Researchers boost robotic arm movement by adding a sense of touch

The upgrade allowed a paralyzed participant to move objects in half the usual time.

Carlos Barria / reuters

Nathan Copeland knows a thing or two about brain implants. More than a decade after a car crash left him paralyzed from the chest down, Copeland enrolled in a medical trial that helped him to regain his sense of touch. The breakthrough saw scientists implant chips in his brain that allowed him to control a robotic hand. Back in 2016, Copeland flexed his new appendage by fist-bumping then President Barack Obama. Now, in his mid-30s, he's become the focal point of another scientific breakthrough.

Thanks to a new brain interface experiment, Copeland was able to feel the sensation of touch when his robotic hand came into contact with a surface or object. The tactile feedback allowed him to grip and move blocks and cups in half the usual time compared to tests without sensory signals — from a median of 20 seconds to 10 seconds.

Copeland was already a pro at operating his robotic arm. To make him even faster, the research team at the University of Pittsburgh placed sensors on the robotic fingertips, including torque sensors at the base of the digits, reports Wired. The four micro-electrode arrays implanted in his brain, meanwhile, read his movement commands and stimulated his sensory system.

So, when Copeland grazed or gripped an object like a ball, electrical signals from the torque sensor on the robotic hand would carry to the brain implant, which then stimulated the electrode linked to his corresponding finger.

Nathan Copeland
University of Pittsburgh Medical Center

According to Copeland, his participation in past experiments and years spent controlling the robotic arm meant the new process didn't feel alien. “I was already extremely familiar with both the sensations generated by stimulation and performing the task without stimulation. Even though the sensation isn’t ‘natural’—it feels like pressure and gentle tingle—that never bothered me,” he said.

“There wasn't really any point where I felt like stimulation was something I had to get used to. Doing the task while receiving the stimulation just went together like PB&J,” he added.

The University of Pittsburgh research team aren't the only ones exploring brain-machine interfaces. For evidence, just take the chips implanted inside Copeland's head. They were provided by Blackrock Neurotech, a rival to Elon Musk's Neuralink that sells its hardware and software to the neuroscience industry. The latest experiment also had the backing of the the Pentagon's Defense Advanced Research Projects Agency (DARPA). In addition, Sharlene Fisher, one of the researchers involved in the study, is a hardware engineer at Apple.

Though the tech is in an early proof concept stage, researchers are hailing the latest breakthrough as a step forward for brain chip interfaces. "We still have a long way to go in terms of making the sensations more realistic and bringing this technology to people’s homes, but the closer we can get to recreating the normal inputs to the brain, the better off we will be,” said co-senior author Robert Gaunt, associate professor in the Pitt Department of Physical Medicine and Rehabilitation.