title: Generalizability theory analysis of balance error scoring system reliability in healthy young adults.
abstract: BACKGROUND
  An assessment of postural control is commonly included in the clinical concussion evaluation. Previous investigators have demonstrated learning effects that may mask concussion-induced balance decrements.
  
  
  OBJECTIVE
  To establish the test-retest reliability of the Balance Error Scoring System (BESS) and to provide recommendations that account for known learning effects.
  
  
  METHODS
  Test-retest generalizability study.
  
  
  METHODS
  Balance research laboratory.
  
  
  METHODS
  Young adults (n = 48) free from injuries and illnesses known to affect balance.
  
  
  METHODS
  Each participant completed 5 BESS trials on each of the assessment dates, which were separated by 50 days.
  
  
  METHODS
  Total score of the BESS was used in a generalizability theory analysis to estimate the overall reliability of the BESS and that of each facet. A decision study was completed to estimate the number of days and trials needed to establish clinical reliability.
  
  
  RESULTS
  The overall reliability of the BESS was G = 0.64. The test-retest reliability was improved when male (0.92) and female (0.91) participants were examined independently. Clinically acceptable reliability (greater than 0.80) was established when 3 BESS trials were administered in a single day or 2 trials were administered at different time points.
  
  
  CONCLUSIONS
  Learning effects have been noted in individuals with no previous exposure to the BESS. Our findings indicate that clinicians should consider interpreting the mean score from 3 BESS administrations on a given occasion for both normative data comparison and pretest and posttest design. The multiple assessment technique yields clinically reliable scores and provides the sports medicine practitioner with accurate data for clinical decision making.
authors.affiliation: University of Illinois at Urbana-Champaign, Urbana, IL, USA. broglio@illinois.edu
authors.forename: Steven P
authors.initials: SP
authors.lastname: Broglio
authors.forename: Weimo
authors.initials: W
authors.lastname: Zhu
authors.forename: Kay
authors.initials: K
authors.lastname: Sopiarz
authors.forename: Youngsik
authors.initials: Y
authors.lastname: Park
mesh_terms: D001924:Brain Concussion / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index