Prosthetic Arms Stimulate Nerves with Controlled Sensory Feedback

Author: University of Illinois at Urbana-Champaign
Published: 2018/04/27
Peer-Reviewed: N/A
Contents: Summary - Main - Related Publications

Synopsis: The idea is that we no longer want the prosthetic hand to feel like a tool, we want it to feel like an extension of the body.

Losing an arm doesn't have to mean losing all sense of touch, thanks to prosthetic arms that stimulate nerves with mild electrical feedback.

Main Digest

Losing an arm doesn't have to mean losing all sense of touch, thanks to prosthetic arms that stimulate nerves with mild electrical feedback.

University of Illinois researchers have developed a control algorithm that regulates the current so a prosthetics user feels steady sensation, even when the electrodes begin to peel off or when sweat builds up.

"We're giving sensation back to someone who's lost their hand. The idea is that we no longer want the prosthetic hand to feel like a tool, we want it to feel like an extension of the body," said Aadeel Akhtar, an M.D./Ph.D. student in the neuroscience program and the medical scholars program at the University of Illinois. Akhtar is the lead author of a paper describing the sensory control module, published in Science Robotics, and the founder and CEO of PSYONIC, a startup company that develops low-cost bionic arms.

"Commercial prosthetics don't have good sensory feedback. This is a step toward getting reliable sensory feedback to users of prosthetics," he said.

Continued below image.
Three pictures in one of a patient performing various everyday tasks with a sensory control module integrated with his prosthetic arm - Image Credit: Aadeel Akhtar, University of Illinois.
Three pictures in one of a patient performing various everyday tasks with a sensory control module integrated with his prosthetic arm - Image Credit: Aadeel Akhtar, University of Illinois.
Continued...

Prosthetic arms that offer nerve stimulation have sensors in the fingertips, so that when the user comes in contact with something, an electrical signal on the skin corresponds to the amount of pressure the arm exerts. For example, a light touch would generate a light sensation, but a hard push would have a stronger signal.

However, there have been many problems with giving users reliable feedback, said aerospace engineering professor Timothy Bretl, the principal investigator of the study. During ordinary wear over time, the electrodes connected to the skin can begin to peel off, causing a buildup of electrical current on the area that remains attached, which can give the user painful shocks. Alternately, sweat can impede the connection between the electrode and the skin, so that the user feels less or even no feedback at all.

"A steady, reliable sensory experience could significantly improve a prosthetic user's quality of life," Bretl said.

The controller monitors the feedback the patient is experiencing and automatically adjusts the current level so that the user feels steady feedback, even when sweating or when the electrodes are 75 percent peeled off.

The researchers tested the controller on two patient volunteers. They performed a test where the electrodes were progressively peeled back and found that the control module reduced the electrical current so that the users reported steady feedback without shocks. They also had the patients perform a series of everyday tasks that could cause loss of sensation due to sweat: climbing stairs, hammering a nail into a board and running on an elliptical machine.

"What we found is that when we didn't use our controller, the users couldn't feel the sensation anymore by the end of the activity. However, when we had the control algorithm on, after the activity they said they could still feel the sensation just fine," Akhtar said.

Adding the controlled stimulation module would cost much less than the prosthetic itself, Akhtar said. "Although we don't know yet the exact breakdown of costs, our goal is to have it be completely covered by insurance at no out-of-pocket costs to users."

The group is working on miniaturizing the module that provides the electrical feedback, so that it fits inside a prosthetic arm rather than attaching to the outside. They also plan to do more extensive patient testing with a larger group of participants.

"Once we get a miniaturized stimulator, we plan on doing more patient testing where they can take it home for an extended period of time and we can evaluate how it feels as they perform activities of daily living. We want our users to be able to reliably feel and hold things as delicate as a child's hand," Akhtar said. "This is a step toward making a prosthetic hand that becomes an extension of the body rather than just being another tool."

The National Institutes of Health and the National Science Foundation supported this work.

The paper "Controlling sensation intensity for electrotactile stimulation in human-machine interfaces" is available online or from the News Bureau - DOI: 10.1126/scirobotics.aap9770

Attribution/Source(s):

This quality-reviewed publication pertaining to our Prostheses - Prosthetics section was selected for circulation by the editors of Disabled World due to its likely interest to our disability community readers. Though the content may have been edited for style, clarity, or length, the article "Prosthetic Arms Stimulate Nerves with Controlled Sensory Feedback" was originally written by University of Illinois at Urbana-Champaign, and submitted for publishing on 2018/04/27. Should you require further information or clarification, University of Illinois at Urbana-Champaign can be contacted at illinois.edu. Disabled World makes no warranties or representations in connection therewith.

📢 Discover Related Topics


👍 Share This Information To:
𝕏.com Facebook Reddit

Page Information, Citing and Disclaimer

Disabled World is an independent disability community founded in 2004 to provide disability news and information to people with disabilities, seniors, their family and/or carers. See our homepage for informative reviews, exclusive stories and how-tos. You can connect with us on social media such as X.com and our Facebook page.

Permalink: <a href="https://www.disabled-world.com/assistivedevices/prostheses/csf.php">Prosthetic Arms Stimulate Nerves with Controlled Sensory Feedback</a>

Cite This Page (APA): University of Illinois at Urbana-Champaign. (2018, April 27). Prosthetic Arms Stimulate Nerves with Controlled Sensory Feedback. Disabled World. Retrieved February 22, 2024 from www.disabled-world.com/assistivedevices/prostheses/csf.php

Disabled World provides general information only. Materials presented are never meant to substitute for qualified professional medical care. Any 3rd party offering or advertising does not constitute an endorsement.