1. Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Physical Medicine and Rehabilitation, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
3. Department of Research and Analysis Team, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
4. National Traffic Injury Rehabilitation Hospital, Yangpyeong, Korea.
5. Institute on Aging, Seoul National University, Seoul, Korea.