Neuro-anatomical differences among epileptic and non-epileptic déjà-vu

Dèjà-vù (DV) can occur as a seizure of mesial temporal lobe epilepsy (MTLE) and in almost 80% of healthy individuals. The remarkable similarity between epileptic DV and DV in healthy individuals raises the possibility that DV might sometimes be an ictal phenomenon in apparently normal individuals. Thus, we studied a group of healthy subjects versus individuals with benign MTLE (bMTLE) both experiencing DV.

63 individuals with epilepsy patients with bMTLE and 39 healthy controls at Catanzaro University were recruited. Participants completed the Inventory for Déjà Vu (DV) Experiences Assessment (IDEA) test, underwent awake and asleep electroencephalogram, MRI of the brain using a 3T scanner and whole brain voxel-based morphometry (VBM). bMTLE patients with DV and without DV were also matched for the presence of hippocampal sclerosis.

Our controls had no history of neurological or psychiatric illness, epilepsy or history of febrile convulsions. Neurological and cognitive examinations were normal. Electroencephalographic procedures were unremarkable in all controls. In bMTLE group, the direct comparison of VBM between individuals with epilepsy with DV versus those without DV revealed abnormal anatomical changes in the left hippocampus, parahippocampal gyrus and visual cortex. The VBM of healthy controls with DV showed abnormal anatomical changes only in the left insular cortex.

Our VBM results demonstrated different morphologic patterns in individuals with epilepsy and control subjects experiencing DV, involving the memory circuit in bMTLE patients and cerebral regions in the emotional network in healthy controls.