1. Department of Otorhinolaryngology, Head and Neck Surgery, Eberhard Karls University, Tübingen, Tübingen, Germany;
2. Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital of Marburg, Philipps-Universität Marburg, Marburg, Germany;
3. Department of Otorhinolaryngology, Head and Neck Surgery “Otto Koerner”, Rostock University Medical Center, Rostock, Germany;
4. Department of Otolaryngology, Section of Physiological Acoustics and Communication, University of Tübingen, Tübingen, Germany;
5. Department of Otorhinolaryngology, Head and Neck Surgery, Ruhr University Bochum, St. Elisabeth-Hospital, Bochum