title: Cortical Alterations in Medication-Overuse Headache.
abstract: OBJECTIVE
  Using surface-based morphometry we aimed to provide a detailed examination of cortical alterations in medication-overuse headache (MOH), by disentangling between altered cortical thickness and gyrification (folding).
  
  
  BACKGROUND
  In MOH, pain modulation is probably dysfunctional at the cortical and subcortical level, resulting in a disequilibrium between pain inhibition and facilitation. Both increased and decreased cortical volumes have been reported in individuals with MOH. There is however no detailed examination to date that distinguishes between altered cortical thickness and gyrification. Such distinction would help to identify the nature and timing of neurodevelopmental mechanisms at play in affected individuals.
  
  
  METHODS
  We investigated cortical thickness and gyrification in 29 patients with MOH according to International Headache Society criteria and 29 age- and gender-matched controls, using high-resolution structural MRIs of the brain analyzed with FreeSurfer. This is a secondary analysis of data from a previously published voxel-based morphometry study.
  
  
  RESULTS
  In patients with MOH compared to controls, reduced cortical thickness was observed in the left prefrontal cortex. We also observed higher local gyrification in one cluster extending from the fusiform cortex to adjacent medial temporal regions, and in another cluster in the right occipital pole. Higher gyrification in the right occipital pole predicted poor response after detoxification.
  
  
  CONCLUSIONS
  Corroborating previous volumetric results, our study adds information on the putative neurobiological mechanisms involved in MOH, suggesting neurodevelopmental changes in MOH.
authors.affiliation: Neurological Center Rosenhuegel and Karl Landsteiner Institute for Epilepsy Research and Cognitive Neurology, Vienna, Austria.|Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, Zurich, CH-8091, Switzerland.
authors.forename: Franz
authors.initials: F
authors.lastname: Riederer
authors.affiliation: Stanford Cognitive & Systems Neuroscience Laboratory, Stanford, Palo Alto, CA, USA.|Office Médico-Pédagogique, University of Geneva, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: Schaer
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, Zurich, CH-8091, Switzerland.|Rehaclinic Bad Zurzach, Zurzach, Switzerland.
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Gantenbein
authors.affiliation: Institute for Biomedical Engineering, Swiss Federal Institute of Technology and the University of Zurich, Zurich, Switzerland.
authors.forename: Roger
authors.initials: R
authors.lastname: Luechinger
authors.affiliation: Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Lars
authors.initials: L
authors.lastname: Michels
authors.affiliation: Department of Childhood and Adolescent Psychiatry, Medical University of Vienna, Währinger, Vienna.
authors.forename: Marihan
authors.initials: M
authors.lastname: Kaya
authors.affiliation: Institute of Neuroradiology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Kollias
authors.affiliation: Rehaclinic Bad Zurzach, Zurzach, Switzerland.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Sándor
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000000981:diagnostic imaging*; D005260:Female; D051271:Headache Disorders, Secondary / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size
keywords: cortical thickness; local gyrification index; medication-overuse headache; treatment response