Quantitative modeling of electric field in deep brain stimulation: Study of medium brain tissue and stimulation pulse parameters

This paper introduces a finite difference time domain (FDTD) model for the electromagnetic simulation and analysis of a 4-channel deep brain stimulation (DBS) electrode. The analysis uses non-homogenous tissue models representing the gray and white tissue matter. The model includes the encapsulation layer of unexcitable tissues. Several low frequency signal models for brain tissue and the DBS electrode are developed to investigate the effect of the dielectric properties, stimulation pulse parameters and firing pattern (current steering) on controlling the field intensity distribution. These models are used to provide a quantitative formulation of the tissue-field interaction and the parameters influencing the electric field distribution within the brain tissue. The simulation results provide reference and benchmarking data for DBS electrode development.