COMPARISON OF BEM AND FEM METHODS FOR THE E/MEG PROBLEM

The direct E/MEG problem consists of simulating the electromagnetic field produced by neuronal electric sources on the cortex. We compare two different methods for the resolution of this problem, mainly from the point of view of computational complexity and accuracy. First, the finite element method (FEM), based on the discretization of the PDE in the entire head volume. Second, the boundary element method (BEM), discretizing the equivalent integral equations on the surfaces separating volumes with different electrical parameters. We also study the behaviour of the BEM and FEM methods for the sources approaching the discontinuity in conductivity, as it makes the accuracy of the solution decrease. We conclude that at the current state of investigation, for equivalent triangulation/tetraheaderisation, the FEM is significantly faster than BEM and provides similar or better accuracy. It should therefore be used whenever the volumic tetraheadric mesh is available.