New Device Helps People With Paralysis Walk Again

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Spinal cord injuries are notoriously difficult to treat, especially for those who have been paralyzed for several years. But now researchers have developed a new implant that is able to reverse paralysis in patients with complete spinal cord injuries. It uses specially-designed electrodes, which can bring the brain back into communication with the patient’s lower body.

The findings were published in the journal Nature Medicine. Joining me now to talk more about this exciting new development are the study’s co-authors, Jocelyne Bloch, neurosurgeon at Lausanne University Hospital, and Gregoire Courtine, professor of neuroscience at the Swiss Federal Institute of Technology, based in Lausanne, Switzerland. Welcome to Science Friday.

GREGOIRE COURTINE: Thank you very much.

JOCELYNE BLOCH: Thank you.

IRA FLATOW: Dr. Bloch, tell me, how does this implant work?

JOCELYNE BLOCH: So I implant electrodes, and these electrodes are located just upon the spinal cord. And they are linked to a neurostimulator. That is a little computer like a pacemaker that is located in the region of the abdomen, in the belly, and connected to the electrodes.

So how does it work? So we put programs on this little computer, and we studied how to mimic the activation of the spinal cord in reality and physiologically. And we do exactly the same with the electricity. So it means that when you walk, you generally flex your hip, and then do extension and flexions on the right, on the left. And we activate the different parts of the spinal cord that are responsible for this or this function.

IRA FLATOW: And once the stimulation is started, the patient is able to control his legs at will.

JOCELYNE BLOCH: As soon as we start understanding what to stimulate– so it takes a few hours to understand the cartography, the mapping, of the spinal cord– then the patient stands up, and we activate the intended program to walk. And immediately, the patient can step.

GREGOIRE COURTINE: And to rebound on this question, you know, the majority of spinal cord injuries, despite defined as clinically complete, are actually anatomically incomplete. And what we observe, surprisingly, is that when we turn on the stimulation, the residual pathways coming from the brain that are normally silent become functional. So the stimulation will boost the residual coming from the brain and enable the modulation of the activity, which is induced by the stimulation, as Jocelyne pointed out.

IRA FLATOW: Why do you think that your stimulation works while others in the past have not been able to do this?

GREGOIRE COURTINE: Many groups in the past have stimulated in the spinal cord to reactivate the motor circuits involving the control of leg muscles and happened to have many successes, so it is not that it did not work. What we achieve here is the development of the first purpose-built technology to activate the human spinal cord. The consequence is that it is more precise. It’s more effective.

And also, as Jocelyne pointed out, it is not a continuous stimulation as the other group applied before, but it’s actually modulating. So it’s a pattern stimulation that aims to reproduce a natural activation of the spinal cord, as the brain would do naturally if there would be no spinal cord injury. And this is really the effective impact of the stimulation.

IRA FLATOW: And the patient is able to basically speak into a portable device that turns it on, and then the patient can move.

JOCELYNE BLOCH: Exactly. So we have different programs that we adjust depending on the activity that is chosen by the patient. So for example, walking, and then the patient can select the walking program, and he steps. And then he can select another cycling program, and we’ll have a designated program for cycling. And he can have the swimming program or the standing program. And each of them have a different program, yes, that is voice-controlled with a watch.

IRA FLATOW: You know, I was watching a video of your patient, and the patient was saying, hey, look, I’m going to show you something special. And the video showed that he was able to wiggle his toes without stimulation, Dr. Courtine.

GREGOIRE COURTINE: Yeah, this was an amazing moment that we had not anticipated. Originally, the stimulation was meant to reactivate the spinal cord and restore movement. But when you combine this stimulation with training, because the stimulation enables this high level of activity, progressively, nerve fibers start growing again.

And what we observe– the patient you mentioned was David, a tetraplegic for eight years, and after three months of training, was able to wriggle his toe. Two months later, full leg extension against the direction of gravity. After eight months, he could step independently without support, without even stimulation.

IRA FLATOW: And so this was something that was surprising to you, too.

JOCELYNE BLOCH: Yeah, that was very surprising, especially that David, who was in a chronic state. So it means that he had already trained the max he could have done, and he had reached a plateau. So it was unexpected for me to see that he could improve a second time. But maybe just to precise, also, because we’ve now implanted nine patients, and David was belonging to the group of patients who had an incomplete injury, meaning that there were still a bit of functioning path. He could still move a little bit of one leg and had feeling on his legs.

So the last three patients had a complete lesion, meaning that there was nothing. They could not move. They had no sensations. And those ones, those three, even if they could immediately step with the stimulation, we did not observe such a good recovery without stimulation, even with training.

GREGOIRE COURTINE: Yeah.

IRA FLATOW: But those patients were still able to walk with the stimulation?

GREGOIRE COURTINE: Oh, of course.

JOCELYNE BLOCH: Oh, yes.

GREGOIRE COURTINE: It is very different that you have a recovery without stimulation. This is the ultimate grail, our intimate goal. And as Jocelyne pointed out, these are people with chronic spinal cord injury, up to 13 years after the occurrence of the accident. So imagine when you apply this type of intervention a few weeks after the occurrence of the accident, when there is a huge potential for recovery. And that’s one of the objectives of a future study we are preparing with Jocelyne.

IRA FLATOW: So the objective, then, is to be able to get all of the patients to be able to walk without stimulation.

JOCELYNE BLOCH: That would be the dream, but the objective– we are happy if people can walk. And I think with or without stimulation, I think only those who have an incomplete spinal cord injury can reach this objective. Those who have a complete spinal cord injury will not be able to walk without stimulation, at least for now.

IRA FLATOW: And how long does it take for patients to be up and walking again after receiving the implant?

GREGOIRE COURTINE: With our new technology, purpose-built with this suite of software with artificial intelligence [? on market, ?] within one day, they stand, they step. Of course, poor quality, a lot of body weight support. But immediately, we can re-engage the spinal cord, and they can train intensively. And depends from patient to patient, you know, but after about three to four months of training, you would observe full weight-bearing standing and independent stepping without any body weight support. More or less this is the timeline we have seen so far.

IRA FLATOW: And when might something like this be available to everybody, or more widely?

JOCELYNE BLOCH: So already a few years ago, with Gregoire, when we were starting these clinical trials, we realized that it was quite a lot of energy for us to spend a lot of time with these patients with this non-purpose stimulation system that was normally done for pain, and that it would take a huge amount of energy to make it work for more than a few patients. So we knew at this time already that in order to have a treatment available for everyone, we would need to have a company working for us, a company dedicated to build these kind of devices that are easier to use, that are designed to be done for that, and that can also be reimbursed by the insurances.

That’s why we currently work with ONWARD Medical. It’s now a company that is working on making devices that will be for everyone. And that’s what we aim. So next step is to have a larger clinical study with more patients. And we hope that in a few years, we’ll have a treatment for everyone.

GREGOIRE COURTINE: And just to complement this, ONWARD obtained the device breakthrough designation from the FDA. So there will be a facilitated path for ONWARD to have clinical trials in the US with validation of the technology. So the first aim is really to go to the United States with this therapy as early as a year from now.

IRA FLATOW: Are there patients for whom this device will not work?

JOCELYNE BLOCH: The place where I implant the electrodes is the place that should be intact, the 6 last centimeters of the spinal cord. So the people who have a lesion very, very low located are, for now, not good candidates for this therapy. But it may change. So the people who have other types of lesions that are, for example, very severe and very high, the ones who cannot at all move the whole body, I mean, we don’t think that the priority is walking. And there are certainly other functions that they would like to gain before that, like moving the hand, or maybe we can also take care of blood pressure problems that are very often happening when you have a very high spinal cord lesion.

GREGOIRE COURTINE: If I can complement, the key for now is for us to empower people with spinal cord injury with this technology to improve all the neurological function that matters to them. And there’s still a long way to go, but this is really our goal, to bring this technology to the people in need.

IRA FLATOW: So this is a proof of concept.

GREGOIRE COURTINE: Well, it’s clearly an academic proof of concept. But since we are collaborating very tightly with ONWARD that has been developing the purpose-built technology for this very application, we are past the proof of concept. It is really in the implementation of an actual therapy.

IRA FLATOW: Do you think, then, that this discovery and the way you use the stimulation opens the door to other researchers that might think, hey, I’m going to see if I can try to do what they’re doing, and maybe speed up the process for everyone?

GREGOIRE COURTINE: We would love that, indeed. We have already started a lot of conversation with research groups in the United States in order to have collaboration. You know, at this moment, we really need to expand and show that other groups can apply the same type of therapy, can improve it. And we need to work together in order to make the therapy available for everyone.

IRA FLATOW: Dr. Courtine, Dr. Bloch, thank you very, very much for taking time to talk with us. And good luck to you.

GREGOIRE COURTINE: It was pleasure. Thank you so much.

JOCELYNE BLOCH: Thank you very much.

IRA FLATOW: And that’s about all the time we have. Jocelyne Bloch, neurosurgeon at Lausanne University Hospital, and Gregoire Courtine, professor of neuroscience at the Swiss Federal Institute of Technology, based in Lausanne, Switzerland. And there’s a great video of David and Michelle, two patients in this study, walking with the help of this stimulation device. And you can see it on our website, sciencefriday.com/paralysis.

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