Technology has driven the development of prosthetic limbs by leaps and bounds. Now, the Massachusetts Institute of Technology has developed a neuroprosthetic limb that costs about $500. The smart "hand" is soft, lightweight and flexible, weighing about half a pound (about 0.23 kg).
The prosthetic hand is made of EcoFlex, a commercial elastomer. The prosthesis consists of five inflatable "fingers," each embedded with fiber segments similar to the joint bones in real fingers. Amputees can use them for everyday activities, such as zipping, pouring juice, and "jerking off". The researchers developed a controller that directs a pneumatic system to precisely inflate the "finger" and bend it into a specific position. The system includes a small pump and valve that can be worn at the waist, greatly reducing the weight of the prosthesis.
The team used an algorithm to "decode" muscle signals and associate them with common types of grasping. They also used this algorithm to program the controller of the pneumatic system. For example, when an amputee imagines holding a wine glass, sensors extract muscle signals, which the controller then translates into corresponding pressures. The pump then applies these pressures to inflate each finger, creating the grip the amputee wants.
The study found that this prosthetic limb with a haptic feedback system could restore some sensation to the amputee's residual limb, and when an object is touched or squeezed, the sensors on the prosthetic limb generate an electrical signal proportional to the sensed pressure. In addition, the new design is durable, quickly returning to its original shape after being hit by a hammer or run over by a car. "It's not a product yet, but it's close to or better than existing neural prostheses." The MIT researchers said, "The cost of this soft prosthesis is very low and the potential is huge for low-income families who have suffered amputations."