Validation of the Brazilian-Portuguese version of the Gesture Behavior Test for patients with non-specific chronic low back pain

ABSTRACT

OBJECTIVE: To developa Brazilian version of the gesture behavior test (GBT) for patients with chronic low back pain. METHODS: Translation of GBT into Portuguese was performed by a rheumatologist fluent in the language of origin (French) and skilled in the validation of questionnaires. This translated version was back-translated into French by a native-speaking teacher of the language. The two translators then created a final consensual version in Portuguese. Cultural adaptation was carried out by two rheumatologists, one educated patient and the native-speaking French teacher. Thirty patients with chronic low back pain and fifteen healthcare professionals involved in the education of patients with low back pain through back schools (gold-standard) were evaluated. Reproducibility was initially tested by two observers (inter-observer); the procedures were also videotaped for later evaluation by one of the observers (intra-observer). For construct validation, we compared patients' scores against the scores of the healthcare professionals. RESULTS: Modifications were made to the GBT for cultural reasons. The Spearman's correlation coefficient and the intra-class coefficient, which was employed to measure reproducibility, ranged between 0.87 and 0.99 and 0.94 to 0.99, respectively (p < 0.01). With regard to validation, the Mann-Whitney test revealed a significant difference (p < 0.01) between the averages for healthcare professionals (26.60; SD 2.79) and patients (16.30; SD 6.39). There was a positive correlation between the GBT score and the score on the Roland Morris Disability Questionnaire (r= 0.47). CONCLUSIONS: The Brazilian version of the GBT proved to be a reproducible and valid instrument. In addition, according to the questionnaire results, more disabled patients exhibited more protective gesture behavior related to low-back.