1. Department of Neurosurgery, Kyoto University, Kyoto, Kyoto, Japan
2. Department of Neurosurgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
3. Department of Cardiology, Gifu Heart Center, Gifu, Gifu, Japan
4. Department of Neurology, Kumamoto Red Cross Hospital, Kumamoto, Kumamoto, Japan