Validation of finite element model of transcranial electrical stimulation using scalp potentials: implications for clinical dose

J Neural Eng. 2013 Jun;10(3):036018. doi: 10.1088/1741-2560/10/3/036018. Epub 2013 May 7.

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.

Approach: 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.

Main 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.

Significance: 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.

Publication types

  • Evaluation Study
  • Validation Study

MeSH terms

  • Action Potentials / physiology*
  • Adult
  • Brain / physiology*
  • Brain / radiation effects
  • Brain Mapping / methods*
  • Computer Simulation
  • Finite Element Analysis
  • Humans
  • Male
  • Models, Neurological*
  • Scalp / physiology*
  • Scalp / radiation effects
  • Transcranial Magnetic Stimulation / methods*