CSF orexin levels of Parkinson's disease, dementia with Lewy bodies, progressive supranuclear palsy and corticobasal degeneration.

Excessive daytime sleepiness has been widely accepted as a common problem not only in Parkinson's disease (PD) but also in other related disorders. Lowered excretion of orexin A (hypocretin 1) into the cerebrospinal fluid (CSF) is known to play a pathological role in narcolepsy and secondary hypersomnia due to hypothalamic dysfunction. Although the levels of CSF orexin in PD have been previously examined, the results have been controversial, and no systematic investigation of CSF orexin excretion has been conducted on PD related disorders. In this study, orexin was measured in CSF collected by lumbar puncture in 62 patients with PD, 13 patients with dementia with Lewy bodies (DLB), 16 patients with progressive supranuclear palsy (PSP), and 7 patients with corticobasal degeneration (CBD). Levels of CSF orexin (mean+/-SD pg/ml) were 302+/-38 in PD, 297+/-48 in DLB, 258+/-37 in PSP, 246+/-90 in CBD. The occurrence of low orexin levels (