title: Changes in intracortical excitability after transient ischemic attack are associated with ABCD² score.
abstract: OBJECTIVE
  A transient ischemic attack (TIA) is a brief ischemic episode characterized by rapid clinical resolution and not associated with permanent cerebral infarction. Whether changes in intracortical excitability persist and are related to clinical predictors of stroke risk after TIA remains unknown.
  
  
  METHODS
  Participants were individuals with clinically resolved motor TIA with no structural lesions and healthy age-matched control participants. Single and paired-pulse transcranial magnetic stimulation was used to measure intracortical excitability. Recruitment curves for percent inhibition and facilitation were used to derive excitability thresholds. Correlations between threshold asymmetries and ABCD(2) score were performed.
  
  
  RESULTS
  Results showed a significant 3-way interaction with reduced inhibition and enhanced facilitation in the affected compared with unaffected hemisphere after TIA. No significant differences were present in healthy participants. Asymmetries in intracortical inhibition and facilitation were significantly correlated with ABCD(2) score.
  
  
  CONCLUSIONS
  The present study is the first, to our knowledge, to demonstrate altered intracortical inhibition and facilitation in the affected hemisphere after TIA. These changes occurred on average 2 weeks after clinical signs of TIA resolved and in the absence of structural lesions and were not present in healthy age-matched control participants. Furthermore, this study is the first, to our knowledge, to report that changes in intracortical excitability after TIA are associated with ABCD(2) score.
authors.affiliation: School of Population and Public Health, University of British Columbia, 217-2277 Wesbrook Mall, Vancouver, British Columbia V6T 2B5 Canada.
authors.forename: Jodi D
authors.initials: JD
authors.lastname: Edwards
authors.forename: Sean K
authors.initials: SK
authors.lastname: Meehan
authors.forename: Adrian R
authors.initials: AR
authors.lastname: Levy
authors.forename: Philip A
authors.initials: PA
authors.lastname: Teal
authors.forename: Meghan A
authors.initials: MA
authors.lastname: Linsdell
authors.forename: Lara A
authors.initials: LA
authors.lastname: Boyd
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000503:physiopathology*; D006801:Humans; D002546:Ischemic Attack, Transient / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D020521:Stroke / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology