1 School of Medicine, University College Dublin, Dublin, Ireland walter.mcnicholas@ucd.ie.
2 Department of Respiratory and Sleep Medicine, St Vincent's Hospital Group, Dublin, Ireland.
3 The Reykjavik University Sleep Institute, Reykjavik University, Reykjavik, Iceland.
4 Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland.
5 Department of Technical Physics, University of Eastern Finland, Kuopio, Finland.
6 Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.
7 School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia.
8 Sleep Disorders Center, Dept of Respiratory Medicine, Medical School, University of Crete, Heraklion, Greece.
9 Bethanien Hospital, Clinic of Pneumology and Allergology, Center for Sleep Medicine and Respiratory Care, Institute of Pneumology at the University of Cologne, Solingen, Germany.