Validation and investigation of cross cultural equivalence of the Fremantle back awareness questionnaire - German version (FreBAQ-G)

Background: Disrupted self-perception of the low back might contribute to chronic non-specific low back pain. The Fremantle back awareness questionnaire is a simple questionnaire to assess back specific self-perception. The questionnaire has recently been translated to German (FreBAQ-G). The aim was to further investigate the psychometric properties of the FreBAQ-G, to evaluate its cross cultural validity in patients with chronic non-specific LBP and to explore potential relationships between body perception, pain, disability and back pain beliefs. Methods: In this cross-sectional multicentre study, sample data were merged with data from the validation sample of the original English version to examine cross-cultural validity. Item Response Theory was used to explore psychometric properties and differential item function (DIF) to evaluate cross-cultural validity and item invariance. Correlations and multiple linear regression analyses were used to explore the relationship between altered back specific self- perception and back pain parameters. Results: Two hundred seventy-two people with chronic low back pain completed the questionnaires. The FreBAQ-G showed good internal consistency (Cronbach’s alpha = 0.84), good overall reliability (r = 0.84) and weak to moderate scalability (Loevinger Hj between 0.34 and 0.48). The questionnaire showed unidimensional properties with factor loadings between 0.57 and 0.80 and at least moderate correlations (r > 0.35) with pain intensity, pain related disability and fear avoidance beliefs (FABQ total - and subscores). Item and test properties of the FreBAQ-G are given. Only item 7 showed uniform DIF indicating acceptable cross-cultural validity. Conclusions: Our results indicate that the FreBAQ-G is a suitable questionnaire to measure back specific self-perception, and has comparable properties to the English-language version.