1. International Institute for Integrative Sleep Medicine (WPI‐IIIS) University of Tsukuba Tsukuba Japan
2. School of Medicine University of Tsukuba Tsukuba Japan
3. Department of Anaesthesiology Katsuta Hospital Hitachinaka Japan
4. Japan Life Science Centre for Tsukuba Advanced Research Alliance (TARA) University of Tsukuba Tsukuba Japan
5. Ibaraki Prefectural Medical Centre of Psychiatry Kasama Japan