1. Division of Internal Medicine; Basel University Hospital; Basel Switzerland
2. Department of Neurology; Essen University Hospital; Essen Germany
3. Department of Neurology and German Center for Vertigo and Balance Disorders; University Hospital; Munich Germany
4. Institute of Medical Technology, Brandenburg University of Technology; Cottbus-Senftenberg; Senftenberg Germany
5. Serviço de Neurologia, Hospital Universitário Antonio Pedro; Universidade Federal Fluminense; Niteroi Rio de Janeiro Brazil
6. Ear, Nose and Throat Department of the 3rd Medical Faculty; Charles University; Prague Czech Republic
7. Department of Medicine; Giessen University Hospital; Giessen Germany
8. Department of Neurology; Bern University Hospital; Bern Switzerland