Periodic limb movements and restless legs syndrome in children with a history of prematurity

Polysomnographically Defined Restless Sleep Disorder and Periodic Limb Movements during Sleep in Children Born Prematurely

INTRODUCTION

Children born prematurely (<37 weeks' gestation) are at increased risk of perinatal complications, comorbidities, and iron deficiency. Iron deficiency is associated with restless legs syndrome and periodic limb movement disorder. In this study, we assessed the prevalence of restless sleep disorder (RSD) and elevated periodic limb movements during sleep (PLMS) in children born prematurely who underwent polysomnography.

METHODS

A retrospective chart review of sleep studies was conducted in children aged 1-18 years (median age 4 years) with a history of premature birth. Children with genetic syndrome, airway surgery, or tracheostomy were excluded. Three groups were compared: children with PLMS index >5, children with RSD, and children with neither elevated PLMS index nor RSD.

RESULTS

During the study, 2577 sleep studies were reviewed. Ninety-two studies fit our criteria and were included in the analysis. The median age at birth was 31 weeks, and the interquartile range (IQR) was 27-34 weeks. A total of 32 (34.8%) children were referred for restless sleep and 55 (59.8%) for snoring. After polysomnography, 18% were found to have a PLMS index >5/h, and 14% fit the criteria for restless sleep disorder (RSD). There were no statistically significant differences in PSG parameters among 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 the non-RSD/non-PLMS (median 2.0, IQR 0.8-4.5) groups.

CONCLUSIONS

There was an elevated frequency of RSD and elevated PLMS in our cohort of children born prematurely. Children born prematurely are at higher risk of iron deficiency which can be a contributor factor to sleep -related movement disorders. These results add new knowledge regarding the prevalence of RSD and PLMS in these children.

Sleep in children from northeastern Brazil with congenital Zika syndrome: assessment using polysomnography

STUDY OBJECTIVES

We performed this study to describe the characteristics of sleep in children with congenital Zika syndrome through polysomnographic assessment.

METHODS

Polysomnography with neurological setup and capnography was performed. Respiratory events were scored according to American Academy of Sleep Medicine criteria. Children were classified based on neuroclinical examination as having corticospinal plus neuromuscular abnormalities or exclusively corticospinal abnormalities. Neuroradiological classification was based on imaging exams, with children classed as having supratentorial plus infratentorial abnormalities or exclusively supratentorial abnormalities.

RESULTS

Of 65 children diagnosed with congenital Zika syndrome, sleep apnea was present in 23 children (35.4%), desaturation in 26 (40%), and snoring in 13 (20%). The most prevalent apnea type was central in 15 children (65.2%), followed by obstructive apnea in 5 (21.7%) and mixed type in 3 (13%). The average of the lowest saturation recorded was slightly below normal (89.1 ± 4.9%) and the mean partial pressure of end-tidal carbon dioxide value was normal. Periodic leg movements were present in 48 of 65 children. Lower ferritin levels were observed in 84.6% of children. Palatine and pharyngeal tonsils (adenoids) were small in most children and not associated with the presence of obstructive apnea. Ventriculomegaly and subcortical and nucleus calcification were the most frequent neuroimaging findings. Supratentorial and infratentorial anomalies were present in 26.7% (16 of 60) and exclusively supratentorial changes in 73.3% (44 of 60). In the neuroclinical classification, isolated corticospinal changes were more frequent and the mean peak in capnography was lower in this group. There was no difference regarding the presence of apnea for children in the neuroclinical and neuroradiological classification groups.

CONCLUSIONS

Sleep disorders were frequent in children with congenital Zika syndrome, with central sleep apnea being the main finding.

CITATION

Brandão Marquis V, de Oliveira Melo A, Pradella-Hallinan M, et al. Sleep in children from northeastern Brazil with congenital Zika syndrome: assessment using polysomnography. J Clin Sleep Med. 2023;19(10):1759-1767.

What do we know about the sleep effects of caffeine used to treat apnoea of prematurity? A systematic review of the literature

OBJECTIVE

Scientific scrutiny has proved the safety and benefits of caffeine to treat apnoea of prematurity (AOP). However, there is no consensus on the effects of this treatment on sleep, especially considering the key role of adenosine and early brain development for sleep maturation. We systematically reviewed studies with sleep as a primary and/or secondary outcome or any mention of sleep parameters in the context of caffeine treatment for AOP.

METHODS

We performed a systematic search of PubMed, Web of Science and the Virtual Health Library from inception to 7 September 2022 to identify studies investigating the short- and long-term effects of caffeine to treat AOP on sleep parameters. We used the PIC strategy considering preterm infants as the Population, caffeine for apnoea as the Intervention and no or other intervention other than caffeine as the Comparison. We registered the protocol on PROSPERO (CRD42021282536).

RESULTS

Of 4019 studies, we deemed 20, including randomised controlled trials and follow-up and observational studies, to be eligible for our systematic review. The analysed sleep parameters, the evaluation phase and the instruments for sleep assessment varied considerably among the studies. The main findings can be summarised as follows: (i) most of the eligible studies in this systematic review indicate that caffeine used to treat AOP seems to have no effect on key sleep parameters and (ii) the effects on sleep when caffeine is administered earlier, at higher doses or for longer periods than the most common protocol have not been investigated. There is a possible correlation between the caffeine concentration and period of exposure and negative sleep quality, but the sleep assessment protocols used in the included studies did not have high-quality standards and could not provide good evidence.

CONCLUSIONS AND IMPLICATIONS

Sleep quality is an important determinant of health, and better investments in research with adequate sleep assessment tools are necessary to guarantee the ideal management of children who were born preterm.

Periodic leg movements during sleep and iron status in infants with prematurity, Down syndrome and Prader-Willi syndrome

Sleep disturbances including bedtime problems and night awakenings are common during infancy. Polysomnography during the first years of life is performed mainly to rule out sleep-disordered breathing; however, sleep-related movement disorders can constitute a significant contributor to sleep disruption in this age group. Almost no studies have investigated the presence of periodic limb movements during sleep and underlying iron deficiency in infants, especially in those born preterm or with an underlying genetic syndrome. In this retrospective study we included infants 3-24 months referred for polysomnography for snoring or frequent nocturnal awakenings. All children had bloodwork (ferritin and haemoglobin) conducted within 3 months of the overnight sleep study. We studied 79 infants, including 31 (39.2%) full-term without diagnosis, 10 (12.7%) born premature, 16 (20.3%) with Down syndrome, 15 (19.0%) with Prader-Willi syndrome, and the remaining seven (8.9%) had various disorders. Compared with those with Down syndrome, Prader-Willi syndrome and full-term infants, those with prematurity showed a statistically significant elevated periodic limb movement index and lower ferritin levels than the other groups. Both ferritin (r = -0.18) and haemoglobin (r = -0.30) were negatively correlated with periodic limb movement index; however, this correlation reached statistical significance only for haemoglobin. Iron deficiency is associated with increased periodic leg movements during sleep in infants. Infants with prematurity had higher periodic limb movement index and lower ferritin levels than infants with Down syndrome, Prader-Willi syndrome or without diagnosis.

Sleep Deficiency and Pediatric Chronic Pain

Sleep deficiency in children is a public health concern, and it is highly comorbid in pediatric chronic pain conditions. Children may be particularly vulnerable to the deleterious effects of sleep deficiency, because comorbid sleep deficiency in chronic pain may further exacerbate already existent symptoms of pain, anxiety, depressions, daytime function, and increase health care use. Sleep deficiency is modifiable and integrating human-centered approaches into the development of sleep interventions is a pragmatic approach to partner with parents and children to provide them with the knowledge, motivation, and skills for setting and achieving goals, adapting to setbacks, and problem solving.

Perinatal antecedents of sleep disturbances in schoolchildren

STUDY OBJECTIVES

Prematurity has been associated with an increased risk for sleep apnea. However, sleep disturbances in children born preterm have not been extensively investigated. Considering that determinants of sleep may originate early in life, the potential impact of prematurity on sleep disturbances later in life could be important. To establish the role of prematurity on sleep disturbances in a cohort of schoolchildren that were born preterm and compare them with healthy controls.

METHODS

A cohort of 147 schoolchildren, 45 born at term (≥37 weeks) and 102 very preterm (<32 weeks), was recruited and evaluated at school age (5-9 years). The Pediatric Sleep Questionnaire (PSQ) and the Sleep Disturbance Scale for Children (SDSC) were used to assess sleep disturbances in different domains.

RESULTS

PSQ score was significantly higher in former preterm children (0.26 ± 0.18 vs. 0.18 ± 0.14 in controls; p = 0.004), and SDSC total score was also significantly different among groups (21.7 ± 11.6 vs. 14.1 ± 12.6; p < 0.001). Regression models showed significant mean differences in PSQ score, total SDSC score, and two SDSC subscale scores (i.e. sleep-wake transition disorders, sleep-breathing disorders, and sleep hyperhidrosis) even after adjustment for confounders. Maternal age and type of delivery were not significantly associated with total PSQ scores.

CONCLUSIONS

Sleep disturbances may originate early in life since children born preterm exhibit an increased risk for developing long-term sleep problems. These findings may have important implications for management of preterm children and for implementation of early interventions focused on optimizing sleep habits.

Sleep-Wake Disorders in Childhood

PURPOSE OF REVIEW

The presentation of sleep issues in childhood differs from the presentation in adulthood and may be more subtle. Sleep issues may affect children differently than adults, and distinct treatment approaches are often used in children.

RECENT FINDINGS

Sodium oxybate was approved by the US Food and Drug Administration (FDA) in October 2018 for an expanded indication of treatment of sleepiness or cataplexy in patients with narcolepsy type 1 or narcolepsy type 2 aged 7 years or older, with side effect and safety profiles similar to those seen in adults. Restless sleep disorder is a recently proposed entity in which restless sleep, daytime sleepiness, and often iron deficiency are observed, but children do not meet the criteria for restless legs syndrome or periodic limb movement disorder.

SUMMARY

Children's sleep is discussed in this article, including normal sleep patterns and effects of insufficient sleep. Sleep disorders of childhood are reviewed, including insomnia, obstructive sleep apnea, restless legs syndrome, parasomnias, narcolepsy, and Kleine-Levin syndrome. Children with neurologic issues or neurodevelopmental disorders frequently have sleep disorders arising from an interaction of heterogeneous factors. Further attention to sleep may often be warranted through a polysomnogram or referral to a pediatric sleep specialist. Sleep disorders may cause indelible effects on children's cognitive functioning, general health, and well-being, and awareness of sleep disorders is imperative for neurologists who treat children.

Preterm birth and risk of sleep-disordered breathing from childhood into mid-adulthood

BACKGROUND

Preterm birth (gestational age <37 weeks) has previously been associated with cardiometabolic and neuropsychiatric disorders into adulthood, but has seldom been examined in relation to sleep disorders. We conducted the first population-based study of preterm birth in relation to sleep-disordered breathing (SDB) from childhood into mid-adulthood.

METHODS

A national cohort study was conducted of all 4 186 615 singleton live births in Sweden during 1973-2014, who were followed for SDB ascertained from nationwide inpatient and outpatient diagnoses through 2015 (maximum age 43 years). Cox regression was used to examine gestational age at birth in relation to SDB while adjusting for other perinatal and maternal factors, and co-sibling analyses assessed for potential confounding by unmeasured shared familial factors.

RESULTS

There were 171 100 (4.1%) persons diagnosed with SDB in 86.0 million person-years of follow-up. Preterm birth was associated with increased risk of SDB from childhood into mid-adulthood, relative to full-term birth (39-41 weeks) [adjusted hazard ratio (aHR), ages 0-43 years: 1.43; 95% confidence interval (CI), 1.40, 1.46; P <0.001; ages 30-43 years: 1.40; 95% CI, 1.34, 1.47; P <0.001]. Persons born extremely preterm (<28 weeks) had more than 2-fold risks (aHR, ages 0-43 years: 2.63; 95% CI, 2.41, 2.87; P <0.001; ages 30-43 years: 2.22; 95% CI, 1.64, 3.01; P <0.001). These associations affected both males and females, but accounted for more SDB cases among males (additive interaction, P = 0.003). Co-sibling analyses suggested that these findings were only partly due to shared genetic or environmental factors in families.

CONCLUSIONS

Preterm-born children and adults need long-term follow-up for anticipatory screening and potential treatment of SDB.