Snoring as a risk factor for disease: an epidemiological survey

Automatic snoring detection using a hybrid 1D-2D convolutional neural network

Snoring, as a prevalent symptom, seriously interferes with life quality of patients with sleep disordered breathing only (simple snorers), patients with obstructive sleep apnea (OSA) and their bed partners. Researches have shown that snoring could be used for screening and diagnosis of OSA. Therefore, accurate detection of snoring sounds from sleep respiratory audio at night has been one of the most important parts. Considered that the snoring is somewhat dangerously overlooked around the world, an automatic and high-precision snoring detection algorithm is required. In this work, we designed a non-contact data acquire equipment to record nocturnal sleep respiratory audio of subjects in their private bedrooms, and proposed a hybrid convolutional neural network (CNN) model for the automatic snore detection. This model consists of a one-dimensional (1D) CNN processing the original signal and a two-dimensional (2D) CNN representing images mapped by the visibility graph method. In our experiment, our algorithm achieves an average classification accuracy of 89.3%, an average sensitivity of 89.7%, an average specificity of 88.5%, and an average AUC of 0.947, which surpasses some state-of-the-art models trained on our data. In conclusion, our results indicate that the proposed method in this study could be effective and significance for massive screening of OSA patients in daily life. And our work provides an alternative framework for time series analysis.

Automatic classification of excitation location of snoring sounds

STUDY OBJECTIVES

For surgical treatment of patients with obstructive sleep apnea-hypopnea syndrome, it is crucial to locate accurately the obstructive sites in the upper airway; however, noninvasive methods for locating the obstructive sites have not been well explored. Snoring, as the cardinal symptom of obstructive sleep apnea-hypopnea syndrome, should contain information that reflects the state of the upper airway. Through the classification of snores produced at four different locations, this study aimed to test the hypothesis that snores generated by various obstructive sites differ.

METHODS

We trained and tested our model on a public data set that comprised 219 participants. For each snore episode, an acoustic and a physiological feature were extracted and concatenated, forming a 59-dimensional fusion feature. A principal component analysis and a support machine vector were used for dimensional reduction and snore classification. The performance of the proposed model was evaluated using several metrics: sensitivity, precision, specificity, area under the receiver operating characteristic curve, and F1 score.

RESULTS

The unweighted average values of sensitivity, precision, specificity, area under the curve, and F1 were 86.36%, 89.09%, 96.4%, 87.9%, and 87.63%, respectively. The model achieved 98.04%, 80.56%, 72.73%, and 94.12% sensitivity for types V (velum), O (oropharyngeal), T (tongue), and E (epiglottis) snores.

CONCLUSIONS

The characteristics of snores are related to the state of the upper airway. The machine-learning-based model can be used to locate the vibration sites in the upper airway.

Sleeping Duration, Napping and Snoring in Association with Diabetes Control among Patients with Diabetes in Qatar

BACKGROUND

Poor glycemic control is associated with chronic life-threatening complications. Several studies have revealed that sleep status is associated with glycemic control.

AIM

to examine the association between sleep duration, quality and glycemic control among adults with diabetes.

METHODS

Data on 2500 participants aged 18-60 years were collected from the Qatar Biobank (QBB). Sleep duration and quality were assessed by a self-completed health and lifestyle questionnaire, and glycemic control was assessed using HbA1c. Logistic regression was used to assess the association between sleep duration, napping, snoring and poor glycemic control.

RESULTS

After adjusting for age and gender, sleep duration was not associated with poor glycemic control. Lack of association persisted after controlling for smoking, physical activity, education, BMI, fruit and vegetable intake, insulin and medication use. However, sleeping for long hours at night (≥8 h) had a trend in increasing the risk of poor glycemic control (OR = 1.28; 95% CI: 0.94-1.74). Napping was positively associated with poor glycemic control. After adjusting for age and gender, patients who reported "sometimes, frequently, or always" napping had more than 30% increased risk of poor control as compared to patients who reported "never/rarely" napping. Snoring was not associated with poor glycemic control among the study sample when adjusted for age and gender (p = 0.61). Other factors were found to be associated with a better glycemic control such as female, high educational and high physical activity level.

CONCLUSIONS

our results suggest that napping may be an independent risk factor for a poor glycemic control in diabetes; further investigations are required.

Use of mandibular advancement devices for the treatment of primary snoring with or without obstructive sleep apnea (OSA): A systematic review

The aim of this review was to systematically evaluate the available scientific evidence on the benefit of mandibular advancement devices (MADs) in the treatment of primary snoring (PS). From 905 initially identified articles, 18 were selected. Papers that provided indirect information regarding obstructive sleep apnea syndrome (OSAS) and/or sleep breathing disorders (SBD) were included. Information was obtained on monoblock and duoblock appliances from the selected studies. The devices were most commonly able to achieve 50%-70% of the maximum mandibular protrusion. The frequently used outcome measurements were the apnea-hypopnea index, Epworth sleepiness scale, and oxygen desaturation index, which all yielded positive post-treatment results. The most common side effects were temporomandibular joint pain and excessive salivation, which improved with time. Our findings indicated that the use of MADs, even with varying designs, improved outcomes in all the reported patient populations (PS, OSAS, and SBD). Despite the lack of studies on PS, the available evidence supports the use of MADs for treatment of PS. Snoring should be treated from a preventive and psychosocial perspective to avoid progression to more severe diseases that could have a significant medical and economic impact.

SnoreNet: Detecting Snore Events from Raw Sound Recordings

Snoring is one of the earliest symptoms of Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS). Snore detection is the first step in developing non-invasive, low-cost, and totally sound-based OSAHS analysis approaches. In this work, we propose a simple yet effective deep neural network, named SnoreNet, for detecting snores from a continuous sound recording. Without manually crafted features, SnoreNet can capture the characteristics of snores. Since snore varies in temporal length, SnoreNet combines output from multiple feature maps to detect snore. In each feature map, SnoreNet uses a set of default bounding box generated by a base length and different scales to match snores. SnoreNet adjusts the box to better locate snores and predicts a score for the presence of snore in each default bounding box. The performance of SnoreNet was evaluated on a newly collected snore pattern classes dataset, which achieves 81.82% average precision (AP).

The relationship between coffee intake, obstructive sleep apnea risk, and type 2 diabetes glycemic control, in Tabuk City, The Kingdom of Saudi Arabia: a case-control study

Objectives

The study aimed to assess the relationship between coffee intake, obstructive sleep apnea risk (OSA), and glycemic control among patients with diabetes mellitus.

Results

There were 110 patients with diabetes and 96 healthy control subjects (matched for age and sex) attending a diabetes center زinTabuk, Saudi Arabia during the period from June 2018–October 2019. Stop-Bang questionnaire was used to assess OSA risk, and Epworth Sleepiness Scale to investigate daytime sleepiness. OSA risk and daytime sleepiness were higher among patients with diabetes compared to controls (4.34 ± 1.61 vs. 2.86 ± 1.24, and 8.31 ± 4.40 vs. 6.39 ± 3.70 respectively, P < 0.5), while coffee consumption was not (4.64 ± 3.95 vs. 3.45 ± 3.06, P > 0.05). Women with diabetes were younger with short duration since the diagnosis of diabetes and consumed less coffee compared to men, P < 0.5. A negative correlation was found between coffee consumption and the duration of diabetes, while no correlation was found between coffee intake, the glycated hemoglobin, OSA risk, sex, and daytime sleepiness. Daytime sleepiness and OSA risk were commoners among patients with diabetes, they were not correlated with coffee consumption which was negatively correlated with the duration since diabetes diagnosis. Further larger multi-center studies investigating coffee intake among patients newly diagnosed with diabetes are recommended.

The Uvulopalatopharyngoplasty Operation: The Edinburgh Experience

The experience of the uvulopalatopharyngoplasty operation, performed on 24 patients for the relief of loud or heroic snoring, is presented. The operation successfully reduced the severity of snoring in 96% of patients. Postoperative complications were uncommon but included nasal regurgitation and intrapharyngeal adhesions in one patient. The role of the uvulopalatopharyngoplasty operation in the treatment of obstructive sleep apnoea is undecided but the authors do not perform this operation on such patients.

Associations of Sleep Duration and Disturbances With Hypertension in Metropolitan Cities of Delhi, Chennai, and Karachi in South Asia: Cross-Sectional Analysis of the CARRS Study

Objectives

Sleep duration and disturbances may be risk factors for hypertension. Despite the high burden of hypertension in South Asia, little is known about this relationship in this region.

Methods

We analyzed population-level cross-sectional data from the Centre for Cardiometabolic Risk Reduction in South Asia (CARRS) study that recruited representative samples of adults ≥ 20 years from three cities-Delhi, Chennai (India), and Karachi (Pakistan) during 2010-2011. We defined hypertension as self-reported treatment or measured blood pressure (BP) ≥140/90 mm Hg. Data on usual duration of sleep, insomnia, and snoring were collected using "The Sleep Habits Questionnaire" and excessive daytime sleepiness (EDS) using Epworth Sleepiness Score. Logistic and linear regression were done with hypertension and BP as outcome variables, respectively. Age, gender, education, wealth index, family history, and body mass index (BMI) were included as covariates. We used multiple imputation to account for missing variables.

Results

Prevalence of hypertension was 30.1%. The mean (SD) sleep duration was 7.3 (1.2) hours. Insomnia, snoring, and EDS were present in 13.6%, 28.7%, and 4.6%, respectively. Moderate and habitual snoring were associated with increased odds of hypertension (odds ratio [OR] = 1.18, 95% confidence interval [CI] [1.04 to 1.33] and 1.47 [1.29 to 1.67], respectively), after adjusting for covariates. Rare, occasional, and frequent insomnia were associated with increased hypertension (OR 1.41 [1.12 to 1.77], 1.39 [1.16 to 1.67], and 1.34 [1.09 to 1.65], respectively). Sleep duration and EDS were not associated with hypertension.

Conclusion

Self-reported snoring and insomnia were associated with hypertension in South Asia. This relationship needs further exploration through robust longitudinal studies in this region.

Midline Radiofrequency Tissue Reduction of the Palate for Bothersome Snoring and Sleep-Disordered Breathing: A Clinical Trial

This study is a prospective, nonrandomized clinical trial initiated to assess the safety and efficacy of radiofrequency tissue reduction of the palate for the treatment of bothersome snoring and sleep-disordered breathing. Twelve healthy volunteers with socially disruptive snoring underwent a baseline polysomnogram along with a battery of visual analog scales (VASs) to measure daytime sleepiness, snoring level, pain, and disturbances of speech and swallowing. After radiofrequency tissue reduction of the palate, they were re-evaluated with a mean follow-up after the final procedure of 15.7 ± 5.1 (mean ± SD) weeks. As rated by the bed partner, a significant reduction in the level of snoring occurred in all 12 patients, with a mean pretreatment snoring level of 8.3 ± 2.1 to a mean posttreatment snoring level of 2.1 ± 1.4. (Student t test, P < 0.0001) These patients required an average of 2.3 treatment sessions each. Nine of 12 had a reduction in snoring from a bothersome level (VAS range 5–10) to a nonbothersome level (VAS range 0–3). Daytime sleepiness as measured by the Epworth Sleepiness Scale (0–24) decreased from 10.8 ± 4.4 to 8.3 ± 4.1 ( P = 0.011). Posttreatment pain was considered absent or minimal in 11 of 12 patients and was managed with acetaminophen. No significant adverse events or complications were reported.

Sleep History and Hypertension Burden in First-Generation Chinese Migrants Settled in Italy: The CHIinese In Prato Cross-Sectional Survey

Migration flows from China are largely directed towards the South of Europe, Chinese being now the third largest overseas-born population in Italy. The aim of the study was to investigate hypertension burden and self-reported sleep disorders among 1608 first-generation Chinese migrants aged 16 to 59 years settled in Prato and recruited in a cross-sectional survey. Hypertension was defined as systolic BP ≥ 140  mm Hg and/or diastolic BP ≥ 90  mm Hg or self-reported antihypertensive treatment; potential impact of sleep disorders was analyzed by logistic regression adjusted for age, sex, marital status, education, health insurance, current smoking, parental hypertension, alcohol drinking, overweight or obesity, central obesity, diabetes, high total cholesterol, and high triglycerides. Among the 1608 participants, 21.7% were hypertensive (age-standardized prevalence 19.2%; 95% Cl: 18.5-20.0); 54% of hypertensive subjects were aware of their condition; 70% of aware hypertensive subjects received drugs, and 39% of treated subjects had blood pressure controlled. Self-reported snoring increased the risk of hypertension; when compared with no snoring, the age- and sex-adjusted OR for hypertension of snoring 3 to 6  d/week was 2.11 (95% Cl: 1.48-3.01) and 2.48 (95% Cl: 1.79-3.46) of snoring every day. When compared with a sleep duration ≤ 5  hours, subjects with sleep duration of 7  hours had reduced risk of high triglycerides (adjusted OR: 0.66; 95% Cl: 0.43-0.95).Despite a high level of awareness, low treatment rates for hypertension were observed among Chinese participants, independently of health insurance. Sleep history is to be considered in screening and prevention programs.

Sleep Dysfunction and Gastrointestinal Diseases

Sleep deprivation and impaired sleep quality have been associated with poor health outcomes. Many patients experience sleep disturbances, which can increase the risk of medical conditions such as hypertension, obesity, stroke, and heart disease as well as increase overall mortality. Recent studies have suggested that there is a strong association between sleep disturbances and gastrointestinal diseases. Proinflammatory cytokines, such as tumor necrosis factor, interleukin-1, and interleukin-6, have been associated with sleep dysfunction. Alterations in these cytokines have been seen in certain gastrointestinal diseases, such as gastroesophageal reflux disease, inflammatory bowel disease, liver disorders, and colorectal cancer. It is important for gastroenterologists to be aware of the relationship between sleep disorders and gastrointestinal illnesses to ensure good care for patients. This article reviews the current research on the interplay between sleep disorders, immune function, and gastrointestinal diseases.

Hidden Markov modelling of intra-snore episode behavior of acoustic characteristics of obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is a breathing disorder that can cause serious medical consequences. It is caused by full (apnea) or partial (hypopnea) obstructions of the upper airway during sleep. The gold standard for diagnosis of OSA is the polysomnography (PSG). The main measure for OSA diagnosis is the apnea-hypopnea index (AHI). However, the AHI is a time averaged summary measure of vast amounts of information gathered in an overnight PSG study. It cannot capture the dynamic characteristics associated with apnea/hypopnea events and their overnight distribution. The dynamic characteristics of apnea/hypopnea events are affected by the structural and functional characteristics of the upper airway. The upper airway characteristics also affect the upper airway collapsibility. These effects are manifested in snoring sounds generated from the vibrations of upper airway structures which are then modified by the upper airway geometric and physical characteristics. Hence, it is highly likely that the acoustical behavior of snoring is affected by the upper airway structural and functional characteristics. In the current work, we propose a novel method to model the intra-snore episode behavior of the acoustic characteristics of snoring sounds which can indirectly describe the instantaneous and temporal dynamics of the upper airway. We model the intra-snore episode acoustical behavior by using hidden Markov models (HMMs) with Mel frequency cepstral coefficients. Assuming significant differences in the anatomical and physiological upper airway configurations between low-AHI and high-AHI subjects, we defined different snorer groups with respect to AHI thresholds 15 and 30 and also developed HMM-based classifiers to classify snore episodes into those groups. We also define a measure called instantaneous apneaness score (IAS) in terms of the log-likelihoods produced by respective HMMs. IAS indicates the degree of class membership of each episode to one of the predefined groups as well as the instantaneous OSA severity. We then assigned each patient to an overall AHI band based on the majority vote of each episode of snoring. The proposed method has a diagnostic sensitivity and specificity between 87-91%.

HMM-based snorer group recognition for Sleep Apnea diagnosis

This paper presents an Hidden Markov Models (HMM)-based snorer group recognition approach for Obstructive Sleep Apenea diagnosis. It models the spatio-temporal characteristics of different snorer groups belonging to different genders and AHI severity levels. The current experiment includes selecting snore data from subjects, identifying snorer groups based on gender and AHI values (AHI < 15 and AHI > 15), detecting snore episodes, MFCC computation, training and testing HMMs. A set of multi-level classification rules is employed for incremental diagnosis of OSA. The proposed method, with a relatively small data set, produces results nearly comparable to any existing methods with single feature class. It classifies snore episodes with 62.0% (male), 67.0% (female) and recognizes snorer group with 78.5% accuracy. The approach makes its diagnosis decision at 85.7% (sensitivity), 71.4% (specificity) for males and 85.7% (sensitivity and specificity) for females.

The Relationship between Nocturnal Hypoxemia and Left Ventricular Ejection Fraction in Congestive Heart Failure Patients

Congestive heart failure (CHF) is a major cause of mortality and morbidity. Among patients with heart failure, sleep disordered breathing (SDB) is a common problem. Current evidence suggests that SDB, particularly central SDB, is more prevalent in patients with CHF than in the general population, but it is underdiagnosed as SDB symptoms that are less prevalent in CHF. The main aims of this study were to determine the relationship between nocturnal hypoxemia and left ventricular ejection fraction in patients with chronic heart failure. By means of echocardiography, 108 patients with left ventricular ejection fraction ≤45% were divided into mild, moderate, and severe CHF. Hypoxemia was recorded overnight in the hospital and was measured by portable pulse oximetry. In the 108 patients with CHF, 44 (40.7%) were severe, 17 (15.7%) moderate, and 47 (43.6%) mild CHF. 95 (88%) of patients with CHF had abnormal patterns of nocturnal hypoxemia suggestive of Cheyne-Stokes respiration. Ejection fraction correlated negatively with dip frequency. There was no correlation between nocturnal hypoxemia with BMI and snoring. This study confirms strong associations between sleep apnea and heart disease in patients with CHF. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

The association between obstructive sleep apnea and hypertension by race/ethnicity in a nationally representative sample

The association between obstructive sleep apnea (OSA) and hypertension by race/ethnicity has not been well characterized in a national sample. Adult participants in the 2007-2008 National Health and Nutrition Examination Survey were reviewed by self-report of sleep apnea diagnosis, snorting, gasping or stopping breathing during sleep, and snoring to derive whether OSA was probable (pOSA). Multivariable logistic regression determined whether pOSA predicted hypertension in the overall cohort, and by body mass index (BMI) group and ethno-racial strata. pOSA predicted hypertension in several groups: (1) Within BMI strata, there was a significant association among overweight individuals [odds ratio [OR], 1.82; 95% confidence interval [CI], 1.26-2.62); (2) In race/ethnicity subgroups, the association was significant among Hispanic/Latinos (OR, 1.69; 95% CI, 1.13-2.53) and whites (OR, 1.40; 95% CI, 1.07-1.84); (3) In models stratified by both race/ethnicity and BMI, pOSA predicted hypertension among overweight black/African Americans (OR, 4.74; 95% CI, 1.86-12.03), overweight whites (OR, 1.65; 95% CI, 1.06-2.57), and obese Hispanic/Latino participants (OR, 2.01; 95% CI, 1.16-3.49). A simple, self-report tool for OSA was strongly associated with hypertension, and may serve as a potential future opportunity for OSA diagnosis.

Snoring and severity of symptomatic and asymptomatic carotid stenosis: a population-based study

BACKGROUND

Obstructive sleep apnea has increasingly been linked to cardiovascular damage. More recently, the snoring component itself has been independently linked to the presence of carotid atheroma, via local arterial trauma. We aimed to identify whether a snoring history is a risk factor for carotid stenosis in individuals presenting with a TIA or ischemic stroke.

METHODS

Participants in the Oxford Vascular Study (OXVASC) were asked about their snoring history as part of an entry questionnaire. In 561 individuals with a recent TIA or stroke, who had both a complete snoring questionnaire and carotid imaging, the relationship between presence and severity of snoring and the degree of carotid artery stenosis in both the symptomatic (culprit) and asymptomatic (non-culprit) sides.

RESULTS

Of 561 participants (287 male, mean/SD age = 73.3/11.0 years), 90 (16.0%) had ≥ 50% carotid stenosis, and 154 (27.5%) snored frequently (≥ 1-2 times/week). No significant associations were identified between frequency of self-reported snoring, and the degree of culprit and non-culprit carotid vessel stenosis, or plaque morphology.

CONCLUSIONS

No significant association could be identified between a history of frequent snoring and the presence of carotid atheroma, degree of stenosis, or plaque type.

Prevalence of sleep disturbances, disorders, and problems following traumatic brain injury: a meta-analysis

BACKGROUND

Sleep is often disrupted following a traumatic brain injury (TBI), which may compromise recovery and quality of life. Prevalence rates vary widely, reflecting differences in the criteria and measures that are used to assess sleep, as well as sample differences. This meta-analysis examined the prevalence of general and specific, and formally and informally diagnosed, sleep disturbances following TBI in order to establish the nature and extent of these sequelae and their potential impact on recovery.

METHODS

Data from 21 studies, which assessed (1) sleep disturbances, regardless of type or severity, (2) diagnosed sleep disorders, and (3) specific sleep problems following TBI, were analyzed and compared to data for the general population.

RESULTS

Overall, 50% of people suffered from some form of sleep disturbance after a TBI and 25-29% had a diagnosed sleep disorder (insomnia, hypersomnia, apnea) - rates that are much higher than those seen in the general population. They were also two to four times more likely to experience problems with sleep maintenance and efficiency, nightmares, excessive sleepiness, early awakenings, and sleep walking.

CONCLUSION

Sleep disturbances are very common after TBI and have the potential to seriously undermine patient rehabilitation, recovery, and outcomes; making it important to routinely screen for such problems in order to assess both treatment needs and their potential impact on recovery and outcome.

A method to screen obstructive sleep apnea using multi-variable non-intrusive measurements

Obstructive sleep apnea (OSA) is a serious sleep disorder. The current standard OSA diagnosis method is polysomnography (PSG) testing. PSG requires an overnight hospital stay while physically connected to 10-15 channels of measurement. PSG is expensive, inconvenient and requires the extensive involvement of a sleep technologist. As such, it is not suitable for community screening. OSA is a widespread disease and more than 80% of sufferers remain undiagnosed. Simplified, unattended and cheap OSA screening methods are urgently needed. Snoring is commonly associated with OSA but is not fully utilized in clinical diagnosis. Snoring contains pseudo-periodic packets of energy that produce characteristic vibrating sounds familiar to humans. In this paper, we propose a multi-feature vector that represents pitch information, formant information, a measure of periodic structure existence in snore episodes and the neck circumference of the subject to characterize OSA condition. Snore features were estimated from snore signals recorded in a sleep laboratory. The multi-feature vector was applied to a neural network for OSA/non-OSA classification and K-fold cross-validated using a random sub-sampling technique. We also propose a simple method to remove a specific class of background interference. Our method resulted in a sensitivity of 91 ± 6% and a specificity of 89 ± 5% for test data for AHI(THRESHOLD) = 15 for a database consisting of 51 subjects. This method has the potential as a non-intrusive, unattended technique to screen OSA using snore sound as the primary signal.

Consequências do ronco não-tratado

Em alguns estudos, o ronco tem sido associado com um risco aumentado de hipertensão, doença cardíaca isquêmica e acidente vascular encefálico. Os mecanismos são desconhecidos, mas provavelmente mediados pela apneia obstrutiva do sono. Contudo, a maioria dos roncadores não tem apneia do sono. Se o ronco, por si só, aumenta o risco de doença cardiovascular, isso ainda permanece controverso.

Treatment outcomes of mandibular advancement devices in positional and nonpositional OSA patients

OBJECTIVE

The aim of the study was to investigate treatment outcome of mandibular advancement devices (MADs) for positional and nonpositional obstructive sleep apnea (OSA).

STUDY DESIGN

Forty-two positional (supine apnea-hypopnea index [AHI] > or = 2 times lateral AHI) and 30 nonpositional (supine AHI < 2 times lateral AHI) OSA patients performed 2-nights of sleep study before and after insertion of MADs.

RESULTS

The decreases in apnea severity based on a reduction in the overall and supine AHI values after MADs therapy were significantly greater for the positional OSA than nonpositional OSA group. A multiple linear regression analysis showed that decrease in overall AHI was significantly associated with being in the positional group (standardized coefficient = 0.505). Age, body mass index, gender, and time in supine position during sleep did not show significant associations with decrease in overall AHI after MAD therapy.

CONCLUSION

Our data suggest that MADs are more effective in positional OSA than nonpositional OSA patients.

Functional treatment of snoring based on the tongue-repositioning manoeuvre

Orofacial biofunction comprises muscular and physical effects, which may contribute to stabilization of the oropharyngeal airway. The tongue-repositioning manoeuvre (TRM) provides physical stabilization of the tongue and the soft palate together with, as a prerequisite, a nasal breathing mode. The aim of the present study was to evaluate the influence of a TRM treatment concept on primary snoring. The TRM was used to achieve a closed biofunctional rest position of the orofacial system and to re-educate the nasal breathing pattern. Pressure indicating oral shields were used for home exercises as a biofeedback instrument and to support nocturnal mouth closure. Treatment was undertaken on 125 consecutive primary snorers [101 males, mean age 52.4 years, range 34-75, mean body mass index (BMI) 28.1, range 18.9-38.5, and 24 females, mean age 55.2 years, range 36-70, mean BMI 26.8, range 22.7-31.9]. Bed partner ranking was performed, and snoring was judged using a 10-cm visual analogue scale (VAS). The VAS score was 8.4 (range 6-10) before treatment and decreased to 4.1 (range 0-10) after treatment [mean observation time 4.6 months (1-10)]. Analysis of variance showed a significant influence of treatment in subjects with a normal body weight (BMI 18.5-25). The data provide evidence that dynamic stabilization of the orofacial system with the TRM in conjunction with nocturnal wear of an oral shield is beneficial for reducing the symptoms in primary snorers with a normal BMI.

Sleep and metabolism: an overview

Sleep and its disorders are increasingly becoming important in our sleep deprived society. Sleep is intricately connected to various hormonal and metabolic processes in the body and is important in maintaining metabolic homeostasis. Research shows that sleep deprivation and sleep disorders may have profound metabolic and cardiovascular implications. Sleep deprivation, sleep disordered breathing, and circadian misalignment are believed to cause metabolic dysregulation through myriad pathways involving sympathetic overstimulation, hormonal imbalance, and subclinical inflammation. This paper reviews sleep and metabolism, and how sleep deprivation and sleep disorders may be altering human metabolism.

Formant analysis of breath and snore sounds

Formant frequencies of snore and breath sounds represent resonance in the upper airways; hence, they change with respect to the upper airway anatomy. Therefore, formant frequencies and their variations can be examined to distinguish between snore and breath sounds. In this paper, formant frequencies of snore and breath sounds are investigated and automatically grouped into 7 clusters based on K-Means clustering. First, formants clusters of breath and snore sounds of all subjects were investigated together and their union were calculated as the most probable ranges of the formants. The ranges for the first four formants which span the main frequency components of breath and snore sounds were found to be [20-400]Hz, [270-840]Hz, [500-1380]Hz and [910-1920]Hz. These ranges were then used as priori information to recalculate the formants of snore and breath sounds separately. Statistical t-test showed the 1(st) and 3(rd) formants to be the most characteristic features in distinguishing the breath and snore sounds from each other.

Snoring and systemic hypertension--an epidemiological study

The prevalence of snoring, overweight and systemic hypertension was estimated in a random sample of 4,064 Swedish men, aged 30-69 years. Of the responders, 15.5% complained of habitual snoring and 29.6% of occasional snoring. Although there was an age-related increase in the prevalence of snoring up to 60 years, habitual snoring was found to be mainly related to body mass index (BMI) (p less than 0.0001) but not to age. Altogether 299 men (9.3%) reported hypertension, 21.5% of whom were habitual snorers, compared with 14.9% of the non-hypertensives (p less than 0.01). The hypertensives were also more often overweight. Logistic multiple regression analyses showed that among subjects 40-49 years old there was an average increase in the predicted prevalence of hypertension from 6.5% among non-snorers to 10.5% of habitual snorers in the same weight group. For the whole study population, however, the increase was mainly dependent on age and BMI. Thus, the importance of habitual snoring for the prevalence of hypertension differs in various age groups.

Circadian rhythm of autonomic activity in patients with obstructive sleep apnea syndrome

BACKGROUND AND HYPOTHESIS

Although the immediate effects of sleep apnea on hemodynamics and the neurological system have been studied, little is known about the circadian rhythm of heart rate variability in patients with obstructive sleep apnea syndrome (OSAS). The purpose of the present study was to investigate the effects of sleep apnea on the autonomic activity during daytime, which may play some role in the pathogenesis of cardiovascular complications in OSAS.

METHODS

We studied 18 middle-aged male patients with OSAS and 10 age-matched control subjects. Patients with OSAS were classified according to the severity of OSAS: patients with an apnea index (AI) < 20 were considered to have mild OSAS (Group 1, n = 8) and patients with an AI > or = 20 were considered to have severe OSAS (Group 2, n = 10). Heart rate variability was calculated from the 24-h ambulatory electrocardiograms by the Fourier transformation. Power spectra were quantified at 0.04-0.15 Hz [low frequency power (LF)ln(ms2)] and 0.15-0.40 Hz [high frequency power (HF)ln(ms2)]. The HF component and the ratio of LF to HF were used as indices of the parasympathetic and sympathetic activity, respectively.

RESULTS

The circadian rhythms of the LF, HF, and LF/HF ratio differed significantly in Group 2 compared with Group 1 and control subjects (p < 0.05). Hypertension (> 160/95 mm Hg) was found in 7 (70.0%) of 10 patients in Group 2, and in 1 (12.5%) of 8 patients in Group 1. Echocardiographic evidence of left ventricular hypertrophy (LVH) (an interventricular septal thickness or a left ventricular posterior wall thickness > or = 12 mm) was found in 3 (30.0%) of 10 patients in Group 2, and in 1 (12.5%) of 8 patients in Group 1. The mean HF from 4 A.M. to 12 noon was significantly lower in Group 2 than in Group 1 and the control group, and it correlated significantly with the lowest nocturnal SaO2 (r = 0.58, p < 0.05). The mean LF/HF ratio during the same period was significantly higher in Group 2 than in Group 1 and the control group, and it correlated significantly with total time of the nocturnal oxygen saturation < 90% (r = 0.64, p < 0.005) and the lowest nocturnal SaO2 (r = 0.56, p < 0.05). Ventricular tachycardia was found in the early morning in one patient, ST-T depression in two patients, and sinus arrest in two patients in Group 2.

CONCLUSION

These findings suggest that sleep-disordered breathing associated with severe oxygen desaturation might influence heart rate variability not only during sleep but also during daytime. OSAS per se might contribute to altered circadian rhythm in autonomic activity leading to the development of cardiovascular diseases.

Obstructive sleep apnoea/hypopnoea syndrome and hypertension

The obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is a common disorder, affecting around 2-4% of the middle-aged population. There is a strong association between OSAHS and hypertension, based on animal, large epidemiological and interventional studies. The epidemiological studies have shown a dose-response relationship between apnoea/hypopnoea index (AHI) and the risk of developing hypertension. Different mechanisms may have a role in the process of elevated blood pressure in OSAHS. Sympathetic activity is increased in OSAHS patients during sleep and wakefulness. This increase in sympathetic activity is probably due to activation of baroreflexes and chemoreflexes by frequent arousals and hypoxaemia a result of apnoea or hypopnoea events. Continuous positive airway pressure (CPAP) has been shown to reduce sympathetic stimulation and blood pressure in OSAHS patients. Altered endothelial function may also have a role in the pathogenesis of hypertension in OSAHS subjects. Reduction of nitric oxide (NO) production and increase in the formation of free radicals may be responsible for the impairment of the vasodilatation of micro-vasculature in these subjects as a result of hypoxaemia. It has been shown that effective CPAP therapy has a reversible effect on endothelial dysfunction.

Investigation of sequential properties of snoring episodes for obstructive sleep apnoea identification

In this paper, 'snore regularity' is studied in terms of the variations of snoring sound episode durations, separations and average powers in simple snorers and in obstructive sleep apnoea (OSA) patients. The goal was to explore the possibility of distinguishing among simple snorers and OSA patients using only sleep sound recordings of individuals and to ultimately eliminate the need for spending a whole night in the clinic for polysomnographic recording. Sequences that contain snoring episode durations (SED), snoring episode separations (SES) and average snoring episode powers (SEP) were constructed from snoring sound recordings of 30 individuals (18 simple snorers and 12 OSA patients) who were also under polysomnographic recording in Gülhane Military Medical Academy Sleep Studies Laboratory (GMMA-SSL), Ankara, Turkey. Snore regularity is quantified in terms of mean, standard deviation and coefficient of variation values for the SED, SES and SEP sequences. In all three of these sequences, OSA patients' data displayed a higher variation than those of simple snorers. To exclude the effects of slow variations in the base-line of these sequences, new sequences that contain the coefficient of variation of the sample values in a 'short' signal frame, i.e., short time coefficient of variation (STCV) sequences, were defined. The mean, the standard deviation and the coefficient of variation values calculated from the STCV sequences displayed a stronger potential to distinguish among simple snorers and OSA patients than those obtained from the SED, SES and SEP sequences themselves. Spider charts were used to jointly visualize the three parameters, i.e., the mean, the standard deviation and the coefficient of variation values of the SED, SES and SEP sequences, and the corresponding STCV sequences as two-dimensional plots. Our observations showed that the statistical parameters obtained from the SED and SES sequences, and the corresponding STCV sequences, possessed a strong potential to distinguish among simple snorers and OSA patients, both marginally, i.e., when the parameters are examined individually, and jointly. The parameters obtained from the SEP sequences and the corresponding STCV sequences, on the other hand, did not have a strong discrimination capability. However, the joint behaviour of these parameters showed some potential to distinguish among simple snorers and OSA patients.

Ronco habitual e apnéia obstrutiva observada em adultos: estudo de base populacional, Pelotas, RS

OBJETIVO: Estimar a prevalência de ronco habitual e apnéia obstrutiva observada e fatores associados. MÉTODOS: Estudo transversal com amostra representativa de 3.136 adultos, com 20 anos ou mais, residentes em Pelotas, Rio Grande do Sul, em 2005. Informações sobre os desfechos e variáveis demográficas, socioeconômicas, comportamentais e antropométricas foram coletadas por meio de questionário. A análise estatística bruta e ajustada foi realizada utilizando-se teste exato de Fisher ou qui-quadrado de tendência linear e regressão de Poisson, respectivamente. RESULTADOS: A prevalência encontrada de ronco habitual foi de 50,5% (IC 95%: 48,1;52,8) e de apnéia obstrutiva de 9,9% (IC 95%: 8,7;11,2). Na análise ajustada, o relato de ronco foi maior nos homens (Razão de Prevalências - RP=1,25; IC 95%: 1,16;1,34), nos idosos (RP=1,62; IC 95%: 1,46;1,80), nos tabagistas (RP=1,15; IC 95%: 1,07;1,25), nos alcoolistas (RP=1,17; IC 95%: 1,03;1,31) e nos obesos (RP 1,71, IC95% 1,55;1,88). O relato de apnéia obstrutiva foi maior nos homens (RP=2,05; IC 95%: 1,67;2,52), nos idosos (RP=2,23; IC 95%: 1,64;3,03), nos tabagistas (RP=1,60; IC 95%: 1,25;2,05) e nos obesos (RP=2,61; IC 95%: 1,97;3,47). CONCLUSÕES: Ronco habitual e apnéia obstrutiva foram sintomas comuns na população estudada. Fatores de risco conhecidos como sexo masculino e idade entre quarta e quinta décadas de vida não são modificáveis. Entretanto, tabagismo, alcoolismo e obesidade também associados aos desfechos, devem ser identificados e tratados na população geral.

Obstructive sleep apnea and type 2 diabetes: interacting epidemics

Type 2 diabetes is a major public health concern with high morbidity, mortality, and health-care costs. Recent reports have indicated that the majority of patients with type 2 diabetes also have obstructive sleep apnea (OSA). There is compelling evidence that OSA is a significant risk factor for cardiovascular disease and mortality. Rapidly accumulating data from both epidemiologic and clinical studies suggest that OSA is also independently associated with alterations in glucose metabolism and places patients at an increased risk of the development of type 2 diabetes. Experimental studies in humans and animals have demonstrated that intermittent hypoxia and reduced sleep duration due to sleep fragmentation, as occur in OSA, exert adverse effects on glucose metabolism. Based on the current evidence, clinicians need to address the risk of OSA in patients with type 2 diabetes and, conversely, evaluate the presence of type 2 diabetes in patients with OSA. Clearly, there is a need for further research, using well-designed studies and long-term follow-up, to fully demonstrate a causal role for OSA in the development and severity of type 2 diabetes. In particular, future studies must carefully consider the confounding effects of central obesity in examining the link between OSA and alterations in glucose metabolism. The interactions among the rising epidemics of obesity, OSA, and type 2 diabetes are likely to be complex and involve multiple pathways. A better understanding of the relationship between OSA and type 2 diabetes may have important public health implications.

Risk factors and correlates of snoring and observed apnea

BACKGROUND AND PURPOSE

Risk factors and correlates of snoring and observed apnea in the population are not well known. This study aimed to assess risk factors and correlates of snoring and observed apnea.

METHODS

Parents and grandparents of students from 20 randomly selected primary schools in urban and rural areas of Kirikkale, Turkey were asked about respiratory diseases, psychological distress and sleep-related disorders, using the Respiratory Questionnaire, Hospital Anxiety and Depression (HAD) scale and Sleep Questionnaire, respectively, which were returned by their children.

RESULTS

Out of 13,225 parents and grandparents of primary school students 12,270 returned the questionnaires, for an overall response rate of 92.7%. Snoring and the observed apnea were more prevalent among subjects from rural than those from urban areas (52.6% vs. 46.6%, odds ratio (OR): 1.2, p<0.001 and 16.2% vs. 10.1%, OR: 1.7, p<0.001, respectively). Exposure to biomass smoke and smoking were associated with an increased risk of snoring and observed apnea, after adjusting for gender, age, body mass index, income and education in the multivariate linear model. In all subjects, increases in performance ability, daytime sleepiness, psychological distress and dyspnea scores observed in categories indicating increases in snoring intensity and observed apnea frequency constituted a trend but did always not reach statistical significance. Lastly, prevalence of traffic accidents, falling asleep at the wheel and morning headaches increased with the increments of snoring intensity and apnea frequency.

CONCLUSIONS

Exposure to biomass smoke in rural areas may account for the higher prevalence of snoring and observed apnea. Snoring intensity and observed apnea frequency may increase prevalence of traffic accidents along with many unfavorable symptoms.

Obstructive sleep apnea and cardiovascular risk

Obstructive sleep apnea (OSA) is a form of sleep disordered breathing characterized by episodes of apnea (during sleep) lasting at least 10 seconds per episode. The apneic periods are associated with arterial hypoxemia and disruption of normal sleep as a result of awakenings. It is increasingly being recognized that OSA is a public health hazard and there is increasing evidence that it is associated with an increase in morbidity (and possibly mortality). Patients with OSA also utilize the healthcare resources at higher rates than control patients long before their diagnosis is confirmed. Early recognition of this condition may lead to earlier treatments (eg, nasal CPAP) with reduction of the risk of cardiovascular diseases such as hypertension, ischemic heart disease, arrhythmias, platelet activation and pulmonary hypertension.

An efficient method for snore/nonsnore classification of sleep sounds

A new method to detect snoring episodes in sleep sound recordings is proposed. Sleep sound segments (i.e., 'sound episodes' or simply 'episodes') are classified as snores and nonsnores according to their subband energy distributions. The similarity of inter- and intra-individual spectral energy distributions motivated the representation of the feature vectors in a lower dimensional space. Episodes have been efficiently represented in two dimensions using principal component analysis, and classified as snores or nonsnores. The sound recordings were obtained from individuals who are suspected of OSAS pathology while they were connected to the polysomnography in Gülhane Military Medical Academy Sleep Studies Laboratory (GMMA-SSL), Ankara, Turkey. The data from 30 subjects (18 simple snorers and 12 OSA patients) with different apnoea/hypopnea indices were classified using the proposed algorithm. The system was tested by using the manual annotations of an ENT specialist as a reference. The accuracy for simple snorers was found to be 97.3% when the system was trained using only simple snorers' data. It drops to 90.2% when the training data contain both simple snorers' and OSA patients' data. (Both of these results were obtained by using training and testing sets of different individuals.) In the case of snore episode detection with OSA patients the accuracy is 86.8%. All these results can be considered as acceptable values to use the system for clinical purposes including the diagnosis and treatment of OSAS. The method proposed here has been used to develop a tool for the ENT clinic of GMMA-SSL that provides information for objective evaluation of sleep sounds.

Application of the Kushida morphometric model in patients with sleep-disordered breathing

The morphometric model is a useful screening test to investigate the possibility of OSAS in patients during initial office visits.

AIM

To evaluate the clinical applicability of the Kushida morphometric model in a sample of patients with sleep-disordered breathing, and to define a cutoff value to differentiate patients with mild, moderate and severe apnea.

METHOD

A sample of 80 patients with sleep respiratory disorder was studied. Patients were aged between 18 and 75 years, of both genders and had been submitted previously to polysomnography. The model cutoff value to distinguish between patients with or without apnea is 70.

RESULTS

In this sample, the model cutoff value in all four groups was less than 70. It was impossible to establish a cutoff value according to the gravity of the condition, due to the proximity and the nonlinear increase in the values presented by the nonapneic group and those with mild and moderate apnea.

CONCLUSION

The Kushida morphometric model can be applied in clinical practice to a selected sample and it was impossible to establish a cutoff value to separate patients with obstructive sleep apnea-hypopnea syndrome according to severity.

Role of sleep-wake cycle on blood pressure circadian rhythms and hypertension

Stages of different depth characterize the temporal organization of sleep. Each stage exerts an effect on blood pressure (BP) regulation and contributes to its 24-h variation. The main determinant of the circadian influences of sleep and wakefulness on BP is the daytime sympathetic and nighttime parasympathetic prevalence, but many other physiologic mechanisms known either to induce sleep or determine arousal may play an important role in the mediation of sleep influences on BP. Alteration of one or more of such mechanisms may be reflected in altered circadian BP rhythms. Sleep- and arousal-related mechanisms and phenomena that affect circadian BP rhythms include neurohumoral sleep factors (arginine vasopressin, vasoactive intestinal peptide, somatotropin, insulin, steroid hormones and metabolites, and serotonin among others) and waking factors (corticotropin-releasing factor, adrenocorticotropin, thyrotropin-releasing hormone, endogenous opioids, and prostaglandin (E(2))). Pathologic respiratory variations (sleep-disordered breathing) and insomnia are major causes of the sleep-related alteration of the circadian BP profile, including loss of the expected normal decline in BP by 10-20% from the daytime level. A great number of medical disorders can cause insomnia, but objective sleep studies have been performed only in a minority of them. Overall, the sleep-related pathophysiological mechanisms actually involved in causing altered circadian BP rhythms in different normotensive and hypertensive conditions are not completely understood. In any case, changes in the circadian BP rhythm are known to be strongly related to one's risk of cardiovascular morbidity and mortality, thus representing strong prognostic indicators worthy of further investigation.

Relation of habitual snoring with components of metabolic syndrome in Korean adults

AIMS

To examine the association between habitual snoring and components of the metabolic syndrome in Korean adults. Whether these associations are independent of obesity was also explored.

METHODS

Four thousand five hundred and six men and 5041 women aged 40-69 years from the Korean Health and Genome Study were examined. Information of snoring frequency was obtained by a questionnaire and components of the metabolic syndrome were measured.

RESULTS

There was a clear dose-response relationship between the increasing frequency of snoring and the higher prevalence of each component of the metabolic syndrome (P<0.001). After adjustment for age, abdominal obesity, and the other metabolic components, hypertension was significantly associated with a 1.2-fold excess of habitual snoring in both men (P<0.05) and women (P<0.05). The association of habitual snoring with hypertension was unaltered by obesity. Regardless of the presence or absence of abdominal obesity, there was an increase in the prevalence of habitual snoring as the number of metabolic abnormalities increased.

CONCLUSIONS

Habitual snoring is associated with hypertension independent of obesity. While the relationship between habitual snoring and obesity is well recognized, characterization of the role of the other components of the metabolic syndrome as a cause or result of habitual snoring warrants a further study.

Radiofrequency tissue volume reduction of the soft palate and UPPP in the treatment of snoring

The purpose of this study was to evaluate the efficiency of radiofrequency tissue volume reduction (RFTVR) and uvulopalatopharyngoplasty (UPPP) in the treatment of snoring in a prospective clinical trial of 79 patients consecutively undergoing surgery for snoring. Seventy-nine patients with primary snoring or mild OSAS (obstructive sleep apnea syndrome) were enrolled in this clinical trial (66 males and 13 females). According to the anatomical findings (the size of the tonsils and uvula), the patients underwent UPPP/TE of the RFTVR of the soft palate. Forty-seven patients had UPPP/TE (age 45.81+/-12.11 years; median AHI: 8; range 1-29). Thirty-two patients were treated with RFTVR of the soft palate (age 48.10+/-10.92; median AHI: 5.0; range 0-26). The average number of treatments was 2.2. All patients underwent preoperative polysomnography to exclude severe OSAS. Pre- and postoperative snoring scores were evaluated from the patients with bed partners. Postoperative follow-up data were collected at a median of 4 months after treatment; 85.1% of the UPPP group and 53.1% of the RFTVR group underwent postoperative polysomnography. Subjective snoring scores of all study participants were evaluated. Preoperatively, there was no statistically significant difference of subjective symptoms, age and BMI between the two groups. The snoring scores improved statistically significantly in both groups (P <0.001 in the UPPP group; P =0.001 in the RFTVR group). After UPPP/TE snoring improved in 37 patients (78.7%), and 29 (61.7%) thereof were free of bothersome snoring; no change was found in 9 patients (19.2%), and 1 (2.1%) worsened. In the RFTVR group, snoring improved in 15 (46.9%), and 9 (28.1%) thereof were free of bothersome snoring; no change was found in 13 patients (50%), and 1 worsened (3.1%). Preoperative AHI was statistically higher (P =0.016) and mean minimal oxygen saturation significantly lower (P =0.002) in the UPPP group. In the UPPP group AHI and HI showed statistically significant improvement postoperatively (P =0.025 and P =0.034, respectively). After RFTVR, no statistically significant change of AHI, HI or oxygen saturation was found. Besides limited mucosal erosions (15%) after RFTVR and foreign body sensations (<10%) after UPPP/TE, no side effects were observed. The success rate of RFTVR of the soft palate is lower compared to the more invasive technique of UPPP. Due to its minimally invasive character, RFTVR is suitable as first-step treatment for snoring, but patients should be counseled about possible success rates and different treatment options.

Oral Appliance Therapy for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive, complete or partial closure of the upper airway during sleep, resulting in sleep fragmentation and oxygen desaturation. The disorder causes significant morbidity, particularly in terms of impairment of daytime functioning and the impact this has on quality of life. There is also evidence that links OSA to long-term cardiovascular morbidity, including hypertension, myocardial infarction, and stroke, and increased risk of motor vehicle accidents. There is clear evidence that effective treatment of OSA provides major benefit to patients. Nasal continuous positive airway pressure (CPAP) is the current treatment of choice, but its cumbersome nature makes tolerance and compliance less than optimal. This gives rise to the need for other alternatives that are equally effective, but more tolerable. There is growing interest in the use of oral appliances to treat snoring and OSA. The rationale is that advancement of the mandible and tongue impacts positively on upper airway caliber and function. There are many such types of appliances, and they have potential advantages over CPAP in that they are unobtrusive, make no noise, do not need a power source, and are potentially less costly. There is a growing evidence base to support the use of oral appliances in the management of OSA. Recent evidence from randomized controlled trials indicates that oral appliance therapy is effective in controlling OSA in up to 50% of patients, including some patients with more severe forms of OSA. This is associated with a significant improvement in symptoms, including snoring and daytime sleepiness. This evidence is strong for short term, and emerging for long-term treatment of OSA with oral appliances. Whilst direct comparisons with CPAP indicate the superiority of CPAP overall, similar outcomes between the two treatments appear to be achieved in a substantial subgroup of patients. Patient acceptance has, in general, been in favor of oral appliances. Notwithstanding the expanding role of oral appliance therapy, there are a number of limitations that are yet to be overcome. Key issues include the inability to reliably predict treatment outcome, the apparent need for an acclimatization period to attain maximal efficacy of treatment, uncertainty about selection of the appropriate 'dosage' of mandibular advancement required to control OSA in the individual patient, uncertainty about the influence of appliance design on treatment outcome and adverse effects, adherence to treatment, and potential long-term complications of therapy. These issues require resolution before oral appliance therapy can surpass CPAP as first-line treatment for OSA.