A 48-year-old man is evaluated for excessive daytime sleepin…
A 48-year-old man is evaluated for excessive daytime sleepiness. His overnight polysomnography is normal. During multiple sleep latency testing (MSLT), he falls asleep within 4 minutes on average and enters REM sleep during two of the nap trials. He reports no history of cataplexy. CSF hypocretin levels are normal. Which diagnosis is most appropriate?