An Implantable Digital Bridge Enables Arm And Hand Movements After Tetraplegia

A cervical spinal cord injury disrupts the signals between the brain and the region of the spinal cord that coordinates arm and hand movements, causing paralysis. Here, we engineered a chronically implanted and durable Digital Bridge that reestablishes communication between the brain and cervical spinal cord. This technology consists of a brain implant to record electrocorticography from the sensorimotor cortex, and a neurostimulation platform to deliver epidural electrical stimulation over the entire cervical spinal cord unilaterally. We implanted this Digital Bridge in three individuals with chronic incomplete tetraplegia. We configured a library of stimulation patterns that supported gradual control over various elementary movements of the arm and hand. A decoding pipeline incorporating a foundation model of human brain activity predicted up to 8 motor states with high accuracy. In turn, linking decoding predictions to the modulation of stimulation patterns targeting the preprogrammed elementary movements enabled the three participants to perform functional tasks with their otherwise paralyzed arm and hand. The Digital Bridge has remained stable for more than one year, and has been compatible with long-term stability and safety. While additional technological developments and clinical validations in a diverse patient population are required, these results establish essential concepts to enable arm and hand movements in humans living with chronic tetraplegia.