Kochevar (56) , was paralyzed below his shoulders in a bicycling accident , is believed to be the first person with quadriplegia in the world to have arm and hand movements restored with the help of two temporarily implanted technologies.
A brain-computer interface with recording electrodes under his skull, and a functional electrical stimulation (FES) system activating his arm and hand, reconnect his brain to paralyzed muscles. “For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me,” said Kochevar, 56, of Cleveland. “It’s better than I thought it would be.”
Kochevar is the focal point of research led by Case Western Reserve University, the Cleveland Functional Electrical Stimulation (FES) Center at the Louis Stokes Cleveland VA Medical Center and University Hospitals Cleveland Medical Center (UH). “He’s really breaking ground for the spinal cord injury community,” said Bob Kirsch, chair of Case Western Reserve’s Department of Biomedical Engineering, executive director of the FES Center and principal investigator (PI) and senior author of the research. “This is a major step toward restoring some independence.”
People with quadriplegia say their first priority is to scratch an itch, feed themselves or perform other simple functions with their arm and hand, instead of relying on caregivers. “By taking the brain signals generated when Bill attempts to move, and using them to control the stimulation of his arm and hand, he was able to perform personal functions that were important to him,” said Bolu Ajiboye, assistant professor of biomedical engineering and lead study author.
The research with Kochevar is part of the ongoing BrainGate2 pilot clinical trial, conducted by a consortium of academic and VA institutions assessing the safety and feasibility of the implanted brain-computer interface (BCI) system in people with paralysis. Other investigational BrainGate research has shown that people with paralysis can control a cursor on a computer screen or a robotic arm.
Implanting electrode arrays
Jonathan Miller, assistant professor of neurosurgery at Case Western Reserve School of Medicine and director of the Functional and Restorative Neurosurgery Center at UH, led a team of surgeons who implanted two 96-channel electrode arrays—each about the size of a baby aspirin—in Kochevar’s motor cortex, on the surface of the brain.
The arrays record brain signals created when Kochevar imagines movement of his own arm and hand. The brain-computer interface extracts information from the brain signals about what movements he intends to make, then passes the information to command the electrical stimulation system.
To prepare him to use his arm again, Kochevar first learned how to use his brain signals to move a virtual-reality arm on a computer screen. As Kochevar’s ability to move the virtual arm improved through four months of training, the researchers believed he would be capable of controlling his own arm and hand. Miller then led a team that implanted the FES systems’ 36 electrodes that animate muscles in the upper and lower arm.
Eight years of muscle atrophy required rehabilitation. The researchers exercised Kochevar’s arm and hand with cyclical electrical stimulation patterns. Over 45 weeks, his strength, range of motion and endurance improved. As he practiced movements, the researchers adjusted stimulation patterns to further his abilities.
Moving by thinking
Kochevar can make each joint in his right arm move individually. Or, just by thinking about a task such as feeding himself or getting a drink, the muscles are activated in a coordinated fashion. When asked to describe how he commanded the arm movements, Kochevar told investigators, “I’m making it move without having to really concentrate hard at it…I just think ‘out’…and it goes.”
Advances needed to make the combined technology usable outside of a lab are not far from reality, the researchers say. Work is underway to make the brain implant wireless, and the investigators are improving decoding and stimulation patterns needed to make movements more precise. Fully implantable FES systems have already been developed and are also being tested in separate clinical research.
A report in the Lancet concerning the research is the result of a long-running collaboration between Kirsch, Ajiboye and the multi-institutional BrainGate consortium. Leigh Hochberg, MD, PhD, a neurologist and neuroengineer at Massachusetts General Hospital, Brown University and the VA RR&D Center for Neurorestoration and Neurotechnology in Providence, Rhode Island, directs the pilot clinical trial of the BrainGate system and is a study co-author.