Touch-Sensitive Prosthetics

The quality of prosthetics has been improving steadily over the years as researchers develop outstanding designs which allow amputees to regain much of the function of their lost limb.  Despite the advances in motor control, grip sensitivity, and dexterity, the common prosthetics of today are lacking in one major function: the sensation of touch.  Amputees are often forced to rely on sight when using their prosthetic, staring directly at any manual tasks as they perform them.

Luckily for these touch-deprived individuals, many researchers are looking into possible methods of providing touch sensitivity with prosthetics.  One of these researchers, Aadeel Akhtar, is working with the University of Illinois at Urbana-Champaign to create a new cheap prosthetic that will be available to those who cannot afford the expensive, top of the line prosthetics.  He plans on eventually adding touch sensitivity to this inexpensive prosthetic through a system of electrical feedback.  The system provides an electric current of increasing intensity as the pressure of the touch increases in intensity.  

Other researchers are taking more complicated routes, determining the specific areas of the brain that correspond to touch sensations.  Sliman Bensmaia, a neuroscientist at the University of Chicago, is working with monkeys in order to create this touch map of the brain.  Bensmaia and his colleagues trained monkeys to respond to patterns of pokes on their fingers.  Once the monkeys were regularly responding correctly, the researchers began stimulating different areas of the brain which were related to the different fingers in order to attempt to produce the same response as when the monkeys' hands were poked.  The researchers were even able to map out the pressure of a touch because light touches produce small, highly localized patterns of activation while stronger touches activate more neurons.  Now that the researchers have mapped out all of these patterns of brain activity corresponding to various touches, they can incorporate them as instructions for a robotic prosthetic arm.  It is a small step towards producing a true sensation of touch for amputees, but that goal may not be as far off as it seems.

http://www.livescience.com/40405-touch-sensitive-prosthetic-limbs-monkey-study.html

Q, Charles. "Touch-Sensitive Prosthetic Limbs Take Step Forward in Monkey Study." LiveScience. TechMedia Network, 14 Oct. 2013. Web. 01 May 2015.