genium leg is controlled by three microprocessors, has four sensors to sense its location in three dimensions along with its speed, and allows the users to “walk backwards, shuffle step, stop short, pivot on their prosthetic leg and perform a wide range of common movements naturally without concentrating.” The powered knee allows users to stand and climb stairs – something traditionally very difficult for above the knee amputees – and lasts for five days.
Other prosthetic legs seem to be at a similar stage of development.
Not everyone needs a prosthetic leg, however. Sometimes the bionic legs we have just don’t work properly. For some of these problems the Hanger WalkAide may be helpful. For patients who suffer from “foot drop” (an inability to lift one’s leg), the WalkAide provides electrical signals to the nerve responsible for lifting the foot at the correct times. Essentially, the WalkAide combines the predictive technology of a bionic leg with an easy to wear device that can be attached to a biological limb.
Finally, as with prosthetic arms, inexpensive versions of prosthetic legs exist. Jaipurfoot.org provides inexpensive foot, below knee, and above knee leg replacements to people around the world. As with cheaper prosthetic arms, the technology in cheaper prosthetic legs does not (and is not supposed to) match that of the more expensive versions. The Jaipur legs and feet have no microprocessors, no gyroscopes, and no batteries lasting for days. Yet, for folks who cannot afford tens of thousands of dollars for a state of the art prosthetic limb, the ability to walk again at a reasonable price is vastly more important than whether or not their leg is able to anticipate their next step.
Oh yes, that goes for cats, too.