OBJECTIVE: The aim of this study was to assess clinical and electrophysiological differences within a group of patients with magnetic-resonance-imaging-negative temporal lobe epilepsy (MRI-negative TLE) according to seizure onset zone (SOZ) localization in invasive EEG (IEEG). METHODS: According to SOZ localization in IEEG, 20 patients with MRI-negative TLE were divided into either having mesial SOZ-mesial MRI-negative TLE or neocortical SOZ-neocortical MRI-negative TLE. We evaluated for differences between these groups in demographic data, localization of interictal epileptiform discharges (IEDs), and the ictal onset pattern in semiinvasive EEG and in ictal semiology. RESULTS: Thirteen of the 20 patients (65%) had mesial MRI-negative TLE and 7 of the 20 patients (35%) had neocortical MRI-negative TLE. The differences between mesial MRI-negative TLE and neocortical MRI-negative TLE were identified in the distribution of IEDs and in the ictal onset pattern in semiinvasive EEG. The patients with neocortical MRI-negative TLE tended to have more IEDs localized outside the anterotemporal region (p=0.031) and more seizures without clear lateralization of ictal activity (p=0.044). No other differences regarding demographic data, seizure semiology, surgical outcome, or histopathological findings were found. CONCLUSIONS: According to the localization of the SOZ, MRI-negative TLE had two subgroups: mesial MRI-negative TLE and neocortical MRI-negative TLE. The groups could be partially distinguished by an analysis of their noninvasive data (distribution of IEDs and lateralization of ictal activity). This differentiation might have an impact on the surgical approach.

• MeSH
• Child MeSH
• Adult MeSH
• Electroencephalography MeSH
• Epilepsy, Temporal Lobe diagnostic imaging   surgery   MeSH
• Fluorodeoxyglucose F18 MeSH
• Infant MeSH
• Humans MeSH
• Magnetic Resonance Imaging methods   MeSH
• Adolescent MeSH
• Young Adult MeSH
• Brain diagnostic imaging   MeSH
• Neocortex diagnostic imaging   MeSH
• Neurosurgical Procedures MeSH
• Positron-Emission Tomography MeSH
• Child, Preschool MeSH
• Radiopharmaceuticals MeSH
• Retrospective Studies MeSH
• Temporal Lobe diagnostic imaging   MeSH
• Age of Onset MeSH
• Treatment Outcome MeSH
• Seizures diagnostic imaging   physiopathology   MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Infant MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Child, Preschool MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

PURPOSE: The purpose of the study was to evaluate cerebral morphological changes in temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) and their relationship to the cerebellum. METHODS: The study cohort included 21 patients with intractable TLE-HS (14 left-sided, 7 right-sided) and 38 healthy controls (HC). All patients later underwent anteromedial temporal lobe resection. All subjects were examined using a 1.5-T magnetic resonance imaging (MRI). Volumes of distinct cerebral and cerebellar structures were measured using voxel-based morphometry. The structural covariance of temporal lobe structures, insula, and thalamus with cerebellar substructures was examined using partial least squares regression. RESULTS: Morphological changes were more significant in the group with left TLE-HS when comparing left-sided with right-sided structures as well as when comparing patients with controls. The gray matter volume (GMV) of the temporal lobe structures was smaller ipsilaterally to the seizure onset side in most cases. There was a significant amygdala enlargement contralateral to the side of hippocampal sclerosis in both patients with right and left TLE-HS as compared with controls. Selected vermian structures in patients with left but not right TLE-HS had significantly larger GMV than the identical substructures in controls. The structural covariance differed significantly between patients with left and right TLE-HS as compared with HC. The analysis revealed significant negative covariance between anterior vermis and mesial temporal structures in the group with left TLE-HS. No significance was observed for the group with right TLE-HS. CONCLUSION: There is significant asymmetry in the GMV of cerebral and cerebellar structures in patients with TLE-HS. Morphological changes are distinctly more pronounced in patients with left TLE-HS. The observed structural covariance between the cerebellum and supratentorial structures in TLE-HS suggests associations beyond the mesial temporal lobe structures and thalamus.

• MeSH
• Adult MeSH
• Epilepsy, Temporal Lobe diagnostic imaging   surgery   MeSH
• Hippocampus diagnostic imaging   MeSH
• Cohort Studies MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging methods   MeSH
• Adolescent MeSH
• Young Adult MeSH
• Cerebellum diagnostic imaging   MeSH
• Cerebral Cortex diagnostic imaging   MeSH
• Gray Matter diagnostic imaging   MeSH
• Sclerosis diagnostic imaging   surgery   MeSH
• Temporal Lobe diagnostic imaging   surgery   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH