The numeric calculation of eddy current distributions in transcranial magnetic stimulation

Annu Int Conf IEEE Eng Med Biol Soc. 2008:2008:4286-9. doi: 10.1109/IEMBS.2008.4650157.

Abstract

Transcranial magnetic stimulation (TMS) is a method to stimulate neurons in the brain. It is necessary to obtain eddy current distributions and determine parameters such as position, radius and bend-angle of the coil to stimulate target area exactly. In this study, we performed FEM-based numerical simulations of eddy current induced by TMS using three-dimentional human head model with inhomogeneous conductivity. We used double-cone coil and changed the coil radius and bend-angle of coil. The result of computer simulation showed that as coil radius increases, the eddy current became stronger everywhere. And coil with bend-angle of 22.5 degrees induced stronger eddy current than the coil with bendangle of 0 degrees. Meanwhile, when the bend-angle was 45 degrees, eddy current became weaker than these two cases. This simulation allowed us to determine appropriate parameter easier.

MeSH terms

  • Algorithms
  • Brain / anatomy & histology
  • Brain / physiology*
  • Electric Conductivity
  • Electric Stimulation / instrumentation*
  • Electric Stimulation / methods
  • Electromagnetic Fields
  • Equipment Design
  • Humans
  • Magnetics
  • Mental Disorders / physiopathology
  • Mental Disorders / therapy*
  • Models, Neurological
  • Numerical Analysis, Computer-Assisted
  • Transcranial Magnetic Stimulation / methods*