Fig. 2

Orexin levels in narcolepsy type1 (NT1), NPC and idiopathic hypersomnia (IHS). The CSF orexin levels of NPC patients were significantly higher than those of patients with narcolepsy type 1 (p < 0.01) and lower than those of patients with idiopathic hypersomnia (p < 0.01), considered as the control group with normal CSF orexin levels