1. Hospital Alvarez Buylla; ENT Department; Murias s/n Mieres Asturias Spain
2. The Elms Medical Practice; Tilley Close Hoo Rochester Kent UK ME3 9AE
3. University of Cambridge; Department of Public Health and Primary Care; Forvie Site, Robinson Way Cambridge Biomedical Campus Cambridge Cambridgeshire UK CB2 0SR
4. Faculty of Brain Sciences, University College London; Ear Institute; London UK
5. Harvard Medical School and Boston Children's Hospital; Department of Otolaryngology; Boston USA
6. Tampere University Hospital; Department of Otorhinolaryngology; Tampere Finland
7. Ludwig-Maximilians-University Hospital Munich; Department of Neurology and German Center for Vertigo and Balance Disorders; Campus Großhadern Marchioninistr. 15 Munich Germany 81377