1 Joan C Edwards School of Medicine, Vice-President for Health Affairs, Marshall University, Huntington, WV, USA.
2 Zentrum Fur Experimentelle Neurologie, Department of Neurology, Inselspital University Hospital Bern, Department of Biomedical Research, University of Bern, Bern, Switzerland.
3 California Pacific Medical Center Research Institute, Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
4 Division of Sleep Medicine/Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.