Tech
Blueprint For Touch Sensitive Prosthetic Hand that Conveys Real Time Sensory Information
Benita Matilda
First Posted: Oct 15, 2013 04:35 AM EDT
Prosthetic hands have been around for a while and researchers are continuously striving to create artificial limbs that replicate the functions of human limbs as closely as possible. Adding to the tremendous advancement in this field, is the latest work laying the groundwork for touch sensitive prosthetic limbs that move and function like the real thing.
Researchers at the University of Chicago are working toward creating a touch sensitive prosthetic hand that could convey real time sensory information to amputees through a direct interface with the brain. This latest developments mark a crucial technological step, which if applied successfully would enhance the dexterity and clinical viability of robotic prosthetic limbs.
"To restore sensory motor function of an arm, you not only have to replace the motor signals that the brain sends to the arm to move it around, but you also have to replace the sensory signals that the arm sends back to the brain. We think the key is to invoke what we know about how the brain of the intact organism processes sensory information, and then try to reproduce these patterns of neural activity through stimulation of the brain," the study's senior author, Sliman Bensmaia, PhD, assistant professor in the Department of Organismal Biology and Anatomy at the University of Chicago, said in a press statement.
This research work is a part of the Revolutionizing Prosthetics, a multi-year Defense Advanced Research Projects Agency (DARPA) project, which aims to create a modular, artificial upper limb that restores natural motor control as well as sensation in human amputees.
To develop this, the researchers conducted a series of experiments on the rhesus monkey, whose sensory system closely resembles that of humans. These monkeys were trained to respond to stimulation of the hand. In the first test, the monkeys were gently poked in the hand with the help of a physical probe at different pressures. In the second test, a few of the monkeys had electrodes implanted into the region of brain that responds to touch. In order to simulate the sensation of touch, the monkeys were given electrical pulses.
Based on the animal's response to various types of stimuli, the researchers identified the neural activity taking place during a natural object manipulation and then they induced this pattern through artificial means and repeated the same experiments with prosthetic hands that were wired to the brain implants. On touching the prosthetic hand with a physical probe they saw electrical signals were transferred to the brain.
Bensmaia stated that the monkeys performed similarly when they were poked on their hand or the prosthetic hand. The next move was on the sensation of pressure. The researchers developed an algorithm to produce the appropriate amount of electrical current to extract a sensation of pressure. They again noticed that the monkeys' responses were same if the stimuli were felt through fingers or through artificial means.
"The algorithms to decipher motor signals have come quite a long way, where you can now control arms with seven degrees of freedom. It's very sophisticated. But I think there's a strong argument to be made that they will not be clinically viable until the sensory feedback is incorporated," Bensmaia said. "When it is, the functionality of these limbs will increase substantially."
The U.S. Food and Drug Administration is in the process of approving such devices for human trials and Bensmaia hopes that his new system can be implemented within the next year.
This latest finding is documented online in the Proceedings of the National Academy of Sciences.
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First Posted: Oct 15, 2013 04:35 AM EDT
Prosthetic hands have been around for a while and researchers are continuously striving to create artificial limbs that replicate the functions of human limbs as closely as possible. Adding to the tremendous advancement in this field, is the latest work laying the groundwork for touch sensitive prosthetic limbs that move and function like the real thing.
Researchers at the University of Chicago are working toward creating a touch sensitive prosthetic hand that could convey real time sensory information to amputees through a direct interface with the brain. This latest developments mark a crucial technological step, which if applied successfully would enhance the dexterity and clinical viability of robotic prosthetic limbs.
"To restore sensory motor function of an arm, you not only have to replace the motor signals that the brain sends to the arm to move it around, but you also have to replace the sensory signals that the arm sends back to the brain. We think the key is to invoke what we know about how the brain of the intact organism processes sensory information, and then try to reproduce these patterns of neural activity through stimulation of the brain," the study's senior author, Sliman Bensmaia, PhD, assistant professor in the Department of Organismal Biology and Anatomy at the University of Chicago, said in a press statement.
This research work is a part of the Revolutionizing Prosthetics, a multi-year Defense Advanced Research Projects Agency (DARPA) project, which aims to create a modular, artificial upper limb that restores natural motor control as well as sensation in human amputees.
To develop this, the researchers conducted a series of experiments on the rhesus monkey, whose sensory system closely resembles that of humans. These monkeys were trained to respond to stimulation of the hand. In the first test, the monkeys were gently poked in the hand with the help of a physical probe at different pressures. In the second test, a few of the monkeys had electrodes implanted into the region of brain that responds to touch. In order to simulate the sensation of touch, the monkeys were given electrical pulses.
Based on the animal's response to various types of stimuli, the researchers identified the neural activity taking place during a natural object manipulation and then they induced this pattern through artificial means and repeated the same experiments with prosthetic hands that were wired to the brain implants. On touching the prosthetic hand with a physical probe they saw electrical signals were transferred to the brain.
Bensmaia stated that the monkeys performed similarly when they were poked on their hand or the prosthetic hand. The next move was on the sensation of pressure. The researchers developed an algorithm to produce the appropriate amount of electrical current to extract a sensation of pressure. They again noticed that the monkeys' responses were same if the stimuli were felt through fingers or through artificial means.
"The algorithms to decipher motor signals have come quite a long way, where you can now control arms with seven degrees of freedom. It's very sophisticated. But I think there's a strong argument to be made that they will not be clinically viable until the sensory feedback is incorporated," Bensmaia said. "When it is, the functionality of these limbs will increase substantially."
The U.S. Food and Drug Administration is in the process of approving such devices for human trials and Bensmaia hopes that his new system can be implemented within the next year.
This latest finding is documented online in the Proceedings of the National Academy of Sciences.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone