1. Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Republic of Korea
2. Department of Mechanical and Aerospace Engineering, University of California at Irvine, Irvine, CA, USA
3. Department of Human Systems Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
4. Department of Biomedical Engineering, University of California at Irvine, Irvine, CA, USA
5. Department of Anatomy and Neurobiology, University of California at Irvine, Irvine, CA, USA
6. Department of Physical Medicine and Rehabilitation, University of California at Irvine, Irvine, CA, USA