These occur in spite of "adequate, or more typically, extraordinary sleep amounts (e.g., greater than 10 hours per night)."[8] Sleep is usually deep, with significant difficulty arousing from sleep, even with use of several alarm clocks. In fact, patients with IH often must develop elaborate rituals to wake, as alarm clocks and even physical attempts by friends/family to wake them may fail. Despite getting more hours of sleep than typically required by the human body, patients awake unrefreshed and may also suffer sleep inertia, known more descriptively in its severe form as sleep drunkenness (significant disorientation upon awakening).[15] Daytime naps are generally very long (up to several hours) and are also unrefreshing, as opposed to the short refreshing naps associated with narcolepsy.[8] Sleep paralysis and hypnagogic hallucinations may also be seen, and these symptoms are as common in idiopathic hypersomnia as they are in narcolepsy without cataplexy.[10]