1. Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Utrecht, the Netherlands
2. Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
3. Central Military Hospital, Utrecht, The Netherlands
4. Department of Otorhinolaryngology and Head and Neck Surgery, Rivierenland Hospital, Tiel, The Netherlands
5. Brain Center Rudolf Magnus, Utrecht, The Netherlands