Simulated Snoring Research Articles

Assessment of simulated snoring sounds with artificial intelligence for the diagnosis of obstructive sleep apnea

BackgroundPerforming simulated snoring (SS) is a commonly used method to evaluate the source of snoring in obstructive sleep apnea (OSA). SS sounds is considered as a potential biomarker for OSA. SS sounds can be easily recorded, which is a cost-effective method for prescreening purposes. ObjectiveThis study aimed to validate the performance of artificial intelligence (AI) models using SS sounds for OSA diagnosis. MethodsAll participants underwent full-night polysomnography (PSG) monitoring at the sleep center. SS sounds of the participants were recorded during the laryngoscopy procedure. The audio data were processed via Python, and relevant features were extracted. OSA diagnostic models were developed using three machine learning (ML) algorithms and one deep learning (DL) algorithm. The diagnostic performance was evaluated by multiple indicators. ResultsA total of 465 participants were included. For the support vector machine algorithm, the accuracy values at apnea-hypopnea index (AHI) levels of 5, 15, and 30 per hour were 0.914, 0.887, and 0.807, respectively. For the K-nearest neighbor algorithm, the accuracy values at AHI levels of 5, 15, and 30 per hour were 0.896, 0.872, and 0.756, respectively. For the random forest algorithm, the accuracy values at AHI levels of 5, 15, and 30 per hour were 0.905, 0.881, and 0.804, respectively. For the audio spectrogram transformer algorithm, the accuracy values at AHI levels of 5, 15, and 30 per hour were 0.926, 0.887, and 0.830, respectively. ConclusionsOur study demonstrates that DL models can effectively screen and identify OSA with commendable performance. In addition, the identification ability of the DL models was better than that of any of the ML models.

Comparison of Muller’s maneuver simulated snoring and sleep endoscopy according to VOTE classification in sleep apnea patients

Comparison of Muller’s maneuver simulated snoring and sleep endoscopy according to VOTE classification in sleep apnea patients

Depth-dependent changes of obstruction patterns under increasing sedation during drug-induced sedation endoscopy: results of a German monocentric clinical trial.

Drug-induced sedation endoscopy (DISE) and simulated snoring (SimS) can locate the site of obstruction in patients with sleep-disordered breathing (SDB). There is clinical evidence for a change in collapsibility of the upper airway depending on the depth of sedation. So far, a dose-response relationship between sedation and collapsibility has not been demonstrated. DISE and SimS were performed in 60 consecutive patients with SDB under monitoring of depth of sedation by BiSpectral Index® (BIS). Initially, SimS was conducted followed by DISE using bolus application of propofol. Sedation was performed up to a sedation level representing slow wave sleep (BIS=40). The collapsibility of the upper airway was documented at decreasing sedation levels by an identical pictogram classification. For all levels and patterns of obstruction, a dose-dependent increase in the collapsibility of the upper airway was detected. A maximum collapsibility was achieved at sedation levels representing slow wave sleep. The collapsibility during SimS corresponded to light sleep stages and did not cover slow wave sleep. A dose-dependent change of patterns of obstructions can be observed during DISE under BIS monitoring indicating sedation depth. The obtained patterns of obstruction during DISE and SimS should thus be interpreted with regard to the sedation depth.

Survey of otorhinolaryngologists on their clinical examinations performed in patients with suspected sleep-disordered breathing

There is currently no standardized ear, nose, and throat (ENT) clinical examination for patients with sleep-disordered breathing (SDB). As a result, there are large inter-individual differences in the examinations due to an inadequate estimation of the relevance of certain anatomic sites. We aimed to identify which examinations/dynamic tests are considered most relevant by German ENT physicians. A questionnaire was designed, evaluating 23 anatomic sites/dynamic tests of the upper aero-digestive tract. The questionnaire was sent to all German ENT departments (n = 153), including universities and other tertiary or secondary referral centers, by postal mail. In addition, almost all private ENT specialists registered with the German professional association (n = 2496) were contacted via e-mail. Participants assessed how often they examined the sites/dynamic tests, subjective importance, and the impact on the therapeutic procedure. A mean score of relevance (mSOR) was generated (minimum score 1; maximum score 75) from these three items. The response rate for hospitals was 58.8 %; while, it was 4.1 % for ENT specialists in private practice. Therefore, the total response rate was 7.3 %. Of the 23 assessed items, some showed a high overall relevance, such as the tonsils (mSOR 64.75), webbing (mSOR 58.14), uvula (mSOR 55.12), or tongue base (mSOR 53.99). Other examinations, such as simulated snoring (mSOR 19.34) or the Mueller maneuver (mSOR 18.98), were estimated as less relevant. Our data reflect the assessment of German otorhinolaryngologists on the clinical examination of SDB patients. The results should be considered as a basis for compiling a standardized procedure.

Drug-induced sleep endoscopy and simulated snoring in patients with sleep-disordered breathing: agreement of anatomic changes in the upper airway.

Drug-induced sleep endoscopy (DISE) and simulated snoring (SimS) are performed as part of the diagnostic procedure in patients with suspected sleep-disordered breathing (SDB). Despite both techniques frequently performed, they have rarely been evaluated yet in terms of agreement of the obtained results. Both diagnostic procedures were performed consecutively in 40 patients with SDB and documented identically. The obtained data were analysed with respect to the agreement of both procedure at different levels of the oropharynx as well as different patterns of obstruction and vibration. The anterior-posterior collapsibility of the soft palate/uvula revealed a moderate agreement between SimS and DISE (κ = 0.42; 95 % CI 0.22-0.63). The dorsal shift of the tongue base agreed moderate for patients with an AHI below 10 (κ = 0.47) and above 25 (κ = 0.44) between SimS ad DISE. The lateral and circular pharyngeal collapsibility at velum and tongue base level did not agree between SimS and DISE, was higher for DISE and could be partially reversed by mandibular protrusion. Collapse patterns of the soft palate and uvula can be induced by SimS and resemble the patterns induced by DISE. The dorsalization of the tongue base can be simulated to a lower extent by SimS. Lateral and circular patterns of collapse at the upper and lower oropharynx induced by DISE do not seem to be simulated by SimS. SimS seems to be an additional method to screen the collapsibility of the soft palate and uvula prior to DISE.

Abstract 503: A Within-Subject Repeatability Coefficient Assessment of Snoring on Carotid Artery Velocities

Objectives: Vascular surgeons use duplex ultrasound (US) to evaluate carotid stenoses as a means to determine stroke risk. An under-appreciated risk factor is Obstructive Sleep Apnea (OSA). Although the mechanism is unknown, preliminary studies suggest snoring may play a role. The goals were to determine 1) daily carotid artery velocity variability within subjects and 2) the effect of simulated snoring on carotid artery velocities. Methods: 44 bilateral carotid artery US exams were performed on 11 subjects by 2 RVTs (4 exams/subject, 7 subjects/RVT A, 4 subjects/RVT B). Steps were taken to ensure measurements were made at identical sites under similar parameters for subsequent exams. PSV and EDV were measured at 8 locations at rest and during a simulated snore. For each location, limits of agreement was used to calculate PSV and EDV repeatability coefficients, which are the limits within which 95% of the differences will lie for two measurements made on the same subject. Repeatability coefficients were then used to determine significance for observed velocity changes in carotid arteries with and without stenosis during simulated snoring, at 3 locations. They were also used to assess velocity variability in CEA candidates. All US exams were performed in an IAC vascular testing accredited laboratory by RVTs. Results: Repeatability coefficients for RVT A ranged from 26 to 40cm/s for PSV and 11 to 20cm/s for EDV. For RVT B they ranged from 30 to 65 and 8 to 19cm/s for PSV and EDV, respectively. Maximum values occurred in the ICA ostia and ECA for RVT A, and in the ICA ostia and proximal for RVT B. In non-stenosed arteries, snoring most frequently caused a change in the PSV of the proximal ICA where it occurred in 17% of the arteries (4/24). However, the effect of snoring was greatest in stenosed arteries. In 75% of these arteries (6/8) there was a significant velocity change. 38% of proximal ICA PSVs and EDVs were affected. Conclusion: Repeatability coefficients can be used to determine significant changes in carotid artery velocities within diagnostic stenosis categories as measured by US. There is a possible connection between snoring, carotid velocities and stenosis which warrants further investigation to determine if it is part of the mechanism by which OSA increases stroke risk.

Impact of Chronic Simulated Snoring on Carotid Atherosclerosis in Rabbits

Background and PurposeChronic simulated snoring was induced in rabbits to determine the impact of snoring on the development of atherosclerosis.MethodsThe pressure wave of induced snoring at the carotid bifurcation of rabbits was acquired by gently pressing the airway. This wave was then simulated using custom-made mechanical devices. Twelve rabbits were used in this study, seven of which were assigned to the experimental group and the remaining five formed the control group. All of the rabbits were raised on a 1% high-cholesterol diet. Either working or sham devices were positioned at the ventral center of the neck in each rabbit. At the end of a 2-month observation period, all of the rabbits were sacrificed by perfusion fixation, the carotid arteries harvested, and the carotid atherosclerosis histology reviewed.ResultsAll of the rabbits survived to the end of the experimental period. Blood sampling revealed the presence of hypercholesterolemia in both groups, with no significant difference between them. The presence and degree of atherosclerosis did not differ significantly between the groups.ConclusionsThe findings of this study show the feasibility of making a chronic simulated snoring rabbit model. However, the causative role of snoring in carotid atherosclerosis was not detected in this animal study.

The upper airway in sleep‐disordered breathing: A clinical prediction model

An examination of the upper airway in patients with suspected sleep disordered breathing (SDB) is recommended prior to nighttime polysomnography (PSG) despite a reported low predictive value of those examinations. The aim of this study was to evaluate the data of the clinical examination and to create a clinical prediction model. Retrospective cohort study. A recently introduced method of dynamic examination of the upper airway during simulated snoring (SS) in awake patients is conducted in patients with suspected SDB. Clinical parameters, body mass index (BMI), and the Epworth sleepiness scale (ESS) scores of 622 patients were included in a clinical prediction model and correlated to the apnea-hypopnea index (AHI). A correlation was detected between the AHI and alterations of the upper airway during SS, BMI, and ESS score. A clinical prediction model including clinical data, BMI, and ESS score revealed a high sensitivity but low specificity predicting the nocturnal AHI: calculated AHI = tonsil size x 2.648 + uvula size x 3.776 + dorsal movement during SS x 2.842 + collapse at tongue base level during SS x 4.769 + BMI x 0.609 + ESS score x 1.177 - 27.685. The dynamic examination of the upper airway during SS in awake patients in combination with clinical data, the BMI, and ESS score is an easy-to-perform screening procedure prior to nighttime PSG and might support the otorhinolaryngologic diagnostic approach in patients with suspected SDB.

Frequency analysis of snoring sounds during simulated and nocturnal snoring

Despite several ways of investigation, such as clinical examination, drug-induced sleep endoscopy and pressure measurement of the upper airway, it is still difficult to locate the site of snoring exactly. Frequency analysis of snoring sounds is described as a promising diagnostic tool. The aim of the study was to examine simulated snoring under conditions awake, record the produced snoring sounds and compare those sounds with nocturnal snoring. A total of 50 snoring male patients were examined clinically by flexible nasal endoscopy and simulated snoring under conditions awake, and the simulated snoring sounds were recorded. Additionally, nocturnal snoring sounds were recorded during nighttime polysomnography. Snoring events were analyzed by fast-fourier-transformation and the intensity peaks 1-5 were evaluated. Rhythmic and non-rhythmic snoring events were distinguished depending on present obstructive apneas. Clinical and polysomnographical data were correlated with the results of the frequency analysis of the snoring sounds. Simulated snoring sounds revealed a low frequency of 200 Hz in intensity peaks 1 and 2 with an increase up to 3,000 Hz in peaks 3-5. Similar frequency patterns were detected in rhythmic nocturnal snoring. Non-rhythmic snoring events revealed frequency patterns between 2,000 and 3,000 Hz in all five intensity peaks. Simulated snoring resembles rhythmic nocturnal snoring with low-frequency intensity peaks, whereas non-rhythmic snoring revealed high frequencies. The examination during simulated snoring and frequency analysis of snoring sounds might contribute in locating the pathogenesis of snoring.

The Prognostic Value of Simulated Snoring in Awake Patients With Suspected Sleep-Disordered Breathing: Introduction of a New Technique of Examination

A clinical examination of the upper airway in patients with suspected sleep-disordered breathing (SDB) is frequently performed before nighttime polysomnography. In recent years, the findings of "static" examinations, such as dorsalization of the tongue base, the Malampatti index, and Mueller maneuver, have been determined to be of low predictive value. We developed a new method of "dynamic" examination of the upper airway during simulated snoring in awake patients and analyzed the method in terms of the predictive value for suspected SDB. N/A PATIENTS: One hundred thirty-one patients were examined prior to night-time polysomnography, and the results were correlated with the apneahypopnea-index (AHI). N/A RESULTS: A significant correlation was detected between an increased dorsal movement of the tongue base, as well as with pharyngeal collapse at the level of the tongue base and the AHI. Pharyngeal collapse at the level of the velum did not correlate with the AHI. The patient's body position during simulated snoring did not influence the results. The "static" examinations, such as the dorsalization of the tongue base, tonsil size, Malampatti index, and Mueller maneuver, did not correlate with the AHI. Patients with a high degree of pharyngeal collapse at the level of the tongue base, in combination with dorsal movement of the tongue base during simulated snoring, revealed a probability of 75% to have an AHI more than 10 and of 92% for an AHI more than 5. The "dynamic" examination of the upper airway under simulated snoring in awake patients is an easy-to-perform method to predict the probability of SDB prior to nighttime polysomnography.

Effect of air leak on the performance of auto-PAP devices: a bench study

Automatic positive airway pressure (auto-PAP) devices, used in the treatment of patients with obstructive sleep apnea (OSA), may not function optimally in the presence of an air leak. We set out to determine the magnitude of air leak that prevents auto-PAP devices from responding to respiratory events of OSA in a bench model. We simulated apnea, flow limitation, obstructive hypopnea, nonobstructive hypopnea, and snoring events of OSA with an artificial airway and a loudspeaker in a bench model connected to a commercially available auto-PAP device. Four auto-PAP devices were tested, but two of the "older-generation" devices (Tranquility and Virtuoso) did not respond to events of OSA that involved changes in flow contour; hence, we studied the effects of air leak and humidifier in the two "newer-generation" auto-PAP devices only (GoodKnight 418P, Autoset-T). When the air leak was progressively increased from baseline levels recommended by the manufacturer to levels seen clinically--5 to 7, 10, and 30 l/min--the GoodKnight 418P decreased pressure response by 56% (5.6+/-1.8 cm H(2)O, p=0.04). The pressure response of the Autoset-T, however, did not change from baseline during similar levels of air leak. The GoodKnight performed appropriately when the air leak was within 20 l/min, but the corresponding value for the Autoset was higher at 50 l/min. For both devices combined, air leak caused the pressure to drop between the device and the airway: 2.8+/-0.3 cm H(2)O at 30 l/min of air leak (p<0.001). Air leaks cause auto-PAP devices to underestimate the pressure required to treat events of OSA and to overestimate the pressure delivered at the upper airway. Physicians should be aware of performance limitations of auto-PAP devices in the presence of an air leak.

Snoring: analysis, measurement, clinical implications and applications.

Snoring was described in literature even before medicine. Common definitions do not consider acoustic measurements of snoring. In this paper we discuss the main pathophysiological aspects of snoring and the snoring-sleep relationship as the generating mechanisms. Snoring can be analysed and measured by the following methods: 1) Leq-Equivalent Continuous Sound Level, which only quantifies noisiness, annoyance, and damage to the partner's and snorer's hearing; 2) Power Spectrum, with frequency values, formantic structure data and typical shape, which can help to distinguish simple snoring from heavy snoring with obstructive sleep apnoea syndrome (OSAS); 3) Linear Prediction Code (LPC) method, which can define the cross-sectional area (CSA) of the upper airways and which locates sites of obstruction. Simulated snoring analysis with LPC and with simultaneous fluoroscopy permits the definition of CSA and the identification of three snoring patterns: nasal, oral and oronasal. Snoring is an important sign of sleep-related breathing disorders (SRBD), of the upper airway resistance syndrome (UARS), and of the OSAS. Snoring is a symptom of nasal obstruction and is associated with cardiovascular diseases and nocturnal asthma as a trigger or causative factor; however, its acoustic features in these disorders are not well-defined. Home monitoring of snoring is very useful for epidemiology and is mandatory, together with heart rate and arterial oxygen saturation (Sa,O2), to screen SRBD.

Pattern of simulated snoring is different through mouth and nose

Cineradiography of the pharynx during simulated snoring was done in 6 healthy volunteers, and supraglottic pressure and flow rate were recorded in 12 others. We observed, immediately before snoring, a decrease in the sagittal diameter of the oropharynx followed, during snoring, by high-frequency oscillations of soft palate and pharyngeal walls. The pattern of soft palate oscillations was different while snoring through the nose or mouth. During inspiratory snoring through the nose, the soft palate remained in close contact with the back of the tongue and only the uvula presented high-frequency oscillations. Snoring through the mouth resulted in ample high-frequency oscillations of the whole soft palate. Frequency of airflow and supraglottic pressure oscillations was less (P less than 0.05) during mouth (28.2 +/- 7.5 Hz) than during nasal snoring (77.8 +/- 36.7 Hz). This difference may be related to the smaller oscillating mass (i.e., uvula) during nasal snoring. At variance with our previous data, which showed that snoring during sleep, in both heavy (nonapneic) snorers and obstructive sleep apnea patients, was systematically preceded by flow limitation, this was not true during simulated snoring.