[Vocal fatigue as an indicator of complex voice disorders-a diagnostic and therapeutic challenge]. / Vocal Fatigue als Indikator für komplexe Stimmstörungen ­ eine diagnostische und therapeutische Herausforderung.

Vocal fatigue is increasingly observed among professional voice users (e.g., teachers). This pathologic state is associated with restrictions in everyday life and is considered to be an indicator of complex voice disorders. Since there are few systematic studies on the phenomenon, there is currently no uniform definition or diagnostic workup. Based on the case study of a professional speaker, possibilities for a structured vocal fatigue assessment are presented. These are discussed with regard to their laryngoscopic, instrumental acoustic ("performance fatigue") and subjective symptom-related characteristics ("perceived fatigue"). In addition, a differentiation from the vocal effort, vocal demand, and vocal demand response models according to Hunter et al. (2020) is made.

[Pretesting of the German Vocal Fatigue Index (VFI-D)-transcultural translation and cross validation]. / Prätestung des deutschen Vocal Fatigue Index (VFI-D) ­ transkulturelle Übersetzung und Kreuzvalidierung.

BACKGROUND: In clinical routine, vocal fatigue is a common symptom in patients with dysphonia. OBJECTIVE: The aim of this study was to conduct a transcultural translation of the Vocal Fatigue Index (VFI), a standardized subjective questionnaire. Furthermore, pretesting and prevalidation were performed in 20 subjects, with comparison to the Voice Handicap Index (VHI­9i) and the Vocal Tract Discomfort Scale (VTD). MATERIALS AND METHODS: The translation, content review, and pretest of the German Vocal Fatigue Index (VFI-D) was divided into four sections: 1. transcultural translation, 2. expert voting on comprehensibility, 3. test of comprehensibility through cognitive interviews in 15 participants, 4. pretest of the VFI­D with cross validation compared to VHI­9i and VTD in 20 subjects. This process corresponds to current standards for transcultural translation and adaptation of questionnaires. RESULTS: According to expert voting and cognitive testing, the VFI­D is correct and comprehensible (intercoder reliability κ = 0.66). The factor analysis revealed three distinguishable parts: VFI­D part 1 correlates strongly with VHI­9i and VTD, VFI­D part 2 with VTD only (rho ≈ 0.800 each), and VFI­D part 3 correlates only weakly with VHI­9i and VTD (rho ≈ 0.585). Thus, convergence and divergence validity are proven. CONCLUSION: The first German version of the VFI­D might be a base for further research on symptoms, causes, and treatment options in vocal fatigue. Particularly patients in voice-intensive professions may benefit.