[1] Antwerp Univ Hosp, Dept Pulm Med, B-2650 Antwerp, Belgium
[2] Univ Med Mannheim, HNO Klin, D-68167 Mannheim, Germany
[3] Intersom Koln, Zentrum Schlafmed & Schlafforsch, D-50670 Cologne, Germany
[4] St Anna Klin Wuppertal, Klin Hals Nasen & Ohrenheilkunde, D-42109 Wuppertal, Germany
[5] Antwerp Univ Hosp, Dept ENT, B-2650 Antwerp, Belgium