تفاوت مغز و اعصاب تشریحی در میان بیماران آشناپنداری مبتلا به صرع و غیرصرع

Objective 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. Methods 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. Results 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. Conclusions 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.

éjà vu (DV) is a transitory mental state of incongruous impression of familiarity of present experience with an undefined past. Although almost 80% of healthy individuals have experienced DV at once in their lives (Brázdil et al., 2012), this fascinating phenomenon is also very often present in patients with mesial temporal lobe epilepsy (MTLE) mainly with familial trend (Gambardella et al., 2000). To date, it is already very well known that epileptic illusions of DV are ictal manifestations arising from discharge within either mesial or lateral temporal cortex (Bancaud, Brunet-Bourgin, Chauvel, & Halgren, 1994) whereas anatomical basis for DV in healthy subjects is less delineated and interpreted. Very recently, Brazdil and coworkers (Brázdil et al., 2012) described for the first time the anatomical correlates associated with DV in healthy population, illustrating volumetric differences in several brain regions involving predominantly mesio-temporal regions where the loss of gray matter was significant. Very interestingly, the present author found the same well-known epileptic network (Hippocampus-Thamalus-Basal Ganglia) involved in the genesis of refractory MTLE together with critical brain areas involved in the limbic system (Amygdala, Orbitofrontal cortex and insular cortex) (Bonilha et al., 2004, Catani et al., 2012 and Labate et al., 2010). These epileptic networks have also been extensively described in patients with milder form of sporadic MTLE called benign MTLE (bMTLE), which is characterized by seizure onset in adulthood, frequent familial history and simple partial epileptic DV that often represents the only predominant ictal symptom (Labate et al., 2010, Labate et al., 2008 and Labate et al., 2011).

This is the first study that addressed potential neuro-anatomical differences related to the experience of DV in bMTLE and healthy individuals. We decided to study individuals with sporadic bMTLE because of its peculiarity being patients with a very benign clinical course that may suffer from simple partial DV sometimes in life as unique epileptic symptom (Labate et al., 2011). Indeed, bMTLE syndrome represents a mild type of temporal lobe epilepsy that shares very close similitude with healthy subjects experiencing DV as recently described by some authors (Brázdil et al., 2012). Specifically, we found that bMTLE patients with DV were characterized by increased gray matter volume of the left mesio-temporal region, involving the parahippocampal gyrus and the hippocampus, together with the left visual cortex (calcarine regions), when compared with bMTLE patients without DV. When we compared healthy controls experiencing or not DV, we found that control individuals with DV were characterized by reduced gray matter volume in the left insular cortex.