title: Age at stroke determines post-stroke language lateralization.
abstract: OBJECTIVE
  To determine how age at the time of left middle cerebral artery stroke affects language lateralization in a combined sample of subjects with perinatal, childhood, and adult stroke.
  
  
  METHODS
  19 participants who had perinatal stroke (<1 month of age), 32 with later stroke, and 51 sex-/age-matched healthy controls (HCs) received fMRI of language using verb generation task (VGT).
  
  
  RESULTS
  Percent lesion volumes were not different between groups (perinatal vs. late stroke) when taking brain volume into account (p = 0.084). Perinatal stroke group showed bilateral signal increases compared to more left-lateralized signals in matched HCs; late stroke group and HCs both showed left-hemispheric signal increases. LIs in the stroke groups were consistently more bilateral than in HCs (all p < 0.008) except for the late group's posterior LI (p = 0.080). There was greater proportion of leftward language lateralization in HCs compared to their respective stroke groups (78.9% vs. 31.6% in perinatal; 87.5% vs. 59.4% in late stroke; p = 0.004) and a larger proportion of leftward lateralization in late compared to perinatal stroke (p = 0.039). The age of stroke occurrence showed significant positive associations with global and frontal LI (both p ≤ 0.007).
  
  
  CONCLUSIONS
  As expected, the age of stroke occurrence affects subsequent verb generation lateralization. Greater cortical plasticity is observed in earlier stroke while later stroke is associated with reliance on the repair of the previously damaged left-hemispheric networks.
authors.affiliation: Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Szaflarski
authors.affiliation: Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Allendorfer
authors.affiliation: Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: A W
authors.initials: AW
authors.lastname: Byars
authors.affiliation: Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: J
authors.initials: J
authors.lastname: Vannest
authors.affiliation: Department of Communication Sciences and Disorders, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: A
authors.initials: A
authors.lastname: Dietz
authors.affiliation: Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Hernando
authors.affiliation: Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Holland
mesh_terms: D000375:Aging / Q000473:pathology / Q000502:physiology*; D001921:Brain / Q000254:growth & development / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology / Q000503:physiopathology*; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009929:Organ Size
keywords: adult; aphasia; child; fMRI; language; language lateralization; stroke