1. University Medical Center Utrecht; Julius Center for Health Sciences and Primary Care & Department of Otorhinolaryngology; Heidelberglaan 100 Utrecht Netherlands 3508 GA
2. UK Cochrane Centre; Summertown Pavilion 18 - 24 Middle Way Oxford UK OX2 7LG
3. University Medical Center Utrecht; Department of Otorhinolaryngology & Julius Center for Health Sciences and Primary Care; Utrecht Netherlands
4. Academic Center for Dentistry Amsterdam (ACTA); Department of Social Dentistry; 5th Floor, Room 5N03 Gustav Mahlerlaan 3004 Amsterdam Netherlands 1081LA
5. Faculty of Brain Sciences, University College London; evidENT, Ear Institute; 330 Grays Inn Road London UK WC1X 8DA