Comparison of the Effectiveness of Different transcranial direct current stimulation Protocols (tDCS) with Cognitive Exercises in Improving Response Inhibition in Normal Individuals

Introduction: Studies have shown that the anodal tDCS is able to increase the effectiveness of cognitive rehabilitation. On the other hand, results of recent studies have shown that unihemispheric concurrent dual-site a-tDCS could increase the corticospinal excitability. Aim: The present study compares the effectiveness of unihemispheric concurrent dual-site atDCS and conventional tDCS, during cognitive exercises in improving the response inhibition of normal individuals. Method: 21 subjects were randomly assigned into two experimental groups as well as a control group. First group received Anodal tDCS over the left DLPFC and M1, the second group received Anodal tDCS over the left DLPFC and Control group received sham a-tDCS. Transcranial direct current stimulation (tDCS) at 0.3 mAh was applied directly for 30 minutes in 4 sessions. All subjects, after interventions in each session, performed the stop signal task. In Fifth session, In order to follow up the effectiveness of interventions, 24 hours after the interventions, subjects were re-evaluated. Results: The results of repeated measurements analysis revealed that compared with conventional tDCS and control group, unihemispheric concurrent dual-site a-tDCS group had larger improvement in improving the response inhibition of normal individuals (P.05). Conclusion: The results show that unihemispheric concurrent dual-site a-tDCS could enhance the effectiveness of cognitive exercises by increasing cortical excitability.