Narcolepsy-Characteristics of those in the Borderland-We Need a Better Diagnostic Tool

Narcolepsy-Characteristics of those in the Borderland-We Need a Better Diagnostic Tool Purpose: The criteria for the diagnosis of narcolepsy changed when the 2nd edition of the International Classification of Sleep Disorders supplanted the first edition (ICSD-1). The impact of using the updated criteria is unknown. We thus compared the characteristics of a population of patients diagnosed using ICSD- 2 with those that only met ICSD-1 criteria. Minimum criteria for narcolepsy in ICSD-1 are sleepiness with cataplexy, sleep paralysis, or hypnogogic hallucinations plus sleep latency <10 minutes or REM latency <20 min on polysomnography. ICSD-2 requires sleepiness with cataplexy or a positive MSLT (MSLT-SL ≤ 8 min and SOREMPs ≥ 2). Methods: The records of 148 subjects with suspected narcolepsy were reviewed. Seventy subjects were excluded because of other diagnoses or use of REM suppressants. 59 patients were diagnosed on the basis of cataplexy (54%) or positive MSLT (55%). The remaining 19 patients without cataplexy or positive MSLT fulfilled the minimal criteria using ICSD-1. Results: The anthropometrics, narcolepsy symptoms including refreshing naps, Epworth sleepiness scores and sleep bioparameters were comparable between patient with and without cataplexy.