ReGrasp, a Robotic Tool to Investigate Fine Motor Control and Track Therapy-Induced Neuroplasticity

The neural mechanisms of fine motor control and recovery, e. g. after a stroke, are not fully understood, nor how these are influenced by different types of motor therapies, leaving potential for optimization of current rehabilitation strategies. This paper presents the development and evaluation of a novel robotic tool for fMRI-based neuroscience studies allowing to investigate the neural mechanisms of dynamic precision grip and track therapy-induced neuroplasticity. In this proof of principle study we investigate the feasibility of high-fidelity haptic interaction with human motion using remote sensing and actuation. A cable-spring mechanism transmits force to the thumb and index finger in an unconstrained manner, actuated over a stiff cable transmission. Characterization of the prototype with a transmission length of two meters revealed good dynamic performance including a 16 Hz open loop force bandwidth and a maximal output force of 28 N. Combined with a remote and shielded conventional electromagnetic actuator, this device could be used to investigate the neural correlates of precision grasping as well as the effect of different hand function therapies on the neural correlates of motor recovery after stroke.