1 Division of Neurology, Department of Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina.
2 Section on Sleep Medicine, Department of Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina.
3 Division of Pulmonary, Critical Care Medicine, Allergy and Immunology, Department of Medicine, Wake Forest School of Medicine, Winston Salem, North Carolina; W. G. (Bill) Hefner Veterans Affairs Medical Center, Salisbury, North Carolina. Electronic address: gkrishna@wakehealth.edu.