An American team has successfully demonstrated a technology that allows an individual to experience the sensation of touch directly in the brain through a neural interface system connected to a robotic arm.
Researchers from the University of Pittsburgh implanted four tiny microelectrode arrays each about half the size of a shirt button into the brain of 28-year-old Nathan Copeland, who has been a quadriplegic since a car accident 12 years ago.
The implants are connected to a robotic arm and Copeland experienced interactions with the robot arm in a similar manner to when he had sensation in his own hands.
“I can feel just about every finger—it’s a really weird sensation,” he said about a month after surgery.
“Sometimes it feels electrical and sometimes it's pressure, but for the most part, I can tell most of the fingers with definite precision. It feels like my fingers are getting touched or pushed.”
Copeland is not the first to experience a brain computer interface (BCI). Four years ago, the Pit University team demonstrated a BCI that helped Jan Scheuermann, who has quadriplegia caused by a degenerative disease, feed herself chocolate using the mind-controlled robotic arm. Before that, Tim Hemmes, paralysed in a motorcycle accident, was able to reach out and touch hands with his girlfriend.
“The most important result in this study is that microstimulation of sensory cortex can elicit natural sensation instead of tingling,” said Dr Andrew B. Schwartz, chair in systems neuroscience at Pitt School of Medicine.
“This stimulation is safe, and the evoked sensations are stable over months. There is still a lot of research that needs to be carried out to better understand the stimulation patterns needed to help patients make better movements.”
Dr Robert Gaunt, who led the team, explained that everything about the work is meant to make use of the brain’s natural, existing abilities to give people back what was lost but not forgotten.
“The ultimate goal is to create a system which moves and feels just like a natural arm would,” Gaunt said. “We have a long way to go to get there, but this is a great start.”
[A researcher applies pressure to the robot fingers and Nathan Copeland is able to identify which finger is being pressed. Photo: DARPA]