What Does That Mean? Terms to know when talking about Narcolepsy - Wake Up Narcolepsy. Multiple Sleep Latency Test (MSLT) - Conducted after the overnight portion of a sleep study (PSG), the MSLT is a series of naps to assess the quality of sleep at night and the degree of sleepiness during the day. 4-5 naps scheduled at 2 hour intervals beginning a couple hours after you wake up. Falling asleep quickly and entering REM sleep during naps is an indication of Narcolepsy. Documents how readily a person can fall asleep, REM patterns, eye movements, heart rate, chin movements and certain brain activities.