HCRT and narcolepsy: However, these findings are somewhat inconsistent with an earlier study that measured CSF orexin levels in five iRBD patients and control group (consisting of narcolepsy and multiple sclerosis patients) and reported slightly higher orexin levels between 250 and 454 pg/ml (mean 369.2 ± 43.91 pg/ml) in iRBD group [55].