STL: a spatio-temporal characterization of focal interictal events.

An innovative method for on-line processing of array ECoG data, the Spatio-Temporal Laplacian, intended for intraoperative epileptic focus localization is presented. This method simultaneously involves the spatial and temporal characteristics of the potential field manifestations peculiar to focal interictal events. A 3-Dimensional (x, y and t) sample space is used to explain and apply the Spatio-Temporal Laplacian (STL) transformation. In particular, a focal interictal event is detected through the coincident spatial and temporal sharpness that it introduces in this sample space. Preliminary results from two subjects are presented and compared with standard bioplar derivation signals, traditionally used in the focus localization task.