Temporal plus epilepsy: a review

Abstract

Temporal plus epilepsy is defined as focal epilepsy in which the primary epileptogenic area extends beyond the temporal lobe. It involves the neighboring regions such as the insula, the suprasilvian opercular cortex, the orbitofrontal cortex and the temporo-parieto-occipital junction. The objective of this review is to provide an update in temporal plus epilepsy. A previous history of brain trauma, a history of tonic clonic seizures, and previous central nervous system infection are risk factors. They likely allowed the generation of complex hippocampal and extrahypocampic neural networks. Clinical manifestations will depend on the location of the epileptogenic zone as well as the rapid propagation into temporal mesial structures. Video-electroencephalography usually shows involvement of the temporal lobe, with rapid propagation into the perisilvian, orbitofrontal or temporo-parieto-occipital regions. The magnetoelectroencephaography has lesser muscle contamination and could be considered as a biomarker of early states in the diagnosis process. Brain MRI is usually negative or shows non-specific mesial temporal abnormalities. Stereoelectroencephalography is the invasive method of choice. Temporal plus epilepsy is considered to be the most common cause of temporal lobe epilepsy surgery failure and represents up to 30%.