Mind-Controlled Bionic Prosthetics
In the previous article, I introduced you to the advancements that we have seen to date with 3D-printed bionic prosthetics. In spite of significant advancements in reduced cost and functionality, there is still a lot that needs to be optimized in order to validate the technology as something that healthcare practitioners will use as the default standard for replacing lost limbs. Even if all the progress that needs to be made is magically completed, there is still a major gap that needs to be addressed: Will we ever be able to have conscious control over the movement of bionic prosthetics? Moreover, will patients be able to ‘feel’ objects with these prosthetics like they did with their normal limbs?
Yes, I’m talking about the kind of phenomena that you commonly see in science fiction movies. When Luke Skywalker had his hand cut off with a lightsaber during the “Star Wars” saga, it was instantly replaced with a robotic hand that he was able to consciously control with next to no effort. Are we getting there, or are we a long way away from living this reality? Let’s see the progress that science has made to this date in the fields of robotics and neuroscience.
The first name that comes to mind is Össur, an innovative prosthetics company in Iceland that made breakthrough progress when they were able to have two amputees control their prosthetic legs with their own minds. How was this possible? These legs were operated by implanted myoelectric sensors (IMES) that were inserted into the residual muscle tissue of the patient. When the patient wants to move the limb, the entire process begins subconsciously. This results in the release of electrical impulses that are then received by the IMES, which instantly triggers the desired movement through the use of a receiver that has been planted in the prosthetic limb.
This allows for movement that is both intuitive and integrative in nature. Össur claims that their technology can adapt to walking conditions and the walking style of the user in real-time, but this needs to be developed further in order to successfully give the patient complete and unconscious control of their limbs. Preliminary results indicate that the two subjects still have to consciously think about which limb they want to move and how they are going to move it in order for the technology to work.
(Image Source: Shutterstock)
That’s not the only significant development that has arisen in recent years. Researchers at John Hopkins University have developed a prosthetic that allows for independent control of each of its five fingers using nothing but the mind. Electrodes were implanted in the male subject’s brain, followed by instructing the subject to attempt to move individual fingers. It took a long time to do the necessary brain mapping in order to see which parts of the brain lit up when the patient was instructed to think about moving a particular finger. After the prosthetic was re-programmed with this new information, they found that the fingers could be individually controlled with 76% accuracy! The gap remains from the fact that there is significant overlap between parts of the brain that control each finger. This makes sense when you consider that we tend to move multiple fingers at once.
So, what’s next for the development of mind-controlled bionic prosthetics? For starters, there needs to be a shift towards non-invasive methods. It is extremely risk to surgically implant electrodes in a patient’s brain, and there lies the hidden assumption that the brain activity required to activate the muscles from the missing limb are still functioning normally.
Another major advancement that needs to happen is two-way communication between the limb and the user. As mentioned in the introduction, we do not currently have the technology to allow patients to feel a sense of touch with these limbs. This is relevant towards those who suffer from paralysis and would heavily rely on this advancement in order to feel the objects that they are grabbing.
Lastly, there would have to be 100% accuracy in the control of these limbs. If they are going to be truly useful to the patient, there should be no room for any mis-interpreted communication signals between the user and the limb. The experience should feel completely normal to the patient, as if they had normal limbs to begin with.
We have only scratched the surface of the capabilities of mind-controlled bionic prosthetics. Future developments will allow for these limbs to be regularly used in the healthcare and military sectors. Science fiction isn’t too far away from being real life!
By Tom Zakharov
Tom is a Master’s student at McGill University, currently specializing in the field of Experimental Medicine. After graduating from the University of Ottawa as a Summa Cum Laude undergraduate, he is currently investigating novel indicators of chemotherapy toxicity in stage IV lung cancer patients. Tom also has 4+ years of scientific research in academia, government, and the pharmaceutical industry. Tom’s first co-authored paper investigated a novel analytical chemistry method for detecting hydrazine in nuclear power plants at parts-per-billion (ppb) concentrations, which can be viewed here.