title: Validation of finite element model of transcranial electrical stimulation using scalp potentials: implications for clinical dose.
abstract: OBJECTIVE
  During transcranial electrical stimulation, current passage across the scalp generates voltage across the scalp surface. The goal was to characterize these scalp voltages for the purpose of validating subject-specific finite element method (FEM) models of current flow.
  
  
  METHODS
  Using a recording electrode array, we mapped skin voltages resulting from low-intensity transcranial electrical stimulation. These voltage recordings were used to compare the predictions obtained from the high-resolution model based on the subject undergoing transcranial stimulation.
  
  
  RESULTS
  Each of the four stimulation electrode configurations tested resulted in a distinct distribution of scalp voltages; these spatial maps were linear with applied current amplitude (0.1 to 1 mA) over low frequencies (1 to 10 Hz). The FEM model accurately predicted the distinct voltage distributions and correlated the induced scalp voltages with current flow through cortex.
  
  
  CONCLUSIONS
  Our results provide the first direct model validation for these subject-specific modeling approaches. In addition, the monitoring of scalp voltages may be used to verify electrode placement to increase transcranial electrical stimulation safety and reproducibility.
authors: Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of City University of New York, NY 10031, USA.
authors: Abhishek
authors: A
authors: Datta
authors: Xiang
authors: X
authors: Zhou
authors: Yuzhou
authors: Y
authors: Su
authors: Lucas C
authors: LC
authors: Parra
authors: Marom
authors: M
authors: Bikson
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D001921:Brain / Q000502:physiology* / Q000528:radiation effects; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008959:Models, Neurological; D012535:Scalp / Q000502:physiology* / Q000528:radiation effects; D050781:Transcranial Magnetic Stimulation / Q000379:methods*