Sleep macro-architecture and micro-architecture in children born preterm with sleep disordered breathing.

BACKGROUND: Both preterm birth and sleep disordered breathing (SDB) affect sleep in children. We compared the effects of SDB on sleep macro-architecture and micro-architecture in children born preterm (N = 50) and children born at term (N = 50). We hypothesized that sleep would be more disrupted in children born preterm. METHODS: Polysomnographic studies matched for age (3-12 years) and SDB severity were analyzed. Sleep macro-architecture was assessed using standard criteria and micro-architecture was evaluated using spectral analysis of the electroencephalogram and slow wave activity (SWA) calculated for each sleep stage across the night. RESULTS: Ex-preterm children (gestational age 29.3 ± 3.6 weeks, mean ± standard error of the mean) were not different from controls for demographic or respiratory parameters or sleep macro-architecture. Theta power in N2 tended to be higher for F4 (p < 0.05) and C4 (p < 0.07). In the second non-rapid eye movement period, SWA was significantly higher in the preterm group compared to the term group for both F4 and C4 (p < 0.05 for both). CONCLUSIONS: Sleep micro-architecture in children born preterm showed increased theta power and SWA. These differences provide evidence of increased sleep debt and reduced dissipation of sleep debt across the night. Further studies are required to identify if these findings are related to impaired neurocognition and behavior.

Role of ventilatory control instability in children with sleep-disordered breathing.

BACKGROUND AND OBJECTIVE: The contribution of non-anatomical factors, such as ventilatory control instability (i.e. LG), to the pathogenesis of obstructive SDB in children is unclear. Therefore, we aimed to identify the relationship between LG and severity of SDB, demographic, anthropometric and anatomical characteristics in a clinically representative cohort of children. METHODS: Children (aged 3-18 years) with various severities of SDB (n = 110) and non-snoring controls (n = 36) were studied. Children were grouped according to their OAHI. Anthropometric and upper airway anatomical characteristics were measured. Spontaneous sighs were identified on polysomnography and LG, a measure of the sensitivity of the negative feedback loop that controls ventilation, was estimated by fitting a mathematical model of ventilatory control to the post-sigh ventilatory pattern. RESULTS: There was no difference in LG between controls and any of the SDB severity groups. However, LG was significantly lower in children with larger tonsils (tonsil grade 4) compared with children with smaller tonsils (tonsil grade 1) (median LG (range): 0.25 (0.20-0.42) vs 0.32 (0.25-0.44); P = 0.009) and in children with a modified Mallampati score of class III/IV compared with class I (0.28 (0.24-0.33) vs 0.37 (0.27-0.44); P = 0.009). CONCLUSION: A direct relationship was not found between the severity of paediatric SDB and LG. However, an altered ventilatory control sensitivity may contribute to SDB in a subgroup of children depending on their degree of anatomical compromise of the airway.

Assessing ventilatory control stability in children with and without an elevated central apnoea index.

BACKGROUND AND OBJECTIVE: Frequent central apnoeas are sometimes observed in healthy children; however; the pathophysiology of an elevated central apnoea index (CAI) is poorly understood. A raised CAI may indicate underlying ventilatory control instability (i.e. elevated loop gain, LG) or a depressed ventilatory drive. This pilot study aimed to compare LG in otherwise healthy children with an elevated CAI to healthy controls. METHODS: Polysomnographic recordings from children (age > 6 months) without obstructive sleep apnoea and with a CAI > 5 events/h (n = 13) were compared with age and gender-matched controls with a CAI < 5 events/h (n = 13). Spontaneous sighs were identified during non-rapid eye movement (NREM) sleep, and breath-breath measurements of ventilation were derived from the nasal pressure signal. A standard model of ventilatory control (gain, time constant and delay) was used to calculate LG by transforming ventilatory fluctuations seen in response to a sigh into a ventilatory-drive signal that best matches observed ventilation. RESULTS: The high CAI group had an elevated LG (median = 0.36 (interquartile range, IQR = 0.35-0.53) vs 0.28 (0.23-0.36); P ≤ 0.01). There was no difference in either the time constant (P = 0.63) or delay (P = 0.29) between groups. Elevated LG observed in the high CAI group remained after accounting for degree of hypoxia (average oxygen saturation (SpO2 ) during each analysable window) experienced (0.40 (0.30-0.53) vs 0.25 (0.23-0.37); P = 0.04). CONCLUSION: An elevated CAI in otherwise healthy children is associated with a raised LG compared to matched controls with a low CAI, irrespective of level of hypoxia. This relative ventilatory instability helps explain the high CAI and may ultimately be able to help guide diagnosis and management in patients with high CAI.

Craniofacial photography and association with sleep-disordered breathing severity in children.

PURPOSE: Sleep-disordered breathing (SDB) in children has been associated with craniofacial characteristics. Facial photography provides a radiation-free means of estimating facial morphology through facial landmark analysis. Our objective was to determine whether facial analysis provides information about SDB severity. Specifically, we aimed to determine whether facial photographic measurements differ with SDB status, or were associated with SDB severity. METHODS: Single-center cohort of children undergoing overnight polysomnography for assessment of SDB; non-snoring controls were recruited from the community to undergo polysomnography. Standardized front and lateral facial photographs were analyzed according to previously published protocols. Multivariate analysis of variance was used to determine if facial measurements differed between SDB groups and controls. Linear regression was performed to determine if facial measurements were associated with SDB severity. RESULTS: Seventy-eight children (9 controls, 17 primary snoring, 23 mild SDB, 27 moderate-severe SDB) were included. Facial angles and upper-to-lower face height ratio showed variation between SDB groups (p = 0.038). Facial measurements related to SDB severity, specifically an increased cervicomental angle (p = 0.001), and increased lower-to-upper face height (p = 0.006). CONCLUSION: Evaluation of craniofacial features using clinical photography is feasible. Preliminary investigation shows some relationship with SBD severity. Further work is needed to determine if craniofacial photography is useful for stratifying SDB risk in children.

Sleep disordered breathing in children disrupts the maturation of autonomic control of heart rate and its association with cerebral oxygenation.

KEY POINTS: Sleep disordered breathing (SDB) affects 4-11% of children and is associated with adverse neurocognitive, behavioural and cardiovascular outcomes, including reduced autonomic control. The relationship between heart rate variability (HRV; a measure of autonomic control) and age found in non-snoring control children was absent during sleep in children with SDB. Age significantly predicted increasing cerebral oxygenation during wake in non-snoring control children, whereas during sleep, HRV significantly predicted decreasing cerebral oxygenation. Cerebral oxygenation was not associated with either age or HRV in children with SDB during both wake and sleep. SDB significantly disrupts the normal maturation of autonomic control and the positive association between autonomic control and cerebral oxygenation found in non-snoring children, and we speculate that the dampened autonomic control exhibited by children with SDB may have an attenuating effect on cerebral autoregulation via the moderating influence of HRV on cerebral blood flow. ABSTRACT: The repetitive episodes of hypoxia that are features of sleep disordered breathing (SDB) in children are associated with alterations in autonomic control of heart rate in an age-dependent manner. We aimed to relate heart rate variability (HRV) parameters to age and measures of cerebral oxygenation in children (3-12 years old) with SDB and non-snoring controls. Children (SDB, n = 117; controls, n = 42; 3-12 years) underwent overnight polysomnography. Total (TP), low- (LF) and high-frequency (HF) power, tissue oxygenation index (TOI) and fractional tissue oxygen extraction (FTOE) were analysed during wake and sleep. Pearson's correlations determined the association between age and HRV parameters, and multiple linear regressions between HRV, age and cerebral oxygenation parameters. During wake, age had a positive association with LF power, reflecting increased parasympathetic and sympathetic activity with increasing age for both control and SDB groups. This association was also evident during sleep in controls, but was absent in children with SDB. In controls, during wake TOI had a positive, and FTOE a negative association with age. During sleep, TP, LF and HF power were significant, negative determinants of TOI and positive determinants of FTOE. These associations were not seen in children with SDB during wake or sleep. SDB disrupts the normal maturation of the autonomic control of heart rate and the association between HRV and cerebral oxygenation exhibited by non-snoring control children of primary school age. These results highlight the impact SDB has on cardiovascular control and the potential impact on adverse cardiovascular outcomes.

Cardiovascular Autonomic Control Is Altered in Children Born Preterm with Sleep Disordered Breathing.

BACKGROUND: To assess if the effects of sleep disordered breathing (SDB) on heart rate (HR) and HR variability, as a measure of autonomic control, were more severe in a group of children born preterm compared with a group of children born at term referred to our sleep laboratory for assessment of SDB. STUDY DESIGN: Children (3-12 years of age) referred for polysomnographic assessment of SDB were recruited; 50 born preterm (<37 weeks of gestation) and 50 at term, matched for age and SDB severity. The mean HR and HR variability using power spectral analysis were calculated for each child for wake and sleep, and stages N1, N2, N3, and rapid eye movement sleep. RESULTS: Ex-preterm children were born between 23 and 35 weeks of gestational age (29.3 ± 3.6; mean ± SEM). There were no differences in the demographic, sleep, or respiratory characteristics between the groups. High-frequency power (reflecting parasympathetic activity) was greater in the ex-preterm children in both N2 and N3 (P < .05 for both) and total power was greater in N3 (P < .05). When the children were divided by SDB severity, these effects were most marked in those preterm born children with moderate to severe disease. CONCLUSIONS: Preterm born children matched for age and SDB severity with children born at term showed no differences in sleep characteristics; however, they did exhibit increased parasympathetic tone during non-rapid eye movement sleep.

Age Effects on Cerebral Oxygenation and Behavior in Children with Sleep-disordered Breathing.

RATIONALE: Childhood sleep-disordered breathing ranges in severity from primary snoring to obstructive sleep apnea and is associated with behavioral and neurocognitive deficits. It remains unknown why children with primary snoring, who do not experience peripheral oxygen desaturation or sleep fragmentation, experience similar daytime deficits as those with obstructive sleep apnea or why effects are age-dependent. OBJECTIVES: To examine cerebral tissue oxygenation and oxygen extraction as an explanation for daytime deficits in children with primary snoring. METHODS: Children referred for suspected sleep-disordered breathing and nonsnoring control subjects underwent overnight polysomnography with near-infrared spectroscopy. Children were categorized into 3- to 6-year (n = 87) and 7- to 12-year (n = 72) old groups, and according to the obstructive apnea-hypopnea index into primary snoring (≤1 event/h), mild (>1-5 events/h), and moderate/severe obstructive sleep apnea (>5 events/h). Cognitive and behavioral performance were assessed. MEASUREMENTS AND MAIN RESULTS: In the 3- to 6-year group, there were no differences in cerebral oxygenation or oxygen extraction between severity groups. In the 7- to 12-year group, cerebral oxygenation was significantly lower, although these differences were small, in control subjects versus primary snoring during quiet wakefulness before sleep onset, N1, and REM. Oxygen extraction was significantly higher in control subjects versus primary snoring during N1 sleep, with no differences between primary snoring and obstructive sleep apnea groups. Cerebral oxygenation was not associated with cognitive performance in either age group or behavior in the 3- to 6-year group; however, it was associated with behavior in the school-aged children. CONCLUSIONS: Children with sleep-disordered breathing are able to maintain cerebral oxygenation, and the small changes observed are not related to cognitive deficits. However, in older children these differences were related to behavioral measures.

Pollen levels on the day of polysomnography influence sleep disordered breathing severity in children with allergic rhinitis.

PURPOSE: Allergic rhinitis (AR) is a common risk factor for sleep disordered breathing (SDB) in children. Allergy to pollen is a trigger for allergic rhinitis, causing nasal inflammation, upper airway congestion and obstruction. We aimed to determine if the pollen count on the day of diagnostic polysomnography for SDB affected the result. METHODS: Children (3-18 years; n = 90) who participated in research studies between 1 October and 31 December, when daily regional pollen counts were available, in the years 2005-2016 were eligible for inclusion. All children underwent overnight polysomnography for assessment of SDB severity. Pollen was categorised as grass or other pollen. Multiple stepwise linear regression was performed to determine whether the pollen count for that day, a diagnosis of asthma, age, and BMI-z-score were determinants of respiratory parameters measured on polysomnography, including the obstructive apnoea hypopnoea index (OAHI), SpO2 nadir, average SpO2 drop, SpO2 < 90%, oxygen desaturation index > 4% (ODI4), and average transcutaneous CO2 (TCM). RESULTS: Sixteen/90 children had AR. In children with AR, an increase in grass pollen of 1 grain/m3 predicted an increase in OAHI of 0.2 events/h, ODI4 of 0.18 times/h, SpO2 < 90% of 0.03 times/h, and TCM of 0.07 mmHg. None of the factors were determinants of SDB severity in children without AR. CONCLUSION: Our findings highlight that daily pollen counts may be an important factor influencing the severity of SDB on a single night of polysomnography in children with clinical allergic rhinitis and should be taken into account when determining treatment options.

Slow wave activity and executive dysfunction in children with sleep disordered breathing.

PURPOSE: This study aimed to examine slow wave activity (SWA), a marker of homeostatic regulation, as a potential mechanism linking sleep disordered breathing (SDB) with executive dysfunction in children. METHODS: Executive function domains of working memory, spatial planning, information processing, and sustained attention were assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB) in children (N = 40; 5-12 years) referred for clinical diagnosis of SDB. Polysomnography records of non-snoring, age-matched controls (N = 34) were retrospectively examined for comparison of SWA. Power spectral analysis of the delta wave determined SWA. Group differences in sleep, respiratory, and SWA outcomes were examined. Mean CANTAB scores were compared to standardized norms and correlated against SWA. RESULTS: Children with SDB showed increased SWA compared to non-snoring controls and scored < 25th percentile for planning accuracy, speed of mental processing, and task efficiency, when compared against population norms. Increasing severity of SDB was associated with an increased difficulty in solving complex tasks and time on task performance. SWA was associated with performance on tasks of early problem solving and efficiency during sustained attention. CONCLUSIONS: SWA, a subtle measure of sleep disruption and sleep regulation, is associated with deficits in problem solving and sustained attention in children with SDB. As current mechanistic theories do not account for deficits observed in children with mild forms of SDB, this study provides a promising alternative.

Improved long-term autonomic function following resolution of sleep-disordered breathing in preschool-aged children.

PURPOSE: Sleep-disordered breathing (SDB) prevalence peaks in preschool children and is associated with deficits in cardiovascular functioning during sleep. No long-term studies have investigated the effects of SDB resolution in mitigating these outcomes. We hypothesized that following 3 years, normalization of alterations to heart rate (HR), pulse transit time (PTT), heart rate variability (HRV), and urinary catecholamines identified at the initial diagnosis would be associated with resolution of SDB. METHODS: Forty-five children with SDB and 28 non-snoring controls underwent polysomnography at baseline (3-5 years) and follow-up (6-9 years). Children were classified into control, resolved, and unresolved SDB. Resolution was defined as an obstructive apnea-hypopnea index (OAHI) ≤1 event/h, no snoring on polysomnography (PSG), or indicated by parents. PTT is an inverse surrogate measure of blood pressure change. HRV was assessed using power spectral analysis. RESULTS: There was no change in PTT or HR between studies for any group. Our HRV data suggest reduced parasympathetic activity in children whose SDB resolved and increased parasympathetic activity in children whose SDB remained the same or worsened at follow-up. We identified a significant correlation between low frequency power and urinary dopamine and adrenaline levels at follow-up in the unresolved group, suggesting increased sympathetic activity in children with unresolved SDB. CONCLUSION: Our findings suggest an association between resolution of SDB and normalization of HRV in the long term in these preschool children and an augmented sympathetic activity in the children with residual SDB. This highlights the autonomic impact of SDB in young children and the importance of detection and treatment.

Longitudinal Impact of Resolution of Snoring in Young Children on Psychosocial Functioning.

OBJECTIVE: To determine whether sustained resolution of sleep disordered breathing (SDB) in young children, either because of treatment or spontaneous recovery, predicted long-term improvements in quality of life, family functioning, and parental stress. STUDY DESIGN: Children diagnosed with primary snoring (n = 16), mild obstructive sleep apnea (OSA, n = 11), moderate-severe (MS) OSA (n = 8), and healthy nonsnoring controls (n = 25) at ages 3-5 years underwent repeat polysomnography at 6-8 years. Parents completed quality of life and parental stress questionnaires at both time points. Resolution of SDB was determined as obstructive apnea hypopnea index (OAHI) ≤1 event/hour, or absence of snoring during polysomnography or on parent report. Linear mixed-model analyses determined the effects of resolution on psychosocial morbidity. OAHI was used to determine the predictive value of changes in SDB severity on psychosocial outcomes. RESULTS: Fifty percent of primary snoring, 45% mild OSA, and 63% MS OSA resolved, of which 67% received treatment. Children originally diagnosed with SDB continued to show significant psychosocial impairments compared with nonsnoring controls, irrespective of resolution. A reduction in OAHI predicted improvements in physical symptoms, school functioning, family worry and family relationships, and stress related to a difficult child. CONCLUSIONS: Treatment was more likely to result in resolution of SDB if original symptoms were MS. Children originally diagnosed with SDB, irrespective of resolution, continued to experience psychosocial dysfunction suggesting additional interventions are required.

Augmented cardiovascular responses to episodes of repetitive compared with isolated respiratory events in preschool children with sleep-disordered breathing.

BACKGROUND: Childhood sleep disordered breathing (SDB) presents as isolated respiratory events or episodes of consecutive repetitive events. We hypothesized that the surge in blood pressure (BP) and heart rate (HR) would be greater at the termination of events during episodes of repetitive events than following isolated events. METHODS: % change in HR and pulse transit time (PTT; inverse surrogate of BP) were calculated from the last half of an event to: (i) between successive repetitive events; (ii) termination of the last repetitive event; (iii) event termination for isolated events. RESULTS: 69% of the children exhibiting both isolated and repetitive events had more repetitive than isolated events. %HR change between repetitive events (27 ± 1%) was greater than at event termination for isolated events (17 ± 1%; P < 0.001). %PTT change at the termination of the last repetitive event (-8 ± 2%) was greater than at the termination of isolated events (-2 ± 2%; P < 0.05). CONCLUSION: Episodes of repetitive respiratory events evoke a greater acute cardiovascular response, including surges in BP and HR between events, than do isolated events. Given that the majority of respiratory events in preschool children occur as repetitive episodes, this finding should be taken into account when assessing the impact of respiratory events for a given child.

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

OBJECTIVES: In 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. METHODS: We 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. RESULTS: A 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). CONCLUSIONS: In 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.

The impact of central and obstructive respiratory events on cerebral oxygenation in children with sleep disordered breathing.

STUDY OBJECTIVES: Both central and obstructive respiratory events are features of sleep disordered breathing. The repetitive hypoxia associated with obstructive events is believed to underpin the adverse neurocognitive and cardiovascular sequelae of this disorder, however whether central events contribute to this has not been investigated. To compare changes in cerebral and peripheral oxygenation, blood pressure and heart rate, associated with central and obstructive events in children aged 3-6 and 7-12 years. METHODS: Sixty children referred for suspected sleep disordered breathing underwent overnight polysomnography. Beat-by-beat analysis determined changes from baseline in cerebral oxygenation, peripheral oxygen saturation, fractional tissue oxygen extraction, pulse transit time (a surrogate measure of blood pressure change), and heart rate, associated with central and obstructive respiratory events, during NREM and REM sleep. RESULTS: Eight hundred ninty-two events were analyzed: 493 central and 399 obstructive. Central events had a greater % change from baseline in cerebral oxygenation and heart rate nadir compared with obstructive events and these were greater in NREM compared with REM sleep. The 3- to 6-year-old children experienced a greater % change in TOI compared with the 7-12 year olds, while % change in heart rate was greater in 7-12 year olds. CONCLUSION: Central respiratory events had similar falls in cerebral oxygenation and heart rate to obstructive events and should be considered when examining the sequelae of sleep disordered breathing, particularly as central events are common in children with sleep disordered breathing.

Age and autonomic control, but not cerebral oxygenation, are significant determinants of EEG spectral power in children.

STUDY OBJECTIVES: Sleep disordered breathing (SDB) in children has significant effects on daytime functioning and cardiovascular control; attributed to sleep fragmentation and repetitive hypoxia. Associations between electroencephalograph (EEG) spectral power, autonomic cardiovascular control and cerebral oxygenation have been identified in adults with SDB. To date, there have been no studies in children. We aimed to assess associations between EEG spectral power and heart rate variability as a measure of autonomic control, with cerebral oxygenation in children with SDB. METHODS: One hundred sixteen children (3-12 years) with SDB and 42 controls underwent overnight polysomnography including measurement of cerebral oxygenation. Power spectral analysis of the EEG derived from C4-M1 and F4-M1, quantified delta, theta, alpha, and beta waveforms during sleep. Multiple regression tested whether age, SDB severity, heart rate (HR), HR variability (HRV), and cerebral oxygenation were determinants of EEG spectral power. RESULTS: There were no differences in EEG spectral power derived from either central or frontal regions for any frequency between children with different severities of SDB so these were combined. Age, HR, and HRV low frequency power were significant determinants of EEG spectral power depending on brain region and sleep stage. CONCLUSION: The significant findings of this study were that age and autonomic control, rather than cerebral oxygenation and SDB severity, were predictive of EEG spectral power in children. Further research is needed to elucidate how the physiology that underlies the relationship between autonomic control and EEG impacts on the cardiovascular sequelae in children with SDB.

Being Born Too Small and Too Early May Alter Sleep in Childhood.

STUDY OBJECTIVES: Fetal growth restriction (FGR) occurs in up to 10% of pregnancies and is associated with increased risk of prematurity and neurodevelopmental impairment. FGR also alters sleep-state distribution in utero and maturation in infancy. Currently, limited data on the long-term associations of FGR and childhood sleep exist. Accordingly, we assessed the associations between preterm birth and FGR and sleep in children aged 5-12 years. METHODS: Seventeen children born preterm and FGR, 15 children born preterm but appropriately grown (appropriate birth weight for gestational age [AGA]), and 20 term AGA children (controls) were studied using overnight polysomnography. Sleep macroarchitecture was assessed using standard criteria, and sleep microarchitecture was assessed using spectral analysis of the electroencephalogram (C4-M1) with total, δ (0.5-3.9 Hz), θ (4.0-7.9Hz), α (8.0-11.9 Hz), σ (12.0-13.9 Hz), and ß power (14.0-30 Hz) calculated. RESULTS: For sleep macroarchitecture, preterm FGR children had higher N2% compared with term AGA children (p < .05). Preterm AGA children had reduced total sleep time, NREM%, and sleep efficiency compared with term AGA children (p < .05 for all). For sleep microarchitecture, preterm FGR children had a higher amount of total, δ and α power compared with both groups (p < .05). Sigma and ß power was lowest in the preterm AGA group compared with both groups (p < .05 for both). CONCLUSIONS: Prematurity and FGR were associated with altered sleep macro- and microarchitecture measures indicative of reduced sleep quantity and quality in childhood. As sleep disturbance can affect both behavior and neurodevelopment in children, sleep in FGR and preterm children warrants further investigation.

Overweight and obese children with sleep disordered breathing have elevated arterial stiffness.

BACKGROUND: The prevalence of obese children with sleep disordered breathing (SDB) is increasing. Obesity and SDB are independent cardiovascular risk factors, of which arterial stiffness is an early sign. Pulse wave velocity (PWV), is a marker of arterial stiffness and central systolic blood pressure (cSBP) is a better predictor of cardiovascular outcome than peripheral blood pressure. Therefore, we aimed to determine PWV and cSBP in overweight/obese or normal weight children with sleep disordered breathing (SDB), and non-snoring normal weight controls. METHODS: Children (3-18 y) with SDB (overweight/obese [BMI z-scores ≥ 1.04], n = 48; normal weight n = 44) referred for clinical assessment of SDB and normal weight non-snoring controls recruited from the community (n = 38) underwent overnight polysomnography. PWV was calculated using photoplethysmography. cSBP was calculated using applanation tonometry in a subset of children older than 8 y (n = 55) who had usable waveforms. RESULTS: Overweight/obese SDB group had higher PWV (mean cm/s (95% CI); wake: 366 (355-380); sleep: 340 (324-357)), than the normal-weight SDB group (wake: 257 (247-267), p = 0.002; sleep: 255 (242-269), p = 0.005), and non-snoring controls (wake: 238 (226-249), p = 0.002; sleep: 235 (220-250), p < 0.001). The normal-weight SDB group had higher PWV than controls (p = 0.03). Overweight/obese children with SDB had higher cSBP (105 (100-110) mmHg) compared with the normal weight children with SDB (96 (90-102)) and the non-snoring controls (97 (91-104); p < 0.05 for both). CONCLUSION: This study suggests that overweight/obesity substantially worsens the cardiovascular sequelae of SDB, highlighting the imperative to treat obesity and SDB in children early in order to reduce future cardiovascular disease risk.

The impact of sleep disordered breathing on cardiovascular health in overweight children.

BACKGROUND: Up to 50% of overweight/obese children have obstructive sleep apnea (OSA) compared to up to 6% of normal weight children. We compared cardiovascular variables between normal weight and overweight/obese children with and without OSA, and controls. METHODS: Seventy-four referred children and 24 normal weight non-snoring controls (8-18 years) were recruited. Referred children were grouped according to their obstructive apnea hypopnea index (OAHI): OSA (>1 event/h) or primary snoring (PS ≤ 1 event/h) and whether they were normal weight (BMI z-score <1.04) or overweight/obese (BMI z-score ≥ 1.04). Wake blood pressure (BP), heart rate (HR), and pulse transit time (PTT, an inverse continuous surrogate measure of blood pressure) during sleep were recorded. RESULTS: Wake BP was higher in the overweight/obese OSA group than in the control, normal weight PS, and overweight/obese PS groups (p < 0.05 for all). During sleep, BP, and HR were elevated in the overweight/obese OSA group compared to those in non-snoring controls (p < 0.05). More children who were overweight/obese had reduced BP and HR dipping from wake to sleep than normal weight children. The BMI z-score predicted HR and PTT when asleep and both age and BMI z-score predicted BP when awake. CONCLUSION: This study showed that BMI has both combined and independent effects on BP and HR in children with OSA. We have previously shown that treatment of OSA reduces BP and suggest that treatment of OSA in the growing number of overweight/obese children may improve cardiovascular outcomes.

Regional brain tissue changes and associations with disease severity in children with sleep-disordered breathing.

STUDY OBJECTIVES: Children with sleep-disordered breathing (SDB) exhibit behavioral, cognitive, and autonomic deficits, suggestive of neural injury. We assessed whether the tissue alterations resulted from acute or chronic processes, and whether alterations correlated with disease severity. METHODS: Brain tissue integrity was examined with mean diffusivity (MD) (3.0 T scanner) in 20 nonsnoring controls (mean age ± SEM, 12.2 ± 0.6 years; 10 males) and 18 children with SDB (12.3 ± 0.7 years; 11 males). Sleep, cognitive, and behavioral measures were compared between groups following overnight polysomnography using Student's t tests. Whole-brain MD maps were realigned and averaged, normalized, smoothed, and compared between groups using ANCOVA (covariates: age, gender, and socioeconomic status). Partial correlations were calculated between whole-brain smoothed MD maps and obstructive apnea-hypopnea indices (OAHIs). RESULTS: Age, gender, and sleep variables did not differ between groups. The SDB group showed higher OAHIs, body mass indices, and systolic blood pressure. Significantly reduced MD values (acute changes) appeared in the hippocampus, insula, thalamus, temporal and occipital cortices, and cerebellum, but were increased (chronic damage) in the frontal and prefrontal cortices in the SDB group over controls. Both positive and negative correlations appeared with extent of tissue changes and disease severity. Externalizing and Total Problem Behaviors were significantly higher in children with SDB. Verbal, performance, and total IQ scores trended lower, and behavioral scores trended higher. CONCLUSIONS: Pediatric SDB is accompanied by predominantly acute brain changes in areas that regulate autonomic, cognitive, and mood functions, and chronic changes in frontal cortices essential for behavioral control. Interventions need to be keyed to address acute vs chronic injury.

Back to sleep or not: the effect of the supine position on pediatric OSA: Sleeping position in children with OSA.

BACKGROUND: In both adults and children, obstructive sleep apnea (OSA) has significant adverse cardiovascular consequences. In adults, sleeping position has a marked effect on the severity of OSA; however, the limited number of studies conducted in children have reported conflicting findings. We aimed to evaluate the effect of sleeping position on OSA severity and the cardiovascular consequences in preschool-aged children. METHODS: This was a retrospective analysis of children (3-5 years of age) diagnosed with OSA (n = 75) and nonsnoring controls (n = 25). Sleeping position was classified as supine, semi-supine, left lateral, right lateral, prone, and semi-prone by using video recordings during one night of attended polysomnography. OSA severity and cardiovascular parameters were compared between the positions. RESULTS: All children spent significantly more sleep time in the supine position than in any other position. The obstructive apnea-hypopnea index was higher in the supine position than in the other sleeping positions during NREM (p < 0.05), higher in the moderate/severe OSA group when sleeping in the supine position than when sleeping in the left and right lateral positions (p < 0.05 for both) and prone position (p = 0.007) during REM. Sympathovagal balance was decreased in children with OSA in the supine and lateral positions (p < 0.05). CONCLUSIONS: This study identified that preschool-aged children, whether nonsnoring controls or children with OSA, predominately sleep in the supine position, and OSA was more severe in the supine position. We suggest that to avoid the supine sleep position, positional therapy has the potential to ameliorate OSA severity, and the known cardiovascular consequences.