title: MRI analysis in temporal lobe epilepsy: cortical thinning and white matter disruptions are related to side of seizure onset.
abstract: OBJECTIVE
  Past studies reported more widespread structural brain abnormalities in patients with left compared to right temporal lobe epilepsy (TLE), but the profile of these differences remains unknown. This study investigated the relationship between cortical thinning, white matter compromise, epilepsy variables, and the side of seizure onset, in patients with TLE.
  
  
  METHODS
  We performed diffusion tensor imaging tractography and cortical thickness analyses of 18 patients with left TLE (LTLE), 18 patients with right TLE (RTLE), and 36 controls. We investigated the relationship among brain structural abnormalities, side of seizure onset, age of seizure onset, and disease duration.
  
  
  RESULTS
  Patients with TLE displayed cortical thinning and white matter compromise, predominately on the side ipsilateral to the seizure onset. Relative to RTLE, patients with LTLE showed more widespread abnormalities, particularly in white matter fiber tracts. Greater compromise in white matter integrity was associated with earlier age of seizure onset, whereas cortical thinning was marginally associated with disease duration.
  
  
  CONCLUSIONS
  These data support previous findings of LTLE showing greater structural compromise than RTLE, and suggest that mechanisms may not be uniform for gray and white matter compromise in patients with LTLE and RTLE. These results may indicate that LTLE is different from RTLE, possibly due to greater vulnerability of the left hemisphere to early injury and the progressive effects of seizures.
authors.affiliation: Department of Psychiatry, University of California, San Diego, California, USA. nkemmotsu@ucsd.edu
authors.forename: Nobuko
authors.initials: N
authors.lastname: Kemmotsu
authors.forename: Holly M
authors.initials: HM
authors.lastname: Girard
authors.forename: Boris C
authors.initials: BC
authors.lastname: Bernhardt
authors.forename: Leonardo
authors.initials: L
authors.lastname: Bonilha
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Lin
authors.forename: Evelyn S
authors.initials: ES
authors.lastname: Tecoma
authors.forename: Vicente J
authors.initials: VJ
authors.lastname: Iragui
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Hagler
authors.forename: Eric
authors.initials: E
authors.lastname: Halgren
authors.forename: Carrie R
authors.initials: CR
authors.lastname: McDonald
mesh_terms: D000328:Adult; D017668:Age of Onset; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D012044:Regression Analysis