Energy types of snoring sounds in patients with obstructive sleep apnea syndrome: a preliminary observation

Evolution of adherence and self-reported symptoms over 36 months with mandibular advancement device therapy for obstructive sleep apnea: a retrospective study

STUDY OBJECTIVES

Mandibular advancement devices (MAD) constitute a feasible option for management of mild-to-moderate obstructive sleep apnea (OSA) and in severe cases, when indicated. As a chronic condition, the management of OSA with MAD requires long-term patient adherence to treatment. The aim of the study was to investigate adherence to MAD therapy during a 36-month observation period in relation to changes in self-reported symptoms and objective response to therapy.

METHODS

Retrospective chart review of patients referred to the Orofacial Pain Clinic (University of Kentucky) between 2016 and 2021 for management of OSA with MAD was performed. Based on a posttreatment sleep study with MAD in situ, participants were subdivided into optimal response (> 50% reduction of baseline apnea-hypopnea index) and suboptimal response (< 50% reduction of baseline apnea-hypopnea index) groups. Outcomes included self-reported adherence to MAD use, self-reported OSA symptoms including snoring, apneic episodes, tiredness upon awakening, fatigue, and sleep quality (on a 100-mm numerical rating scale), and daytime sleepiness (0-24 on the Epworth Sleepiness Scale). Intragroup and intergroup differences at different time points over a 36-month observation period were assessed with one-way and repeated-measures analysis of variance.

RESULTS

Of 54 participants included (46.3% female, age 64.4 ± 10.71 years), 30 (55.6%) achieved optimal response and 24 (44.4%) achieved suboptimal response. At baseline, participants with optimal response differed from those with suboptimal response in apnea-hypopnea index (P = .007), snoring (P = .026), and sleep quality (P = .042). Although fluctuating in both groups, no difference was found over time in adherence (7 nights/wk, 7 h/night) and in OSA symptoms (all P > .05).

CONCLUSIONS

Adherence to MAD was maintained over 36 months regardless of fluctuation in self-reported OSA symptoms and effectiveness of MAD therapy.

CITATION

Sangalli L, Yanez-Regonesi F, Moreno-Hay I. Evolution of adherence and self-reported symptoms over 36 months with mandibular advancement device therapy for obstructive sleep apnea: a retrospective study. J Clin Sleep Med. 2024;20(4):487-496.

Obstructive sleep apnea diagnosis and beyond using portable monitors

Obstructive sleep apnea (OSA) is a chronic sleep and breathing disorder with significant health complications, including cardiovascular disease and neurocognitive impairments. To ensure timely treatment, there is a need for a portable, accurate and rapid method of diagnosing OSA. This review examines the use of various physiological signals used in the detection of respiratory events and evaluates their effectiveness in portable monitors (PM) relative to gold standard polysomnography. The primary objective is to explore the relationship between these physiological parameters and OSA, their application in calculating the apnea hypopnea index (AHI), the standard metric for OSA diagnosis, and the derivation of non-AHI metrics that offer additional diagnostic value. It is found that increasing the number of parameters in PMs does not necessarily improve OSA detection. Several factors can cause performance variations among different PMs, even if they extract similar signals. The review also highlights the potential of PMs to be used beyond OSA diagnosis. These devices possess parameters that can be utilized to obtain endotypic and other non-AHI metrics, enabling improved characterization of the disorder and personalized treatment strategies. Advancements in PM technology, coupled with thorough evaluation and validation of these devices, have the potential to revolutionize OSA diagnosis, personalized treatment, and ultimately improve health outcomes for patients with OSA. By identifying the key factors influencing performance and exploring the application of PMs beyond OSA diagnosis, this review aims to contribute to the ongoing development and utilization of portable, efficient, and effective diagnostic tools for OSA.

Palatal hybrid surgery for obstructive sleep apnea-state-of-the-art annotation of uvulopalatopharyngoplasty

BACKGROUND

Surgery for obstructive sleep apnea (OSA) has changed in concept and technique that transformed from radical excision to functional reconstruction. The aim of this study was to investigate the safety and effectiveness of palatal hybrid surgery in OSA patients.

METHODS

Palatal hybrid surgery is a tissue-specific technique (mucosa-preservation, tonsil-excision, fat-ablation, muscle-relocation/suspension) used in treating OSA patients with velopharyngeal obstruction. The study included 46 consecutive adults OSA patients. The palatal hybrid surgery annotates uvulopalatopharyngoplasty in stereoscopic reconstruction of tonsillar fossa (pharyngoplasty), omni-suspension of the soft palate (palatoplasty) and advancement of uvula (uvuloplasty).

RESULTS

No patient experienced airway compromise, voice change or persistent nasal regurgitation following palatal hybrid surgery. One patient existed postoperative tonsillar fossa bleeding received conservative treatment. Postoperative pain in visual analogue scale (VAS) showed average score of 3, 3, 2, 0 at the 1st, 3rd, 7th, 14th day, respectively. Perioperative snoring severity (VAS) (8.7 vs 2.6) and daytime sleepiness (Epworth Sleepiness Scale) (11.3 vs 5.5) all improved significantly (p < 0.001). Posterior air space in retropalatal area increased from 8.4 to 11.1 mm (p < 0.001). Home sleep test showed that apnea-hypopnea index significantly reduced from 41.8 to 18.2 event/h and minimal oxygen saturation increased from 72.4 to 81.5% (p < 0.001). The success rate in individual Friedman stage was 100% (stage I), 63% (stage II) and 58% (stage III) with a total success rate of 63%.

CONCLUSION

Palatal hybrid surgery using tissue-specific maneuver annotates UPPP in concept and technique. The results show that palatal hybrid surgery is mini-invasive with low morbid and is effective in improving subjective clinic symptoms, objective sleep parameters and success rate of OSA.

Obstructive Sleep Apnea and Auditory Dysfunction—Does Snoring Sound Play a Role?

The objective of the study was to investigate the relationship between obstructive sleep apnea (OSA) and auditory dysfunction, and to clarify the role of snoring sounds in contributing to auditory dysfunction. A comprehensive assessment of OSA and the auditory system was performed, including overnight polysomnography, detection of the intra-ear canal snoring sound energy (SSE), pure tone average (PTA), tinnitus pitch matching, the tinnitus handicap inventory (THI), and the Epworth sleepiness scale (ESS). The patients were identified as having tinnitus if their THI score was higher than zero or their tinnitus pitches were matched to specific frequencies. The median age, body mass index, and apnea–hypopnea index score were 41 years, 26.4 kg/m², and 29.9 events/h, respectively. Among the 50 participants, 46 (92%) had a normal PTA, and only 4 (8%) patients had mild hearing loss. There was no significant difference in PTA among OSA severities (p = 0.52). Among the 50 participants, 33 patients (66%) were identified as having tinnitus. In the tinnitus group (n = 33), the ESS score (p = 0.01) and intra-ear canal SSE of 851–1500 Hz (p = 0.04) were significantly higher than those in the non-tinnitus group (n = 17). OSA patients with a higher ESS score had a higher risk of tinnitus (odds ratio 1.22 [95% CI: 1.01–1.46]). OSA-related auditory dysfunction emerged in tinnitus rather than in hearing impairment. OSA patients with daytime sleepiness had a higher risk of tinnitus. High-frequency SSE can jeopardize cochlea and is a potential mechanism contributing to tinnitus. Detection of snoring sounds through an intra-ear canal device may be more precise in assessing acoustic trauma from snoring sounds to vulnerable auditory system and thus warrants further research.

Sound frequency spectra of snore in relation to the site of obstruction among snorers

Objective

This study aimed to describe the sound frequency of snoring in relation to the site of upper airway vibration among snorers.

Methods

383 snores from 40 participants who complained of snoring were digitally recorded during natural and induced sleep using a level III polysomnography monitor with a built-in microphone. During drug-induced sleep endoscopy (DISE), the real-time site of upper airway obstruction was assessed, and the sound frequency of snoring was recorded synchronously.

Results

The mean peak of snoring frequency for unilevel palatal, oropharynx and epiglottis obstruction were 522.5, 482.4 and 300.0 Hz, respectively. Most participants showed multilevel obstruction at the palate and oropharynx, in which the mean for bi-peak snoring frequency were 402.90 Hz and 1086.96 Hz, respectively. Severity of OSA was significantly associated with multilevel obstruction.

Conclusions

There was a significant association between the snoring sound frequency and site of unilevel obstruction. Palatal or oropharyngeal obstruction produced sound at mid-frequency range, while the epiglottis produced a low frequency range. Multilevel obstruction documented a bi-peak snoring frequency.

Comparative Effect of Fertilization Practices on Soil Microbial Diversity and Activity: An Overview

Continuously increasing human population demands increased food production, which needs greater fertilizer's input in agricultural lands to enhance crop yield. In this respect, different fertilization practices gained acceptance among farmers. We reviewed effect of three main fertilization practices (Conventional-, Organic-, and Bio-fertilization) on soil microbial diversity, activity, and community composition. Studies reported that over application of inorganic fertilizers decline soil pH, change soil osmolarity, cause soil degradation, disturb taxonomic diversity and metabolism of soil microbes and cause accumulation of extra nutrients into the soil such as phosphorous (P) accumulation. On the contrary, organic fertilizers increase organic carbon (OC) input in the soil, which strongly encourage growth of heterotrophic microbes. Organic fertilizer vermicompost application provides readily available nutrients to both plants as well as microbes and encourage overall microbial number in the soil. Most recently, role of beneficial bacteria in long-term sustainable agriculture attracted attention of scientists towards their use as biofertilizer in the soil. Studies documented favorable effect of biofertilization on microbial Shannon, Chao and ACE diversity indices in the soil. It is concluded from intensive review of literature that all the three fertilization practices have their own way to benefit the soil with nutrients, but biofertilization provides long-term sustainability to crop lands. When it is used in integration with organic fertilizers, it makes the soil best for microbial growth and activity and increase microbial diversity, providing nutrients to soil for a longer time, thus improving crop productivity.

Screening Severe Obstructive Sleep Apnea in Children with Snoring

Efficient screening for severe obstructive sleep apnea (OSA) is important for children with snoring before time-consuming standard polysomnography. This retrospective cross-sectional study aimed to compare clinical variables, home snoring sound analysis, and home sleep pulse oximetry on their predictive performance in screening severe OSA among children who habitually snored. Study 1 included 9 (23%) girls and 30 (77%) boys (median age of 9 years). Using univariate logistic regression models, 3% oxygen desaturation index (ODI3) ≥ 6.0 events/h, adenoidal-nasopharyngeal ratio (ANR) ≥ 0.78, tonsil size = 4, and snoring sound energy of 801–1000 Hz ≥ 22.0 dB significantly predicted severe OSA in descending order of odds ratio. Multivariate analysis showed that ODI3 ≥ 6.0 events/h independently predicted severe pediatric OSA. Among several predictive models, the combination of ODI3, tonsil size, and ANR more optimally screened for severe OSA with a sensitivity of 91% and a specificity of 94%. In Study 2 (27 (27%) girls and 73 (73%) boys; median age, 7 years), this model was externally validated to predict severe OSA with an accuracy of 76%. Our results suggested that home sleep pulse oximetry, combined with ANR, can screen for severe OSA more optimally than ANR and tonsil size among children with snoring.

An OSAHS evaluation method based on multi-features acoustic analysis of snoring sounds

Snoring is the most direct symptom of obstructive sleep apnea hypopnea syndrome (OSAHS) and implies a lot of information about OSAHS symptoms. This paper aimed to identify OSAHS patients by analyzing acoustic features derived from overnight snoring sounds. Mel-frequency cepstral coefficients, 800 Hz power ratio, spectral entropy and other 10 acoustic features were extracted from snores, and Top-6 features were selected from the extracted 10 acoustic features by a feature selection algorithm based on random forest, then 5 kinds of machine learning models were applied to validate the effectiveness of Top-6 features on identifying OSAHS patients. The results showed that when the classification performance and computing efficiency were taken into account, the combination of logistic regression model and Top-6 features performed best and could successfully distinguish OSAHS patients from simple snorers. The proposed method provides a higher accuracy for evaluating OSAHS with lower computational complexity. The method has great potential prospect for the development of a portable sleep snore monitoring device.

Activation of Neuropeptide Y2 Receptor Can Inhibit Global Cerebral Ischemia-Induced Brain Injury

Cardiopulmonary arrest (CA) can greatly impact a patient's life, causing long-term disability and death. Although multi-faceted treatment strategies against CA have improved survival rates, the prognosis of CA remains poor. We previously reported asphyxial cardiac arrest (ACA) can cause excessive activation of the sympathetic nervous system (SNS) in the brain, which contributes to cerebral blood flow (CBF) derangements such as hypoperfusion and, consequently, neurological deficits. Here, we report excessive activation of the SNS can cause enhanced neuropeptide Y levels. In fact, mRNA and protein levels of neuropeptide Y (NPY, a 36-amino acid neuropeptide) in the hippocampus were elevated after ACA-induced SNS activation, resulting in a reduced blood supply to the brain. Post-treatment with peptide YY_3-36 (PYY_3-36), a pre-synaptic NPY2 receptor agonist, after ACA inhibited NPY release and restored brain circulation. Moreover, PYY_3-36 decreased neuroinflammatory cytokines, alleviated mitochondrial dysfunction, and improved neuronal survival and neurological outcomes. Overall, NPY is detrimental during/after ACA, but attenuation of NPY release via PYY_3-36 affords neuroprotection. The consequences of PYY_3-36 inhibit ACA-induced 1) hypoperfusion, 2) neuroinflammation, 3) mitochondrial dysfunction, 4) neuronal cell death, and 5) neurological deficits. The present study provides novel insights to further our understanding of NPY's role in ischemic brain injury.

Shifting and reducing breathing disturbance in patients with very severe obstructive sleep apnea by modified Z-palatoplasty with one-layer closure in one-stage multilevel surgery

Very severe obstructive sleep apnea (OSA) with apnea-hypopnea index (AHI) ≥ 60 events/h differs in several areas from OSA with other severities, including having a low-level daytime partial pressure of oxygen and residual on-CPAP (continuous positive airway pressure) AHIs greater than 20/h. Patients with very severe OSA show narrow retroglossal space and confined framework, which is difficult to be enlarged via conventional Uvulopalatopharyngoplasty (UPPP) surgery, resulting in poor response to non-framework surgeries. Our latest report showed efficacy and efficiency for subjects undergoing modified Z-palatoplasty (ZPP) with one-layer closure in a one-stage multilevel surgery. It is unclear whether and how this procedure could help patients with very severe OSA characterized with confined framework. From Mar. 2015 to May 2018, we enrolled 12 patients with very severe OSA receiving one-stage multi-level surgery with modified ZPP with one-layer closure, CO2 laser partial tongue-base glossectomy, and bilateral septomeatoplasty. Our results show that the surgery reduced AHI from 73.8 ± 10.7 to 30.8 ± 23.2 events/h and achieved a mean AHI reduction of 58.3% (p < 0.001 against 0 reduction or no surgery). The surgery shifted components of the breathing disturbances. It reduced more apnea than hypopnea and might convert some apnea to hypopnea.

Snoring Sound Characteristics are Associated with Common Carotid Artery Profiles in Patients with Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) and snoring have been reported to be modifiable risk factors for thick carotid intima-media thickness (CIMT) and carotid atherosclerosis, which are closely linked to cardiovascular disease.

METHODS

This cross-sectional study prospectively recruited 70 participants with OSA and without a history of carotid artery disorder, who primarily sought surgical Intervention. OSA and snoring were assessed with the Epworth Sleepiness Scale, Snore Outcomes Survey, polysomnography, and snoring sound recording. The carotid arteries were evaluated with ultrasonography and divided into three types of carotid artery profiles (normal carotid artery, thick CIMT, or significant carotid atherosclerosis). Multivariate linear/logistic/categorical regressions were performed with the forward selection approaches/logistic least absolute shrinkage and selection operator, as appropriate.

RESULTS

Normalized snoring sound energy (301-850 Hz) was independently associated with the carotid intima-media thickness (regression coefficient [β] = 0.01, standard error [SE] = 0.004, P = 0.03; R ² = 0.067) and type of carotid profile (β = 0.40, SE = 0.09, P < 0.001; R ² = 0.156). Normalized snoring sound energy (4-300 Hz) (β = -0.10, SE = 0.04, P = 0.01) and female sex (β = 1.90, SE = 0.94, P = 0.04) were independently related to the presence of carotid stenosis (R ² = 0.159). The optimal regression model of the type of carotid artery profile included normalized snoring sound energy (301-850 Hz) (β = 0.33, SE = 0.14, P = 0.03), snoring time (β = 0.26, SE = 0.13, P = 0.047), female sex (β = 0.26, SE = 0.13, P = 0.047), and increased age (β = 0.20, SE = 0.10, P = 0.04) under the control of the Snore Outcomes Survey score, 3% oxygen desaturation index, snoring sound energy (4-1500 Hz), normalized snoring sound energy (851-1500 Hz), cigarette smoking, and hyperlipidemia (R ² = 0.427).

CONCLUSION

Our findings suggested that snoring sound characteristics are associated with carotid artery profiles among early OSA patients who cannot be noticed by ultrasound because organic changes of the carotid artery have not yet started. Future studies are warranted to verify the clinical significance of the results.

Balance disorders as potential confounders associated with an increased risk of acute cerebrovascular accidents

PURPOSE

There is a higher risk of stroke after suffering from balance disorders (BDs) such as vertigo or dizziness. The causal relationship remains unclear due to the limited scope of the existing studies and the high prevalence of cardiovascular risk factors (CVRFs) in BD patients. The objective of this study is to clarify the role that BDs seem to have in the development of acute cerebrovascular accidents (ACAs).

METHODS

This is an observational prospective study. The CVRFs and demographic factors of a sample of our population were noted. Five clusters of patients were tracked over the course of 2 years to detect and diagnose BDs and ACAs. The causal relationships between the CVRFs, BDs and ACAs were analyzed in a univariate analysis. A logistic regression multivariant analysis was performed on those variables that reached statistical significance.

RESULTS

The sample included 7886 participants and 31 ACAs were recorded. CVRFs that reached statistical significance included age ≥ 60, hypertension, diabetes mellitus, dyslipidemia, ischemic heart disease, atrial fibrillation and previous ACAs. The relationship between BDs and ACAs always reached statistical significance, regardless of how the BD variable was defined. Five different multivariate analyses were performed, but in none of them did the BD variables significantly reduce the deviance and thus, they were not taken into account when building the final model.

CONCLUSION

This study shows that BDs are probably confounders that are closely linked to other CVRFs and they are also useful red flags to identify patients at a higher risk of suffering from ACAs.

A Non-Framework Multilevel Surgery May Reduce Mean Heart Rate in Patients with Very Severe Obstructive Apnea Having Confined Retroglossal Space and Framework

An elevated mean heart rate in untreated patients of obstructive sleep apnea (OSA) may lead to a higher risk of mortality and the development of various cardiovascular diseases. The elevation may positively relate to the severity of OSA and present in both wakefulness and sleep. A reduction in heart rate has been presented in reports of treating OSA patients with continuous positive airway pressure (CPAP). However, patients with very severe OSA may refuse use of CPAP devices and advocated surgeries, such as direct skeletal surgery or tracheostomy. It is unclear whether the non-framework multilevel surgery we reported previously can overcome the unfavorable anatomy and reduce mean heart rate, which serves as a risk factor of mortality. Here, we show that multilevel surgery reduced the mean heart rate from 68.6 to 62.7 with a mean reduction of 5.9 beats/min. The results suggest that the surgery may reduce the risk of consequences and mortality associated with an elevated mean heart rate, such as various cardiovascular diseases. We disclose these findings, along with the variations and possible risks to our future patients with very severe OSA who refuse or cannot use a CPAP device or reject direct skeletal surgery.

Increasing Hypopnea in Sleep Breathing Disturbance Improves Postoperative Oxygen Saturation in Patients with Very Severe Obstructive Sleep Apnea

In patients of very severe obstructive sleep apnea (OSA) with confined framework, reducing volume is difficult to achieve a postoperative apnea-hypopnea index (AHI) qualifying the classical surgical success. However, a higher AHI with a larger part of hypopneas may have similar or even less severity of oxygen (O2) desaturation, compared to a lower index mostly made of apneas. Here, in 27 consecutive enrolled patients, we show that besides the improvement of mean AHI, the multilevel surgery increased hypopnea in AHI from 29.1% to 77.3%, and improves postoperative O2 saturation by reducing desaturation frequency (mean desaturation index decreased from 62.5 to 24.4 events/h) and level (mean oxyhemoglobin saturation of pulse oximetry (SpO2) desaturation cut down from 10.0 to 5.8%). The mean SpO2 improved from 92.3% to 94.7%, and the improvement was positively related to the proportion increase of hypopnea/AHI. The results suggest that the non-framework surgery could help patients with very severe OSA whose AHIs are ≥60 events/h in terms of improving postoperative O2 saturation. Due to the improvement also presented in those not qualified as classical surgical success, further studies are needed to clarify the connection between O2 desaturation and various consequences to reconsider defining a surgical success.

Pan-genome analysis of Paenibacillus polymyxa strains reveals the mechanism of plant growth promotion and biocontrol

Rapid development of gene sequencing technologies has led to an exponential increase in microbial sequencing data. Genome research of a single organism does not capture the changes in the characteristics of genetic information within a species. Pan-genome analysis gives us a broader perspective to study the complete genetic information of a species. Paenibacillus polymyxa is a Gram-positive bacterium and an important plant growth-promoting rhizobacterium with the ability to produce multiple antibiotics, such as fusaricidin, lantibiotic, paenilan, and polymyxin. Our study explores the pan-genome of 14 representative P. polymyxa strains isolated from around the world. Heap's law model and curve fitting confirmed an open pan-genome of P. polymyxa. The phylogenetic and collinearity analyses reflected that the evolutionary classification of P. polymyxa strains are not associated with geographical area and ecological niches. Few genes related to phytohormone synthesis and phosphate solubilization were conserved; however, the nif cluster gene associated with nitrogen fixation exists only in some strains. This finding is indicative of nitrogen fixing ability is not stable in P. polymyxa. Analysis of antibiotic gene clusters in P. polymyxa revealed the presence of these genes in both core and accessory genomes. This observation indicates that the difference in living environment led to loss of ability to synthesize antibiotics in some strains. The current pan-genomic analysis of P. polymyxa will help us understand the mechanisms of biological control and plant growth promotion. It will also promote the use of P. polymyxa in agriculture.

Circulating miRNAs as molecular markers of occupational grain dust exposure

Dust from grain and feed production may cause adverse health effects in exposed workers. In this study we explored circulating miRNAs as potential biomarkers of occupational grain dust exposure. Twenty-two serum miRNAs were analyzed in 44 grain dust exposed workers and 22 controls. Exposed workers had significantly upregulated miR-18a-5p, miR-124-3p and miR-574-3p, and downregulated miR-19b-3p and miR-146a-5p, compared to controls. Putative target genes for the differentially expressed miRNAs were involved in a range of Kyoto Encyclopedia of Genes and Genomes signaling pathways, and ‘Pathways in cancer’ and ‘Wnt signaling pathway’ were common for all the five miRNAs. MiRNA-diseases association analysis showed a link between the five identified miRNAs and several lung diseases terms. A positive correlation between miR-124-3p, miR-18a-5p, and miR-574-3p and IL-6 protein level was shown, while miR-19b-3p was inversely correlated with CC-16 and sCD40L protein levels. Receiver-operating characteristic analysis of the five miRNA showed that three miRNAs (miR-574-3p, miR-124-3p and miR-18a-5p) could distinguish the grain dust exposed group from the control group, with miR-574-3p as the strongest predictor of grain dust exposure. In conclusion, this study identified five signature miRNAs as potential novel biomarkers of grain dust exposure that may have potential as early disease markers.

A New Feature with the Potential to Detect the Severity of Obstructive Sleep Apnoea via Snoring Sound Analysis

The severity of obstructive sleep apnoea (OSA) is diagnosed with polysomnography (PSG), during which patients are monitored by over 20 physiological sensors overnight. These sensors often bother patients and may affect patients’ sleep and OSA. This study aimed to investigate a method for analyzing patient snore sounds to detect the severity of OSA. Using a microphone placed at the patient’s bedside, the snoring and breathing sounds of 22 participants were recorded while they simultaneously underwent PSG. We examined some features from the snoring and breathing sounds and examined the correlation between these features and the snore-specific apnoea-hypopnea index (ssAHI), defined as the number of apnoea and hypopnea events during the hour before a snore episode. Statistical analyses revealed that the ssAHI was positively correlated with the Mel frequency cepstral coefficients (MFCC) and volume information (VI). Based on clustering results, mild snore sound episodes and snore sound episodes from mild OSA patients were mainly classified into cluster 1. The results of clustering severe snore sound episodes and snore sound episodes from severe OSA patients were mainly classified into cluster 2. The features of snoring sounds that we identified have the potential to detect the severity of OSA.

Why and When to Treat Snoring

It is estimated that half of the adult population older than 60 years snores. This article discusses the many aspects of snoring, including impacts on bed partners, the individual who snores, and when and how to appropriately evaluate, diagnose, and treat the perpetrator. The goal is for clinicians to expand their knowledge regarding diagnosis and treatment of the phenomenon of snoring.It is estimated that half of the adult population over the age of 60 years of age snores. This chapter discusses snoring, including the impact on bed partners, the individual that snores and when and how to treat the snorer. The goal is for clinicians to expand their knowledge regarding diagnosis and treatment of patients who snores.

Blood mRNA expression of REV3L and TYMS as potential predictive biomarkers from platinum-based chemotherapy plus pemetrexed in non-small cell lung cancer patients

PURPOSE

Therapeutic options for cancer patients have increased in the last years, although drugs resistance problem remains unresolved. Genetic background in individual susceptibility to cancer treatment could influence the therapy responses. The aim of this study was to explore the feasibility of using blood 4 genes (AEG-1, BRCA-1, REV3L and TYMS) expression levels as a predictor of the efficacy of pemetrexed therapy in patients with advanced non-small cell lung cancer.

METHODS

Sixteen patients from the Medical Oncology Department at "12 de Octubre" Hospital, were included in the study. Total mRNA was isolated from blood samples, and gene expression was analyzed by RT-qPCR. A panel of lung tumor cell lines were used in cell proliferation tests and siRNA-mediated silencing assays.

RESULTS

Similarity between blood gene expression levels and protein expression in matched tumor tissue was observed in 54.54% (REV3L) and 81.81% (TYMS) of cases. Gene expression of REV3L and TYMS in blood correlated directly and inversely, respectively, with progression-free survival and overall survival in the patients from our cohort. In tumor cell lines, the knockdown of REV3L conferred resistance to pemetrexed treatment, and the TYMS silencing increased the pemetrexed sensitivity of tumor cells.

CONCLUSIONS

The use of peripheral blood samples for expression quantification of interest genes is an affordable method with promising results in the evaluation of response to pemetrexed treatment. Therefore, expression levels of REV3L and TYMS genes might be used as predictive biomarkers in advanced NSCLC patients.

Recurrent Neural Network for Classification of Snoring and Non-Snoring Sound Events

Obstructive sleep apnea (OSA) is a disorder that affects up to 38% of the western population. It is characterized by repetitive episodes of partial or complete collapse of the upper airway during sleep. These episodes are almost always accompanied by loud snoring. Questionnaires such as STOP-BANG exploit snoring to screen for OSA. However, they are not quantitative and thus do not exploit its full potential. A method for automatic detection of snoring in whole-night recordings is required to enable its quantitative evaluation. In this study, we propose such a method. The centerpiece of the proposed method is a recurrent neural network for modeling of sequential data with variable length. Mel-frequency cepstral coefficients, which were extracted from snoring and non-snoring sound events, were used as inputs to the proposed network. A total of 20 subjects referred to clinical sleep recording were also recorded by a microphone that was placed 70 cm from the top end of the bed. These recordings were used to assess the performance of the proposed method. When it comes to the detection of snoring events, our results show that the proposed method has an accuracy of 95%, sensitivity of 92%, and specificity of 98%. In conclusion, our results suggest that the proposed method may improve the process of snoring detection and with that the process of OSA screening. Follow-up clinical studies are required to confirm this potential.

Associations of snoring frequency and intensity in pregnancy with time-to-delivery

BACKGROUND

Sleep-disordered breathing (SDB) is linked to adverse pregnancy outcomes. However, little is known about the association of SDB with timing of delivery. We examined the association of snoring frequency, a key SDB marker, and snoring intensity, a correlate of SDB severity, with time-to-delivery among a cohort of pregnant women.

METHODS

In this prospective cohort study, 1483 third trimester pregnant women were recruited from the University of Michigan prenatal clinics. Women completed a questionnaire about their sleep, and demographic and pregnancy information was abstracted from medical charts. After exclusion of those with hypertension or diabetes, 954 women were classified into two groups by their snoring onset timing, chronic or pregnancy-onset. Within each of these groups, women were divided into four groups based on their snoring frequency and intensity: non-snorers; infrequent-quiet; frequent-quiet; or frequent-loud snorers. Cox proportional hazard regression models were used to investigate the association between snoring frequency and intensity and time-to-delivery, adjusting for maternal characteristics.

RESULTS

Chronic snoring was reported by half of the pregnant women, and of those, 7% were frequent-loud snorers. Deliveries before 38 weeks' gestation are completed occurred among 25% of women with chronic, frequent-loud snoring. Compared with pre-pregnancy non-snorers, women with chronic frequent-loud snoring had an increased hazard ratio for delivery (adjusted hazard ratio 1.60, 95% confidence interval 1.04, 2.45).

CONCLUSIONS

Snoring frequency and intensity is associated with time-to-delivery in women absent of hypertension or diabetes. Frequent-loud snoring may have a clinical utility to identify otherwise low-risk women who are likely to deliver earlier.

Snoring sound energy as a potential biomarker for disease severity and surgical response in childhood obstructive sleep apnoea: A pilot study

OBJECTIVE

To investigate the relationship between baseline snoring sound energy (SSE) and disease severity, changes in SSE after adenotonsillectomy, and the predictors of surgical success in children with obstructive sleep apnoea (OSA).

DESIGN

Prospective cohort study.

SETTING

Tertiary referral medical centre.

PARTICIPANTS

Thirty-two children with OSA whose apnoea-hypopnoea index ≥5 or apnoea-hypopnoea index ≥1.5 with OSA comorbidities were recruited. Patients with complicated OSA were excluded. All participants underwent snoring sound analysis, polysomnography, and adenotonsillectomy.

MAIN OUTCOME MEASURES

Snoring sound energy and apnoea-hypopnoea index were assessed at baseline and 6 months after adenotonsillectomy. Surgical success was defined as a postoperative apnoea-hypopnoea index <1.5.

RESULTS

The median age, body mass index, and apnoea-hypopnoea index was 9 years, 19.0 kg/m² , and 13.2 events/h, respectively. Multivariate logistic regression showed that a baseline tonsil size of IV (odds ratio 15.7 [95% CI: 1.5-166.3]) and SSE of 801-1000 Hz > 21.9 dB (odds ratio 32.3 [95% CI: 2.6-396.6]) were significantly related to severe OSA. Following adenotonsillectomy, apnoea-hypopnoea index decreased significantly (P < 0.001). SSE of 41-200 Hz, 201-400 Hz and 801-1000 Hz also decreased significantly (P = 0.04, 0.01 and 0.006, respectively). Baseline SSE of 801-1000 Hz < 8.5 dB significantly predicted surgical success (odds ratio 11.0 [95% CI: 1.4-85.2]).

CONCLUSIONS

Our findings suggest the potential utility of SSE of 801-1000 Hz to screen for severe OSA, predict surgical success and assess therapeutic outcomes. Specific baseline SSE may represent a potential biomarker for childhood OSA.

Sleep Apnea Detection Based on Thoracic and Abdominal Movement Signals of Wearable Piezo-Electric Bands

Physiologically, the thoracic (THO) and abdominal (ABD) movement signals, captured using wearable piezo-electric bands, provide information about various types of apnea, including central sleep apnea (CSA) and obstructive sleep apnea (OSA). However, the use of piezo-electric wearables in detecting sleep apnea events has been seldom explored in the literature. This study explored the possibility of identifying sleep apnea events, including OSA and CSA, by solely analyzing one or both the THO and ABD signals. An adaptive non-harmonic model was introduced to model the THO and ABD signals, which allows us to design features for sleep apnea events. To confirm the suitability of the extracted features, a support vector machine was applied to classify three categories - normal and hypopnea, OSA, and CSA. According to a database of 34 subjects, the overall classification accuracies were on average 75.9%±11.7% and 73.8%±4.4%, respectively, based on the cross validation. When the features determined from the THO and ABD signals were combined, the overall classification accuracy became 81.8%±9.4%. These features were applied for designing a state machine for online apnea event detection. Two event-byevent accuracy indices, S and I, were proposed for evaluating the performance of the state machine. For the same database, the S index was 84.01%±9.06%, and the I index was 77.21%±19.01%. The results indicate the considerable potential of applying the proposed algorithm to clinical examinations for both screening and homecare purposes.

Automatic Video Analysis for Obstructive Sleep Apnea Diagnosis

STUDY OBJECTIVES

We investigated the diagnostic accuracy for the identification of obstructive sleep apnea (OSA) and its severity of a noninvasive technology based on image processing (SleepWise).

METHODS

This is an observational, prospective study to evaluate the degree of agreement between polysomnography (PSG) and SleepWise. We recruited 56 consecutive subjects with suspected OSA who were referred as outpatients to the Sleep Unit of the Hospital Universitari Germans Trias i Pujol (HUGTiP) from January 2013 to January 2014. All patients underwent laboratory PSG and image processing with SleepWise simultaneously the same night. Both PSG and SleepWise analyses were carried independently and blindly.

RESULTS

We analyzed 50 of the 56 patients recruited. OSA was diagnosed through PSG in a total of 44 patients (88%) with a median apnea-hypopnea index (AHI) of 25.35 (24.9). According to SleepWise, 45 patients (90%) met the criteria for a diagnosis of OSA, with a median AHI of 22.8 (22.03). An analysis of the ability of PSG and SleepWise to classify patients by severity on the basis of their AHI shows that the two diagnostic systems distribute the different groups similarly. According to PSG, 23 patients (46%) had a diagnosis of severe OSA, 11 patients (22%) moderate OSA, and 10 patients (20%) mild OSA. According to SleepWise, 20, 13, and 12 patients (40%, 26%, and 24%, respectively) had a diagnosis of severe, moderate, and mild OSA respectively. For OSA diagnosis, SleepWise was found to have sensitivity of 100% and specificity of 83% in relation to PSG. The positive predictive value was 97% and the negative predictive value was 100%. The Bland-Altman plot comparing the mean AHI values obtained through PSG and SleepWise shows very good agreement between the two diagnostic techniques, with a bias of -3.85, a standard error of 12.18, and a confidence interval of -0.39 to -7.31.

CONCLUSIONS

SleepWise was reasonably accurate for noninvasive and automatic diagnosis of OSA in outpatients. SleepWise determined the severity of OSA with high reliability. The current study including simultaneous laboratory PSG and SleepWise processing image is proposed as a reasonable validation standard.

The Frequency and Energy of Snoring Sounds Are Associated with Common Carotid Artery Intima-Media Thickness in Obstructive Sleep Apnea Patients

Obstructive sleep apnea (OSA) is a known risk factor for atherosclerosis. We investigated the association of common carotid artery intima-media thickness (CCA-IMT) with snoring sounds in OSA patients. A total of 30 newly diagnosed OSA patients with no history of cardiovascular diseases were prospectively enrolled for measuring mean CCA-IMT with B-mode ultrasonography, body mass index, metabolic syndrome, 10-year cardiovascular disease risk score, high-sensitivity C-reactive protein, and homocysteine. Good-quality signals of full-night snoring sounds in an ordinary sleep condition obtained from 15 participants were further acoustically analyzed (Included group). All variables of interest were not significantly different (all p > 0.05) between the included and non-included groups except for diastolic blood pressure (p = 0.037). In the included group, CCA-IMT was significantly correlated with snoring sound energies of 0–20 Hz (r = 0.608, p = 0.036) and 652–1500 Hz (r = 0.632, p = 0.027) and was not significantly associated with that of 20–652 Hz (r = 0.366, p = 0.242) after adjustment for age and sex. Our findings suggest that underlying snoring sounds may cause carotid wall thickening and support the large-scale evaluation of snoring sound characters as markers of surveillance and for risk stratification at diagnosis.

Snoring Sounds Predict Obstruction Sites and Surgical Response in Patients with Obstructive Sleep Apnea Hypopnea Syndrome

Snoring sounds generated by different vibrators of the upper airway may be useful indicators of obstruction sites in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). This study aimed to investigate associations between snoring sounds, obstruction sites, and surgical responses (≥50% reduction in the apnea-hypopnea index [AHI] and <10 events/hour) in patients with OSAHS. This prospective cohort study recruited 36 OSAHS patients for 6-hour snoring sound recordings during in-lab full-night polysomnography, drug-induced sleep endoscopy (DISE), and relocation pharyngoplasty. All patients received follow-up polysomnography after 6 months. Fifteen (42%) patients with at least two complete obstruction sites defined by DISE were significantly, positively associated with maximal snoring sound intensity (40-300 Hz; odds ratio [OR], 1.25, 95% confidence interval [CI] 1.05-1.49) and body mass index (OR, 1.48, 95% CI 1.02-2.15) after logistic regression analysis. Tonsil obstruction was significantly, inversely correlated with mean snoring sound intensity (301-850 Hz; OR, 0.84, 95% CI 0.74-0.96). Moreover, baseline tonsil obstruction detected by either DISE or mean snoring sound intensity (301-850 Hz), and AHI could significantly predict the surgical response. Our findings suggest that snoring sound detection may be helpful in determining obstruction sites and predict surgical responses.

Changes of snoring sound after relocation pharyngoplasty for obstructive sleep apnoea: the surgery reduces mean intensity in snoring which correlates well with apnoea-hypopnoea index

OBJECTIVE

To investigate objective changes of snoring after surgery in patients with obstructive sleep apnoea (OSA) and correlate these with changes in the apnoea-hypopnoea index (AHI).

DESIGN

Prospective case series.

SETTING

A novel measurement, Snore Map, was used to analyse full-night snore sounds in terms of the maximal/mean intensity, peak/mean frequency, snoring index and energy type (Snore Map type, 0-4). Snore sound was classified into three bands according to frequency energy spectrum: B1 (40-300 Hz), B2 (301-850 Hz) and B3 (851-2000 Hz).

PARTICIPANTS

Thirty-four male and two female OSA patients (mean age, 39 years; mean AHI, 53.1/h; mean body mass index, 26.8 kg/m(2) ) with favourable anatomic structure were consecutively enrolled.

MAIN OUTCOME MEASURES

Parameters of polysomnographies and Snore Maps at baseline and six months after operation were compared. Statistical significance was set at P < 0.05.

RESULTS

Thirty-two patients completed this study. The mean reduction in the total-snoring index was insignificant but there were significant decreases in total mean intensity, total peak frequency, total mean frequency and Snore Map type after surgery. There were also significant decreases in the mean intensity in all three bands, the snoring index in B2/B3 and the mean frequency in B1 postoperatively. Changes in the total mean intensity, total mean frequency, B2 mean intensity and B3 snoring index positively correlated with change in the AHI.

CONCLUSIONS

Relocation pharyngoplasty significantly decreases both the snoring sound intensity and snoring frequency. These reductions are directly proportional to the improvement of OSA.

Treatment of snoring with positional therapy in patients with positional obstructive sleep apnea syndrome

Position therapy plays a role in treating snoring and obstructive sleep apnea syndrome (OSAS). The purpose of this study was to investigate whether position therapy using a head-positioning pillow (HPP) could reduce snoring sounds in patients with mild-to-moderate positional OSAS, taking into account the potential confounding effects of body weight. A total of 25 adults with positional OSAS (apnea-hypopnea index [AHI]_supine:AHI_non-supine ≥ 2) were prospectively enrolled. Patients were asked to use their own pillows at home during the first night (N₀), and the HPP during the second (N₁) and third (N₂) nights. The primary outcome measures included the subjective snoring severity (SS, measured on a visual analogue scale ranging from 0 to 10) and the objective snoring index (SI, expressed as the number of snoring events per hour measured on an acoustic analytical program). Both endpoints were recorded over three consecutive nights. From N₀ to N₂, the median SS and SI values in the entire study cohort decreased significantly from 5.0 to 4.0 and from 218.0 events/h to 115.0 events/h, respectively. In the subgroup of overweight patients, SS showed a significant improvement, whereas SI did not. Both SS and SI were found to be significantly improved in normal-weight patients.

Acoustic Analysis of Snoring in the Diagnosis of Obstructive Sleep Apnea Syndrome: A Call for More Rigorous Studies

BACKGROUND

Snoring is a common symptom of obstructive sleep apnea syndrome (OSA) and has recently been considered for diagnosis of OSA.

OBJECTIVES

The goal of the current study was to systematically determine the accuracy of acoustic analysis of snoring in the diagnosis of OSA using a meta-analysis.

METHODS

PubMed, Cochrane Library database, and EMBASE were searched up to July 15, 2014. A systematic review and meta-analysis of sensitivity, specificity, and other measures of accuracy of acoustic analysis of snoring in the diagnosis of OSA were conducted. The median of apneahypopnea index threshold was 10 events/h, range: 5-15 or 10-15 if aforementioned suggestion is adopted.

RESULTS

A total of seven studies with 273 patients were included in the meta-analysis. The pooled estimates were as follows: sensitivity, 88% (95% confidence interval [CI]: 82-93%); specificity, 81% (95% CI: 72-88%); positive likelihood ratio (PLR), 4.44 (95% CI: 2.39-8.27); negative likelihood ratio (NLR), 0.15 (95% CI: 0.10-0.24); and diagnostic odds ratio (DOR), 32.18 (95% CI: 13.96-74.81). χ(2) values of sensitivity, specificity, PLR, NLR, and DOR were 2.37, 10.39, 12.57, 3.79, and 6.91 respectively (All p > 0.05). The area under the summary receiver operating characteristic curve was 0.93. Sensitivity analysis demonstrated that the pooled estimates were stable and reliable. The results of publication bias were not significant (p = 0.30).

CONCLUSIONS

Acoustic analysis of snoring is a relatively accurate but not a strong method for diagnosing OSA. There is an urgent need for rigorous studies involving large samples and single snore event tests with an efficacy criterion that reflects the particular features of snoring acoustics for OSA diagnosis.

Nocturnal snoring sound analysis in the diagnosis of obstructive sleep apnea in the Chinese Han population

PURPOSE

Loud snoring is one of the principle symptoms of obstructive sleep apnea (OSA). Snoring sound analysis is a potentially cost-effective, reliable alternative for the diagnosis of OSA. However, no investigation has determined the accuracy of snoring signal analysis for the diagnosis of OSA in the Chinese Han population. Therefore, we investigated whether whole-night snoring detection and analysis aids the diagnosis of OSA using a new snore analysis technique.

METHODS

Snoring sounds were recorded using a non-contact microphone and polysomnography (PSG) was performed simultaneously throughout the night. We randomly selected 30 subjects each from four groups based on the severity of OSA. The rhythm and frequency domain of the snoring signal were analyzed based on frequency energy endpoint detection (FEP) and the Earth mover's distance (EMD), for each subject to harvest the EMD-calculated Apnea-Hypopnea Index (AHIEMD). Finally, we compared the AHIEMD with the PSG-monitored AHI (AHIPSG).

RESULTS

The accuracy of the AHIEMD compared with the AHIPSG was 96.7, 86.7, 86.7, and 96.7% in non-, mild, moderate, and severe OSA patients, respectively. AHIEMD was correlated with AHIPSG (r(2) = 0.950, p < 0.001). The area under the receiver operating characteristic curve values for OSA detection was 0.974, 0.957, and 0.997 for AHIEMD thresholds of 5, 15, and 30 events/h, respectively. Bland-Altman analysis revealed 91.7% agreement of AHIEMD with AHIPSG.

CONCLUSIONS

This new method for identifying OSA by analyzing snoring is feasible and reliable in the Han population. The snoring sound-based technique appears to be a promising tool for OSA screening and diagnosis.

Comparative effects of snoring sound between two minimally invasive surgeries in the treatment of snoring: a randomized controlled trial

Background

Minimally invasive surgeries of the soft palate have emerged as a less-invasive treatment for habitual snoring. To date, there is only limited information available comparing the effects of snoring sound between different minimally invasive surgeries in the treatment of habitual snoring.

Objective

To compare the efficacy of palatal implant and radiofrequency surgery, in the reduction of snoring through subjective evaluation of snoring and objective snoring sound analysis.

Patients and Method

Thirty patients with habitual snoring due to palatal obstruction (apnea-hypopnea index ≤15, body max index ≤30) were prospectively enrolled and randomized to undergo a single session of palatal implant or temperature-controlled radiofrequency surgery of the soft palate under local anesthesia. Snoring was primarily evaluated by the patient with a 10 cm visual analogue scale (VAS) at baseline and at a 3-month follow-up visit and the change in VAS was the primary outcome. Moreover, life qualities, measured by snore outcomes survey, and full-night snoring sounds, analyzed by a sound analytic program (Snore Map), were also investigated at the same time.

Results

Twenty-eight patients completed the study; 14 received palatal implant surgery and 14 underwent radiofrequency surgery. The VAS and snore outcomes survey scores were significantly improved in both groups. However, the good response (postoperative VAS ≤3 or postoperative VAS ≤5 plus snore outcomes survey score ≥60) rate of the palatal implant group was significantly higher than that of the radiofrequency group (79% vs. 29%, P = 0.021). The maximal loudness of low-frequency (40–300 Hz) snores was reduced significantly in the palatal implant group. In addition, the snoring index was significantly reduced in the radiofrequency group.

Conclusions

Both palatal implants and a single-stage radiofrequency surgery improve subjective snoring outcomes, but palatal implants have a greater effect on most measures of subjective and objective snoring. Multi-stage radiofrequency surgery was not tested.

Trial Registration

ClinicalTrials.gov NCT01955083

Monitoring sound to quantify snoring and sleep apnea severity using a smartphone: proof of concept

STUDY OBJECTIVES

Habitual snoring is a prevalent condition that is not only a marker of obstructive sleep apnea (OSA) but can also lead to vascular risk. However, it is not easy to check snoring status at home. We attempted to develop a snoring sound monitor consisting of a smartphone alone, which is aimed to quantify snoring and OSA severity.

METHODS

The subjects included 50 patients who underwent diagnostic polysomnography (PSG), of which the data of 10 patients were used for developing the program and that of 40 patients were used for validating the program. A smartphone was attached to the anterior chest wall over the sternum. It acquired ambient sound from the built-in microphone and analyzed it using a fast Fourier transform on a real-time basis.

RESULTS

Snoring time measured by the smartphone highly correlated with snoring time measured by PSG (r = 0.93). The top 1 percentile value of sound pressure level (L1) determined by the smartphone correlated with the ambient sound L1 during sleep determined by PSG (r = 0.92). Moreover, the respiratory disturbance index estimated by the smartphone (smart-RDI) highly correlated with the apnea-hypopnea index (AHI) obtained by PSG (r = 0.94). The diagnostic sensitivity and specificity of the smart-RDI for diagnosing OSA (AHI ≥ 15) were 0.70 and 0.94, respectively.

CONCLUSIONS

A smartphone can be used for effectively monitoring snoring and OSA in a controlled laboratory setting. Use of this technology in a noisy home environment remains unproven, and further investigation is needed.

Automatic detection of whole night snoring events using non-contact microphone

Objective

Although awareness of sleep disorders is increasing, limited information is available on whole night detection of snoring. Our study aimed to develop and validate a robust, high performance, and sensitive whole-night snore detector based on non-contact technology.

Design

Sounds during polysomnography (PSG) were recorded using a directional condenser microphone placed 1 m above the bed. An AdaBoost classifier was trained and validated on manually labeled snoring and non-snoring acoustic events.

Patients

Sixty-seven subjects (age 52.5±13.5 years, BMI 30.8±4.7 kg/m², m/f 40/27) referred for PSG for obstructive sleep apnea diagnoses were prospectively and consecutively recruited. Twenty-five subjects were used for the design study; the validation study was blindly performed on the remaining forty-two subjects.

Measurements and Results

To train the proposed sound detector, >76,600 acoustic episodes collected in the design study were manually classified by three scorers into snore and non-snore episodes (e.g., bedding noise, coughing, environmental). A feature selection process was applied to select the most discriminative features extracted from time and spectral domains. The average snore/non-snore detection rate (accuracy) for the design group was 98.4% based on a ten-fold cross-validation technique. When tested on the validation group, the average detection rate was 98.2% with sensitivity of 98.0% (snore as a snore) and specificity of 98.3% (noise as noise).

Conclusions

Audio-based features extracted from time and spectral domains can accurately discriminate between snore and non-snore acoustic events. This audio analysis approach enables detection and analysis of snoring sounds from a full night in order to produce quantified measures for objective follow-up of patients.