Sleep disordered breathing in medically stable patients with myasthenia gravis

We investigate sleep and breathing in clinically stable myasthenia gravis (MG) patients and ask weather sleep disordered breathing (SDB) is causally linked with MG. Nineteen MG patients with a mean disease duration of 9.7 years underwent sleep studies in two consecutive nights. The primary outcome measure was the respiratory disturbance index (RDI) in terms of snoring and apneas/hypopneas. Further outcome measurements were total sleep time, sleep stage distribution and the number of arousals. A clinically relevant SDB in terms of obstructive sleep apnea (OSA) (defined as RDI > 10/h) was found in four patients. There were only a few central apneas (central apnea index: 0.19 ± 0.4/h). We did not find a relationship between maximum inspiratory pressure and SDB ( r  = −0.03). There is no evidence for a causal relationship between medically stable MG and SDB in terms of OSA. The extent of respiratory muscle weakness failed to correlate with SDB. Furthermore, our study does not confirm the high occurrence of central respiratory events during sleep in patients with well-controlled MG.     

Sleep-disordered breathing does not affect nocturnal dipping,as assessed by pulse transit time,in preschool children: evidence for early intervention to prevent adverse cardiovascular effects?

ObjectiveSleep-disordered breathing (SDB) is associated with reduced nocturnal dipping of blood pressure (BP) and sleep disruption in adults, and these features confer an increased risk of cardiovascular events. As SDB prevalence in children peaks during the preschool years, we investigated nocturnal dipping and sleep fragmentation in preschool children with SDB.MethodsChildren (3–5 years; n = 163) grouped by obstructive apnoea hypopnoea index (OAHI): control, no snoring history and OAHI ⩽1 event/h; primary snoring, OAHI ⩽1 event/h; mild SDB, >1–⩽5 events/h; moderate–severe SDB, >5 events/h. Pulse transit time (PTT), an inverse continuous indicator of BP changes, and heart rate (HR) during total sleep time and the first period of rapid eye movement (REM), non-REM (NREM)1/2 and NREM3/4 sleep were expressed as percentage change from wake before sleep onset. The sleep fragmentation index (SFI) was calculated as the number of sleep stage transitions or awakenings per hour of sleep.ResultsThere were no group differences in the change in PTT or HR from wake to total sleep time or to individual sleep stages or in the proportion of children in the quartile with the smallest change in PTT during total sleep. Children with moderate–severe SDB had higher SFI than primary snoring (PS) or mild SDB groups (p < 0.05 for both) and controls (p = 0.07).ConclusionsIn contrast to adults, nocturnal dipping is preserved in young children with SDB, despite increased sleep fragmentation. As there is evidence that nocturnal dipping is similarly preserved at the school age, childhood may pose a window of opportunity for resolution of SDB when the cardiovascular effects are less marked.     

Prevalence,clinical symptoms and polysomnographic findings of REM-related sleep disordered breathing in Japanese population

BackgroundRapid eye movement sleep -predominant sleep-disordered breathing (REM-SDB) is a condition in which sleep apneas or hypopneas predominantly occur during REM sleep. This study aimed to investigate the prevalence, clinical findings including daytime sleepiness or comorbid cardio-metabolic diseases, and detailed polysomnographic features of REM-SDB in Japanese population.MethodsTotal of 1458 patients diagnosed as SDB were selected for this study. Prevalence of REM-SDB was estimated in the groups of mild, moderate and severe SDB. Polysomnographic findings, daytime sleepiness self-measured with Epworth Sleepiness Scale (ESS) and history of comorbid cardio-metabolic diseases were obtained and compared between the groups with REM-SDB and non-stage specific SDB.ResultsPrevalence of REM-SDB according to the criteria #2 was 22.1% in total SDB subjects, 46,1% in mild SDB and 18.9% in moderate SDB. None was found in severe SDB. Patients with REM-SDB showed milder SDB, higher BMI and higher female predominance than those with non-stage specific SDB. They also showed lower arousal index, respiratory arousal index per total AHI, percentage of N1 sleep, total AHI, ODI, and higher sleep efficiency. Meanwhile, maximum event durations of obstructive apnea and hypopnea were significantly longer, and the nadir SpO₂ was lower in REM-SDB. The ESS score and percentages of comorbid cardio-metabolic diseases were roughly equivalent between REM-SDB and non-stage specific SDB.ConclusionREM-SDB was associated with high obesity, female gender, and mild severity of SDB. They showed daytime sleepiness and comorbid cardio-metabolic diseases quite equally to patients with non-stage specific SDB in spite of their lower AHI and better sleep quality.     

Sleep-disordered breathing among patients with first-ever stroke

Sleep-disordered breathing (SDB) in the form of obstructive sleep apnea is a possible risk factor for stroke. We carried out a cross-sectional survey out in a rehabilitation center among patients with first-ever stroke to further determine the incidence and types of SDB and its relationship to known risk factors for stroke. Full polysomnography was performed in 147 consecutive patients (95 men, 52 women, age 61+/-10 years) admitted to our neurological Rehabilitation Department 46+/-20 days after first-ever stroke. Subjective sleepiness (Epworth Sleepiness Scale), vascular risk factors, anthropometric data, and polysomnographic findings were compared between stroke patients with varying degrees of SDB. With a cutoff point for the respiratory disturbance index (RDI) of 5, 10, 15, or 20 the respective prevalence of SDB was 61%, 44%, 32%, and 22%. The type of SDB was generally obstructive, with dominant central apneas in only 6% of patients. Patients with an RDI of 20 or higher had less REM sleep, thicker necks, and a more central type of obesity. Even in patients with an RDI of 20 or higher subjective sleepiness, although higher than in those without SDB, was not a predominant symptom. Snoring and anthropometric data suggest that obstructive SDB may have existed prior to stroke. The prevalence of hypertension and coronary heart disease were higher among stroke patients with an RDI of 20 or higher than in those without SDB. We conclude that the prevalence of SDB among patients with stroke is high. Examination of stroke should include screening for SDB.     

Electrocardiographic variables in children with syndromic craniosynostosis and primary snoring to mild obstructive sleep apnea: significance of identifying respiratory arrhythmia during sleep

BackgroundIn the spectrum of children with symptomatic sleep disordered breathing (SDB), some individuals – such as those with upper airway resistance syndrome (UARS) – do not have abnormalities on polysomnography (PSG). In this study we have assessed whether assessment of respiratory arrhythmia (RA) and heart rate variability (HRV) analysis helps in management of children with syndromic craniosynostosis and none-to-mild obstructive sleep apnea (OSA).MethodsProspective cohort study in children aged 1–18 years old with syndromic craniosynostosis. Children were selected for HRV analysis from the ECG if their obstructive apnea–hypopnea index (oAHI) was between zero and five per hour (ie, oAHI ≤5/hour). Subjects were divided into groups based on the presence or absence of respiratory arrhythmia (with or without RA respectively) using the electrocardiogram (ECG). The main analysis included studying the relationship between RA and HRV, symptoms, interventions, and sleep architecture.ResultsWe identified 42 patients with, at worst, mild OSA. We found higher parasympathetic control and higher total power in children with RA during the non-rapid eye movement (non-REM) sleep. Children with RA also have a relatively higher percentage of paradoxical breathing during non-REM sleep (P = 0.042). Intracranial hypertension was distributed equally between groups. Last, RA patients showed increased parasympathetic activity that further increased in non-REM sleep.ConclusionIn syndromic craniosynostosis cases with SDB and PSG showing oAHI ≤5/hour, the presence of RA may indicate subsequent need for treatment interventions, and a trend toward higher occurrence of clinical symptoms. ECG analyses of HRV variables in subjects with RA demonstrate increased parasympathetic activity and total power. Such findings may add to the diagnosis of apparently asymptomatic children.     

Sleepiness and activity in heart failure patients with reduced ejection fraction and central sleep-disordered breathing

ObjectivePatients with heart failure (HF) and sleep disordered breathing (SDB) are typically not sleepy, unlike patients without heart failure. Previous work in HF patients with obstructive SDB suggested that sleepiness was associated with a reduction in daytime activity. The consequences of predominately central SDB on sleepiness in HF are less well understood. The aim of this study was to test the hypothesis that subjective sleepiness is associated with reduced daytime activity in HF patients with central SDB, compared to those without SDB.MethodsThe Epworth Sleepiness Scale (ESS), nocturnal polysomnography, and 14 days of wrist watch actigraphy were used to assess subjective daytime sleepiness, nocturnal sleep and breathing, and 24-h activity levels, respectively.ResultsA total of 54 patients with HF were studied, nine had obstructive SDB and were removed from further analysis. Of the patients, 23 had HF with predominantly central SDB (HF-CSA; apnea–hypopnea index (AHI) median 20.6 (IQR 12.9–40.2)/h), and 22 had noSDB (HF-noSDB; AHI 3.7 (2.5–5.9)/h). The median patient age was 68 years (range 59–73 years). There were no significant differences either in ESS score (HF-CSA; 8 [4–10] vs. HF-noSDB; 8 (6–12); p = 0.49) or in duration of daytime activity (HF-CSA 14.5 (14.1–15.2) and HF-noSDB 15.1 (14.4–15.3) hours; p = 0.10) between the groups.ConclusionHF patients with predominately central SDB are not subjectively sleepy compared to those without SDB, despite reduced sleep quality. We speculate that the lack of sleepiness (based on ESS score) may be due to increased sympathetic nerve activity, although further studies are needed due to the small number (n = 5) of sleepy HF-CSA patients. Daytime activity was not different between HF-noSDB and HF-CSA patients.     

Sleep disordered breathing in children: which symptoms do parents consider a problem?

Study objectiveParents tend to under-report symptoms suggestive of sleep disordered breathing (SDB) at medical consultation. It is thought that a contributing factor may be whether parents view SDB symptoms as a problem. The aim of the study was to examine to what extent parents view SDB symptoms as a problem in children recruited from the general community and especially in children who currently have symptoms suggestive of SDB.MethodsParents of 1639 children aged 5–10 y attending middle school in South Australia completed a questionnaire which included demographics and assessed the frequency over the previous school week of 32 sleep habits including six SDB sleep habit items. The sample was restricted to typically developing children and excluded children with medical problems likely to impact SDB. The final sample included 1610 children without a prior diagnosis of SDB and 29 with a prior diagnosis and/or treatment of SDB. Parents were asked to rate children's sleep habits using a 4-pt scale (never, rarely, sometimes and usually) and if the sleep habit was perceived to be a problem (yes/no). Children who sometimes or usually reported a sleep habit item were labelled as symptomatic.ResultsParents of children with, compared to those without, a prior diagnosis of SDB, were more likely to report the presence of SDB symptoms which were more frequently viewed as a problem. In children without a prior diagnosis of SDB, parents of symptomatic children viewed most SDB symptoms as a problem ranging from 91% for apnoea, 63% snorted/gasped, 63% watched child breathing at night, 58% snored loudly, 49% snored to 32% breathing heavily at night. Additional analyses in the combined sample revealed that a prior diagnosis of SDB, gender, socioeconomic status and ethnicity were weak predictors of whether parents viewed SDB sleep symptoms as a problem.ConclusionIn children with symptoms suggestive of SDB, most parents viewed most SDB symptoms as a problem especially apnoea. The high frequency is contrary to that expected given the under-reporting of SDB symptoms at medical consultation. This suggests that additional factors other than whether parents consider SDB symptoms as a problem might better explain the under-reporting of SDB symptoms at medical consultation. Given the important impact on child health and medical service provision, future studies examining the factors that prompt parents to discuss SDB symptoms at medical consultation are warranted.     

Nocturnal dipping of heart rate is impaired in children with Down syndrome and sleep disordered breathing

BackgroundChildren with Down syndrome (DS) are at increased risk for sleep disordered breathing (SDB), which can have adverse effects on the cardiovascular system. In adults with SDB, nocturnal dipping of heart rate (HR) and blood pressure (BP) is reduced, and this is associated with an increased risk of future cardiovascular events. We aimed to compare nocturnal dipping of HR and pulse transit time (PTT) (a surrogate inverse measure of BP change) in children with DS and SDB to those of typically developing (TD) children with and without SDB.Methods19 children with DS (3–18 years) were age and sex matched with 19 TD children without SDB (TD-) and with 19 TD children with matched severity of SDB (TD+). Nocturnal dipping was assessed as the percentage change in HR and PTT from wake before sleep onset to total sleep, N2, N3 and REM sleep across the night and to the first cycle of sleep.ResultsChildren with DS exhibited reduced nocturnal dipping of HR during total sleep, N2, N3 and REM sleep and increased PTT (reduced BP dipping) in N2 sleep. Fewer children with DS exhibited a greater than 10% fall in HR between wake and N2 or REM sleep compared to TD+ children.ConclusionsOur findings demonstrate significantly reduced nocturnal dipping of HR in children with DS compared to TD children matched for SDB severity, suggesting SDB has a greater cardiovascular effect in these children. Further studies are required to fully understand the mechanisms involved and to assess if treatment of SDB improves nocturnal dipping.     

Improvement of sleep-disordered breathing in children is associated with a reduction in overnight blood pressure

ObjectiveChildhood sleep-disordered breathing (SDB) is associated with elevated blood pressure (BP); however, little is known about the long-term outcomes in this population. We aimed to assess long-term changes in overnight BP in children with SDB.MethodsForty children with previously diagnosed SDB and 20 nonsnoring control participants underwent repeat overnight polysomnography (PSG) with continuous BP measurement 4 years after the original diagnosis. At follow-up, children aged 11–16 years were categorized into 2 groups of resolved (absence of snoring and obstructive apnea–hypopnea index [OAHI]⩽1) or unresolved (continued to snore or had an OAHI >1) SDB.ResultsThere were no group differences in age, sex, or body mass index (BMI) z score. OAHI was lower at follow-up (P < .05) in both the resolved (n = 18) and unresolved (n = 22) groups. BP was elevated during wake and sleep in both SDB groups compared to the control group at baseline (P < .01 for all), but it decreased by 5–15 mmHg at follow-up during sleep for both SDB groups (P < .05 for all). BP during wake was unchanged in the SDB groups at follow-up but increased in the control group (P < .05). At follow-up, BP did not differ between the control group and the SDB groups during wake or sleep. Improved oxygen saturation (SpO₂) during sleep was a significant predictor of a reduction in BP.ConclusionsSDB improved over the 4-year follow-up and both resolved and unresolved groups exhibited a significant reduction in BP during sleep, with levels similar to the control group. Our study highlights the fact that even small improvements can improve the cardiovascular effects of SDB.     

Sleep disordered breathing in children receiving vagus nerve stimulation therapy

ObjectiveThe effects of vagus nerve stimulation (VNS) on sleep disordered breathing (SDB) have been reported in limited case series. Detailed studies, particularly in the pediatric population, have not been performed. The primary purpose of this study is to describe clinical characteristics, polysomnographic findings, and management of children treated with VNS.MethodsA retrospective review of medical records and polysomnography data was performed in patients ages 0–20 years old receiving VNS therapy for refractory epilepsy at Cincinnati Children's Hospital Medical Center.Results22 subjects met the inclusion criteria. 50% were male. The mean age at the time of VNS insertion was 8.4 ± 4.0 years. The mean age at the first PSG was 10.6 ± 4.3 years. Common presentations to sleep clinics included snoring (77.3%), frequent nighttime awakening (68.1%), and parasomnias (63.6%). The median apnea-hypopnea index (AHI) was 4.5/hr (IQR 3.0–13.1) and the median obstructive index (OI) was 4.1/hr (1.5–12.8). Obstructive sleep apnea (OSA) was diagnosed after VNS insertion in 19 patients (86.4%), 8 of which (36.3%) had severe OSA. Six patients (27.3%) had significant hypoventilation. For management, 6 patients (27.2%) were treated with bilevel PAP, 3 patients (13.6%) with CPAP, 2 patients (9.1%) with ventilator, 4 patients (18.2%) with upper airway surgeries, and 9 patients (40.9%) received medications only.ConclusionsSDB is common in pediatric patients with medically refractory epilepsy managed with VNS who were referred to sleep medicine clinics. Both OSA and nocturnal alveolar hypoventilation are relatively common in this population. Management of SDB often involves the use of positive airway pressure therapy or upper airway surgeries. Further studies are needed to assess the prevalence, risk factors, and the effect of treatments on epilepsy control. This study highlights the need for screening of SDB prior to and following VNS implantation.     

Continuous positive airway pressure improves work of breathing in pediatric chronic heart failure

BackgroundSleep disordered breathing (SDB) is common in adults with chronic heart failure (CHF), but its prevalence in children remains unclear. Continuous positive airway pressure (CPAP) is the treatment of SDB but deleterious hemodynamic effects have been reported.MethodsWe prospectively analyzed SDB in children with CHF and the effect of CPAP on work of breathing (WOB) and cardiac index (CI). Children aged 6 months to 18 years old with CHF due to: 1) dilated cardiomyopathy (DM) with an ejection fraction < 45%, 2) functional single ventricle (SV) or 3) aortic or mitral valve disease awaiting surgery (VD) were eligible for the study. A polysomnography (PSG), measurement of WOB and CI during spontaneous breathing (SB) and CPAP (6, 8 and 10 cmH₂O) were performed.ResultsThirty patients with mean age of 6.4 ± 5 years were included (16 DM 16, 10 SV, 4 LV). Twenty (73%) patients had a normal sleep efficiency. Median apnoeas hypopnea index (IAH) was within normal range at 1.6 events/h (0, 14) events/hour. Only one patient had central sleep apnoeas, none had Cheyne-Stokes respiration, and 3 patients had an obstructive AHI between 5 and 10 events/hour. Optimal CPAP level decreased WOB (p = 0.05) and respiratory rate (p = 0.01).ConclusionsSevere SDB was uncommon in children with CHF. However, CPAP may be beneficial by decreasing WOB and respiratory rate without deleterious effects on CI.     

Episodic hypoxia exacerbates respiratory muscle dysfunction in DMD(mdx) mice

Many patients with Duchenne muscular dystrophy (DMD) are eventually diagnosed with sleep-disordered breathing (SDB). SDB is associated with reduced ventilation, decreased arterial oxygen tension, and increased respiratory muscle recruitment during sleep, factors that could be especially detrimental to respiratory muscles in DMD. To assess whether SDB impacts dystrophin-deficient respiratory muscle function and fibrosis, diaphragm strength, and collagen content were evaluated in dystrophic mice (Dmd(mdx)) exposed to experimental SDB. Diurnal exposure to episodic hypoxia resulted in a 30% reduction in diaphragm strength without affecting collagen content. Episodic hypoxia secondary to SDB can exacerbate respiratory muscle dysfunction in DMD.     

Prevalence and characteristics of sleep-disordered breathing in familial dysautonomia

ObjectiveFamilial dysautonomia (FD) is an autosomal recessive disorder characterized by impaired development of sensory and afferent autonomic nerves. Untreated sleep-disordered breathing (SDB) has been reported to increase the risk of sudden unexpected death in FD. We aimed to describe the prevalence and characteristics of SDB in FD.Patients/MethodsSeventy-five patients with FD (20 adults and 55 children) underwent in-lab polysomnography, including peripheral capillary oxygen saturation (SpO₂) and end-tidal capnography (EtCO₂) measurements. A t-test and Spearman's correlation analysis were performed to evaluate the impact of age on sleep, occurrence of apneas, SpO₂ and EtCO₂ levels; and to determine the relationship between apneas and SpO₂/EtCO₂ measurements during different sleep stages.ResultsOverall, 85% of adults and 91% of pediatric patients had some degree of SDB. Obstructive sleep apneas were more severe in adults (8.5 events/h in adults vs. 3.5 events/h in children, p = 0.04), whereas central apneas were more severe (10.8 vs. 2.8 events/h, p = 0.04) and frequent (61.8% vs. 45%, p = 0.017) in children. Overall, a higher apnea–hypopnea index was associated with increased severity of hypoxia and hypoventilation, although in a significant fraction of patients (67% and 46%), hypoxemia and hypoventilation occurred independent of apneas.ConclusionMost adult and pediatric patients with FD suffer from some degree of SDB. There was a differential effect of age in the pattern of SDB observed. In some FD patients, hypoventilation and hypoxia occurred independently of apneas. Therefore, we recommend including EtCO₂ monitoring during polysomnography in all patients with FD to detect SDB.     

Comorbid Insomnia and Sleep Apnea: mechanisms and implications of an underrecognized and misinterpreted sleep disorder

Sleep-disordered breathing (SDB) and insomnia have long been recognized as important sleep disrupters often associated with increased morbidity and mortality. Although they are often seen as divergent conditions, mainly because their cardinal symptoms (excessive daytime sleepiness, and sleep loss) differ, these two sleep disorders present with many common symptoms, which may hinder diagnosis and treatment. In addition to possible bidirectional pathways between SDB and insomnia, other factors such as circadian timing may play a role. In this paper, we review the mechanisms, differential clinical aspects, and implications of Comorbid Insomnia and Sleep Apnea, sometimes termed COMISA.     

Upper-airway flow limitation and transcutaneous carbon dioxide during sleep in normal pregnancy

ObjectiveSleep during pregnancy involves a physiological challenge to provide sufficient gas exchange to the fetus. Enhanced ventilatory responses to hypercapnia and hypoxia may protect from deficient gas exchange, but sleep-disordered breathing (SDB) may predispose to adverse events. The aim of this study was to analyze sleep and breathing in healthy pregnant women compared to non-pregnant controls, with a focus on CO₂ changes and upper-airway flow limitation.MethodsHealthy women in the third trimester and healthy non-pregnant women with normal body mass index (BMI) were recruited for polysomnography. Conventional analysis of sleep and breathing was performed. Transcutaneous carbon dioxide (TcCO₂) was determined for each sleep stage. Flow-limitation was analyzed using the flattening index and TcCO₂ values were recorded for every inspiration.ResultsEighteen pregnant women and 12 controls were studied. Pregnancy was associated with shorter sleep duration and more superficial sleep. Apnea–hypopnea index, arterial oxyhemoglobin desaturation, flow-limitation, snoring or periodic leg movements were similar in the two groups. Mean SaO₂ and minimum SaO₂ were lower and average heart rate was higher in the pregnant group. TcCO₂ levels did not differ between groups but variance of TcCO₂ was smaller in pregnant women during non-rapid eye movement (NREM). TcCO₂ profiles showed transient TcCO₂ peaks, which seem specific to pregnancy.ConclusionsHealthy pregnancy does not predispose to SDB. Enhanced ventilatory control manifests as narrowing threshold of TcCO₂ between wakefulness and sleep. Pregnant women have a tendency for rapid CO₂ increases during sleep which might have harmful consequences if not properly compensated.     

Is there a link between the severity of sleep‐disordered breathing and atherosclerotic disease of the carotid arteries?

Epidemiological studies have shown a strong association between sleep-disordered breathing (SDB) and cerebrovascular diseases. A total of 114 male patients, aged 40-65 years, referred to sleep laboratory for the evaluation of snoring and disturbed sleep were studied. Subjects were divided into three groups: habitual snoring, mild-moderate and severe obstructive sleep apnea syndrome (OSAS), respectively, determined by using three respiratory disturbance index (RDI) cut points (/=30). Measurement of intima-media thickness (IMT) and the presence of plaque were determined by ultrasonographic evaluation. Major vascular risk factors such as hypertension, diabetes, smoking, hyperlipidemia, and obesity were determined. The OSA groups had significantly higher IMT values compared with the habitual snoring group. Three groups were significantly different with regard to the presence of plaque. Age and body mass index were found to be significantly associated with IMT while age and RDI were found to be most probably predictive for plaque. There were no significant differences amongst the three groups with respect to age, prevalence of hypertension and diabetes, smoking, total cholesterol and total triglyceride levels. These findings suggested that SDB is a predisposing factor for the atherosclerotic process and precipitate plaque particularly when associated with higher RDI.     

Clinical prediction of periodic leg movements during sleep in children

OBJECTIVE: To assess the utility of several symptoms and a questionnaire-based scale in the identification of children with periodic leg movements during sleep (PLMS). BACKGROUND: PLMS may have important consequences in some children, but the extent to which a diagnosis can be established by clinical history is unknown. METHODS: Subjects were patients aged 2-18 years who underwent polysomnography to assess for sleep-disordered breathing (SDB). Parents completed a Pediatric Sleep Questionnaire which contained items under consideration for inclusion in the desired scale. RESULTS: Subjects (n=113) had a mean age of 9.8+/-4.0 (SD) and 73 (65%) were male; 59 (52%) had SDB and 29 (26%) had five or more PLMS per hour of sleep (PLMI> or =5). Severity of SDB was not different among those with and without PLMI> or =5. Yes/no responses to several question-items--about restless legs, growing pains, leaving the bed at night, waking more than twice per night, waking feeling unrefreshed, and morning headaches--showed some association with PLMI> or =5 and were combined into a composite PLMS score artificially weighted toward the first two items. The PLMS score averaged 0.40+/-0.31 and ranged from 0.0 to 1.0; a 1 SD increase was associated with PLMI> or =5 (odds ratio=1.87, 95% confidence interval (1.15, 3.13), P=0.014) after adjustment for age, sex, and SDB severity. Sensitivity of a PLMS score>0.33 for PLMI> or =5 was 0.79, specificity was 0.56, positive predictive value was 0.38, and negative predictive value was 0.89. Internal consistency was reasonable (Cronbach's alpha=0.71), as was test-retest reliability (rho=0.62, P=0.0026, n=21 separate subjects). CONCLUSIONS: Restless legs, growing pains, sleep-maintenance insomnia, unrefreshing sleep, and morning headaches show moderate associations with polysomnographically-defined PLMS, but several other symptoms do not. These results require confirmation but suggest that clinical assessment and the PLMS score may be helpful but far from definitive.     

Effect of respiration on heartbeat-evoked potentials during sleep in children with sleep-disordered breathing

ObjectiveHeartbeat-evoked potentials (HEPs) in electroencephalogram (EEG) provide a quantitative measure of cardiac interoception during sleep. We previously reported reduced HEPs in children with sleep-disordered breathing (SDB), indicative of attenuated cardiac information processing. The objective of this study was to investigate the link between HEP and respiration.Patients/MethodsFrom the overnight polysomnograms of 40 healthy children and 40 children with SDB, we measured HEPs during epochs of stage 2, slow-wave and rapid eye movement (REM) sleep free of abnormal respiratory events. HEPs were analysed with respect to respiratory phase.ResultsWe observed a marked association between respiratory phase and HEP in children with SDB during REM sleep, but not in normal children. In children with SDB, HEP waveforms were attenuated during expiration compared to inspiration. Following adenotonsillectomy, expiratory HEP peak amplitude increased in the SDB children and was no longer different from those of normal children.ConclusionsThe expiratory phase of respiration is primarily associated with attenuated cardiac information processing in children with SDB, establishing a pathophysiological link between breathing and HEP attenuation.     

The effect of seasonality on sleep-disordered breathing severity in children

Objective

Sleep-disordered breathing (SDB) is a common disorder associated with substantial morbidity that occurs in otherwise healthy children. Atopy, asthma, and viral upper respiratory tract infections are known risk factors for pediatric SDB that exhibit seasonal variability. The aim of our study was to investigate the effect of seasonality on SDB severity in children and adolescents referred for polysomnographic evaluation for suspected SDB and to examine the effect of atopy/asthma on this variability.

Methods

The medical records of all children and adolescents referred for a polysomnography (PSG) for suspected SDB between 2008 and 2010 were retrospectively assessed for seasonal patterns. The effect of atopy/asthma, age, and obesity on seasonal variability was investigated.

Results

A total of 2178 children and adolescents (65% boys) were included. The mean age of the cohort was 4.9 ± 3.5 years (range, 3 months–18 years). Eighteen percent of patients had a history of asthma/atopy. The mean obstructive apnea–hypopnea index (OAHI) in the winter was significantly higher compared to the summer (9.1 ± 9.6 vs 7.5 ± 7.0; P = .01; Cohen d = 0.19), particularly in children younger than the age of 5 years (10.2 ± 10.5 vs 7.9 ± 7.3; P = .008; Cohen d = 0.25). Asthma/atopy had no significant effect on seasonal variability.

Conclusions

SDB severity alters in a season-dependent manner in children and adolescents referred for polysomnographic evaluation for suspected SDB. These alterations are more prominent in children younger than the age of 5 years. The presence of asthma/atopy does not contribute to this seasonal variability. These findings suggest that viral respiratory infections are most likely the major contributor for the seasonal variability observed in pediatric SDB; additionally, the time of the year when a child is evaluated for suspected SDB may affect the clinical management and outcome in borderline cases.     

Are there gender differences in the severity and consequences of sleep disordered in children?

ObjectivesIn adults there is a distinct gender difference in the prevalence and severity of sleep disordered breathing (SDB), however there have been limited studies examining the effects of gender in children with SDB. We aimed to compare the effects of gender on severity of SDB, blood pressure, sleep and respiratory characteristics, quality of life, behavior and executive function.MethodsWe included 533 children aged 3–18 years, who underwent standard pediatric overnight polysomnography (PSG) between 2004 and 2016. Blood pressure was recorded prior to each study. Quality of life, behavior and executive function were assessed with parental questionnaires. Children were grouped by gender and SDB severity based on their obstructive apnea hypopnea index (OAHI) into non-snoring controls, Primary Snoring (PS) (OAHI≤1 event/h), Mild obstructive sleep apnea (OSA) (OAHI>1-≤5 events/h) and moderate/severe (MS) OSA (OAHI>5 events/h) and data compared with 2-way ANOVA.ResultsA total of 298 boys and 235 girls were studied. There were no differences in age, BMI z-score, SDB severity sleep characteristics or blood pressure between genders. Diastolic blood pressure was elevated in females with MS OSA compared to males (P < 0.05). Quality of life, behavior and executive function scores were all elevated in the SDB groups compared to controls. Females with MS OSA exhibited more internalizing behavioral problems compared to males (59.2 ± 2.4 vs. 51.4 ± 2.3, P < 0.05).ConclusionsIn contrast to studies in adults, we identified no gender differences in the severity or consequences of SDB in children, other than females with moderate-severe OSA exhibiting more internalizing problems and higher diastolic blood pressure.