Her first symptoms presented at age 9, but it would take two decades—and countless physician visits—until Julea Steiner received a correct diagnosis of narcolepsy. Steiner, MPH, CHES, now clinical assistant professor and director of professional development at UNC Gillings School of Global Public Health, had been seen by clinicians who misdiagnosed her with disorders ranging from ADHD to vitamin deficiency, or had even dismissed her symptoms out of hand.
Steiner’s long journey to diagnosis is fairly typical. As myths abound about narcolepsy’s symptoms, it is understandable that clinicians do not consistently recognize the sleep disorder as it presents in real life. In a Sleep Review webinar, Steiner recalled her Internet research in the intervening years. “I did have some sense that I had a sleep problem…but I never even clicked on the narcolepsy links, because I felt so sure I didn’t have it,” she said.
Temitayo O. Oyegbile, MD, PhD, a physician at MedStar Georgetown who is board certified in neurology and sleep medicine, noted that narcolepsy onset can be linked to weight gain. But sleep specialists might link the high body mass index to obstructive sleep apnea (OSA) and test for that disorder instead, especially since narcolepsy is rare.
And when the results of overnight polysomnography (PSG) for a patient assumed to have OSA show no sleep-disordered breathing, some conclude that no sleep disorder is present. Many clinicians are not aware that narcolepsy can leave clues in a nocturnal PSG—clues that have diagnostic value and also point clearly to the need for a multiple sleep latency test (MSLT).
Alyssa Cairns, PhD, research scientist at SleepMed Inc, studies these clues, particularly short onset REM periods (SOREMPs) during nighttime sleep. Did you know that a SOREMP in a nocturnal PSG has high specificity (99.2%!) and positive predictive value (92.1%) for narcolepsy?1 “Even if that patient is [at the sleep center] for screening of sleep apnea or PLMs [period limb movements], it should raise the red flag that something is amiss here. The brain is supposed to go into other stages of sleep first before REM, not REM before slow wave sleep,” Cairns emphasized during the webinar. The strange early transition to REM (within the first 15 minutes, versus between 90 and 120 minutes for controls) is likely symbolic of narcolepsy as a disorder of sleep-wake state control. Seeing a SOREMP during PSG also has diagnostic value, inasmuch as the International Classification of Sleep Disorders – Third Edition allows for narcolepsy diagnosis with 1 nocturnal short-onset REM during PSG and 1 short-onset REM during MSLT (versus the 2 short-onset REMs during MSLT that most sleep professionals are more familiar with).
A SOREMP during PSG should trigger an MSLT order. “If you see this as a technologist, consider this phenotype to be narcolepsy until proven otherwise,” Cairns said. Cairns also discussed other clues in PSGs, such as fragmented REM, more awakenings, and peculiar sleep stage transitions. Learn more via the free webinar at www.sleepreviewmag.com/resource-center/webinars.
Sree Roy is editor of Sleep Review. Email sroy[at]allied360.com.
1. Andlauer O, et al. Nocturnal Rapid Eye Movement Sleep Latency for Identifying Patients With Narcolepsy/Hypocretin Deficiency. JAMA Neurol. 2013;70(7):891-902.