For the first time since the explosion, William Gadsby thought about bending his knee, and it happened.
His keys were banging against his hip so he reached down and dropped them on the floor. But he had lost his knee in 2007 during his second deployment in Iraq, when his leg had to be amputated following an explosion.
He was using a brain computer interface, or BCI, that — through circular surface electrodes stuck to his head — responded to his reflexive thought to bend his knee and unlocked the simple mechanism on the prosthesis he was wearing.
“It’s hard to explain how great something is that we all take for granted,” he said of his experience. “BCI is one of those things that give you a reason to wake up the next day.”
Researchers with Hunter Holmes McGuire VA Medical Center in Richmond are working with the BCI technology to allow veterans who depend on prostheses to move naturally.
But that’s only the beginning, they predict. Eventually, anyone depending on technology to move might be able to control it seamlessly.
Veterans like Luke Sprotte, who has a spinal cord injury, walk because of a system called ReWalk, a robotic exoskeleton, thanks to a VA study. ReWalk provides him a great deal of freedom, but using it isn’t always intuitive and takes a lot of practice.
Maybe eventually, Sprotte will be able to use BCI to control the exoskeleton, the researchers hope — he could think about walking forward, and the technology would take him there.
“The whole trick is to isolate one thought out of thousands and thousands and thousands of thoughts ... and then build a reliable system that can be used every single time,” said Dr. Douglas Murphy, a VA physician working on the BCI study.
Building the BCI system was the first phase of the study, and now the second phase involves a 5-year grant of nearly $1 million awarded by the National Science Foundation to make the technology user friendly.
The goal at the end of the five years is to create something that could actually be used by those who need it, from the more than 2 million people in the U.S. who have lost limbs to the 27,000 veterans with spinal cord injuries.
Murphy and a team of researchers and prosthetists — including John Fox, chief of McGuire’s orthotic and prosthetic lab, William Lovegreen with the Department of Veterans Affairs and Dr. Ou Bai with Florida International University — are working to make the technology easier to use.
When they sit down and talk , Fox, Murphy and Lovegreen quickly begin referring to the game-changing ways the BCI technology could alter experiences for anyone who has lost a limb or depends on technology to move.
“It’s going to be phenomenal,” Lovegreen said. “You can ask any amputee, they’re always conscious of their prosthesis, they’re always conscious of where they’re putting their foot ... People with able bodies, we take that for granted.”
The patient wears surface electrodes on his or her head that pick up brain waves, which are then processed by a device about the size of a pager before being transmitted to the prosthesis.
The electrodes sit over the motor cortex and pick up the thoughts that would move an amputated leg, Murphy explained.
The hardware is constantly changing, he added. It started out more cumbersome with the patient wearing a backpack that held the technology to process the brain waves, but has since gotten progressively smaller.
The researchers began their work with a simple prosthesis with a locking knee, but they see the technology becoming increasingly advanced.
“Just like every year there’s a new smartphone, technology and prosthesis are moving that way,” Lovegreen said.
“Eventually,” Fox said, “the electrodes will be down to a pair of glasses they can wear.”
After a training accident in January 2009 left him with a spinal cord injury, Sprotte could stand with the help of a few devices, like a standing chair he has in his North Carolina home, but he couldn’t walk.
During a recent visit at McGuire, Sprotte was working on mastering the ReWalk system to walk up and down ramps. It wasn’t easy because when the system feels the ramp, it senses a barrier and stops and Sprotte must adjust his balance so it starts moving again.
“The first time walking, it was pretty unique, kind of like you’re floating on something that you can’t feel that’s carrying you around,” Sprotte said. “I had to learn to just trust that this was going to do what it was supposed to do.”
Allowing veterans like Sprotte to walk carries a host of health benefits, the head of the ReWalk study, Dr. Ashraf Gorgey, said.
It builds up muscles that otherwise aren’t used, helps improve the digestive system and, Gorgey added, the VA is hoping to show that being able to stand and walk regularly also improves quality of life.
“How is a device like this going to make someone be able to be independent in society?” said Gorgey, who is also on the BCI grant research team.
“It can reflect back on (the patient) in a positive way and helps them gain the benefits by feeling that they are independent: I can do this, I’m not any different.”
Whether Sprotte will be able to take a device home once he finishes his training is uncertain. Depending on how well he masters the ReWalk, Gorgey said his team may recommend to Sprotte’s doctor that the VA buy him a device, which costs about $67,000.
That price may go down, though, as more and more companies are making exoskeletons that are getting approved for use by the U.S. Food & Drug Administration.
Using technology like an exoskeleton or a prosthetic can be physically and mentally exhausting, requiring people to expend energy in ways they’ve never had to before.
“Amputees constantly have to be aware of their situations, they have to look and — no matter how technologically advanced their prosthesis is — they physically have to move that prosthesis,” Lovegreen said.
BCI could change that, not just for amputees but for those with spinal cord injuries, too. Rather than having to manipulate his center of gravity so the exoskeleton moves him around, Sprotte could simply use the same thoughts and energy he used before his injury.
“Once this is out there, it will be a big save on energy because it’s just a thought,” Fox said.
If some type of BCI technology were readily available, it would impact huge numbers of amputees, both veterans and civilians.
Gadsby’s experience with the BCI was natural, he said. Previously, even with the most advanced technology, his prosthetic would react to what he was doing. If he was squatting, it would lock his knee to keep him from falling.
But there’s always a slight hesitation to it, he said, because it has to catch up with his real leg. With the BCI — it just happened.
“You’re not as tired mentally and physically, having to wait for the leg to catch up,” Gadsby said. “It was natural. I didn’t have to master it. It didn’t master me.”