Transcranial direct current stimulation effects on hand sensibility as measured by an objective quantitative analysis...

Studies show that transcranial direct current stimulation (tDCS) can modulate somatosensory processing, but optimum parameters for tDCS effects on hand sensibility remain in question. We aimed to test the effects of anodal tDCS (atDCS) and cathodal tDCS (ctDCS) compared with sham tDCS (stDCS) of primary motor (M1) and sensory (S1) cortices on healthy subjects' hand sensibility. In this single-blind clinical trial, 30 randomized healthy volunteers received six tDCS sessions over 6 weeks: one session each of atDCS, ctDCS and stDCS over M1, and one session each of atDCS, ctDCS and stDCS over S1. Current perception threshold (CPT) was assessed using an objective quantitative analysis device (PainVision) at baseline, immediately (T0) and 30 min (T30) after each intervention. Our results showed that both atDCS and ctDCS of S1 and M1 significantly increased CPT. M1 ctDCS at T30 had the greatest effect of all M1 and S1 stimulation conditions (mean difference: 32.94%, Z: 3.12, effect size: 1.82, P < 0.001 The largest effect at S1 was for atDCS at T30 (mean difference: 29.87%, Z: 2.53, effect size: 1.72, P < 0.001. Our results are consistent with tDCS' modulatory effects on hand sensation, especially M1 ctDCS and S1 atDCS.