A soft robotic extra-finger and arm support to recover grasp capabilities in chronic stroke patients

In this paper, we present the combination of the Soft-SixthFinger, a wearable robotic extra-finger designed to be used by chronic stroke patients to compensate for the missing hand function, with a robotic arm that is used as an assistive device to support the patient arm. The extra-finger is a tendon-driven modular structure worn at the paretic forearm. The robotic extra-finger is used jointly with the paretic hand/arm to grasp an object similarly to the two parts of a robotic gripper. The flexion/extension of the robotic finger is controlled by the patient using an Electromyography (EMG) interface embedded in a cap. The robotic arm is controlled to partially compensate for the weight of the paretic arm, while not interfering with the user arm motion. The system has been designed as a tool that can be used by chronic stroke patients to compensate for grasping in many Activities of Daily Living (ADL). We performed a pilot test to demonstrate that the proposed system can significantly improve the performance and the autonomy in ADL.