title: Comparing cutaneous perception induced by electrical stimulation using rectangular and round shaped electrodes.
abstract: 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 μA 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.
  
  
  CONCLUSIONS
  We conclude that there is no difference between the round and the rectangular electrode configurations regarding their blinding potentials.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Clinical Neurophysiology, Georg-August University of Göttingen, 37075 Göttingen, Germany. g.ambrus@gmail.com
authors.forename: Géza Gergely
authors.initials: GG
authors.lastname: Ambrus
authors.forename: Andrea
authors.initials: A
authors.lastname: Antal
authors.forename: Walter
authors.initials: W
authors.lastname: Paulus
mesh_terms: D000328:Adult; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004867:Equipment Design; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D010465:Perception / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D012867:Skin / Q000294:innervation*; D012879:Skin Physiological Phenomena; D055815:Young Adult