Dual Transcranial Direct Current Stimulation (dTDCS)-Enhanced Therapy After Hemorrhagic Strokes and VEGF

This study will evaluate the feasibility of dual tDCS to improve arm motor function in chronic stroke patients. In addition it will collect pilot data on the blood biomarkers associated with treatment effect.

The proposed, increased intensity dtDCS is a new, economical, noninvasive stimulation approach that has the potential for large-scale clinical application. Dual tDCS, in conjunction with physical and occupational therapy, is not only more effective in enhancing motor performance and cortical plasticity compared to sham, but approximately 50% more effective than cathodal or anodal stimulation in healthy subjects and after stroke. However, it will only be clinically useful and important if the beneficial effects persist over time in a wider stroke patient population. Improvement in inter-hemispheric balance, through an activation shift toward the affected hemisphere and clinical improvement in response to tDCS has been reported previously in small studies. Hemorrhagic stroke patients have not been evaluated. The investigators will study rehabilitation associated cortical plasticity at a cellular level to gain insight into the neural substrates underlying the clinical improvement. There are no prior studies investigating the potential of VEGF polymorphisms to contribute to rehabilitative treatment-induced functional recovery in humans. The investigators expect that patients with VEGF genotype 2578A/A will recover less then subjects without this polymorphism. Since in animal models VEGF and BDNF have a complimentary role, VEGF polymorphism may explain some of the variability in strength of association between BDNF polymorphism Val66Met and recovery. This novel pilot study measures both the genetic and physiologic expression of multiple growth factors - before and after a promising new therapy regimen - to better understand the contribution of growth factors to long-term plasticity and functional recovery. If VEGF serum levels elevate with clinical improvement, then this may identify a new indicator of treatment efficacy that can be collected noninvasively and with little cost. The results will provide guidance for new inclusion/exclusion criteria for clinical studies based on genetic markers, as well as uncover the potential for new therapeutic strategies to enhance treatment efficacy by augmenting VEGF during rehabilitation with FDA-approved strategies currently in clinical trials for other conditions (NIH Clinical Trials Registry: NCT01384162, NCT00620217, and NCT00744315).