The Cybathlon aims to help disabled people navigate the most difficult course of all: the everyday world.
Easily the strangest will be the brain–computer interface (BCI) race, which will feature 15 pilots sitting still for 4 minutes while large screens in the arena show what is going on in their heads. Each will attempt to guide an on-screen character through an obstacle course using specific patterns of brain activity, translated by an electrode cap into three commands: accelerate, jump over spikes or roll under laser rays.
In principle, the patterns can be anything. At the University of Essex in Colchester, UK, for instance, a team of current and former students led by postdoc Ana Matran-Fernandez has designed an algorithm that associates the three motions with a pilot thinking of his or her hand or foot, or working through a maths equation.
The electrical signals are weak, and each individual is different, so it can be difficult to distinguish between the commands — especially when a pilot is distracted, for example by cheering and adrenaline in the competition. Constantly thinking about tasks is mentally exhausting, says neuroscientist José del R. Millán of the Swiss Federal Institute of Technology in Lausanne, whose team is working on ways to predict thought patterns to make the association more natural and let the pilot relax.
BCIs will probably never be used for real jumping and running, because detecting electrical activity in muscles is much easier. But if such devices could be made cheap and accurate enough, they could help disabled people to guide wheelchairs, cursors or even Skype-enabled robots that would let them participate virtually in an event. “The fact that you can develop this in the lab and bring it out and see it works means there’s a future,” says Matran-Fernandez.
ETH Zurich / Alessandro Della Bella
Other Cybathlon events will highlight the great strides being made with more-conventional devices. In the prosthetic-leg race, competitors must get past obstacles such as stairs, randomly placed stones, tilted pavements and doors — not to mention sitting down in a chair and standing up again. Several participants will be using state-of-the-art smart knees and ankles that can detect force and acceleration as they walk, and correct their motion if they start to fall.
But even the most advanced engineering pales beside what the intact body does naturally. When a person picks up a pen with a flesh and blood arm, their brain and peripheral nervous system coordinate how far to reach, how to bend each joint in each finger into a precise shape, and how hard to grasp — all without conscious effort. Standard movable prostheses, such as the type with the hook and cables, require the user to do all of this consciously. This takes a great effort, which is one reason many amputees choose not to wear them.
To get around that, researchers have to create computer algorithms that decode signals from muscles and nerves and predict what a wearer is trying to do. In Burnaby, Canada, a Cybathlon team called MASS Impact is working with pilot Danny Letain, a former Canadian Paralympic skier who lost his left arm in a 1980 railway accident. The team has built an arm with a panel of flat buttons that sits on Letain’s arm stump.
Using his memory of a hand, Letain imagines making one of 11 gestures, such as pointing. The muscles in his stump then compress the buttons and tell his artificial hand to do what he intends. Letain was pleased to find that the brain circuitry that once controlled his fingers is still in working order, long after he stopped feeling any ‘phantom pain’ in his lost arm. “I’m using something I haven’t used in 35 years,” he says.
Some arms are even more advanced. A team led by biomedical engineer Max Ortiz Catalan at Chalmers University of Technology in Gothenburg, Sweden, has developed a two-way prosthetic hand that can feel as well as move (Sci. Transl. Med. 6, 257re6; 2014). The arm is permanently implanted in the wearer’s bone, and uses up to nine electrodes to convey motor commands from the remaining muscles to the prosthesis, and to send signals from sensors in the fingers back to the arm’s sensory nerves. Cybathlon pilot Magnus Niska is the only person in the world who wears such a prosthesis outside the lab. Ortiz Catalan hopes that the ability to feel objects will give Niska a competitive advantage. et al.
Author: Sara Reardon
Source/Full article: http://www.nature.com/news/welcome-to-the-cyborg-olympics