Mind-controlled prosthetics to help amputees

ROBOTIC limbs controlled solely by the mind could be available to paralysed people within a year.

Monkeys are being trained to control what might be the world's most sophisticated and human-like robot arm. But they never touch the prosthetic limb or fiddle with a remote control: they guide it with their thoughts alone. If trials are successful, in a few months from now people with spinal cord injuries could learn to do the same.

In 2008, Andrew Schwartz of the University of Pittsburgh in Pennsylvania published a landmark paper describing how two rhesus macaques learned to feed themselves marshmallows and fruit using a crude robotic limb controlled by electrodes implanted in their brains (Nature, DOI: 10.1038/nature06996). No brain-controlled prosthetic limb had ever carried out a more complex real-world task. Still, Schwartz envisioned a more elegant and nimble device that paralysed people could use - something much closer to a human hand.

Enter the Modular Prosthetic Limb (MPL), a bionic limb that closely approximates the form and agility of a human arm and hand. Born from the US Defense Advanced Research Projects Agency's Revolutionizing Prosthetics programme, and designed by Michael McLoughlin's team at the Johns Hopkins University Applied Physics Laboratory in Maryland, the MPL is made from a combination of lightweight carbon fibre and high-strength alloys. It has 22 degrees of freedom, compared with the human arm's 30, and can grasp precisely and firmly without crushing fragile objects. The wrist and elbow rotate with ease and, like an average human limb, it weighs just under 4.5 kilograms.

"I would say it's very close to human dexterity," says McLoughlin. "It can't do absolutely everything - it can't cup the palm, for example - but it can control all fingers individually. I don't think there is another limb that approaches it." ..

via Mind-controlled prosthetics to help amputees - health - 28 April 2011 - New Scientist.