Maintaining Seated Posture With Feedback Control of Trunk Musculature Via the Networked Neuroprosthesis After Paralysis

Trunk control has consistently been rated as a priority for recovery by individuals with spinal cord injury due to its role in facilitating interactions with the environment from a seated position. Feedback control of functional neuromuscular stimulation with the networked neuroprosthesis is a promising solution for automatically stabilizing seated posture after spinal cord injury by controlling the activation of paralyzed trunk muscles via accelerometers embedded in implanted modules. This study examined the design of a control system for implanted stimulation in an individual with cervical spinal cord injury who received an Networked Neuroprosthesis. A tilt-based threshold feedback controller modulated the stimulation that activated the paralyzed hip and trunk muscles such that the controller prevented the individual's trunk from moving beyond arbitrarily defined limits of seated leaning in the sagittal and coronal planes. Findings suggest that such a controller for the networked neuroprosthesis can enable individuals with spinal cord injury to complete returns to erect sitting from approximately 30° of forward or lateral flexion without external sensors and confirms the feasibility of deploying feedback-controlled functional neuromuscular stimulation to restore motor function using the fully implanted networked neuroprosthesis system.