65. Intracortical and interhemispheric changes induced by Transcutaneous spinal Direct Current Stimulation (tsDCS)

Abstract

Transcutaneous spinal Direct Current Stimulation (tsDCS) is a new and safe technique for modulating spinal cord excitability. We evaluated the effects of supraspinal and cortical stimulation in healthy subjects before (T0) and at different intervals (T1, T2) after anodal, cathodal and sham tsDCS (20′, 2.0 mA) applied over the thoracic spinal cord (T10–T12). We studied the effects of tsDCS on cortical Silent Period (cSP), paired-pulse short intracortical inhibition (SICI, interstimulus interval = 3 ms), intracortical facilitation (ICF, ISI = 10 ms), interhemispheric motor connectivity and visual processing (ipsilateral Silent Period, iSP; Transcallosal Conduction Time, TCT; hemifield Visual Evoked Potentials, hVEPs). Cathodal tsDCS (c-tsDCS) decreased SICI, while anodal one elicited opposite effects (FDI: p = 0.0023; TA: p = 0.0004); conversely, tsDCS left ICF and cSP duration unchanged. Moreover, anodal tsDCS increased TCT (p < 0.001) and the interhemispheric delay for both the main VEP components (N1: p = 0.0003; P1: p < 0.0001), dampening at the same time iSP duration (APB: p < 0.0001; AH: p = 0.0005; deltoid: p < 0.0001), while cathodal stimulation had opposite effects (p < 0.0001). tsDCS a useful approach, complementary to either SCS or non-invasive brain stimulation techniques, to restore spinal drive through supra-spinal modulating mechanisms; tsDCS could also represent an early rehabilitation strategy in patients with sub-acute brain lesions, when transcranial stimulation is avoided due to safety concerns.