title: Abnormal cortical thickness connectivity persists in childhood absence epilepsy.
abstract: OBJECTIVE
  Childhood absence epilepsy (CAE) is a childhood-onset generalized epilepsy. Recent fMRI studies have suggested that frontal cortex activity occurs before thalamic involvement in epileptic discharges suggesting that frontal cortex may play an important role in childhood absence seizures. Neurocognitive deficits can persist after resolution of the epilepsy. We investigate whether structural connectivity changes are present in the brains of CAE patients in young adulthood.
  
  
  METHODS
  Cortical thickness measurements were obtained for 30 subjects with CAE (mean age 21 ± 2 years) and 56 healthy controls (mean age 24 ± 4) and regressed for age, sex, and total intracranial volume (TIV). Structural connectivity was evaluated by measuring the correlation between average cortical thicknesses in 915 regions over the brain. Maps of connectivity strength were then obtained for both groups.
  
  
  RESULTS
  When compared to controls, the CAE group shows overall increased "connectivity" with focal increased connection strength in anterior regions including; the anterior cingulate and the insula and superior temporal gyrus bilaterally; the right orbito-frontal and supramarginal regions; and the left entorhinal cortex. Decreased connection strength in the CAE group was found in the left occipital lobe, with a similar trend in right occipital lobe.
  
  
  CONCLUSIONS
  Brains in young adults whose CAE was resolved had abnormal structural connectivity. Our findings suggest that frontal regions correlate most with cortical thickness throughout the brain in CAE patients, whereas occipital regions correlate most in well matched normal controls. We interpret this as evidence of a developmental difference in CAE that emphasizes these frontal lobe regions, perhaps driven by frontal lobe epileptiform activity.
authors.affiliation: The Florey Institute of Neuroscience and Mental Health Austin Campus, Heidelberg, Victoria, Australia.
authors.forename: Evan K
authors.initials: EK
authors.lastname: Curwood
authors.affiliation: Florey Department of Neuroscience and Mental Health, The University of Melbourne Heidelberg, Victoria, Australia.
authors.forename: Mangor
authors.initials: M
authors.lastname: Pedersen
authors.affiliation: The Florey Institute of Neuroscience and Mental Health Austin Campus, Heidelberg, Victoria, Australia ; Department of Medicine, The University of Melbourne Parkville, Victoria, Australia.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Carney
authors.affiliation: Epilepsy Center, Ann and Robert H. Lurie Children's Hospital of Chicago Chicago, Illinois.
authors.forename: Anne T
authors.initials: AT
authors.lastname: Berg
authors.affiliation: The Florey Institute of Neuroscience and Mental Health Austin Campus, Heidelberg, Victoria, Australia ; Florey Department of Neuroscience and Mental Health, The University of Melbourne Heidelberg, Victoria, Australia ; Department of Medicine, The University of Melbourne Parkville, Victoria, Australia.
authors.forename: David F
authors.initials: DF
authors.lastname: Abbott
authors.affiliation: The Florey Institute of Neuroscience and Mental Health Austin Campus, Heidelberg, Victoria, Australia ; Florey Department of Neuroscience and Mental Health, The University of Melbourne Heidelberg, Victoria, Australia ; Department of Medicine, The University of Melbourne Parkville, Victoria, Australia.
authors.forename: Graeme D
authors.initials: GD
authors.lastname: Jackson