Abstract
BACKGROUND: Two validated German-language versions of the Tinnitus Functional Index (TFI) exist, one for Switzerland and one for Germany. The TFI is considered to be a possible new standard questionnaire for evaluation of tinnitus severity and tinnitus treatment. OBJECTIVE: Considering the standardization taking place in tinnitus evaluation, our aim was to compare the two German-language TFI versions and to recommend only one TFI version in the German-speaking area. MATERIALS AND METHODS: The two German-language TFI versions were compared in a multicenter and randomized online questionnaire study with a crossover design. RESULTS: The total score of the two TFI versions did not differ in the total population. However, when further divided in terms of population and order of presentation of the TFI versions, there were significant differences in some cases, albeit with only moderate effect sizes. This suggests that the two versions are slightly different but still comparable. In factor analysis for the TFI version for Germany, in the entire population as well as in the Swiss population, six factors could be extracted. In contrast, for the German and Swiss TFI versions, only five factors could be extracted in the German population, and for the Swiss TFI version, only five factors in the Swiss population. CONCLUSION: The two German-language versions of the TFI are well comparable with each other. However, the factor analysis rather argues for use of the TFI version for Germany in the entire German-speaking region.