Haptic Feedback Will Let Users Control Prosthetic Devices Better, Study Says

For a long time, researchers have been trying to work on giving a natural sense of muscles to prosthetic limbs. According to a research by Rice University, the University of Pisa and Italian Institute of Technology, haptic feedback could help in providing patients the ability to discern the size and feel objects without looking at them.

“Humans have an innate sense of how the parts of their bodies are positioned, even if they can’t see them. This ‘muscle sense’ is what allows people to type on a keyboard, hold a cup, throw a ball, use a brake pedal and do countless other daily tasks,” said Marcia O’Malley, professor of mechanical engineering at Rice said in the press release issued Tuesday.

Read: In Touch With Reality: Scientists Give Amputee World's First Prosthetic Touch Capable Hand

The research will be presented at the World Haptics 2017 conference, which will take place at Fürstenfeldbruck, Germany next Wednesday. It will use 18 able-bodied subjects, who would be blindfolded and asked to feel and decipher objects using a skin-stretch upper arm device, called the Rice Haptic Rocker. The Rice Haptic Rocker is a rubber pad fitted on the skin of the arm of a subject. It does not stretch when the prosthetic hand is open. As the subject closes the hand, the rubber pad stretches more.

Blindfolded subjects were asked to differentiate between objects of different sizes. Using their hands, they were able to make accurate guess 33 percent of the time. But using the device, they were able to differentiate precisely 70 percent of the time.

“We’re using the tactile sensation on the skin as a replacement for information the brain would normally get from the muscles about hand position. We’re essentially mapping from feedback from one source onto an aspect of the prosthetic hand. In this case, it’s how much the hand is open or closed,” Rice University researcher Janelle Clark stated.

According to the study, even non-invasive prosthetics, rather than embedded electrodes, could replicate the natural ‘muscle sense’. This would help the subject’s brain to process movement done by the prosthetic hand better.

“Human hands have many joints and articulations, and reproducing and controlling that in a robotic hand is very difficult. When you have to grasp something, your brain doesn’t program the movement of each finger. Your brain has patterns, called synergies, that coordinate all the joints (in the hand),” Manuel Catalano, the co-creator of the Rice Haptic Rocker, said.

Read: Robotic Leg Controlled With Thoughts: Man Becomes First Amputee To Control Prosthetic With His Mind [VIDEO]

That study states that around 1.7 million people in the U.S. suffer from the loss of a limb. Yet, the prosthetics currently available in the market don’t provide adequate sensory feedback to users. This could be improved using a combination of better computer processors, improved sensors, and vibrating motors and gain from smartphone technology, especially since the concept of tactile feedback, also known as haptics, originated with smartphone technology. In the past, this technology has been used for simple concepts such as proper gripping of mobile devices and feedback given to virtual environments.