Robotic prosthetic arm with touch sensitive aesthetics
Life is never easy for an amputee and although researchers and innovative thinkers have been trying for decades to mimic god’s code they are left quite a few steps away from this goal. For example the mind-controlled prosthetic leg(s) by Long Beach Veterans Affairs Medical Center in California and Michael Goldfarb are quite intuitive giving a person who has lost his/her leg a chance to at least have some sense of free walking. On similar lines University of Chicago is on a quest for making a touch sensitive prosthetic limb that would come a feather’s distance away from the god’s code. This touch-sensitive prosthetic limb will give real time sensory information to amputee with a direct link to the brain itself. To do this their first step is to create an arm restoration sensory motor because brain sends the signal to the arm and in the same way the arm sends back the signal to brain.
This research has been published in the Proceedings of the National Academy of Sciences (PNAS) and is a part of revolutionizing Prosthetics, a Defense Advanced Research Projects Agency (DARPA) to make an artificial limb that revives the natural motor control and sensation of an amputee. According to the study’s senior author, Sliman Bensmaia (PhD, assistant professor Dept. of Organismal Biology and Anatomy, University of Chicago) the basic challenge is to understand how brain processes sensory information and then replicate the pattern through simulation of brain.
For developing this touch sensitive prosthetic arm the initial experiments are centered on sensing which part of the skin is being touched and to do this monkeys were trained to identify patterns of physical contact with fingers. Then electrodes were connected to areas of the brain for each finger and replaced by physical touches with an electrical stimuli resulting in the same response from animal as they would do for a real touch.
Next step was to work on the pressure sensation by developing an algorithm to generate electrical current resulting in positive response from the animal. And in the last step Sliman and the team developed the sensation of contact events which are activated when the object is touched or released.
All this can then be incorporated into a robotic prosthetic arm for feeding the brain with sensory signals and tested on real amputees.
# Sliman Bensmaia view on this intuitive robotic prosthetic arm development
The algorithms to decipher motor signals have come quite a long way, where you can now control arms with seven degrees of freedom. It’s very sophisticated. But I think there’s a strong argument to be made that they will not be clinically viable until the sensory feedback is incorporated. When it is, the functionality of these limbs will increase substantially.