Neural Implant Restores Motor Function in Quadriplegia
Researchers from Battelle, a nonprofit applied science and technology development company, and The Ohio State Wexner Medical Center have developed a prototype medical system that has been able to restore complex functional movement to quadriplegic individuals. The study, led by former Batelle researcher Chad Bouton, was recently published in the journal Nature. The device, dubbed NeuroLife, was developed at Batelle, while the clinical study was conducted by neuroscientists and physicians at The Ohio State Wexner Medical Center.
Quadriplegia is a debilitating form of paralysis due to illness or injury that is characterized by the loss of use of all four limbs and torso. The degree to which motor function is lost varies greatly among individuals with quadriplegia. The loss of function depends on where the injury occurs. For example, an individual with an injury at C7 (the lowest cervical vertebra) may retain some use of the arms and hands, whereas an individual with an injury at C1 will most likely lose function from the neck down and rely upon a ventilator for respiration.
Ian Burkhart, who was paralyzed by a driving accident six years ago, is the 24-year-old pioneering participant in the study. Today, however, he is able to perform small motor tasks such as swiping a credit card or playing a guitar video game. Ian underwent implantation of a Utah microelectrode array, a device through which neural signals may be delivered, in his primary motor cortex. Subsequently he attended three training sessions weekly for 15 months, using a neural bypass system to facilitate his rehabilitation. At each session, Ian practiced using his motor cortical neuronal activity to modulate a high-resolution neuromuscular electrical stimulator (NMES). The NMES would then electrically stimulate his right forearm muscles using a custom-made flexible sleeve wrapped around his arm that contained 130 implanted electrodes. With the use of this neural bypass system, Ian was able to regain deliberate, functional movement.
Unsurprisingly, the study has attracted much attention from the media. In an interview, Burkhart described the personal significance of the study: "For me being in a wheelchair and not being able to walk is not the biggest thing, but the lack of independence because you have to rely on so many people for things. The first time I was able to open and close my hand it really gave me that sense of hope that I already had in the back of mind, but this made it more real." The device, though invasive, provides advantages over alternative electrical stimulation systems, which do not allow the degree of fine control offered by the neural bypass system.
In addition to the invasiveness of the procedure to install the device, another significant drawback of the neural bypass system is its lack of mobility. Indeed, Ian is only able to use his hands when connected to computers in the lab. Nevertheless, Rajesh Rao, director of the Center for Sensorimotor Neural Engineering at the University of Washington, believes the study marks significant progress in the field and is optimistic: “It’s quite impressive what they’ve shown, this sequence of movements to pick up and pour something and pick up a stirrer — it’s an advance toward a goal we all have, to provide as much independence to these patients as possible,” The neural bypass system holds promise for helping to restore motor function to patients affected by a variety of brain and spinal cord injuries, though there is much work to be done before the system can confer proper mobile independence.