Tag Archives: Massachusetts General Hospital (MGH)

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

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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.

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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.”

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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.

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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.

‘Glow in the dark’, paint-on bandage heals

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Somewhat unexpectedly (to me), this research about a ‘smart’ paint-on bandage is being published by The Optical Society of America (OSA). Here’s more about the work from an Oct. 1, 2014 news item on Nanowerk,

Inspired by a desire to help wounded soldiers, an international, multidisciplinary team of researchers led by Assistant Professor Conor L. Evans at the Wellman Center for Photomedicine of Massachusetts General Hospital (MGH) and Harvard Medical School (HMS) has created a paint-on, see-through, “smart” bandage that glows to indicate a wound’s tissue oxygenation concentration. Because oxygen plays a critical role in healing, mapping these levels in severe wounds and burns can help to significantly improve the success of surgeries to restore limbs and physical functions.

An Oct. 1, 2014 OSA news release (also on EurekAlert), which originated the news item, describes the interest in oxygenation in more detail,

“Information about tissue oxygenation is clinically relevant but is often inaccessible due to a lack of accurate or noninvasive measurements,” explained lead author Zongxi Li, an HMS research fellow on Evans’ team.

Now, the “smart” bandage developed by the team provides direct, noninvasive measurement of tissue oxygenation by combining three simple, compact and inexpensive components: a bright sensor molecule with a long phosphorescence lifetime and appropriate dynamic range; a bandage material compatible with the sensor molecule that conforms to the skin’s surface to form an airtight seal; and an imaging device capable of capturing the oxygen-dependent signals from the bandage with high signal-to-noise ratio.

This work is part of the team’s long-term program “to develop a Sensing, Monitoring And Release of Therapeutics (SMART) bandage for improved care of patients with acute or chronic wounds,” says Evans …

The news release goes on to briefly explain the technology,

For starters, the bandage’s not-so-secret key ingredient is phosphors—molecules that absorb light and then emit it via a process known as phosphorescence.

Phosphorescence is encountered by many on a daily basis—ranging from glow-in-the-dark dials on watches to t-shirt lettering. “How brightly our phosphorescent molecules emit light depends on how much oxygen is present,” said Li. “As the concentration of oxygen is reduced, the phosphors glow both longer and more brightly.” To make the bandage simple to interpret, the team also incorporated a green oxygen-insensitive reference dye, so that changes in tissue oxygenation are displayed as a green-to-red colormap.

The bandage is applied by “painting” it onto the skin’s surface as a viscous liquid, which dries to a solid thin film within a minute. Once the first layer has dried, a transparent barrier layer is then applied atop it to protect the film and slow the rate of oxygen exchange between the bandage and room air—making the bandage sensitive to the oxygen within tissue.

The final piece involves a camera-based readout device, which performs two functions: it provides a burst of excitation light that triggers the emission of the phosphors inside the bandage, and then it records the phosphors’ emission. “Depending on the camera’s configuration, we can measure either the brightness or color of the emitted light across the bandage or the change in brightness over time,” Li said. “Both of these signals can be used to create an oxygenation map.”  The emitted light from the bandage is bright enough that it can be acquired using a regular camera or smartphone—opening the possibility to a portable, field-ready device.

There are some immediate applications, as well as, plans for research that will yield applications (from the news release),

Immediate applications for the oxygen-sensing bandage include monitoring patients with a risk of developing ischemic (restricted blood supply) conditions, postoperative monitoring of skin grafts or flaps, and burn-depth determination as a guide for surgical debridement—the removal of dead or damaged tissue from the body.

“The need for a reliable, accurate and easy-to-use method of rapid assessment of blood flow to the skin for patients remains a clinical necessity,” said co-author Samuel Lin, an HMS associate professor of surgery at Beth Israel Deaconess Medical Center. “Plastic surgeons continuously monitor the state of blood flow to the skin, so the liquid-bandage oxygenation sensor is an exciting step toward improving patient care within the realm of vascular blood flow examination of the skin.”

What’s the next step for the bandage? “We’re developing brighter sensor molecules to improve the bandage’s oxygen sensing efficiency,” said Emmanuel Roussakis, another research fellow in Evans’ laboratory and co-author, who is leading the sensor development effort.  The team’s laboratory research will also focus on expanding the sensing capability of the bandage to other treatment-related parameters—such as pH, bacterial load, oxidative states and specific disease markers—and incorporating an on-demand drug release capacity.

“In the future, our goal for the bandage is to incorporate therapeutic release capabilities that allow for on-demand drug administration at a desired location,” says Evans. “It allows for the visual assessment of the wound bed, so treatment-related wound parameters are readily accessible without the need for bandage removal—preventing unnecessary wound disruption and reducing the chance for bacterial infection.”

Should you be interested, the researchers are looking for industry partners,

Beyond the lab, the team’s aim is to move this technology from the bench to the bedside, so they are actively searching for industry partners. They acknowledge research support from the Military Medical Photonics Program from the U.S. Department of Defense, and National Institutes of Health.

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

Non-invasive transdermal two-dimensional mapping of cutaneous oxygenation with a rapid-drying liquid bandage by Zongxi Li, Emmanuel Roussakis, Pieter G. L. Koolen, Ahmed M. S. Ibrahim, Kuylhee Kim, Lloyd F. Rose, Jesse Wu, Alexander J. Nichols, Yunjung Baek, Reginald Birngruber, Gabriela Apiou-Sbirlea, Robina Matyal, Thomas Huang, Rodney Chan, Samuel J. Lin, and Conor L. Evans. Biomedical Optics Express, Vol. 5, Issue 11, pp. 3748-3764 (2014) http://dx.doi.org/10.1364/BOE.5.003748

This article is open access.

The researcher’s have provided an illustration of the bandage,

Caption: The transparent liquid bandage displays a quantitative, oxygenation-sensitive colormap that can be easily acquired using a simple camera or smartphone. Credit: Li/Wellman Center for Photomedicine.

Caption: The transparent liquid bandage displays a quantitative, oxygenation-sensitive colormap that can be easily acquired using a simple camera or smartphone. Credit: Li/Wellman Center for Photomedicine.