Análise das propriedades de medida da versão brasileira da Copenhagen Neck Functional Disability Scale (CNFDS)

Abstract

Objective: This study aims to evaluate the properties of the Brazilian version of Copenhagen Neck Functional Disability Scale (CNFDS) measurements in patients with chronic neck pain. Methods: In order to validate the measurements of this Brazilian version, an analysis was developed based on a sample of 105 patients and evaluated by exploratory and confirmatory factor analysis with the following fit indices: Chi-square (X²), Chi-square/degrees of freedom (X²/df), Root Mean Square Error of Approximation (RMSEA), Comparative Fit Index (CFI) and Tucker Lewis Index (TLI). The same number of volunteers was used to test the construct validity using Spearman's correlation (rho). The CNFDS was correlated with the following instruments used in this study: Numerical Pain Scale (NPS), Tampa Scale for Kinesiophobia (TSK), Catastrophizing Thoughts Scale (CTS) and Neck Disability Index (NDI). A subsample of 43 patients answered the CNFDS in two moments within minimum term of just above 7 days, in order to assess test-retest reliability, it was used the using intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimum detectable change (MDC). The analysis of the internal consistency of CNFDS was based on Cronbach's alpha (). The floor and ceiling effects were also evaluated in the study. Results: The factor analysis identified a unidimensional structure of the CNFDS with adequate fit indices: Chi-square/df = 1.37, CFI = 0.94, TLI = 0.93, RMSEA (95% CI) = 0.059 (0.029 to 0.084). CNFDS presented satisfactory reliability in the results (ICC = 0.93) and internal consistency ( = 0.84). The SEM was 1.72 and the MDC was 4.76. CNFDS showed a strong correlation with the NDI (rho = 0.718), and weak correlation with the other instruments: NPS at rest (rho = 0.221) and in movement (rho = 0.215), TSK (rho = 0.290), CTS (rho = 0.462). There were no floor or ceiling effects. Discussion: We observed that the CNFDS showed high reliability, adequate internal consistency, and strong correlation with the NDI, it has demonstrated to be an appropriate instrument for assessing the impact of chronic neck pain on disability conditions. In addition, the CNFDS is easy to be applied and to be understood, and to be quickly filled it out. Conclusion: The Brazilian version of the CNFDS with unidimensional structure and 15 items has adequate measurement property which supports its use in clinical context and in research with patients with chronic pain in the cervical segment