P.007 Déjà vu evoked by stimulating the insula in two patients suffering from intractable temporal lobe epilepsy

Abstract

Background: Déjà vu is a common manifestation of temporal lobe seizures. It can be reproduced by electrical stimulation of the hippocampus, amygdala and temporal neocortex with stereotactically implanted electrodes. We report here déjà vu triggered by the stimulation of the insula. Methods: Two patients suffering from intractable temporal lobe epilepsy exhibiting auras of déjà vu underwent invasive EEG studies. One patient had a prior temporal lobectomy with reoccurrence of similar symptoms after surgery. We performed functional connectivity analyses using phase locking value (PLV) to estimate changes in connectivity between different brain regions in the standard EEG frequency bands during stimulation. Results: Stimulation of the insular cortex induced reproducible déjà vu symptoms in both patients. In one patient, PLV analysis showed increased synchronization in the alpha band between insular and temporal regions after an evoked déjà vu compared to a control stimulation. Conclusions: Our results suggest that the insula may in rare occasions generate déjà vu. This implies that insular epileptogenicity cannot be ruled out in patients exhibiting such an aura nor in patients with persisting déjà vu despite an initial amygdalo-hippocampectomy.