1. Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Samsung Biomedical Research Institute (SBRI), Seoul, Korea.
3. Department of Neurology, Chungnam National University School of Medicine, Daejeon, Korea.
4. Department of Electrical & Computer Engineering, University of Houston, Houston, TX, USA.
5. Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Korea.
6. Department of Medical Physics, University of Science and Technology, Daejeon, Korea.