1. Department of Neurology, Korea University College of Medicine, Seoul, South Korea
2. Department of Neurology, Sleep Center, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea
3. Department of Psychiatry, Korea University College of Medicine, Seoul, South Korea
4. Department of Preventive Medicine, College of Medicine and Institute for Environmental Health, Medical Science Research Center, Korea University, Seoul, South Korea
5. Department of Neurology, Seoul National University College of Medicine, Seoul, South Korea