12 Hiller - The Cumberland Ankle Instability Tool (CAIT) was

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12 Hiller - The Cumberland Ankle Instability Tool (CAIT) was Powered By Docstoc
 Hiller CE, Refshauge KR, Bundy A, Herbert RD, Kilbreath SL. School of
 Physiotherapy, Faculty of Health Sciences, University of Sydney, NSW,

Background: There is no reliable and valid assessment tool for objectively
defining functional ankle instability (FAI). Purpose: To develop and test the
properties of the Cumberland Ankle Instability Tool (CAIT), designed to
measure FAI. CAIT is self-administered, with 9 questions relating to subjects’
perception of ankle stability during various activities. Methods: To assess
convergent validity, the CAIT (30 point scale) was compared with the Lower
Extremity Functional Scale (LEFS) and a Visual Analogue Scale (VAS) for
perception of ankle instability in 92 subjects (age 23 ± 6.1 years): 35 with no
prior ankle sprain, 27 with a history of unilateral sprain, and 30 with a history
of bilateral sprains. Rasch analysis was undertaken to determine if CAIT could
distinguish between subjects with and without FAI, and could discriminate
degrees of FAI severity, in 153 subjects (age 23.2 ± 6.8 years): 56 subjects
with no prior sprain, 45 with a history of unilateral sprain, and 50 with a
history of bilateral sprains. A cut-off point for identification of FAI was
determined by the score, which produced the maximum Youden’s index using
data from half the sample. Sensitivity and specificity were determined using
data from the other half of the sample. Reliability was tested by administering
CAIT to 18 subjects (age 41.3 ± 9.4 years) on 2 occasions at least 2 weeks
apart. Results: There was a moderate correlation between the LEFS and the
CAIT (r = 0.52, p < 0.01) and a strong correlation between the CAIT and the
VAS (r = 0.84, p < 0.01) indicating that the CAIT correlated well with
subjects’ overall perception of ankle instability. Rasch analysis demonstrated
that CAIT identified two groups (subjects with FAI and controls) and
measured a range of severity of functional ankle instability (18.9 range in a
30-point scale) with high reliability (Crohnbach’s α = 0.82). The maximum
Youden’s index was 68.1, obtained at a cut-off CAIT score of 27.5. This cut-
off had a sensitivity of 82.9% and specificity of 74.7%. There was high test-
retest reliability (ICC(2,1) = 0.96, 95% CI 0.93-0.98). There was exact
agreement between the two test occasions in 12 responses (33.3%), and 30
responses (83.3%) were within 2 points. The Bland-Altman plot demonstrated
that CAIT was equally reliable across the range of scores. Conclusions: The
CAIT is a valid and reliable tool for determining and measuring functional
ankle instability. Keywords: Functional ankle instability, questionnaire,

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