According to study results published in Neurology, the Pediatric Narcolepsy Severity Scale (NSS-P) is a valuable tool for measuring narcolepsy symptoms in children and adolescents of school age.
Narcolepsy type 1 (NT1) is a disabling neurological disorder that results from the irreversible destruction of hypothalamic orexin / hypocretin neurons. In the absence of curative treatments, treatment of these patients remains symptomatic. In a previous study, the NSS, a 15-point self-disclosure questionnaire, was validated in adults with NT1.
The Pediatric Version of the NSS (NSS-P) is designed to assess the frequency, severity, and consequences of NT1 symptoms in children and adolescents. The NSS-P rates the 5 main symptoms of narcolepsy, including excessive daytime sleepiness, cataplexy, hallucinations, sleep paralysis, and disturbed night sleep. After removing the item on the subject of driving, the total score of 14 items NSS-P was in the range from 0 to 54.
The aim of the current study was to validate the new score and assess its response to treatment.
The study population comprised 209 patients aged 6 to 17 years (41.15% girls; mean age 13.27 years) with NT1 from 2 National Reference Centers for Orphan Hypersomnolence Disorders in France. Of these, 160 patients completed the questionnaire, including 65 children and adolescents who completed it again in the follow-up: 33 patients the first time untreated and the second time under medication and 32 patients under the same treatment in both cases.
The psychometric properties of NSS-P, its internal consistency, content validity, reproducibility, and response to pharmacological treatment were satisfactory. The questionnaire proved to be a reliable tool to assess the severity of NT1 symptoms and their consequences and to identify clinically significant changes under medication in children aged 10 and over.
The factor analysis resulted in a 4-factor solution with good reliability, including 4 questions about sleep paralysis and hallucinations, 5 questions about daytime sleepiness, 3 questions about cataplexy and 2 questions about the refreshing effect of a sleep attack and night sleep.
The NSS-P total score was lower in the group of 92 treated patients than in the group of 68 untreated patients (mean score 23.32 and 27.03; mean difference 3.71).
The NSS-P total score was divided into 4 equal ranks to define different degrees of severity: 0 to 14 (easy; 13%), 15 to 28 (medium; 54%), 29 to 42 (severe; 29%) and 43 up to 54 (very difficult; 4%). The proportion of patients in the severe / very severe groups was higher in the untreated group than in the treated group (41% and 26%, respectively, P = 0.02).
The likelihood of self-reported excessive daytime sleepiness increased with the NSS-P score in both groups. The total NSS-P score was significantly associated with other self-reported ratings of sleepiness, fatigue, insomnia, and depressive symptoms.
The study had several limitations, including the lack of data on the reliability of the NSS-P in children under 10 years of age because these patients were excluded from the study, lack of data on self-reported rating scales, and a relatively small sample size used to evaluate the effect in different subgroups .
“[W]We validated a short tool for assessing the frequency, severity and consequences of NT1 symptoms in year10-year-old children and adolescents with four clinically relevant severity ranges. This scale is a relevant tool for improving and providing guidelines for NT1 management in pediatric populations. Its ease of administration, its good psychometric properties and its sensitivity to detecting symptom changes after treatment ensure the future use of NSS-P in clinical settings and research environments, ”concluded the study researchers.
Disclosure: Some study authors stated links with biotech, pharmaceutical, and / or device companies. For a full list of the author’s disclosures, see the original reference.
L. Barateau, M. Lecendreux, S. Chenini et al. Measuring Narcolepsy Symptoms in School-Age Children and Adolescents: the Pediatric Narcolepsy Severity Scale. Neurology. Published online May 24, 2021. doi: 10.1212 / WNL.0000000000012272