Brain-sensing tech helps people with movement disorders communicate via text

How many monkeys does it take to type a passage of Shakespeare? One monkey, equipped with brain-sensing technology.

Developed by scientists at Stanford University, the technology can directly read brain signals to drive a cursor moving over a keyboard. In an experiment with monkeys, the primates were able to transcribe passages from Hamlet and The New York Times at a rate of 12 words per minute. Earlier versions of the technology were successfully tested in people with paralysis, but the typing was slow and imprecise.

The latest study tests improvements to the speed and accuracy of the technology that interprets brain signals and drives the cursor. 

Postdoctoral fellow in Stanford’s Department of Neurosurgery, Paul Nuyujukian and his colleagues developed the brain-sensing technology. Image source: Stanford University.

“Our results demonstrate that this interface may have great promise for use in people,” said postdoctoral fellow in Stanford’s Department of Neurosurgery, Paul Nuyujukian. “It enables a typing rate sufficient for a meaningful conversation.”

Alternative approaches for helping people with movement disorders include track eye movements, or in the case of Stephen Hawking, tracking movements of individual muscles in the face. Though helpful, these options come with limitations, often requiring a degree of muscle control that might be difficult for some people. Directly reading brain signals could overcome some of these challenges and provide a way for people to communicate their thoughts and emotions.

The Stanford team’s technology involves a multi-electrode array implanted in the brain to directly read signals from a region that typically directs hand and arm movements used to move a computer mouse. It’s the algorithms used for translating the signals and making better letter selections that the scientists have been improving upon.

“The interface we tested is exactly what a human would use,” Nuyujukian said. “What we had never quantified before was the typing rate that could be achieved.” Using the high-performing algorithms developed by Nuyujukian and his colleagues, the animals could type more than three times faster compared to earlier approaches.

According to the researchers, people using this system would likely type slow while thinking about how to spell words or what they wish to communicate. Despite that, Nuyujukian said that even a rate lower than the 12 words per minute achieved by monkeys would be a significant advance for people who aren’t otherwise able to communicate effectively.

“Understand that we’re not using auto-completion here like your smartphone does where it guesses your words for you,” Nuyujukian said. Eventually the technology could be paired with the technology used by smartphones or tablets to improve typing speeds.

The results of the study were published in IEE.