Karen Spruyt

Adenotonsillectomy outcomes in treatment of obstructive sleep apnea in children: a multicenter retrospective study.

RATIONALE The overall efficacy of adenotonsillectomy (AT) in treatment of obstructive sleep apnea syndrome (OSAS) in children is unknown. Although success rates are likely lower than previously estimated, factors that promote incomplete resolution of OSAS after AT remain undefined. OBJECTIVES To quantify the effect of demographic and clinical confounders known to impact the success of AT in treating OSAS. METHODS A multicenter collaborative retrospective review of all nocturnal polysomnograms performed both preoperatively and postoperatively on otherwise healthy children undergoing AT for the diagnosis of OSAS was conducted at six pediatric sleep centers in the United States and two in Europe. Multivariate generalized linear modeling was used to assess contributions of specific demographic factors on the post-AT obstructive apnea-hypopnea index (AHI). MEASUREMENTS AND MAIN RESULTS Data from 578 children (mean age, 6.9 +/- 3.8 yr) were analyzed, of which approximately 50% of included children were obese. AT resulted in a significant AHI reduction from 18.2 +/- 21.4 to 4.1 +/- 6.4/hour total sleep time (P < 0.001). Of the 578 children, only 157 (27.2%) had complete resolution of OSAS (i.e., post-AT AHI <1/h total sleep time). Age and body mass index z-score emerged as the two principal factors contributing to post-AT AHI (P < 0.001), with modest contributions by the presence of asthma and magnitude of pre-AT AHI (P < 0.05) among nonobese children. CONCLUSIONS AT leads to significant improvements in indices of sleep-disordered breathing in children. However, residual disease is present in a large proportion of children after AT, particularly among older (>7 yr) or obese children. In addition, the presence of severe OSAS in nonobese children or of chronic asthma warrants post-AT nocturnal polysomnography, in view of the higher risk for residual OSAS.

Pediatric sleep questionnaires as diagnostic or epidemiological tools: A review of currently available instruments

An extensive list of published and unpublished instruments used to investigate or evaluate sleep issues in children was collected and assessed based on the fundamental operational principles of instrument development (11 steps). Of all the available tools identified, only a few were validated and standardized using appropriate psychometric criteria. In fact, only 2 fulfill all desirable criteria and approximately 11 instruments seem to adhere to most of the psychometric tool development requirements, and were therefore assessed in greater detail. Notwithstanding, in the rapidly developing scientific world of pediatric sleep, there are too many tools being used that have not undergone careful and methodical psychometric evaluation, and as such may be fraught with biased or invalid findings. It is hoped that this initial effort in categorizing and assessing available tools for pediatric sleep will serve as recognition of the relatively early developmental stage of our field, and provide the necessary impetus for future tool development using multicentered approaches and adequate methodologies.

Sleep Duration, Sleep Regularity, Body Weight, and Metabolic Homeostasis in School-aged Children

OBJECTIVE: The goal was to explore the effects of duration and regularity of sleep schedules on BMI and the impact on metabolic regulation in children. METHODS: Sleep patterns of 308 community-recruited children 4 to 10 years of age were assessed with wrist actigraphs for 1 week in a cross-sectional study, along with BMI assessment. Fasting morning plasma levels of glucose, insulin, lipids, and high-sensitivity C-reactive protein also were measured for a subsample. RESULTS: Children slept 8 hours per night, on average, regardless of their weight categorization. A nonlinear trend between sleep and weight emerged. For obese children, sleep duration was shorter and showed more variability on weekends, compared with school days. For overweight children, a mixed sleep pattern emerged. The presence of high variance in sleep duration or short sleep duration was more likely associated with altered insulin, low-density lipoprotein, and high-sensitivity C-reactive protein plasma levels. Children whose sleep patterns were at the lower end of sleep duration, particularly in the presence of irregular sleep schedules, exhibited the greatest health risk. CONCLUSIONS: Obese children were less likely to experience “catch-up” sleep on weekends, and the combination of shorter sleep duration and more-variable sleep patterns was associated with adverse metabolic outcomes. Educational campaigns, aimed at families, regarding longer and more-regular sleep may promote decreases in obesity rates and may improve metabolic dysfunction trends in school-aged children.

Odds, prevalence and predictors of sleep problems in school-age normal children.

The objectives of the study were to describe the prevalence, odds, and predictors of 36 paediatric sleep behaviours and describe their coexistence in a school‐age normal population. The design was community‐based questionnaire survey of sleep–wake patterns, sleep environment, and 36 sleep behaviours indicative of six sleep disorder‐subscales using the Health‐Behaviour Questionnaire. A caregivers’ report of 3045 children aged 6–13 years in Belgium constituted the participants. Prevalence of each sleep behaviour was calculated. Log‐linear modelling within and between the sleep disorder‐subscales was used to screen for coexistence. The effect size of selected night‐time parameters to the likelihood of sleep behaviours and disorder‐subscale was expressed as odds ratios via logit regression analysis. Significant differences in sleep–wake patterns were found between weekday and weekend. Ranking by odds showed that: (1) sleep problems such as ‘tired when waking up’, ’repetitive limb movements’, ‘going to bed reluctantly’, and ‘sleep paralysis’ and; (2) the disorder‐subscale ‘excessive somnolence’ are common in children. Coexistences within and between disorder‐subscales of sleep problems are evident in a school‐age, normal population. These results suggest that disorders of excessive somnolence (DES) are highly prevalent in a non‐clinical sample of school‐age children. Furthermore, sleep‐onset latency and a noisy, not well‐darkened room are predictive towards the odds for exhibiting sleep problems and disorders. It is advocated that more information on the importance of good sleep–wake hygiene should reach parents and children.

Neurocognitive and Endothelial Dysfunction in Children With Obstructive Sleep Apnea

OBJECTIVE: Pediatric obstructive sleep apnea syndrome (OSAS) is associated with neurocognitive and endothelial dysfunction. However, it is unclear whether these 2 frequent morbidities of OSAS in children represent similar or different underlying pathophysiological processes, because they have never been concurrently assessed in children. METHODS: Consecutive children (ages 5–8 years) with polysomnographically based OSAS underwent cognitive battery evaluation (Differential Ability Scales and the NeuroPsychological Assessment Battery) and cuff-occlusion hyperemic tests for assessment of endothelial function. The presence of neurocognitive deficits (NC+) was defined on the basis of the presence of ≥2 abnormal cognitive test results. Endothelial dysfunction (ED+) was defined as a time to maximal postocclusive hyperemic response of ≥45 seconds (Tmax). RESULTS: Twenty-one control children and 87 children with OSAS completed both cognitive and endothelial tests. Of these children, 48 were NC+ and 50 had a Tmax of ≥45 seconds, and at least 80% of these children were in both groups. Conversely, among children in whom there was no presence of neurocognitive deficits (NC−), only 25.6% were ED+, whereas among those without endothelial dysfunction (ED−) only 21.6% were NC+. Furthermore, approximately one-third of the children with OSAS was NC− and ED−. Thus, findings on hyperemic vascular responses were highly predictive of neurocognitive status. CONCLUSIONS: Endothelial dysfunction and neurocognitive deficits are more likely to coexist than otherwise predicted from the frequency of each of these morbidities alone in pediatric OSAS. Thus, both of these morbid consequences may share similar pathogenetic mechanisms. Furthermore, a simple test such as the postocclusive hyperemic vascular response may help detect at-risk patients for neuropsychological deficits.

Sleep disturbances in children with attention-deficit/hyperactivity disorder

In this article, we advocate the need for better understanding and treatment of children exhibiting inattentive, hyperactive, impulsive behaviors, by in-depth questioning on sleepiness, sleep-disordered breathing or problematic behaviors at bedtime, during the night and upon awakening, as well as night-to-night sleep duration variability. The relationships between sleep and attention-deficit/hyperactivity disorder (ADHD) are complex and are routinely overlooked by practitioners. Motricity and somnolence, the most consistent complaints and objectively measured sleep problems in children with ADHD, may develop as a consequence of multidirectional and multifactorial pathways. Therefore, subjectively perceived or reported restless sleep should be evaluated with specific attention to restless legs syndrome or periodic limb movement disorder, and awakenings should be queried with regard to parasomnias, dyssomnias and sleep-disordered breathing. Sleep hygiene logs detailing sleep onset and offset quantitatively, as well as qualitatively, are required. More studies in children with ADHD are needed to reveal the 24-h phenotype, or its sleep comorbidities.

Development of pediatric sleep questionnaires as diagnostic or epidemiological tools: A brief review of Dos and Don'ts

Questionnaires are a useful and extensively used tool in clinical sleep medicine and in sleep research. The number of sleep questionnaires targeting the pediatric age range has tremendously increased in recent years, and with such explosion in the number of instruments, their heterogeneity has become all the more apparent. Here, we explore the theoretical and pragmatic processes required for instrument design and development, i.e., how any questionnaire, inventory, log, or diary should be created and evaluated, and also provide illustrative examples to further underline the potential pitfalls that are inherently embedded in every step of tool development.

Screening of Pediatric Sleep-Disordered Breathing: A Proposed Unbiased Discriminative Set of Questions Using Clinical Severity Scales

BACKGROUND Identification of sleep-disordered breathing (SDB) using questionnaires is critical from a clinical and research perspective. However, which questions to use and how well such questionnaires perform has thus far been fraught with substantial uncertainty. We aimed at delineating the usefulness of a set of questions for identifying pediatric SDB. METHODS Random prospective sampling of urban 5- to 9-year-old children from the community and enriched for habitual snoring underwent overnight sleep study. Subjective indicators or questions were evaluated to further characterize and discriminate SDB. RESULTS Of 1,133 subjects, 52.8% were habitual snorers. This sample was analyzed based on a clinical grouping (ie, established apnea-hypopnea index cutoffs). Several statistical steps were performed and indicated that complaints can be ranked according to a severity hierarchy: shake child to breathe, apnea during sleep, struggle breathing when asleep, and breathing concerns while asleep, followed by loudness of snoring and snoring while asleep. With a posteriori cutoff, a predictive score > 2.72 on the severity scale was found (ie, area under the curve, 0.79 ± 0.03; sensitivity, 59.03%; specificity, 82.85%; positive predictive value, 35.4; negative predictive value, 92.7), making this cutoff applicable for confirmatory purposes. CONCLUSIONS As a result, the set of six hierarchically arranged questions will aid the screening of children at high risk for SDB but cannot be used as the sole diagnostic approach.

Sleep Assessments In Healthy School-Aged Children Using Actigraphy: Concordance with Polysomnography

Actigraphic (ACT) recordings are used widely in schoolchildren as a less intrusive and more extended approach to evaluation of sleep problems. However, critical assessment of the validity and reliability of ACT against overnight polysomnography (NPSG) are unavailable. Thus, we explored the degree of concordance between NPSG and ACT in school‐aged children to delineate potential ACT boundaries when interpreting pediatric sleep. Non‐dominant wrist ACT was recorded simultaneously with NPSG in 149 healthy school‐aged children (aged 4.1–8.8 years, 41.7% boys, 80.4% Caucasian) recruited from the community. Analyses were limited to the Actiware (MiniMitter‐64) calculated parameters originating from 1‐min epoch sampling and medium sensitivity threshold value of 40; i.e. sleep period time (SPT), total sleep time (TST) and wake after sleep onset (WASO). SPT was not significantly different between ACT and NPSG. However, ACT underestimated TST significantly by 32.2 ± 33.4 min and overestimated WASO by 26.3 ± 34.4 min. The decreased precision of ACT was also evident from moderate to small concordance correlation coefficients (0.47 for TST and 0.09 for WASO). ACT in school‐aged children provides reliable assessment of sleep quantity, but is relatively inaccurate during determination of sleep quality. Thus, caution is advocated in drawing definitive conclusions from ACT during evaluation of the sleep‐disturbed child.

Fatty-acid binding protein 4 gene polymorphisms and plasma levels in children with obstructive sleep apnea

INTRODUCTION Obstructive sleep apnea (OSA) is associated with increased risk for metabolic syndrome in both adults and children. In adults with OSA, serum levels of fatty acid binding protein 4 (FABP4) are elevated and associated with the degree of metabolic insulin resistance, independent of obesity. Therefore, we assessed plasma FABP4 levels and FABP4 allelic variants in obese and non-obese children with and without OSA. METHODS A total of 309 consecutive children ages 5-8years were recruited. Children were divided into those with OSA and without OSA (NOSA) based on the apnea-hypopnea index (AHI). Subjects were also subdivided into obese (OB) and non-obese (NOB) based on BMI z score. Morning fasting plasma FABP4 levels were assayed using ELISA, and 11 single-nucleotide polymorphisms (SNPs) within the FABP4 region were genotyped. RESULTS Morning plasma FABP4 levels were increased in all children with OSA, even in NOB children. However, plasma FABP4 levels were strongly associated with BMI z score. Of the 11 SNPs tested, the frequency of rs1054135 (A/G) minor allele (A) was significantly increased in OSA. This SNP was also associated with increased plasma FABP4 levels in both OSA and obese subjects. The minor allele frequency of all other SNPs was similar in OSA and NOSA groups. CONCLUSIONS Childhood obesity and OSA are associated with higher plasma FABP4 levels and thus promote cardiometabolic risk. The presence of selective SNP (e.g., rs1054135) in the FABP4 gene may account for increased plasma FABP4 levels in the context of obesity and OSA in children.