Prosthetic hand restores sense of touch in 28-year-old

WASHINGTON: A 28-year-old paralysed man in the US has become the first person to "feel" physical sensations through a prosthetic hand directly connected to his brain, US defence researchers have claimed. Paralysed for more than a decade due to a spinal cord injury , the man could even identify which mechanical finger was being gently touched, researchers said.

The advance, made possible by neural technologies developed un der US Defence Advanced Research Projects Agency's Revolutionising Prosthetics points to a future in which paralysed people will not on y be able to manipulate objects by sending signals from their brain to devices, but also be able to sense precisely what those devices are to uching. "By wiring a sense of touch rom a mechanical hand directly in o the brain, this work shows the po ential for seamless bio-technologi cal restoration of near-natural unction," said DARPA programme manager Justin Sanchez.

Electrode arrays were placed onto the man's sensory cortex, the brain region responsible for identi ying tactile sensations such as pressure. In addition, the team pla ced arrays on his motor cortex, the part of the brain that directs body movements. Wires were run from he arrays on the motor cortex to a mechanical hand developed by the Applied Physics Laboratory (APL).

That gave the man the capacity to control the hand's movements with his thoughts.

Then, breaking new neurotechnological ground, the researchers went on to provide him the sense of touch. The mechanical hand contains sophisticated torque sensors that can detect when pressure is being applied to any of its fingers, and can convert those sensations into electrical signals. The team used wires to route those signals to the arrays on the man's brain.

In the first set of tests, in which researchers gently touched each of the prosthetic hand's fingers while the man was blindfolded, he was able to report with nearly 100% accuracy which mechanical finger was being touched, said Sanchez.