Scientific breakthroughs in brain-computer interface technology may offer new hope for overcoming paralysis.
In the latest advance, a man with quadriplegia who was paralyzed eight years ago, regained functional movement of his arm.
He fed himself with his hand using this technology, a first in medical history.
Researchers at Case Western Reserve University in Ohio announced their findings on Mar. 28 in the British medical journal The Lancet.
The Case Western announcement was made the day after entrepreneur Elon Musk (of the Tesla electric car and rocket company SpaceX) revealed plans to develop a similar technology.
Musk’s “neural lace,” according to a report in The Wall Street Journal, would link a person’s brain directly with a computer.
Meanwhile, scientists at The Ohio State University (OSU) are working with a patient with paralysis and have developed a technology similar to the one at Case Western.
The OSU team is developing the technology with scientists at Battelle Memorial Institute, a nonprofit organization in Ohio that creates medical devices.
Decoding brain signals
The Case Western scientists have been working with Bill Kochevar, a 53-year-old with quadriplegia who was injured in a bicycle accident.
The researchers implanted a neuroprosthesis that decoded his brain signals and transmitted them to sensors in his arm, which helped him to regain movement in his hand and arm.
Robert Kirsch, PhD, chair of the Case Western Department of Biomedical Engineering, executive director of the university’s Functional Electrical Stimulation (FES) Center, is senior author of the research.
He called the breakthrough a major step.
“We’ve shown the feasibility of recording someone’s movement intentions and then making their own arm make those movements,” he said.
Kirsch’s colleague Bolu Ajiboye, PhD, an assistant professor of biomedical engineering at Case Western, and research associate at the Louis Stokes Cleveland Veterans Administration Medical Center, explained how the technology works.
“Normal movement in unimpaired persons occurs because the motor cortex generates a movement command, represented as electrical signals, that is passed through the spinal cord, and then activates the appropriate muscles,” Ajiboye told Healthline.
A spinal cord injury prevents those electrical impulses from reaching the muscles, he explained, but the original movement command is still properly coded in the brain's patterns of electrical activity.
“Our system records the pattern of electrical activity through the brain implant and uses mathematical algorithms to decode it into a movement command that is intended by the person with paralysis. That command is converted into an electrical stimulation pattern that is applied to the right group of muscles to produce the movement. To Mr. Kochevar, the process is seamless and invisible. In his words, he says he just thinks about moving his arm and the arm moves as he intends.”
Ajiboye also pointed out what this new technology isn’t.
Science has attempted many times to “fix” a damaged spine through tissue engineering and regrowth without success, he said.
“We would love for scientists to find a way to regrow and reconnect the spinal cord using cell therapies,” Ajiboye said. “However, our current approach uses technology to circumvent the spinal injury to get the movement signals from the brain to the right set of muscles to produce the movement.”
Other technologies that help people with paralysis to regain function are typically limited to devices they can control using their voices and eye movements, or by moving their heads.
However, none of these devices allow for control of one’s own limb.
“Our device allows a user to move his own limb just by thinking,” Ajiboye explained. “I want to make it clear that our system is circumventing spinal injury, rather than reversing paralysis. Without the system, the user would still be paralyzed, and there is no evidence to suggest that use of this system would eventually result in the spinal regrowth, or would reintroduce the ability to move without the system.”
How the technology works
Why is the Case Western technology unique?
The system is the first to use both a brain-implant computer interface with an FES system to electrically activate paralyzed muscles.
Prior to this, scientists have treated a number of people with paralysis but with only one approach or the other.
Kochevar is the first person to experience this combined technology.
Ajiboye said many research groups have used the brain interface system with humans and with nonhuman primates. Both test groups were able to perform tasks such as moving cursors on a computer screen or moving robotic arms.
“Our FES Center for the last 25 to 30 years has implanted FES systems in people with spinal cord injuries to restore a number of functions, including standing, walking, breathing, and hand and arm movements,” he said.
Kochevar joined the Case Western research project in 2014. He received his brain implants in December of that year. In 2015, Kirsch, Ajiboye, and their colleagues implanted electrodes in the muscles of his arm and hand.
Kochevar learned to activate his brain signals to control different devices.
“We first had him watch a virtual arm move on a computer screen, while he simultaneously imagined making the same movements with his own arm,” Ajiboye said. “This generated patterns of neural activity. We then developed a neural decoder, a mathematical algorithm that related the generated patterns of neural activity with aspects of the virtual arm movements.”
Next, they had Kochevar control the virtual arm by generating patterns of brain signals that were then interpreted by the neural decoder, Ajiboye said.
Kochevar trained to move the virtual arm with precision to specified targets in the workspace. The scientists quantified his brain control of the virtual arm, and discovered that he was able to control it almost immediately, Ajiboye said. In addition, Kochevar relatively quickly achieved a success rate of 95 to 100 percent of target accuracy.
Finally, the scientists had Kochevar attempt to move his arm through FES stimulation in a two-step process.
“We manually moved his arm (via electrical stimulation) and instructed him to imagine that he was in control of his arm movements,” Ajiboye said. “Again, this helped generate the desired patterns of neural activity, which we used to build and refine our neural decoder. We had him use the final neural decoder to command the movements of his own arm, reanimated through electrical stimulation. He was able to instantly move his arm as desired, and has progressively gotten better with increased use.”
In a video released by Case Western, Kochevar said, “It was amazing because I thought about moving my arm and it did. I could move it in and out, up and down.”
Since Kochevar had long-term paralysis, his muscles were initially weak and easily fatigued. Ajiboye said.
To build his muscle strength and resistance to fatigue, the team “exercised” his muscles for several hours a day using electrical stimulation without the brain interface system.
Over time, this electrically stimulated exercise increased his muscle strength and his ability to use the system longer without fatigue.
Like the Case Western innovations, the Ohio State innovation helped a man with quadriplegia to use his hand after years of paralysis.
The research team was led by Dr. Ali Rezai, a professor of neurosurgery and neuroscience, and director of the Center for Neuromodulation at the university’s Wexner Medical Center.
The patient, Ian Burkhart, sustained a severe spinal cord injury at age 19 during a diving accident. It left him with little function and movement in his shoulders and biceps, and no movement from his elbows to his hands.
“Our team has developed a brain-computer interface technology that bypasses the damaged spinal cord, allowing a patient such as Ian with spinal cord injury and quadriplegia and no function of his hands for five years to simply use his thoughts to move his lifeless hand to come alive and under his volitional control,” Rezai told Healthline.
In April 2014, Rezai implanted a microchip the size of the head of a pencil eraser on the surface of the motor cortex of Burkhart’s brain. The chip’s 96 microelectrodes recorded the firing of his individual neurons.
Rezai and his colleagues developed the neural bypass system, which records and analyzes the brain activity that occurs when Burkhart intends to move his hand.
After bypassing the damaged spinal cord and damaged connection from the brain to the muscle nerves, the system links Burkhart’s brain signal with an external garment sleeve, Rezai said.
This enables Burkhart to move his hand.
“The brain implant records and interprets brain signals linked to thoughts, and links them to an external wearable sleeve garment to control his muscles,” Rezai explained. “It’s a neuromuscular stimulation system. The thoughts associated with an intention to move — for example opening the hand — are linked and connected within milliseconds to actual functional hand movement.”
The first generation of the external wearable sleeve garment and stimulation system, he said, has up to 160 stimulating electrodes “made up of super flexible hydrogel — a high-definition, high-resolution array of electrodes that conform to different shapes and contours such as the forearm.”
The garment can be shaped into a sleeve, a glove, a sock, pants, belt, head-band, and other form factors.
“Significant complexity and coordination is needed to allow movements in a smooth fashion to pick up a stirrer to stir the coffee, use a toothbrush, or play a video game,” he said. “This machine learning algorithm is improving and refining the movements from rough and choppy movements, to more smooth and fluid movements.”
Optimism for the future
Neuroscientists observing the recent breakthroughs are impressed and optimistic.
Joseph O’Doherty, PhD, a senior postdoctoral fellow at the Philip Sabes Lab at the University of California, San Francisco, Center for Integrative Neuroscience, calls these recent advances in brain-computer interface technology “groundbreaking.”
“This research shows that paralyzed limbs can be reanimated — by thought alone — for restoring the coordinated, multi-joint movements important for daily life: reaching, grasping, eating, and drinking,” he told Healthline. “It is a proof-of-principle demonstration that raises the possibility that similar therapies could soon find adoption outside of the clinic.”
Scientists have been working on brain-computer interfaces, in some form or another, since the late 1960s, he said. The field has progressed from the control of computer cursors, to moving wheelchairs and robotic arms, to, now, reestablishing voluntary control over the limbs.
“Spinal cord injury often impairs the sense of touch as well as the ability to move,” O’Doherty said. “Restoring limb sensations will be a crucial element of neuroprostheses that permit fluid and natural movements.”
“There are still many challenges to overcome,” he added, “but this new result, combined with many related advances in wireless technology, battery technology, materials science, and more, makes me very optimistic about neuroprosthetic devices for restoring movement and sensation becoming widely available.”
Rezai said 12,000 individuals in the United States each year sustain a spinal cord injury, and 300,000 live with such injuries from motor vehicle accidents, trauma, sports injuries, and falls.
Less than 1 percent achieve full recovery, and most have deficits that rely on various assistive and adaptive technologies to provide a limited degree of independence.
“These innovations offer hope and the potential for movement restoration and increased independence to many patients living with paralysis or other physical disabilities,” Rezai said. “In addition to motor improvements, this technology has potential implications for those with sensory deficits, chronic pain, speech, stroke, cognitive, anxiety, and behavioral implications.”
Rezai said he is hopeful that soon those with physical, sensory, cognitive, and other disabilities will have the opportunity to be more functional, to have more independence, and a better quality of life.
“Our goal is to make this technology less invasive, reduce the size of the device, miniaturize the sensors, make the system wireless, and provide the system at home instead of in the laboratory,” he said.
The Case Western team is also working to advance its system technologically.
“We need to develop a wireless brain interface to replace the cable that connects the user to a set of recording computers,” Ajiboye said. “We need to enhance the brain implant for longevity, to increase the number of neurons we can record from, and to develop a fully implanted brain interface and functional electrical stimulation system.”