title: Executive functions and intraindividual variability following concussion.
abstract: The long-term outcomes of executive functions and intraindividual variability (IIV; i.e., trial-to-trial or across-task variability in cognitive performance) following concussion are unclear due to inconsistent and limited research findings, respectively.
  
  
  OBJECTIVE
  Responding to these gaps in scientific understanding, the current study aimed to assess the utility of both executive functions and IIV at predicting concussion history.
  
  
  METHODS
  Altogether 138 self-identified athletes (Mage = 19.9 ± 1.91 years, 60.8% female, 19.6% with one concussion, 18.1% with two or more concussions) completed three executive-related cognitive tasks (i.e., n-back, go/no-go, global-local). Ordinal logistic regression analyses examined the joint effect of person-mean and IIV as predictors of concussion status.
  
  
  RESULTS
  Only mean response time for the global-local task predicted the number of past concussions, while no IIV variables reached unique significance.
  
  
  CONCLUSIONS
  IIV research on concussion remains limited; however, the preliminary results do not indicate any additional value of IIV indices above mean performances at predicting past concussion. For executive functions, shifting appears most sensitive at detecting concussion group differences, with past researchers identifying post concussion impairment in attentional processing.
authors.affiliation: a Department of Psychology , University of Victoria , Victoria , BC , Canada.
authors.forename: Justin E
authors.initials: JE
authors.lastname: Karr
authors.forename: Mauricio A
authors.initials: MA
authors.lastname: Garcia-Barrera
authors.forename: Corson N
authors.initials: CN
authors.lastname: Areshenkoff
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes / Q000523:psychology; D001265:Athletic Injuries / Q000503:physiopathology; D001924:Brain Concussion / Q000503:physiopathology*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D007206:Individuality; D008297:Male; D009483:Neuropsychological Tests; D013647:Task Performance and Analysis; D055815:Young Adult