Nav: Home

Feedback enhances brainwave control of a novel hand-exoskeleton

January 22, 2018

An extremely lightweight and portable hand exoskeleton may one day help the physically impaired with daily living. These are the hopes of EPFL scientist Luca Randazzo who is developing the exoskeleton with the Defitech Chair in Brain-Machine Interface led by José del R. Millán. The results are published in the January edition of IEEE Robotics and Automation Letters.

Their lab at Campus Biotech in Geneva is equipped with gait machines and commercial exoskeletons for walking assistance, but Randazzo started with the rudiments. "When I arrived at the lab, the first thing I added was a sewing machine so that I could develop wearable devices," he explains.

The exoskeleton is lightweight, portable and adaptable

Easily and quickly strapped to the joints with Velcro, patients are equipped with the hand-exoskeleton in just a few minutes. Metal cables act as soft tendons along the back-side of each finger, leaving the palm free in order to maximize sensations felt by the hand. A chest-pack contains motors that can push and pull on the different cables, flexing the fingers when the cables are pushed and extending them when pulled.

The exoskeleton is adaptable by design, so that the control interface can be chosen according to the residual physical ability of the patient. The control interface can then be chosen from of vast variety of systems, from eye-movement monitoring for the severely paralyzed, to smartphone-based voice interfaces, residual muscular activity of the damaged limb, all the way to reading brainwave activity with a headset.

Unexpected brain signal improves exoskeleton control

The scientists decided to pursue brainwave-control of the exoskeleton via an EEG headset that measures the users' brainwaves as they used the exoskeleton. They found that the hand motions induced by the device elicit brain patterns typical of healthy hand motions. But they also discovered that exoskeleton-induced hand motions combined with a user-driven brain-machine interface lead to peculiar brain patterns that could actually facilitate control of the device.

The part of the brain that controls body movement is called the motor cortex, which in fact is divided into a left- and a right-hand side. The right motor cortex is mostly active during control of the left hand, and vice versa, a property of the nervous system called contralateral control, contra for opposite, lateral for side.

As expected, the scientists observed this contralateral brainwave activity in people who passively received hand motion by the exoskeleton. But they also noticed that, when the subjects were asked to control the hand-exoskeleton with their brainwaves, consistent same-side patterns also emerged in the brainwave data.

In other words, when these people were asked to actively think about moving the exoskeleton, the part of the brain that normally thinks about controlling the opposite hand was also being solicited in the brain.

The scientists believe that this brain activity emerging from the combination of voluntary control and coherent feedback provided by the device could be exploited for improving brain control of these devices.

"This enhanced control of the hand-exoskeleton with brainwave activity is most likely due to higher engagement of subjects facilitated by rich sensory feedback provided by the nature of our exoskeleton," explains Millán. "Feedback is provided by the user's perception of position and movement of the hand, and this proprioception is essential."

So far, the hand-exoskeleton has been tested with patients with disabilities due to strokes and spinal cord injuries. The next steps involve improving the system both for assistive purposes, for performing tasks at home, or even as a tool for rehabilitation.

"The hope is that by combining seamless human-machine interfaces and portable devices, these kinds of systems could enable and promote functional use in meaningful daily tasks," adds Randazzo.
-end-


Ecole Polytechnique Fédérale de Lausanne

Related Brain Articles:

Study describes changes to structural brain networks after radiotherapy for brain tumors
Researchers compared the thickness of brain cortex in patients with brain tumors before and after radiation therapy was applied and found significant dose-dependent changes in the structural properties of cortical neural networks, at both the local and global level.
Blue Brain team discovers a multi-dimensional universe in brain networks
Using a sophisticated type of mathematics in a way that it has never been used before in neuroscience, a team from the Blue Brain Project has uncovered a universe of multi-dimensional geometrical structures and spaces within the networks of the brain.
New brain mapping tool produces higher resolution data during brain surgery
Researchers have developed a new device to map the brain during surgery and distinguish between healthy and diseased tissues.
Newborn baby brain scans will help scientists track brain development
Scientists have today published ground-breaking scans of newborn babies' brains which researchers from all over the world can download and use to study how the human brain develops.
New test may quickly identify mild traumatic brain injury with underlying brain damage
A new test using peripheral vision reaction time could lead to earlier diagnosis and more effective treatment of mild traumatic brain injury, often referred to as a concussion.
This is your brain on God: Spiritual experiences activate brain reward circuits
Religious and spiritual experiences activate the brain reward circuits in much the same way as love, sex, gambling, drugs and music, report researchers at the University of Utah School of Medicine.
Brain scientists at TU Dresden examine brain networks during short-term task learning
'Practice makes perfect' is a common saying. We all have experienced that the initially effortful implementation of novel tasks is becoming rapidly easier and more fluent after only a few repetitions.
Balancing time & space in the brain: New model holds promise for predicting brain dynamics
A team of scientists has extended the balanced network model to provide deep and testable predictions linking brain circuits to brain activity.
New view of brain development: Striking differences between adult and newborn mouse brain
Spikes in neuronal activity in young mice do not spur corresponding boosts in blood flow -- a discovery that stands in stark contrast to the adult mouse brain.
Map of teenage brain provides evidence of link between antisocial behavior and brain development
The brains of teenagers with serious antisocial behavior problems differ significantly in structure to those of their peers, providing the clearest evidence to date that their behavior stems from changes in brain development in early life, according to new research led by the University of Cambridge and the University of Southampton, in collaboration with the University of Rome Tor Vergata in Italy.

Related Brain Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Moving Forward
When the life you've built slips out of your grasp, you're often told it's best to move on. But is that true? Instead of forgetting the past, TED speakers describe how we can move forward with it. Guests include writers Nora McInerny and Suleika Jaouad, and human rights advocate Lindy Lou Isonhood.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...