Comparing cutaneous perception induced by electrical stimulation using rectangular and round shaped electrodes

Objective: We have investigated the cutaneous perception differences for anodal and cathodal transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS) between two electrode configurations: a standard, rectangle-shaped, and a circle-shaped, round geometry with the same surface area, and thus, same nominal current distribution. We have aimed to find whether a smaller perimeter length and the absence of corners in the case of the round configuration would lead to altered skin perception characteristics when compared to the rectangular geometry. Methods: Twelve subjects were tested for tDCS and tRNS skin perception characteristics in the intensity range of 200-2000 mu A using round and rectangular electrode configurations. Results: We have not found any substantial differences between detection thresholds, detection rates, false positive rates or consistent alterations in the sites of perceived stimulation. Conclusion: We conclude that there is no difference between the round and the rectangular electrode configurations regarding their blinding potentials. Significance: The results of this investigation indicate that the altering of the electrode geometry to a round configuration is unwarranted for better blinding purposes in future studies using tDCS and tRNS. (C) 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.