title: The Cumberland ankle instability tool: a report of validity and reliability testing.
abstract: OBJECTIVE
  To test the Cumberland Ankle Instability Tool (CAIT), a 9-item 30-point scale, for measuring severity of functional ankle instability.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  General community.
  
  
  METHODS
  Volunteer sample of 236 subjects.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Concurrent validity by comparison with the Lower Extremity Functional Scale (LEFS) and a visual analog scale (VAS) of global perception of ankle instability by using the Spearman rho. Construct validity and internal reliability with Rasch analysis using goodness-of-fit statistics for items and subjects, separation of subjects, correlation of items to the total scale, and a Cronbach alpha equivalent. Discrimination score for functional ankle instability by maximizing the Youden index and tested for sensitivity and specificity. Test-retest reliability by intraclass correlation coefficient, model 2,1 (ICC(2,1)).
  
  
  RESULTS
  There were significant correlations between the CAIT and LEFS (rho=.50, P<.01) and VAS (rho=.76, P<.01). Construct validity and internal reliability were acceptable (alpha=.83; point measure correlation for all items, >0.5; item reliability index, .99). The threshold CAIT score was 27.5 (Youden index, 68.1); sensitivity was 82.9% and specificity was 74.7%. Test-retest reliability was excellent (ICC(2,1)=.96).
  
  
  CONCLUSIONS
  CAIT is a simple, valid, and reliable tool to measure severity of functional ankle instability.
authors.affiliation: School of Physiotherapy, University of Sydney, Lidcombe, Australia.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Hiller
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Refshauge
authors.forename: Anita C
authors.initials: AC
authors.lastname: Bundy
authors.forename: Rob D
authors.initials: RD
authors.lastname: Herbert
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Kilbreath
mesh_terms: D000328:Adult; D016512:Ankle Injuries / Q000145:classification*; D003430:Cross-Sectional Studies; D006801:Humans; D015601:Injury Severity Score; D007593:Joint Instability / Q000145:classification*; D012372:ROC Curve; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires