Tag Archives: Leigh Hochberg

BrainGate demonstrates a high-bandwidth wireless brain-computer interface (BCI)

I wrote about some brain computer interface (BCI) work out of Stanford University (California, US), in a Sept. 17, 2020 posting (Turning brain-controlled wireless electronic prostheses into reality plus some ethical points), which may have contributed to what is now the first demonstration of a wireless brain-computer interface for people with tetraplegia (also known as quadriplegia).

From an April 1, 2021 news item on ScienceDaily,

In an important step toward a fully implantable intracortical brain-computer interface system, BrainGate researchers demonstrated human use of a wireless transmitter capable of delivering high-bandwidth neural signals.

Brain-computer interfaces (BCIs) are an emerging assistive technology, enabling people with paralysis to type on computer screens or manipulate robotic prostheses just by thinking about moving their own bodies. For years, investigational BCIs used in clinical trials have required cables to connect the sensing array in the brain to computers that decode the signals and use them to drive external devices.

Now, for the first time, BrainGate clinical trial participants with tetraplegia have demonstrated use of an intracortical wireless BCI with an external wireless transmitter. The system is capable of transmitting brain signals at single-neuron resolution and in full broadband fidelity without physically tethering the user to a decoding system. The traditional cables are replaced by a small transmitter about 2 inches in its largest dimension and weighing a little over 1.5 ounces. The unit sits on top of a user’s head and connects to an electrode array within the brain’s motor cortex using the same port used by wired systems.

For a study published in IEEE Transactions on Biomedical Engineering, two clinical trial participants with paralysis used the BrainGate system with a wireless transmitter to point, click and type on a standard tablet computer. The study showed that the wireless system transmitted signals with virtually the same fidelity as wired systems, and participants achieved similar point-and-click accuracy and typing speeds.

A March 31, 2021 Brown University news release (also on EurekAlert but published April 1, 2021), which originated the news item, provides more detail,

“We’ve demonstrated that this wireless system is functionally equivalent to the wired systems that have been the gold standard in BCI performance for years,” said John Simeral, an assistant professor of engineering (research) at Brown University, a member of the BrainGate research consortium and the study’s lead author. “The signals are recorded and transmitted with appropriately similar fidelity, which means we can use the same decoding algorithms we used with wired equipment. The only difference is that people no longer need to be physically tethered to our equipment, which opens up new possibilities in terms of how the system can be used.”

The researchers say the study represents an early but important step toward a major objective in BCI research: a fully implantable intracortical system that aids in restoring independence for people who have lost the ability to move. While wireless devices with lower bandwidth have been reported previously, this is the first device to transmit the full spectrum of signals recorded by an intracortical sensor. That high-broadband wireless signal enables clinical research and basic human neuroscience that is much more difficult to perform with wired BCIs.

The new study demonstrated some of those new possibilities. The trial participants — a 35-year-old man and a 63-year-old man, both paralyzed by spinal cord injuries — were able to use the system in their homes, as opposed to the lab setting where most BCI research takes place. Unencumbered by cables, the participants were able to use the BCI continuously for up to 24 hours, giving the researchers long-duration data including while participants slept.

“We want to understand how neural signals evolve over time,” said Leigh Hochberg, an engineering professor at Brown, a researcher at Brown’s Carney Institute for Brain Science and leader of the BrainGate clinical trial. “With this system, we’re able to look at brain activity, at home, over long periods in a way that was nearly impossible before. This will help us to design decoding algorithms that provide for the seamless, intuitive, reliable restoration of communication and mobility for people with paralysis.”

The device used in the study was first developed at Brown in the lab of Arto Nurmikko, a professor in Brown’s School of Engineering. Dubbed the Brown Wireless Device (BWD), it was designed to transmit high-fidelity signals while drawing minimal power. In the current study, two devices used together recorded neural signals at 48 megabits per second from 200 electrodes with a battery life of over 36 hours.

While the BWD has been used successfully for several years in basic neuroscience research, additional testing and regulatory permission were required prior to using the system in the BrainGate trial. Nurmikko says the step to human use marks a key moment in the development of BCI technology.

“I am privileged to be part of a team pushing the frontiers of brain-machine interfaces for human use,” Nurmikko said. “Importantly, the wireless technology described in our paper has helped us to gain crucial insight for the road ahead in pursuit of next generation of neurotechnologies, such as fully implanted high-density wireless electronic interfaces for the brain.”

The new study marks another significant advance by researchers with the BrainGate consortium, an interdisciplinary group of researchers from Brown, Stanford and Case Western Reserve universities, as well as the Providence Veterans Affairs Medical Center and Massachusetts General Hospital. In 2012, the team published landmark research in which clinical trial participants were able, for the first time, to operate multidimensional robotic prosthetics using a BCI. That work has been followed by a steady stream of refinements to the system, as well as new clinical breakthroughs that have enabled people to type on computers, use tablet apps and even move their own paralyzed limbs.

“The evolution of intracortical BCIs from requiring a wire cable to instead using a miniature wireless transmitter is a major step toward functional use of fully implanted, high-performance neural interfaces,” said study co-author Sharlene Flesher, who was a postdoctoral fellow at Stanford and is now a hardware engineer at Apple. “As the field heads toward reducing transmitted bandwidth while preserving the accuracy of assistive device control, this study may be one of few that captures the full breadth of cortical signals for extended periods of time, including during practical BCI use.”

The new wireless technology is already paying dividends in unexpected ways, the researchers say. Because participants are able to use the wireless device in their homes without a technician on hand to maintain the wired connection, the BrainGate team has been able to continue their work during the COVID-19 pandemic.

“In March 2020, it became clear that we would not be able to visit our research participants’ homes,” said Hochberg, who is also a critical care neurologist at Massachusetts General Hospital and director of the V.A. Rehabilitation Research and Development Center for Neurorestoration and Neurotechnology. “But by training caregivers how to establish the wireless connection, a trial participant was able to use the BCI without members of our team physically being there. So not only were we able to continue our research, this technology allowed us to continue with the full bandwidth and fidelity that we had before.”

Simeral noted that, “Multiple companies have wonderfully entered the BCI field, and some have already demonstrated human use of low-bandwidth wireless systems, including some that are fully implanted. In this report, we’re excited to have used a high-bandwidth wireless system that advances the scientific and clinical capabilities for future systems.”

Brown has a licensing agreement with Blackrock Microsystems to make the device available to neuroscience researchers around the world. The BrainGate team plans to continue to use the device in ongoing clinical trials.

Here’s a link to and a citation for the paper,

Home Use of a Percutaneous Wireless Intracortical Brain-Computer Interface by Individuals With Tetraplegia by John D Simeral, Thomas Hosman, Jad Saab, Sharlene N Flesher, Marco Vilela, Brian Franco, Jessica Kelemen, David M Brandman, John G Ciancibello, Paymon G Rezaii, Emad N. Eskandar, David M Rosler, Krishna V Shenoy, Jaimie M. Henderson, Arto V Nurmikko, Leigh R. Hochberg. IEEE Transactions on Biomedical Engineering, 2021; 1 DOI: 10.1109/TBME.2021.3069119 Date of Publication: 30 March 2021

This paper is open access.

If you don’t happen to be familiar with the IEEE, it’s the Institute of Electrical and Electronics Engineers. BrainGate can be found here, and Blackrock Microsystems can be found here.

The first story here to feature BrainGate was in a May 17, 2012 posting. (Unfortunately, the video featuring a participant picking up a cup of coffee is no longer embedded in the post.) There’s also an October 31, 2016 posting and an April 24, 2017 posting, both of which mention BrainGate. As for my Sept. 17, 2020 posting (Turning brain-controlled wireless electronic prostheses into reality plus some ethical points), you may want to look at those ethical points.

Quadriplegic man reanimates a limb with implanted brain-recording and muscle-stimulating systems

It took me a few minutes to figure out why this item about a quadriplegic (also known as, tetraplegic) man is news. After all, I have a May 17, 2012 posting which features a video and information about a quadri(tetra)plegic woman who was drinking her first cup of coffee, independently, in many years. The difference is that she was using an external robotic arm and this man is using *his own arm*,

This Case Western Reserve University (CRWU) video accompanies a March 28, 2017 CRWU news release, (h/t ScienceDaily March 28, 2017 news item)

Bill Kochevar grabbed a mug of water, drew it to his lips and drank through the straw.

His motions were slow and deliberate, but then Kochevar hadn’t moved his right arm or hand for eight years.

And it took some practice to reach and grasp just by thinking about it.

Kochevar, who was paralyzed below his shoulders in a bicycling accident, is believed to be the first person with quadriplegia in the world to have arm and hand movements restored with the help of two temporarily implanted technologies.

A brain-computer interface with recording electrodes under his skull, and a functional electrical stimulation (FES) system* activating his arm and hand, reconnect his brain to paralyzed muscles.

Holding a makeshift handle pierced through a dry sponge, Kochevar scratched the side of his nose with the sponge. He scooped forkfuls of mashed potatoes from a bowl—perhaps his top goal—and savored each mouthful.

“For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me,” said Kochevar, 56, of Cleveland. “It’s better than I thought it would be.”

Kochevar is the focal point of research led by Case Western Reserve University, the Cleveland Functional Electrical Stimulation (FES) Center at the Louis Stokes Cleveland VA Medical Center and University Hospitals Cleveland Medical Center (UH). A study of the work was published in the The Lancet March 28 [2017] at 6:30 p.m. U.S. Eastern time.

“He’s really breaking ground for the spinal cord injury community,” said Bob Kirsch, chair of Case Western Reserve’s Department of Biomedical Engineering, executive director of the FES Center and principal investigator (PI) and senior author of the research. “This is a major step toward restoring some independence.”

When asked, people with quadriplegia say their first priority is to scratch an itch, feed themselves or perform other simple functions with their arm and hand, instead of relying on caregivers.

“By taking the brain signals generated when Bill attempts to move, and using them to control the stimulation of his arm and hand, he was able to perform personal functions that were important to him,” said Bolu Ajiboye, assistant professor of biomedical engineering and lead study author.

Technology and training

The research with Kochevar is part of the ongoing BrainGate2* pilot clinical trial being conducted by a consortium of academic and VA institutions assessing the safety and feasibility of the implanted brain-computer interface (BCI) system in people with paralysis. Other investigational BrainGate research has shown that people with paralysis can control a cursor on a computer screen or a robotic arm (braingate.org).

“Every day, most of us take for granted that when we will to move, we can move any part of our body with precision and control in multiple directions and those with traumatic spinal cord injury or any other form of paralysis cannot,” said Benjamin Walter, associate professor of neurology at Case Western Reserve School of Medicine, clinical PI of the Cleveland BrainGate2 trial and medical director of the Deep Brain Stimulation Program at UH Cleveland Medical Center.

“The ultimate hope of any of these individuals is to restore this function,” Walter said. “By restoring the communication of the will to move from the brain directly to the body this work will hopefully begin to restore the hope of millions of paralyzed individuals that someday they will be able to move freely again.”

Jonathan Miller, assistant professor of neurosurgery at Case Western Reserve School of Medicine and director of the Functional and Restorative Neurosurgery Center at UH, led a team of surgeons who implanted two 96-channel electrode arrays—each about the size of a baby aspirin—in Kochevar’s motor cortex, on the surface of the brain.

The arrays record brain signals created when Kochevar imagines movement of his own arm and hand. The brain-computer interface extracts information from the brain signals about what movements he intends to make, then passes the information to command the electrical stimulation system.

To prepare him to use his arm again, Kochevar first learned how to use his brain signals to move a virtual-reality arm on a computer screen.

“He was able to do it within a few minutes,” Kirsch said. “The code was still in his brain.”

As Kochevar’s ability to move the virtual arm improved through four months of training, the researchers believed he would be capable of controlling his own arm and hand.

Miller then led a team that implanted the FES systems’ 36 electrodes that animate muscles in the upper and lower arm.

The BCI decodes the recorded brain signals into the intended movement command, which is then converted by the FES system into patterns of electrical pulses.

The pulses sent through the FES electrodes trigger the muscles controlling Kochevar’s hand, wrist, arm, elbow and shoulder. To overcome gravity that would otherwise prevent him from raising his arm and reaching, Kochevar uses a mobile arm support, which is also under his brain’s control.

New Capabilities

Eight years of muscle atrophy required rehabilitation. The researchers exercised Kochevar’s arm and hand with cyclical electrical stimulation patterns. Over 45 weeks, his strength, range of motion and endurance improved. As he practiced movements, the researchers adjusted stimulation patterns to further his abilities.

Kochevar can make each joint in his right arm move individually. Or, just by thinking about a task such as feeding himself or getting a drink, the muscles are activated in a coordinated fashion.

When asked to describe how he commanded the arm movements, Kochevar told investigators, “I’m making it move without having to really concentrate hard at it…I just think ‘out’…and it goes.”

Kocehvar is fitted with temporarily implanted FES technology that has a track record of reliable use in people. The BCI and FES system together represent early feasibility that gives the research team insights into the potential future benefit of the combined system.

Advances needed to make the combined technology usable outside of a lab are not far from reality, the researchers say. Work is underway to make the brain implant wireless, and the investigators are improving decoding and stimulation patterns needed to make movements more precise. Fully implantable FES systems have already been developed and are also being tested in separate clinical research.

Kochevar welcomes new technology—even if it requires more surgery—that will enable him to move better. “This won’t replace caregivers,” he said. “But, in the long term, people will be able, in a limited way, to do more for themselves.”

There is more about the research in a March 29, 2017 article by Sarah Boseley for The Guardian,

Bill Kochevar, 53, has had electrical implants in the motor cortex of his brain and sensors inserted in his forearm, which allow the muscles of his arm and hand to be stimulated in response to signals from his brain, decoded by computer. After eight years, he is able to drink and feed himself without assistance.

“I think about what I want to do and the system does it for me,” Kochevar told the Guardian. “It’s not a lot of thinking about it. When I want to do something, my brain does what it does.”

The experimental technology, pioneered by the Case Western Reserve University in Cleveland, Ohio, is the first in the world to restore brain-controlled reaching and grasping in a person with complete paralysis.

For now, the process is relatively slow, but the scientists behind the breakthrough say this is proof of concept and that they hope to streamline the technology until it becomes a routine treatment for people with paralysis. In the future, they say, it will also be wireless and the electrical arrays and sensors will all be implanted under the skin and invisible.

A March 28, 2017 Lancet news release on EurekAlert provides a little more technical insight into the research and Kochevar’s efforts,

Although only tested with one participant, the study is a major advance and the first to restore brain-controlled reaching and grasping in a person with complete paralysis. The technology, which is only for experimental use in the USA, circumvents rather than repairs spinal injuries, meaning the participant relies on the device being implanted and switched on to move.

“Our research is at an early stage, but we believe that this neuro-prosthesis could offer individuals with paralysis the possibility of regaining arm and hand functions to perform day-to-day activities, offering them greater independence,” said lead author Dr Bolu Ajiboye, Case Western Reserve University, USA. “So far it has helped a man with tetraplegia to reach and grasp, meaning he could feed himself and drink. With further development, we believe the technology could give more accurate control, allowing a wider range of actions, which could begin to transform the lives of people living with paralysis.” [1]

Previous research has used similar elements of the neuro-prosthesis. For example, a brain-computer interface linked to electrodes on the skin has helped a person with less severe paralysis open and close his hand, while other studies have allowed participants to control a robotic arm using their brain signals. However, this is the first to restore reaching and grasping via the system in a person with a chronic spinal cord injury.

In this study, a 53 year-old man who had been paralysed below the shoulders for eight years underwent surgery to have the neuro-prosthesis fitted.

This involved brain surgery to place sensors in the motor cortex area of his brain responsible for hand movement – creating a brain-computer interface that learnt which movements his brain signals were instructing for. This initial stage took four months and included training using a virtual reality arm.

He then underwent another procedure placing 36 muscle stimulating electrodes into his upper and lower arm, including four that helped restore finger and thumb, wrist, elbow and shoulder movements. These were switched on 17 days after the procedure, and began stimulating the muscles for eight hours a week over 18 weeks to improve strength, movement and reduce muscle fatigue.

The researchers then wired the brain-computer interface to the electrical stimulators in his arm, using a decoder (mathematical algorithm) to translate his brain signals into commands for the electrodes in his arm. The electrodes stimulated the muscles to produce contractions, helping the participant intuitively complete the movements he was thinking of. The system also involved an arm support to stop gravity simply pulling his arm down.

During his training, the participant described how he controlled the neuro-prosthesis: “It’s probably a good thing that I’m making it move without having to really concentrate hard at it. I just think ‘out’ and it just goes.”

After 12 months of having the neuro-prosthesis fitted, the participant was asked to complete day-to-day tasks, including drinking a cup of coffee and feeding himself. First of all, he observed while his arm completed the action under computer control. During this, he thought about making the same movement so that the system could recognise the corresponding brain signals. The two systems were then linked and he was able to use it to drink a coffee and feed himself.

He successfully drank in 11 out of 12 attempts, and it took him roughly 20-40 seconds to complete the task. When feeding himself, he did so multiple times – scooping forkfuls of food and navigating his hand to his mouth to take several bites.

“Although similar systems have been used before, none of them have been as easy to adopt for day-to-day use and they have not been able to restore both reaching and grasping actions,” said Dr Ajiboye. “Our system builds on muscle stimulating electrode technology that is already available and will continue to improve with the development of new fully implanted and wireless brain-computer interface systems. This could lead to enhanced performance of the neuro-prosthesis with better speed, precision and control.” [1]

At the time of the study, the participant had had the neuro-prosthesis implanted for almost two years (717 days) and in this time experienced four minor, non-serious adverse events which were treated and resolved.

Despite its achievements, the neuro-prosthesis still had some limitations, including that movements made using it were slower and less accurate than those made using the virtual reality arm the participant used for training. When using the technology, the participant also needed to watch his arm as he lost his sense of proprioception – the ability to intuitively sense the position and movement of limbs – as a result of the paralysis.

Writing in a linked Comment, Dr Steve Perlmutter, University of Washington, USA, said: “The goal is futuristic: a paralysed individual thinks about moving her arm as if her brain and muscles were not disconnected, and implanted technology seamlessly executes the desired movement… This study is groundbreaking as the first report of a person executing functional, multi-joint movements of a paralysed limb with a motor neuro-prosthesis. However, this treatment is not nearly ready for use outside the lab. The movements were rough and slow and required continuous visual feedback, as is the case for most available brain-machine interfaces, and had restricted range due to the use of a motorised device to assist shoulder movements… Thus, the study is a proof-of-principle demonstration of what is possible, rather than a fundamental advance in neuro-prosthetic concepts or technology. But it is an exciting demonstration nonetheless, and the future of motor neuro-prosthetics to overcome paralysis is brighter.”

[1] Quote direct from author and cannot be found in the text of the Article.

Here’s a link to and a citation for the paper,

Restoration of reaching and grasping movements through brain-controlled muscle stimulation in a person with tetraplegia: a proof-of-concept demonstration by A Bolu Ajiboye, Francis R Willett, Daniel R Young, William D Memberg, Brian A Murphy, Jonathan P Miller, Benjamin L Walter, Jennifer A Sweet, Harry A Hoyen, Michael W Keith, Prof P Hunter Peckham, John D Simeral, Prof John P Donoghue, Prof Leigh R Hochberg, Prof Robert F Kirsch. The Lancet DOI: http://dx.doi.org/10.1016/S0140-6736(17)30601-3 Published: 28 March 2017 [online?]

This paper is behind a paywall.

For anyone  who’s interested, you can find the BrainGate website here.

*I initially misidentified the nature of the achievement and stated that Kochevar used a “robotic arm, which is attached to his body” when it was his own reanimated arm. Corrected on April 25, 2017.