Current research suggests there may be potential benefit using high definition transcranial direct current stimulation in patients with upper extremity hemiparesis secondary to an ischemic stroke. The intervention has effects on the damaged neurons within the person's brain after stroke possibly amplifying the body's own healing process. These data are compelling but not always statistically significant, which could be due to several reasons. One is the lack of a definitive protocol involving timing of the intervention relative to therapy, lead placement, an unclear dose-response relationship, and variable conductance of tissue and skull thickness. Hummel et al (2008) suggested that stimulation during or before intensive therapy yielded improved motor function or reaction time than when no therapy was given around the stimulation. Several other review articles and studies suggest using both high definition tDCS, which increases the focality of the current, and/or using neurotargeting software that uses the patient's own CT/MRI in the computation of the electrical montage can create a more personalized tDCS regimen.7,11,12 This study plans to do both. The Soterix MxN neuromodulation system has been used in multiple studies and has a targeting system that would help ensure both ideal current, more focal stimulation and optimal lead placements is essential as according to Datta et al (2011). Lesions within the brain may alter the flow of current through that area. The software system, HD-Targets, will be used that takes the patient's own MRI to account for variabilities in skull thickness, lesion size/location/composition, fluid density, and cerebrospinal fluid presence. These variabilities are used in the computer algorithm that simulates current flow through that specific participant's brain to get to the desired target area with the least amount of current and decreased stimulation of undesired areas. The investigators will examine these patients before and after treatment and compare the two groups, treatment group and sham group, after they receive 10 sessions of 20minutes along with their regular course of physical, occupational, or speech therapy over the course of their inpatient rehab stay.

Subjects will be given high definition transcranial direct current stimulation (tDCS) via a Soterix MxN HD-tDCS stimulator. This device is for investigational use only at this time and is not FDA approved. However, it has been used in several multicenter and randomized control trials that are detailed below in Appendix 1. The patient's MRi will be sent out to Soterix where they will manually input the variations in skull thickness, fluid density, lesion size, cerebrospinal fluid, and gray/white matter variabilities. They will then run the algorithm with HD-Targets, sophisticated current simulating software, to obtain optimal electrode placement to target the primary motor cortex (M1 area), the region of the brain that is responsible for movement, of each individual patient. Another issue with tDCs is maintaining optimal connections between the patient's scalp and the electrodes. Sotetrix HD-tDCs uses SmartScan™ to assure proper lead contact with initial set-up to adjust electrodes and head-gear for optimal fit. During stimulation, SmartScan™ provides a constant indication of electrode quality and can be monitored during adjustments to assure continuous lead contact.