Particle Swarm Optimization Applied to EEG Source Localization of Somatosensory Evoked Potentials

• Published in: IEEE transactions on neural systems and rehabilitation engineering Vol. 22; no. 1; pp. 11 - 20
• Main Authors: Shirvany, Yazdan, Mahmood, Qaiser, Edelvik, Fredrik, Jakobsson, Stefan, Hedstrom, Anders, Persson, Mikael
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.2014
• Subjects: Algorithms; Brain Mapping - methods; Brain modeling; Computer Simulation; CORTEX; DIPOLE LOCALIZATION; Electric potential; ELECTRICAL-STIMULATION; Electrodes; Electroencephalogram (EEG) source localization; Electroencephalography; Electroencephalography - methods; Epilepsy; Evoked Potentials, Somatosensory - physiology; finite element method (FEM); FINITE-ELEMENT-METHOD; FUNCTIONAL MRI; HEAD MODELS; Humans; inverse problem; Inverse problems; magnetic resonance imaging (MRI); MEDIAN NERVE-STIMULATION; Models, Neurological; Nerve Net - physiology; Particle swarm optimization; RECONSTRUCTION; Reproducibility of Results; Sensitivity and Specificity; Somatosensory Cortex - physiology; somatosensory evoked potential (SEP); subtraction method
• ISSN: 1534-4320; 1558-0210; 1558-0210
• DOI: 10.1109/TNSRE.2013.2281435

One of the most important steps in presurgical diagnosis of medically intractable epilepsy is to find the precise location of the epileptogenic foci. Electroencephalography (EEG) is a noninvasive tool commonly used at epilepsy surgery centers for presurgical diagnosis. In this paper, a modified particle swarm optimization (MPSO) method is used to solve the EEG source localization problem. The method is applied to noninvasive EEG recording of somatosensory evoked potentials (SEPs) for a healthy subject. A 1 mm hexahedra finite element volume conductor model of the subject's head was generated using T1-weighted magnetic resonance imaging data. Special consideration was made to accurately model the skull and cerebrospinal fluid. An exhaustive search pattern and the MPSO method were then applied to the peak of the averaged SEP data and both identified the same region of the somatosensory cortex as the location of the SEP source. A clinical expert independently identified the expected source location, further corroborating the source analysis methods. The MPSO converged to the global minima with significantly lower computational complexity compared to the exhaustive search method that required almost 3700 times more evaluations.