1. Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
2. Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
3. Department of Public Health, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
4. Biostatistics Consulting Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan