Source analysis of lesional frontal-lobe epilepsy

Patients with frontal-lobe epilepsy comprise the second largest group undergoing epilepsy surgery. It has been reported that the difficulty in localizing the epileptogenic zone in these patients is due to the rapid spread of the epileptiform activity within the frontal lobe and to adjoining regions of the brain. We formulated the question of whether the functional localization of dynamic sources of interictal activity in patients with well-defined frontal lesions would yield clear evidence regarding both the topology of the primary sources in relation to the epileptogenic lesion and the pattern of spread of the epileptiform activity throughout the brain. In order to achieve this, we used high-resolution EEG recordings combined with MRI, and advanced source-reconstruction algorithms. In this article, the source-imaging procedures used will be discussed extensively, based on one exemplary patient with complex partial FLE.