Brain Computer Interface (BCI) is an emerging assistive technology technology that enables people with paralysis to type on computer screens or manipulate robotic prostheses just by thinking about moving their own bodies. For many years, 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 power external devices.
Now, for the first time, participants in clinical trials with BrainGate with tetraplegia have shown the use of an intracortical wireless BCI with an external wireless transmitter. The system is capable of transmitting brain signals with a single neuronal resolution and in full broadband fidelity without physically binding the user to a decoding system. The traditional cables are replaced by a small transmitter of about 2 inches in its largest dimension and weighs just over 1
For a study published in IEEE transactions in biomedical engineering, two paralyzed 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 write speeds.
The researchers say the study represents an early but important step toward a key goal in BCI research: a fully implantable intracortical system that helps restore independence for people who have lost the ability to move. While lower bandwidth wireless devices have been reported previously, this is the first device to transmit the full range of signals detected by an intracortical sensor. The high-speed wireless signal enables clinical research and basic human neuroscience that are much more difficult to perform with wired BCI.
The new study demonstrated some of the 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 at home, in contrast to the laboratory setting where most BCI research takes place. Unlimited with cables, participants were able to use BCI continuously for up to 24 hours, which provided researchers with data over extended periods of time, 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 head of BrainGate clinical trials. “With this system, we can look at brain activity at home over long periods of time in a way that was almost impossible before. This will help us design decoding algorithms that provide a seamless, intuitive and reliable restoration of communication and mobility for people with paralysis.”
The device used in the study was first developed at Brown in the laboratory of Arto Nurmikko, a professor at Brown’s School of Engineering. Called the Brown Wireless Device (BWD), it was designed to transmit high-security 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 BWD has been used successfully for several years in basic neuroscience research, further testing and regulatory approval was required before the system was used in the BrainGate study. Nurmikko says that the step to human use marks an important moment in the development of BCI technology.
“I am privileged to be part of a team that is pushing the boundaries of human brain brain interface,” said Nurmikko. “More importantly, the wireless technology described in our article has helped us gain crucial insight into the path forward in the pursuit of next-generation neurotechnologies, such as fully implanted high-density wireless electronic interfaces for the brain.”
The new study marks another significant advance from researchers with the BrainGate consortium, an interdisciplinary group of researchers from Brown, Stanford and Case Western Reserve universities, as well as Providence Veterans Affairs Medical Center and Massachusetts General Hospital. In 2012, the team published landmark studies in which participants in clinical trials were for the first time able to operate multidimensional robotic prostheses using a BCI. That work has been followed by a steady stream of improvements 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 cord cable to use a wireless miniature transmitter instead is an important step toward the functional use of fully implanted, high-performance neural interfaces,” said study author Sharlene Flesher, a postdoctoral fellow at Stanford and now a hardware engineer at Apple. “When the field is moving towards reducing transmitted bandwidth while maintaining the accuracy of assistive technology control, this study may be one of the few that captures the full breadth of cortical signals for extended periods, including during practical BCI use.”
The new wireless technology already provides benefits in unexpected ways, the researchers say. Because participants are able to use the wireless device at home without a technician present to maintain the wired connection, the BrainGate team has been able to continue their work during the COVID-19 pandemic.
“By March 2020, it became clear that we would not be able to visit the homes of our research participants,” said Hochberg, who is also a critical care neurologist at Massachusetts General Hospital and director of the VA Rehabilitation Research and Development Center for Neurorestoration and Neurotechnology. . “But by training caregivers on how to establish the wireless connection, a trial participant was able to use BCI without members of our team being physically there. So not only were we able to continue our research, this technology allowed us to continue the bandwidth and fidelity we had before. “
Simeral noted that, “Several companies have entered the BCI field fantastically, and some have already demonstrated human use of low-bandwidth wireless systems, including some that are fully implanted. In this report, we are pleased to have used high-bandwidth “wireless system that develops the scientific and clinical capabilities of future systems.”
Brown has a license agreement with Blackrock Microsystems to make the device available to neuroscience researchers worldwide. The BrainGate team plans to continue using the device in ongoing clinical trials.
Key bench top testing planned for wireless brain sensor
John D Simeral et al. Home use of a percutaneous wireless intracortical brain-computer interface of people with tetraplegia, IEEE transactions in biomedical engineering (2021). DOI: 10.1109 / TBME.2021.3069119
Provided by Brown University
Citation: Researchers Demonstrate First Human Use of High-bandwidth Wireless Brain Computer Interface (2021, April 1) Retrieved April 2, 2021 from https://medicalxpress.com/news/2021-04-human-high-bandwidth-wireless-brain-computer-interface .html
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