PROVIDENCE, R.I. [Brown University] — Scientists with the BrainGate research collaborative have reached a major milestone in restoring speech for people who have lost the ability to speak due to paralysis.
In a new study published in Nature, the researchers describe using sensors implanted in areas of the cerebral cortex associated with speech to accurately turn the brain activity of a patient with ALS who lost the ability to speak into words on a screen just by the patient thinking of saying them.
The clinical trial participant — who can no longer use the muscles of her lips, tongue, larynx and jaws to enunciate units of sound clearly — was able to generate 62 words per minute on a computer screen simply by attempting to speak. This is more than three times as fast as the previous record for assisted communication using implanted brain-computer interfaces (BCIs) and begins to approach the roughly 160-word-per-minute rate of natural conversation among English speakers.
The study, published on Wednesday, Aug. 23, shows that it’s possible to use neural activity to decode attempted speaking movements with better speed and a larger vocabulary than what was previously possible.
“This is a scientific proof of concept, not an actual device people can use in everyday life,” said Frank Willett, one of the study’s lead authors and a research scientist at Stanford University and the Howard Hughes Medical Institute. “It’s a big advance toward restoring rapid communication to people with paralysis who can’t speak.”
The work is part of the BrainGate clinical trial, directed by Dr. Leigh Hochberg, a critical care neurologist and a professor at Brown University’s School of Engineering who is affiliated with the University’s Carney Institute for Brain Science. Dr. Jaimie Henderson, a professor of neurosurgery at Stanford, and Krishna Shenoy, a Stanford professor and HHMI investigator, who died before the study was published, were also authors on the study.
The study is the latest in a series of advances in brain-computer interfaces made by the BrainGate consortium, which along with other work using BCIs has been developing systems that enable people to generate text through direct brain control for several years. Previous incarnations have involved trial participants thinking about the motions involved in pointing to and clicking letters on a virtual keyboard, and, in 2021, converting a paralyzed person’s imagined handwriting onto text on a screen, attaining a speed of 18 words per minute.
“With credit and thanks to the extraordinary people with tetraplegia who enroll in the BrainGate clinical trials and other BCI research, we continue to see the incredible potential of implanted brain-computer interfaces to restore communication and mobility,” said Hochberg, who in addition to his roles at Brown is a neurologist at Massachusetts General Hospital and director of the V.A. Rehabilitation Research and Development Center for Neurorestoration and Neurotechnology in Providence.
One of those extraordinary people is Pat Bennett, who having learned about the 2021 work, volunteered for the BrainGate clinical trial that year.