The device, known as a brain-computer interface, allowed the patients to write emails and texts, browse the web and perform everyday tasks like online shopping and banking. One of the patients, 62-year-old Philip O'Keefe, even used the device to compose a tweet that read "Hello, world!" in December. The results from the study, which was conducted in Australia, were announced Tuesday and will be presented in April at the American Academy of Neurology's annual meeting in Seattle.
The University of Pittsburgh Medical Center and Mount Sinai Hospital in New York will participate in the first U.S. clinical trial to test the device, made by New York City-based company Synchron.
"An easy way to think about a brain-computer interface is as a substitute for the finger keyboard interactions that we typically use when we are interacting with our computers," said Douglas Weber, a professor of mechanical engineering at CMU and an author on the study. Mr. Weber has advised Synchron on the development of the device. "If you're paralyzed and you don't have the ability to use your fingers, you need alternatives to do that."
Voice recognition is one alternative, but not all devices and apps have voice recognition, and some paralyzed people have lost the use of their voice. Eye-tracking technology is currently the only option for those patients. A brain-computer interface could provide a more seamless way for paralyzed people to communicate and use a computer.
The brain implant in Synchron's study is about the size of a matchstick. Dubbed the Stentrode, it resembles a heart stent — a mesh device used to treat heart disease by propping open clogged arteries. The Stentrode is delivered to a patient's brain using a thin catheter that's snaked through the jugular vein in the neck. It stays inside that blood vessel, traveling all the way to the motor cortex, the part of the brain that directs the body's movement.
Using 16 sensors that dot its surface, the implant collects brain signals from the motor cortex. These signals are sent to a second device, which is implanted in the chest. It then translates the brain signals into commands for controlling a laptop computer.
"In spite of muscles that are paralyzed, the actions that those muscles are trying to convey can be routed out through signals in the brain," Mr. Weber said. "Our thoughts drive the actions of our muscles and in the absence of muscles that work, those messages can be conveyed through sensors that are placed in or around the brain to pick up those messages."
The Australian study participants were all paralyzed from amyotrophic lateral sclerosis, or Lou Gehrig's disease, a neurodegenerative condition that gradually damages the nerve cells in the brain and spinal cord. Five patients were initially evaluated for the trial, but one was excluded for medical reasons. Four patients ultimately received the device, and researchers monitored them for a year. They found that the device stayed in place and was safe with no major adverse side effects.
For the U.S. trial, UPMC is aiming to enroll an initial three patients with quadriparesis, or paralysis in all four of the limbs, beginning this fall. CMU researchers will work with Synchron on machine learning methods for decoding patients' brain signals to better interpret their intended actions.
"This is really a life-changing opportunity for these patients," said Dr. David Lacomis, the co-principal investigator of the UPMC trial and a professor of neurology and pathology at Pitt. He said not only could this technology improve the quality of life for people with paralysis but also reduce caregiver burden.
Researchers have been developing brain-computer interfaces for decades to help people with paralysis control computers or other devices, such as robotic arms. Other interfaces require drilling into the skull to place the implant. Many also have clunky setups with external wires that protrude from the patient's head. By contrast, the Stentrode device is inserted through a small incision in the neck. It's also wireless and fully implantable.
Dr. Peter Konrad, interim chair of neurosurgery at West Virginia University Medicine, who wasn't involved in the Synchron research, said the study represents a "novel tactic in getting a large number of electrical probes into close proximity to brain circuits in patients who are paralyzed."
He said the study demonstrates that the implant can be safely placed in humans for at least a year. However, he noted that the study was not set up to determine how well this type of implant allowed subjects to operate a computer compared to other types of brain-computer interfaces.
"Yet the ease with which [the] implants are able to be inserted and the safety of this technology is breaking barriers for the five million plus paralyzed patients who desperately need a solution," Dr. Konrad said.
The device will likely need to go through several more years of testing before it can be approved by the Food and Drug Administration and available commercially.
Eventually, brain-computer interfaces could help paralyzed people operate a smart home, said Dr. Lacomis. "Someone could turn on their own lights, turn on their own TV, change the channels, turn on the stereo and use robotic arms. All sorts of things could be done with this technology."
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