Sleep measurement and monitoring in children with Down syndrome: a review of the literature, 1960-2010

Sleep problems of children with Down syndrome in northern China

BACKGROUND

Limited research has looked at the present-day sleep problems among Chinese children with Down syndrome (DS). This study aimed to investigate the situation of the sleep problems of school-aged children with DS in northern China.

METHODS

Parents of children with DS were a convenience sample recruited through the special education schools of Shandong Province in China. The Chinese version of the Children's Sleep Habits Questionnaire was applied to assess the sleep problems of children with DS.

RESULTS

Parents of 334 children with DS reported the average sleep duration was 9.7 (9.3-10.2) hours per night, and 62.0% of children with DS were reported sleeping less than 10 h per night. Additionally, the total prevalence rate of sleep problems among children with DS was 69.8%. Sleep-disordered breathing (59.2%), sleep duration (33.8%) and bedtime resistance (32.0%) were the three most commonly reported sleeping problems. Younger children with DS (age 6-8 years) had severe problems with bedtime resistance, sleep anxiety and parasomnias than older children with DS (age 9-12 years) (all P < 0.05).

CONCLUSION

Sleep problems are prominent among children with DS in northern China and are worthy of attention. Caregivers and health professionals should raise awareness of sleep problems in this group of children and implement targeted interventions to improve their sleep quality as early as possible.

A clinical-translational review of sleep problems in neurodevelopmental disabilities

Sleep disorders are very common across neurodevelopmental disorders and place a large burden on affected children, adolescents, and their families. Sleep disturbances seem to involve a complex interplay of genetic, neurobiological, and medical/environmental factors in neurodevelopmental disorders. In this review, we discuss animal models of sleep problems and characterize their presence in two single gene disorders, Rett Syndrome, and Angelman Syndrome and two more commonly occurring neurodevelopmental disorders, Down Syndrome, and autism spectrum disorders. We then discuss strategies for novel methods of assessment using wearable sensors more broadly for neurodevelopmental disorders in general, including the importance of analytical validation. An increased understanding of the mechanistic contributions and potential biomarkers of disordered sleep may offer quantifiable targets for interventions that improve overall quality of life for affected individuals and their families.

Siblings' experiences of sleep disruption in families with a child with Down syndrome

OBJECTIVE

Adverse effects of sleep disruption are identified in parents who live with a child with Down Syndrome (DS), yet there is no research on siblings' experiences. This study addresses this knowledge gap.

DESIGN

A qualitative research study using semi-structured interviews to understand the experiences of siblings of a child with DS and sleep difficulties from the perspectives of parents and siblings.

PARTICIPANTS

Eleven siblings aged 5-15 years old, and 11 parents, from 8 families with a child with DS in Australia.

METHODS

Semi-structured sibling interviews explored what it was like to have a sibling with DS and sleep difficulties; the participant's own sleep; how their sleep affected how they felt during the day; how sleep impacted their family; and advice that they would give to other siblings. Parent interviews included similar topics; here we report on excerpts in which parents reference siblings. Interviews were audio recorded, transcribed verbatim, and analyzed using a reflexive thematic analysis.

RESULTS

Siblings and parents acknowledge sleep disruption for siblings; yet sleep disruption is normalized, viewed with acceptance and inevitability. Siblings report adverse effects from sleep disruption, view sleep in a relational way, and cope with sleep disruption. Parents can underestimate siblings' sleep disruption and are uncertain whether siblings' symptoms result from sleep disruption or other causes.

CONCLUSIONS

Siblings of a child with DS experience sleep disruption and may be at risk of developing long-term health problems without focused support.

Contactless sleep monitoring using the Sonomat in children with Down syndrome

BACKGROUND

Children with Down syndrome (DS) require multiple sleep studies throughout childhood to diagnose and monitor sleep disordered breathing (SDB). Previous research suggests sensors applied during polysomnography (PSG) are poorly tolerated by children with DS. The Sonomat is a contactless device previously validated in typically developing children, and adult populations. Our study aimed to compare simultaneous Sonomat and PSG recordings in children with DS to determine the suitability of the Sonomat for use in this population.

METHODS

Fifty children with DS undergoing diagnostic PSG were recruited from the Queensland Children's Hospital sleep laboratory. Agreement for sleep and respiratory parameters were assessed using concordance correlation coefficients (CCC), while detection and classification of SDB were assessed using indicators such as sensitivity, specificity, likelihood ratios, and receiver operator characteristic curves.

RESULTS

Comparison of parameters including the apnea-hypopnea index (CCC=89%; 95%CI 76, 93), and obstructive events index (CCC=74%; 95%CI 44, 88) showed reasonable agreement between Sonomat and PSG. The Sonomat showed outstanding ability to differentiate between the presence and absence of SDB (area under the curve [AUC]=0.97; 95%CI 0.93, 1.00), though we are uncertain of its ability to classify SDB profile and severity due to sample size limitations resulting in wide confidence intervals.

CONCLUSIONS

The easy-to-use, non-invasive nature of the Sonomat make it ideal for use in the screening of SDB in children with DS. Further data are needed to determine its suitability for classifying SDB profile and severity, including within the home, and for its use in other neurodevelopmental groups.

Developmental changes in obstructive sleep apnea and sleep architecture in Down syndrome

BACKGROUND

Down syndrome (DS, also known as Trisomy 21) is a condition associated with abnormal neurodevelopment and a higher risk for sleep apnea. Our study sought to better understand and characterize the age-related developmental differences in sleep architecture and obstructive sleep apnea (OSA) severity in children with DS compared to euploid individuals.

METHODS

Retrospective review of polysomnograms in over 4151 infants, children, and adolescents in the pediatric sleep center at Children's National Hospital in Washington D.C. (0-18 years) including 218 individuals with DS.

RESULTS

The primary findings of our study are that: (1) severe OSA (obstructive apnea-hypopnea index ≥ 10/h) was more prevalent in the DS group (euploid 18% vs. DS 34%, p < 0.001) with the highest OSA severity being present in young children (<3 years old) and adolescents (>10 years old), (2) abnormalities in sleep architecture in children with DS were characterized by a prolonged rapid-eye movement (REM) sleep onset latency (SOL) (euploid 119 min vs. DS 144 min, p < 0.001) and greater arousal indexes (euploid 10.7/h vs. DS 12.2/h, p < 0.001), (3) developmental changes in the amount of REM sleep or slow wave sleep were not different in DS individuals relative to euploid children, (4) multivariate analyses showed that OSA and REM sleep latency differences between DS and euploid individuals were still present after adjusting by age, biological sex, and body mass index.

CONCLUSION

Severe OSA is highly prevalent in children with DS and follows an age-dependent "U" distribution with peaks in newborns/infants and children >10 years of age. Children with DS also have disturbances in sleep architecture characterized by a longer REM SOL and elevated arousal indexes. As sleep cycle generation and continuity play crucial roles in neuroplasticity and cognitive development, these findings offer clinically relevant insights to guide anticipatory guidance for infants, children, and adolescents with DS.

Candidate genes for obstructive sleep apnea in non-syndromic children with craniofacial dysmorphisms - a narrative review

Pediatric obstructive sleep apnea (POSA) is a complex disease with multifactorial etiopathogenesis. The presence of craniofacial dysmorphisms influencing the patency of the upper airway is considered a risk factor for POSA development. The craniofacial features associated with sleep-related breathing disorders (SRBD) - craniosynostosis, retrognathia and micrognathia, midface and maxillary hypoplasia - have high heritability and, in a less severe form, could be also found in non-syndromic children suffering from POSA. As genetic factors play a role in both POSA and craniofacial dysmorphisms, we hypothesize that some genes associated with specific craniofacial features that are involved in the development of the orofacial area may be also considered candidate genes for POSA. The genetic background of POSA in children is less explored than in adults; so far, only one genome-wide association study for POSA has been conducted; however, children with craniofacial disorders were excluded from that study. In this narrative review, we discuss syndromes that are commonly associated with severe craniofacial dysmorphisms and a high prevalence of sleep-related breathing disorders (SRBD), including POSA. We also summarized information about their genetic background and based on this, proposed 30 candidate genes for POSA affecting craniofacial development that may play a role in children with syndromes, and identified seven of these genes that were previously associated with craniofacial features risky for POSA development in non-syndromic children. The evidence-based approach supports the proposition that variants of these candidate genes could lead to POSA phenotype even in these children, and, thus, should be considered in future research in the general pediatric population.

Sleep assessment in adults with Down syndrome: correlation between functionality and polysomnographic findings

BACKGROUND

 Sleep disorders have a negative impact on health, being associated with neurocognitive problems, cardiovascular diseases and obesity, influencing children's development and learning.

OBJECTIVE

 To assess the sleep pattern of people with Down syndrome (DS) and correlate changes with functionality and behavior.

METHODS

 A cross-sectional study was conducted to evaluate the sleep pattern in adults with DS > 18 years old. Twenty-two participants were assessed using the Pittsburgh Sleep Quality Index, the Functional Independence Measure and the Strengths and Difficulties Questionnaire, and the 11 who presented indications of disorders by the screening questionnaires were referred to polysomnography. Statistical tests were performed using a significance level of 5%, including sample normality tests and correlation tests (sleep and functionality).

RESULTS

 Impairment in sleep architecture was found due to an increase in the rate of awakenings in 100% of the participants, a decrease in the number of slow waves, and a high prevalence of sleep disordered breathing (SDB), with higher averages in the Apnea and Hypopnea Index (AHI) in the group. There was a negative correlation between sleep quality and global functionality (p = 0.011) and the motor (p = 0.074), cognitive (p = 0.010), and personal care (p = 0.072) dimensions in the group. Global and hyperactivity behavior changes were related to worse sleep quality (p = 0.072; p = 0.015, respectively).

CONCLUSION

 There is an impairment in the sleep quality of adults with DS, with an increase in the rate of awakenings, a decrease in the number of slow waves, and a high prevalence of SDB affecting this population in the functional and behavioral aspects.

Obstructive Sleep Apnoea in Children with Down Syndrome: A Multidisciplinary Approach

A comprehensive evaluation of obstructive sleep apnoea (OSA) may allow for the development of more efficient management of Down syndrome (DS). We aimed to evaluate the effect of a multidisciplinary approach to DS with OSA. A total of 48 DS children aged 4−12 years were prospectively investigated with nasal endoscopy, orthodontic examination, and overnight polygraphy (PG); the Italian Child Sleep Habits Questionnaire (CSHQ-IT) was filled out by the mothers. The total CSHQ-IT score was 63 (96% of children reporting sleep problems). The major ear, nose, and throat characteristics were enlarged palatine tonsils (62%), adenoid tonsils (85%), and chronic rhinosinusitis (85%). DS children showed orthognathic profile in 68% of cases, class I relationship in 63%, and cross-bite in 51%. PG revealed OSA in 67% of cases (37% mild, 63% moderate−severe). The oxygen desaturation index (ODI) was higher in the group with OSA (5.2) than with non-OSA (1.3; p < 0.001). The ODI was higher (p = 0.001) and SpO2 lower (p = 0.03) in children with moderate−severe OSA than with mild OSA. The apnoea−hypopnea index (AHI) and percentage time with SpO2 < 90% were higher in DS children with grade III than with grade I or II adenoids (5 vs. 1, p = 0.04, and 1.2 vs. 0.1, p = 0.01, respectively). No significant correlations were found between PG and the total CSHQ-IT score or orthodontic data. However, children showing associated cross-bite, grade III adenoids and size 3 or 4 palatine tonsils showed higher AHI and ODI than those without (p = 0.01 and p = 0.04, respectively). A coordinated multidisciplinary approach with overnight PG is a valuable tool when developing diagnostic protocols for OSA in DS.

Characteristics of sleep-disordered breathing in children with down syndrome - A comparison with typically developing children

Background

Compared with typically developing control children (CC), children with Down syndrome (DS) frequently exhibit sleep-disordered breathing (SDB) and unusual sleep postures (USPs). No studies have directly compared SDB-related signs and symptoms, SDB-related parameters, and USPs between children with DS and CC. This study aimed to evaluate the prevalences of SDB and USPs in children with DS and CC.

Methods

We analyzed SDB-related parameters measured via overnight pulse oximetry and questionnaires administered to parents on SDB-related signs and symptoms, including sleeping postures. Estimated SDB was defined as a 3% oxygen desaturation index (ODI) ≥5 dips/h.

Results

Fifty-one children with DS (4–5 years: N = 12, 6–10 years: N = 23, 11–15 years: N = 16) and sixty-three CC (4–5 years: N = 18, 6–10 years: N = 27, 11–15 years: N = 18) were included. The prevalence of estimated SDB and observed USPs was higher in children with DS than in CC (p < 0.0001). Among children aged 11–15 years old, but not those aged 4–5 and 6–10 years old, frequency of arousal and apnea (p = 0.045 and p = 0.01, respectively) were higher in children with DS than in CC. Multivariate analyses showed that DS was associated with SDB-related signs and symptoms, estimated SDB, 3% ODI, average oxygen saturation (SpO₂), and nadir SpO₂, while USPs were associated only with higher values of SpO₂ <90%.

Conclusions

Estimated SDB tended to increase in children with DS but decreased in CC with growth. USPs were more frequent in children with DS than in CC, especially in older children. USPs might indicate severe hypoxemia due to SDB in DS.

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The difference of prevalence of SDB/USPs between DS and CC was evaluated.

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The prevalence of SDB increased with growth in the DS but not in the CC.

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USPs, taking to escape from suffocation by SDB, were frequently observed in older DS.

Neurocognitive evaluation of children with down syndrome and obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) treatment has been shown to improve cardiac behavioral and cognitive functions in typically developing children. Early OSAS diagnosis in children with Down syndrome (DS) would be important to prevent its complications, especially cognitive ones, but remains overlooked. The main objective of our study was to assess the cognitive function of children with DS, with and without OSAS. The second objective was to determine the impact of the therapeutic intervention on the cognitive function of children with OSAS. This study included 41 children with DS who underwent polysomnography for OSAS diagnosis and a cognitive evaluation. They were aged between 3.4 and 17.3 years and 24 (59%) were boys. Their median OAHI was 2.6 (0-31)/h of sleep, 30 (73%) were diagnosed with OSAS (15 had mild OSAS, and 15 had moderate/severe OSAS). Some scores of the Raven's colored progressive matrices were negatively correlated with the respiratory arousal index, OAHI tended to be positively correlated with Reiss behavioral problems. 24 (59%) patients received a treatment. Even if we were unable to demonstrate this formally due that only 16 children (39%) accepted a follow-up visit, some displayed improvement in their neuropsychological scores, especially those with moderate/severe OSAS after treatment. Children with DS have low intellectual abilities and more risk of developing OSAS compared to the general population, which may lead to further neurocognitive impairment. Early screening and management are important in this population to prevent any further neurocognitive delay in their development.

Parents' Experiences of Having a Child with Down Syndrome and Sleep Difficulties

OBJECTIVES

Sleep disorders are prevalent in children with Down Syndrome (DS). However, sleep treatment is not always readily accessed by this group. This study aims to understand families' experiences of having a child with DS and sleep difficulties, and in particular, their healthcare experiences, with the goal of informing practice improvements.

METHODS

We conducted semi-structured interviews with 34 parents (fathers n = 4 and mothers n = 30) with open-ended questions about parents' experiences of sleep, family dynamics, and healthcare. We operationalized a reflexive Thematic Analysis.

RESULTS

Parents normalized their experiences of having a child with DS and sleep problems. Parents acknowledged that sleep disruption has adverse and pervasive impacts on their wellbeing and family dynamics, but also found this difficult to identify as a health problem. They accepted sleep difficulties as a regular part of bringing up any child, particularly one with a disability. When they did seek treatment for their child's sleep difficulties, parents often reported encountering insensitive and inadequate care and described that, at times, healthcare professionals also normalized children's sleep difficulties, resulting in sub-optimal treatment. This included at times failure to refer to tertiary sleep medicine services when required.

CONCLUSIONS

Parents' and healthcare professionals' normalization of sleeping difficulties denies that they are both deleterious and modifiable. Practice implications include raising healthcare professionals' awareness of the importance of proactively addressing sleep, with sensitivity to families' normalization strategies, recognizing that families may require prompting to report concerns.

Brain circuit pathology in Down syndrome: from neurons to neural networks

Down syndrome (DS), a genetic pathology caused by triplication of chromosome 21, is characterized by brain hypotrophy and impairment of cognition starting from infancy. While studies in mouse models of DS have elucidated the major neuroanatomical and neurochemical defects of DS, comparatively fewer investigations have focused on the electrophysiology of the DS brain. Electrical activity is at the basis of brain functioning. Therefore, knowledge of the way in which brain circuits operate in DS is fundamental to understand the causes of behavioral impairment and devise targeted interventions. This review summarizes the state of the art regarding the electrical properties of the DS brain, starting from individual neurons and culminating in signal processing in whole neuronal networks. The reported evidence derives from mouse models of DS and from brain tissues and neurons derived from individuals with DS. EEG data recorded in individuals with DS are also provided as a key tool to understand the impact of brain circuit alterations on global brain activity.

Global, Regional, and National Burden and Trends of Down Syndrome From 1990 to 2019

Introduction: Down syndrome (DS) is the leading cause of genetically defined intellectual disability and congenital birth defects worldwide. A large population of people diagnosed with DS globally is posing an enormous socioeconomic burden. However, the global burden and trends of DS have not been reported.

Methods: Based on the data from the Global Burden of Disease database in 2019, we analyzed the incidence, prevalence, disability-adjusted life years (DALYs), and death of DS from 1990 to 2019 according to sex, age, regions, and social-demographic index (SDI). Then, age-standardized rates (ASRs) and estimated annual percentage change (EAPC) of these aforementioned indexes were calculated to evaluate the temporal trend of DS. Finally, the association of SDI with DS epidemiological parameters was assessed.

Results: In the past 30 years, the incident cases, age-standardized incident rate (ASIR), and age-standardized prevalent rate (ASPR) of DS first decreased slightly and subsequently increased globally. The number of prevalent cases increased steadily, while the number and age-standardized rate (ASRs) of DALYs and deaths decreased gradually from 1990 to 2019. In the meantime, disease burdens were different across various SDI regions. The prevalent cases and ASPR for both sexes were increasing in all SDI regions except for the high-middle SDI region. At the national level, Brunei Darussalam, Ireland, and Haiti were the top three countries with the highest ASIR in 2019. Georgia was in the top three with the highest increase in ASRs of four parameters, while Serbia was consistently ranked in the top three with fastest declining. Furthermore, we found that ASIR and ASPR were positively correlated with SDI, yet the age-standardized DALYs and age-standardized death rate (ASDR) were negatively correlated with SDI.

Conclusion: In the past 30 years, the burden and trends of DS were heterogeneous across different regions and countries with different sociodemographic characteristics. Great improvements had been achieved in reducing DALYs and deaths globally. However, the increased number and ASRs of incident and prevalent cases in some regions, especially in low SDI regions, were contributing to numerous challenges to public health. The findings may provide valuable information to the development or implementation of more effective measures.

Improvement of obstructive sleep apnea in a child with Down syndrome with rapid palatal expansion

Children with Down syndrome (DS) have distinct orofacial structures that predispose them to sleep-disordered breathing. The management options for obstructive sleep apnea (OSA) include continuous positive airway pressure, adenotonsillectomy, mandibular advancement, and maxillary expansion. However, most of these treatment options are less effective or less viable for children with DS. Rapid maxillary expansion (RPE) with a fixed orthodontic appliance is a viable alternative for DS patients because it separates the mid-palatal suture and dilates the airway, regardless of the patient's adherence. We present a case of a 15-year-old boy with DS and severe OSA, which dramatically improved with RPE and subsequent orthodontic treatment. Although only the short-term changes have been presented in this report, this case emphasizes the need for further discussions on the viability of RPE for treating OSA in children with DS.

Pulse transit time as a diagnostic test for OSA in children with Down syndrome

STUDY OBJECTIVES

Children with Down syndrome (DS) are at risk of obstructive sleep apnea (OSA), but the access to sleep lab polysomnography (PSG) is limited. Simplified techniques are needed, such as polygraphy coupled with pulse transit time (PTT-PG) that detects respiratory events and the total autonomic arousals index (PTTAI). Our objective was to assess the ability of PTT-PG compared with PSG to diagnose OSA in children with DS.

METHODS

In this prospective multicenter study, patients with DS underwent a full-night PSG coupled with PTT. Sleep questionnaires (Sleep Disturbance Scale for Children and Pediatric Sleep Questionnaire) were filled by parents. PSG and PTT-PG results were compared to test their sensibility and specificity to diagnose OSA.

RESULTS

A total of 53 patients with DS were included; their median age was 9.3 years. An obstructive apnea-hypopnea index (OAHI) by PSG > 1 event/h was found in 36 (68%) patients, OAHI was > 1 and < 5 events/h in 18 patients (34%), ≥ 5 and < 10 events/h in 11 patients (21%), and ≥ 10 events/h in 7 patients (13%). OAHI was larger on PSG than on PTT-PG (P = .0005). For OSA diagnosis, the sensitivity was excellent for OAHI by PTT-PG if the added total PTTAI was > 1 event/h (1.0) and the specificity was high for the Pediatric Sleep Questionnaire (0.88) and OAHI > 1 event/h on PTT-PG (1.0).

CONCLUSIONS

More than two-thirds of children with DS referred for screening by a genetics specialist had OSA diagnosed by PSG. With its excellent sensitivity and specificity, PTT-PG could be a good and simplified alternative to PSG to diagnose OSA in children with DS.

CITATION

Ioan I, Weick D, Sevin F, et al. Pulse transit time as a diagnostic test for OSA in children with Down syndrome. J Clin Sleep Med. 2022;18(1):119-128.

Obstructive sleep apnea in children with Down syndrome: is it possible to predict severe apnea?

The objectives are to explore the demographic and polysomnographic features of children with Down syndrome and to determine the predictive factors associated with severe sleep apnea. A total of 81 children with Down syndrome referred for full-night polysomnography were analyzed. In addition, parental interviews were performed for each child. Data were available for 81 children, with a mean age of 4.8 years. Severe obstructive sleep apnea was determined in 53.1%. Age, sex, exposure to second-hand smoke, clinical findings, anthropometric features, and the presence of comorbidities were not predictors of severe obstructive sleep apnea. Children who were exposed to second-hand smoke had more sleep-related symptoms. Even in children without symptoms, the prevalence of severe obstructive sleep apnea was 40%. Moreover, 86% of parents had no previous information regarding possible sleep breathing disorders in their children. Clinically significant central apnea was present in 10 patients (12.3%).Conclusion: Our results demonstrate that severe obstructive sleep apnea is common in children with Down syndrome, even in children without a history of symptoms of sleep apnea. It is not possible to predict patients with severe apnea; thus, screening of children with Down syndrome beginning from young ages is very important. Central apneas could be a part of the spectrum of sleep abnormalities in Down syndrome.

Sleep, Function, Behaviour and Cognition in a Cohort of Children with Down Syndrome

Objective: To describe the sleep problems experienced by children with Down syndrome attending a tertiary sleep clinic and relationship with behaviour, function and cognition. Methods: Data were collected from children with Down syndrome aged 3–18 years old. Carers completed the Abbreviated Child Sleep Habits Questionnaire, Child Behaviour Checklist and Life-Habits Questionnaire at enrolment. Cognitive assessment (Stanford-Binet 5) was undertaken by a trained psychologist. Children received management for their sleep problem as clinically indicated. Results: Forty-two subjects with a median age of 6.8 years (Interquartile Range-IQR 4.5, 9.8) were enrolled. A total of 92% were referred with snoring or symptoms of Obstructive Sleep Apnoea (OSA), with 79% of those referred having had previous ENT surgery. Thus, 85% of all participants underwent a sleep study and 61% were diagnosed with OSA (OAHI ≥ 1/h). Based on questionnaires, 86% of respondents indicated that their child had a significant sleep disorder and non-respiratory sleep problems were common. Non-respiratory problems included: trouble going to sleep independently (45%), restless sleep (76%), night-time waking (24%) and bedtime resistance (22%). No significant correlations were found between sleep measures (behavioural and medical sleep problems) and the behavioural, functional or cognitive parameters. Conclusion: Sleep disorders were very common, especially non-respiratory sleep problems. OSA was common despite previous surgery. No association was found between sleep-related problems (snoring, sleep-study-confirmed OSA or non-respiratory sleep problem) and parent-reported behavioural problems, functional impairments or intellectual performance. This may reflect limitations of the measures used in this study, that in this population ongoing problems with daytime function are not sleep related or that a cross-sectional assessment does not adequately take into account the impacts of past disease/treatments. Further research is required to further evaluate the tools used to evaluate sleep disorders, the impact of those disorder on children with Down syndrome and interventions which improve both sleep and daytime function.

The impact of sleep problems on functional and cognitive outcomes in children with Down syndrome: a review of the literature

STUDY OBJECTIVES

The aim of this review was to summarize the existing literature on the association between sleep problems and cognition, function, and behavior in children with Down syndrome.

METHODS

Embase, PubMed, CINAHL, and PsychINFO databases were searched to retrieve all studies published between 1990 and 2018 that evaluated the relationship between sleep and cognition, function, or behavior in children with Down syndrome.

RESULTS

Fifteen articles were included, which were mostly of a cohort or case-controlled design. Five articles addressed sleep and cognition only, 6 reported on sleep and behavior, and only 1 reported on sleep and functional ability. Three papers evaluated sleep and both cognition and behavior. Findings varied across studies with methodological differences, making it difficult to directly compare results. The association between sleep and behavior or cognition in children with Down syndrome remains uncertain, but a large study in 110 children provides strong evidence of a negative impact of sleep disorders on the accomplishment of daily life habits.

CONCLUSIONS

The impact of coexisting sleep disorders in children with Down syndrome has not been widely studied, with only 15 relevant studies found through an extensive literature review. Large well-designed studies are required to fully understand this relationship further. This is important as sleep-disordered breathing and difficulties with sleep patterns and routines are highly prevalent in children with Down syndrome. Sleep may be one of the few treatable factors that can assist in improving long-term outcomes in this population.

The 24-Hour Movement Guidelines and Body Composition Among Youth Receiving Special Education Services in the United States

BACKGROUND

The purposes of this study were to examine the proportions of youth receiving special education services in the United States who individually and jointly met physical activity, screen time, and sleep duration guidelines, and to examine the impact of meeting none, one, two, and three of the guidelines on overweight and obesity.

METHODS

This cross-sectional analysis utilized data from the 2016 to 2017 National Survey for Children's Health data set on 3582 youth aged 10-17 years who received special education services. The frequency of the participants' compliance with the 24-hour movement guidelines and body weight status (based on the age- and sex-specific percentile cutoffs) were estimated. Meeting guidelines was defined as: 9-11 hours/night (5-13 y) or 8-10 hours/night (14-17 y) of sleep, ≤120 minutes per day of screen time, and ≥60 minutes per day of moderate to vigorous physical activity. A multinomial logistic regression analysis was conducted to estimate the impact of meeting none, one, two, or three guidelines on body weight status, adjusted for potential confounders.

RESULTS

Overall, 8.1% of youth met all three guidelines, 42.0% met two guidelines, 38.0% met one guideline, and 11.9% did not meet any guideline. Meeting all three guidelines was associated with an approximately 50% decreased likelihood of overweight than meeting no guideline, or sleep or screen time guidelines independently.

CONCLUSIONS

This study extends the 24-hour movement framework to children receiving special education services and should prompt the continued study of its utility for understanding health disparities experienced by this population.

Sleep-related learning in Williams Syndrome and Down's Syndrome

This chapter addresses sleep research challenges for the study of neurodevelopmental disorders drawing upon two disorders such as Down Syndrome and Williams syndrome. General sleep problems are outlined here, however particular consideration is given to the syndrome-specific issues or challenges that may be crucial to advancing our understanding of sleep-related cognitive and behavioral issues.

Sleep problems in Australian children with Down syndrome: the need for greater awareness

BACKGROUND

Children with Down Syndrome (DS) have a high prevalence of obstructive sleep apnoea (OSA). Non-respiratory sleep disorders also occur commonly but are less well recognised. This cross-sectional study evaluates the prevalence of sleep difficulties in a community sample of Australian children with DS (DS_comm), using the Children's Sleep Habits Questionnaire (CSHQ), and compares them to children referred to the sleep clinic (DS_ref). To our knowledge this is the first study to have reported prevalence of sleep problems in Australian children with DS and to compare a community and referred group of children with DS directly.

METHODS

The CSHQ was completed by parents of children with DS recruited from the community (DS_comm) via survey distributed by Down syndrome Queensland and Australia. A second group was recruited through the tertiary sleep clinic at our institution (DS_ref) and completed the same questionnaire on enrolment. Data from these groups was compared.

RESULTS

There were 76 participants in the DS_comm group (57% male; median age 9.7yrs) and 42 participants in the DS_ref group (50% male; median age 6.97yrs). The overall prevalence of sleep disturbances was 90.9% in the DS_comm group, and 85.7% in the DS_ref group (p = 0.54). There was a statistically significant difference in the mean total CSHQ score, with the DS_comm having the higher score (p = 0.023).

CONCLUSIONS

This study reports a high prevalence of sleep problems in both a community and referred group of Australian children with DS and suggests that there are many children with DS with sleep problems, particularly non-respiratory difficulties, who are potentially not receiving adequate treatment.

Outcome of drug induced sleep endoscopy directed surgery in paediatrics obstructive sleep apnoea: A systematic review

INTRODUCTION

Paediatrics obstructive sleep apnoea have been discussed to a great degree over the recent years and remains a conundrum till date. The advent of instrumentation has aided upper airway evaluation in determining the site and degree of upper airway collapse for targeted and effective surgical planning. The literature was reviewed to determine the outcome of Drug Induced Sleep Endoscopy (DISE) directed surgery in children with obstructive sleep apnoea.

MATERIAL AND METHODS

A literature search was conducted for the period from January 2000 to December 2019 by using a number of medical literature data bases including Scopus, PubMed and Embase. The following search words were used either individually or in combination: drug-induced sleep endoscopy, sleep endoscopy directed surgery, paediatrics sleep apnoea. The search was conducted over a month period (December 2019). Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Cochrane Handbook for Systematic Reviews of Interventions were followed when possible.

RESULTS

Seven clinical research articles were selected based on our objective and selection criteria. Seven studies were of level III evidence: retrospective, case-control and prospective series. Altogether, there were 996 patients with male predominance; 61%. Over 10% of patients (133 patients) were found to have comorbidities or were syndromic. The mean age of patient was 6 years and majority (87.6%) of our patients were found to be surgically naïve, that is, no previous surgical procedures were performed for OSA. Surgical decision was changed in 295 patients (30%) following DISE. Post intervention outcomes were objectively revealed in 4 studies. Most of our patients underwent a multilevel surgery based on DISE (86%). Complications were documented in 3 studies.

CONCLUSIONS

Analysis of the results indicated that DISE directed surgery was an effective, safe therapeutic approach to treating paediatrics obstructive sleep apnoea. DISE directed surgery has shown to have changed surgical management in most studies.

A Review of Sleep Disturbances among Infants and Children with Neurodevelopmental Disorders

Sleep problems are common among children with neurodevelopmental disorders (NDDs). We review sleep disturbance in three major NDDs: autism spectrum disorder, Down syndrome, and fetal alcohol spectrum disorder (FASD). We review associations with functional impairment, discuss how patterns of sleep disturbance inform understanding of etiology, and theorize about mechanisms of impairment. Sleep disturbance is a transdiagnostic feature of NDDs. Caregivers report high rates of sleep problems, including difficulty falling or staying asleep. Polysomnography data reveal differences in sleep architecture and increased rates of sleep disorders. Sleep disturbance is associated with functional impairment and stress among families. Further research is needed to elucidate mechanisms of impairment and develop more effective interventions. Despite significant sleep disturbance in FASD, limited research is available.

Obstructive Sleep Apnoea Contributes to Executive Function Impairment in Young Children with Down Syndrome

OBJECTIVE/BACKGROUND

Children with Down syndrome (DS) commonly experience difficulties with executive function (EF). They are also vulnerable to obstructive sleep apnoea (OSA). OSA is associated with EF deficits in typically developing children. A recent study reported an association between OSA and cognitive deficits in 38 school-aged children with DS. We experimentally investigated EF behaviours in young children with DS, and their association with OSA.

PARTICIPANTS AND METHODS

Children with DS were recruited to take part in a larger study of OSA (N = 202). Parents of 80 children (50 male) aged 36 to 71 months (M = 56.90, SD = 10.19 months) completed the Behavior Rating Inventory of Executive Function - Preschool Version (BRIEF-P). Of these 80 children, 69 were also successfully studied overnight with domiciliary cardiorespiratory polygraphy to diagnose OSA.

RESULTS

Obstructive apnoea/hypopnoea index was in the normal range (0-1.49/h) for 28 children but indicated OSA (≥1.5/h) in 41 children. Consistent with previous research, we found a large effect for children experiencing particular weaknesses in working memory, planning and organising, whilst emotional control was a relative strength. OSA was associated with poorer working memory (β = .23, R2 = .05, p = .025), emotional control (β = .20, R2 = .04, p = .047) and shifting (β = .24, R2 = .06, p = .023).

CONCLUSIONS

Findings suggest that known EF difficulties in DS are already evident at this young age. Children with DS already have limited cognitive reserve and can ill afford additional EF deficit associated with OSA. OSA is amenable to treatment and should be actively treated in these children to promote optimal cognitive development.

Sleep surgery in syndromic and neurologically impaired children

PURPOSE

To examine surgery performed for obstructive sleep apnea (OSA) in children with syndromic or neurologic comorbidities.

MATERIAL AND METHODS

Medical records of 375 children with OSA were retrospectively reviewed, including 142 patients with trisomy 21, 105 with cerebral palsy, 53 with muscular dystrophy, 32 with spinal muscular atrophy, 18 with mucopolysaccharidoses, 14 with achondroplasia, and 11 with Prader-Willi.

OUTCOME MEASURES

Apnea-hypopnea index (AHI), complications, length of postoperative stay, and endoscopic findings.

RESULTS

228 patients received 297 surgical interventions, with the remainder undergoing observation or positive pressure ventilation. Adenoidectomy was the most common procedure performed (92.1% of patients), followed by tonsillectomy (91.6%). Average AHI decreased following tonsillectomy, from 12.4 to 5.7 (p = 0.002). The most common DISE finding was the tongue base causing epiglottic retroflexion. Lingual tonsillectomy also resulted in an insignificant decrease in the AHI.

CONCLUSIONS

Adenotonsillectomy, when there is hypertrophy, remains the mainstay of management of syndromic and neurologically-impaired children with OSA. However, additional interventions are often required, due to incomplete resolution of the OSA. DISE is valuable in identifying remaining sites of obstruction and guiding future management.

Children with Down syndrome and mild OSA: treatment with medication versus observation

STUDY OBJECTIVES

Children with Down syndrome (DS) have a high prevalence of obstructive sleep apnea (OSA). Anti-inflammatory medications have been shown to be an effective treatment for mild OSA in otherwise healthy children. However, the efficacy in children with DS and mild OSA has not been investigated. Our aim was to examine the polysomnographic changes of children with DS and mild OSA treated with medication.

METHODS

A retrospective chart review was performed in children with DS (< 18 years) and mild OSA (obstructive apnea-hypopnea index ≤ 5 events/h) diagnosed by polysomnography (PSG) between 2006 and 2018. Patients were included if they were treated with medications (intranasal corticosteroids and/or montelukast) or by observation with a duration of at least 3 months and had baseline and follow-up PSGs. Demographic data, comorbid diagnoses, and PSG data were collected and analyzed.

RESULTS

Forty-five children met inclusion criteria. In the medication group, 29 children were identified. The median age was 7.4 years (interquartile range [IQR] 4.9-9.3). In the observation group, 16 children were identified. The median age was 4.0 years (IQR 3.2-5.3). The median time from baseline to follow-up PSG was 14.0 months (IQR 10.0-22.9) for the medication group and 10.5 months (IQR 6.5-33.5) for the observation group. There were no significant changes in the median obstructive apnea-hypopnea index from the baseline to follow-up PSG in either the medication group (2.8 [IQR 2.2-3.6) versus 3.5 [IQR 1.4-4.8) events/h; P = .25) or the observation group (2.3 [IQR 1.3-3.1] versus 2.9 [IQR 1.9-6.8] events/h; P = .12). Similarly, there were no significant differences in apnea-hypopnea index, oxygen nadir or end-tidal carbon dioxide between the groups (P = .07-1).

CONCLUSIONS

In our cohort, medication therapy did not significantly improve polysomnographic measures in children with DS and mild OSA. Several factors such as hypotonia and relative macroglossia may explain the ineffectiveness of medical therapy for OSA in this population. Further prospective studies are necessary to confirm these results and to evaluate if a subgroup of DS children may benefit from medical therapy.

The influence of sleep on language production modalities in preschool children with Down syndrome

Evidence suggests that sleep may relate to oral language production in children with Down syndrome. However, these children are capable of using complex referential gestures as a compensation strategy for problems with oral production, and those with a greater productive oral vocabulary have less gestural vocabulary. The goal of this study was to explore whether sleep quality relates to oral and gestural production modalities in children with Down syndrome. We evaluated 36 preschool children with and without Down syndrome, paired by chronological age and gender, with similar sociodemographic backgrounds, using actigraphy to measure sleep behaviour and the Communicative Development Inventory for Down syndrome to measure vocabulary. Children with Down syndrome with better sleep efficiency showed more oral production but less gestural production. These results highlight the importance of sleep quality to language learning in children with Down syndrome.

Obstructive sleep apnea in children with down syndrome - Prevalence and evaluation of surgical treatment

INTRODUCTION

The prevalence of obstructive sleep apnea (OSA) in the pediatric population with Down syndrome (DS) is reported to be 45-76%. The criterion "gold" standard for diagnosing OSA is polysomnography (PSG). First-hand surgical treatment is adenotonsillectomy (ATE), and another option is adenopharyngoplasty (APP). The aims of this study were to determine the OSA prevalence among children with DS who had undergone PSG and to evaluate and compare the efficiency and results of ATE and APP treatments.

METHODS AND MATERIALS

Children <18 years old with DS who underwent PSG at Karolinska University Hospital were included in this retrospective cohort study. Medical records were examined for patient age, sex, medical comorbidity diagnoses, and OSA treatment, and the results from PSG and the quality of life questionnaire OSA-18 were registered. The prevalence and degree of OSA were calculated. Results from a nonsystematic subgroup that underwent postoperative PSG and the OSA-18 were compiled to evaluate surgical efficiency. Pre- and postoperative results from APP and ATE patients were compared.

RESULTS

In the study, 138 DS children were included. The OSA prevalence was 82.6%, and 39.9% had severe OSA, with a median (range) apnea hypopnea index (AHI) of 7.6 (0-104). Other comorbidity diagnoses were found for ear disease in 60%, circulatory disease in 51% and endocrine disease in 39% of patients. A nonsystematic subgroup of 33 patients underwent postoperative PSG, with a residual prevalence of moderate or severe OSA of 63.6%. Among the ATE and APP patients with pre- and postoperative PSG (n = 20), no difference between the groups was shown, but the values were significantly improved as a whole: the median AHI changed from 21.1 to 12.4 and the median OSA-18 rating changed from 54.0 to 35.0.

CONCLUSIONS

In this population of children with DS, the OSA prevalence was over 80%, wherefore continued screening and treatment are strongly supported. Uncertain surgical efficiency was indicated, and no significant difference in the results for ATE and APP was shown. When interpreting the results, it should be taken into consideration that the frequency of postoperative PSG was low and nonsystematic and that the groups were unequal and small.

Altered sleep architecture, rapid eye movement sleep, and neural oscillation in a mouse model of human chromosome 16p11.2 microdeletion

Sleep abnormalities are common among children with neurodevelopmental disorders. The human chr16p11.2 microdeletion is associated with a range of neurological and neurobehavioral abnormalities. Previous studies of a mouse model of human chr16p11.2 microdeletion (chr16p11.2df/+) have demonstrated pathophysiological changes at the synapses in the hippocampus and striatum; however, the impact of this genetic abnormality on system level brain functions, such as sleep and neural oscillation, has not been adequately investigated. Here, we show that chr16p11.2df/+ mice have altered sleep architecture, with increased wake time and reduced time in rapid eye movement (REM) and non-REM (NREM) sleep. Importantly, several measurements of REM sleep are significantly changed in deletion mice. The REM bout number and the bout number ratio of REM to NREM are decreased in mutant mice, suggesting a deficit in REM-NREM transition. The average REM bout duration is shorter in mutant mice, indicating a defect in REM maintenance. In addition, whole-cell patch clamp recording of the ventrolateral periaqueductal gray (vlPAG)-projecting gamma-aminobutyric acid (GABA)ergic neurons in the lateral paragigantocellular nucleus of ventral medulla of mutant mice reveal that these neurons, which are important for NREM-REM transition and REM maintenance, have hyperpolarized resting membrane potential and increased membrane resistance. These changes in intrinsic membrane properties suggest that these projection-specific neurons of mutant mice are less excitable, and thereby may play a role in deficient NREM-REM transition and REM maintenance. Furthermore, mutant mice exhibit changes in neural oscillation involving multiple frequency classes in several vigilance states. The most significant alterations occur in the theta frequency during wake and REM sleep.

Down syndrome

Trisomy 21, the presence of a supernumerary chromosome 21, results in a collection of clinical features commonly known as Down syndrome (DS). DS is among the most genetically complex of the conditions that are compatible with human survival post-term, and the most frequent survivable autosomal aneuploidy. Mouse models of DS, involving trisomy of all or part of human chromosome 21 or orthologous mouse genomic regions, are providing valuable insights into the contribution of triplicated genes or groups of genes to the many clinical manifestations in DS. This endeavour is challenging, as there are >200 protein-coding genes on chromosome 21 and they can have direct and indirect effects on homeostasis in cells, tissues, organs and systems. Although this complexity poses formidable challenges to understanding the underlying molecular basis for each of the many clinical features of DS, it also provides opportunities for improving understanding of genetic mechanisms underlying the development and function of many cell types, tissues, organs and systems. Since the first description of trisomy 21, we have learned much about intellectual disability and genetic risk factors for congenital heart disease. The lower occurrence of solid tumours in individuals with DS supports the identification of chromosome 21 genes that protect against cancer when overexpressed. The universal occurrence of the histopathology of Alzheimer disease and the high prevalence of dementia in DS are providing insights into the pathology and treatment of Alzheimer disease. Clinical trials to ameliorate intellectual disability in DS signal a new era in which therapeutic interventions based on knowledge of the molecular pathophysiology of DS can now be explored; these efforts provide reasonable hope for the future.

Sleep disorders in children with Angelman and Smith-Magenis syndromes: The assessment of potential causes of disrupted settling and night time waking

BACKGROUND

Sleep problems are common in Smith-Magenis (SMS) and Angelman syndromes (AS). Effectiveness of interventions depends on appropriate assessment, complicated by compromised self-report and health and behaviour difficulties. Studying settling and waking in these syndromes could inform assessment.

AIMS

To describe settling and waking behaviours in children at high-risk of sleep and health problems, using direct observation.

METHODS AND PROCEDURES

Video and actigraphy data were collected for 12 participants with AS (Mean age = 8.02, SD = 2.81) and 11 with SMS (Mean age = 8.80, SD = 2.18). Settling (30 min prior to sleep onset) and night waking were coded for nineteen behaviours relating to pain, challenging behaviour and caregiver interaction. Lag sequential analyses were conducted for pain-related behaviours.

OUTCOMES AND RESULTS

Percentage of time spent in behaviours was calculated. Parent-child interactions (0.00-9.93 %) and challenging behaviours (0 %) were rare at settling and waking in both groups. In the AS group, pain-related behaviours were more likely to occur before waking than by chance (p < 0.001).

CONCLUSIONS AND IMPLICATIONS

Findings highlight the importance of considering pain as a cause of sleep problems in AS. The principle and methodology could be extended to individuals with ID experiencing sleep problems.

Sleep problems and recall memory in children with Down syndrome and typically developing controls

BACKGROUND

Research conducted with typically developing (TD) infants and children generally indicates that better habitual sleep and sleep after learning are related to enhanced memory. Less is known, however, about associations between sleep and recall memory in children with Down syndrome (DS).

AIMS

The present study was conducted to determine whether parent-reported sleep problems were differentially associated with encoding, 1-month delayed recall memory, and forgetting over time in children with DS and those who were TD.

METHODS AND PROCEDURES

Ten children with DS (mean age = 33 months, 5 days) and 10 TD children (mean age = 21 months, 6 days) participated in a two-session study. At each session, recall memory was assessed using an elicited imitation paradigm. Immediate imitation was permitted at the first session as an index of encoding, and delayed recall was assessed 1 month later. In addition, parents provided demographic information and reported on child sleep problems.

OUTCOMES AND RESULTS

Although parents did not report more frequent sleep problems for children with DS relative to TD children, regression-based moderation analyses revealed that more frequent sleep problems were associated with increased forgetting of individual target actions and their order by children with DS. Evidence of moderation was not found when examining encoding or delayed recall.

CONCLUSIONS AND IMPLICATIONS

Although group differences were not found when considering parent-reported sleep problems, more frequent sleep problems were positively associated with increased forgetting by children with DS relative to those who were TD. Although future experimental work is needed to determine causality, these results suggest that improved sleep in children with DS might reduce forgetting, ultimately improving long-term recall memory.

Sleep problems in Korean children with Down syndrome and parental quality of life

BACKGROUND

Sleep problems are common among children with Down syndrome (DS), and they can have a serious impact on children with DS as well as their parents and other family members. Specific aims of this study were to evaluate parent-reported sleep problems in children with DS and to examine the relationship between the sleep behaviour of children with DS and their parents' quality of life (QOL).

METHOD

A cross-sectional survey was conducted in September and October of 2017. Parents of children with DS were recruited from an online self-support community for parents of children with DS in South Korea. The mean age of the parents and children with DS was 40.40 years (SD = 5.09) and 7.89 years (SD = 3.03), respectively. Children's sleep problems and parents' QOL were assessed using the Children's Sleep Habits Questionnaire and the abbreviated version of the World Health Organization Quality of Life scale, respectively.

RESULTS

Results revealed that 83% of the parents reported that their child with DS experienced sleep problems. Children with DS had significantly more bedtime resistance, night waking, parasomnias and sleep-disordered breathing than did typically developing children. In addition, their Children's Sleep Habits Questionnaire scores were higher than those of typically developing children. Moreover, being older, being male and having more severe developmental delays were significant risk factors for sleep problems among children with DS. Furthermore, sleep problems in children with DS negatively affected parents' QOL.

CONCLUSIONS

Sleep problems negatively affect children with DS as well as their parents; therefore, health care providers should be aware of these issues and help parents manage sleep problems proactively.

An Ultra-miniaturized Near Infrared Spectroscopy System to Assess Sleep Apnea in Children with Down Syndrome

Down syndrome is one of the health disorders that interferes with regular and healthy sleep. Most children with Down syndrome are referred to a sleep clinic for the assessment of the severity of their apnea. Regular polysomnography based assessment of apnea has been challenging with this sensitive patient population. We present our efforts towards developing a flexible adhesive bandage sized near infrared spectroscopy system (pediBand) for home-assessment of apnea in children with Down syndrome. Combined with inertial measurement units, pediBand record heart rate, heart rate variability, respiratory rate, arterial oxygen saturation and cerebral oxygen saturation. These are the essential parameters to assess sleep apnea and could also potentially be used in the assessment of sleep performance in general. A modified version of pediBand system was evaluated on adult patients and successfully demonstrated the changes in hemodynamic system triggered by sleep apnea.

A Cross-Syndrome Comparison of Sleep-Dependent Learning on a Cognitive Procedural Task

Sleep plays a key role in the consolidation of newly acquired information and skills into long term memory. Children with Down syndrome (DS) and Williams syndrome (WS) frequently experience sleep problems, abnormal sleep architecture, and difficulties with learning; thus, we predicted that children from these clinical populations would demonstrate impairments in sleep-dependent memory consolidation relative to children with typical development (TD) on a cognitive procedural task: The Tower of Hanoi. Children with DS (n = 17), WS (n = 22) and TD (n = 34) completed the Tower of Hanoi task. They were trained on the task either in the morning or evening, then completed it again following counterbalanced retention intervals of daytime wake and night time sleep. Children with TD and with WS benefitted from sleep for enhanced memory consolidation and improved their performance on the task by reducing the number of moves taken to completion, and by making fewer rule violations. We did not find any large effects of sleep on learning in children with DS, suggesting that these children are not only delayed, but atypical in their learning strategies. Importantly, our findings have implications for educational strategies for all children, specifically considering circadian influences on new learning and the role of children's night time sleep as an aid to learning.

Does drug induced sleep endoscopy-directed surgery improve polysomnography measures in children with Down Syndrome and obstructive sleep apnea?

BACKGROUND

Children with Down Syndrome (DS) and obstructive sleep apnea (OSA) are difficult to treat, as first line therapies may not lead to significant improvement. Drug-induced sleep endoscopy (DISE) directed surgery may be particularly beneficial for these patients.

OBJECTIVE

To assess change in polysomnography (PSG) measures of patients with DS who underwent DISE-directed surgery.

METHODS

Retrospective chart review was performed on patients with DS who underwent DISE-directed surgery and had pre- and post-surgery PSG. Patients were analyzed in groups defined by previous adenotonsillectomy. Two-sided t-tests with equal variances were used to assess statistical significance.

RESULTS

Of 24 patients reviewed, 14 were surgically naïve and 10 had undergone prior adenotonsillectomy. The primary outcome was change in PSG parameters including apnea hypopnea index, obstructive apnea hypopnea index, oxygen nadir, oxygen desaturation index, and mean carbon dioxide level. While improvement was seen in all PSG parameters, only improvement in oxygen nadir in children who had undergone prior adenotonsillectomy was statistically significant (88.5% to 90.9%, p = .04).

CONCLUSIONS AND SIGNIFICANCE

DISE-directed surgery may be beneficial for children with DS and OSA, with improvement in the means of main PSG measures observed. A larger, prospective study is warranted to further explore DISE utility.

Small Sets of Novel Words Are Fully Retained After 1-Week in Typically Developing Children and Down Syndrome: A Fast Mapping Study

OBJECTIVES

Down syndrome (DS) is a population with known hippocampal impairment, with studies showing that individuals with DS display difficulties in spatial navigation and remembering arbitrary bindings. Recent research has also demonstrated the importance of the hippocampus for novel word-learning. Based on these data, we aimed to determine whether individuals with DS show deficits in learning new labels and if they may benefit from encoding conditions thought to be less reliant on hippocampal function (i.e., through fast mapping).

METHODS

In the current study, we examined immediate, 5-min, and 1-week delayed word-learning across two learning conditions (e.g., explicit encoding vs. fast mapping). These conditions were examined across groups (twenty-six 3- to 5-year-old typically developing children and twenty-six 11- to 28-year-old individuals with DS with comparable verbal and nonverbal scores on the Kaufman Brief Intelligence Test - second edition) and in reference to sleep quality.

RESULTS

Both individuals with and without DS showed retention after a 1-week delay, and the current study found no benefit of the fast mapping condition in either group contrary to our expectations. Eye tracking data showed that preferential eye movements to target words were not present immediately but emerged after 1-week in both groups. Furthermore, sleep measures collected via actigraphy did not relate to retention in either group.

CONCLUSIONS

This study presents novel data on long-term knowledge retention in reference to sleep patterns in DS and adds to a body of knowledge helping us to understand the processes of word-learning in typical and atypically developing populations. (JINS, 2018, 24, 955-965).

Sleep-disordered breathing in paediatric setting: existing and upcoming of the genetic disorders

Childhood obstructive sleep apnea syndrome (OSAS) is characterized by anatomical and functional upper airway abnormalities as pathophysiological determinants, and clinical symptoms are frequently clear. OSAS is widely described in rare genetic disorders, such as achondroplasia, Down syndrome, Prader-Willi syndrome, Pierre Robin sequence, and mucopolysaccharidosis. Craniofacial and upper airway involvement is frequently morbid conditions. In children with genetic diseases, the clinical symptoms of OSAS are often slight or absent, and related morbidities are usually more severe and can be observed at any age. The present review is aimed to updating the discoveries regarding OSAS on Achondroplasia, Down syndrome, Prader-Willi syndrome, Pierre Robin sequence, Sickle cell disease, or encountered in our clinical practice (Ehlers-Danlos syndrome, Ellis-van Creveld syndrome, Noonan syndrome). Two additional groups of genetic disorders will be focused (mucopolysaccharidoses and osteogenesis imperfecta). The flowing items are covered for each disease: (I) what is the pathophysiology of OSAS? (II) What is the incidence/prevalence of OSAS? (III) What result from the management and prognosis? (IV) What are the recommendations? Considering the worries of OSAS, such as inattention and behavioural problems, daytime sleepiness, failure to thrive, cardiological and metabolic complications, the benefit of a widespread screening and the treatment in children with genetic diseases is undoubtful. The goals of the further efforts can be the inclusion of various genetic diseases into guidelines for the screening of OSAS, updating the shreds of evidence based on the research progression.

Obstructive Sleep Apnea in Children with Down Syndrome: Demographic, Clinical, and Polysomnographic Features

Objectives

To evaluate demographic, clinical, and polysomnographic features of children with Down syndrome suspected of having obstructive sleep apnea. To identify factors that predict severe obstructive sleep apnea among children with Down syndrome.

Study Design

Case series with chart review.

Setting

Children’s Medical Center Dallas / University of Texas Southwestern Medical Center.

Subject and Methods

Demographic, clinical, and polysomnographic data were collected for children with Down syndrome aged 2 to 18 years. Simple and multivariable regression models were used to study predictors of severe obstructive sleep apnea (apnea-hypopnea index ≥10). P≤ .05 was considered significant.

Results

A total of 106 children with Down syndrome were included, with 89 (84%) <12 years old, 56 (53%) male, 72 (68%) Hispanic, 15 (14%) African American, and 14 (13%) Caucasian. Ninety percent of children had ≥1 medical comorbidities; 95 (90%) patients had obstructive sleep apnea; and 46 (44%) had severe obstructive sleep apnea. The mean SaO2 nadir was lower among obese than nonobese children (80% vs 85%, P = .02). Obese versus nonobese patients had a higher prevalence of severe obstructive sleep apnea (56% vs 35%, P = .03). Severe OSA was associated with heavier weight (odds ratio = 1.0, 95% CI: 1.0-1.1, P = .002) and age ≥12 years (odds ratio = 1.2, 95% CI: 0.2-2.5, P = .02). The multivariable model showed that severe obstructive sleep apnea was associated only with weight (odds ratio = 1.1, 95% CI: 1.0-1.1, P = .02).

Conclusion

Obese children with DS are at a high risk for severe OSA, with weight as the sole risk factor. The results of this study show the importance of monitoring the weight of children with DS and counseling parents of children with DS about weight loss.

Sleep-Disordered Breathing

PURPOSE OF REVIEW

Sleep-disordered breathing encompasses a broad spectrum of sleep-related breathing disorders, including obstructive sleep apnea (OSA), central sleep apnea, as well as sleep-related hypoventilation and hypoxemia. Diagnostic criteria have been updated in the International Classification of Sleep Disorders, Third Edition and the American Academy of Sleep Medicine Manual for Scoring Sleep and Associated Events. Neurologic providers should have basic knowledge and skills to identify at-risk patients, as these disorders are associated with substantial morbidity, the treatment of which is largely reversible.

RECENT FINDINGS

OSA is the most common form of sleep-disordered breathing and is highly prevalent and grossly underdiagnosed. Recent studies suggest that prevalence rates in patients with neurologic disorders including epilepsy and stroke exceed general population estimates. The physiologic changes that occur in OSA are vast and involve complex mechanisms that play a role in the pathogenesis of cardiovascular and metabolic disorders and, although largely unproven, likely impact brain health and disease progression in neurologic patients. A tailored sleep history and examination as well as validated screening instruments are effective in identifying patients with sleep-disordered breathing, although sleep testing is necessary for diagnostic confirmation. While continuous positive airway pressure therapy and other forms of noninvasive positive pressure ventilation remain gold standard treatments, newer therapies, including mandibular advancement, oral appliance devices, and hypoglossal nerve stimulation, have become available. Emerging evidence of the beneficial effects of treatment of sleep-disordered breathing on neurologic outcomes underscores the importance of sleep education and awareness for neurologic providers.

SUMMARY

Sleep-disordered breathing is highly prevalent and grossly underrecognized. The adverse medical and psychosocial consequences of OSA and other sleep-related breathing disorders are considerable. The impact of sleep therapies on highly prevalent neurologic disorders associated with substantial morbidity and health care costs is becoming increasingly recognized.

Prevalence of Obstructive Sleep Apnea in Children With Down Syndrome: A Meta-Analysis

STUDY OBJECTIVES

To estimate the prevalence of obstructive sleep apnea (OSA) in children with Down syndrome.

METHODS

Two authors independently searched databases, namely PubMed, MEDLINE, EMBASE, and the Cochrane Review database. The keywords used were "Down syndrome," "Trisomy 21," "OSA," "sleep apnea syndromes," "polysomnography" and "polygraphy." The prevalence of OSA based on apnea-hypopnea index (AHI) greater than 1, 1.5, 2, 5, and 10 event/h was estimated using a random-effects model. Subgroup analyses were conducted for children in different countries, sample size, study year, and risk of bias. Finally, the prevalence of OSA was compared between two types of sleep studies (polysomnography versus polygraphy).

RESULTS

A total of 18 studies (1,200 children) were included (mean age: 7.7 years; 56% boys; mean sample size: 67 patients). Five studies had low risk of bias, and nine and four studies had moderate and high risk of bias, respectively. The OSA was evaluated through polygraphy in 2 studies, and polysomnography in 16 studies. For children who underwent polysomnography, the prevalences of OSA based on AHI > 1, 1.5, 2, 5, and 10 events/h were 69%, 76%, 75%, 50%, and 34%, respectively. Subgroup analyses revealed no significant difference among all subgroups. Meta-regression showed that AHI > 5 events/h was inversely correlated with age (P < .001). Moreover, the prevalence of OSA based on AHI > 1.5 events/h was lower in polygraphy compared with polysomnography (59% versus 76%, P = .037).

CONCLUSIONS

OSA is highly prevalent in children with Down syndrome. Prevalence of moderate to severe OSA is higher in younger age.

The Role of Functional Respiratory Imaging in Treatment Selection of Children With Obstructive Sleep Apnea and Down Syndrome

STUDY OBJECTIVES

The complexity of the pathogenesis of obstructive sleep apnea (OSA) in children with Down syndrome (DS) is illustrated by a prevalence of residual OSA after adenotonsillectomy. The aim of this study was to investigate whether upper airway imaging combined with computation fluid dynamics could characterize treatment outcome after adenotonsillectomy in these children.

METHODS

Children with DS and OSA were prospectively included. All children underwent an evaluation of the upper airway and an ultra-low dose computed tomography scan of the upper airway before adenotonsillectomy. The upper airway tract was extracted from the scan and combined with computational fluid dynamics. Results were evaluated using control polysomnography after adenotonsillectomy.

RESULTS

Thirty-three children were included: 18 boys, age 4.3 ± 2.3 years, median body mass index z-score 0.6 (-2.9 to 3.0), and median obstructive apnea-hypopnea index was 15.7 (3-70) events/h. The minimal upper airway cross-sectional area was significantly smaller in children with more severe OSA (P = .03). Nineteen children underwent a second polysomnography after adenotonsillectomy. Seventy-nine percent had persistent OSA (obstructive apneahypopnea index > 2 events/h). A greater than 50% decrease in obstructive apnea-hypopnea index was observed in 79% and these children had a significantly higher volume of the regions below the tonsils.

CONCLUSIONS

This is the first study to characterize treatment outcome in children with DS and OSA using computed tomography upper airway imaging. At baseline, children with more severe OSA had a smaller upper airway. Children with a less favorable response to adenotonsillectomy had a smaller volume of regions below the tonsils, which could be due to enlargement of the lingual tonsils, glossoptosis, or macroglossia.

COMMENTARY

A commentary on this article appears in this issue on page 501.

Sleep Behavior and EEG Oscillations in Aged Dp(16)1Yey/+ Mice: A Down Syndrome Model

Down syndrome (DS) results from the triplication of genes located on human chromosome 21 (Hsa21). Though many cognitive and behavioral impairments are associated with DS, sleep disturbances remain poorly understood despite being a reported phenotype in approximately 60% of individuals diagnosed with DS. In this study, sleep and electroencephalography (EEG) oscillations were recorded from aged (12–14 mos.) Dp(16)1Yey/+ mice (Dp16), a mouse model of DS. We observed disrupted sleep demonstrated by increased activity during the dark phase and increased time awake at the expense of NREM sleep compared to wild-type mice. In addition, we found that Dp16 mice display significant differences in relative EEG power distribution among oscillation frequencies in both sleep and awake states. These results in Dp16 mice are consistent with sleep disturbances found in individuals with DS, and the abnormal EEG oscillations in aged Dp16 mice suggest a potential role for GABAergic activity in these sleep and EEG abnormalities. These sleep and EEG data reflect underlying differences in neuronal activity at the network level and thus are causative agents rather than merely symptoms of DS.

Co-occurring medical conditions in adults with Down syndrome: A systematic review toward the development of health care guidelines

Adults with Down syndrome (DS) represent a unique population who are in need of clinical guidelines to address their medical care. The United States Preventive Service Task Force (USPSTF) has developed criteria for prioritizing conditions of public health importance with the potential for providing screening recommendations to improve clinical care. The quality of existing evidence needed to inform clinical guidelines has not been previously reviewed. Using the National Library of Medicine (NLM) database PubMed, we first identified 18 peer reviewed articles that addressed co-occurring medical conditions in adults with DS. Those conditions discussed in over half of the articles were prioritized for further review. Second, we performed detailed literature searches on these specific conditions. To inform the search strategy and review process a series of key questions were formulated a priori. The quality of available evidence was then graded and knowledge gaps were identified. The number of participating adults and the design of clinical studies varied by condition and were often inadequate for answering all of our key questions. We provide data on thyroid disease, cervical spine disease, hearing impairment, overweight-obesity, sleep apnea, congenital heart disease, and osteopenia-osteoporosis. Minimal evidence demonstrates massive gaps in our clinical knowledge that compromises clinical decision-making and management of these medically complex individuals. The development of evidence-based clinical guidance will require an expanded clinical knowledge-base in order to move forward.

Sobrecarga dos cuidadores de crianças e adolescentes com Síndrome de Down

Resumo O objetivo foi avaliar o perfil e a sobrecarga de cuidadores de crianças/adolescentes com e sem síndrome de Down. As avaliações foram realizadas por meio dos questionários sobre o perfil e a sobrecarga dos cuidadores (Burden Interview), e o perfil das crianças/adolescentes. Estes questionários foram aplicados a 168 cuidadores. Os testes Qui-quadrado, Exato de Fisher e Análise de Variância foram empregados com nível de significância fixado em α = 5%. Ambos os grupos eram compostos por 84 participantes, e os cuidadores do grupo com deficiência apresentaram porcentagem significantemente maior para o sexo feminino (p = 0,001), faixa etária de 41-60 anos (p < 0,001), não possuíam ocupação laboral (p < 0,001), baixa renda per capita (p < 0,001), baixo nível de escolaridade (p = 0,021), religião católica (p = 0,001), maiores de problemas de saúde (p < 0,001), em uso de medicação continua (p < 0,001) e com nível de sobrecarga moderada (p < 0,001). As crianças/adolescentes com deficiência necessitavam significantemente maior auxilio para a alimentação (p = 0,051), banho (p = 0,006), vestuário (p = 0,042), controle de esfíncteres (p = 0,027) e higiene íntima (p < 0,001). Os cuidadores de crianças/adolescentes com síndrome de Down apresentam sobrecarga moderada, quando comparados à cuidadores de crianças/adolescentes normoreativas.

Sleep-disordered breathing and cognitive functioning in preschool children with and without Down syndrome

BACKGROUND

Sleep affects children's cognitive development, preparedness for school and future academic outcomes. People with Down syndrome (DS) are particularly at risk for sleep-disordered breathing (SDB). To our knowledge, the association between SDB and cognition in preschoolers with DS is unknown.

METHODS

We assessed sleep by using cardiorespiratory polygraphy in 22 typically developing (TD) preschoolers and 22 with DS. Cognition was assessed by using the Mullen Scales of Early Learning and behaviour by using the Strengths and Difficulties Questionnaire (SDQ). The MacArthur Communicative Development Inventory (MCDI) measured language level. We predicted that sleep problems would be associated with lower cognitive and behavioural functioning.

RESULTS

In TD children, longer sleep duration was associated with higher scores on MCDI expressive language and fewer emotional symptoms such as fear and unhappiness on the SDQ, whilst SDB was associated with increased conduct problems and less prosocial behaviour on the SDQ. Conversely, for children with DS, SDB was associated with increased language understanding and use of actions and gestures on the MCDI.

CONCLUSIONS

The findings in the TD group support our hypotheses. We recommend that sleep problems are screened for and treated as even mild SDB may prompt poorer cognition and behaviour. For children with DS, we expect that multiple factors in this complex syndrome mask or mediate the association between sleep and cognitive development and tighter controls are necessary to uncover effects of sleep. We propose longitudinal studies as a necessary tool to assess the precise impact of sleep on cognitive development in accounting for individual differences in DS.

Tonsillectomy in Children with Down Syndrome: A National Cohort of Inpatients

Objective To describe the cost, length of stay, and incidence of postoperative hemorrhage associated with Down syndrome (DS) patients undergoing tonsillectomy in a national sample of inpatient children. Study Design This study uses a national cross-sectional cohort to analyze children with and without DS undergoing tonsillectomy with or without adenoidectomy. Setting 2012 Healthcare Cost and Utilization Project Kids' Inpatient Database. Subjects and Methods The database was analyzed for postoperative hemorrhage and respiratory compromise, length of stay, and total charges of hospital stay. These outcomes were compared between patients with DS vs patients without DS. Results In total, 7512 patients were identified who underwent tonsillectomy: 7159 patients without DS and 353 patients with DS. The non-DS group was younger with a median age of 3 years (range, 0-18) compared with a DS median age of 4 years (range, 0-20), P = .004. The DS group had a significant increase in postoperative hemorrhage compared with non-DS (10 [2.8%] vs 87 [1.2%], respectively), P = .024. However, the DS and non-DS groups were comparable for respiratory complications (5 [1.4%] vs 106 [1.5%], respectively), P = .922. Median length of stay was significantly increased in the DS group (1 [interquartile range (IQR), 1-3]) compared with the non-DS group (1 [IQR, 1-2]), P < .001. Median charges for hospital stay totaled $17,451 (IQR, $11,901-$24,949) for the DS group compared with $14,395 (IQR, $9739-$21,890) for the non-DS group, P < .001. Conclusion Across the United States, children with DS hospitalized for tonsillectomy have an increased length of stay and cost of care. These data also suggest an increased risk of postoperative hemorrhage during the initial admission without an increased risk of respiratory complications.

Sleep Apnea and Hypoventilation in Patients with Down Syndrome: Analysis of 144 Polysomnogram Studies

Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central sleep apnea (CSA); however, it is unclear how these components evolve as patients age and whether patients are also at risk for hypoventilation. A retrospective review of 144 diagnostic polysomnograms (PSG) in a tertiary care facility over 10 years was conducted. Descriptive data and exploratory correlation analyses were performed. Sleep disordered breathing was common (seen in 78% of patients) with an average apnea-hypopnea index (AHI) = 10. The relative amount of obstructive apnea was positively correlated with age and body mass index (BMI). The relative amount of central sleep apnea was associated with younger age in the very youngest group (0–3 years). Hypoventilation was common occurring in more than 22% of patients and there was a positive correlation between the maximum CO₂ and BMI. Sleep disordered breathing, including hypoventilation, was common in patients with DS. The obstructive component increased significantly with age and BMI, while the central component occurred most in the very young age group. Due to the high risk of hypoventilation, which has not been previously highlighted, it may be helpful to consider therapies to target both apnea and hypoventilation in this population.

Obstructive Sleep Apnea and Pulmonary Hypertension in Children

Obstructive sleep apnea (OSA) is a common pediatric breathing disorder, affecting 1-5% of all children. Pulmonary hypertension (PH), a severe complication of OSA, is associated with significant morbidity and mortality. Despite this important relationship between OSA and PH, there is sparse literature addressing this subject in children. This review will examine the putative relationship between OSA and PH, synthesize the available literature in children, and suggest a reasonable approach, despite limited data, for clinicians. We conclude that available evidence suggests many children with OSA have evidence of PH (estimates ranging from 0% to 85%) and vice versa (estimates ranging from 6% to 24%). Furthermore, previous studies demonstrate that treatment of the OSA, either with surgery or non-invasive ventilation, ameliorates pulmonary artery pressures to the extent of cure in a substantial number of cases. Future studies are required to better delineate the true co-occurrence of these diseases and help predict which patients are at greater risk for this serious complication. Clinicians who maintain a healthy vigilance for this important interaction of disease states will likely recognize opportunities to intervene and improve prognoses in these patients.

Sleep problems and temperament in young children with Down syndrome and typically developing controls

BACKGROUND

Although group differences have been found between children with Down syndrome (DS) and typically developing (TD) children when considering sleep problems and temperament independently, none of the research conducted to date has examined sleep-temperament associations in children with DS. The present research was conducted to determine (1) whether the sleep problems experienced by children with DS are associated with temperament or (2) if the demonstrated relations between sleep and temperament differ from those that are observed in TD children.

METHOD

The present study included examination of relations between parent-reported sleep problems and temperament in 19 children with DS and 20 TD controls matched on developmental age.

RESULTS

The results revealed group differences in temperament and sleep problems. Mediation models indicated that temperament (effortful control and inhibitory control) mediated the association between group and sleep problems; sleep problems also mediated the association between group and temperament (effortful and inhibitory control).

CONCLUSION

Findings indicated that sleep problems may serve as both cause and consequence of variability in effortful and inhibitory control and provide insight as to future experimental studies that should be conducted to better elucidate these relations.