New Prosthetic Hand Lets Paralyzed Man "Feel" Sensations

A 28-year-old who has been paralyzed for more than a decade as a result of a spinal cord injury has become the first person to be able to “feel” physical sensations through a prosthetic hand directly connected to his brain, and even identify which mechanical finger is being gently touched.
The advance, made possible by sophisticated neural technologies developed under DARPA’s (Defence Advanced Research Projects Agency) Revolutionizing Prosthetics points to a future in which people living with paralyzed or missing limbs will not only be able to manipulate objects by sending signals from their brain to robotic devices, but also be able to sense precisely what those devices are touching.
The clinical work involved the placement of electrode arrays onto the paralyzed volunteer’s sensory cortex—the brain region responsible for identifying tactile sensations such as pressure. In addition, the team placed arrays on the volunteer’s motor cortex, the part of the brain that directs body movements. Wires were run from the arrays on the motor cortex to a mechanical hand developed by the Applied Physics Laboratory (APL) at Johns Hopkins University. That gave the volunteer the capacity to control the hand’s movements with his thoughts. The researchers went on to provide the volunteer a sense of touch. A researcher blindfolded the man and then gently pressed on different fingertips in the prosthetic hand. The volunteer was able to identify which fingertip was being touched with “nearly 100 % accuracy” even without seeing it.
The idea of implanting an electrode array into the brain to either control or receive signals from a prosthetic limb is big step forward, but it is not ready for prime time yet. The biggest challenge, is that scarring can develop around the electrode in the brain, and that makes it increasingly difficult to pick up the signals that are needed.
DARPA’s investments in neurotechnologies are helping to open entirely new worlds of function and experience for individuals living with paralysis and have the potential to benefit people with similarly debilitating brain injuries or diseases,

briservNew Prosthetic Hand Lets Paralyzed Man "Feel" Sensations