[1] Univ Gothenburg, Sahlgrenska Acad, Inst Neurosci & Physiol, Dept Clin Neurosci, Gothenburg, Sweden
[2] Sahlgrens Univ Hosp, Dept Neurosurg, Bla Straket 5, S-41345 Gothenburg, Sweden
[3] Sahlgrens Univ Hosp, Dept Med, Gothenburg, Sweden
[4] Univ Gothenburg, Sahlgrenska Acad, Inst Med, Dept Internal Med & Clin Nutr, Gothenburg, Sweden
[5] Univ Gothenburg, Sahlgrenska Acad, Inst Hlth & Care Sci, Gothenburg, Sweden
[6] Sahlgrens Univ Hosp, Dept ENT H&N Surg, Gothenburg, Sweden
[7] Univ Gothenburg, Sahlgrenska Acad, Inst Clin Sci, Dept Otorhinolaryngol, Gothenburg, Sweden