The nerds among us, including myself, grew up on science fiction movies such as Star Wars. We reveled in moments that were so far beyond what we could imagine – aliens, spacecraft and Jedi being some prominent examples. But we also took comfort in moments that we could relate to – the heartache of star-crossed lovers, the thrill of danger, and the journey of a hero. And if the hero got knocked down, there was always amazing technology that could get them back up. Bacta tanks were the answer to freezing in the cold of Hoth, R2-D2 could be patched up, and if you lost an arm, an animatronic replacement was just around the corner.
Modern medicine for amputees, however, is much closer to a peg-legged Captain Hooke than ‘a long time ago, in a galaxy far, far away.’ However, advances in medicine mean that a far greater number of people are able to survive injuries that the used to die from, including amputations of limbs. Along with the fact that these people are also going to be living far longer, we now live in a society where we try to get those who are disabled to live the most normal lives that they can. The problem is that modern limbs are very limited. Only recently have we been able to solve issues so that people have control of fine motor skills via the central nervous system, along with new increases in mobility and animatronics.
The main barrier that stands between the current world and Star Wars is the sense of touch. All false limbs currently are made without any sense in the appendages. This means that, even though you can pick something up, you can’t feel that you have done it. That doesn’t sound like so much of a problem, does it? Think again!
The reality is that our sense of touch is used so often we hardly think about it. We control the amount of force that we use to type on keyboards, open a door, or cradle a laughing child, by noting our grip strength and applied force. When you pick up a smooth metal water bottle, you have to apply a significantly greater amount of force to maintain your grip than you would have to if you were holding an orange. However, we can feel that we can use that force on the bottle without damaging it, while such force on an orange would crush it, through our sense of touch.
Unfortunately, amputees cannot benefit from this sense of touch. This makes their lives much more complicated. Given the fact that the control of their new limbs is far from perfect, and that the difference in force needed in the above example is significant and can result in damage, they must act with care every moment of their lives. Some things, such as holding a young child, can sometimes simply be beyond them.
Enter the combined Swiss-Italian research team led by neuro-engineer Silvestro Micera of Switzerland's Ecole Polytechnique Federale de Lausanne. Previous pilot programs in Europe and the US have been able to give patients who are test-driving the prototypes a sense of touch. However, this new research, Restoring Natural Sensory Feedback in Real-Time Bidirectional Hand Prostheses, published in Science Translational Medicine, takes technology even further. As the Sydney Morning Herald reported, the test subject of the new technology was “not only could tell differences in the shape and hardness of objects, he also could quickly react and adjust his grip.” This ability to react and adjust is key, allowing amputees to use their new limbs as if they were their original appendages. Micera noted that, even with this primitive prototype, "[The test subject] was able to use this information immediately in a quite sophisticated way."
Key to this new technology is the implanting of nerve sensors into the nerve endings in the amputated limbs. This innovative adaptation allows for direct motor control and sensory feedback. Scientific innovation of this sort is the result of not only the individual scientists and engineers working on the project and experimenting with different approaches, but also building upon the innovations of generations of scientists that have come before them. The creativity has to be seen, as Sterberg et al argue, not as the invention of a new thing, but rather as the improvement and application of existing things in a new way.
Dennis Sorensen of Denmark, the test subject of the new technology, raved about the results. "It was just amazing," he said. "It was the closest I have had to feeling like a normal hand." Sorensen is also very excited about moving past the primitive nature of current prosthetics. "You always have to look and see what's going on, so that's what is so much different from this new hand that I tried," said Sorensen, alluding to difficulties including dropped plates and crushed objects.
Noted scientists praised the joint venture as “an important step.” Biomedical engineer Dustin Tyler, leader of a similar research project in Ohio, commended the work, noting that “it is really putting the brain back in control of the system.” University of Pittsburgh neurobiologist Andrew Schwartz noted the simplicity of the project, adding that "It shows with a few sensors and some pretty elementary technology, they can recover a fair amount of functionality."
While mass production, or even a portable version, of this technology is still years away from development, the clear advance in this technology is worthy of commendation. The best thing is that, for the millions of amputees around the world, this means that soon they will be able to live their lives more like those with healthy limbs. For the nerds among us, it’s even more exciting – the reality is that Star Wars is that much closer.