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BCI system gives paralyzed man back his sense of touch with haptic feedback

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Enlarge / Ian Burkhard suffered a severe spinal cord injury in 2010. Battelle’s NeuroLife project is restoring motor function to his right arm with a brain-computer-interface system.

Battelle

Ian Burkhart, now 28, had a diving accident in 2010 that severely damaged his spinal cord, leaving him paralyzed and confined to a wheelchair, with only limited movement in his elbow and shoulders. Thanks to an implanted brain-computer-interface (BCI) developed by Battelle, he has made significant progress over the last six years in restoring small movements; he’s even able to play Guitar Hero again. And now Battelle scientists have succeeded in restoring his sense of touch, according to a new paper in the journal Cell.

BCIs are a booming R&D field, with startups like Elon Musk’s Neuralink looking ahead to a world where human beings will connect directly to their computers with either external devices (similar in function to an EEG) or biologically compatible implanted BCIs. Such systems require a way to record neural activity (electrode sensors), a way to transmit those signals (like a small wireless chipset), and algorithms that can translate those signals into action. BCIs are already a medical reality for patients with spinal cord injuries, like Burkhart, or those who suffer from Parkinson’s or epileptic seizures. The benefits patients gain far outweigh the risks of surgical implantation.

Over the past 90 years or so, Battelle has been instrumental in developing such prominent technologies as the Xerox machine, cruise control, and CD-ROMs, along with numerous medical devices. Patrick Ganzer, lead author on the new Cell paper, is a research scientist with the organization’s medical devices division, working with the NeuroLife group to develop a BCI for clinical trial. Burkhart has been working with Ganzer and NeuroLife since 2014 to restore motor function to his right arm.

Researchers with Battelle's NeuroLife group have been working to restore hand function to Ian Burkhart via a BCI for several years.
Enlarge / Researchers with Battelle’s NeuroLife group have been working to restore hand function to Ian Burkhart via a BCI for several years.

Battelle’s “neural bypass system” has three primary components, according to Ganzer. The first is the surgically implanted chip, placed in an area of the brain that responds to thoughts of movement. Next, the system must take the brain wave and brain signal recordings and decode what movements the patient (in this case, Burkhart) is thinking about. “If I want to open my hand, or close my hand, those look like different activity patterns in the brain,” Ganzer told Ars. Finally, the system translates thoughts into stimulations of muscles on the arm, resulting in movement.

While the system has worked well in terms of restoring a wide range of grips and minor function to Burkhart’s paralyzed hand, his injury is so severe that he has almost no sensation in his hand. “We know how important the sense of touch is for appropriate movement control,” said Ganzer. “Even a small change in the ability to sense touch can have a really big impact on your movement control and overall upper limb function.” So if Burkhart is blindfolded, he can’t detect touch while gripping small objects like a pencil, and for larger objects like a styrofoam glass or mug, his guesses are no better than chance. He has also struggled with simple multitasking tasks like drinking a soda while watching TV, since controlling his hand with the BCI requires a great deal of concentration. 

That lack of sensation also means that Burkhart isn’t getting crucial sensory feedback, so “he doesn’t feel fully like he owns his own hand,” said Ganzer. It’s the reverse of the popular rubber hand illusion, in which the sensory feedback from the simultaneous stroking of both the real and rubber hands essentially “couples” the subject to the rubber hand, such that the brain perceives it as an extension of the physical body—what’s known as a body transfer illusion. The lack of feedback in Burkhart’s case means that critical coupling doesn’t occur.

Despite the paralysis, Ganzer and his team discovered that when they stimulated his skin, neural signals were still reaching his brain—a phenomenon known as sub-perceptual brain activity—they were just too weak for the brain to perceive them. That means Burkhart still has a few functioning nerve fibers in his arm.

So the Battelle team set about figuring out how to amplify that tiny signal with haptic feedback, like the vibrations of a mobile phone or game controller. Their system uses electrodes on the skin connected to wires that bypass the spinal cord and send those sub-perceptual touch signals to and from the BCI implanted in his motor cortex. A band of vibrational motors on Burkhart’s upper arm provides the sensory haptic feedback.

The NeuroLife group kept the haptic feedback relatively simple to establish proof of principle, since more complex sensory feedback requires a level of cognitive multi-tasking that can cause the natural feedback loop to fall apart. But the initial results were extremely promising, particularly for Burkhart’s ability to detect an object while blindfolded, relying on touch alone. “Ian operates at chance level without this touch-restoring system active,” said Ganzer. “If you activate the system and enable sub-perceptual touch to be boosted into conscious perception, his sense of object detection and touch almost goes to 100 percent. This demonstrates that you can boost a sub-perceptual signal in real time.”

The haptic feedback gives Burkhart more control over his hand movements, as well as the ability to sense the correct amount of pressure to use while picking up different objects, like a styrofoam cup, which requires a lighter grip than a heavier ceramic coffee mug. This is also the first BCI that can manage restoration of movement and the sense of touch at the same time.

“Instead of having hand grip be controlled by your volition, and your movement thought for many seconds, which can be draining, we had residual touch signals from the brain making their way past the spinal cord injury to control the magnitude of this grip,” said Ganzer. “This allows him to potentially look away from his hands, not to have to think about movement, so he could multitask.” The stimulation cuffs are cumbersome to put on and take off and are also a bit messy, since the electrode links must be adhered to the skin. So the researchers also developed a more aesthetically pleasing fabric sleeve, now being tested in clinical studies.

Ultimately, the team would like to build a version of the system that works as well at home as in the laboratory and could be controlled by a tablet rather than a desktop computer. According to Ganzer, they have successfully miniaturized the necessary electronics by an order of magnitude, so it is now portable (about the size of a VHS tape) and can be mounted on a wheelchair. Burkhart has already been able to use the system as part of his daily routine at home.

Ganzer and his team are hopeful that others with spinal cord injuries might also benefit from their system, especially since Burkhart’s injury is so severe. “This sub-perceptual touch signal is present in many patients,” he said. “It’s likely others may have a less severe injury and therefore more spare nerve fiber tissue.”

DOI: Cell, 2020. 10.1016/j.cell.2020.03.054  (About DOIs).

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Prescription poop is here: FDA approves fecal slurry for unshakeable diarrhea

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Enlarge / Laboratory technicians in France prepare stool to treat patients with serious colon infections by fecal microbiota transplantation (FMT), also known as gut flora transplant (GFT) in 2019.

For the first time, the US Food and Drug Administration has granted approval for a feces-based microbial treatment, which is used to prevent a recurring diarrheal infection that can become life-threatening.

The approval, announced Wednesday, is years in the making. Researchers have strained to harness the protective qualities of the complex, diverse, yet variable microbial communities found in healthy people’s intestines and stool. Early on, rich fecal matter proved useful for restoring balance and blocking infection in those whose microbiomes have been disturbed—a state called dysbiosis, which can occur from disease and/or use of antibiotic drugs. But, our understanding of what makes a microbiome healthy, functional, and protective remains incomplete.

Doctors, meanwhile, pushed ahead, informally trying an array of methods to transplant fecal microbiota from healthy donors to the guts of patients—via enemas, tubes through the nose, and oral poop-packed capsules. Fecal microbiota transplants (FMTs) have been used to treat various ailments, from obesity to irritable bowel syndrome, to mixed success. But it quickly became apparent that FMTs were most readily effective at preventing recurrent infection from Clostridioides difficile (C. difficile or just C. diff).

C. diff bacteria cause diarrhea and significant inflammation in the colon. Severe infections can be life-threatening. In people with dysbiosis, C. diff can proliferate in the intestines, producing toxins that can lead to organ failure. Older people, those who are hospitalized, and people with weakened immune systems are particularly susceptible to C. diff, which can recur over and over in some vulnerable patients. In the US, C. diff infections are associated with up to 30,000 deaths per year.

With the pressing need for effective treatments against C. diff, regulators were forced to wade through the mucky issue of regulating and standardizing something as unruly and myriad as fecal matter. It also led to years of microbial sleuthing, synthetic slurries, stool donations, and clinical trials.

Solid success

Now, a product has finally floated to the top: Rebyota, a blend of donor stool, saline, and laxative solution given in a single treatment as an enema. It’s teeming with heavily screened intestinal microbes at a concentration of 10,000,000 live organisms per milliliter. Its owner, Switzerland-based Ferring Pharmaceuticals, screens donors and their donated stool for a long list of infectious pathogens and other health factors.

In a Phase III clinical trial involving 262 participants—the results of which were published last month—Ferring’s scientists reported that treatment with Rebyota led to a higher prevention rate of recurrent C. diff infections than in a placebo group at a rate of 70.6 percent in the treatment group compared with 57.5 percent in the placebo group. Prevention of C. diff was defined as an absence of C. diff diarrhea for eight weeks following treatment or placebo. The treatment was well tolerated, with no serious side effects. The FDA noted that given the variability of fecal matter, there is a potential that it could contain an unforeseen infectious agent or food allergens.

The approval of Rebyota is “an advance in caring for patients who have recurrent C. difficile infection,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said in an announcement. “Recurrent CDI impacts an individual’s quality of life and can also potentially be life-threatening. As the first FDA-approved fecal microbiota product, today’s action represents an important milestone, as it provides an additional approved option to prevent recurrent CDI.”

Ferring—which acquired Rebyota in 2018 when it purchased its developer Minnestoa-based Rebiotix—also celebrated the approval.

“We believe this is a major breakthrough in harnessing the power of the human microbiome to address significant unmet medical needs. This is the first FDA approval of a live biotherapeutic and the culmination of decades of research and clinical development,” Ferring president Per Falk said. “Today’s announcement is not just a milestone for people living with recurrent C. difficile infection, but also represents a significant step which holds promise that many other diseases might be better understood, diagnosed, prevented, and treated using our rapidly evolving insights on the role of the microbiome in human health and disease.”

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Over a year later, Musk’s Neuralink still 6 months from human trials

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Enlarge / The on-stage demo of the surgical robot practically extended into the audience.

On Wednesday night, Elon Musk hosted an update from his brain-computer interface company, Neuralink. Most of the update involved various researchers at the company providing overviews of the specific areas of technology development they were working on. But there wasn’t anything dramatically new in the tech compared to last year’s update, and it was difficult to piece the presentations together into a coherent picture of what the company plans to do with its hardware.

But probably the most striking thing is that last year’s update indicated that Neuralink was getting close to human testing. Over a year later, those tests remain about six months out, according to Musk.

Lots of tech

Neuralink involves a large series of overlapping technical efforts. The interface itself requires electrodes implanted into the brain. To connect those electrodes with the outside world, Neuralink is using a small bit of hardware implanted in the skull. This contains a battery that can be recharged wirelessly, and a low-power chip that gathers data from the electrodes, performs some simple processing on it, and then transmits that data wirelessly.

Getting all that in place requires delicate neurosurgery, and the company is developing a surgical robot to make that process safe and consistent.

On the other end of the process, neural signals have to be interpreted in near real time to understand what’s happening in a given brain region. This requires computer systems that can handle everything from patient-to-patient variability to hour-to-hour differences in brain activity. Finally, in some cases, the device will need to send information back to the brain in a way that the nerve cells there can interpret (either immediately or following a learning process).

That’s… a lot of things. And the event saw people talking about almost all of them. In many cases, the information was substantially similar to what was shown the year before. Various animals with implants were shown doing everything from playing Pong to manipulating cursors and typing using their implants—more examples than last year, but not radically different. Similarly, Musk talked a bit more about the implant’s processing capacity, now provided partly by an ARM processor. There are some indications of evolutionary progress, but there are no indications that it’s close to a finalized design that’s ready for a Food and Drug Administration submission.

Perhaps the most significant difference from years prior is the level of detail involved in the surgical robot. This time, there was both an on-stage demo of the hardware and a fair bit of time spent discussing the details of the surgical procedure it was being developed for. In the previous update, the development of the robot appeared to be lagging.

We’ve been here before

The event was said to be a general overview of the company’s activities, and the presentations seemed to cover all of the key areas Neuralink is working on. But there are issues with that approach.

One is that brain implants have been an active research area for decades. While the details are different, many things Neuralink was showing off have been done before. To an extent, that’s understandable. Neuralink is developing its own electrodes, implant, and processing system. As such, it needs to demonstrate that these systems can perform like previously tested electrodes in animal experiments. But, so far, at least, Neuralink hasn’t provided any indications that its systems are superior to those that have already been tested extensively or were on a trajectory to get there.

Meanwhile, some of its competitors progressed in the areas where Neuralink sought to differentiate itself. Blackrock Neurotech, for example, is now touting fully implantable electronics that offer wireless charging and data transfer. And the company has already sent hardware through a clinical trial and is applying for FDA approval. In fact, the company has several additional clinical trials in progress.

The custom surgical robot seems unique to Neuralink (though surgical robots are widely used for other purposes). But one of the Neuralink staff mentioned that the robot was a sticking point with the FDA, saying it’s difficult to demonstrate its safety to the satisfaction of regulators. And another one of its competitors, Synchron, hopes to avoid the need for major surgery by using blood vessels to get implants deep into the brain. And those devices have also managed to go through clinical trials already.

Another problem with Neuralink’s progress update is that it doesn’t clearly indicate that the company is ready to go to the FDA. Starting a clinical trial will mean that the company has finalized a hardware design (even if it’s working on next-generation hardware separately) and chosen a specific neural defect that it plans to treat. The update’s scattershot progress reports gave no indication that any of that has been done.

None of this is to say that there won’t ultimately be space for multiple technologies in the brain-computer implant space. Neuralink will likely eventually arrive where some of these other companies are now, or it might find a niche where its hardware is especially effective. But so far, the company isn’t sharing any information that indicates that it’s close to either result—much less accomplishing some of the more outlandish claims thrown around by Musk.

Neuralink’s presentation is available online. Oddly, for an organization run by a self-professed fan of free speech, the company has disabled comments on the video.

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A new satellite has become one of the 20 brightest stars in the sky

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Enlarge / Observation of a BlueWalker 3 pass from Oukaimeden Observatory on Nov. 16 2022. The bright star lower left is Zeta Puppis.

CLEOsat/Oukaimeden Observatory/IAU CPS/A.E. Kaeouach

Last month, a Texas-based company announced that it had successfully deployed the largest-ever commercial communications satellite in low-Earth orbit.

This BlueWalker 3 demonstration satellite measures nearly 65 square meters, or about one-third the size of a tennis court. Designed and developed by AST SpaceMobile, the expansive BlueWalker 3 satellite is intended to demonstrate the ability of standard mobile phones to directly connect to the Internet via satellite. Large satellites are necessary to connect to mobile devices without a ground-based antenna.

In this emerging field of direct-to-mobile connectivity, which seeks to provide Internet service beyond the reach of terrestrial cellular towers, AST is competing with Lync, another company that also has launched demonstration satellites. In addition, larger players such as Apple and a team at SpaceX and T-Mobile have announced their intent to provide direct connectivity services.

So while there are many more such satellites coming, AST stands out at this time because it’s the first to launch an exceptionally large satellite, and it plans to start launching operational “BlueBird” satellites in late 2023.

IAU concerns

Since BlueWalker3’s launch in September, astronomers have been tracking the satellite, and their alarm was heightened following its antenna deployment last month. According to the International Astronomical Union, post-deployment measurements showed that BlueWalker 3 had an apparent visual magnitude of around 1 at its brightest, which is nearly as bright as Antares and Spica, the 15th and 16th brightest stars in the night sky.

For a few years, astronomers have been expressing concerns about megaconstellations, such as SpaceX’s Starlink satellites. While these are more numerous—there are more than 3,000 Starlink satellites in orbit—they are much smaller and far less bright than the kinds of satellites AST plans to launch. Eventually, AST plans to launch a constellation of 168 large satellites to provide “substantial” global coverage, a company spokesperson said.

Even one is enough for astronomers, however. “BlueWalker 3 is a big shift in the constellation satellite issue and should give us all reason to pause,” said Piero Benvenuti, a director at the International Astronomical Union.

The organization of astronomers is also concerned about the potential for radio interference from these “cell phone towers in space.” They will transmit strong radio waves at frequencies currently reserved for terrestrial cell phone communications but are not subject to the same radio quiet zone restrictions that ground-based cellular networks are. This could severely impact radio astronomy research—which was used to discover cosmic microwave background radiation, for example—as well as work in related fields.

Astronomers currently build their radio astronomy observatories in remote areas, far from cell tower interference. They are worried that these large, radio-wave transmitting satellites will interfere in unpopulated areas.

AST responds

An AST spokesperson provided a statement to Ars that said the impact of its satellites must be weighed against the “universal good” of cellular broadband for people on Earth. However, the company also said it is willing to work with astronomers to address their concerns.

“We are eager to use the newest technologies and strategies to mitigate possible impacts to astronomy,” the AST statement said. “We are actively working with industry experts on the latest innovations, including next-generation anti-reflective materials. We are also engaged with NASA and certain working groups within the astronomy community to participate in advanced industry solutions, including potential operational interventions.”

To that end, AST said it is committed to avoiding broadcasts inside or adjacent to the National Radio Quiet Zone in the United States, which is a large area of land that includes portions of West Virginia and Virginia, as well as additional radioastronomy locations.

A US-based astronomer who focuses on light pollution, John Barentine, told Ars he welcomed the company’s efforts to address radio interference. He also appreciates any efforts to mitigate effects on optical astronomy. However, Barentine warned, there is no recourse for astronomers but to take AST and other companies at face value due to a lack of regulatory oversight.

“Overtures by commercial space operators who commit that their activities in space will not adversely affect astronomy are made in the absence of any meaningful regulatory oversight that mandates mitigations,” he said. “AST SpaceMobile’s stated intentions are laudable, but for now, they’re just words. So I reserve judgment pending whatever actions the company takes.”

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