In a recent study, researchers at UC Irvine helped a paralyzed man walk across a room for the first time in years by harnessing his own brain waves.
Like many scientists searching for volunteers willing to take part in spinal cord injury research, they reached out to a San Diego County company where people stay active by getting out of their wheelchairs.
The research subject at the center of this particular study was Adam Fritz. In 2008, a motorcycle accident left him paralyzed at the age of 21.
Fritz recalls commuting home during L.A. rush hour when, "a table had fallen off the back of a truck. It was on the freeway. And like typical Southern California traffic, everything was packed. I had nowhere really to go," he said.
The connection between Fritz's brain and his legs was severed.
But recently, during brief sessions in a UC Irvine lab, that connection was restored. Scientists linked Fritz's brain and legs by placing electrodes on his head and muscle stimulators behind his knees. That empowered Fritz to take steps again using his own thoughts.
"It's absolute concentration on just one thing," Fritz said. "Normally, you don't think about walking. You just do it. But for this, each step has to be deliberate and very focused."
The researchers recorded videos throughout their study. In one of them, you can see Fritz strapped into a safety harness and steadying himself on a walker.
His movements are a bit wobbly. But essentially, what you see is Fritz putting one foot in front of the other, walking across a room using his own brain power.
"What this proves, basically, is that the brain signals that underly walking are still preserved years after paralysis," said Zoran Nenadic, a UC Irvine scientist who co-led the study with An Do.
Those brain signals "can potentially be harnessed using technological tools. And they could potentially be converted into something that's useful," Nenadic said.
Nenadic said he and his colleagues achieved a breakthrough, because they enabled Fritz to walk without relying on any robotic components or exoskeleton parts to move his legs for him. They helped him use his own brain power to stimulate his own muscles.
Before they let Fritz try to walk, they made him go through a few months of brain training.
"The goal of the game is to walk forward," said Nenadic, demonstrating a simple video game Fritz learned to play using an EEG cap instead of a game controller.
The researchers needed someone with enough mental stamina to sit through the early, tedious parts of the study.
They also needed someone physically capable of supporting their own weight without breaking a bone; someone who wouldn't faint right after standing up. Nenadic said Fritz was a good fit.
"I think one of the reasons why he was able to take this to the next level is he maintains a fairly healthy lifestyle," Nenadic said. "He keeps himself physically engaged. He does get out of the chair once in awhile."
Fritz stays active by going three times a week to Project Walk, a kind of specialty gym for people with spinal cord injuries.
The company is based in Carlsbad. Fritz used to drive over an hour each way to get to their primary location. Project Walk has since expanded, and Fritz now frequents a gym closer to home.
Project Walk isn't covered by insurance — an hour at one of their gyms can costs around $100 — but it gives people a chance to go above and beyond typical therapy. Here, clients use weights and treadmills to push the limits of their motor function.
"All the exercises that our clients do are out of their wheelchair," said Project Walk's chief operating officer Brian Malkinson. "It's load-bearing, trying to promote bone density, bone growth and general, overall health."
Malkinson said scientists often reach out to Project Walk when they need motivated volunteers who can handle the physical demands of their studies. That's how the UC Irvine team connected with Adam Fritz.
"The criteria is very specific, as far as type of injury and ability," Malkinson said. "I know Adam fit that mold because of his experience with us."
Fritz said his time at UC Irvine gave him a glimpse of the future. He knows the technology isn't ready for the real world yet. The gear is currently too clunky, and the brain signal processing needs some refinement.
Researchers want to package the whole system into a small implant that would go inside a patient's skull, but they admit that will take years, if not decades, of work.
Still, Fritz holds out hope that a streamlined version could be ready for daily use in his lifetime.
"I'm not going to walk right now, but I hope some day I will," he said. "You can bring back that hope that you had when you were first in the hospital. Because it's starting. It's going on now."
So far, Fritz is the only person who's used this system to walk. He wants to see other people with spinal cord injuries volunteer to move the science forward by taking first steps of their own.
