1. Graduate School, Qinghai University, Xining, Qinghai 810016, China
2. Department of Neurosurgery, Qinghai Provincial People's Hospital, Xining, Qinghai 810007, China
3. Department of Community Health Education, Institute for Health Education of Qinghai Province, Xining, Qinghai 810000, China
4. Department of Neurological Intensive Care, Shengli Oilfield Central Hospital, Dongying, Shandong 257000, China
5. Medical College of Qinghai University, Xining, Qinghai 810016, China