Kinematic Benefits of a Cable-Driven Exosuit for Head-Neck Mobility

This letter presents a novel cable-driven exosuit intended for head-neck support and movement assistance. Mobility limitations in the head-neck, such as dropped head syndrome, can result from various neurological disorders. Current solutions, ranging from static neck collars to rigid-link robotic neck exoskeletons, are unsatisfactory. Neck collars are the most used clinically but fail to restore head-neck motion. Rigid-link neck exoskeletons can enable head movement but are bulky and restrictive. In this letter, we present the design of this exosuit, an analysis of its ability to balance the gravitational moment of the head in simulation, and the results of a user study comparing its kinematic performance to a state-of-the-art rigid-link neck exoskeleton. The exosuit is able to support the head across its full range of motion according to simulation results. It fits users of different sizes and participants exhibited more natural head-neck movement wearing the exosuit as compared to wearing the rigid-link exoskeleton. The exosuit allowed more head rotations than the rigid-link neck exoskeleton and required less compensatory torso movement for three daily tasks (looking for traffic, drinking from a bottle, and picking up an object from the floor). Its absolute range of motion was also much larger than the one allowed by the rigid-link neck exoskeleton. These results demonstrate the kinematic benefits of a cable-driven neck exosuit and provide justification for studying the use of such an exosuit for head-neck movement assistance in patient groups.