A new study published in Nature Neuroscience describes an investigational brain computer interface (iBCI) typing neuroprosthesis that can help restore communication for patients with paralysis, according to a March 16 announcement from Mass General Brigham Neuroscience Institute and Brown University. The device was tested in two participants enrolled in the BrainGate clinical trial—one with amyotrophic lateral sclerosis (ALS) and another with a cervical spinal cord injury.
The development of this iBCI typing neuroprosthesis addresses a significant challenge faced by people who lose both speech and hand function due to paralysis. Many existing communication devices, such as eye-gaze technology, are slow and can be frustrating for users. "For many people with paralysis, when losing use of both the hands and the muscles of speech, communication can become difficult or impossible. Often, people with severe speech and motor impairments end up relying on things like eye-gaze technology-spelling words out one letter at a time by using an eye movement tracking system. Those systems take far too long for many users," said Daniel Rubin, MD, PhD, senior author of the study and critical care neurologist at Mass General Brigham Neuroscience Institute. "Patients often find this and other types of Augmentative and Alternative Communication systems frustrating to use. BCIs are on track to become an important new alternative to what's currently offered."
The BrainGate team consists of experts from various fields working together to improve tools for those affected by neurological disease or injury. "Since 2004, our BrainGate team has been advancing and testing the feasibility and efficacy of implantable brain computer interfaces to restore communication and independence for people with paralysis," said Leigh Hochberg, MD, PhD, co-author of the study and director of the Center for Neurotechnology and Neurorecovery at Mass General Brigham Neuroscience Institute. "The BrainGate consortium demonstrates the strength of academic and university-based researchers working together, thinking about what's possible, and then advancing the frontiers of restorative neurotechnology. And by doing so, we make it that much easier for industry to create the final form of implantable medical devices for our patients."
The iBCI system uses microelectrode sensors implanted in the motor cortex—the part of the brain responsible for movement—and maps attempted finger movements onto a QWERTY keyboard displayed before participants. As users attempt these movements mentally, electrodes detect neural activity which is then translated into letters through a computer system enhanced by predictive language modeling.
In trials conducted at participants' homes, one individual achieved a top typing speed equivalent to 22 words per minute with high accuracy—a rate comparable to able-bodied typists—after calibrating their device using just 30 sentences.
"Decoding these finger movements is also a big step toward being able to restore complex reach and grasp movements for people with upper extremity paralysis," said Justin Jude, PhD, first author on the paper from Mass General Brigham. "And there's also room to make this communication tool better-like implementing a stenography or otherwise personalized keyboard to make typing even faster. Our BCI is a great example of how modern neuroscience and artificial intelligence technology can combine to create something capable of restoring communication and independence for people with paralysis."
