Clinical and objective correlates of disrupted nighttime sleep in pediatric narcolepsy type 1

Objectives: Disrupted nocturnal sleep (DNS) is a common symptom in Narcolepsy type 1 (NT1) but remains understudied in pediatric populations. We aimed to identify factors associated with DNS complaint in children with NT1, and to evaluate treatment effect on this symptom. Methods: Eighty-seven consecutive NT1 children (14 ± 2.8y.o., 68 untreated), diagnosed according to ICSD3-TR criteria, underwent standardized evaluations with recording of clinical characteristics, self-questionnaires including the Pediatric-Narcolepsy Severity Scale (NSS-P), polysomnography (PSG), multiple sleep latency tests, and CSF orexin-A levels measurments. Among untreated patients, 41 were reevaluated after stable management. DNS was assessed using a single NSS-P item and categorized as absent/mild versus moderate/severe. Results: In the cross-sectional sample, 68 % untreated children reported DNS (mild, moderate or severe) on NSS-P. Untreated children with moderate/severe DNS (37 %) had higher NSS-P scores, more hallucinations, REM sleep parasomnias, insomnia and fatigue. In untreated patients, on PSG, higher indexes of periodic legs movements during sleep and microarousal were associated with DNS complaint. In the longitudinal sample, DNS improved in 34 % of all treated children: NSS-P scores and depressive and insomnia symptoms decreased, with less fragmented sleep on PSG (i.e. sleep/wake bouts, transitions, Wake/N1 indexes). However, no associations were found between DNS improvement, and clinical and PSG features. Conclusion: DNS complaint in pediatric NT1 is frequent, associated with disease severity, but with few PSG markers in untreated condition. It improves in one third of patients after management. Further studies are needed to determine optimal measures of DNS in narcolepsy across ages, to be implemented in the management strategy.