Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, P.R. China. The Key Laboratory of Neurology (Hebei Medical University), Ministry of Education, Shijiazhuang, Hebei, P.R. China. Neurological Laboratory of Hebei Province, Shijiazhuang, Hebei, P.R. China, and. Department of Neurology, Xingtai Third Hospital, Xingtai, P.R. China.