DARPA fits paralysed volunteer with ‘feeling’ prosthetic hand
US Defense Dept’s research unit restores sense of touch to subject paralysed for more than a decade
The US Defense Advanced Research Project Agency (DARPA) has built a prosthetic hand that has allowed a human subject paralysed for more than a decade to have a sense of touch.
DARPA's Revolutionizing Prosthetics division has run a number of projects in which patients control artificial limbs directly, with neural impulses. In July, researchers successfully fitted a prosthetic limb to former US serviceman Glen Lehman.
According to a statement on DARPA's website, "the clinical work involved the placement of electrode arrays onto the paralysed 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".
The team first provided the volunteer with the ability to control the limb with thought, by running wires from the electrode arrays to the mechanical hand, which was developed by the Applied Physics Laboratory (APL) at Johns Hopkins University in Baltimore, Maryland. But without a sense of touch, manipulation of smaller objects can be difficult.
"We've completed the circuit," said Justin Sanchez, programme manager of Revolutionizing Prosthetics at DARPA. "Prosthetic limbs that can be controlled by thoughts are showing great promise, but without feedback from signals traveling back to the brain it can be difficult to achieve the level of control needed to perform precise movements. By wiring a sense of touch from a mechanical hand directly into the brain, this work shows the potential for seamless bio-technological restoration of near-natural function."
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