Brain-sensing allows monkey to type at rate of 12 words per minute

In a pilot experiment conducted with monkeys, the animals equipped with brain-sensing technology were able to transcribe passages from The New York Times and Shakespeare's Hamlet at a rate of 12 English words per minute.

That technology, developed by Stanford Bio-X scientists Krishna Shenoy, a professor of electrical engineering at Stanford University, and postdoctoral fellow Paul Nuyujukian, directly reads brain signals to drive a cursor moving over a keyboard, which could provide a way for people with movement disorders to communicate.

Earlier versions of the technology have already been tested successfully in people with paralysis, but the typing was slow and imprecise. Published on Monday in IEEE, results of the latest work show improvements to the speed and accuracy of the technology that interprets brain signals and drives the cursor.

"Our results demonstrate that this interface may have great promise for use in people," Nuyujukian, who will join Stanford faculty as an assistant professor of bioengineering in 2017, was quoted as saying in a news release. "It enables a typing rate sufficient for a meaningful conversation."

The technology developed at Stanford involves a multi-electrode array implanted in the brain to directly read signals from a region that ordinarily directs hand and arm movements used to move a computer mouse. The reseachers have improved the algorithms for translating those signals and making letter selections.

"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 these high-performing algorithms developed by Nuyujukian and his colleagues, the animals could type more than three times faster than with earlier approaches.

The monkeys testing the technology had been trained to type letters corresponding to what they see on a screen.

However, the researchers noted, people using this system would likely type more slowly while they think about what they want to communicate or how to spell words. People might also be in more distracting environments and in some cases could have additional impairments that slow the ultimate communication rate.

"What we cannot quantify is the cognitive load of figuring out what words you are trying to say," Nuyujukian said.

In addition to proving the technology, the study showed that the implanted sensor could be stable for several years.

The animals had the implants used to test this and previous iterations of the technology for up to four years prior to this experiment, with no loss of performance or side effects in the animals. Endit