1. Department of Neurology; Beijing Tiantan Hospital, Capital Medical University; Beijing 100050 China
2. Department of Endocrinology; Beijing Tiantan Hospital, Capital Medical University; Beijing 100050 China
3. Department of Neurology; Peking Union Medical College Hospital, Chinese Academy of Medical Science; Beijing 100730 China
4. Division of Clinical Electrophysiology; Department of Neurology; College of Medicine, University of Iowa; Iowa City IA, USA