[1] Kanazawa Univ, Sch Med, Dept Neurol, Kanazawa, Ishikawa 9208640, Japan
[2] Tokyo Metropolitan Bokutoh Gen Hosp, Dept Infect Dis, Tokyo, Japan
[3] Tokyo Med & Dent Univ, Dept Internal Med, Tokyo 113, Japan
[4] Tokyo Med & Dent Univ, Dept Neuropathol, Med Res Inst, Tokyo 113, Japan