Allergic disease, sleep problems, and psychological distress in children recruited from the general community.

BACKGROUND: It is not clear which allergic disease is most strongly related to which sleep problem and whether sleep problems may mediate the association between allergic disease and psychological distress. There is also a need for more community-based studies using nonreferred samples. OBJECTIVE: To evaluate the association between individual allergic diseases and sleep problems and test whether the association between allergic disease and psychological distress is mediated through sleep problems. METHODS: Parents of 1449 Australian children aged 6 to 10 years recruited from the general community, completed measures of sleep problems (Pediatric Sleep Survey Instrument), psychological distress (Strengths and Difficulties Questionnaire), and frequency of allergic diseases. RESULTS: Sleep and psychological distress scores were in the reference range. After controlling for coexisting allergic diseases, allergic rhinitis was associated with sleep routine problems, morning tiredness, night arousals, sleep disordered breathing and restless sleep; asthma with sleep routine problems, sleep disordered breathing and restless sleep; and eczema with restless sleep. Path analyses revealed that sleep problems mediated the association between asthma and allergic rhinitis but not eczema with psychological distress. CONCLUSION: In this nonreferred community sample, the frequency of sleep problems and psychological distress was lower than that typically reported in children referred to specialized centers. However, allergic rhinitis was associated with a broad range of sleep problems and to a lesser extent in children with asthma and least in children with eczema. Path analysis revealed that the association between allergic disease and psychological distress was mediated through sleep problems, highlighting the importance of assessing sleep health in children with allergic disease.

Utilisation of machine learning to predict surgical candidates for the treatment of childhood upper airway obstruction.

OBJECTIVE: To investigate the effect of adenotonsillectomy on OSAS symptoms based on a data-driven approach and thereby identify criteria that may help avoid unnecessary surgery in children with OSAS. METHODS: In 323 children enrolled in the Childhood Adenotonsillectomy Trial, randomised to undergo either early adenotonsillectomy (eAT; N = 165) or a strategy of watchful waiting with supportive care (WWSC; N = 158), the apnea-hypopnea index, heart period pattern dynamics, and thoraco-abdominal asynchrony measurements from overnight polysomnography (PSG) were measured. Using machine learning, all children were classified into one of two different clusters based on those features. The cluster transitions between follow-up and baseline PSG were investigated for each to predict those children who recovered spontaneously, following surgery and those who did not benefit from surgery. RESULTS: The two clusters showed significant differences in OSAS symptoms, where children assigned in cluster A had fewer physiological and neurophysiological symptoms than cluster B. Whilst the majority of children were assigned to cluster A, those children who underwent surgery were more likely to stay in cluster A after seven months. Those children who were in cluster B at baseline PSG were more likely to have their symptoms reversed via surgery. Children who were assigned to cluster B at both baseline and 7 months after surgery had significantly higher end-tidal carbon dioxide at baseline. Children who spontaneously changed from cluster B to A presented highly problematic ratings in behaviour and emotional regulation at baseline. CONCLUSIONS: Data-driven analysis demonstrated that AT helps to reverse and to prevent the worsening of the pathophysiological symptoms in children with OSAS. Multiple pathophysiological markers used with machine learning can capture more comprehensive information on childhood OSAS. Children with mild physiological and neurophysiological symptoms could avoid AT, and children who have UAO symptoms post AT may have sleep-related hypoventilation disease which requires further investigation. Furthermore, the findings may help surgeons more accurately predict children on whom they should perform AT.

Increased Platelet Aggregation in Children and Adolescents with Sleep-disordered Breathing.

Rationale: Sleep-disordered breathing (SDB) is associated with increased vascular resistance in children and adults. Persistent increased vascular resistance damages vascular endothelial cells-a marker of which is increased platelet activation.Objectives: This study compared whole-blood impedance platelet aggregation in children with clinically diagnosed SDB warranting adenotonsillectomy and healthy control subjects.Methods: Thirty children who had SDB warranting intervention clinically diagnosed by experienced pediatric otolaryngologists were recruited from adenotonsillectomy waitlists, and 20 healthy children from the community underwent overnight polysomnography to determine SDB severity (obstructive apnea-hypopnea index). Snoring frequency was collected from parents. In the morning, a fasting blood sample was taken, and whole-blood platelet aggregation was measured.Measurements and Main Results: Children with SDB exhibited increased platelet aggregation to TRAP (thrombin receptor-activating peptide) (children with SDB = 114.8 aggregation units [AU] vs. control subjects = 98.0 AU; P < 0.05) and COL antibody (96.7 vs. 82.2 AU; P < 0.05) and an increased trend in ADP antibody (82.3 vs. 69.2 AU; P < 0.07) but not aspirin dialuminate (82.1 vs. 79.5 AU; P > 0.05). No significant association was observed between either the obstructive apnea-hypopnea index and any aggregation parameter, but parental report of snoring was positively associated with TRAP aggregation (Kendall's τ-c = 0.23; P < 0.05).Conclusions: The finding of increased platelet aggregation is consistent with endothelial damage. This suggests that the profile of cardiovascular changes noted in adults with SDB may also occur in children with SDB.

Ascending aortic blood flow velocity is increased in children with primary snoring/mild sleep-disordered breathing and associated with an increase in CD8 + T cells expressing TNFα and IFNγ.

Sleep-disordered breathing (SDB) is associated with cardiovascular disease and systemic inflammation in adults but this remains to be explored in children, especially in children with the most common form of SDB, i.e. primary snoring/mild SDB. This pilot study investigated the relationship between the cardiovascular function and inflammation in children with mild SDB. Nineteen participants aged 5-14 years underwent overnight polysomnography, cardiac magnetic resonance imaging (aortic blood flow velocity and left and right ventricular systolic function) and assessment for inflammatory markers (intracellular cytokine analysis of T cells by flow cytometry). Parents also completed the Sleep Disturbances Scale for Children (SDSC). Children with mild SDB exhibited increased ascending aortic peak systolic velocity compared to controls (SDB 119.95 m/s vs. control 101.49 m/s, p < 0.05). No significant group differences were observed for left and right ventricular ejection fraction or mean aortic blood flow velocity from either the ascending aorta or pulmonary artery. Children with mild SDB had increased inflammatory markers as demonstrated by elevated T cell interferon gamma (IFNγ) (SDB 52 ± 4% vs. control 25 ± 3% positive cells, p < 0.005) and tumour necrosis factor alpha (TNFα) (SDB 39 ± 4% vs. control 20 ± 2% positive cells, p < 0.005) expression from CD8+ cells. A strong positive correlation was observed between ascending aorta peak blood flow velocity and both TNFα and IFNγ (TNFα, r = 0.54, p < 0.03; IFNγ, r = 0.63, p < 0.005, respectively). Polysomnography revealed that oxygen saturation (SaO2) nadir was significantly lower in children with mild SDB compared to controls (SDB 92.3 ± 2.7% vs. control 94.4 ± 1.6%, p < 0.05). A lower SaO2 nadir was associated with an increased ascending aorta peak systolic velocity (r = - 0.48, p < 0.05). As well, both a lower SaO2 nadir and an increased ascending aorta peak systolic velocity were associated with higher SDSC Sleep-Disordered Breathing and Disorder of Initiating and Maintaining Sleep subscale scores but not the polysomnographic-derived Obstructive Apnea-Hypopnea Index. The finding of elevated ascending aortic peak systolic blood flow velocity and its association with increased inflammatory markers suggests that the profile of cardiovascular changes noted in adult SDB may also occur in children with mild SDB.

Adenotonsillectomy for childhood obstructive sleep apnoea reduces thoraco-abdominal asynchrony but spontaneous apnoea-hypopnoea index normalisation does not.

The efficacy of adenotonsillectomy for treating obstructive sleep apnoea syndrome (OSAS) in children has been established, but its precise effects on inspiratory effort are not well documented.In 353 children enrolled in the Childhood Adenotonsillectomy Trial, randomised to undergo either early adenotonsillectomy (n=182) or a strategy of watchful waiting with supportive care (WWSC) (n=171), thoraco-abdominal asynchrony (TAA) was analysed during quiet, non-apnoeic and non-hypopnoeic breathing during sleep at baseline and at 7 months using overnight polysomnography.Children who underwent early adenotonsillectomy demonstrated a reduction in TAA post-surgery while the WWSC arm showed no change. On assessing TAA with regard to normalisation of clinical polysomnography findings at follow-up, TAA was reduced in children who had surgical resolution of OSAS (based on apnoea-hypopnoea index), but not in children who displayed spontaneous normalisation of apnoea-hypopnoea index. In the latter group, TAA was inversely correlated with quality of life.We conclude that adenotonsillectomy reduces TAA during quiet sleep. Monitoring of instantaneous TAA may yield additional insight in the dynamic changes of inspiratory effort. In combination with traditional indices of obstruction, TAA may more accurately characterise the degree of sleep-disordered breathing in children.

Flow-mediated dilatation, using time course data, shows maturation of the brachial artery from young children to mid-adolescents.

Flow-mediated dilatation (FMD) is a tool widely used to measure arterial responsiveness to sheer stress. However, there is scant literature to show how the peripheral arterial response changes as the vascular system matures. One reason for this is that the feasibility of measuring FMD in younger children has not been established. The aim of the present study was to assess brachial artery function at rest and during the FMD response after 4 min ischaemia of the forearm in children aged 6-15 years. Time to reach maximum FMD (FMDmax ) was found to be correlated with age (r = 0.4, P < 0.05), resting brachial artery diameter (r = 0.4, P < 0.05), height (r = 0.4, P < 0.05), body mass index (BMI; r = 0.45, P < 0.05), body surface area (r = 0.44, P < 0.05) and resting blood flow (r = 0.37, P < 0.05). However, there was no correlation between the traditional FMD response at 60 s or FMD maximal dilation and age, resting brachial artery diameter, height, weight, BMI, body surface area and resting blood flow. In conclusion, the time taken to reach the maximal dilation response is related to age, brachial artery luminal diameter and body habitus, but not the traditional measure of FMD response at 60 s or the maximal dilatation percentage.

Heartbeat evoked potentials during sleep and daytime behavior in children with sleep-disordered breathing.

RATIONALE: Event-related brain potentials allow probing of cortical information processing, but when evoked with externally induced stimuli may disrupt sleep homeostasis and do not provide insight into intrinsic cortical information processing. To investigate if cortical processing of intrinsic information in children with sleep-disordered breathing (SDB) is different from healthy children and, if so, whether it resolves with treatment, we used heartbeat as a source of interoceptive event-related brain potentials. OBJECTIVES: To investigate heartbeat evoked potentials (HEP) during sleep in healthy children and in children with SDB before and after treatment and to explore if there are any associations between HEP and daytime behavioral deficits in children with SDB. METHODS: Heartbeat-aligned EEG was assessed for presence of HEP within stage 2, slow-wave sleep, and REM sleep in 40 children with primarily mild to moderate SDB before and after adenotonsillectomy and in 40 matched control subjects at similar time points. MEASUREMENTS AND MAIN RESULTS: In both groups, nonrandom HEP were present in all sleep stages analyzed; however, amplitude of HEP were significantly lower in children with SDB during non-REM sleep (stage 2: P = 0.03; slow-wave sleep: P = 0.001). This between-group difference was not significant post adenotonsillectomy. Significant negative associations between HEP and daytime behavioral scores were observed at baseline. CONCLUSIONS: Children with SDB displayed reduced HEP amplitude during sleep, which might be indicative of changes in afferent sensory inputs to the brain and/or signify differences in sensory gating of cardiac-related information in the insular cortex. Adenotonsillectomy appears to reverse this effect.

Increased thoracoabdominal asynchrony during breathing periods free of discretely scored obstructive events in children with upper airway obstruction.

OBJECTIVE: This study aims to investigate the impact of upper airway obstruction (UAO) in children by measuring thoracoabdominal asynchrony (TAA) during periods of sleep apnea/hypopnea and during scored-event-free (SEF) breathing periods. METHODS: Respiratory inductive plethysmographic signals were extracted from polysomnographic data, recorded before and after adenotonsillectomy in 40 children with UAO and 40 healthy, matched children at equivalent time points. Thoracoabdominal asynchrony was computed using a Hilbert transform-based phase difference estimation method in SEF periods during stage 2, stage 4 non-rapid eye movement (NREM), and rapid eye movement (REM) sleep and compared between the groups. RESULTS: At baseline, in the UAO group, TAA during obstructions were significantly higher than TAA during SEF periods in both stage 2 and REM sleep. Compared to controls, children with UAO had a significantly higher TAA during SEF periods in stage 2, stage 4 sleep, and REM sleep. This between-group difference was not significant post adenotonsillectomy. UAO group showed a significant decrease in TAA compared to their baseline during SEF stage 2 and 4 NREM, but not in REM. CONCLUSION: Upper airway obstruction in children is associated with increased TAA during SEF periods, indicative of continuous partial obstruction of the upper airway. Adenotonsillectomy decreased this effect significantly in non-REM sleep as evidenced by reduced asynchrony levels post-surgery. TAA assessment during sleep may therefore provide additional diagnostic information.

Teaching and learning in biophotonics: Crossing the bridge between educators and students.

As a rapidly growing field, biophotonics demonstrates an increasingly higher demand for interdisciplinary professionals and requires the implementation of a structured approach to educational and outreach activities focused on appropriate curriculum, and teaching and learning for audiences with diverse technical backgrounds and learning styles. Our study shows the main findings upon applying this approach to biophotonics workshops delivered 2 consecutive years while updating and improving learning outcomes, teaching strategies, workshop content based on student and teacher feedback. We provided resources for a variety of lecture-based, experimental, computer simulation activities. Quality of subject matter, teaching, and overall learning was rated as "Very good" or "Good" by 88%, 76%, and 82% of students in average, respectively. Application of our teaching strategies and materials during short- and long-term workshops/courses could potentially increase the interest in pursuing careers in the biophotonics field and related areas, leading to standardized approaches in designing education and outreach events across centers.

Respiratory sinus arrhythmia during sleep in children with upper airway obstruction.

Upper airway obstruction during adulthood is associated with cardiovascular morbidity; cardiovascular consequences of childhood upper airway obstruction are less well established. This study aimed at investigating the effect of childhood upper airway obstruction on respiratory sinus arrhythmia as a measure of cardiac vagal modulation during night-time sleep. Overnight polysomnography was conducted in 40 healthy children (20 M; age: 7.5 ± 2.6 years; body mass index percentile: 60.7 ± 26.4%) and 40 children with upper airway obstruction (24 M; age: 7.5 ± 2.7 years; body mass index percentile: 65.8 ± 31.9%). We used the phase-averaging technique to compute respiratory sinus arrhythmia amplitude and phase delay. To study sleep stage effects and the effect of upper airway obstruction, respiratory sinus arrhythmia was measured during all artefact-free sleep episodes, and after exclusion of respiratory events. A significant increase in respiratory sinus arrhythmia amplitude and phase delay was observed during stage 4 sleep as compared with rapid eye movement sleep in both groups (amplitude: controls = 0.10 ± 0.03 versus 0.07 ± 0.02 s, P < 0.01, respectively, and upper airway obstruction = 0.07 ± 0.03 versus 0.05 ± 0.03 s, P < 0.05, respectively; phase delay: controls = 3.1 ± 0.1 versus 3.0 ± 0.1 rad, P < 0.05, respectively, and upper airway obstruction = 3.13 ± 0.04 versus 3.04 ± 0.08 rad, P < 0.01, respectively). A significant association between respiratory sinus arrhythmia and apnea/hypopnea index was observed during stage 2 sleep in children with upper airway obstruction. Compared with healthy controls, a significant decrease in respiratory sinus arrhythmia amplitude during stage 2 sleep was observed in children with upper airway obstruction (0.09 ± 0.03 versus 0.06 ± 0.03 s, P < 0.05). However, this difference was not apparent when respiratory events were excluded from analysis. Importantly, respiratory sinus arrhythmia showed a strong negative correlation with body mass index. In conclusion, night-time respiratory sinus arrhythmia in children is sleep stage dependent and normal during quiet sleep in children with relatively mild upper airway obstruction.

Craniofacial and upper airway morphology in pediatric sleep-disordered breathing and changes in quality of life with rapid maxillary expansion.

INTRODUCTION: The association between pediatric sleep-disordered breathing caused by upper airway obstruction and craniofacial morphology is poorly understood and contradictory. The aims of this study were to evaluate the prevalence of children at risk for sleep-disordered breathing, as identified in an orthodontic setting by validated screening questionnaires, and to examine associations with their craniofacial and upper airway morphologies. A further aim was to assess the change in quality of life related to sleep-disordered breathing for affected children undergoing rapid maxillary expansion to correct a palatal crossbite or widen a narrow maxilla. METHODS: A prospective case-control study with children between 8 and 17 years of age (n = 81) at an orthodontic clinic was undertaken. The subjects were grouped as high risk or low risk for sleep-disordered breathing based on the scores from a validated 22-item Pediatric Sleep Questionnaire and the Obstructive Sleep Apnea-18 Quality of Life Questionnaire. Variables pertaining to a screening clinical examination, cephalometric assessment, and dental cast analysis were tested for differences between the 2 groups at baseline. Ten children who underwent rapid maxillary expansion were followed longitudinally until removal of the appliance approximately 9 months later with a repeated Obstructive Sleep Apnea-18 Quality of Life Questionnaire. All data were collected blinded to the questionnaire results. RESULTS: The frequency of palatal crossbite involving at least 3 teeth was significantly higher in the high-risk group at 68.2%, compared with the low-risk group at 23.2% (P <0.0001). Average quality of life scores in the high-risk group indicated reduced quality of life related to sleep-disordered breathing by 16% compared with children in the low-risk group at baseline (P <0.0001). Cephalometrically, mean inferior airway space, posterior nasal spine to adenoidal mass distance, and adenoidal mass to soft palate distance were reduced in the high-risk group compared with the low-risk group by 1.87 mm (P <0.03), 2.82 mm (P <0.04), and 2.13 mm (P <0.03), respectively. The mean maxillary intercanine, maxillary interfirst premolar, maxillary interfirst molar, mandibular intercanine, and mandibular interfirst premolar widths were reduced in the high-risk group compared with the low-risk group by 4.22 mm (P <0.0001), 3.92 mm (P <0.0001), 4.24 mm (P <0.0001), 1.50 mm (P <0.01), and 1.84 mm (P <0.01), respectively. Children treated with rapid maxillary expansion showed an average improvement of 14% in quality of life scores in the high-risk group compared with the low-risk group, which showed a slight worsening in quality of life related to sleep-disordered breathing by an average of 1% (P <0.04), normalizing the quality of life scores in the high-risk children to the baseline scores compared with the low-risk group. CONCLUSIONS: Children at high risk for sleep-disordered breathing are characterized by reduced quality of life, reduced nasopharyngeal and oropharyngeal sagittal dimensions, palatal crossbite, and reduced dentoalveolar transverse widths in the maxillary and mandibular arches. No sagittal or vertical craniofacial skeletal cephalometric predictors were identified for children at high risk for sleep-disordered breathing. In the short term, rapid maxillary expansion might aid in improvement of the quality of life for children with a narrow maxilla in the milder end of the sleep-disordered breathing spectrum.

Paediatric sleep-disordered breathing due to upper airway obstruction in the orthodontic setting: a review.

The essential feature of paediatric sleep-disordered breathing (SDB) is increased upper airway resistance during sleep presenting clinically as snoring. Paediatric SDB is a continuum ranging from primary snoring (PS), which is not associated with gas exchange abnormalities or significant sleep fragmentation, to obstructive sleep apnoea (OSA) with complete upper airway obstruction, hypoxaemia, and obstructive hypoventilation. Adenotonsillar hypertrophy, obesity and craniofacial disharmonies are important predisposing factors in the development and progression of paediatric SDB. Clinical symptoms are significant and domains affected include behaviour, neurocognition, cardiovascular morbidity and quality of life. Overnight polysomnography is the current diagnostic gold standard method to assess SDB severity while adenotonsillectomy is the recommended first line of treatment. Other treatments for managing paediatric SDB include nasal continuous airway pressure, the administration of nasal steroids, dentofacial orthopaedic treatment and surgery. However, there are insufficient long-term efficacy data using dentofacial orthopaedics to treat paediatric SDB. Further studies are warranted to define the characteristics of patients who may benefit most from orthodontic treatment.

Short report: Sleep talking and mental health in children with developmental problems and typically developing children.

BACKGROUND: Sleep talking although often considered benign is associated with poor mental health. However, it remains to be tested whether this association may be better explained by the presence of co-morbid sleep problems and the presence in survey samples of children with development disorders who tend to report a higher frequency of both sleep problems and poor mental health. AIM: The aim of the present study was to examine the association between sleep talking and mental health after controlling for comorbid sleep problems in typically developing children and children with developmental problems. METHODS: Parents of typically developing children (n = 1609) and children with either intellectual or developmental delay (n = 128) aged 5-10 years completed an omnibus survey which was administered through participating South Australian primary schools assessing mental health (Strengths and Difficulties Questionnaire) and sleep problems (Paediatric Sleep Survey Instrument). RESULTS: After controlling for co-morbid sleep problems, regression analyses revealed that sleep talking in typically developing children was an independent but weak predictor of worse emotional symptoms, conduct problems and peer relationship problems. By contrast, only a single significant association was observed in children with developmental problems. Paradoxically, sleep talking was associated with better prosocial behaviour. CONCLUSION: It is suggested that in typically developing children with a history of sleep talking, mental health merits evaluation at clinical interview while in both typically developing children and children with developmental problems, co-morbid sleep problems merit evaluation.

Quality-of-life but not behavior improves 48-months post-adenotonsillectomy in children with SDB.

BACKGROUND: Long term follow-up studies (>12 mths) of changes in behavior and quality-of-life (QoL) in children with sleep disordered breathing (SDB) post-adenotonsillectomy are limited and there is a lack of consensus in the reported findings. The aim of this study was to evaluate children's sleep, QoL and behavior at baseline and 6 mths and 48 mths post-adenotonsillectomy for clinically diagnosed SDB. METHODS: This prospective longitudinal study of children aged 3-12 y recruited from a Children's Hospital otolaryngology clinic compared polysomnographic parameters, behavior (Child Behavior Checklist; CBCL) and QoL (OSA-18) at baseline, 6mths and 48mths post-adenotonsillectomy and compared these parameters to healthy non-snoring controls recruited from the general community at the same time points. RESULTS: Sixty-four children completed sleep, behavior and QoL assessments (SDB = 20M/9F, Controls = 18M/17F) at all three time points. Sleep and ventilatory parameters significantly improved in children with SDB with minimal residual obstruction evident at 48 mths post-adenotonsillectomy. Compared to baseline, OSA-18 scores significantly improved post-adenotonsillectomy in children with SDB and were equivalent to the scores of controls at 6 mths and 48 mths post-AT. No significant improvement was observed in behavior in children with SDB post-adenotonsillectomy over the same time period. CONCLUSION: Baseline deficits in sleep and QoL in children with SDB were normalized at 6 mths post-adenotonsillectomy and gains were maintained at 48 mths post-adenotonsillectomy. Children with SDB did not show significant gains in behavior either at 6 mths or 48 mths post-adenotonsillectomy.

Cardiorespiratory response to spontaneous cortical arousals during stage 2 and rapid eye movement sleep in healthy children.

Arousal from sleep is associated with transient and abrupt cardiorespiratory changes, and elevated arousals associated with sleep disorders may trigger adverse cardiovascular sequela. In this paper, we provide the first data in children on cardiorespiratory responses to cortical arousal. Heart rate and ventilatory responses to arousal from stage 2 and rapid eye movement (REM) sleep were investigated in 40 normal, healthy Caucasian children (age: 7.7 +/- 2.6 years; body mass index z-score: 0.30 +/- 0.8). All children underwent overnight polysomnography studies. Cortical arousals were scored according to standard criteria. Heart rate changes were assessed over 30 s, starting 15 s prior to cortical arousal onset. Breathing rates were quantified three breaths before and after arousal onset. Arousals from stage 2 as well as REM sleep resulted in an R-R interval shortening of about 15%, independent of age and gender. The R-R interval shortening initiated at least 3 s before the cortical arousal onset. The breathing interval immediately after cortical arousal onset was significantly shortened (P < 0.001). In conclusion, cortical arousals in children are associated with an increase in breathing rate and significant heart rate accelerations, which typically precede the cortical arousal onset.

The Inconsistent Nature of Heart Rate Variability During Sleep in Normal Children and Adolescents.

Introduction: Cardiac function is modulated by multiple factors including exogenous (circadian rhythm) and endogenous (ultradian 90-110 min sleep cycle) factors. By evaluating heart rate variability (HRV) during sleep, we will better understand their influence on cardiac activity. The aim of this study was to evaluate HRV in the dark phase of the circadian rhythm during sleep in healthy children and adolescents. Methods: One 3 min segment of pre-sleep electrocardiography (EEG) and 3, 6 min segments of electrocardiography recorded during polysomnography from 75 healthy children and adolescents were sampled during progressive cycles of slow wave sleep (SWS1, SWS2, SWS3). Three, 3 min segments of rapid eye movement sleep (REM) were also assessed, with REM1 marked at the last REM period before awakening. Studies that recorded REM3 prior to SWS3 were used for assessment. HRV variables include the following time domain values: mean NN (average RR intervals over given time), SDNN (Standard Deviation of RR intervals), and RMSSD (root Mean Square of beat-to-beat Differences). Frequency domain values include: low frequency (LF), high frequency (HF), and LF:HF. Results: Mixed linear effects model analysis revealed a significant difference in time and frequency domain values between sleep cycles and stages. Mean NN was lowest (highest heart rate) during pre-sleep then significantly increased across SWS1-3. Mean NN in SWS1 was similar to all REM periods which was significantly lower than both SWS2 and SWS3. SDNN remained at pre-sleep levels until SWS3, and then significantly increased in REM1&2. There was a large drop in LF from pre-sleep to SWS1. As cycles progressed through the night, LF remains lower than awake but increases to awake like levels by REM2. RMSSD and HF were lowest in pre-sleep and increased significantly by SWS1 and remain high and stable across stages and cycles except during the REM3 period where RMSSD decreased. Conclusion: Our results demonstrate that there are considerable changes in the spectral analysis of cardiac function occurring during different sleep stages and between sleep cycles across the night. Hence, time of night and sleep stage need to be considered when reporting any HRV differences.

The microbial abundance dynamics of the paediatric oral cavity before and after sleep.

Objective: Microhabitats in the oral cavity differ in microbial taxonomy. However, abundance variations of bacterial and viral communities within these microhabitats are not fully understood. Aims and Hypothesis: To assess the spatial distribution and dynamics of the microbial abundances within 6 microhabitats of the oral cavity before and after sleep. We hypothesise that the abundance distributions of these microbial communities will differ among oral sites. Methods: Using flow cytometry, bacterial and virus-like particle (VLP) abundances were enumerated for 6 oral microhabitats before and after sleep in 10 healthy paediatric sleepers. Results: Bacterial counts ranged from 7.2 ± 2.8 × 105 at the palate before sleep to 1.3 ± 0.2 × 108 at the back of the tongue after sleep, a difference of 187 times. VLPs ranged from 1.9 ± 1.0 × 106 at the palate before sleep to 9.2 ± 5.0 × 107 at the back of the tongue after sleep, a difference of 48 times. Conclusion: The oral cavity is a dynamic numerically heterogeneous environment where microbial communities can increase by a count of 100 million during sleep. Quantification of the paediatric oral microbiome complements taxonomic diversity information to show how biomass varies and shifts in space and time.

The sensitivity of a PDA-based psychomotor vigilance task to sleep restriction in 10-year-old girls.

The impact of sleep restriction on sustained attention in children has not been well quantified. To address this shortcoming, this study tested the sensitivity of a 5-min personal digital assistant-psychomotor vigilance task (PDA-PVT) to sleep restriction in 14 female children [mean (SD) age = 10.6 +/- 0.3 years]. The children underwent PDA-PVT trials at regular intervals both before and after a sleep restriction (5 h time-in-bed) and a control (10 h time-in-bed) condition. Sleep restriction was associated with longer mean response times and increased number of lapses. These results are consistent with findings in the adult literature suggesting an association between inadequate sleep and impaired functioning. In conclusion, the 5-min PDA-PVT is sensitive to sleep restriction in pre-adolescent female children supporting the utility of the PDA-PVT for examining the impact of sleep deprivation on daytime functioning in children.

Differences in dentofacial morphology in children with sleep disordered breathing are detected with routine orthodontic records.

BACKGROUND: Residual snoring in children with obstructive sleep disordered breathing (SDB) may continue post-adenotonsillectomy. This study aims to identify baseline dentofacial differences in children with SDB using routine orthodontic records that might aid effective early intervention for the upper airway to prevent continued obstruction. METHODS: Children (6-16 years) with clinically diagnosed SDB from a paediatric Otolaryngology Clinic who required adenotonsillectomy were participants (n = 10). The control group (n = 9) comprised healthy non-snoring children from the community. Baseline overnight polysomnography (PSG), standardised frontal and right profile photographs and alginate impressions were taken of all children. Facial width, length, depth, convexity and mandibular position were measured from the photographs. The occlusion, arch width, arch depth, maxillary arch form, palatal height and volume were recorded from digitised dental models. Inter-group differences were compared. RESULTS: SDB patients had a significantly increased lower face height, maxillo-mandibular angle (1.73°; 95% CI 0.45-3.0) and a narrower maxillary arch in the upper posterior region. There was a trend towards a decreased palatal volume, increased posterior crossbite and Class II molar relationship. CONCLUSION: Dentofacial phenotypic differences between children with SDB and controls can be detected using facial photographs and dental models. Increased awareness of these features may help to identify children who to continue to snore post adenotonsillectomy.

Effect of adenotonsillectomy for childhood obstructive sleep apnea on nocturnal heart rate patterns.

Study Objectives: To assess the effect of adenotonsillectomy for relieving obstructive sleep apnea syndrome (OSAS) symptoms in children on cardiac autonomic modulation. Methods: In 354 children enrolled in the Childhood Adenotonsillectomy Trial, randomized to undergo either early adenotonsillectomy (eAT; N = 181) or a strategy of watchful waiting with supportive care (WWSC; N = 173), nocturnal heart rate control was analyzed during quiet, event-free sleep at baseline and at 7 months using overnight polysomnography (PSG). The relative frequency of patterns indicating monotonous changes in heart rate was quantified. Results: Children who underwent eAT demonstrated a significantly greater reduction in heart rate patterns postsurgery than the WWSC group. On assessing those heart rate patterns regarding normalization of clinical PSG, heart patterns were reduced to a similar level in both groups. In children whose AHI normalized spontaneously, heart rate patterns were already significantly less frequent at baseline, suggesting that upper airway obstruction was milder in this group at the outset. Conclusions: Adenotonsillectomy reduces monotonous heart rate patterns throughout quiet event-free sleep, reflecting a reduction in cardiac autonomic modulation. Heart rate pattern analysis may help quantifying the effect of OSAS on autonomic nervous system activity in children. Clinical Trial Registration: The study was registered at Clinicaltrials.gov (#NCT00560859).