Epileptic source localization using wavelet prefiltering and MUSIC scanning

The epileptic focus localization in the 3-D brain structure is performed using integer spline wavelet prefiltering and source localization. The forward and inverse problems are solved by Boundary Element Method (BEM) and MUSIC (Multiple Signal Classification) Scanning algorithm, respectively. The realistic head model is obtained by using an average human MRI data released by the Montreal Neurological Institute (MNI). 19 Channel EEG data from three different patients are collected. The technique is tested on these three clinical cases with secondary epileptic seizures based on morphological lesions that could be depicted in the anatomical MRI examinations of the patients. The estimated locations of the generators of interictal epileptiform signals correspond well to the surrounding neural tissue of the lesions. Especially, the disappearance of the seizures in two operated patients after the removal of the astrocytomas verifies the results. The wavelet prefiltering facilitates the visual inspection and detection of the interictal epileptic spikes and the BEM based on a realistic head model gives a more accurate anatomical localization for the focus. A focal source model is widely accepted in many cases of epilepsy and the MUSIC scanning seems to be very suitable for localizing these type of sources.