[1] Natl Univ Singapore, Yong Loo Lin Sch Med, Singapore 117595, Singapore
[2] Natl Neurosci Inst, Dept Neurol, Off Neurol Educ, Singapore, Singapore
[3] Natl Univ Hlth Syst, Dept Med, Singapore, Singapore
[4] Tan Tock Seng Hosp, Dept Gen Med, Singapore, Singapore