A brain computer interface has allowed a quadriplegic to once again experience the sensation of touch through a mind-controlled robotic arm directly connected to his brain. This is the first ever demonstration of a technology that allows patients to experience touch sensations through a robotic system controlled by their thought.

The study that produced the brain computer interface (BCI) was a collaboration between the University of Pittsburgh and UPMC, but not the team’s first attempt at the technology.

Previous attempts allowed another quadriplegic, Jan Scheuermann, to use a robotic arm to feed herself chocolates, while Tim Hemmes, paralysed in a motorcycle accident, was able to reach out and touch hands with his girlfriend. The latest attempt, however, is the first to achieve a real sensation of touch.

“The most important result in this study is that microstimulation of sensory cortex can elicit natural sensation instead of tingling,” said study co-author Dr Andrew B Schwartz, distinguished professor of neurobiology and chair in systems neuroscience, Pitt School of Medicine, and a member of the University of Pittsburgh Brain Institute. “This stimulation is safe, and the evoked sensations are stable over months.”

The importance of touch to a technology like the BCI is paramount as the constant feedback sensations of touch are what tell the brain where to move and by how much.

Establishing such a sensation through robotics has proved complicated, but by refining their previous attempts the research team were, in partnership with Blackrock Microsystems, able to develop a microelectrode array that was implanted in the brain where the neurons that control hand movement and touch are located. Inputs from the robotic arm are transmitted through the array to connect the brain to what is happening with the arm.

The patient in the study, Nathan Copeland, was paralysed in the winter of 2004 following a car accident that snapped his neck and injured his spinal cord, leaving him with quadriplegia from the upper chest down.

Having enrolled for clinical trials following his accident, after passing screening tests for the new study, Copeland was wheeled into the operating room where four tiny microelectrode arrays each about half the size of a shirt button were implanted in his brain.

“I can feel just about every finger – it’s a really weird sensation,” Copeland said about a month after surgery. “Sometimes it feels electrical and sometimes its 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.”

The study represents an amazing step forward in returning lost sensations to those who have suffered accidents, and ultimately aims to create a system that moves and feels just like a natural arm.

This BCI is a first step to technology that could restore touch to those who have long thought it gone, however much needs to be done before this can become a viable, approved treatment

“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,” said Schwartz.

In the long run, however, the researchers hope to create a system that makes full use of the brain’s own natural abilities.

“The ultimate goal is to create a system which moves and feels just like a natural arm would,” said study lead author Dr Robert Gaunt, assistant professor of physical medicine and rehabilitation at Pitt. “We have a long way to go to get there, but this is a great start.”