What could this summer’s FIFA World Cup have in common with the future of physical rehabilitation? Sports injuries aside, the soccer games themselves won’t have much to do with the advancement of physical therapy, least of all with the herculean achievement that will be on display. Instead, a young man who has been unable to walk since sustaining a spinal cord injury ten years ago will do just that. Using a robotic exoskeleton, Francesco Clark will stand from his wheelchair, walk across the field, and kick the first soccer ball of the tournament.

The planned demonstration has received media attention already, albeit not in an amount commensurate with its magnitude. But that’s not entirely surprising, and I think it has less to do with widespread skepticism as much as generally an insufficient understanding of what exactly we’ll be seeing when we see Francesco walk. My goal in writing this is to help strengthen that understanding, and hopefully put an absolutely groundbreaking achievement into some type of context. I don’t know Miguel Nicolelis, the Duke researcher on the forefront of the Brain-Machine Interface technology that makes this demonstration possible, but I have followed his work since I first saw this video early on in my graduate career. I am by no means an expert, and I will say first of all that I highly recommend Beyond Boundaries to anyone with more than a passing interest in Brain-Machine Interfaces. What I describe below is based upon the current state of the science; it’s always possible that what we see is more advanced although that appears unlikely due to signal processing limitations.

Let’s begin with the basics. Francesco Clark injured his spinal cord diving into a shallow pool, fracturing the C4 vertebra. Generally, individuals with injuries at this level require a ventilator for breathing, and do not have use of their arms or legs. Until recently it was believed that recovery from these injuries was possible only in cases where damage to the cord was incomplete. Based upon his public involvement with research trials involving the use of stem cells, virtual reality systems, and robotic devices, it seems that he couldn’t have sustained a complete spinal cord injury. Nevertheless, he clearly had and still does have substantial physical deficits.

Clark will be wearing a robotic exoskeleton, a kind of electronic suit designed to allow some of the movement he lost when he injured his spinal cord. Unless this is the first you’re hearing of this story, chances are you also heard the words mind-controlled used to describe the device. Since that’s the really critical piece, and by far the least self-explanatory, let’s explore what it means to control something with the mind.

Electroencephalography, or EEG, is the process of recording neuronal activity in the brain. In some ways, the neuron has been viewed as the fundamental unit of brain function since Ramon y Cajal first identified it as a discrete object. More recently, the manner in which neurons and larger brain areas themselves interconnect has been discussed as equally critical for producing thought and movement. Using EEG, researchers will record the activity in the areas of Clark’s brain responsible for development and execution of movement tasks. Those areas of the brain are undamaged, but their signals aren’t able to reach the muscles in the arms or legs because that information travels down the spinal cord.

With the recording electrodes in place on Clark’s scalp, he will start to think about standing up. During his practice with the device, it’s more than likely that he was instructed to do exactly this dozens of times, and that the average of the recorded neuronal activity was used to calibrate the machine. The reason for this calibration is that electrodes located on the surface of the scalp not only have the skin, skull and cerebrospinal fluid to contend with, but also billions of adjacent neurons firing away to perform tasks other than standing and walking. The alternative to this method of recording is more precise, but involves opening a hole in the skull, which is naturally less desirable to the user. Additionally, it’s critical to find the right balance between very broad and very narrow recording. Because we now understand that the connections between neurons are as important as the neurons themselves, we know not to compromise the harmony of the symphony by focusing too closely on just a handful of the instruments, to borrow an analogy.

In a way, calibration of the device is similar to identifying differences between two pictures.

After this signal in Clark’s brain is detected, it will travel from the electrodes on his scalp to a computer within the exoskeleton device. There it will be decoded into a digital signal that the device can use. This processing would be impossible without the meticulous calibration described previously. In a way, the calibration process is similar to the childhood activity of finding differences between two similar pictures; when the device’s computer calculates that the recorded signal is similar to the signal that has been programmed to mean “intention to stand up” or “intention to walk,” the machine will begin to facilitate that movement. Similarly to what would happen along the spinal cord and ultimately reaching the muscles of the legs in an uninjured person, that digital signal will instruct the robotic legs to move at the hips, knees and ankles, allowing Clark to stand from his wheelchair.

If that seems overwhelming, step back for a moment from the exoskeleton device. Imagine a light in front of you that can be switched on or off. Now, consider that the activity in your brain when you think of the command “turn the light on,” is different from the activity within your brain when you instead think “turn the light off.” Next, imagine that you put on a special kind of hat that can record your brain’s activity. That hat is connected to a switch that turns the light on or off. You put the hat on and a scientist instructs you to think of turning the light on. You do so, and your brain activity is recorded. This information is then used to calibrate the hat, so that next time you have the same thought, the hat can simply compare your brain activity with that original recording; if the activity is the same or very similar, the hat knows that you are thinking “turn the light on.”

In his book, Nicolelis describes a future without a need for steering wheels to drive cars or keyboards to type into computers based on this type of technology, and it’s difficult to disagree with him. He also offers a really excellent quote in a TED talk: “Impossible is just the possible that someone has not put enough effort to make come true.” Probably there are lots of business people and other professionals who have similar quotes handy, but Nicolelis is absolutely living that message with the work he does. Whether or not this technology becomes widespread in the near future, he will succeed in demonstrating that we’re at a point where concepts and inventions previously relegated to sketches and notebooks can become very real, and make significant impact for those in greatest need.

As always, thank you for reading. If you enjoyed this please feel free to share it, and your questions or comments are always welcome.