Application of particle swarm optimization in epileptic spike EEG source localization

Surgical therapy has become an important therapeutic alternative for patients with medically intractable epilepsy. Correct and anatomically precise localization of an epileptic focus is essential to decide if resection of brain tissue is possible. The inverse problem in EEG-based source localization is to determine the location of the brain sources that are responsible for the measured potentials at the scalp electrodes. We propose a new global optimization method based on particle swarm optimization (PSO) to solve the epileptic spike EEG source localization inverse problem. In a forward problem a modified subtraction method is proposed to reduce the computational time. The good accuracy and fast convergence are demonstrated for 2D and 3D cases with realistic head models. The results from the new method are promising for use in the pre-surgical clinic in the future.

The spike and background dipole positions and orientations in the 3D case (black arrow: spike dipole; red arrow: background dipole). Figure optionsDownload as PowerPoint slideHighlights
► Modified particle swarm optimization can find the optimal solution significantly faster and more accurate than the standard PSO.
► Modified particle swarm optimization reduces the probability of trapping in local minima.
► Modified subtraction method speeds up the computational time.