1. Department of Neurosurgery, NTT Medical Center Tokyo, Shinagawa-ku, Tokyo, Japan;
2. Graduate School of Public Health, Teikyo University Itabashi-ku, Tokyo, Japan;
3. Department of Rehabilitation, NTT Medical Center Tokyo, Shinagawa-ku, Tokyo, Japan;
4. Department of Neurosurgery, The University of Tokyo Hospital, Bunkyo-ku, Tokyo, Japan