Periodic Limb Movements during Sleep in Children, Adolescents, and Adults with Narcolepsy: A Cross-Sectional Study in China

Objectives. This study is aimed at determining the prevalence and effects of periodic limb movements during sleep (PLMS) on nighttime sleep and daytime sleepiness in children/adolescents and adults with narcolepsy. Methods. A total of 94 patients with narcolepsy were recruited in this study. They were classified into two groups including children/adolescents (<18 years, n = 41) and adults (>= 18 years, n = 53). All participants completed face-to-face interviews and underwent polysomnography assessment followed by multiple sleep latency test. Demographic, clinical, and sleep parameters were compared between narcoleptic patients with and without PLMS. Linear regression analysis was performed to determine the association between PLMS and sleep parameters. Results. Thirty-eight (40.4%) patients with narcolepsy were defined as having PLMS, and there was a higher prevalence of PLMS in the children/adolescents than in the adults with narcolepsy (56.1% vs. 28.3%, respectively, P = 0:006). Narcoleptic patients with PLMS had a significantly shorter total sleep time, lower sleep efficiency (SE), and more wakefulness after sleep onset (WASO) than those without PLMS in adults (all P < 0:05). After adjusting for the potential confounders, PLMS was significantly associated with lower SE (adjusted beta = -0:327; 95% CI: -0.608, 0.044; P = 0:025) and more WASO (adjusted beta = 0:330; 95% CI: 0.038, 0.520; P = 0:028) in adults with narcolepsy. Conclusions. There is a high prevalence of PLMS in narcolepsy, especially in children and adolescent patients. PLMS is associated with nighttime sleep disturbance in adults with narcolepsy but is not a risk factor for daytime sleepiness both in children/adolescents and adults with narcolepsy.