Symmetric motions for bimanual rehabilitation

Many daily tasks require that a person use both hands simultaneously, such as moving a large book or opening the lid on a jar. Such bimanual tasks are difficult for people who have a stroke, but the tight neural coupling across the body has been hypothesized to allow individuals to self-rehabilitate by physically coupling their hands. To examine potential methods for robot-assisted bimanual rehabilitation, we performed a haptic tracking task where individuals experience a one degree of freedom trajectory on one hand and attempt to recreate it with their other hand. Despite the biomechanical and neurological symmetries present across the human body, subjects performed this task worse when working in the joint space (i.e., mirrored motion) than they did in the visually centered space. We also examined multiple input paths and show alternative rhythmic motions that may aid in rehabilitation.