1. Department of Otorhinolaryngology, Head and Neck Surgery, and Audiology, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
2. Frederiksberg Øre-næse-halsklinik (Frederiksberg Ear, Nose, and Throat Clinic), Frederiksberg, Denmark
3. Department of Clinical Neurophysiology, Copenhagen University Hospital (Rigshospitalet), Glostrup, Denmark
4. Øre-næse-halsklinikken i Hørsholm (Hoersholm Ear, Nose, and Throat Clinic), Hoersholm, Denmark
5. Øre næse hals klinikken ved Steffen Ørntoft (Ear, Nose, and Throat Clinic by Steffen Oerntoft), Hvidovre, Denmark