1. Department of Otolaryngology, Sahlgrenska Sjukhuset, Göteborg, Sweden
2. Department of Audiology, Sahlgrenska Sjukhuset, Göteborg, Sweden
3. Department of Neurology, Sahlgrenska Sjukhuset, Göteborg, Sweden
4. Department of Virology, Sahlgrenska Sjukhuset, Göteborg, Sweden
5. Department of Psychiatry and Neurochemistry, St Jörgen's Hospital, University of Göteborg, Göteborg, Sweden