Acoustics of snoring and automatic snore sound detection in children.

OBJECTIVE: Acoustic analyses of snoring sounds have been used to objectively assess snoring and applied in various clinical problems for adult patients. Such studies require highly automatized tools to analyze the sound recordings of the whole night's sleep, in order to extract clinically relevant snore- related statistics. The existing techniques and software used for adults are not efficiently applicable to snoring sounds in children, basically because of different acoustic signal properties. In this paper, we present a broad range of acoustic characteristics of snoring sounds in children (N = 38) in comparison to adult (N = 30) patients. APPROACH: Acoustic characteristics of the signals were calculated, including frequency domain representations, spectrogram-based characteristics, spectral envelope analysis, formant structures and loudness of the snoring sounds. MAIN RESULTS: We observed significant differences in spectral features, formant structures and loudness of the snoring signals of children compared to adults that may arise from the diversity of the upper airway anatomy as the principal determinant of the snore sound generation mechanism. Furthermore, based on the specific audio features of snoring children, we proposed a novel algorithm for the automatic detection of snoring sounds from ambient acoustic data specifically in a pediatric population. The respiratory sounds were recorded using a pair of microphones and a multi-channel data acquisition system simultaneously with full-night polysomnography during sleep. Brief sound chunks of 0.5 s were classified as either belonging to a snoring event or not with a multi-layer perceptron, which was trained in a supervised fashion using stochastic gradient descent on a large hand-labeled dataset using frequency domain features. SIGNIFICANCE: The method proposed here has been used to extract snore-related statistics that can be calculated from the detected snore episodes for the whole night's sleep, including number of snore episodes (total snoring time), ratio of snore to whole sleep time, variation of snoring rate, regularity of snoring episodes in time and amplitude and snore loudness. These statistics will ultimately serve as a clinical tool providing information for the objective evaluation of snoring for several clinical applications.

[A Randomized Controlled Trial on the Effect of Earmuffs on Intermittent Hypoxia and Bradycardia in Preterm Infants]. / Lärm auf der Neugeborenen-Intensivstation: randomisierte Studie zum Einfluss eines Gehörschutzes auf intermittierende Hypoxien und Bradykardien.

BACKGROUND: Irregular breathing causing hypoxia and bradycardia is a common problem of preterm infants but its pathophysiology is incompletely understood. Agitation provoked by environmental noise may play a role. We wanted to know if earmuffs can at least halve the rate of intermittent hypoxia in premies. PATIENTS AND METHODS: In this randomized controlled trial 31 infants (14 male; median [min.-max.] birth weight and gestational age: 1 323 g [560-1 990] and 30(1/7) weeks [25(5/7)-33(0/7)]) had the effect of earmuffs on the frequency of pulse oximeter desaturations (SpO(2) <80%) and bradycardia events (<80 beats per minute) tested, documented via a standard home monitor. Infants were measured 2 h each with or without earmuffs; the sequence of intervention was randomised. Measurement conditions were kept constant while a noise meter recorded sound pressure levels at a 1 Hz sampling rate. RESULTS: Median sound pressure level was 46.8 dB(A). In a pre-study, ear muffs yielded a sound reduction by 7.2 dB. 19 infants had a total of 474 desaturations. The median (25.-75. percentile) number of desaturations was 1 (1-10.5) without, and 1 (1-10) with earmuffs. The amount of infants with at least one desaturation was equal in both treatment protocols. Only 7 bradycardias occurred. CONCLUSION: The earmuffs had, in a rather quiet environment, no effect on intermittent hypoxia in these infants.

[Snoring in children. Algorithm for diagnostic approach]. / Schnarchen bei Kindern. Algorithmus zum diagnostischen Vorgehen.

BACKGROUND: Snoring in children is a prevalent symptom and may be an indicator of obstructive sleep apnoea. Despite its importance, there is no national guideline on its appropriate management. OBJECTIVE: To provide recommendations for the management of snoring in children and adolescents treated in a primary care setting. METHODS: A total of 16 national paediatric sleep experts were included in a Delphi process and formulated recommendations in the form of a step-wise work-up procedure. RESULTS: The following 8 steps were developed: (1) Identification of true cases of habitual snoring. (2) Identification of high-risk patients who should undergo polysomnography in a sleep laboratory. (3) Identification of mild cases that may be treated with anti-inflammatory medication. (4) Identification of cases that should be referred to an otorhinolaryngologist for potential surgery. (5) Performance of polysomnography in cases that remain unclear despite steps 3 and 4 to rule out obstructive sleep apnoea. (6) Reconsideration of surgery in cases with moderate to severe obstructive sleep apnoea. (7) Identification of severe sleep apnoea cases requiring continuous positive airway pressure therapy. (8) Identification of cases suitable for orthodontic treatment, craniofacial surgery or speech therapy. CONCLUSION: This guideline should help to improve the management of snoring children and adolescents in Germany.

[Medicinal treatment of breathing disorders in adenotonsillar hyperplasia]. / Medikamentöse Behandlung von Atmungsstörungen bei adenotonsillärer Hyperplasie.

BACKGROUND: Adenotonsillar hyperplasia (ATH) can lead to severe breathing disorders, such as impaired nasal breathing, mouth breathing, snoring and obstructive sleep apnea. In such cases ATH should be treated mostly by performing adenoidectomy and/or adenotonsillectomy. There is increasing evidence that anti-inflammatory medication (AIM) is effective in treating ATH-related breathing disorders. OBJECTIVES: The aim of this study was to provide evidence and recommendations for the use of AIM in the treatment of ATH-related breathing disorders. METHODS: In this study 12 national pediatric sleep experts were included into a Delphi process and formulated indications and recommendations. RESULTS: The use of AIM in the treatment of ATH-related breathing disorders is sufficiently supported by the results of randomized controlled trials and systematic reviews. Nasal beclometason and nasal mometason have been studied for the treatment of enlarged adenoids and nasal fluticason and oral montelukast for the treatment of obstructive sleep apnea. The use of AIM for first-line treatment should be restricted to selected indications, such as a characteristic patient age and exclusion of an acute upper respiratory tract infection. Evidence-based recommendations are given concerning indications, dosage, treatment duration and correct administration of AIM. CONCLUSIONS: Anti-inflammatory medications are simple and effective alternatives for the treatment of ATH-related breathing disorders. These guidelines are intended to promote the use of AIM by pediatricians in ambulatory care settings.

The association between childhood overweight and obesity and otitis media.

OBJECTIVE: The objective of this study was to examine the association between otitis media and childhood obesity in a population-based sample of elementary school children in the Canadian province of Nova Scotia. METHODS: The study design is a prospective cohort study, linking data from a population-based survey of Grade 5 students (aged 10-11 years) in the Canadian province of Nova Scotia in 2003 with Nova Scotia administrative health data. Measured body mass index was used to define weight status based on the age- and gender-specific cut-off points of the International Obesity Task Force. Health administration data for each child was linked via Health Card numbers. The primary outcome was healthcare utilization (physician visits and costs) for suppurative otitis media (International Classification of Diseases [ICD]9: 382; ICD10: H65-66) with no previous diagnosis of otitis in the last 30 days. RESULTS: Relative to normal weight children, obese children had more healthcare provider contacts for otitis media (adjusted incidence rate ratio 2.03, 95% confidence interval [CI] 1.66-2.49), incurred more costs per otitis media-related visit ($47 vs. $24, P = 0.0001) and had higher odds to have repeated otitis media (adjusted odds ratio 2.27, 95% CI 1.54-3.35). Socioeconomic factors, a history of breastfeeding, presence of an allergic disorder or chronic adenoid/tonsil disorder did not change the association between obesity and otitis media. CONCLUSION: There is a clear association between childhood obesity and otitis media that cannot be explained by confounding by socioeconomic factors or clinically associated disorders.

Population prevalence of obstructive sleep apnoea in a community of German third graders.

We aimed to estimate the population prevalence of obstructive sleep apnoea (OSA) in an urban community of German third graders (age range 7.3-12.4 yrs) and the diagnostic test accuracy of two OSA screening methods. Using a cross-sectional study design with a multi-stage sampling strategy, 27 out of 59 primary schools within the city limits of Hanover, Germany, were selected. 1,144 third graders were screened for symptoms and signs of OSA using questionnaires and nocturnal home pulse oximetry. 183 children underwent abbreviated nocturnal home polysomnography (OSA definition: apnoea/hypopnoea index ≥1) and 22 were diagnosed to suffer from OSA. In general, sensitivity for both screening methods was low (<0.6), while specificity was moderately high (mostly >0.7). Independent predictors for OSA were body mass index, history of allergy, a composite questionnaire score, and two oximetry-based criteria. Based on these variables and logistic regression, a prediction model (accuracy; 95% confidence interval: 0.86; 0.71-0.94) was constructed and applied to children who had not successfully undergone polysomnography. This resulted in nine additional OSA cases and an overall design-adjusted population prevalence (95% confidence interval) of 2.8% (1.5-4.1%). Clinical and oximetry findings may be helpful for screening and predicting OSA in primary school children.

Randomised crossover trial of four nasal respiratory support systems for apnoea of prematurity in very low birthweight infants.

BACKGROUND: Apnoea of prematurity (AOP) is a common problem in preterm infants which can be treated with various modes of nasal continuous positive airway pressure (NCPAP) or nasal intermittent positive pressure ventilation (NIPPV). It is not known which mode of NCPAP or NIPPV is most effective for AOP. OBJECTIVE: To assess the effect of four NCPAP/NIPPV systems on the rate of bradycardias and desaturation events in very low birthweight infants. METHODS: Sixteen infants (mean gestational age at time of study 31 weeks, 10 males) with AOP were enrolled in a randomised controlled trial with a crossover design. The infants were allocated to receive nasal pressure support using four different modes for 6 h each: NIPPV via a conventional ventilator, NIPPV and NCPAP via a variable flow device, and NCPAP delivered via a constant flow underwater bubble system. The primary outcome was the cumulative event rate of bradycardias (< or =80 beats per minute) and desaturation events (< or =80% arterial oxygen saturation), which was obtained from cardio-respiratory recordings. RESULTS: The median event rate was 6.7 per hour with the conventional ventilator in NIPPV mode, and 2.8 and 4.4 per hour with the variable flow device in NCPAP and NIPPV mode, respectively (p value<0.03 for both compared to NIPPV/conventional ventilator). There was no significant difference between the NIPPV/conventional ventilator and the underwater bubble system. CONCLUSION: A variable flow NCPAP device may be more effective in treating AOP in preterm infants than a conventional ventilator in NIPPV mode. It remains unclear whether synchronised NIPPV would be even more effective.

Randomised crossover trial of different postural interventions on bradycardia and intermittent hypoxia in preterm infants.

BACKGROUND: Apnoea of prematurity has been shown to respond to changes in posture. OBJECTIVE: To investigate the effect of three postural interventions on the rate of bradycardia and desaturation events. METHODS: 18 infants (< or =32 weeks' gestational age; 11 boys) with apnoea of prematurity underwent recordings of breathing movements, electrocardiogram and instantaneous heart rate, pulse oximeter saturation (SpO2), photoplethysmographic waveforms and digital video frame while in one of three different prone positions. The following interventions were applied in random order: horizontal position (HP), 15 degrees head-up tilt position (TP) and three-level position (3P) according to Kinaesthetics Infant Handling. The primary study variable was the combined event rate of desaturations (SpO2 <85%) and bradycardias (heart rate <80 bpm). One secondary study variable was the duration of body movements. RESULTS: The median (range) combined event rate was 26.7/h (0.3-72.7) in HP, 25.2/h (0.3-70.5) in TP and 21.2/h (0-66.3) in 3P (p>0.05). The median (range) duration of body movements was 10.8 s/h (0-48.2) in HP, 7.1 s/h (0-72.4) in TP and 7.0 s/h (0-47.7) in 3P (p>0.05). CONCLUSIONS: No significant advantage of a head-up tilt or a three-level position over a standard horizontal position could be confirmed.

[Prevalence of sleep disorders in school children between 11 and 15 years of age]. / Häufigkeit von Schlafstörungen bei Schulkindern zwischen 11 und 15 Jahren.

UNLABELLED: Little is known about sleep disorders in children and adolescents that might affect physical and emotional well-being. Depending on age and size of the cohort group, and differences in questionnaires, prevalence varies between 1-43% in international studies. We examined the prevalence of symptoms characteristic of sleep disorders in school aged children with a questionnaire which allows indication of symptoms by the children themselves. METHODS: An anonymous questionnaire, based on the German Dresden questionnaire, with 22 questions concerning the main symptoms of obstructive sleep apnea syndrome (OSAS), general symptoms of para- and insomnia as well as sociodemographic data, was developed. 332 pupils (age: 11-15 y, mean: 12.75 y; median: 12 y; 56% female, 44% male) in 2 high schools in Vienna were investigated. RESULTS: 28% (n = 93/332) of the examined group reported snoring (the main symptom of OSAS) and/or insomnia (night waking almost every night) or parasomnia (nightmares, night terrors or sleepwalking almost every night). 15% (n = 14/93) of this subgroup reported snoring and para- or insomnia coincidentally. Girls were affected more frequently than boys by nocturnal awakening (79% vs. 56%, p < 0.001) and nightmares (64% vs. 52%, p < 0.01). The snoring group (21% (71/332) of all examined children) was affected more frequently by mouth dryness (16% vs. 4%, p < 0.001), pallor (7% vs. 3%, p < 0.01), night sweats (6% vs. 1%, p < 0.05) and from the following sleep disorders: nightmares (10% vs. 2%, p < 0.01), night terrors (4% vs. 1.5%, p < 0.001), sleepwalking (1.4% vs. 1%, p < 0.05) and nocturnal awakening (16% vs. 5%, p < 0.01). DISCUSSION: Almost every fifth child reports about at least one main symptom characteristic of OSAS. The statistically significant relation between symptoms of OSAS and non-organic sleep disorders shows the necessity of interdisciplinary focusing on sleep disorders. Further epidemiological studies need to be carried out in order to clarify the role of sleep anamnesis in the diagnosis and management of sleep disorders during childhood.

[Evaluation of the cardiorespiratory monitor SpiroGuard C for infants. Improved registration of respiratory events by new sensors and intelligent alarm management system]. / Evaluierung des Herz-Atem-Uberwachungsgerätes SpiroGuard C für Säuglinge. Verbesserte Erfassung von respiratorischen Ereignissen durch neue Sensorik und intelligentes Alarmmanagement?

OBJECTIVES: The SpiroGuard C is a commercially available cardiorespiratory monitor working with field plethysmography, wireless signal transmission and a novel alarm management system. In order to determine the recognition rates for central, mixed and obstructive apneas, a prospective clinical trial was performed comparing frequency and kind of signals from the monitor with those simultaneously registered by polysomnographic studies. DESIGN: Normal respiratory and alarm signals of the monitor under investigation were integrated into a polysomnographic setting. All central, mixed and obstructive apneas lasting more than 10 seconds as well as all alarms obtained from the monitor were evaluated. RESULTS: 47 series of monitor recordings could be evaluated in parallel to polysomnographic studies: the detection rate for central apneas was 298/328 (90.85%), for mixed apneas 9/41 (21.95%) and for obstructive apneas 0/36 (0%). Out of the total of 708 registered alarms 359 (50.71%) were false alarms, 307 (43.36%) were apnea-related and 42/708 (5.93%) were alarms due to technical problems. 177 of the 359 false alarms (49.30%) occurred during apneas that were shorter than 10 seconds, 119 (33.15%) were related to bad signal quality, and 55 (15.32%) were caused by movement artifacts. CONCLUSION: The recognition rate for central apneas was high (> 90%), while sensitivity for mixed and obstructive apneas was not satisfactory. Approximately half of the alarms were false alarms. These could be reduced by setting the apnea detection time to > 15 seconds, by tighter fastening of the respiration belt (improving the signal transmission), and by turning off the instrument when the child is awake and physically active. The wireless system renders the SpiroGuard C an attractive alternative for home monitoring.