Surface charge method for the forward EEG problem

Analysis of electroencephalographic recordings (EEG) often requires the solution of a forward problem, where the scalp potentials created by a known source are determined. Most current solution methods are based on the Geselowitz formulation that solves a boundary integral equation for the potential. We show that the problem can also be reformulated as an integral equation for the accumulated charge at the interfaces between regions of homogeneous conductivity. In contrast to the Geselowitz formulation, the resulting equations have a unique solution and their solution does not require deflation steps.