Paraplegics mentally control the robot arm
US researchers have successfully tested the use of a robotic arm in paraplegic patients. The robotic arm is operated with the help of a new "neural interface" that enables patients to control the device so precisely that they can grab a drinking bottle of coffee from the table and drink it without outside help, report John Donoghue and Leigh Hochberg from der Brown University (Rhode Island, USA) in the journal "Nature".
Since April last year, researchers have been testing the functionality of the robotic arm on two patients with quadriplegia (paraplegia that affects all limbs). With success, as the results published now prove. Cathy Hutchinson, paralyzed from the neck down, was able to direct the robot arm so precisely via a neural interface that she could take the coffee from the table and lead it to her mouth. According to the scientists, the 58-year-old has been almost completely paralyzed since a stroke 15 years ago and is no longer able to speak. For the first time, she was now able to "raise something of her own volition", explained Leigh Hochberg and added, "We will never forget her smile."
Neural interfaces as a link between man and machine "Paralysis after spinal cord injuries, brainstem infarction, amyotrophic lateral sclerosis and other disorders can separate the brain from the body, thereby eliminating the ability to perform voluntary movements", the researchers write and at the same time explain the basics of their research. Neural interfaces could be used to use brain signals to control artificial limbs, according to the approach when developing the robot arm that has now been tested. "The challenge is to decode the neural signals and convert them into digital commands that the robotic device can follow to perform the exact intended movement," the US scientists explain. The following applies: The more complex the movement, the more difficult it is to decode.
Electrode field in the brain picks up the signals for controlling the robotic arm The fact that brain signals corresponding to quadriplegia patients can also transmit them to a neural interface was already known from previous studies in which two test persons moved the cursor on a computer screen with the help of their thoughts. Controlling the robot arm, however, was significantly more complex. The neuroscientists were all the more satisfied with the success. According to the researchers, the fact that Cathy was able to grip solid objects and bring the coffee-filled bottle to her mouth in four of six attempts and drink it with a straw shows what opportunities this technique offers paraplegic patients. People with quadriplegia could use “neuronal signals” to perform multi-dimensional control of complex devices “even years after injuries to the central nervous system,” the researchers explain in the article “Reaching and grasping people using quadriplegia using a neuron-controlled robotic arm”. The neuronal interface used is an electrode field the size of an aspirin tablet with almost 100 hair-thin electrodes, which was planted in the motor cortex of the brain and converts the impulses of the neurons into commands to the robot arm, Donoghue and Hochberg continue. (fp)
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