title: Asymmetric Gray Matter Volume Changes Associated with Epilepsy Duration and Seizure Frequency in Temporal-Lobe-Epilepsy Patients with Favorable Surgical Outcome.
abstract: OBJECTIVE
  This study aimed to estimate the changes in gray matter volume (GMV) and their hemispheric difference in patients with mesial temporal lobe epilepsy (MTLE) using a voxel-based morphometry (VBM) methodology, and to determine whether GMV changes are correlated with clinical features.
  
  
  METHODS
  VBM analysis of brain MRI using statistical parametric mapping 8 (SPM8) was performed for 30 left MTLE (LMTLE) and 30 right MTLE (RMTLE) patients and 30 age- and sex-matched healthy controls. We also analyzed the correlations between GMV changes and clinical features of MTLE patients.
  
  
  RESULTS
  In SPM8-based analyses, MTLE patients showed significant GMV reductions in the hippocampus ipsilateral to the epileptic focus, bilateral thalamus, and contralateral putamen in LMTLE patients. The GMV reductions were more extensive in the ipsilateral hippocampus, thalamus, caudate, putamen, uncus, insula, inferior temporal gyrus, middle occipital gyrus, cerebellum, and paracentral lobule in RMTLE patients. These patients also exhibited notable reductions of GMV in the contralateral hippocampus, thalamus, caudate, putamen, and inferior frontal gyrus. We observed that GMV reduction was positively correlated with several clinical features (epilepsy duration and seizure frequency in RMTLE, and history of febrile seizure in LMTLE) and negatively correlated with seizure onset age in both the RMTLE and LMTLE groups.
  
  
  CONCLUSIONS
  Our study revealed GMV decreases in the hippocampus and extrahippocampal regions. Furthermore, the GMV reduction was more extensive in the RMTLE group than in the LMTLE group, since it included the contralateral hemisphere in the former. This difference in the GMV reduction patterns between LMTLE and RMTLE may be related to a longer epilepsy duration and higher seizure frequency in the latter.
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Korea.|Samsung Biomedical Research Institute (SBRI), Seoul, Korea.
authors.forename: Jeong Sik
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Neurology, Seoul National University Boramae Hospital, Seoul, Korea.
authors.forename: Dae Lim
authors.initials: DL
authors.lastname: Koo
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Korea.|Samsung Biomedical Research Institute (SBRI), Seoul, Korea.
authors.forename: Eun Yeon
authors.initials: EY
authors.lastname: Joo
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunwan University School of Medicine, Seoul, Korea.
authors.forename: Sung Tae
authors.initials: ST
authors.lastname: Kim
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Korea.|Samsung Biomedical Research Institute (SBRI), Seoul, Korea.
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Seo
authors.affiliation: Department of Neurology, Neuroscience Center, Samsung Medical Center and Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul, Korea.|Samsung Biomedical Research Institute (SBRI), Seoul, Korea. sbhong@skku.edu.
authors.forename: Seung Bong
authors.initials: SB
authors.lastname: Hong
keywords: gray matter volume; hippocampal sclerosis; magnetic resonance imaging; mesial temporal lobe epilepsy; voxel-based morphometry