In 2015, the BrainGate initiative hit a milestone when volunteers with tetraplegia were able to type using their minds. But, to accomplish this feat, participants had to be connected to a stationary computer in order for the immense amount of data to be transmitted for processing.
In a more recent breakthrough, BrainGate researchers have succeeded in creating a wireless brain-computer interface (BCI) that sidesteps this cumbersome set up, allowing users to not only type, but browse the Internet from the comfort of their own homes. A study published March 30 in IEEE Transactions on Biomedical Engineering describes how two volunteers with tetraplegia piloted the new, wireless BCI system, using it to open a Microsoft Windows start menu and enjoy a range of popular apps.
For many individuals with paralysis, their brains’ ability to “command” muscles to move remains intact, even if these signals do not reach the muscles and result in movement. BCIs work by detecting these command signals using electrodes implanted in the brain, and relaying them to a computer that uses AI for decoding. In this way, people with paralysis can imagine moving a cursor on a computer and the computer does it for them.
Until now, this tech has required a wired system to relay data, but accomplishing this wirelessly is a whole new challenge. “A wireless BCI for neural control of a cursor needs to amplify and digitize hundreds of tiny electrical signals in the [brain] and transmit them to nearby equipment continuously for hours with almost no latency,” explains John Simeral, an Assistant Professor of Research in the School of Engineering at Brown University who is involved in the BrainGate initiative.
The bandwidth and power efficiency required is “exceptional,” notes Simeral. It’s equivalent to streaming 48 high-definition videos simultaneously on a laptop, with a delay of less than 100 milliseconds. Designing a wireless transmitter capable of achieving this with low power consumption was a multi-year endeavor led by professor Arto Nurmikko, a BrainGate collaborator, and his lab at Brown University.
After years of development, the new, wireless BCI was recently tested in two study participants, a 63-year-old man and 35-year-old man, both of whom have spinal injuries resulting in tetraplegia. The two men successfully used the wireless BCI to open a Windows start up menu and use numerous apps, including Pandora, Skype, YouTube, Gmail and the Weather app. The 65-year-old participant was able to type 13.4 correct characters per minute in NotePad using the wireless system with an onscreen keyboard.
While the study participants were able to use the wireless BCI from their own homes, the researchers compared these sessions to the original, wired BCI system, finding that the two different approaches offered similar performance.
“We were really excited that the wireless system worked so well in the homes of people with tetraplegia,” says Simeral, noting that all tests of the wireless prototype to date had been under controlled laboratory settings. “Despite all of the wireless activity in the participants' living residences, and despite nearby medical equipment and even radio towers, the neural signals were recorded and decoded with high fidelity and high reliability.”
Simeral notes that this most recent advance in the field of BCIs will not be the last. He anticipates that this technology will continue to advance to a point where more individuals with severe disability will be able to benefit from it. “There remains an incredible amount to be learned about how the brain works—new understanding that will be critical to advancing BCIs in the future, and for research beyond BCIs,” he says.