Robotic hand used to restore paralysed man's touch senses
Researchers who have been sponsored by the Defence Advanced Research Projects Agency have found a method of enabling a paralysed patient to control a prosthetic arm using their brain. Two patients had small micro-electrode arrays implanted into the cortex of their brains, which opens up a direct interface with their prosthetic limbs. After the successful movement of the limb, researchers then used advanced torque sensors attached to the fingers of the prosthetic, to electrically stimulate neurons in the brain when pressure was applied to the finger, giving the patient the sensation of touching an object.

Darpa

DARPA-sponsored researchers have figured out how to give a paralyzed man the sense of touch again and have also enabled a paralyzed woman to control a prosthetic arm using only her brain.

The subjects of DARPA's experiment, Nathan and Jan, had brain surgery to implant tiny micro-electrode arrays into the cortex of their brain, giving them a direct interface with their prosthetic limbs.

For Jan, that the power to move a prosthetic limb using only the power of her brain.

“It was all enabled by transmitting the signals directly out of her brain, processing those signals in real-time by a computer and sending the control commands directly to the robotic limb,” Justin Sanchez, a DARPA neurotechnologist, said during DARPA’s Wait, What? conference on Friday.

After the researchers were successful in using the direct brain interface to give Jan control of her motor system, they ran the experiment in reverse to see if they could use the brain interface to enable the sensation of touch for Nathan. In other words, when someone touched the robotic hand, could Nathan feel the pressure?

The researchers, who are part of DARPA's Revolutionizing Prosthetics program, used a mechanical hand built by the Applied Physics Laboratory (APL) at John Hopkins University that contained advanced torque sensors,which can detect when pressure is being applied to the fingers and convert that sensation into electrical signals that could stimulated neurons in the brain. The team then used wires to route the signal to the arrays in his brain.

“Nathan was able to sense and feel what the robotic hand was touching using only his brain,” Sanchez said. “It makes the hair on the back of my neck stand up. It’s amazing we can do this today.”

Nathan, who was blindfolded during the experiment, could distinguish which robotic finger was being touched. He was even able to discern when researchers touched two fingers at the same time.

Like Jan, Nathan was also given the ability to control the movements of the hand with his thoughts.

While this kind of neurotechnology is still in its early stages, it could hold huge promise for those who have lost a limb or who suffer from paralysis. Last year, a Colorado man who lost both of his arms in an electrical accident was enabled to control two of APL's prosthetic limbs using only his brain.

Check out the full video of Sanchez describing the experiment below.