Despite having more treatment options than ever before, narcolepsy remains significantly underdiagnosed. Is there a potential clue on the polysomnogram (PSG) that we are overlooking? Dr. Alyssa Cairns and her team are exploring the biophysiological phenotypes of sleep disorders, specifically central disorders of hypersomnolence. She discussed how she combed through half-a-million sleep records and looked at the predictive value of a sleep-onset REM period (SOREMP) on PSG for a future diagnosis of narcolepsy.