Health Issue: Brain chip to help paralysed patients

Brain chip to help paralysed patients move bionic limbs London: Scientists have developed a brain chip that will help paralysed patients operate their bionic limbs.       The techology emplys tiny microchips to sense nerve messages, decode the signals, and turn thought into movement. The scientists hope that with in five years they will be able to offer patients with damaged spinal cords robotic devices that will enable them to move their arms or legs at will.       Rodrigo Quian Quioga heading a University of Leicester team working onthe project, said such patients retain the ability to "think" commands from the brain, reoprts telegraph.co.uk.        "The guy can see the object he wants to reach, the guy can have the intention to reach to the object, the brain can send a command to the arm - 'reach for this cup of tea' - but the signal gets broken at the level of the spinal cord," he said.         "If we can get the signals from these neurons and interpret them with what is called decoding algorithms, then we can move a robot device placed on the paralysed arm," he added.          The more ambitious idea is not touse robotic devices but to replace the broken connection to the limb with an artificial link. The brain chip would then send signals to an implanted stimulator in the spinal cord. This would generate electrical impulses to make muscles contract and move parlysed limbs.          For those who rely on binic arms, the process of muscle reinnervation is what makes them functional. First developed by Dr Todd Kuiken, director of neuroengineering at the Center for Artificial Limbs at the Rehabilitation Institute of Chicago, the procedure involves grafting shoulder nerves to the pectoral muscle.           The grafts receive thought generated impulses, and the activity is sensed by electrodes within the muscle. The electrodes relay the signals to the arm's computer, which causes motors to move the elbow and hand. Hence, when amputee Jesse Sullivan thinks. "Close hand," electrical signals sent through surgically re-routed nerves make it happen. Moreover, unlike typical artificial arms, there is no perceivable delay in motion.           Gregory Clark, assoicate professor of bioengineering and a prosthetics researcher at the University Utah, says that convertional prosthetic limbs are problematic because they "can do only one movement at any particular moment". However, Sullivan says his bionic arm allows him to rotate his upper arm, bend his elbow, rotate his wrist, and open and close his hand - in some instances simultaneously.