1 Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashimachi, Kodaira, Tokyo, 187-8551, Japan.
2 Department of Orthopedics, National Center of Neurology and Psychiatry, National Center Hospital, Kodaira, Japan.
3 Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
4 Department of Neurology, National Center Hospital, National Center of Neurology and Psychiatry, 4-1-1 Ogawahigashimachi, Kodaira, Tokyo, 187-8551, Japan. yutakahashi@ncnp.go.jp.