New topographic mapping of temporal lobe seizures

A unique topographic map has been developed based on EEG data of ictal events originating from the basal/mesiotemporal lobe regions. This technique involves a new mapping method of temporal lobe seizures as opposed to the interictal activity maps of most commercially available software. The map integrates data from sphenoidal electrodes as well as the standard 10-20 surface electrodes recorded with bipolar montages. A basal view is ideal for visualization of onset of temporal lobe ictal discharges recorded with chronic sphenoidal electrodes. We used the last 150 ictal events from 40 patients with basal/mediotemporal lobe epilepsy to develop this technique. Results indicate that a topographic view incorporating sphenoidal and scalp electrodes may provide a useful adjunct for interpretation of EEG recordings and a basis for comparison between and among patient groups for both ictal and interictal epileptic discharges.