1. Department of Audiology and Phoniatrics; Charité University Medicine Berlin; Berlin Germany
2. Department of Otorhinolaryngology; Klinikum Stuttgart, Katharinenhospital; Stuttgart Germany
3. Department of Otorhinolaryngology; Medical University of Graz; Graz Austria
4. Department of Otorhinolaryngology; Otto-von-Guericke University Magdeburg; Magdeburg Germany
5. Department of Otorhinolaryngology; Head and Neck Surgery; University of Cologne; Cologne Germany
6. Department of Otorhinolaryngology; Head and Neck Surgery; University Hospital Giessen and Marburg; Giessen Germany
7. Department of Otorhinolaryngology; University of Wuerzburg; Wuerzburg Germany
8. Department of Otorhinolaryngology; SRH Wald-Klinikum Gera; Gera Germany
9. Department of Otorhinolaryngology; Jena University Hospital; Jena Germany