Date January 13, 2023
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Clinical trials show encouraging safety profile for brain-computer interface turning thoughts into action

In an important step toward a medical technology that could help restore independence of people with paralysis, researchers find the investigational BrainGate neural interface system has low rates of associated adverse events.

PROVIDENCE, R.I. [Brown University] — More than two decades ago, a team of Brown University researchers set out with an ambitious goal to provide people with paralysis a revolutionary neurotechnology capable of turning thoughts about movement into actual action, using a tiny device that would one day be implanted in the surface of the brain. Their work led to an ongoing, multi-institution effort to create the BrainGate brain-computer interface, designed to allow clinical trial participants with paralysis to control assistive devices like computers or robotic limbs just by thinking about the action they want to initiate.

Now, after decades of advancements, researchers are getting their best glimpse yet at the safety profile for this promising technology and what it means for long-term use by people affected by neurologic disease or paralysis.

Published on Friday, January 13, in Neurology, the team’s new study analyzes more than 17 years of safety data on clinical trials testing the BrainGate technology. The study found a low rate of adverse events associated with the implanted brain-computer interfaces (BCIs) and concluded that the technology should continue to be evaluated for its potential to help people with paralysis regain lost neurologic function.

“In the largest ongoing trial of intracortical brain-computer interfaces, the interim safety profile reported today supports the possibility that these systems may become restorative neurotechnologies for people with paralysis,” said Dr. Leigh R. Hochberg, an engineering and brain science professor at Brown, a critical care neurologist at Massachusetts General Hospital, and director of the BrainGate academic consortium leading the development and testing of the technology.

The new study, which includes a number of Brown authors, is an important step for the BrainGate consortium and other BCI research as the current BrainGate clinical trial enters its 14th year.

“Intracortical brain-computer interfaces have so much promise for restoring communication and mobility,” said Hochberg, who also directs the V.A. Rehabilitation Research and Development Center for Neurorestoration and Neurotechnology in Providence. “Translating these advances in neural engineering to patient care will depend largely on whether the devices are accompanied by an acceptably low degree of risk.”

The BrainGate device is a type of BCI that is implanted in a part of the brain that controls limb movement. The microelectrode array — called a “Utah” array — is smaller than a contact lens and is placed into the surface of the motor cortex. It works by detecting neural signals associated with intended movements, sending them out to a small nearby computer that then uses algorithms to translate the signals into movement commands.

The ultimate goal of BrainGate is to restore communication, mobility and independence for people with tetraplegia. Previous studies by BrainGate researchers have shown that the BCI can enable people to move robotic arms or even move their own paralyzed arm and hand.

“ In the largest ongoing trial of intracortical brain-computer interfaces, the interim safety profile reported today supports the possibility that these systems may become restorative neurotechnologies for people with paralysis. ”

Dr. Leigh R. Hochberg Professor of engineering and brain science

The new BrainGate study evaluated a total of 12,203 days of safety data from 14 clinical trial participants with quadriparesis resulting from spinal cord injury, brainstem stroke or ALS. Participants were ages 18 to 75 and were enrolled in BrainGate’s trials between 2004 to 2021. In that span, the study found, there were 68 device-related adverse events — the most common was skin irritation around the small portion of the device on top of a user’s head that connects the neural sensor array implanted in the brain to the nearby neural decoding system.

There were six serious adverse events determined to be related to the BrainGate device or surgical procedure. Two participants, both of whom had a history of traumatic brain injury, had brief post-operative seizures, which were easily treated. The researchers said none of the adverse events documented in the study were unanticipated, resulted in permanently increased disability, required removal of the device or led to infections in the nervous system.

Data from the clinical trials came from seven sites across the U.S., including Mass General and the Providence V.A. Researchers at Mass General led the study in collaboration with colleagues from Brown, the V.A., Stanford University, and several other institutions in the consortium. The scientists wrote in the study that while the safety profile is a big step forward, there is still much work to be done to reach their ultimate goals for the technology.

“Overall, we are reassured by our findings over the past 17 years that the investigational BrainGate Neural Interface system is being deployed safely,” the researchers wrote. “Both our group and others continue to work on components and systems that would permit [BCIs] to become fully implanted, available to users around-the-clock, and incorporating a suite of design characteristics previously proposed.”

BrainGate’s history at Brown

BrainGate grew out of fundamental research happening in the lab of Brown professor John Donoghue in the late 1990s and early 2000s. While the ongoing clinical trials are being led by the broader BrainGate consortium, researchers at Brown remain key collaborators in engineering and neuroscientific leadership, and have been integral parts of major technological developments.

The list of their advances over the years is extensive. For example, Donoghue and other Brown researchers helped spur BrainGate initially by showing in fundamental research that signals from the brain that normally control hand movement could be decoded and used to control a computer cursor. They were also part of the team that introduced the BCI to the wider public in a 2006 paper in Nature that showed how people with paralysis could control a cursor on a computer screen using the brain-implanted device.

In 2012, the Brown-based team published landmark research in which clinical trial participants were able to operate robotic or prosthetic arms and hands using the BrainGate interface. That work was followed by refinements to the system, new clinical breakthroughs that enabled people to type on computers, use tablet apps and even move their own paralyzed limbs.

“When we set out in the ’90s, this is exactly the path we said we wanted to follow,” said Donoghue, one of the leaders of the BrainGate consortium and a professor of neuroscience at Brown. “These have been giant landmarks: people controlling a computer, people controlling a robotic arm and a person controlling their own arm with their thoughts through BrainGate.”

Just last year, BrainGate went wireless, eliminating the need for cables to connect the sensing array in the brain to the computer that decodes the neural signals.

“In the future, I hope that BrainGate becomes an option for everyone with paralysis,” Donoghue said. “The golden day would be when somebody who is paralyzed gets a BrainGate-like system implanted, and they go play basketball.”

The new study in Neurology was supported with funding from the U.S. Department of Veterans Affairs; the National Institutes of Health; Howard Hughes Medical Institute; Massachusetts General Hospital; the Carney Institute for Brain Science at Brown University; and several additional funders noted in the paper.

CAUTION: Investigational device. Limited by federal law to investigational use.