title: Preservation of structural brain network hubs is associated with less severe post-stroke aphasia.
abstract: OBJECTIVE
  Post-stroke aphasia is typically associated with ischemic damage to cortical areas or with loss of connectivity among spared brain regions. It remains unclear whether the participation of spared brain regions as networks hubs affects the severity of aphasia.
  
  
  METHODS
  We evaluated language performance and magnetic resonance imaging from 44 participants with chronic aphasia post-stroke. The individual structural brain connectomes were constructed from diffusion tensor. Hub regions were defined in accordance with the rich club classification and studied in relation with language performance.
  
  
  RESULTS
  Number of remaining left hemisphere rich club nodes was associated with aphasia, including comprehension, repetition and naming sub-scores. Importantly, among participants with relative preservation of regions of interest for language, aphasia severity was lessened if the region was not only spared, but also participated in the remaining network as a rich club node: Brodmann area (BA) 44/45 - repetition (p = 0.009), BA 39 - repetition (p = 0.045) and naming (p <  0.01), BA 37 - fluency (p <  0.001), comprehension (p = 0.025), repetition (p <  0.001) and naming (p <  0.001).
  
  
  CONCLUSIONS
  Disruption of language network structural hubs is directly associated with aphasia severity after stroke.
authors.affiliation: Department of Neurology, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Gleichgerrcht
authors.forename: Madison
authors.initials: M
authors.lastname: Kocher
authors.forename: Travis
authors.initials: T
authors.lastname: Nesland
authors.affiliation: Department of Psychology, University of South Carolina, Columbia, SC, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Rorden
authors.affiliation: Department of Communications Sciences and Disorders, University of South Carolina, Columbia, SC, USA.
authors.forename: Julius
authors.initials: J
authors.lastname: Fridriksson
authors.affiliation: Department of Neurology, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Bonilha
mesh_terms: D001037:Aphasia / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000150:complications / Q000473:pathology / Q000503:physiopathology / Q000523:psychology; D015331:Cohort Studies; D063132:Connectome; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology; D020521:Stroke / Q000150:complications* / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology
keywords: Connectome; aphasia; diffusion tensor imaging; hubs; language performance; magnetic resonance imaging; rich club; stroke; structural networks