Reclaiming Motor Functions after Complete Spinal Cord Injury using Epidural Minimally Invasive Brain-Computer Interface

Background: Spinal cord injuries significantly impair patients' ability to perform daily activities independently. While invasive brain-computer interfaces (BCIs) offer high communication bandwidth to assist and rehabilitate these patients, their invasiveness limits broader adoption. Methods: We developed a minimally invasive BCI system that balances safety and communication bandwidth to restore hand functions of tetraplegia patients. This system enables real-time, precise control of hand movements and hand function rehabilitation. A complete spinal cord injury (SCI) patient with deficit hand functions was recruited in this study. Results: The system required less than 10 minutes of calibration time and maintained an average grasping detection F1-score of 0.91 over a 9-month period of home use. With the assistance of the brain-computer interface, the patient can achieve a 100% success rate in object transfer tests, and successfully perform daily tasks involving hand functions. Additionally, the patient showed substantial neurological recovery through consecutive BCI training, regaining the ability to hold objects without BCI assistance. The patient exhibited a 5-point improvement in upper limb motor scores and a 27-point increase in the Action Research Arm Test (ARAT). Improvements in electrophysiological assessments point to a considerable recovery in impaired neural circuits. Conclusions: In a tetraplegia patient with complete spinal cord injury, an epidural minimally invasive BCI assisted the patient's hand grasping to perform daily tasks, and 9-month consecutive BCI use significantly improved the hand functions.