[1] Niigata Univ, Brain Res Inst, Dept Neurol, Niigata 9518585, Japan
[2] Kanazawa Univ, Sch Med, Dept Neurol, Kanazawa, Ishikawa 920, Japan
[3] Kumamoto Univ, Sch Med, Dept Neurol, Kumamoto 860, Japan
[4] Tokyo Med & Dent Univ, Dept Neurol, Tokyo 113, Japan
[5] Natl Saigata Hosp, Dept Neurol, Niigata, Japan