New update on scES study | Kate Willette

Posted by Reeve Staff in Research News on October 26, 2017 # Research

We have some news.

A lot of you already know about spinal cord epidural stimulation (scES), both from Sam Maddox’s reports on this blog and from the regular media. Remember? ES involves planting an array of electrodes into the epidural space in the lumbar area of the cord. By way of a wireless control, those electrodes allow a researcher to send a pulse on command into the lower spine. The idea of scES isn’t to stimulate a muscle or two, but to activate whole networks of neurons that injury to the spinal cord has left without useful input. In theory, delivering the correct scES jolt in combination with calibrated standing and stepping training might just create the potential for motor recovery.

Since Susan Harkema’s team in Louisville, KY first gave us the very promising results from their scES work with Rob Summers several years ago, the procedure has been repeated, replicated, tested, and refined. Bit by bit, scientists are trying to zero in on the right way to combine scES and activity-based training, and today’s paper in Scientific Reports is a serious step forward on that path.

The hardcore among you will want to read it yourselves, but for the rest, I’m offering this user-friendly summary.

After their success with Rob, the Harkema lab put stimulators into three more young men with chronic, motor-complete injuries. (Sam wrote up the results here.) One of those young men — Drew Meas — volunteered to keep going with the research; the new paper is about what happened to him in round two. When he was 28 years old, Drew got a C7 injury in a motorcycle crash. He spent the next three months in the hospital, a stay that included about seven weeks on the inpatient rehab floor. After he left the hospital, he signed up for locomotor training sessions that went on once or twice a week for the next year and a half.

Nothing. No return.

At 21 months post, he abandoned the locomotor plan and moved on with his life. More than two years went by, and then he heard about the Louisville trial. Drew raised his hand for that, and was accepted. He went through the protocol: first more locomotor training, then the surgery, then months of standing training followed by more months of stepping in the harness. After all that and with the stimulator on, Drew could stand independently. He could also flex his hip and extend his knee while lying down, as long as the stimulator was on.

Drew, at this point, was about five years post injury. He’d been actively trying to recover for more than half that time, and he wasn’t done. They sent him home with a custom-made standing frame; the ES was still in his lower back, of course, and he used it daily to get on his feet in the frame. After a year of this, he said yes to a chance to try something different in the lab.

This time they tried having him stand for an hour, rest, then step for an hour. The next day it was the opposite: first step, then rest, then stand. One of the problems from the original training was that the guys lost ground on their ability to stand after they’d moved on to stepping. Maybe if both were trained at the same time, that could be avoided … this is the sort of question that can only be answered, slowly and painfully, by trial and error.

The back-and-forth, step/stand training went on, five days a week, for another three months, and was followed by another 14 months of home-based standing. Finally, it was back to the lab once more for another hundred sessions of step training. Every day, Drew would go to the lab and focus on stepping, then go home and use his frame to stand.

What happened?

We observed substantial recovery of volitional lower limb motor control and independent standing ability without using scES in an individual with chronic, motor complete SCI …

Drew could flex that hip and extend that knee while lying down with the stimulator turned off. He could stand up by himself with the stimulator turned off. This matters because it means that somewhere in this mix of stimulating and training, there was a reorganization of the cells in Drew’s spinal cord – and if that can happen once, a little, it can happen again, a lot.

That’s news.