Cross-cultural adaptation of the Nordic musculoskeletal questionnaire.

BACKGROUND: Reports in the literature have identified a need for internationally standardized and reliable measurements to analyse musculoskeletal symptoms. Screening of musculoskeletal disorders may serve as a diagnostic tool to evaluate the work environment. The Nordic general questionnaire is a standardized instrument used to analyse musculoskeletal symptoms in an ergonomic or occupational health context.
PURPOSE: To translate and adapt a version of the Nordic general questionnaire into Brazilian Portuguese and evaluate its reliability.
METHOD: The cross-cultural adaptation was performed according to internationally recommended methodology, using the following guidelines: translation; back-translation; committee review; and pretesting. First, the questionnaire was independently translated into Portuguese by two teachers and one doctor, and a consensus version was generated. Second, two other translators performed a back-translation independently from one another. This version was then submitted to a committee, consisting of six specialists in the area of knowledge of the instrument, to evaluate its equivalence to the original instrument. The final version was pretested on 20 subjects randomly selected in an outpatient clinic. Reliability was assessed by a test-retest procedure at 1-day intervals using the Kappa coefficient in a group of 40 subjects. The Kappa agreement values were calculated for each one of the four questions of the questionnaire. The agreement among the same observers was substantial, varying from 0.88 to 1, according to the Kappa values.
RESULTS: these demonstrated strong agreement of the instrument, suggesting that the Brazilian version of the "Standardized Nordic Questionnaire" offers substantial reliability.