When talking to researchers in the Department of Physical Medicine and Rehabilitation at the University of Pittsburgh, “Star Wars” is likely to come up. Specifically, the scene in “The Empire Strikes Back” when Luke Skywalker is fitted with a prosthetic hand, after losing his in a lightsaber battle with Darth Vader.
“You didn’t see how he was controlling that hand, but we think they were tapping into the signals, it was natural for him,” said Michael Boninger, vice chair for research in the department. “He thought ‘I want to move my arm.' He moved his arm.”
Boniger is principal investigator on a study that could one day lead to a futuristic prosthetic like Skywalker’s.
“We’re trying to figure out how best to tap into existing brain signals in such a way that we can understand a user’s intent and then use that intent to control devices to allow for greater independence,” he said.
Technology allowing people to control prosthetics with their minds is actually not new, and it’s being studied and refined at research institutions all over the world.
“So when you think about performing a movement, your brain actually activates in the same way as if you were moving your own arm. We can take advantage of that,” said assistant professor Jen Collinger. “We have sensors we implant into the brain where we can pick up that movement that you’re trying to perform and using that pattern of activity in your brain, we can turn that into a control signal for the robot.”
But there’s one big problem that makes controlling a robot arm with your mind difficult. You’re not getting any sensory information back. It’s hard to know how much pressure to put on an object and visual cues only help so much. So now, scientists are trying to send sensory feedback to the brain, with the help of a man named Nathan Copeland.
In 2004, Copeland was driving home in the rain and lost control of his car just 2 miles from home. He suffered a spinal cord injury and is now paralyzed, for the most part, from the neck down. He has some control of his arms, but not enough to be fully functional.
“I’ve been just taking it day by day,” he said. “This study came along, I thought it was a good chance to give back to the world.”
For the past year-and-a-half, Copeland has been working with the Pitt team to help test and refine their technology. He has four micro-electrode arrays implanted in his brain: two in the motor cortex, which controls movement, and two in the somatosensory cortex, which processes sensation.
The arrays are about a centimeter square, and on one side are 100 tiny needles, about a millimeter long and the thickness of a human hair. These arrays, implanted in Copeland’s brain, make him the first human ever to feel something he’s not actually touching.
“There’s about four or five different sensations I can feel,” he said. “The most common is a pressure or a tingling. Sometimes it’s like warm. There’s one that’s really weird and hard to describe, I just call it spidey sense. I can really just tell that something has happened, I can’t tell you really where or what it feels like.”
The research with which Nathan is involved is funded by the Defense Advanced Research Projects Agency, and was on display during the Frontiers Conference in October. The conference was a showcase for cutting edge technology, and was co-hosted by Pitt, Carnegie Mellon University and the White House.
“That’s what science does. That’s what American innovation can do,” he said. “Imagine the breakthroughs that are around the corner. Imagine what’s possible for Nathan if we keep on pushing the boundaries.”
But researchers still have a long way to go before this technology can actually improve the quality of life for Copeland or anyone else.
Inside a small room at the Rehabilitation and Neural Engineering Laboratory on Fifth Avenue, Copeland thought about grabbing each of the four objects announced by a computer.
Each object – an orange, a can of soup, a marshmallow and a tomato – required a different amount of pressure. It wasn't part of the experiment, but it’s required to get ready for this day’s experiment.
Collinger said they have to retrain the computer every day.
“The cells sort of change what they’re doing,” she said. “So even though the whole group of cells is still telling us about movement, what each one is doing is actually a little bit different from day to day.
Collinger said that’s one of the main hurdles to getting this technology out in the world, to help people with spinal cord injuries or muscular disorders. Right now, they don’t actually know how long an individual pattern of cell activity lasts.
“If they have to calibrate every four hours, that’s probably too much for somebody to do at home,” she said. “If it’s once a day, maybe that’s a little bit more realistic.”
Another huge problem, said assistant professor Rob Gaunt, is the large clunky cables coming out of the back of Copeland’s head.
“That’s not a solution,” he said. “This is a temporary thing that we need to do this research right now, but that has got to go away. We can’t send people home with those things.”
Gaunt said, ideally, this technology would be wireless. He said there are several research institutions and private companies all over the world working on that exact problem.
“I think there’s actually a lot of optimism that within a couple of years, these devices really will achieve that wireless capability,” he said. “But these are hard problems. These are the types of things that have never been done before, in terms of putting wireless devices in the human body.”
Admittedly, the robot arm being used in this research is vastly different than the lifelike prosthetic Luke Skywalker was fitted with in “The Empire Strikes Back.” But researchers say that technology is on the way. What was pure science fiction in 1980, when the film came out, is now just science in 2016.