1. Department of Anaesthesiology, Intensive Care and Pain Medicine, Tan Tock Seng Hospital, Singapore
2. Department of Neurosurgery, National Neuroscience Institute, Tan Tock Seng Hospital, Singapore
3. Department of Neurology, XuanWu Hospital Capital Medical University, Beijing, China
4. Department of Neurology, National Neuroscience Institute, Tan Tock Seng Hospital, Singapore