FINGER Robot Therapy Study

Inclusion Criteria: * Age 18 to 80 years of age * Have history of stroke affecting the arm, at least 6 months prior to enrollment * have arm and/or hand weakness as measured on a standard clinical scale * do not have active major psychological problems, or problems affecting the stroke-affected arm or hand besides the stroke * do not have active major brain disease other than the stroke * have absence of pain in the stroke-affected arm and hand Exclusion Criteria: * severe stiffness of the arm or hand as measured on a standard clinical scale * severe problems speaking or understanding speech as measured on a standard clinical scale * severe reduced level of consciousness * severe loss ability to sense movement of your limbs as measured on a standard clinical scale * currently pregnant * difficulty in understanding or complying with the instructions given by the researcher * inability to perform the experimental task that will be studied * increased pain with movement of the stroke-affected arm or hand Exclusion criteria that will prevent subjects from participating in the MRI: * Subjects having any implanted metal such as metallic splinters, metallic surgical clips, prosthetic heart valves, pacemakers, neuro-stimulation devices, orthodontic work that contains ferromagnetic materials, * Subjects whose occupation or activities may cause accidental lodging of ferromagnetic materials, or that may have imbedded metal fragments from military activities, unless cleared by a screening head CT scan * Subjects with tattoo(s) presenting metallic or ferromagnetic color ingredients or with facial make-up * Subjects who have claustrophobia * Subjects who are currently pregnant or breastfeeding.