Scientists trying to convert paralyzed people's brain activity into text

CHICAGO, May 12 (Xinhua) -- Scientists have developed a brain-computer interface (BCI) designed to restore the ability to communicate in people with spinal cord injuries and neurological disorders such as amyotrophic lateral sclerosis (ALS), according to a news release of the National Institutes of Health (NIH) on Wednesday.

When a person becomes paralyzed due to spinal cord injury, the part of his brain that controls movement still works. Under this pretext, the researchers focused on the part of the brain that is responsible for fine movement.

The participant was asked to copy letters that were displayed on the screen, which included the 26 lower-case letters along with some punctuation. At the same time, implanted electrodes recorded the brain activity from approximately 200 individual neurons that responded differently while he mentally "wrote" each individual character. After a series of training sessions, the BCI's computer algorithms learned how to recognize neural patterns corresponding to individual letters, allowing the participant to "write" new sentences that hadn't been printed out before, with the computer displaying the letters in real time.

Using this system, the participant was able to compose sentences and communicate with others at a speed of about 90 characters per minute, comparable to someone of a similar age typing on a smartphone.

Similar BCI systems have been developed to restore motor function through devices like robotic arms before. But in contrast, "point-and-click" interfaces have only achieved about 40 characters per minute.

"This method is a marked improvement over existing communication BCIs that rely on using the brain to move a cursor to "type" words on a screen," said Frank Willett, a research scientist at Stanford University and the study's lead author. "Attempting to write each letter produces a unique pattern of activity in the brain, making it easier for the computer to identify what is being written with much greater accuracy and speed."

The clinical trial, called BrainGate2, is testing the safety of BCIs that directly connect a person's brain to a computer.

In the future, the research team intends to test the system on a patient who has lost the ability to speak, such as someone with advanced ALS. In addition, they are looking to increase the number of characters available to the participants.

The study has been published in Nature.