A research team at UC Davis and UC Davis Health has demonstrated that brain-computer interfaces (BCIs) designed to translate brain signals into speech can also allow users to control a computer cursor. The study, published in the Journal of Neuroengineering, was funded by the National Science Foundation and the National Institutes of Health.
The research was led by the UC Davis Neuroprosthetics Lab, co-directed by neuroscientist Sergey Stavisky and neurosurgeon David Brandman. The lab had previously developed a highly accurate BCI for speech, and this new project builds on that work.
“Future steps in multimodal BCIs could include gesture decoding for all sorts of different things, enriching the types of interactions someone with paralysis can have with their environment beyond speech,” said Tyler Singer-Clark, a biomedical engineering Ph.D. student and first author of the paper.
The BCI, which is implanted in the speech motor cortex, interprets electrical activity generated by thought and converts it into words displayed on a computer. The team observed that the brain region used for speech in their BCI also showed potential for controlling a cursor, a function usually linked to a different area of the brain.
Singer-Clark developed cursor control software for the speech BCI, drawing on previous research and the lab’s existing codebase. “We didn’t have to reinvent the pre-processing of the neural data,” he said. “For cursor control, it’s actually the same pre-processing steps the speech BCI uses to get the neural features that are going to be useful for decoding the intention of the participant.”
The research involved a participant in the BrainGate clinical trial who has amyotrophic lateral sclerosis (ALS) and is unable to move. Singer-Clark observed the participant’s neural activity as he watched and thought about moving a cursor on a screen. This data was then used to individualize the cursor control software.
Once enabled, the participant adapted to the cursor control in less than 40 seconds, using thought to move the cursor, click on apps, and open links on his computer. Singer-Clark explained that the BCI does not translate abstract thoughts into movement, but works more like intuition. “That’s his word, intuition,” Singer-Clark said. “I’ll say, ‘What motor imagery are you using?’ And he says, ‘Intuition.’”
Brandman commented on the significance of the work: “Singer-Clark’s work is incredibly important for the field. His work has not only empowered our BrainGate2 participant to use a computer cursor with his thoughts but has also led the way for multiple companies in this space to design their clinical trials.”
The research suggests that complex, multimodal BCIs are possible and that different body parts and their movements may be represented in multiple areas of the motor cortex, rather than being isolated to specific regions.
Singer-Clark noted the personal impact of the project: “There’s a man with ALS who can control his computer independently without someone else helping him for hours and hours every day. It’s like this great event, and we might not have tried if we didn’t have that prior research encouraging us to do that.”
The UC Davis team continues to pursue technology that could restore greater autonomy to people with paralysis.
