Restless Sleep Disorder and Periodic Limb Movements During Sleep in Children with a History of Prematurity

Introduction: Children with history of prematurity are at higher risk of complications, comorbidities and iron deficiency, including restless legs syndrome and periodic limb movements of sleep (PLMS). In this study we assess the prevalence of restless sleep disorder and PLMS in children with history of prematurity. Methods: Retrospective chart review of sleep studies in children aged 1-18 years, with history of prematurity, from July 2021 to July 2022 at Seattle Children's Hospital. Only diagnostic studies in children without diagnosis of a genetic syndrome or airway surgery were included. Results: During the study, 2,577 sleep studies were conducted, 162 were in children with history of prematurity (6%): 25 were split or titration studies (14%), 29 children had syndromes (Down, Prader Willi, Wiedmann Beckmann, Achondroplasia), 4 tracheostomy studies, 6 in infants aged < 12 months and 6 were post airway intervention. Ninety-two diagnostic studies were included in analysis. Median birth age was 31 weeks, interquartile range (IQR) 27-34 weeks. Thirty-two (34.8%) children were referred for restless sleep and 55 (59.8%) for snoring; 18% had PLMS index >5/hour, 14% fit the criteria for restless sleep disorder (RSD). There were no statistically significant differences in PSG parameters between the children with RSD, PLMS and the remaining group, except for lower obstructive apnea/hypopnea index (Kruskal-Wallis ANOVA 8.621, p=0.0135) in the RSD group (median 0.7, IQR 0.3-0.9) than in the PLMS (median 1.7, IQR 0.7-3.5), or than in the nonRSD/nonPLMS group (median 2.0, IQR 0.8-4.5). Altogether, children with RSD and those with PLMS had restless sleep as an indication for the sleep study in 70% of cases while snoring was the indication in only 26.7% of them. Conclusion: We have previously reported that in the Seattle Children's Hospital Sleep Center the prevalence of RSD is 7.7% and that of PLMS is 9.3%; in this new analysis we found a higher frequency of RSD and elevated PLMS in children with history of prematurity. Premature children are higher risk of iron deficiency, among other complications and comorbidities. These new results confirm the previous reports of increased PLMS and add new knowledge on the prevalence of RSD in these children