A new algorithm for estimating scalp laplacian EEG and its application to visual-evoked potentials

This paper presents a new method to estimate the scalp Laplacian EEG from scalp potentials on a realistic geometry scalp surface. The mathematical potential distribution on the realistically shaped scalp is constructed using a three-dimensional spline, and the mathematical scalp geometry model is constructed using a two-dimensional spline. The performance of the proposed method is evaluated by computer simulations using the three-concentric-sphere head model. The feasibility of the present method has also been tested in visual-evoked potentials recorded in a human subject. The present simulation and experimental data suggest that the proposed method provides an alternative to estimating the surface Laplacian from potentials over a realistic-geometry scalp.