Posts Tagged REINVENT

[Abstract + References] Multimodal Head-Mounted Virtual-Reality Brain-Computer Interface for Stroke Rehabilitation – Conference paper

Abstract

Rehabilitation after stroke requires the exploitation of active movement by the patient in order to efficiently re-train the affected side. Individuals with severe stroke cannot benefit from many training solutions since they have paresis and/or spasticity, limiting volitional movement. Nonetheless, research has shown that individuals with severe stroke may have modest benefits from action observation, virtual reality, and neurofeedback from brain-computer interfaces (BCIs). In this study, we combined the principles of action observation in VR together with BCI neurofeedback for stroke rehabilitation to try to elicit optimal rehabilitation gains. Here, we illustrate the development of the REINVENT platform, which takes post-stroke brain signals indicating an attempt to move and drives a virtual avatar arm, providing patient-driven action observation in head-mounted VR. We also present a longitudinal case study with a single individual to demonstrate the feasibility and potentially efficacy of the REINVENT system.

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via Multimodal Head-Mounted Virtual-Reality Brain-Computer Interface for Stroke Rehabilitation | SpringerLink

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[ARTICLE] Effects of a Brain-Computer Interface With Virtual Reality (VR) Neurofeedback: A Pilot Study in Chronic Stroke Patients – Full Text

Rehabilitation for stroke patients with severe motor impairments (e.g., inability to perform wrist or finger extension on the affected side) is burdensome and difficult because most current rehabilitation options require some volitional movement to retrain the affected side. However, although these patients participate in therapy requiring volitional movement, previous research has shown that they may receive modest benefits from action observation, virtual reality (VR), and brain-computer interfaces (BCIs). These approaches have shown some success in strengthening key motor pathways thought to support motor recovery after stroke, in the absence of volitional movement. The purpose of this study was to combine the principles of VR and BCI in a platform called REINVENT and assess its effects on four chronic stroke patients across different levels of motor impairment. REINVENT acquires post-stroke EEG signals that indicate an attempt to move and drives the movement of a virtual avatar arm, allowing patient-driven action observation neurofeedback in VR. In addition, synchronous electromyography (EMG) data were also captured to monitor overt muscle activity. Here we tested four chronic stroke survivors and show that this EEG-based BCI can be safely used over repeated sessions by stroke survivors across a wide range of motor disabilities. Finally, individual results suggest that patients with more severe motor impairments may benefit the most from EEG-based neurofeedback, while patients with more mild impairments may benefit more from EMG-based feedback, harnessing existing sensorimotor pathways. We note that although this work is promising, due to the small sample size, these results are preliminary. Future research is needed to confirm these findings in a larger and more diverse population.

Introduction

Stroke is a leading cause of adult long-term disability worldwide (Mozaffarian et al., 2015), and an increasing number of stroke survivors suffer from severe cognitive and motor impairments each year. This results in a loss of independence in their daily life, such as decreased ability to perform self-care tasks and decreased participation in social activities (Miller et al., 2010). Rehabilitation following stroke focuses on maximizing restoration of lost motor and cognitive functions and on relearning skills to better perform activities of daily living (ADLs). There is increasing evidence that the brain remains plastic at later stages after stroke, suggesting additional recovery remains possible (Page et al., 2004Butler and Page, 2006). To maximize brain plasticity, several rehabilitation strategies have been exploited, including the use of intensive rehabilitation (Wittenberg et al., 2016), repetitive motor training (Thomas et al., 2017), mirror therapy (Pérez-Cruzado et al., 2017), motor-imagery (Kho et al., 2014), and action observation (Celnik et al., 2008), amongst others.

Recently, growing evidence of the positive impact of virtual reality (VR) techniques on recovery following stroke has accumulated (Bermúdez i Badia et al., 2016). When combined with conventional therapy, VR is able to effectively incorporate rehabilitation strategies such as intensity, frequency, and duration of therapy in a novel and low-cost approach in the stroke population (Laver et al., 2017). However, patients with low levels of motor control cannot benefit from current VR tools due to their low volitional motor control, range of motion, pain, and fatigue. Rehabilitation for these individuals is challenging because most current training options require some volitional movement to train the affected side, however, research has shown that individuals with severe stroke may receive modest benefits from action observation and brain-computer interfaces (BCIs) (Silvoni et al., 2011).

Merging BCIs with VR allows for a wide range of experiences in which patients can feel immersed in various aspects of their environment. This allows patients to control their experiences in VR using only brain activity, either directly (e.g., movement in VR through explicit control) or indirectly (e.g., modulating task difficulty level based on workload as implicit control) (Vourvopoulos et al., 2016Friedman, 2017). This direct brain-to-VR communication can induce a sensorimotor contingency between the patient’s internal intentions and the environment’s responsive actions, increasing the patient’s sense of embodiment of their virtual avatar (Slater, 2009Ramos-Murguialday et al., 2013).

After a stroke resulting in severe motor impairments (e.g., inability to perform wrist or finger extension on the affected side), research shows that action observation combined with physical training enhances the effects of motor training (Celnik et al., 2008), eliciting motor-related brain activity in the lesioned hemisphere, leading to modest motor improvements (Ertelt et al., 2007Garrison et al., 2013). Moreover, action observation in a head-mounted VR increases motor activity in both healthy and the post-stroke brains (Ballester et al., 2015Vourvopoulos and Bermúdez i Badia, 2016a).

In addition, neurofeedback through BCIs has been proposed for individuals with severe stroke because BCIs do not require active motor control. Research on BCIs for rehabilitation has shown that motor-related brain signals are reinforced by rewarding feedback so they can be used to strengthen key motor pathways that are thought to support motor recovery after stroke (Wolpaw, 2012). Such feedback has previously shown modest success in motor rehabilitation for severe stroke patients (Soekadar et al., 2015).

The most common brain signal acquisition technology used with BCIs in stroke patients is non-invasive electroencephalography (EEG) (Wolpaw, 2012), which provide a cost-effective BCI platform (Vourvopoulos and Bermúdez i Badia, 2016b). In BCI paradigms for motor rehabilitation, EEG signals related to motor planning and execution are utilized. During a motor attempt, the temporal pattern of the Alpha rhythm (8–12 Hz) desynchronizes. The Alpha rhythm is also termed Rolandic mu or the sensorimotor rhythm (SMR) when it is localized over the sensorimotor cortices of the brain. Mu rhythms (8–12 Hz) are considered indirect indications of the action observation network (Kropotov, 2016) and reflect general sensorimotor activity. Mu rhythms are often detected with changes in the Beta rhythm (12–30 Hz) in the form of event-related desynchronization (ERD), in which a motor action is executed (Pfurtscheller and Lopes da Silva, 1999). These EEG rhythms, or motor-related EEG signatures, are primarily detected during task-based EEG (i.e., when the patient is actively moving or imagining movement) and used for neurofeedback.

Further, neurofeedback-induced changes in brain activity have also been linked to changes in brain activity at rest. That is, after training one’s brain activity using neurofeedback, the intrinsic, resting brain activity (i.e., EEG activity in the absence of a task) may also show changes. This resting brain activity can be used to assess more generalized brain changes, and baseline resting-state signatures may be used to predict recovery (Wu et al., 2015) or response to treatments (Zhou et al., 2018). When combined with neural injury information, resting EEG parameters can also help predict the efficacy of stroke therapy.

In this study, our goal was to combine the principles of virtual reality and BCIs to elicit optimal rehabilitation gains for stroke survivors. We hypothesized that merging BCIs with VR should induce illusions of movement and a strong feeling of embodiment within a virtual body via the action observation network, activating brain areas that overlap with those controlling actual movement, which is important for mobilizing neuroplastic changes (Dobkin, 2007). Using a VR-based BCI, those with severe stroke impairments can trigger voluntary movements of the virtual arm in a closed neurofeedback loop. This helps to increase the illusion of one’s own movements through the coordination between one’s intention and the observed first-person virtual action. Therefore, we developed a training platform called REINVENT, which uses post-stroke brain signals that indicate an attempt to move and then drives the movement of a virtual avatar arm, providing patient-driven action observation in head-mounted VR (Spicer et al., 2017). Our previous work using REINVENT with healthy individuals indeed showed that the combination of VR integrated into a BCI encouraged greater embodiment, and greater embodiment was related to greater neurofeedback performance (Anglin et al., 2019).

For this study, we recruited four chronic stroke survivors to undergo a longitudinal BCI-VR intervention using REINVENT to provide EEG-based neurofeedback with simultaneous EMG acquisition. We assessed intervention results using clinical measures, Transcranial Magnetic Stimulation (TMS) and Magnetic Resonance Imaging (MRI) and compared these measures before and after the intervention. The purpose of this study was twofold. First, we sought to determine whether REINVENT is feasible for stroke patients to use across repeated sessions and second, whether REINVENT might be able to strengthen motor-related brain signals in individuals with differing levels of motor impairment after stroke.[…]

 

Continue —>  Frontiers | Effects of a Brain-Computer Interface With Virtual Reality (VR) Neurofeedback: A Pilot Study in Chronic Stroke Patients | Frontiers in Human Neuroscience

Figure 1. System architecture of a closed neurofeedback loop. From left, (1) the evoked physiological responses are captured at the interfacing layer through the data acquisition clients, (2) sent to the processing layer where the signals are filtered and logged, and then, (3) the extracted features (e.g., EEG bands) are sent to the interaction layer where VR training occurs. Written permission to use this photo was obtained from the individual.

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[WEB SITE] How Virtual Avatars Help Stroke Patients Improve Motor Function

At USC, Dr. Sook-Lei Liew is testing whether watching a virtual avatar that moves in response to brain commands can activate portions of the brain damaged by stroke.
Dr. Sook-Lei Liew (Photo: Nate Jensen)

Photo: Nate Jensen

I am hooked up to a 16-channel brain machine interface with 12 channels of EEG on my head and ears and four channels of electromyography (EMG) on my arms. An Oculus Rift occludes my vision.

Two inertial measurement units (IMU) are stuck to my wrists and forearms, tracking the orientation of my arms, while the EMG monitors my electrical impulses and peripheral nerve activity.

Dr. Sook-Lei Liew, Director of USC’s Neural Plasticity and Neurorehabilitation Laboratory, and Julia Anglin, Research Lab Supervisor and Technician, wait to record my baseline activity and observe a monitor with a representation of my real arm and a virtual limb. I see the same image from inside the Rift.

“Ready?” asks Dr. Liew. “Don’t move—or think.”

I stay still, close my eyes, and let my mind go blank. Anglin records my baseline activity, allowing the brain-machine interface to take signals from the EEG and EMG, alongside the IMU, and use that data to inform an algorithm that drives the virtual avatar hand.

“Now just think about moving your arm to the avatar’s position,” says Dr. Liew.

I don’t move a muscle, but think about movement while looking at the two arms on the screen. Suddenly, my virtual arm moves toward the avatar appendage inside the VR world.

VR rehab at USC

Something happened just because I thought about it! I’ve read tons of data on how this works, even seen other people do it, especially inside gaming environments, but it’s something else to experience it for yourself.

“Very weird isn’t it?” says David Karchem, one of Dr. Liew’s trial patients. Karchem suffered a stroke while driving his car eight years ago, and has shown remarkable recovery using her system.

“My stroke came out of the blue and it was terrifying, because I suddenly couldn’t function. I managed to get my car through an intersection and call the paramedics. I don’t know how,” Karchem says.

He gets around with a walking stick today, and has relatively normal function on the right side of his body. However, his left side is clearly damaged from the stroke. While talking, he unwraps surgical bandages and a splint from his left hand, crooked into his chest, to show Dr. Liew the progress since his last VR session.

As a former software engineer, Karchem isn’t fazed by using advanced technology to aid the clinical process. “I quickly learned, in fact, that the more intellectual and physical stimulation you get, the faster you can recover, as the brain starts to fire. I’m something of a lab rat now and I love it,” he says.

REINVENT Yourself

Karchem is participating in Dr. Liew’s REINVENT (Rehabilitation Environment using the Integration of Neuromuscular-based Virtual Enhancements for Neural Training) project, funded by the American Heart Association, under a National Innovative Research Grant. It’s designed to help patients who have suffered strokes reconnect their brains to their bodies.

VR rehab at USC (Photo: Nate Jensen)“My PhD in Occupational Science, with a concentration in Cognitive Neuroscience, focused on how experience changes brain networks,” explains Dr. Liew. “I continued this work as a Postdoctoral Fellow at the National Institute of Neurological Disorders and Stroke at the National Institutes of Health, before joining USC, in my current role, in 2015.

“Our main goal here is to enhance neural plasticity or neural recovery in individuals using noninvasive brain stimulation, brain-computer interfaces and novel learning paradigms to improve patients’ quality of life and engagement in meaningful activities,” she says.

Here’s the science bit: the human putative mirror neuron system (MNS) is a key motor network in the brain that is active both when you perform an action, like moving your arm, and when you simply watch someone else—like a virtual avatar—perform that same action. Dr. Liew hypothesizes that, for stroke patients who can’t move their arm, simply watching a virtual avatar that moves in response to their brain commands will activate the MNS and retrain damaged or neighboring motor regions of the brain to take over the role of motor performance. This should lead to improved motor function.

“In previous occupational therapy sessions, we found many people with severe strokes got frustrated because they didn’t know if they were activating the right neural networks when we asked them to ‘think about moving’ while we physically helped them to do so,” Dr. Liew says. “If they can’t move at all, even if the right neurological signals are happening, they have no biological feedback to reinforce the learning and help them continue the physical therapy to recover.”

For many people, the knowledge that there’s “intent before movement”—in that the brain has to “think” about moving before the body will do so, is news. We also contain a “body map” inside our heads that predicts our spacetime presence in the world (so we don’t bash into things all the time and know when something is wrong). Both of these brain-body elements face massive disruption after a stroke. The brain literally doesn’t know how to help the body move.

What Dr. Liew’s VR platform has done is show patients how this causal link works and aid speedier, and less frustrating, recovery in real life.

From the Conference Hall to the Lab

She got the idea while geeking out in Northern California one day.

“I went to the Experiential Technology Conference in San Francisco in 2015, and saw demos of intersections of neuroscience and technology, including EEG-based experiments, wearables, and so on. I could see the potential to help our clinical population by building a sensory-visual motor contingency between your own body and an avatar that you’re told is ‘you,’ which provides rewarding sensory feedback to reestablish brain-body signals.

“Inside VR you start to map the two together, it’s astonishing. It becomes an automatic process. We have seen that people who have had a stroke are able to ’embody’ an avatar that does move, even though their own body, right now, cannot,” she says.

VR rehab at USC

Dr. Liew’s system is somewhat hacked together, in the best possible Maker Movement style; she built what didn’t exist and modified what did to her requirements.

“We wanted to keep costs low and build a working device that patients could actually afford to buy. We use Oculus for the [head-mounted display]. Then, while most EEG systems are $10,000 or more, we used an OpenBCI system to build our own, with EMG, for under $1,000.

“We needed an EEG cap, but most EEG manufacturers wanted to charge us $200 or more. So, we decided to hack the rest of the system together, ordering a swim cap from Amazon, taking a mallet and bashing holes in it to match up where the 12 positions on the head electrodes needed to be placed (within the 10-10 international EEG system). We also 3D print the EEG clips and IMU holders here at the lab.

VR rehab at USC

“For the EMG, we use off-the-shelf disposable sensors. This allows us to track the electromyography, if they do have trace muscular activity. In terms of the software platform, we coded custom elements in C#, from Microsoft, and implemented them in the Unity3D game engine.”

Dr. Liew is very keen to bridge the gap between academia and the tech industry; she just submitted a new academic paper with the latest successful trial results from her work for publication. Last year, she spoke at SXSW 2017 about how VR affects the brain, and debuted REINVENT at the conference’s VR Film Festival. It received a “Special Jury Recognition for Innovative Use of Virtual Reality in the Field of Health.”

Going forward, Dr. Liew would like to bring her research to a wider audience.

RELATED

“I feel the future of brain-computer interfaces splits into adaptive, as with implanted electrodes, and rehabilitative, which is what we work on. What we hope to do with REINVENT is allow patients to use our system to re-train their neural pathways, [so they] eventually won’t need it, as they’ll have recovered.

“We’re talking now about a commercial spin-off potential. We’re able to license the technology right now, but, as researchers, our focus, for the moment, is in furthering this field and delivering more trial results in published peer-reviewed papers. Once we have enough data we can use machine learning to tailor the system precisely for each patient and share our results around the world.”

If you’re in L.A., Dr. Liew and her team will be participating in the Creating Reality VR Hackathon from March 12-15 at USC. Details here.

via How Virtual Avatars Help Stroke Patients Improve Motor Function | News & Opinion | PCMag.com

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[WEB SITE] VR could trick stroke victims’ brains toward recovery.

Could virtual reality help stroke survivors regain motor function?

That’s a question Sook-Lei Liew is looking to answer.

Liew, an assistant professor at the University of Southern California and an affiliate of the Stevens Neuroimaging and Informatics Institute at the Keck School of Medicine, was inspired by research from Mel Slater and Jeremy Bailenson on embodiment in VR. If someone’s given a child’s body in VR, for example, they might start exhibiting more childlike behavior.

She wondered if giving stroke survivors with motor impairments a virtual avatar that moves properly could help promote brain plasticity (or the ability to change) and recovery. Maybe it would eventually lead to them to moving an impaired limb again.

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USC researcher Sook-Lei Liew and her partners are testing to see whether virtual reality could help with stroke rehab. Nate Jense

“So, kind of like tricking the brain through visual input,” said Liew, who is also director of the Neural Plasticity and Neurorehabilitation Laboratory. “There’s a lot of emerging evidence from neuroscience and psychology that was showing that you can really identify [with the avatar], and it changes your behavior based on the avatar you’re given in VR.”

Virtual reality is a computer-generated simulation of a 3D environment. Using a VR headset with lenses that feed images to the eyes, a person can be virtually transported to another location, or interact with a setting in a seemingly realistic way. It’s commonly been used in gaming, but it’s being tested in other environments, too — like rehab.

Implementing VR in health care and patient treatment isn’t new. It’s been used to help people overcome phobias and anxiety disorders. But the application is starting to take off now that the technology is more developed and commercially available. Some medical schools are looking to train students with virtual simulations, and it’s even helping midwives learn how to deliver babies.

Liew’s research team has been working on a study for about two years called REINVENT, an acronym for Rehabilitation Environment using the Integration of Neuromuscular-based Virtual Enhancements for Neural Training. The researchers also collaborated with the USC Institute for Creative Technologies to develop the prototype.

The process works by using a brain-computer interface, which takes a signal from the brain and uses it to control another device: a computer, a robot or, in REINVENT’s case, an avatar in VR.

Next, researchers read electrical signatures of brain activity from the surface of the scalp using electroencephalography, or EEG, for short. The team also uses electromyography, which studies the electrical activity of the muscles. That can tell them whether somebody’s moving or if they’re trying to move.

Those signals are then fed into a program on a laptop. The program has thresholds so that when specific signals in the brain or muscle activity that correspond to an attempt to move are detected, they drive the movement of a virtual arm. The resulting visual feedback through a VR headset could help strengthen neural pathways from the damaged motor cortex to the impaired arm or limb.

While the researchers could theoretically extend this process to a patient’s lower limbs, Liew said it can be dangerous for someone with a motor impairment in the lower extremities to try to move with VR, so seated studies are much safer.

The research group recently finished testing the prototype using an Oculus DK2 with 22 healthy older adults, who provided a sample of what the brain and muscle signals look like when they move. They’re now starting to test with stroke patients in a controlled lab setting, aiming to work with 10 in the short term and hundreds in the long term, in both clinical and home environments.

The team also found that giving people neurofeedback of the virtual arm moving in a VR headset was more effective than simply showing it on a screen.

“Their brain activity in the motor regions that we’re trying to target is higher, and they’re able to control the brain-computer interface a little bit better and faster,” Liew said. “It makes the case that there is an added benefit from doing this in virtual reality, which is one of the first things we wanted to know.”

An unclear future

Because VR is still a relatively new technology, there are many unanswered questions on the best ways to use it in the medical profession.

“For the most part, nobody knows how to make great VR experiences, for business or consumer,” Gartner analyst Brian Blau said. “Over time, those issues will get resolved. But for the medical industry, they have the extra added bonus of having even more types of physical behaviors that they have to either mimic or want to measure.”

And while the possibilities for VR in health care are exciting, Liew is careful not to get ahead of herself.

“We think that VR is a promising medium, but we’re moving ahead cautiously,” she said. “A lot of the work that we’re trying to do is to test assumptions, because there’s a lot of excitement about VR, but there’s not that much that’s scientifically known.”

Only time — and plenty of research — will tell.

Tech Enabled: CNET chronicles tech’s role in providing new kinds of accessibility.

The Smartest Stuff: Innovators are thinking up new ways to make you, and the things around you, smarter.

via VR could trick stroke victims’ brains toward recovery-NewsCO.com.au – newsCO.com.au

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