By Emily Waltz
The ancient art of handwriting has just pushed the field of brain-computer interface (BCI) to the next level. Researchers have devised a system that allows a person to communicate directly with a computer from his brain by imagining creating handwritten messages. The approach enables communication at a rate more than twice as fast as previous typing-by-brain experiments.
Researchers at Stanford University performed the study on a 65-year-old man with a spinal cord injury who had had an electrode array implanted in his brain. The scientists described the experiment recently in the journal Nature.
“The big news from this paper is the very high speed,” says Cynthia Chestek, a biomedical engineer at the University of Michigan, who was not involved in the study. “It’s at least half way to able-bodied typing speed, and that’s why this paper is in Nature.”
For years, researchers have been experimenting with ways to enable people to directly communicate with computers using only their thoughts, without verbal commands, hand movement, or eye movement. This kind of technology offers a life-giving communication method for people who are “locked in” from brainstem stroke or disease, and unable to speak.
Successful BCI typing-by-brain approaches so far typically involve a person imagining moving a cursor around a digital keyboard to select letters. Meanwhile, electrodes record brain activity, and machine learning algorithms decipher the patterns associated with those thoughts, translating them into the typed words. The fastest of these previous typing-by-brain experiments allowed people to type about 40 characters, or 8 words, per minute.
That we can do this at all is impressive, but in real life that speed of communication is quite slow. The Stanford researchers were able to more than double that speed with a system that decodes brain activity associated with handwriting.
In the new system, the participant, who had been paralyzed for about a decade, imagines the hand movements he would make to write sentences. “We ask him to actually try to write—to try to make his hand move again, and he reports this somatosensory illusion of actually feeling like his hand is moving,” says Frank Willett, a researcher at Stanford who collaborated on the experiment.
A microelectrode array implanted in the motor cortex of the participant’s brain records the electrical activity of individual neurons as he tries to write. “He hasn’t moved his hand or tried to write in more than ten years and we still got these beautiful patterns of neural activity,” says Willett.
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