1. Department of Neurosurgery, Kansai Medical University, Hirakata, Osaka;
2. Department of Neurosurgery, Jikei Medical University, Minato-Ku, Tokyo;
3. Department of Neurology, Hokkaido University, Sapporo, Hokkaido;
4. Department of Public Health, Dokkyo Medical University, Mibu, Tochigi; and
5. National Hospital Organization, Matsue Medical Center, Matsue, Shimane, Japan