1 Center for Sleep Medicine, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA.
2 Department of Neurology, Mayo Clinic, Rochester, MN USA.
3 Department of Family Medicine, Mayo Clinic, Rochester, MN USA.
4 Division of Pulmonary Medicine, Mayo Clinic Hospital, Phoenix, AZ USA.
5 Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN USA.