1 Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Shaanxi, People's Republic of China, Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Shaanxi, People's Republic of China, Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, Shaanxi, People's Republic of China.
2 Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Shaanxi, People's Republic of China, Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Shaanxi, People's Republic of China.
3 Department of Geriatric Neurology, Shaanxi Provincial People's Hospital, Shaanxi, People's Republic of China, Shaanxi Provincial Clinical Research Center for Geriatric Medicine, Shaanxi, People's Republic of China, Xi'an Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Medical Research, Northwestern Polytechnical University, Shaanxi, People's Republic of China, rli@nwpu.edu.cn.