SEEG recording of a patient with very localized insular onset and subsequent insular resection. A, The SEEG study was focused on the right insulo-opercular region with additional electrodes sampling the right temporal and frontal lobes and the left insular and temporal regions. B, SEEG activity at seizure onset (upper panel) exhibits spikes and polyspike discharges quickly followed by a low-voltage fast activity in the superior part of the anterior long gyrus of the right insula (R Ins) that spreads to the right opercular cortex (R Op). Note the almost immediate involvement of the contralateral insula (L Ins). The patient describes a painful tingling sensation in the left hand and then (lower panel) loses contact and presents temporal-like symptoms when the seizure spread to the right mesiotemporal lobe (R mT), anteroinferior part of the insula (R Ins), and lateral temporal cortex (lT). The orbitofrontal cortex (Of) is spared. C, Schematic representation of the insular contacts involved in seizure onset before spreading to extrainsular regions. D, Epileptogenicity map indicating the highest value of activation in the 60- to 100-Hz frequency band at seizure onset. E, Tailored resection of the right anterior long insular gyrus. Postoperatively, there was transient dysgeusia that resolved completely. The patient has been seizure free without medication for 6 years. Pathological examination revealed a focal cortical dysplasia type IB. SEEG indicates stereo electroencephalogram.