Composing thoughts: mental handwriting produces brain activity that can be turned into text

The study, published in Nature, was funded by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies® (BRAIN) Initiative as well as the National Institute of Neurological Disorders and Stroke (NINDS) and the National Institute on Deafness and Other Communication Disorders (NIDCD), both part of the NIH.

Researchers focused on the part of the brain that is responsible for fine movement and recorded the signals generated when the participant attempted to write individual letters by hand. In doing so, the participant, who is paralyzed from the neck down following a spinal cord injury, trained a machine learning computer algorithm to identify neural patterns representing individual letters. While demonstrated as a proof of concept in one patient so far, this system appears to be more accurate and more efficient than existing communication BCIs and could help people with paralysis rapidly type without needing to use their hands. 

“This study represents an important milestone in the development of BCIs and machine learning technologies that are unraveling how the human brain controls processes as complex as communication,” said John Ngai, Ph.D., director of the NIH BRAIN Initiative. “This knowledge is providing a critical foundation for improving the lives of others with neurological injuries and disorders.”

When a person becomes paralyzed due to spinal cord injury, the part of the brain that controls movement still works. This means that, while the participant could not move his hand or arm to write, his brain still produced similar signals related to the intended movement. Similar BCI systems have been developed to restore motor function through devices like robotic arms.

“Just think about how much of your day is spent on a computer or communicating with another person,” said study co-author Krishna Shenoy, Ph.D., a Howard Hughes Medical Institute (HHMI) Investigator and the Hong Seh and Vivian W. M. Lim Professor at Stanford University. “Restoring the ability of people who have lost their independence to interact with computers and others is extremely important, and that is what is bringing projects like this one front and center.”