[1] Univ Hosp Leuven, Dept Otorhinolaryngol Head & Neck Surg, Leuven, Belgium
[2] Univ Ghent, Dept Otorhinolaryngol, Lab Upper Airways Res, Ghent, Belgium
[3] Acad Med Ctr Amsterdam, Dept Otorhinolaryngol, Amsterdam, Netherlands
[4] Jessa Hosp, Dept Otorhinolaryngol Head & Neck Surg, Hasselt, Belgium
[5] Guys & St Thomas Hosp, Dept Otorhinolaryngol, London, England
[6] Clin Univ St Luc, Dept Otorhinolaryngol Head & Neck Surg, Brussels, Belgium
[7] Univ Hosp Leuven, Dept Infect Control & Epidemiol, Leuven, Belgium
[8] Katholieke Univ Leuven, Dept Publ Hlth & Primary Care, Leuven, Belgium
[9] Univ Hosp Leuven, Dept Gastroenterol & Hepatol, Leuven, Belgium
[10] Sint Jan Hosp, Dept Otorhinolaryngol Head & Neck Surg, Brugge, Belgium
[11] Univ Hosp Leuven, Dept Oncol, Sect Head & Neck Oncol, Leuven, Belgium
[12] Univ Hosp Antwerp, Dept Otorhinolaryngol Head & Neck Surg, Antwerp, Belgium
[13] Hosp Clin Barcelona, Rhinol Unit, Barcelona, Spain
[14] Ctr Med TEKNON, ENT Dept, Smell Clin, Barcelona, Spain