Robotic hand provides paralyzed man with 'near-natural' sense of touch

Scientists reveal how a 28-year-old paralyzed man has become the first person to regain a "near-natural" sense of touch with the help of a robotic hand directly connected to his brain.

With the help of a robotic hand connected to the brain, a 28-year-old man was able to detect pressure to the hand with near-perfect accuracy.
Image credit: Justin Sanchez

According to the Defense Advanced Research Projects Agency (DARPA) - an agency of the USA Department of Defense who enabled the development through their Revolutionizing Prosthetics program - the unnamed man was able to identify which finger of the robotic device was being gently touched with almost 100% accuracy.

At one point, instead of pressing one finger, the research team decided to press two without telling him. He responded in jest asking whether somebody was trying to play a trick on him. That is when we knew that the feelings he was perceiving through the robotic hand were near-natural.

The research leader presented the findings at DARPA's Wait, What? A Future Technology Forum in St. Louis, MO, last week.

These latest results represent another step toward artificial limbs that provide individuals who are paralyzed or who have missing limbs with a sense of touch.

Potential for 'seamless biotechnological restoration of near-natural function'

Created by the scientists from the Applied Physics Laboratory at Johns Hopkins University in Baltimore, MD, the robotic hand contains "torque sensors" in each finger that can detect when pressure is applied to them.

A number of wires connect the robotic hand to electrode arrays that are implanted into the sensory cortex - the area of the brain responsible for sensation - and the motor cortex - the brain region responsible for body movement.

When pressure is placed on the sensors of the robotic hand, electrical signals are sent to the brain that simulate touch sensation.

The researchers tested the robotic hand on the 28-year-old volunteer, who was left paralyzed following a spinal cord injury 10 years ago.

The scientists gently touched each finger of the robotic hand while the man was blindfolded.

Not only was he able to control movement of the mechanical hand with his thoughts, he was able to detect which finger the researchers were putting pressure on with near-perfect accuracy. The man reported feeling as if his own hand was being touched, according to the scientists.

The researchers believe their creation paves the way for robotic limbs that could simulate a natural sense of touch. 

"Prosthetic limbs that can be controlled by thoughts are showing great promise, but without feedback from signals traveling back to the brain, it can be difficult to achieve the level of control needed to perform precise movements.

By wiring a sense of touch from a mechanical hand directly into the brain, this work shows the potential for seamless biotechnological restoration of near-natural function. We've completed the circuit."

In a report published in The Lancet earlier this year, scientists revealed how mind-controlled robotic hands allowed three Austrian men with debilitating nerve injuries to regain hand function, allowing them to carry out everyday tasks such as chopping food with a knife.

References:

DARPA news release, accessed 14 September 2015.