Determining Electrode Placement for Transcranial Direct Current Stimulation: A Comparison of EEG- Versus TMS-Guided Methods

Tonya L. Rich, Jeremiah S. Menk, Kyle D. Rudser, Mo Chen, Gregg D. Meekins, Edgar Peña, Timothy Feyma, Kay Bawroski, Christina Bush, Bernadette T. Gillick

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24 Scopus citations


Transcranial direct current stimulation (tDCS) is increasingly researched as an adjuvant to motor rehabilitation for children with hemiparesis. The optimal method for the primary motor cortex (M1) somatotopic localization for tDCS electrode placement has not been established. The objective, therefore, was to determine the location of the M1 derived using the 10/20 electroencephalography (EEG) system and transcranial magnetic stimulation (TMS) in children with hemiparesis (CWH) and a comparison group of typically developing children (TDC). We hypothesized a difference in location for CWH but not for TDC. The 2 locations were evaluated in 47 children (21 CWH, 26 TDC). Distances between the locations were measured pending presence of a motor evoked potential. Distances between the EEG and TMS locations that exceeded the 2.5 cm × 2.5 cm rubber electrode area are reported in percentages [95% confidence interval] in CWH - nonlesioned hemisphere was 68.8% [41.3-89.0], lesioned: 85.7% [57.2-98.2]; TDC - dominant hemisphere 73.9% [51.6-89.8], nondominant: 82.6% [61.2-95.0]. Distances that exceeded the 3 × 5 cm electrode sponge area in CWH - nonlesioned was 25.0% [7.3-52.4], lesioned was 28.6% [8.4-58.1]; TDC - dominant was 52.2% [30.6-73.2], nondominant was 43.5 [23.2-65.5]). Distances that exceeded the 5 × 7 cm electrode sponge area in CWH - nonlesioned was 18.8% [4.0-45.6] and lesioned was 21.4% [4.7-50.8]; TDC - dominant was 21.7% [7.5-43.7] and nondominant was 26.1% [10.2-48.4]. Individual variability in brain somatotopic organization may influence surface scalp localization of underlying M1 in children regardless of neurologic impairment. Findings suggest further investigation of optimal tDCS electrode placement. EEG and TMS methods reveal variability in localizing M1 in children regardless of stroke diagnosis. This study was registered on NCT02015338.

Original languageEnglish (US)
Pages (from-to)367-375
Number of pages9
JournalClinical EEG and Neuroscience
Issue number6
StatePublished - Nov 1 2017

Bibliographical note

Funding Information:
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Institutes of Health (K01– 1K01HD078484-01A1); KL2 (UL1 RR033184 and 1KL2RR033182); the National Center for Advancing Translational Science (NCATS) Award (UL1TR000114); the Center for Magnetic Resonance Research (University of Minnesota) Grant (P41 EB015894); Minnesota’s Discovery, Research, and Innovation Economy (MnDRIVE) Fellowship; and the Center for Neurobehavioral Development (University of Minnesota).

Publisher Copyright:
© EEG and Clinical Neuroscience Society (ECNS) 2017.


  • neuroplasticity
  • noninvasive brain stimulation
  • pediatrics
  • stroke
  • transcranial direct current stimulation
  • transcranial magnetic stimulation


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