Brain Stimulation and Robotics in Chronic Stroke Motor Recovery

Motor skill training and transcranial direct current stimulation (tDCS) have separately been shown to alter cortical excitability and enhance motor function in humans. Their combination is appealing for augmenting motor recovery in stroke patients, and this is an area presently under heavy investigation globally. The investigators have previously shown that the timing of tDCS application has functional significance, that tDCS applied prior to training can be beneficial for voluntary behavior, and that tDCS effects may not simply be additive to training effects, but may change the nature of the training effect. The investigators have separately reported in a randomized-controlled clinical trial, that upper limb robotic training alone over 12 weeks can improve clinical function of chronic stroke patients. Based on our results with tDCS and robotic training, the investigators hypothesize that the same repeated sessions of robotic training, but preceded by tDCS, would lead to a sustained and functional change greater than robotic training alone. The investigators will determine if clinical function can be improved and sustained with tDCS-robotic training and cortical physiology changes that underlie functional improvements.