[1] Mayo Clin, Dept Otolaryngol Head & Neck Surg, Sch Med, Rochester, MN 55905 USA
[2] Bergen Univ Hosp, Dept Neurosurg, Bergen, Norway
[3] Mayo Clin, Sch Med, Dept Neurol Surg, Rochester, MN 55905 USA
[4] Mayo Clin, Sch Med, Dept Neurol, Rochester, MN 55905 USA
[5] Mayo Clin, Sch Med, Dept Psychiat & Psychol, Rochester, MN 55905 USA
[6] Bergen Univ Hosp, Dept Otolaryngol, Bergen, Norway
[7] Univ Bergen, Inst Surg Sci, Bergen, Norway