- Have valid PSG & MSLT scores (collected during an overnight test) within last five years and a current diagnosis of narcolepsy according to the following criteria established by the American Sleep Disorders Association: (1) Recurrent daytime naps or lapses into sleep occur almost daily for at least 3 months; (2) Sudden bilateral loss of postural muscle tone occurs in association with intense emotion (cataplexy); (3) Polysomnography demonstrates one or more of the following: (a) Sleep latency less than 10 minutes; (b) REM sleep latency less than 20 minutes; (c) An MSLT that demonstrates a mean sleep latency of less than 5 minutes; (d) Two or more sleep-onset REM periods