1. Graduate School of Gerontology, J. F. Oberlin University, Machida-shi 194-0294, Japan
2. Hachioji Azumacho Clinic, Hachioji-shi 192-0082, Japan
3. Sapporo Kita Clinic, Sapporo-shi 001-0018, Japan
4. Kawakita General Hospital, Suginami-ku 166-0001, Japan
5. School of Nursing, Jikei University, Chofu-shi 182-08570, Japan
6. Faculty of Health Care and Nursing, Juntendo University, Urayasu-shi 279-0023, Japan