Current efforts related to post-stroke arm rehabilitation focus primarily on motor retraining, with limited focus on mitigating the impact of somatosensory deficits on motor function. Somatosensory deficits are common in the contralesional arm, and contribute importantly to deficits in the control of functional movement. This project seeks to promote functional motor recovery after stroke by using technologies that re-establish kinesthetic feedback control of the contralesional arm. These technologies will deliver supplemental feedback ("sensory augmentation") about contralesional arm movement to a body part that retains somatosensation. The focused objective of this application is to engage undergraduate students in a mechanistic clinical trial. Two hypotheses will be used to guide this project. The first posits that stroke survivors can improve contralesional arm control through extended training on a planar reaching task guided by supplemental feedback. The second posits that extended training on that 2D (2 degree-of-freedom) task facilitates subsequent performance of more challenging 3D reach-to-grasp actions guided by 3D supplemental feedback. This study has two Aims. The first will characterize learning due to extended training with supplemental kinesthetic feedback during planar reaching with the contralesional arm after stroke. Over a period of 4 to 6 weeks, two groups of stroke survivors will receive ten hours of training with supplemental feedback as they perform goal-directed reaching with their more involved arm in the horizontal plane. One group will train using a 2D vibrotactile display that encodes the instantaneous position and velocity of the moving hand (state feedback). The other group will train using feedback that encodes the instantaneous Euclidean error between the hand and the desired spatial target (error feedback). We will compare changes in movement accuracy and efficiency within and across groups to test our first hypothesis and to determine which form of feedback proves easier to learn. The second Aim will quantify the ability of extended reach training to enhance unconstrained 3D reach-to-grasp actions performed with the contralesional arm. We will test subjects before and after 2D reach training on their ability to use supplemental kinesthetic feedback to guide unconstrained 3D reach-to-grasp actions that contribute to the success of many behaviors of daily living. We will compare movement accuracy and efficiency across the groups to test our second hypothesis and to determine whether state or error feedback training better supports reach-to-grasp behaviors. On completion, this project will identify whether state or error encoding best promotes accuracy and efficiency of movements performed with the contralesional arm. This project will provide a critical test of a progressive 2D-to-3D training strategy intended to promote actions that enhance quality of life. The results will guide future clinical efforts to maxi...