The investigational BrainGate BCI includes a baby aspirin-sized implant that detects the signals associated with intended movements produced in the brain’s motor cortex. Those signals are then decoded and routed to external devices. BrainGate researchers and other groups using similar technologies have shown that the device can enable people to move robotic arms or to regain control of their own limbs, despite having lost motor abilities from illness or injury. This study from the collaboration includes scientists, engineers and physicians from Brown University’s Carney Institute for Brain Science, the Providence Veterans Affairs Medical Center (PVAMC), Massachusetts General Hospital (MGH) and Stanford University.
Two of the participants in this latest study had weakness or loss of movement of their arms and legs due to amyotrophic lateral sclerosis (ALS), a progressive disease affecting the nerves in the brain and spine that control movement. The third participant was paralyzed due to a spinal cord injury. All were enrolled in a clinical trial aimed at assessing the safety and feasibility of the investigational BrainGate system.
For this study, neural signals from the BrainGate BCI were routed to a Bluetooth interface configured to work like a wireless mouse. The virtual mouse was then paired to an unmodified Google Nexus 9 tablet. The participants were then asked to perform a set of tasks designed to see how well they were able to navigate within a variety of commonly used apps, and move from app to app. The participants browsed through music selections on a streaming service, searched for videos on YouTube, scrolled through a news aggregator and composed emails and chats.
The study showed that participants were able to make up to 22 point-and-click selections per minute while using a variety of apps. In text apps, the participants were able to type up to 30 effective characters per minute using standard email and text interfaces.
The participants reported finding the interface intuitive and fun to use, the study noted. One said, “It felt more natural than the times I remember using a mouse.” Another reported having “more control over this than what I normally use.”
The researchers were pleased to see how quickly the participants used the tablet interface to explore their hobbies and interests.
“It was great to see our participants make their way through the tasks we asked them to perform, but the most gratifying and fun part of the study was when they just did what they wanted to do — using the apps that they liked for shopping, watching videos or just chatting with friends,” said lead author Dr. Paul Nuyujukian, a bioengineer at Stanford. “One of the participants told us at the beginning of the trial that one of the things she really wanted to do was play music again. So to see her play on a digital keyboard was fantastic.”
The fact that the tablet devices were entirely unaltered and had all preloaded accessibility software turned off was an important part of the study, the researchers said.
“The assistive technologies that are available today, while they’re important and useful, are all inherently limited in terms of either the speed of use they enable, or the flexibility of the interface,” said Krishna Shenoy, a senior author of the paper and an electrical engineer and neuroscientist at Stanford University and Howard Hughes Medical Institute. “That’s largely because of the limited input signals that are available. With the richness of the input from the BCI, we were able to just buy two tablets on Amazon, turn on Bluetooth and the participants could use them with our investigational BrainGate system right out of the box.”
The researchers say that the study also has the potential to open important new lines of communication between patients with severe neurological deficits and their health care providers.
“This has great potential for restoring reliable, rapid and rich communication for somebody with locked-in syndrome who is unable to speak,” said Jose Albites Sanabria, who performed this research as a graduate student in biomedical engineering at Brown University. “That not only could provide increased interaction with their family and friends, but can provide a conduit for more thoroughly describing ongoing health issues with caregivers.”
As a neuroscientist and practicing critical care neurologist, senior author Dr. Leigh Hochberg of Brown University, Massachusetts General Hospital and the Providence VA Medical Center sees tremendous potential for the restorative capabilities of BCIs exemplified in this study.