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Electric field measurement of two commercial active/sham coils for transcranial magnetic stimulation.

Publication ,  Journal Article
Smith, JE; Peterchev, AV
Published in: J Neural Eng
October 2018

OBJECTIVE: Sham TMS coils isolate the ancillary effects of their active counterparts but typically induce low-strength electric fields (E-fields) in the brain, which could be biologically active. We measured the E-fields induced by two pairs of commonly-used commercial active/sham coils. APPROACH: E-field distributions of the active and sham configurations of the Magstim 70 mm AFC and MagVenture Cool-B65 A/P coils were measured over a 7 cm-radius, hemispherical grid approximating the cortical surface. Peak E-field strength was recorded over a range of pulse amplitudes. MAIN RESULTS: The Magstim and MagVenture shams induce peak E-fields corresponding to 25.3% and 7.72% of their respective active values. The MagVenture sham has an E-field distribution shaped like its active counterpart. The Magstim sham induces nearly zero E-field under the coil's center, and its peak E-field forms a diffuse oval 3-7 cm from the center. Electrical scalp stimulation paired with the MagVenture sham is estimated to increase the sham E-field in the brain up to 10%. SIGNIFICANCE: Different commercial shams induce different E-field strengths and distributions in the brain, which should be considered in interpreting outcomes of sham stimulation.

Duke Scholars

Published In

J Neural Eng

DOI

EISSN

1741-2552

Publication Date

October 2018

Volume

15

Issue

5

Start / End Page

054001

Location

England

Related Subject Headings

  • Transcranial Magnetic Stimulation
  • Humans
  • Equipment Design
  • Electromagnetic Fields
  • Electric Stimulation
  • Brain
  • Biomedical Engineering
  • 4003 Biomedical engineering
  • 3209 Neurosciences
  • 1109 Neurosciences
 

Citation

APA
Chicago
ICMJE
MLA
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Smith, J. E., & Peterchev, A. V. (2018). Electric field measurement of two commercial active/sham coils for transcranial magnetic stimulation. J Neural Eng, 15(5), 054001. https://doi.org/10.1088/1741-2552/aace89
Smith, J Evan, and Angel V. Peterchev. “Electric field measurement of two commercial active/sham coils for transcranial magnetic stimulation.J Neural Eng 15, no. 5 (October 2018): 054001. https://doi.org/10.1088/1741-2552/aace89.
Smith, J. Evan, and Angel V. Peterchev. “Electric field measurement of two commercial active/sham coils for transcranial magnetic stimulation.J Neural Eng, vol. 15, no. 5, Oct. 2018, p. 054001. Pubmed, doi:10.1088/1741-2552/aace89.
Journal cover image

Published In

J Neural Eng

DOI

EISSN

1741-2552

Publication Date

October 2018

Volume

15

Issue

5

Start / End Page

054001

Location

England

Related Subject Headings

  • Transcranial Magnetic Stimulation
  • Humans
  • Equipment Design
  • Electromagnetic Fields
  • Electric Stimulation
  • Brain
  • Biomedical Engineering
  • 4003 Biomedical engineering
  • 3209 Neurosciences
  • 1109 Neurosciences