title: ImPact test-retest reliability: reliably unreliable?
abstract: BACKGROUND
  Computerized neuropsychological testing is commonly used in the assessment and management of sport-related concussion. Even though computerized testing is widespread, psychometric evidence for test-retest reliability is somewhat limited. Additional evidence for test-retest reliability is needed to optimize clinical decision making after concussion.
  
  
  OBJECTIVE
  To document test-retest reliability for a commercially available computerized neuropsychological test battery (ImPACT) using 2 different clinically relevant time intervals.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Two research laboratories.
  
  
  METHODS
  Group 1 (n = 46) consisted of 25 men and 21 women (age = 22.4 ± 1.89 years). Group 2 (n = 45) consisted of 17 men and 28 women (age = 20.9 ± 1.72 years).
  
  
  METHODS
  Both groups completed ImPACT forms 1, 2, and 3, which were delivered sequentially either at 1-week intervals (group 1) or at baseline, day 45, and day 50 (group 2). Group 2 also completed the Green Word Memory Test (WMT) as a measure of effort.
  
  
  METHODS
  Intraclass correlation coefficients (ICCs) were calculated for the composite scores of ImPACT between time points. Repeated-measures analysis of variance was used to evaluate changes in ImPACT and WMT results over time.
  
  
  RESULTS
  The ICC values for group 1 ranged from 0.26 to 0.88 for the 4 ImPACT composite scores. The ICC values for group 2 ranged from 0.37 to 0.76. In group 1, ImPACT classified 37.0% and 46.0% of healthy participants as impaired at time points 2 and 3, respectively. In group 2, ImPACT classified 22.2% and 28.9% of healthy participants as impaired at time points 2 and 3, respectively.
  
  
  CONCLUSIONS
  We found variable test-retest reliability for ImPACT metrics. Visual motor speed and reaction time demonstrated greater reliability than verbal and visual memory. Our current data support a multifaceted approach to concussion assessment using clinical examinations, symptom reports, cognitive testing, and balance assessment.
authors.affiliation: University of Texas at Arlington, Box 19259, 113 Maverick Activities Center, Arlington, TX 76102, USA. resch@uta.edu
authors.forename: Jacob
authors.initials: J
authors.lastname: Resch
authors.forename: Aoife
authors.initials: A
authors.lastname: Driscoll
authors.forename: Noel
authors.initials: N
authors.lastname: McCaffrey
authors.forename: Cathleen
authors.initials: C
authors.lastname: Brown
authors.forename: Michael S
authors.initials: MS
authors.lastname: Ferrara
authors.forename: Stephen
authors.initials: S
authors.lastname: Macciocchi
authors.forename: Ted
authors.initials: T
authors.lastname: Baumgartner
authors.forename: Kimberly
authors.initials: K
authors.lastname: Walpert
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001924:Brain Concussion / Q000175:diagnosis; D003072:Cognition Disorders / Q000175:diagnosis; D003430:Cross-Sectional Studies; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000592:standards*; D011594:Psychometrics; D015203:Reproducibility of Results; D055815:Young Adult