The Narcolepsy Severity Scale (NSS) is reliable and responsive to changes in the severity of narcolepsy type 1, according to study results published in Sleep.

According to researchers, a small proportion of patients with narcolepsy type 1 share the same 5 symptoms (excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, sleep paralysis, and disrupted nighttime sleep); however, it is unclear whether these symptoms affect daily functioning and quality of life in narcolepsy type 1. The NSS was recently developed to evaluate the severity, frequency, and impact of the 5 main narcolepsy symptoms in patients with this sleep disorder. The objective of this study was to define clinically relevant NSS score ranges, confirm its main performances, test whether its items should be weighted, and reassess its responsiveness to narcolepsy medications in patients with narcolepsy type 1.

In this study, researchers recruited 381 patients with narcolepsy type 1 (143 untreated patients and 238 treated patients) from the National Reference Center for Narcolepsy of Montpellier, France. All patients completed the NSS based on the last month of their experience with the sleep disorder and were asked questions about the frequency and intensity of symptoms and the impact of symptoms on daily life. The Epworth Sleepiness Scale (ESS) was used to assess the presence and severity of excessive daytime sleepiness, and logistic regression models were used to compare the ESS with different NSS items.

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