Millions of people worldwide suffer from diseases that lead to paralysis through disruption of signal pathways between the brain and the muscles. Neuroprosthetic devices are designed to restore lost function and could be used to form an electronic ‘neural bypass’ to circumvent disconnected pathways in the nervous system. It has previously been shown that intracortically recorded signals can be decoded to extract information related to motion, allowing non-human primates and paralysed humans to control computers and robotic arms through imagined movements1,2,3,4,5,6,7,8,9,10,11. In non-human primates, these types of signal have also been used to drive activation of chemically paralysed arm muscles12,13. Here we show that intracortically recorded signals can be linked in real-time to muscle activation to restore movement in a paralysed human. We used a chronically implanted intracortical microelectrode array to record multiunit activity from the motor cortex in a study participant with quadriplegia from cervical spinal cord injury. We applied machine-learning algorithms to decode the neuronal activity and control activation of the participant’s forearm muscles through a custom-built high-resolution neuromuscular electrical stimulation system. The system provided isolated finger movements and the participant achieved continuous cortical control of six different wrist and hand motions. Furthermore, he was able to use the system to complete functional tasks relevant to daily living. Clinical assessment showed that, when using the system, his motor impairment improved from the fifth to the sixth cervical (C5–C6) to the seventh cervical to first thoracic (C7–T1) level unilaterally, conferring on him the critical abilities to grasp, manipulate, and release objects. This is the first demonstration to our knowledge of successful control of muscle activation using intracortically recorded signals in a paralysed human. These results have significant implications in advancing neuroprosthetic technology for people worldwide living with the effects of paralysis.
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We thank the study participant for his dedication and his family for their support. We also thank the development team and management at Battelle Memorial Institute for their support, the surgical support team, C. Majstorovic for assistance with data analysis and equipment during sessions, S. Preston for stereo camera coding and troubleshooting, the clinical study support staff, W. Pease for performing the electromyogram and nerve conduction studies, and M. Zhang for assistance with figure preparation. Financial support for this study came from Battelle Memorial Institute and The Ohio State University Center for Neuromodulation.
Extended data figures
Participant Attempting the Individual Hand Movement Task without the Use of the Neural Bypass System
This video shows the participant attempting the individual hand movement task without the use of the NBS. The participant was unable to successfully perform any of the movements. The small graphical hand shown on the monitor in the video, along with captions in the video, indicates which movement the participant was being cued to perform at the time. The entire test block is shown in the movie. [Video taken by Nicholas Annetta]
This video shows the participant performing the individual hand movement task with the use of the NBS. The small graphical hand shown on the monitor in the video, along with captions in the video, indicates which movement the participant was being cued to perform at the time. The entire test block is shown in the movie. [Video taken by Nicholas Annetta]
This video shows two representative trials where the participant was successful in performing the functional movement task with the use of the NBS. Captions in the video indicate the movement that was being performed at the time. [Video taken by Nicholas Annetta]
This video shows two representative trials where the participant was not successful in performing the functional movement task without the use of the NBS. He was able to force his hand around the bottle, but without any grip strength, and therefore was unable to lift the bottle and pour the contents. The participant was then asked to attempt the stir stick grasp and stirring portion of the task separately. He was able to wedge the stir stick between his fingers and use friction to lift it out of the jar, but without any grip strength, he was unable to complete the stirring motion without the stir stick falling out of his hand. Captions in the video indicate the movement he was attempting at the time. [Video taken by Nicholas Annetta]