Objective Obstructive Sleep Apnea Research Articles

Using entropy of snoring, respiratory effort and electrocardiography signals during sleep for OSA detection and severity classification

Study objectivesObstructive sleep apnea (OSA) is a very prevalent disease and its diagnosis is based on polysomnography (PSG). We investigated whether snoring-sound-, very low frequency electrocardiogram (ECG-VLF)- and thoraco-abdominal effort- PSG signal entropy values could be used as surrogate markers for detection of OSA and OSA severity classification. MethodsThe raw data of the snoring-, ECG- and abdominal and thoracic excursion signal recordings of two consecutive full-night PSGs of 86 consecutive patients (22 female, 53.74 ± 12.4 years) were analyzed retrospectively. Four epochs (30 s each, manually scored according to the American Academy of Sleep Medicine standard) of each sleep stage (N1, N2, N3, REM, awake) were used as the ground truth. Sampling entropy (SampEn) of all the above signals was calculated and group comparisons between the OSA severity groups were performed. In total, (86x4x5 = )1720 epochs/group/night were included in the training set as an input for a support vector machine (SVM) algorithm to classify the OSA severity classes. Analyses were performed for first- and second-night PSG recordings separately. ResultsTwenty-seven patients had mild (RDI = ≥ 5/h but <15/h), 21 patients moderate (RDI ≥15/h but <30/h) and 23 patients severe OSA (RDI ≥30/h). Fifteen patients had an RDI <5/h and were therefore considered non-OSA. Using SE on the above three PSG signal data and using a SVM pipeline, it was possible to distinguish between the four OSA severity classes. The best metric was snoring signal-SE. The area-under-the-curve (AUC) calculations showed reproducible significant results for both nights of PSG. The second night data were even more significant, with non-OSA (R) vs. light OSA (L) 0.61, R vs. moderate (M) 0.68, R vs. heavy OSA (H) 0.84, L vs. M 0.63, M vs. H 0.65 and L vs. H 0.82. The results were not confounded by age or gender. ConclusionsSampEn of either snoring-, very low ECG-frequencies- or thoraco-abdominal effort signals alone may be used as a surrogate marker to diagnose OSA and even predict OSA severity. More specifically, in this exploratory study snoring signal SampEn showed the greatest predictive accuracy for OSA among the three signals. Second night data showed even more accurate results for all three parameters than first-night recordings. Therefore, technologies using only parts of the PSG signal, e.g. sound-recording devices, may be used for OSA screening and OSA severity group classification.

The Cervical Fat Tissue Volume is a Predictor for Moderate to Severe OSA.

Objective Obstructive sleep apnea (OSA) is a disorder characterized by recurrent pharyngeal obstruction during sleep, in which upper airway anatomy plays a key role in its pathogenesis. The aim of this study was to describe whether the quantification of cervical fat tissue volume (CFTV) obtained by Computed Tomography (CT)cephalometry is related to the severity of OSA. Methods Retrospective study between 2018 and 2020 in those patients > 18 years old, with diagnosis of OSA who performed a volumetric cephalometric imaging. Three-dimensional reconstruction of the images was performed and CFTV was measured. Results 91 patients were included in this study of which: without OSA (n: 7), mild (n: 19), moderate (n: 39) and severe OSA (n: 26). We observed a progressive increase of CFTV related to OSA severity has been observed (without OSA: 58.9 ml (47.9-87.5), mild: 59.1ml (48.4-78.3), moderate: 71 ml (42.6-127.1) and severe OSA 103.6 ml (81-153); p < 0.01); nevertheless, no differences were found in the airway volume and neck area. It was showed a significant correlation between CFTV and OSA indicators: AHI, ODI and T90 (Sp r: 0.48; 0.38 and 0.36; p < 0.01 respectively). CFTV cut-off value to discriminate AHI >15 ev/h with best sensitivity-specificity relationship was 64.1 ml with an area under the curve of 0.6 ± 0.06. Multivariate analysis showed that CFTV is a predictor for moderate to severe OSA (OR:3.05, IC95%: 1.14-8.17). Conclusion Cervical fat quantification by CT cephalometry correlates with OSA severity in adults. Fat volume > 64.1 ml increased more than three times the risk of OSA moderate to severe.

STOP-Bang and Smartwatch’s Two-Step Approach for Obstructive Sleep Apnea Screening

Background and Objectives Obstructive sleep apnea (OSA) is associated with various health risks, including hypertension, cerebrovascular disease, myocardial infarction, diabetes, cognitive impairment, and all-cause mortality. While overnight polysomnography (PSG) is the gold standard for diagnosing OSA, it is costly and time-consuming. The STOP-Bang questionnaire is a convenient tool for OSA screening, but its high sensitivity comes at the expense of low specificity. The purpose of this study was to investigate the usefulness of combining the STOP-Bang questionnaire and a smartwatch capable of measuring oxygen saturation in screening for OSA.Subjects and Method Of the patients scheduled for PSG due to OSA, 109 patients voluntarily participated in the study by filling out a STOP-Bang questionnaire during their first visit and wearing a smartwatch during PSG.Results There were 80 males and 29 females, with the patients’ mean age of 45±13.3 years. Based on the apnea-hypopnea index (AHI), 19 patients (17.4%) were normal, 28 (25.7%) had mild OSA, 23 (21.1%) had moderate OSA, and 39 (35.8%) had severe OSA. When using the AHI threshold of AHI ≥15/h, the STOP-Bang alone showed sensitivity of 85.5% and specificity of 61.7%. Combining the STOP-Bang questionnaire with a smartwatch resulted in a slight decrease in sensitivity and a significant increase in specificity, yielding the values of 80.5% and 84.4%, respectively.Conclusion A two-step approach using the STOP-Bang and a smartwatch was implemented to enhance the diagnostic accuracy of screening OSA.

Effect of nocturia in patients with different severity of obstructive sleep apnea on polysomnography: A retrospective observational study

ObjectiveObstructive sleep apnea (OSA) is one of the etiologies of nocturia. We analyzed polysomnography (PSG) results to determine correlated factors related to nocturia in OSA patients with different severity. MethodsPatients with suspected OSA were examined using PSG. They were divided into two groups based on the presence of nocturia. Nocturia was defined as a patient who needed to void at least once. Apnea–hypopnea index (AHI) was employed to classify patients according to degrees of severity: AHI<5 events/h, 5 events/h≤AHI<15 events/h, 15 events/h≤AHI<30 events/h, and AHI≥30 events/h, defined as normal, mild OSA, moderate OSA, and severe OSA, respectively. Demographic variables, PSG parameters, International Prostate Symptom Scores (IPSSs), and quality of life scores due to urinary symptoms were analyzed. ResultsIn total 140 patients, 114 patients had OSA (48 had mild OSA; 34 had moderate OSA; and 32 had severe OSA) and 107 patients had nocturia. The total IPSS was significantly higher in nocturia patients in all groups except the group of severe OSA patients. With the increasing severity of OSA, more correlated factors related to nocturia were determined. In mild OSA patients, nocturia related to increased age (p=0.025), minimum arterial blood oxygenation saturation (p=0.046), and decreased AHI of non-rapid eye movement (p=0.047), AHI of total sleep time (p=0.010), and desaturation index (p=0.012). In moderate OSA patients, nocturia related to increased age (p<0.001), awake time (p=0.025), stage 1 sleep (p=0.033), and sleep latency (p=0.033), and decreased height (p=0.044), weight (p=0.025), and sleep efficiency (p=0.003). In severe OSA patients, nocturia related to increased weight (p=0.011), body mass index (p=0.009), awake time (p=0.008), stage 1 sleep (p=0.040), arousal number (p=0.030), arousal index (p=0.013), periodic limb movement number (p=0.013), and periodic limb movement index (p=0.004), and decreased baseline arterial blood oxygenation saturation (p=0.046). ConclusionOur study revealed that there were more correlated factors related to nocturia with increasing severity of OSA. This study helps in clinical education and treatment for OSA patients with different severity.

Is Obstructive Sleep Apnea a Risk Factor for Severe COVID-19?

Background and Objective Obstructive sleep apnea (OSA) is a breathing disorder during sleep with an obstruction of the upper airway. Previous studies showed OSA as a risk factor for severe COVID-19. It is crucial to determine the risk factors for the severity of COVID-19 infection. We aim to clarify the relationship between COVID-19 severity, and OSA and its degree.Methods Our case-control study included subjects diagnosed with OSA with polysomnography between January 2018 and November 2021, and a control group with a history of COVID-19 infection and without OSA diagnosis. The demographic data, comorbidities, apnea–hypopnea index, and oxygen desaturation index were recorded.Results A total of 217 patients were included in our study. The degree of OSA was a risk factor in the OSA group (p &lt; 0.05); on the other hand, the diagnosis of OSA by itself was not a risk factor. The apnea–hypopnea index and oxygen desaturation index were not related to the severity of COVID-19 infection (p &gt; 0.05). Diabetes mellitus was associated with increased hospitalization in inpatient clinics (p &lt; 0.05) and intensive care unit (ICU) (p &lt; 0.05). Chronic obstructive pulmonary disease was a risk factor for admission to the ICU (p &lt; 0.05).Conclusions Our results showed that moderate-to-severe OSA patients are a vulnerable population to severe COVID-19 infection, although diagnosis of OSA by itself was not a risk factor.

Characteristics of Patients With Severe Obstructive Sleep Apnea Who Maintain Slow-Wave Sleep

Background and Objectives Obstructive sleep apnea (OSA) is a complex sleep-related respiratory disorder with various pathophysiology and clinical manifestations. Diagnosis and treatment considering only the number of respiratory events, such as sleep duration, may have limitations. The purpose of this study is to analyze the clinical and polysomnography (PSG) characteristics of patients with severe OSA in whom slow wave sleep (SWS) was well-maintained.Subjects and Method This study retrospectively analyzed 203 patients who underwent PSG due to suspected OSA. Severe OSA patients were classified into a SWS maintained group (SWS≥15%) and a SWS reduced group (SWS&lt;15%), and their clinical records, PSG results, and heart rate variability (HRV) were compared.Results The SWS maintained group (n=27), compared to the SWS reduced group (n=58), had a significantly longer total sleep time (&lt;i&gt;p&lt;/i&gt;=0.027) and lower wake after sleep onset (&lt;i&gt;p&lt;/i&gt;=0.001), rapid eye movoement (REM) latency (&lt;i&gt;p&lt;/i&gt;=0.007), non-supine apnea-hypopnea index (AHI, &lt;i&gt;p&lt;/i&gt;=0.006), non-REM AHI (&lt;i&gt;p&lt;/i&gt;&lt;0.001), arousal index (&lt;i&gt;p&lt;/i&gt;&lt;0.001) and Epworth Sleepiness Scale (&lt;i&gt;p&lt;/i&gt;=0.048). In addition, the SWS maintained group had a significantly low value in very low frequency in HRV than that of the SWS reduced group (&lt;i&gt;p&lt;/i&gt;=0.046).Conclusion The SWS maintained group in the severe OSA showed better PSG and HRV results and reduced daytime sleepiness than those of the SWS reduced group.

Alterations of brain gray matter volume in children with obstructive sleep apnea.

Obstructive sleep apnea (OSA) seriously affects the children's cognitive functions, but the neuroimaging mechanism of cognitive impairment is still unclear. The purpose of our study was to explore the difference in brain local gray matter volume (GMV) between children with OSA and non-OSA, and the correlation between the difference regions of brain gray matter volume and cognitive, the severity of OSA. Eighty-three children aged 8-13 years were recruited in our study, 52 children were diagnosed as OSA by polysomnography, and 31 as the non-OSA. All the subjects were underwent high-resolution 3-dimensional T1-weighted magnetic resonance images. The voxel-based morphometry (VBM) was be used to analyse the local GMV. The Das-Naglieri cognitive assessment system (DN: CAS) was used to assess the subjects' cognitive. The difference of local GMV between the two groups was analyzed by two-sample T-test. The PSG variables and the scores of DN: CAS between the OSA group and non-OSA group were compared by independent samples t-tests. Pearson correlation was used to calculate the association between the difference areas of gray matter volumes in brain and DN: CAS scores, obstructive apnea/hypopnea index (OAHI, an index of the severity of OSA). The gray matter volume of the right Middle Frontal Gyrus (MFG_R) in OSA children were larger than the non-OSA children, and the OSA children had lower scores of the Word Series in DN: CAS. There was negative correlation between the scores of Expressive Attention in DN: CAS and the gray matter volume of the right middle frontal gyrus, and it was no significantly correlation between OAHI and the gray matter volume of the right middle frontal gyrus. Our results suggest that the development of gray matter volume in frontal cortex, which associated with attention, were sensitive to the effects of OSA, provides neuroimaging evidence for cognitive impairment in children with OSA.

Effects of Continuous Positive Airway Pressure on White Matter Microstructure in Patients With Obstructive Sleep Apnea

Background and Objective Obstructive sleep apnea (OSA) has significant effects on quality of life and may lead to cognitive impairments. Continuous positive airway pressure (CPAP) is the standard treatment for OSA and has been shown to improve sleep disturbances and daytime dysfunction. In this study, we aimed to assess the effects of CPAP on white matter (WM) integrity using longitudinal diffusion tensor imaging (DTI) tests.Methods Twenty-two male patients with moderate to severe OSA were recruited, and thepatients underwent DTI scanning before and 6–44 months after CPAP treatment. Sixteen male patients with untreated OSA who were not compliant with CPAP were included as a reference group. We compared the functional anisotropy (FA) values between baseline and follow-up magnetic resonance imaging in both the CPAP and untreated groups using tract-specific statistical analysis (TSSA) method.Results The TSSA analysis showed that FA values in the middle part of the right corticospinal tract were increased after treatment in the CPAP group. In the untreated group, no significant change in FA value was observed between baseline and follow-up. In the CPAP group, the post-treatment FA value in the anterior part of the right anterior thalamic radiation was significantly correlated with the duration of CPAP therapy, after controlling for age, body mass index, and baseline FA value.Conclusions Our study suggests that long-term CPAP treatment could gradually reverse OSA-induced injury to the WM microstructure, particularly WM associated with the motor and limbic systems. The study findings provide new insights into the mechanisms of cognitive improvement after CPAP treatment in patients with OSA.

Estimates of 10-year risk of cardiovascular death and adherence to cardiovascular risk factor management in Danish patients investigated for obstructive sleep apnea

ObjectiveObstructive sleep apnea (OSA) increases the risk of cardiovascular disease (CVD) in both morbidity and mortality. We used the risk chart of Systemic Coronary Risk Evaluation (SCORE) from European Society of Cardiology (ESC) to determine the 10-year risk of cardiovascular death, and adherence to cardiovascular risk factor management in Danish patients investigated for obstructive sleep apnea. Research design and methodsIn a prospective cohort study, 303 patients with mild, moderate and severe OSA were investigated for cardiovascular risk factors before initiating CPAP therapy. Primary outcome was estimates of 10-year risk of cardiovascular death assessed from the ESC risk chart SCORE based on sex, age, smoking status, systolic blood pressure and s-total cholesterol. Furthermore we analyzed treatment indication with statins in patients with mild (apnea-hypopnea index, AHI <15), moderate (AHI 15–29.9) and severe OSA (AHI ≥30). ResultsPatients with mild OSA predominately had low or moderate 10-year risk of CVD (low risk 55.4%, moderate risk 30.8%) while patients with moderate and severe OSA were more likely to have high or very high risk of 10-year CVD (p = 0.001). The large majority of included OSA patients had dyslipidemia, 235 (77.6%) and of those, only 27.4% were treated with cholesterol lowering drugs while additional 27.7% were eligible for oral statin supplement as risk-estimated by the ESC SCORE. In multiple regression analysis among statin naive patients, AHI was positively associated with statin eligibility when adjusted for age and sex. ConclusionPatients with moderate and severe OSA had an elevated 10-year risk of fatal CVD and were undertreated with CVD risk lowering agents such as statins.

Relationship of obstructive sleep apnea with periodontal condition and its local and systemic risk factors

ObjectiveObstructive sleep apnea (OSA) and periodontitis share risk factors, such as age, obesity, stress, and cardiovascular events, which have a bidirectional cause-effect relationship through systemic inflammation. Our objective was to determine the relationship between OSA and the periodontal condition and its associated local and systemic risk factors.Material and methodsThis was an observational case-control study involving 60 patients. Local oral risk factors and the systemic condition of each patient were evaluated. All patients underwent polysomnography for the diagnosis of OSA. Chi-squared, one-way ANOVA, and Bonferroni’s tests were performed.ResultsA higher percentage of patients with periodontitis had severe OSA (66.66%); however, no statistically significant association was found between the two pathologies (p = 0.290). In terms of systemic risk factors, an association was found between arterial hypertension and severe OSA (p = 0.038), and in terms of local factors, an association was found between the use of removable prostheses and severe OSA (p = 0.0273).ConclusionIn the general population, patients with periodontitis showed a higher prevalence of severe OSA. Obesity and hypothyroidism were the most prevalent systemic findings in patients with OSA and periodontitis. Arterial hypertension and osteoarthritis were found to be associated with severe OSA. The local risk factors associated with periodontitis and severe OSA were removable partial dentures and misfit resins.Clinical relevanceTo study the factors that can facilitate the progression of OSA and periodontitis, physicians and dentists should be advised to provide comprehensive care for patients with both pathologies.

The protective role of Nrf2 on cognitive impairment in chronic intermittent hypoxia and sleep fragmentation mice

ObjectiveObstructive Sleep Apnea Hypopnea Syndrome (OSAHS) is a sleep respiratory disease associated with cognitive impairment, The nuclear factor erythroid 2 related factor 2 (Nrf2) plays a neuroprotective role. This study was designed to investigate the mechanism of Nrf2 protecting neural cells from endoplasmic reticulum stress (ERS), induced by chronic intermittent hypoxia (CIH) and sleep fragmentation (SF) which caused cognitive impairment in mice. MethodsEstablishment of CIH and SF mice to simulate OSAHS mouse model. An eight-arm maze behavior test measured the cognitive function of mice, and Nissl staining and TUNEL staining were used to detect pathological changes in hippocampal neurons. The expression of ERS and Nrf2 and its downstream related mRNAs and proteins were detected by qRT-PCR and Western blotting. ResultsCIH and SF lead to cognitive impairment in mice, and Sulforaphane (SFN, Nrf2 agonist) plays a protective role, while Nrf2-KO aggravates the cognitive impairment. CIH and SF reduced the number of Nissl bodies in neurons and induced apoptosis. The mRNA levels of BiP, CHOP, Nrf2, GCLC and Prdx1 in CIH, SF and CIH + SF groups were increased (p = 0.001), whereas the mRNA levels of BiP and CHOP in the CIH + SF + SFN group were decreased (p = 0.02) while those of Nrf2 and Prdx1 were increased (p = 0.005). The CIH + SF + Nrf2-KO group, the mRNA levels of CHOP were increased (p = 0.001) while Nrf2, GCLC and Prdx1 were decreased (p = 0.001). The protein levels of CHOP and active Caspase-12 in CIH, SF, CIH + SF and CIH + SF + Nrf2-KO groups were increased (p = 0.03), while those of Prdx1 and Nrf2 were increased (p = 0.03) in the CIH + SF + SFN group, while decreased (p = 0.02) in the Nrf2-KO group. ConclusionsChronic intermittent hypoxia(CIH) and sleep fragmentation(SF) could aggravate the inflammatory response of nerve cells through endoplasmic reticulum stress, leading to apoptosis of nerve cells, and causing cognitive impairment in mice.Nrf2 alleviates cognitive impairment induced by chronic intermittent hypoxia and sleep fragmentation by modulating endoplasmic reticulum stress. Activation of Nrf2 protects cognitive impairment through the Nrf2-Prdx1 signaling pathway.

Nocturnal hypoxia indexes are associated with left ventricular remodeling and diastolic dysfunction in obstructive sleep apnea patients

Background and objectiveObstructive sleep apnea (OSA) is associated with heart derangements detected at echocardiography as higher left ventricular mass index (LVMI), higher left ventricular end-diastolic diameter, lower left ventricular ejection fraction (LVEF), and impaired diastolic function. However, the currently used parameter to define OSA diagnosis and severity, the apnea/hypopnea index (AHI), poorly predicts cardiovascular damage, cardiovascular events, and mortality. Our study aimed to assess if other polygraphic indices of OSA presence and severity, in addition to AHI, might better predict echocardiographic cardiac remodeling. Methods and resultsWe enrolled two cohorts of individuals referred for suspected OSA to the outpatient facilities of the IRCCS Istituto Auxologico Italiano, Milano, and of the Clinica Medica 3, Padova. All patients underwent home sleep apnea testing and echocardiography. Based on the AHI the cohort was divided into no-OSA (AHI<15 events/hour) and moderate-severe OSA (AHI≥15 events/hour). We recruited 162 patients and found that compared to patients with no-OSA, those with moderate-severe OSA showed higher LV remodeling [left ventricular end-diastolic volume (LVEDV) 48.4 ± 11.5 ml/m2 vs. 54.1 ± 14.0 ml/m2, respectively, p = 0.005] and lower LVEF (65.3 ± 5.8% vs. 61.6 ± 7.8%, respectively, p = 0.002), whereas we could not find any difference in LVMI and early and late ventricular filling velocity ratio (E/A). At multivariate linear regression analysis two polygraphic hypoxic burden-related markers were independent predictors of LVEDV and E/A, i.e., the percentage of time with O2 saturation below 90% (β = 0.222) and ODI (β = −0.422), respectively. ConclusionsOur study shows that nocturnal hypoxia-related indexes were associated with left ventricular remodeling and diastolic dysfunction in OSA patients.

Screening the risk of obstructive sleep apnea by utilizing supervised learning techniques based on anthropometric features and snoring events.

Obstructive sleep apnea (OSA) is typically diagnosed by polysomnography (PSG). However, PSG is time-consuming and has some clinical limitations. This study thus aimed to establish machine learning models to screen for the risk of having moderate-to-severe and severe OSA based on easily acquired features. We collected PSG data on 3529 patients from Taiwan and further derived the number of snoring events. Their baseline characteristics and anthropometric measures were obtained, and correlations among the collected variables were investigated. Next, six common supervised machine learning techniques were utilized, including random forest (RF), extreme gradient boosting (XGBoost), k-nearest neighbor (kNN), support vector machine (SVM), logistic regression (LR), and naïve Bayes (NB). First, data were independently separated into a training and validation dataset (80%) and a test dataset (20%). The approach with the highest accuracy in the training and validation phase was employed to classify the test dataset. Next, feature importance was investigated by calculating the Shapley value of every factor, which represented the impact on OSA risk screening. The RF produced the highest accuracy (of >70%) in the training and validation phase in screening for both OSA severities. Hence, we employed the RF to classify the test dataset, and results showed a 79.32% accuracy for moderate-to-severe OSA and 74.37% accuracy for severe OSA. Snoring events and the visceral fat level were the most and second most essential features of screening for OSA risk. The established model can be considered for screening for the risk of having moderate-to-severe or severe OSA.

Causal associations of obstructive sleep apnea with cardiovascular disease: a Mendelian randomization study.

Obstructive sleep apnea (OSA) had been associated with various cardiovascular diseases (CVDs) in observational studies, but causal inferences have not been confirmed. We used the Mendelian randomization (MR) study to explore the potential causal association between OSA with CVDs in the general population. We performed a two-sample MR analysis using five gene-wide significant single-nucleotide polymorphisms associated with OSA at genome-wide significance from the FinnGen study (N = 217 955) and 12 cardiovascular diseases from the UK Biobank and the genetic consortia. The inverse-variance weight was chosen as the primary analysis and was complemented by various sensitivity analyses. The study design applied univariable MR, multivariable MR, and mediation analysis. MR analyses provide evidence of genetically predicted OSA on the risk of heart failure (odds ratio [OR],1.26; 95% confidence interval [CI],1.08 to 1.47), hypertension (OR,1.24; 95%CI, 1.11 to 1.39) and atrial fibrillation (OR,1.21; 95%CI,1.12 to 1.31). Multivariable MR indicated the adverse effect of OSA on heart failure persisted after adjusting BMI, smoking, drinking, and education (IVW OR,1.13; 95%CI, 1.01 to 1.27). However, the significance of hypertension and atrial fibrillation was dampened. Mediation analyses suggest that the causal association between OSA and heart failure is mediated in part by Apolipoprotein B, with a mediated portion of 9%. This study suggested that genetically predicted OSA is a potential causal risk factor for heart failure based on a large-scale population. Nevertheless, further studies regarding ancestral diversity are needed to confirm the causal association between OSA and CVDs.

Altered intrinsic brain functional network dynamics in moderate-to-severe obstructive sleep apnea

ObjectivesObstructive sleep apnea (OSA) can affect temporal fluctuations in brain activity during rest. Dynamic functional connectivity (dFC) captures the fluctuations in FC during the resting state. This study aimed to investigate differences in dFC between moderate-to-severe OSA patients and healthy controls using resting-state functional magnetic resonance imaging (fMRI) and sliding-window analysis. MethodsThirty-seven consecutive patients with moderate-to-severe OSA and 16 age- and sex-matched controls underwent resting-state fMRI in the morning following overnight polysomnography. The dynamics of aberrant FC between the groups and the correlation between the dynamics and clinical variables were evaluated. ResultsdFC analysis revealed two distinct connectivity states: hypoconnected (State I) and hyperconnected (State II). In OSA patients, State I occurred 34% more often than in the controls and the occurrence of State II was proportionally reduced. The time in State I positively correlated with the Pittsburg Sleep Quality Index score in the OSA patients. ConclusionsThis study showed dFC alterations in moderate-to-severe OSA patients, which may serve as a novel physiological biomarker for OSA.

Homecare interventions as a Service model for Obstructive sleep Apnea: Delivering personalised phone call using patient profiling and adherence predictions

Background and ObjectiveObstructive Sleep Apnea (OSA) is a sleep disorder that leads to different pathologies like depression and cardiovascular problems. The first-line medical treatment for OSA is Continuous Positive Airway Pressure (CPAP) therapy. However, this therapy has the lowest adherence level when compared to other homecare therapies. Consequently, the main objective of this paper is to increase this adherence level with methods that can be replicated in a large number of patients. MethodsThe Homecare Intervention as a Service model can build, verify, and deliver per-sonalised home care interventions. With the Homecare Intervention as a Service model, we build and provide on-demand personalised interventions according to the patient’s needs. The 2 core components of this model are patient clustering and CPAP adherence predictions. To define the patient profiles and predict the adherence level, we apply the K-means and the Logistic Regression algorithm respectively. To support these algorithms, we use the CPAP monitoring data and qualitative data on the patients. ResultsWe demonstrate that there are 3 patient profiles (non-adherent, attempter, and adherent). We draw a comparison with multiple machine learning algorithms to predict CPAP adherence at 30, 60 and 90 days. In this case, the Logistic Regression gives the best results with a f1-score of 0.84 for30 days, 0.79 for 60 days and 0.76 for 90 days. These newly build profiles were to be used to deliver personalised phone call interventions. The phone call intervention shows an increase in adherence by 1.02 h/night for non-adherent patients and 0.69 h/night for attempter patients. ConclusionsThis is the first study in CPAP therapy that formalises the process of transforming raw data into effective home care interventions that can be delivered directly to the patients. In fact,it is the first time that both patient characterisation and predictions based on data are used to provide personalised patient management for CPAP therapy. Our model is flexible to be extended to new types of interventions and other homecare therapies.

P040 Obstructive sleep apnea during REM sleep: Effects on morning and evening blood pressure

Abstract Study Objectives Obstructive sleep apnea (OSA) is linked to the emergence and progression of cardiovascular complications including hypertension, stroke, arrhythmias, coronary artery disease and heart failure. Epidemiological studies have reported that hypertension is associated with respiratory events during REM sleep. We examined the relationship between respiratory events during REM and morning and evening hypertension in a clinical sleep population. Methods This study included data from in-laboratory diagnostic polysomnographic studies (n=797) from adults attending for investigation of OSA. Hypertension was defined using blood pressure measurements taken in the evening before and morning after polysomnography, and use of anti-hypertensive medication. Regression modelling was undertaken to examine the probability of evening and morning hypertension according to REM apnea hypopnea index (AHI), NREM AHI, gender, age, body mass index (BMI), alcohol use, total sleep time (TST), sleep time SpO2 &amp;lt;90%, smoking and waist-to-hip ratio. Results The probability of morning hypertension was significantly independently associated with age (p&amp;lt;0.001), BMI (p&amp;lt;0.001) and REM AHI (p=0.012). No significant effect was found for male gender, NREM AHI, alcohol use, TST, sleep time SpO2 &amp;lt;90%, smoking or waist-to-hip ratio (p&amp;gt;0.05 for all). The probability of evening hypertension was only significantly associated with age (p&amp;lt;0.001), BMI (p&amp;lt;0.001) and TST (p=0.029). Conclusions Respiratory events during REM sleep are significantly associated with morning hypertension. Future research is needed to determine whether treatment of these events can prevent or reverse morning hypertension.

Pharyngoplasty for obstructive sleep apnea: The influence of surgical technique

Introduction and objectivesObstructive sleep apnea is the most frequent sleep disorder worldwide, with rising incidence. Pharyngoplasty is an alternative treatment in patients not suitable to continuous positive airway pressure devices (CPAP). The aim of this study is to compare different surgical techniques of pharyngoplasty for treatment of obstructive sleep apnea and evaluate its influence in surgical success. Material and methodsRetrospective study of 92 patients that underwent pharyngoplasty for treatment of obstructive sleep apnea from 2001 to 2020. Included patients performed classic uvulopalatopharyngoplasty (UPPP), radiofrequency assisted uvulopalatopharyngoplasty (RF-UPPP) or barbed reposition pharyngoplasty (BRP). Surgical success was defined and outcomes and complications assessed for each procedure. ResultsMost patients were male, with a mean age of 49.36±9.6 years and a mean apnea hypopnea index (AHI) of 29.14±2.94events/h. Thirty-six patients performed classic UPPP, thirty-one underwent RF-UPPP and the remaining twenty-five performed BRP. BRP achieved the highest success rate (66%) in comparison with UPPP (57%) and RF-UPPP (54%) (p=0.032). Mean relative AHI reduction after surgery was not statistically different between three procedures (p=0.098), although there was a tendency for greater reduction with BRP. Most symptoms improved after surgery and snoring was the most recurrent symptom. BRP had less foreign body sensation after surgery, however, it was the procedure with highest rate of post-operative tonsillar bleeding. ConclusionsIn our department, the introduction of recent techniques of velopharyngeal surgery, focused in functional and lateral muscular collapse, has translated into an increase in success rate after surgery. The relative ease of the procedure and reduction of long term complications make BRP an attractive alternative option for CPAP in OSA, in carefully selected patients.

Obstructive sleep apnea during REM sleep: effects on morning and evening blood pressure.

Obstructive sleep apnea (OSA) is linked to the emergence and progression of cardiovascular complications including hypertension, stroke, arrhythmias, coronary artery disease, and heart failure. Epidemiological studies have reported that hypertension is associated with respiratory events during REM sleep. We examined the relationship between respiratory events during REM and morning and evening hypertensive blood pressure (BP) levels in a clinical sleep population. This study included data from in-laboratory diagnostic polysomnographic studies (n = 797) from adults attending for investigation of OSA. Hypertensive BP levels were defined using BP measurements taken in the evening before and morning after polysomnography, and the use of antihypertensive medication. Regression modeling was undertaken to examine the probability of evening and morning hypertensive BP levels according to REM apnea-hypopnea index (AHI), NREM AHI, gender, age, body mass index (BMI), alcohol use, total sleep time (TST), sleep time SpO2 <90%, and smoking status. The probability of morning hypertensive BP levels was significantly independently associated with age (p < .001), BMI (p < .001), and REM AHI (p < .001). No significant effect was found for the male gender, NREM AHI, alcohol use, TST, sleep time SpO2 <90%, or smoking (p > .05 for all). The probability of evening hypertensive BP levels was only significantly associated with age (p < .001), male gender (p = .012), BMI (p < .001), and TST (p = .032). Respiratory events during REM sleep are significantly associated with morning hypertensive BP levels. Future research is needed to determine whether treatment of these events can prevent or reverse morning hypertensive BP levels.

Parameters affecting improvement of excessive daytime sleepiness in obstructive sleep apnea patients

ObjectivesObstructive sleep apnea (OSA) is a sleep-related breathing disorder caused by repetitive obstruction of the upper airway; this impairs gaseous exchange, resulting in hypoxia, hypercapnia, and frequent arousals. Excessive daytime sleepiness (EDS) is a common daytime symptom of OSA. EDS manifests as fatigue and impaired attention, leading to poor performance at work and falling asleep while driving, which is a major socioeconomic problem. Therefore, it is important to properly treat EDS and accurately predict the response to treatment. However, few studies have compared OSA patients showing and not showing improvement in EDS. Therefore, this study aimed to objectively analyze and compare EDS improvement and non-improvement groups. Subjects and methodsWe retrospectively reviewed the medical records of 57 OSA patients with EDS. Patients were divided into two groups according to the improvement in EDS after positive airway pressure (PAP) device treatment. We analyzed differences in clinical records including patients' age, sex, history of smoking, hypertension, diabetes, myocardial infarction, and cerebrovascular disease between the two groups. Systolic, diastolic blood pressure, blood test including blood glucose, total cholesterol, high- and low-density lipoprotein cholesterol, and triglyceride levels were also analyzed. Polysomnography (PSG) data, PAP device treatment compliance and scores of questionnaires related to various psychiatric symptoms, subjective sleep quality between the two groups were also analyzed. ResultsThere was no statistically significant difference in age, gender, or past medical history between the two groups. Systolic and diastolic blood pressure, and blood test results, were also not significantly different. Among the questionnaires related to various psychiatric symptoms, the groups showed statistically significant differences in Social Avoidance and Distress Scale (SADS) and Fear of Negative Evaluation (FNE) scores (P = 0.001 and 0.020, respectively). The group differences in the scores on the other questionnaires were not significantly different. Among the PSG items, significant group differences were observed in the percentage of stage 2 non-REM sleep (N2%, P = 0.023), apnea index (AI, P = 0.005), apnea-hypopnea index (AHI, P = 0.023), and frequency of 3 % oxygen desaturation (ODI3, P = 0.001). No obesity-related parameters showed significant group differences. The percentage of days on which a PAP device was used (out of 90 days; PAP%) and percentage of days on which a PAP device was used for >4 h (Time4%) did not differ significantly. ConclusionsThe SADS, FNE, AI, AHI, N2%, and ODI3 parameters differed significantly between the EDS improvement and non-improvement groups. These parameters may help clinicians treat and predict the prognosis of patients suffering with EDS.