Cortical Enhancement of Posture, Movement Planning, and Execution of Upright Reaching Following Stroke

Stroke is the leading cause of disability and diminished quality of living that frequently includes impairments of postural control and upper extremity (UE) function. The interaction of posture and UE coupling in terms of movement planning, initiation, and execution is not well understood. StartReact responses triggered by a loud acoustic stimulus (LAS) during the planning and preparation of goal intended actions has been used to probe the state of brainstem neuronal excitability related to posture and movement sequencing. The purpose of this study is to examine posture and goal-directed movement planning and execution using startReact responses and to evaluate posture and UE movement sequence during reaching while standing in individuals with chronic hemiparesis and healthy controls. Secondly, the investigators will determine the modulatory role of the cortical premotor areas (PMAs) in startReact responses in healthy controls and in persons with stroke by using transcranial direct current stimulation (tDCS) to up- or down-regulate PMAs excitability.