1. Graduate School of Engineering, Kagawa University, Takamatsu, Japan
2. Key Laboratory of Convergence Medical Engineering System and Healthcare Technology, the Ministry of Industry and Information Technology, Beijing Institute of Technology, Beijing, China
3. National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Japan
4. Department of Neurological Surgery, Faculty of Medicine, Kagawa University, Takamatsu, Japan
5. Faculty of Engineering and Design, Kagawa University, Takamatsu, Japan