New sensation: Pioneering mind-controlled arm restores sense of touch
Imagine being able to control a robotic arm from a good distance, only using your brain. Now imagine having the capacity to come to feel when its fingertips grasp an object, as if it were your personal hand.
U.S. experts have published a study in the journal Research about the world's first brain-computer interface that allowed a volunteer with paralysis from the chest down to accomplish this very feat.
The team say their work demonstrates that adding a feeling of touch drastically boosts the functionality of prosthetics for quadriplegics, in comparison to having them count on visual cues alone.
"I am the first man on earth to have implants in the sensory cortex they can use to stimulate my human brain directly," Nathan Copeland, 34, told AFP. "And then I feel as though a sensation is via my actual hand."
In 2004, Copeland was in a car accident that kept him with a significant spinal-cord injury and without the usage of his hands or his legs.
He volunteered to participate in scientific analysis, and six years back underwent a major operation to have small electrodes implanted in his brain.
Two sets of 88 electrodes the width of a good strand of wild hair are arranged into "arrays" that resemble very small hairbrushes and penetrate deep into the brain's engine cortex, which directs motion.
Fewer than 30 people on the globe have these types of implants, the study's co-lead writer Rob Gaunt, an associate professor in the Department of Physical Drugs and Rehabilitation at the University of Pittsburgh, told AFP.
What's unique about Copeland can be an additional set of electrodes that are connected to his somatosensory cortex, which receives and processes sensations.
"When we're grabbing things, we utilize this sense of touch very naturally to boost our capability to control," explained Gaunt.
The team developed an interface that's "bi-directional" -- meaning not only did it "read" instructions from the mind and send them to the artificial limb, additionally, it may "write" sensations from the device and transmit them again.
The thought of sending tactile feedback to the somatosensory cortex dates back decades, but doing so in a manner that is handled and is understandable by the circuitry of the brain was a challenge.
After operating on Copeland to install the electrodes, the team held their breath.
"Not any one knew what things to expect because this had simply been done found in monkeys and you can't ask a good monkey what something feels like," said Copeland.
Then came as soon as of truth, when they tried sending their first touch signal.
"It was really faint," he recalled. He asked them to try again, to make certain it was real.
"Ok last one, that's what that feels like, and it was just super awesome," he said.
Before the interface could possibly be put to work with the robotic arm, the scientists had to execute some tests with Copeland.
First, they needed to learn which electrodes caused what sensation when activated, and which fingers they were associated with, to create the robotic hands correctly.
They also made him watch movies of the robotic arm moving left or right and recorded the electrodes that lit up when he was asked to "think" it had been him controlling it.
Finally it had been time to give it a try.
Copeland sat following to the metallic black robotic arm and was asked to get a series of small objects want rocks, spheres, and place them on a box -- with either the tactile sensors started up, or off.
He was able to complete each task typically doubly fast when the sensors were enabled, and was even in a position to achieve more technical tasks like picking right up a cup and pouring its contents into another.
"The sensation gave me personally that assurance and self confidence to learn that I definitely had an excellent grab on the thing and I could lift up it up," said Copeland.
The team wants to further refine the prosthetics because "we don't want to just conduct science experiments in the lab, we want to actually build units that are of help to people within their homes," added Gaunt.
Copeland got his brain-computer interface create in the home when the Covid pandemic shut down the university, and has used his downtime to figure out how to pull on a tablet and even play video games.
He does this through the use of his brain to send signals right to the computer, instead of using the arm to force buttons.
"It is merely second nature if you ask me now," he said.
Source: japantoday.com
