BRAZILIAN VERSION OF VESTIBULAR ACTIVITIES AND PARTICIPATION MEASURE: CROSS-CULTURAL ADAPTATION, VALIDITY, INTERNAL CONSISTENCY, RELIABILITY AND MEASUREMENT ERROR
vestibular disorders, dizziness, postural balance, data accuracy, validation studies, psychometrics.
Background: Vestibular Activities and Participation measure (VAP) is an instrument that measures the effect of vestibular disorders on activity and participation using items from the International Classification of Functioning, Disability and Health. Two independent subscales were developed from 34-item original version. Objective: to perform cross-cultural adaptation of the VAP subscales and to evaluate their measurement properties (validity, internal consistency, reliability and measurement error). Methods: this is a methodological study, in which the cross-cultural adaptation followed the steps of translation, synthesis, back-translation, review by a committee of experts and pre-test. Structural validity was assessed using exploratory (EFA) and confirmatory (CFA) factor analysis, while hypothesis testing was analyzed by correlating the VAP subscales with Dizziness Handicap Inventory (DHI). Cronbach's alpha was used to measure internal consistency. Intraclass Correlation Coefficient (ICC) was used for assessing intra- and interrater reliability and measurement error was calculated by Standard Error of Measurement (SEM) and Smallest Detectable Change (SDC). Results: VAP-BR subscales received some additional information in order to improve the understanding of the volunteers in pre-test. One factor was found in EFA for each subscale with 50% explained variance. In CFA, subscales 1 and 2 presented, respectively, adequate model fit indices (X2/df: 1.08 and 1; CFI: 0.99 for both; GFI: 0.97 and 0.98; RMESA: 0.03 and 0.08; SRMR: 0.04 and 0.01). Chronbach's alpha values found were 0.80 for subscale 1 and 0.82 for subscale 2. Subscales 1 and 2 presented respective ICC = 0.87 and 0.90; SEM = 1.01 and 1.16; and SDC = 2.79 and 3.22 for intra-rater assessment. When assessed by two different raters, both subscales showed ICC = 0.92, while values to SEM = 1.03 and 1.53; and SDC = 2.85 and 4.23 were found in subscales 1 and 2, respectively. Correlations between DHI and VAP subscales revealed coefficients above 0.57. Conclusion: Brazilian version of Vestibular Activities and Participation subscales have adequate measurement properties. Thus, VAP-BR subscales become relevant for Brazilian population with vestibular disorders in order to identify their activity limitations and participation restrictions.