Spinal cord injury (SCI) affects millions worldwide, with over half of all cases resulting in tetraplegia, where a complete injury can cause profound motor and sensory loss in all four limbs1. Here, we demonstrate an artificial "double neural bypass" (DNB) that integrates a bidirectional intracortical brain-computer interface with targeted spinal and brain stimulation to promote restoration of upper limb function in severe, complete paralysis. This hybrid assistive-therapeutic approach restores both hand movement and tactile sensation simultaneously via cortical mediation while promoting significant persistent sensorimotor improvements. The DNB uses a stable nested neural decoding architecture with deep reinforcement learning for fine grasping, along with patterned brain microstimulation ("cortical mirroring") and spinal cord stimulation to promote real-time and long-term functional recovery. Using the DNB, our participant with chronic C4 sensory/C5 motor complete tetraplegia regained the ability to self-feed, grasp delicate objects, and experienced persistent recovery of arm flexion and wrist tactile sensation. These findings represent a major advance in restoring meaningful function after severe, complete SCI, demonstrating that bidirectional neuroprostheses combined with targeted brain and spinal neuromodulation can drive durable sensorimotor recovery and improve independence and quality of life.
Chandrasekaran et al. (Thu,) studied this question.