1. Department of Rehabilitation Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
2. Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Gyeonggi-Do, Korea.
3. Department of Rehabilitation Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea.
4. Department of Physical and Rehabilitation Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.