Prevalence and characteristics of positional sleep apnea in the HypnoLaus population-based cohort

Analysing the impact of body position shift on sleep architecture and stage transition: A comprehensive multidimensional study using event-synchronised polysomnography data

Although understanding the physiological mechanisms of obstructive sleep apnea (OSA) is important for treating OSA, limited studies have examined OSA patients' sleep architecture at the epoch-by-epoch level and analysed the impact of sleep position and stage on OSA pathogenesis. The epoch-labelled polysomnogram was analysed multidimensionally to investigate the effect of sleep position on the sleep architecture and risk factors of apnea in patients with OSA. This retrospective multicentric case-control study reviewed full-night diagnostic polysomnography of 6983 participants. The difference in the proportion of time spent supine during non-rapid eye movement (NREM) and REM stages, and the mean duration of respiratory events per body position were evaluated. The frequency of sleep stage transition per body position shift type was computed. Further subgroup analysis was performed based on OSA severity and positional dependency. Supine time in patients with OSA varied across sleep stages, with lower proportions in N3 and REM, and shorter durations with severity. Patients with OSA spent less time in supine positions during N3 and REM, and experienced longer apnea events in both positions compared to the control group. The frequency of all sleep stage transitions increased with OSA severity and was higher among non-positional OSA than positional OSA and the control group, regardless of body position shift type. The sleep stage transition from N3 and REM to wakefulness was notably heightened during position shift. Understanding the sleep architecture of patients with OSA requires analysing various sleep characteristics including sleep position simultaneously, with future studies focusing on position detection to predict sleep stages and respiratory events.

Comparison of sleep position monitoring between NaTu sensor and video-validated polysomnography in patients with obstructive sleep apnea

PURPOSE

This study aimed to evaluate the accuracy of a Bluetooth position monitor called NaTu sensor and its mobile phone application for detecting sleep position among patients with obstructive sleep apnea (OSA) during polysomnography (PSG).

METHODS

A cross-sectional study was conducted on adults with suspected of having OSA who underwent PSG. Sleep positions were recorded simultaneously using a video-validated PSG position sensor and the NaTu sensor. The area under the Receiver Operator Characteristic curve (ROC AUC), sensitivity, and specificity values were calculated to evaluate the validity of the NaTu sensor.

RESULTS

Ninety participants (56.7% male) were included, with median age of 40.0 years and body mass index of 29.4 kg/m2. The mean AHI was 58.4 ± 31.2 events/hour, categorizing the severity of OSA as mild (5.6%), moderate (18.9%), and severe (75.5%). Sleep positions (supine, lateral right, lateral left) identified by the NaTu sensor closely agreed with the video-validated PSG. The kappa statistic demonstrated almost perfect agreement (k = 0.95, P < 0.001) for overall position recording. The ROC AUC for identifying supine, lateral right, and lateral left positions ranged from 0.974 to 0.981, with sensitivity ranging from 95.1% to 99.1% and specificity from 96.5% to 99.6%.

CONCLUSION

Our wearable sensor monitoring significantly agrees with video-validated PSG in identifying sleep positions. This device is reliable and accurate for position monitoring and could be an alternative tool for monitoring positions in in-lab PSG, home sleep apnea testing, or tracking positional treatment at home.

REGISTRATION

Thaiclinicaltrials.org with number TCTR20210701008.

Positional Treatment of Obstructive Sleep Apnea

Positional sleep apnea (POSA), a distinctive subtype of obstructive sleep apnea, underscores the critical influence of a patient's sleeping position on the severity of their condition. In the management of POSA, compliance with positional therapy (PT) is paramount, as it wields a profound impact on the treatment's efficacy and the overall alleviation of the disease. The advent of new-generation PT devices offers a promising alternative to conventional methods like the tennis ball technique, boasting higher compliance rates and substantial disease alleviation.

In-Laboratory Polysomnography Worsens Obstructive Sleep Apnea by Changing Body Position Compared to Home Testing

(1) Background: Home sleep apnea testing, known as polysomnography type 3 (PSG3), underestimates respiratory events in comparison with in-laboratory polysomnography type 1 (PSG1). Without head electrodes for scoring sleep and arousal, in a home environment, patients feel unfettered and move their bodies more naturally. Adopting a natural position may decrease obstructive sleep apnea (OSA) severity in PSG3, independently of missing hypopneas associated with arousals. (2) Methods: Patients with suspected OSA performed PSG1 and PSG3 in a randomized sequence. We performed an additional analysis, called reduced polysomnography, in which we blindly reassessed all PSG1 tests to remove electroencephalographic electrodes, electrooculogram, and surface electromyography data to estimate the impact of not scoring sleep and arousal-based hypopneas on the test results. A difference of 15 or more in the apnea-hypopnea index (AHI) between tests was deemed clinically relevant. We compared the group of patients with and without clinically relevant differences between lab and home tests (3) Results: As expected, by not scoring sleep, there was a decrease in OSA severity in the lab test, similar to the home test results. The group of patients with clinically relevant differences between lab and home tests presented more severe OSA in the lab compared to the other group (mean AHI, 42.5 vs. 20.2 events/h, p = 0.002), and this difference disappeared in the home test. There was no difference between groups in the shift of OSA severity by abolishing sleep scoring in the lab. However, by comparing lab and home tests, there were greater variations in supine AHI and time spent in the supine position in the group with a clinically relevant difference, either with or without scoring sleep, showing an impact of the site of the test on body position during sleep. These variations presented as a marked increase or decrease in supine outcomes according to the site of the test, with no particular trend. (4) Conclusions: In-lab polysomnography may artificially increase OSA severity in a subset of patients by inducing marked changes in body position compared to home tests. The location of the sleep test seems to interfere with the evaluation of patients with more severe OSA.

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.

A review of supine position related obstructive sleep apnea: Classification, epidemiology, pathogenesis and treatment

Supine related obstructive sleep apnea (OSA) is the most common clinical and physiological phenotype of OSA. This condition is recognizable by patients, their families and through polysomnographic recordings. Commonly used definitions distinguish the presence of supine related OSA when respiratory events occur at twice the frequency when the patient lies in the supine compared to non-supine sleeping positions. Recent physiology studies have demonstrated that airway obstruction arises more commonly in the supine position particularly at the level of the soft palate and epiglottis. Increased airway collapsibility is reliability observed supine relative to lateral position. To a lesser extent, changes in control of breathing favour less stable ventilation when the supine sleeping posture is adopted. Many treatments have been developed and trialled to help patients avoid sleeping on their back. The last 10 years has seen the emergence of vibrotactile warning devices that are worn on the patients' neck or chest. High quality randomized controlled trial data is accumulating on the efficacy and common pitfalls of the application of these treatments.

Mechanisms relating to sleeping position to the endotypes of sleep disordered breathing

PURPOSE

Obstructive sleep apnea (OSA) severity varies considerably depending on the body position during sleep in certain subjects. Such variability may be underpinned by specific, body position-related changes in OSA pathophysiological determinants, or endotypes. Also head position relative to trunk may influence OSA endotypes. However, no studies to our knowledge have reviewed the endotype variations according to head or body position up to now.

RECENT FINDINGS

Several findings illustrate that supine OSA is mostly attributable to unfavorable upper airway anatomy compared to lateral position. However, a reduced lung volume, with consequent ventilatory instability (or elevated loop gain), may also play a role. Furthermore, preliminary findings suggest that prone and reclined positions may have a beneficial effect on collapsibility and loop gain.

SUMMARY

Sleeping supine induces many unfavorable pathophysiological changes, especially in certain predisposed OSA patients. Little is known on the influence of other sleep positions on key endotypic traits.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Prediction of Sleep Apnea Events Using a CNN-Transformer Network and Contactless Breathing Vibration Signals

It is estimated that globally 425 million subjects have moderate to severe obstructive sleep apnea (OSA). The accurate prediction of sleep apnea events can offer insight into the development of treatment therapies. However, research related to this prediction is currently limited. We developed a covert framework for the prediction of sleep apnea events based on low-frequency breathing-induced vibrations obtained from piezoelectric sensors. A CNN-transformer network was utilized to efficiently extract local and global features from respiratory vibration signals for accurate prediction. Our study involved overnight recordings of 105 subjects. In five-fold cross-validation, we achieved an accuracy of 85.9% and an F1 score of 85.8%, which are 3.5% and 5.3% higher than the best-performed classical model, respectively. Additionally, in leave-one-out cross-validation, 2.3% and 3.8% improvements are observed, respectively. Our proposed CNN-transformer model is effective in the prediction of sleep apnea events. Our framework can thus provide a new perspective for improving OSA treatment modes and clinical management.

The Prevalence of Positional Obstructive Sleep Apnoea in a Sample of the Saudi Population

PURPOSE

Positional obstructive sleep apnoea (POSA) is of important clinical significance, as positional treatment can augment or obviate continuous positive airway pressure. This study aimed to determine the prevalence of POSA and its characteristics using different definitions.

METHODS

We retrospectively examined a cohort of patients who underwent polysomnography (PSG) between 2013 and 2019 at two sleep centres. Demographic data and PSG data were collected from 624 patients with an apnoea-hypopnea index (AHI) ≥ 5. POSA was defined using different criteria as follows: (1) AHI of at least twice as high in the supine position as in the lateral position (Cartwright' s definition). (2) A supine AHI ≥ 10 and a lateral AHI < 10 (Marklun's definition). (3) AHI of at least twice as high in the supine position than in the lateral position, with the lateral AHI not exceeding 5 (Mador's definition or Exclusive POSA; e-POSA). (4) AHI ≥ 15/h; a supine AHI ≥ twice that of the nonsupine AHI ≥ 20 min of sleep in the supine and nonsupine positions; and a nonsupine AHI < 15 (Bignold's definition).

RESULTS

The prevalence of POSA was 54% (Cartwright), 38.6% (Mador), 33.8% (Marklund) and 8.3% (Bignold). Multivariate regression analysis showed a body mass index (BMI) < 35 kg/m² was the only significant predictor of POSA. Mador's definition had the highest diagnostic yield (sensitivity 63%; specificity 100%; area under the receiver operating characteristic curve 90.2%).

CONCLUSION

POSA is common, but its prevalence depends on the definition used. Low BMI was identified as a significant predictor.

Characteristics of patients with positional OSA according to ethnicity and the identification of a novel phenotype-lateral positional patients: a Multi-Ethnic Study of Atherosclerosis (MESA) study

STUDY OBJECTIVES

We investigated the characteristics of obstructive sleep apnea (OSA) positional patients' (PP) phenotypes among different ethnic groups in the Multi-Ethnic Study of Atherosclerosis (MESA) dataset. Moreover, we hypothesized the existence of a new OSA PP phenotype we coined "Lateral PP," for whom the lateral apnea-hypopnea index is at least double the supine apnea-hypopnea index.

METHODS

From 2,273 adults with sleep information, we analyzed data of 1,323 participants who slept more than 4 hours and had at least 30 minutes of sleep in both the supine and the nonsupine positions. Demographics and clinical information were compared for the different PP and ethnic groups.

RESULTS

861 (65.1%) patients had OSA, and 35 (4.1%) were Lateral PP. Lateral PP patients were mainly females (62.9%), obese (median body mass index: 31.4 kg/m2), had mild-moderate OSA (94.3%), and mostly were non-Chinese American (97.1%). Among all patients with OSA, 550 (63.9%) were Supine PP and 17.7% were supine-isolated OSA. Supine PP and Lateral PP were present in 73.1% and 1.0% of Chinese Americans, 61.0% and 3.4% of Hispanics, 68.3% and 4.7% of White/Caucasian, and 56.2% and 5.2% of Black/African-American patients with OSA.

CONCLUSIONS

Chinese Americans have the highest prevalence of Supine PP, whereas Black/African-American patients lean toward less Supine PP and higher Lateral PP. Lateral PP appears to be a novel OSA phenotype. However, Lateral PP was observed in a small group of patients with OSA and thus its existence should be further validated.

CITATION

Ben Sason Y, Oksenberg A, Sobel JA, Behar JA. Characteristics of patients with positional OSA according to ethnicity and the identification of a novel phenotype-lateral positional patients: a Multi-Ethnic Study of Atherosclerosis (MESA) study. J Clin Sleep Med. 2023;19(3):529-538.

Evaluating symptoms and polysomnographic findings among male and female children with obesity with and without obstructive sleep apnea

OBJECTIVE

Limited data regarding sex-based differences in the presentation and phenotype of obstructive sleep apnea (OSA) exists among children with obesity. The study objectives were to compare reported symptoms and polysomnogram (PSG) findings between children with obesity 1) with and without OSA and 2) males and females with OSA.

PATIENTS/METHODS

This cross-sectional study included children with obesity, aged 8-18 years, with a diagnostic PSG between 2015 and 2021, referred for evaluating sleep-related breathing. Patient demographics, anthropometrics, and PSG data were recorded. Symptoms were evaluated using Epworth Sleepiness Scale and Pediatric Sleep Questionnaire. Pubertal staging was collected using Tanner Stage questionnaire. PSG parameters, symptoms and pubertal stage were compared between sexes with and without OSA.

RESULTS

Of 148 children, 61 (41%) had OSA. Within the OSA group, 41/62 (69%) were male (p = 0.002). Males with OSA reported higher Pediatric Sleep Questionnaire scores compared to males without OSA (0.38 ± 0.2 vs 0.23 ± 0.1; p = 0.002). Males with OSA reported more trouble breathing (p = 0.04) and mouth breathing (p = 0.008) compared to females with OSA. Females with OSA showed longer sleep onset latency (45.8 ± 40.6 min vs 22.4 ± 26.7; p = 0.02) and higher supine obstructive-apnea hypopnea index (32.9 ± 31.1 vs 20.4 ± 18.4 events/hour; p = 0.02) compared to males with OSA. A significant interaction was found between male sex and waist-to-height ratio (β = 15.34, R² = 0.18, p = 0.05).

CONCLUSIONS

Sex differences in symptoms and phenotype of OSA exist among children with obesity. Such information is beneficial for early diagnosis and management to mitigate adverse outcomes and comorbidities.

Prevalence, characteristics, and respiratory arousal threshold of positional obstructive sleep apnea in China: a large scale study from Shanghai Sleep Health Study cohort

Purpose

To evaluate the prevalence, characteristics, and respiratory arousal threshold (ArTH) of Chinese patients with positional obstructive sleep apnea (POSA) according to the Cartwright Classification (CC) and Amsterdam Positional Obstructive Sleep Apnea Classification (APOC).

Methods

A large-scale cross-sectional study was conducted in our sleep center from 2007 to 2018 to analyze the clinical and polysomnography (PSG) data of Chinese POSA patients. Low ArTH was defined based on PSG indices.

Results

Of 5,748 OSA patients, 36.80% met the CC criteria, and 42.88% the APOC criteria, for POSA. The prevalence of POSA was significantly higher in women than men (40.21% and 46.52% vs. 36.13% and 42.18% for CC and APOC, respectively). Chinese POSA patients had a lower apnea hypopnea index (AHI) and lower oxygen desaturation index, shorter duration of oxygen saturation (SaO₂) < 90%, and a higher mean SaO₂ and higher lowest SaO₂ value compared to subjects with non-positional OSA (NPOSA). More than 40% of the POSA patients had a low ArTH; the proportion was extremely high in the supine-isolated-POSA (si-POSA) group and APOC I group. In multivariate logistic regression analyses, higher mean SaO₂ and lower AHI during sleep were positive predictors of POSA.

Conclusions

According to the CC and APOC criteria, more than 1/3 of our Chinese subjects with OSA had POSA. Chinese POSA patients had less severe OSA and nocturnal hypoxia. Compared to NPOSA patients, significantly more patients with POSA had a low ArTH. A low ArTH may be an important endotype in the pathogenesis of POSA, especially in patients with si-POSA and APOC I. Further studies are necessary to develop personalized management strategies for POSA patients.

Trial registration: Chinese Clinical Trial Registry; URL: http://www.chictr.org.cn; No. ChiCTR1900025714 (retrospectively registered).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02141-3.

Body position during laboratory and home polysomnography compared to habitual sleeping position at home

STUDY OBJECTIVES

Supine-predominant obstructive sleep apnea (OSA) is highly prevalent. The proportion of time spent in the supine position may be overrepresented during polysomnography, which would impact on the apnea-hypopnea index (AHI) and have important clinical implications. We aimed to investigate the difference in body position during laboratory or home polysomnography compared to habitual sleep and estimate its effect on OSA severity. Secondary aims were to evaluate the consistency of habitual sleeping position and accuracy of self-reported sleeping position.

METHODS

Patients undergoing diagnostic laboratory or home polysomnography were recruited. Body position was recorded using a neck-worn device. Habitual sleeping position was the average time spent supine over 3 consecutive nights at home. Primary outcomes were the proportion of sleep time spent supine (% time supine) and AHI adjusted for habitual sleeping position.

RESULTS

Fifty-seven patients who underwent laboratory polysomnography and 56 who had home polysomnography were included. Compared to habitual sleep, % time supine was higher during laboratory polysomnography (mean difference 14.1% [95% confidence interval: 7.2-21.1]; P = .0002) and home polysomnography (7.1% [95% confidence interval 0.9-13.3]; P = .03). Among those with supine-predominant OSA, there was a trend toward lower adjusted AHI than polysomnography-derived AHI (P = .07), changing OSA severity in 31.6%. There was no significant between-night difference in % time supine during habitual sleep (P = .4). Self-reported % time supine was inaccurate (95% limits of agreement -49.2% to 53.9%).

CONCLUSIONS

More time was spent in the supine position during polysomnography compared to habitual sleep, which may overestimate OSA severity for almost one-third of patients with supine-predominant OSA.

CLINICAL TRIAL REGISTRATION

Registry: Australia and New Zealand Clinical Trials Registry (ANZCTR); Title: Sleeping position during sleep tests and at home; Identifier: ACTRN12618000628246; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374873&isReview=true.

CITATION

Yo SW, Joosten SA, Wimaleswaran H, et al. Body position during laboratory and home polysomnography compared to habitual sleeping position at home. J Clin Sleep Med. 2022;18(9):2103-2111.

Polysomnographic characteristics and predictors of positional obstructive sleep apnea in Japanese elderly

Sleep problems and obstructive sleep apnea (OSA) increase with age and disturb life in old age. Positional therapy is one option to treat OSA, but the differences in clinical pathophysiology between elderly and other age groups have not been fully investigated. We explored the pathophysiological features of sleep apnea, factors that are independently associated with positional OSA and the prevalence in elderly patients. We studied demographic and polysomnographic data of 85 elderly individuals with OSA (age ≥ 65 years) and 124 non-elderly patients with OSA (age, 20-64 years). The Amsterdam Positional OSA Classification (APOC) was used to evaluate positional OSA. Body mass index (BMI) and Epworth sleepiness scale were both significantly lower in the elderly group than in the non-elderly group, although apnea/hypopnea index (AHI) did not differ between groups. OSA severity affected total sleep time, sleep efficiency, and waking after sleep onset more in the elderly than in the non-elderly. AHI in the lateral position was significantly lower in elderly than in non-elderly, although AHI in the supine position was almost the same between two groups. The distribution of APOC 1 and 2 (lateral sleep effective) was significantly higher in the elderly than in the non-elderly. Relative factors such as BMI, rate of hypopnea, and lowest SpO2 associated with positional OSA in non-elderly groups did not differ significantly among APOC subgroups in elderly patients. Our findings are suggesting that characteristics of the positional OSA is different between elderly and younger-age OSA patients.

Comparison of polysomnographic and cephalometric parameters based on positional and rapid eye movement sleep dependency in obstructive sleep apnea

The aim of this study is to investigate the differences in polysomnographic and cephalometric features according to positional and rapid eye movement (REM) sleep dependencies in obstructive sleep apnea patients. Standard polysomnography and cephalometric analyses were performed on 133 OSA patients. The subjects were categorized into positional and non-positional, and REM-related and not-REM-related OSA groups according to positional and REM sleep dependency on severity of sleep apnea. Polysomnographic and cephalometric parameters were compared between groups. Positional and REM-related OSA patients showed significantly lower non-supine apnea-hypopnea index (AHI), non-REM (NREM) AHI and overall AHI and higher NREM oxygen saturation (SpO₂) and mean SpO₂ compared to non-positional and not-REM-related OSA patients, respectively. Cephalometric features between positional and non-positional OSA patients did not show any significant differences. However, REM-related OSA patients showed significantly larger inferior oral airway space and shorter perpendicular distance between mandibular plane and anterior hyoid bone and the distance between uvula and posterior nasal spine, and narrower maximum width of soft palate than not-REM-related OSA patients. Positional and REM-related OSA patients have lower severity of sleep apnea, suggesting the possibility of lower collapsibility of the upper airway. REM sleep dependency was associated with anatomical factors, while positional dependency did not show such a tendency.

Comparing the characteristics of positional and nonpositional sleep apnea patients among the Jordanian population

BACKGROUND:

Obstructive sleep apnea (OSA) is a common cause of sleep-disordered breathing with a large proportion of the patients exhibiting positional OSA (POSA). In this study, we aimed to evaluate the differences in the demographics, comorbidities, and polysomnographic features between POSA and non-POSA (NPOSA) in a Jordanian sample to further discern the propulsive elements for each group.

METHODS:

In this study, we evaluated 1037 adult patients with OSA. POSA was defined as an overall apnea and hypopnea index (AHI) >5, an overall AHI severity at least 1.4 times the nonsupine severity (overall/NS-AHI), and a minimum amount of time (i.e., 20 min) in the supine and nonsupine positions. To compare the clinical characteristics between POSA and NPOSA patients, statistical analyses were performed.

RESULTS:

The prevalence of POSA was 41.7%. In comparison to NPOSA patients, POSA patients had higher female sex prevalence, milder OSA, lower body mass index, lower hypertension prevalence, and lower hemoglobin A1C levels compared to NPOSA patients. Moreover, sleep efficiency, total sleep time, and supine sleep time were significantly higher in POSA patients. Nonsupine sleep time, total AHI, rapid eye movement (REM) AHI, non-REM (NREM) AHI, supine AHI, nonsupine AHI, left and right AHI, mean oxyhemoglobin saturation (SpO₂) awake, mean REM and NREM SpO₂, SpO₂ nadir, and time SpO₂ below 90% were significantly lower among POSA patients. The multivariate regression analysis showed that only female gender and hypertension were significantly associated with POSA.

CONCLUSION:

POSA is common among OSA patients and demonstrates different clinical characteristics in comparison to NPOSA. Future prospective studies are needed to better characterize the POSA patients and investigate the benefit of positional therapy.

Novel avenues to approach non-CPAP therapy and implement comprehensive OSA care

Recent advances in obstructive sleep apnoea (OSA) pathophysiology and translational research have opened new lines of investigation for OSA treatment and management. Key goals of such investigations are to provide efficacious, alternative treatment and management pathways that are better tailored to individual risk profiles to move beyond the traditional, continuous positive airway pressure (CPAP)-focused, "one size fits all", trial and error approach which is too frequently inadequate for many patients. Identification of different clinical manifestations of OSA (clinical phenotypes) and underlying pathophysiological phenotypes (endotypes), that contribute to OSA have provided novel insights into underlying mechanisms and have underpinned these efforts. Indeed, this new knowledge has provided the framework for precision medicine for OSA to improve treatment success rates with existing non-CPAP therapies such as mandibular advancement devices and upper airway surgery, and newly developed therapies such as hypoglossal nerve stimulation and emerging therapies such as pharmacotherapies and combination therapy. These concepts have also provided insight into potential physiological barriers to CPAP adherence for certain patients. This review summarises the recent advances in OSA pathogenesis, non-CPAP treatment, clinical management approaches and highlights knowledge gaps for future research. OSA endotyping and clinical phenotyping, risk stratification and personalised treatment allocation approaches are rapidly evolving and will further benefit from the support of recent advances in e-health and artificial intelligence.

Hot flashes, insomnia, and the reproductive stages: a cross-sectional observation of women from the EPISONO study

STUDY OBJECTIVES

To investigate the association of hot flashes and insomnia in women in premenopause and postmenopause.

METHODS

The study was performed using data from the São Paulo Epidemiological Sleep Study. Women in premenopause were classified as having regular menstrual cycles, being anovulatory, or using hormonal contraceptives. Women in menopause were classified as being in perimenopause, early postmenopause, or late postmenopause. Women reporting frequent insomnia symptoms and relevant daytime complaints were classified as having insomnia disorder. Polysomnography alterations suggestive of insomnia were also identified.

RESULTS

The frequency of hot flashes was 42% among women in postmenopause (mainly in early postmenopause) and 9% among women in premenopause (mainly anovulatory; P < .01). Approximately 18.7% had insomnia disorder, 48% had isolated insomnia symptoms, and 32.4% had polysomnography alterations. Comparing women in menopause with those in premenopause, the diagnosis of insomnia was similar (premenopause: 18.9% vs menopause: 17.5%), but women in menopause had more frequent isolated insomnia symptoms (premenopause: 43.9% vs menopause: 55.9%; P = .02) and polysomnography correlates of insomnia (premenopause: 26.5% vs menopause: 42.6%; P < .01). Hot flashes were more frequent among women with insomnia disorders (25.5%) and with isolated insomnia symptoms (23.0%) when compared with good sleepers (12.6%) in the entire sample (P = .01). Among women in late menopause, the prevalence of hot flashes was higher in both women with insomnia disorders (42.1%) and with isolated insomnia symptoms (37.5%) when compared with women who were good sleepers (14.3%; P = .05).

CONCLUSIONS

Hot flashes are associated with insomnia and polysomnography alterations suggestive of insomnia. The prevalence of hot flashes among women with insomnia disorder is especially high among women in late postmenopause.

CITATION

Hachul H, Castro LS, Bezerra AG, et al. Hot flashes, insomnia, and the reproductive stages: a cross-sectional observation of women from the EPISONO study. J Clin Sleep Med. 2021;17(11):2257-2267.

The Worsening of Positional Mild Obstructive Sleep Apnea over Time Is Associated with an Increase in Body Weight: Impact on Blood Pressure and Autonomic Nervous System

BACKGROUND

Most patients with mild obstructive sleep apnea (OSA) are positional dependent. Although mild OSA worsens over time, no study has assessed the natural course of positional mild OSA.

OBJECTIVES

The aim of this study was to evaluate the natural course of positional mild OSA, its most valuable progression predictor, and its impact on blood pressure (BP) and the autonomic nervous system (ANS).

METHODS

This retrospective observational cohort study enrolled 86 patients with positional mild OSA and 26 patients with nonpositional mild OSA, with a follow-up duration of 32.0 ± 27.6 months and 37.6 ± 27.8 months, respectively. Polysomnographic variables, BP, and ANS functions were compared between groups at baseline and after follow-up.

RESULTS

In patients with positional mild OSA after follow-up, the apnea/hypopnea index (AHI) increased (9.1 ± 3.3/h vs. 22.0 ± 13.2/h, p = 0.000), as did the morning systolic BP (126.4 ± 13.3 mm Hg vs. 130.4 ± 15.9 mm Hg, p = 0.011), and the sympathetic activity (49.4 ± 12.3% vs. 55.3 ± 13.1%, p = 0.000), while the parasympathetic activity decreased (50.6 ± 12.3% vs. 44.7 ± 13.1%, p = 0.000). The body mass index changes were the most important factor associated with AHI changes among patients with positional mild OSA (Beta = 0.259, adjust R2 = 0.056, p = 0.016, 95% confidence interval 0.425 and 3.990). The positional dependency disappeared over time in 66.3% of patients with positional mild OSA while 69.2% of patients with nonpositional mild OSA retained nonpositional.

CONCLUSIONS

In patients with positional mild OSA, disease severity, BP, and ANS regulation worse over time. Increased weight was the best predictor for its progression and the loss of positional dependency. Better treatments addressing weight control and consistent follow-up are needed for positional mild OSA.

Improving outcomes of hypoglossal nerve stimulation therapy: current practice, future directions and research gaps. Proceedings of the 2019 International Sleep Surgery Society Research Forum

Hypoglossal nerve stimulation (HGNS) has evolved as a novel and effective therapy for patients with moderate-to-severe obstructive sleep apnea (OSA). Despite positive published outcomes of HGNS, there exist uncertainties regarding proper patient selection, surgical technique, and the reporting of outcomes and individual factors that impact therapy effectiveness. According to current guidelines, this therapy is indicated for select patients, and recommendations are based on the Stimulation Therapy for Apnea Reduction (STAR) trial. Ongoing research and physician experiences continuously improve methods to optimize the therapy. An understanding of the way in which airway anatomy, OSA phenotypes, individual health status, psychological conditions and comorbid sleep disorders influence the effectiveness of HGNS is essential to improve outcomes and expand therapy indications. This manuscript presents discussions on current evidence, future directions, and research gaps for HGNS therapy from the 10th International Surgical Sleep Society expert research panel.

Efficacy and long-term follow-up of positional therapy by vibrotactile neck-based device in the management of positional OSA

STUDY OBJECTIVES

Different therapeutic strategies have been investigated for the treatment of positional obstructive sleep apnea, but more evidence is needed about efficacy and compliance. The objective of this study was to describe the efficacy of vibrotactile neck-based treatment in patients with positional obstructive sleep apnea with different degrees of obstructive sleep apnea severity who were followed for 6 months.

METHODS

This is a retrospective study including 162 patients with positional obstructive sleep apnea undergoing vibrotactile neck-based positional therapy. We compared polysomnographic data obtained at baseline and during positional therapy after 1 month. We performed a subgroup analysis based on obstructive sleep apnea severity. Furthermore, we analyzed follow-up data in 84/162 (51.8%) patients with particular focus on discontinuation and complications related to the device.

RESULTS

We observed a significant difference between mean baseline obstructive apnea-hypopnea index (OAHI; 21.9 ± 9.9 events/h) and during positional therapy (12 ± 9.2 events/h; P < .01). Moreover, 87/162 (54.9%) patients showed a reduced baseline OAHI of at least 50% and 38/162 (23.4%) achieved complete disease control (OAHI < 5 events/h). At subgroup analysis, at least 50% reduction from baseline OAHI was observed in 56.8% of patients with mild, 55% with moderate, and 47.4% with severe OAHI, whereas complete control of disease was achieved in 50% of patients with mild, 22.5% with moderate, and 7.9% with severe OAHI. At a 6-month follow-up, only 35/84 patients (41.6%) were regularly using the device, with a mean of 5.9 ± 1.2 days per week.

CONCLUSIONS

Our results on the efficacy and long-term adherence to vibrotactile neck-based positional therapy showed that positional therapy can be an efficient first-line treatment option for mild positional obstructive sleep apnea and in selected cases of moderate disease. Long-term compliance is limited because of complications and low satisfaction in some patients.

Sleep in Older Adults and Its Possible Relations With COVID-19

Since the beginning of the COVID-19 pandemic, older adults have been found to be a highly vulnerable group, with a higher prevalence of severe cases and negative outcomes. Research has focused on the reasons why older adults are at greater risk; Sleep-related factors have been suggested as one possible explanation for this. An individual's sleep pattern undergoes significant changes over the course of their life. In older adults a specific sleep profile can be observed, one characterized by advanced sleep timing, a morningness preference, longer sleep-onset latency, shorter overall sleep duration, increased sleep fragmentation, reduced slow-wave sleep and, increased wake time after sleep onset. Additionally, an increased prevalence of sleep disorders can be observed, such as obstructive sleep apnea and insomnia. Previous research has already linked sleep disorders (especially sleep apnea) with COVID-19, but few studies have focused specifically on the older population. We believe that the intrinsic sleep patterns of older adults, and the prevalence of sleep disorders in this population, may be important factors that could explain why they are at a greater risk of negative COVID-19 outcomes. In this review, we discuss the relationship between sleep and COVID-19 among older adults, focusing on three different aspects: (1) Sleep-related issues that might increase the likelihood of getting infected by SARS-COV-2; (2) Sleep disturbances that might increase the predisposition to worse COVID-19 prognosis and outcomes; and (3) COVID-19-related aspects affecting community-dwelling older adults, such as social isolation, quarantine, and home confinement, among others, that might impact sleep.

Positional obstructive sleep apnea within a large multicenter French cohort: prevalence, characteristics, and treatment outcomes

STUDY OBJECTIVES

To assess, in a large cohort of patients with obstructive sleep apnea, the factors that are independently associated with positional obstructive sleep apnea (POSA) and exclusive POSA (e-POSA) and determine their prevalence. The secondary objective was to evaluate the outcome of positive airway pressure (PAP) therapy for patients with POSA and e-POSA.

METHODS

This retrospective study included 6,437 patients with typical mild-to-severe OSA from the Pays de la Loire sleep cohort. Patients with POSA and e-POSA were compared to those with non-POSA for clinical and polysomnographic characteristics. In a subgroup of patients (n = 3,000) included in a PAP follow-up analysis, we determined whether POSA and e-POSA phenotypes were associated with treatment outcomes at 6 months.

RESULTS

POSA and e-POSA had a prevalence of 53.5% and 20.1%, respectively, and were independently associated with time in supine position, male sex, younger age, lower apnea-hypopnea index and lower body mass index. After adjustment for confounding factors, patients with POSA and e-POSA had a significantly lower likelihood of treatment adherence (PAP daily use ≥ 4 h) at 6 months and were at higher risk of PAP treatment withdrawal compared to those with non-POSA.

CONCLUSIONS

The prevalence and independent predictors of POSA and e-POSA were determined in this large clinical population. Patients with POSA and e-POSA have lower PAP therapy adherence, and this choice of treatment may not be optimal. Thus, there is a need to offer these patients an alternative therapy.

Body Mass Index Reduction and Selected Cardiometabolic Risk Factors in Obstructive Sleep Apnea: Meta-Analysis

Although clinical studies have been carried out on the effects of weight reduction in sleep apnea patients, no direct link has been shown between weight reduction and changes in cardio-metabolic risk factors. We aimed to analyze changes in the apnea–hypopnea index and selected cardio-metabolic parameters (total cholesterol, triglycerides, glucose, insulin, blood pressure) in relation to the reduction in body mass index in obstructive sleep apnea patients. Medline, Web of Science and Cochrane databases were searched to combine results from individual studies in a single meta-analysis. We identified 333 relevant articles, from which 30 papers were assigned for full-text review, and finally 10 (seven randomized controlled trials and three nonrandomized studies) were included for data analysis. One unit of body mass index reduction was found to significantly influence changes in the apnea–hypopnea index (−2.83/h; 95% CI: −4.24, −1.41), total cholesterol (−0.12 mmol/L; 95% CI: −0.22, −0.01), triglycerides (−0.24 mmol/L; 95% CI: −0.46, −0.02), fasting insulin (−7.3 pmol/L; 95% CI: −11.5, −3.1), systolic (−1.86 mmHg; 95% CI: −3.57, −0.15) and diastolic blood pressure (−2.07 mmHg; 95% CI: −3.79, −0.35). Practical application of lifestyle modification resulting in the reduction of one unit of body mass index gives meaningful changes in selected cardio-metabolic risk factors in obstructive sleep apnea patients.

Standardized framework to report on the role of sleeping position in sleep apnea patients

PURPOSE

Sleep apnea is a multifactorial illness which can be differentiated in various physiological phenotypes as a result of both anatomical and non-anatomical contributors (e.g., low respiratory arousal threshold, high loop gain). In addition, the frequency and duration of apneas, in the majority of patients with OSA, are influenced by sleeping position. Differences in characteristics between non-positional patients (NPP) and positional patients (PP) suggest another crucial phenotype distinction, a clinical phenotype focusing on the role of sleeping position on sleep apnea. Since this clinical phenotype distinction has therapeutic implications, further research is necessary to better understand the pathophysiology behind this phenotypic trait and to improve management of PP. Therefore, we suggest a standardized framework that emphasizes the role of sleeping position when reporting clinical and research data on sleep apnea.

METHODS

We identified 5 key topics whereby a standardized framework to report on the role of sleeping position would be of added value: (1) sleep study data, (2) anatomical, morphological and physiological factors, (3) drug-induced sleep endoscopy (DISE) findings, (4) sleep apnea management, and (5) effectiveness versus efficacy of positional therapy in sleep apnea management. We performed a literature search to identify evidence to describe and support the rationale behind these 5 main recommendations.

RESULTS

In this paper, we present the rationale behind this construct and present specific recommendations such as reporting sleep study indices (disease severity) and sleep time spent in various sleeping positions. The same is suggested for DISE findings and effect of treatment. Sleep study indices (disease severity), anatomical, morphological, and physiological factors in sleep apnea patients should be reported separately for PP and NPP.

CONCLUSION

Applying these suggestions in future research will improve patient care, assist in better understanding of this dominant phenotype, and will enhance accurate comparisons across studies and future investigations.

Role of drug-induced sleep endoscopy in evaluation of positional vs non-positional OSA

Background

The study aimed to evaluate the anatomical differences between positional and non-positional OSA, and to identify the potential predictors for distinguishing between these two types of OSA.

Methods

A cross-sectional study of 230 consecutive patients with OSA undergoing DISE (Drug-induced Sleep Endoscopy) was carried out at a tertiary academic medical center. The factors correlating with positional and non-positional OSA were analyzed, including clinical characteristics, polysomnography data, and DISE findings.

Results

Univariate analysis revealed that non-positional dependency was correlated with a higher BMI (p < 0.001), neck circumference (p < 0.001), modified Mallampati score (p = 0.003), AHI (p < 0.001), degree of velum concentric collapse (p = 0.004), degree of oropharyngeal lateral wall collapse (p < 0.001), and degree of tongue base anteroposterior collapse (p = 0.004). Multivariate analysis revealed that oropharyngeal lateral wall collapse (OR = 1.90, p = 0.027) was the only anatomical factor significantly predicted non-positional dependency in OSA patients. AHI (OR = 1.04, p < 0.001), although significant, made only a marginal contribution to the prediction of non-positional dependency.

Conclusions

Oropharyngeal lateral wall collapse was identified as the only anatomical predictor for non-positional dependency in OSA patients. Therefore, further treatment modalities should address the distinct anatomical trait between positional and non-positional OSA.

Graphical abstract

Assessment of Nocturnal Autonomic Cardiac Imbalance in Positional Obstructive Sleep Apnea. A Multiscale Nonlinear Approach

Positional obstructive sleep apnea (POSA) is a major phenotype of sleep apnea. Supine-predominant positional patients are frequently characterized by milder symptoms and less comorbidity due to a lower age, body mass index, and overall apnea-hypopnea index. However, the bradycardia-tachycardia pattern during apneic events is known to be more severe in the supine position, which could affect the cardiac regulation of positional patients. This study aims at characterizing nocturnal heart rate modulation in the presence of POSA in order to assess potential differences between positional and non-positional patients. Patients showing clinical symptoms of suffering from a sleep-related breathing disorder performed unsupervised portable polysomnography (PSG) and simultaneous nocturnal pulse oximetry (NPO) at home. Positional patients were identified according to the Amsterdam POSA classification (APOC) criteria. Pulse rate variability (PRV) recordings from the NPO readings were used to assess overnight cardiac modulation. Conventional cardiac indexes in the time and frequency domains were computed. Additionally, multiscale entropy (MSE) was used to investigate the nonlinear dynamics of the PRV recordings in POSA and non-POSA patients. A total of 129 patients (median age 56.0, interquartile range (IQR) 44.8-63.0 years, median body mass index (BMI) 27.7, IQR 26.0-31.3 kg/m2) were classified as POSA (37 APOC I, 77 APOC II, and 15 APOC III), while 104 subjects (median age 57.5, IQR 49.0-67.0 years, median BMI 29.8, IQR 26.6-34.7 kg/m2) comprised the non-POSA group. Overnight PRV recordings from positional patients showed significantly higher disorderliness than non-positional subjects in the smallest biological scales of the MSE profile (τ = 1: 0.25, IQR 0.20-0.31 vs. 0.22, IQR 0.18-0.27, p < 0.01) (τ = 2: 0.41, IQR 0.34-0.48 vs. 0.37, IQR 0.29-0.42, p < 0.01). According to our findings, nocturnal heart rate regulation is severely affected in POSA patients, suggesting increased cardiac imbalance due to predominant positional apneas.

Lying posture affects sleep structures and cortical activities: a simultaneous EEG-fMRI imaging of the sleeping and waking brain

Lying posture influences both neural activity and cognitive performance, and it is essential to sleep hygiene. Whereas, no neuroimaging research has investigated the effect of lying position on brain activity in waking and sleeping conditions. Therefore, we recruited 35 participants to perform a within-participant simultaneous EEG-fMRI recording with lying supine and lateral postures. Our results showed that sleep onset latency (SOL) was affected by both sleep position preference (SPP) and lying poses. SOL in supine was significantly shorter than that in lateral posture. The correlation analysis between SPP and sleep parameters indicated that individuals who prefer supine had less SOL and N2 sleep durations. However, we did not find this significant correlation in lateral-prefer individuals. Besides, different sleep positions mainly caused an alteration of the differences in brain activity patterns. In supine posture, the brain activities in the left precuneus, and anterior cingulate cortex were greater than those in lateral position. However, in the lateral posture, the status was just the opposite. Finally, we also found that the right putamen was sensitive to habitual sleep posture in the awake state. The participants who prefer to lie supine tend to have higher activity in the putamen. Our study may help with the understanding of the contribution of lying posture on brain activity and its relationship with posture preference in sleep.

Dental sleep medicine: Time to incorporate sleep apnoea education in the dental curriculum

Dental sleep medicine is a discipline that includes conditions such as sleep breathing disorders (eg snoring and sleep apnoea), sleep bruxism, orofacial pain and sleep-related complaints, and to some extent gastro-oesophageal reflux disorder and/or insomnia. Obstructive sleep apnoea (OSA) is a life-threatening condition that dentists need to identify and manage when indicated in order to increase patient well-being and to be taken in consideration in the dental curriculum. The main objective of this paper is to highlight the relevance of dental sleep medicine in the context of dental education, and to discuss potential educational content for integration in the dental curriculum with a focus on OSA, a condition that is not yet integrated in many dental training curricula around the world.

A stepwise titration protocol for oral appliance therapy in positional obstructive sleep apnea patients: proof of concept

Purpose

In patients with positional obstructive sleep apnea (POSA), oral appliance therapy (OAT) is among the first-line treatments. The aim of this study was to evaluate the effects of a new standardized stepwise titration protocol for OAT in a group of patients with POSA.

Methods

This was an observational intervention trial. Patients who were previously randomized to the OAT intervention arm of a comparison study comprised the subjects for this study. These patients, who had mild to moderate POSA, were assessed after 3 and 12 months for treatment efficacy, objective adherence by temperature microsensor, and side effects. The titration of OAT was performed using a standardized stepwise titration protocol including advancement levels of 60%, 75%, and 90% of the maximum mandibular protrusion. The optimal advancement level per individual was based on a weighted compromise between efficacy and side effects.

Results

In total, 36 patients were included and all completed the titration protocol after 3 months. At baseline, the OAT was set at 60% of the maximal mandibular protrusion position. At a 3-month evaluation, the advancement remained at 60% in 16 patients (44%) and reached 75% advancement in 20 patients (56%). Mean apnea-hypopnea index decreased from 12.9 events per hour (9.1–16.7) to 6.9 (3.7–10.3) (P < 0.001), and median objective adherence was 97.4 (61.4–100.00) after 3 months. The 12-month analysis showed consistent results and good OAT tolerance. Six patients (16.7%) terminated OAT and one patient (2.8%) was lost to follow-up.

Conclusions

This standardized stepwise titration protocol for OAT showed good efficacy, good OAT tolerance, and good objective adherence in patients with mild to moderate POSA. Therefore, the protocol is recommended in research projects to improve standardization of methods between studies and in clinical practice for its practical feasibility.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02045-w) contains supplementary material, which is available to authorized users.

Long-Term Subjective Outcomes of Barbed Reposition Pharyngoplasty for Obstructive Sleep Apnea Syndrome Treatment

Background: The purpose of this study was to evaluate long-term subjective outcomes of barbed reposition pharyngoplasty for obstructive sleep apnea syndrome (OSAS) treatment using a specific questionnaire, the Palate Postoperative Problem Score (PPOPS). Methods: 140 patients who underwent barbed reposition pharyngoplasty (BRP) surgery in the Morgagni Pierantoni Hospital of Forlì, Italy were enrolled in the study. Postoperative outcomes were evaluated in a short- and long-term follow-up using the PPOPS questionnaire. The average period of follow-up was 26 months. All patients received the PPOPS questionnaire by telephone in a period between April and August 2019. Results: 51% of patients complained of swallowing problems after surgery. In 91% of cases, the problem cleared up spontaneously. At the time of the interview, only 9% of patients had a residual swallowing difficult. At the time of PPOPS evaluation, rhinolalia was observed in 8% of patients, whereas nose regurgitation was present in 2% of patients. In 20% of patients, the foreign body sensation was present during follow-up. The value of apnea–hypopnea index (AHI) reduced from the preoperative value of 31.5 to the postoperative value of 11.4. Conclusions: BRP surgery proved to be an effective technique, appreciated by the majority of patients. Use of the PPOPS questionnaire has demonstrated that the BRP technique seems to ensure efficacy and lower morbidity, with few complications after surgery.

Positional Obstructive Sleep Apnea Syndrome in Elderly Patients

Background The purpose of this study was to evaluate the prevalence of position-dependent obstructive sleep apnea (POSA) in elderly patients (≥65 years old). Adult (range 19-65 years old) and elderly patients were also compared in order to show differences in the incidence of POSA between these two groups of patients. Methods A prospective bi-center study was performed between January 2018 and May 2019. A total of 434 participants underwent polysomnography (PSG) study at home (Embletta MPR). Body position during the PSG recordings was determined. Patients were subdivided in two groups: those aged between 19 and 65 years old (adult patients) and ≥65 years old (elderly patients). POSA patients were defined using Cartwright’s system, Bignold classification, and the new Amsterdam Positional OSA Classification (APOC). Results The prevalence of POSA in elderly patients differed according to the classification system used: 49.3% using Cartwright’s classification system, 20.5% with the Bignold classification, and 22.6%, 38.9%, and 5.4% of APOC 1, APOC 2, and APOC3 sub-classes were respectively identified for the APOC classification system. No difference between adult and elderly patients regarding the prevalence of POSA was observed. No statistical differences emerged between the two groups of patients in terms of supine (p = 0.9) and non-supine AHI (p = 0.4). Conclusions A significant number of elderly patients could be considered treatable with positional therapy according to the APOC classification. However, the efficacy and applicability of positional therapy in elderly patients must be confirmed by further research.

Comparing treatment effects of a convenient vibratory positional device to CPAP in positional OSA: a crossover randomised controlled trial

OBJECTIVES

Up to 77% of patients with obstructive sleep apnoea (OSA) have positional OSA (POSA) but traditional positional therapy (PT) methods have failed as they were poorly tolerated. New convenient vibratory PT devices have been invented but while recent studies suggest high treatment efficacy and adherence, there are no published data comparing these devices directly with continuous positive airway pressure (CPAP). Our objective is to evaluate if a convenient vibratory PT device is non-inferior to CPAP in POSA treatment.

METHODS

In this crossover randomised controlled trial, we enrolled patients with POSA with significant daytime sleepiness (Epworth Sleepiness Scale (ESS)≥10). POSA diagnosis was based on: (1) total Apnoea/Hypopnoea Index (AHI)>10/hour and non-supine AHI<10/hour (2) supine AHI≥2 × non-supine AHI. Patients used their initial allocated devices (PT or CPAP) for 8 weeks before crossing to the alternative intervention after a 1 week washout. The primary aim is to measure changes in ESS between the two treatments. Secondary outcomes include sleep study parameters and patient treatment preference (ClinicalTrials.gov: NCT03125512).

RESULTS

40 patients completed the trial between April 2017 and December 2018. Difference in ESS after 8 weeks of device use (PT minus CPAP) was 2.0 (95% CI 0.68 to 3.32), exceeding our predetermined non-inferiority margin of 1.5. AHI on CPAP was lower than with PT (4.0±3.2 vs 13.0±13.8 events/hour, respectively, p=0.001), although both were lower than at baseline. Time spent supine was significantly lower with PT than CPAP (p<0.001). 60% of patients preferred CPAP, 20% preferred PT, while 20% preferred neither device.

CONCLUSIONS

The non-inferiority ESS endpoint for PT compared with CPAP was not met and the results were inconclusive. Future trials with larger sample sizes or in less symptomatic patients are warranted to provide further insight into the role of these new vibratory PT devices.

Positional Sleep Apnea Among Regional and Remote Australian Population and Simulated Positional Treatment Effects

PURPOSE

To assess the prevalence of positional sleep apnea (POSA) and its predictors in patients diagnosed to have obstructive sleep apnea (OSA) in the regional and remote population of the Northern Territory of Australia over a two-year study period (2018 and 2019).

PATIENTS AND METHODS

Of the total 1463 adult patients who underwent a diagnostic polysomnography (PSG), 946 patients were eligible to be included in the study, of them, 810 consecutive patients with OSA (Apnea-Hypopnea Index (AHI) ≥ 5) who slept >4 h and had ≥30 min sleep in both supine and lateral positions were assessed. Patients were considered to have POSA if supine AHI to lateral AHI ratio ≥2. The likely comparative impact of use of continuous positive airway therapy (CPAP) or positional therapy (PT) on disease severity was evaluated using model simulation.

RESULTS

A total of 495/810 (61%) patients had POSA, the majority were males (68% vs 60%, p=0.013) and non-Indigenous Australians (93% vs 87%, p=0.004). POSA patients were younger (mean difference 2.23 years (95% CI 0.27, 4.19)), less obese (BMI mean difference 3.06 (95% CI 2.11, 4.01)), demonstrated less severe OSA (p < 0.001) and a greater proportion reported alcohol consumption (72% vs 62%, p=0.001) as compared to those with non-POSA. Using the simulation model, if patients with POSA use PT two-thirds (323/495, 65%) would obtain significant improvement of their OSA severity, with one in five (92/495, 19%) displaying complete resolution. Comparing this to simulated CPAP therapy, where the majority (444/495, 90%) will show significant improvement, and one-third (162/495, 33%) will display complete resolution.

CONCLUSION

POSA needs to be routinely recognised and positional therapy integrated in practice especially in the remote regions and in the developing world when effective methods are in place to monitor positional therapy.

Obstructive Sleep Apnea: Do Positional Patients Become Nonpositional Patients With Time?

OBJECTIVES

Obstructive sleep apnea (OSA) patients with breathing abnormalities only or mainly in the supine posture are designated positional patients (PPs), whereas nonpositional patients (NPPs) have many breathing abnormalities in both lateral and supine postures. Positional therapy (PT), the avoidance of the supine posture during sleep, is the obvious treatment for PPs. The stability over time of being PP and leading factors that are involved in converting a PP to an NPP are addressed.

METHODS

We analyzed polysomnographic (PSG) recordings of 81 consecutive adult patients with OSA who were judged to be PPs at the first PSG evaluation, and their follow-up PSGs were obtained after an average period of 6.6 years.

RESULTS

The follow-up PSGs indicated that 57 PPs (70.4%) remained PPs, whereas 24 (29.6 %) converted to NPPs. Among PPs and NPPs, body mass index (P ≤ 0.05), overall Apnea-Hypopnea Index (AHI, P ≤ 0.087), and lateral AHI (P ≤ 0.046) increased and minimum SpO₂ during rapid eye movement (REM) sleep (P ≤ 0.028) decreased significantly during the follow-up. However, among patients who became NPPs, the changes in these parameters were significantly (P ≤ 0.05) more pronounced compared to the patients who remained PPs.

CONCLUSION

After an average of 6.6 years, 70.4% of PPs remained PPs. Therefore, if adherence for PT is good, they could continue to benefit from this therapy. For those who turned to NPPs, PT will not be the optimal treatment anymore; thus, these patients should be frequently monitored. Furthermore, an early treatment of PPs with PT would be highly beneficial to prevent worsening of their OSA.

LEVEL OF EVIDENCE

2b Laryngoscope, 130:2263-2268, 2020.

Critical Issues in Dental and Medical Management of Obstructive Sleep Apnea

This critical review focuses on obstructive sleep apnea (OSA) and its management from a dental medicine perspective. OSA is characterized by ≥10-s cessation of breathing (apnea) or reduction in airflow (hypopnea) ≥5 times per hour with a drop in oxygen and/or rise in carbon dioxide. It can be associated with sleepiness and fatigue, impaired mood and cognition, cardiometabolic complications, and risk for transportation and work accidents. Although sleep apnea is diagnosed by a sleep physician, its management is interdisciplinary. The dentist’s role includes 1) screening patients for OSA risk factors (e.g., retrognathia, high arched palate, enlarged tonsils or tongue, enlarged tori, high Mallampati score, poor sleep, supine sleep position, obesity, hypertension, morning headache or orofacial pain, bruxism); 2) referring to an appropriate health professional as indicated; and 3) providing oral appliance therapy followed by regular dental and sleep medical follow-up. In addition to the device features and provider expertise, anatomic, behavioral, demographic, and neurophysiologic characteristics can influence oral appliance effectiveness in managing OSA. Therefore, OSA treatment should be tailored to each patient individually. This review highlights some of the putative action mechanisms related to oral appliance effectiveness and proposes future research directions.

Polysomnography and sleep position, a Heisenberg phenomenon? : A large-scale series

BACKGROUND

The severity of position-dependent obstructive sleep apnea (POSA) depends on the nonsupine and supine apnea-hypopnea index (AHI) as well as the time spent in supine position. The latter in particular is susceptible to variation. Several small-scale studies suggest that wearing polysomnography (PSG) apparatus leads to an increase in supine sleeping position.

OBJECTIVES

The aim of this study was to evaluate the effect of wearing PSG apparatus on sleeping position and on OSA severity.

MATERIAL AND METHODS

A large-scale, retrospective study was performed, including a consecutive series of POSA and non-apneic snoring patients who were prescribed positional therapy (Sleep Position Trainer [SPT]). The effect of wearing PSG apparatus on sleeping position was evaluated by comparing body position during the PSG night and inactive (diagnostic) phase of SPT.

RESULTS

The mean percentage of total recording time (TRT) in supine position was 43.1% during the PSG night phase compared with 28.6% of TRT during the inactive (diagnostic) phase of SPT; i.e., a significant decrease of 33.6% (p < 0.001). When adjusting the AHI using TRT in different sleeping positions measured with the SPT, the median AHI decreased from 13.3/h (9.0-20.4) to 10.3/h (6.8-16.2); p < 0.001. When using the adjusted AHI, 33% (N = 66) of all patients had a change in OSA severity.

CONCLUSIONS

The results of this study indicate that wearing PSG apparatus leads to an increase in the percentage of supine sleeping position causing an overestimation of OSA severity, especially in patients with POSA. This can have significant impact on both clinical and scientific practice.

The influence of position-dependency on surgical success in sleep apnea surgery - a systematic review

PURPOSE

To evaluate the influence of position-dependency on surgical success of upper airway (UA) surgery in obstructive sleep apnea (OSA) patients.

METHODS

Systematic review.

RESULTS

Two prospective cohort studies and seven retrospective cohort studies were included in this review. Despite the importance of the subject, it remains unclear whether position-dependency is a predictor for surgical success. No differences were found in surgical success rate between non-positional (NPP) and positional (PP) OSA patients undergoing uvulopalatopharyngoplasty/Z-palatoplasty with or without radiofrequent thermotherapy of the tongue, isolated tongue base or multilevel surgery and hypoglossal nerve stimulation. In one study PP undergoing relocation pharyngoplasty had a greater chance of surgical success. In the majority of the remaining studies, surgical success was in favor of NPP. Furthermore, in the vast part of included studies, the effect of UA surgery was suggested to be greater in the lateral position than supine position.

CONCLUSION

Although preoperative characteristics in PP (e.g., lower BMI and AHI) seem to be in favor for higher surgical success compared to NPP, it remains unclear whether position-dependency is a predictor for surgical outcome. It is suggested that the largest differences and expected preoperative and postoperative changes occur in non-supine AHI. In PP, the preoperative non-supine AHI is already lower compared to NPP suggesting a lower chance of surgical success in PP.

Prevalence and characteristics of positional obstructive sleep apnea (POSA) in patients with severe OSA

PURPOSE

We assessed the prevalence of positional patients (PPs) and the main predictors of positional dependency in severe obstructive sleep apnea (OSA). A simulated effect of positional therapy (PT) vs. continuous positive airway pressure (CPAP) was also assessed.

METHODS

Polysomnographic recordings of 292 consecutive patients with severe OSA (Apnea-Hypopnea Index (AHI) ≥ 30) who slept > 4 h and had ≥ 30 min sleep in both supine and lateral positions were assessed. PPs were defined to have a supine AHI/lateral AHI ratio ≥ two and non-positional patients (NPPs) a supine AHI/lateral AHI ratio < two.

RESULTS

A total of 35.3% of the severe OSA patients were PPs. They were less obese and had less severe OSA (p < 0.001) compared with NPPs. The percentage of total apnea-hypopnea time from total sleep time (AHT%) was the most significant predictor for positional dependency. By sleeping in the lateral posture (i.e. after simulated PT), 78 (75.7%) PPs obtained significant improvement of their OSA severity and 9 (8.7%) of them became "non-OSA". Moreover, if CPAP was used only for 50% of total sleep time, 53 patients (18.2%) gained more benefit from avoiding the supine posture than from CPAP therapy.

CONCLUSIONS

More than a third of the studied severe OSA patients were PPs. These patients could achieve a significant decrease in the number and severity of apneas and hypopneas by adopting the lateral posture, suggesting that PT may be a valuable therapy for a significant portion of these severe OSA patients who for whatever reason are not being treated by CPAP.

TRIAL REGISTRY

ClinicalTrials.gov Identifier: NCT03232658.

NightBalance Sleep Position Treatment Device Versus Auto-Adjusting Positive Airway Pressure for Treatment of Positional Obstructive Sleep Apnea

STUDY OBJECTIVES

Compare treatment efficacy and objective adherence between the NightBalance sleep position treatment (SPT) device and auto-adjusting positive airway pressure (APAP) in patients with exclusive positional obstructive sleep apnea (ePOSA) defined as a supine apnea-hypopnea index (sAHI) ≥ 2 times the nonsupine AHI (nsAHI) and a nsAHI < 10 events/h.

METHODS

This prospective multicenter randomized crossover trial enrolled treatment naive participants with ePOSA (AHI ≥ 15 events/h and nsAHI < 10 events/h) or (AHI > 10 and < 15 events/h with daytime sleepiness and nsAH < 5 events/h). Polysomnography and objective adherence determination (device data) were performed at the end of each 6-week treatment. Patient device preference was determined at the end of the study.

RESULTS

A total of 117 participants were randomized (58 SPT first, 59 APAP first). Of these, 112 started treatment with the second device (adherence cohort) and 110 completed the study (AHI cohort). The AHI on SPT was higher (mean ± standard deviation, 7.29 ± 6.8 versus 3.71 ± 5.1 events/h, P < .001). The mean AHI difference (SPT-APAP) was 3.58 events/h with a one sided 95% confidence interval upper bound of 4.96 events/h (< the prestudy noninferiority margin of 5 events/h). The average nightly adherence (all nights) was greater on SPT (345.3 ± 111.22 versus 286.98 ± 128.9 minutes, P < .0001). Participants found the SPT to be more comfortable and easier to use and 53% reported a preference for SPT assuming both devices were equally effective.

CONCLUSIONS

Treatment with SPT resulted in non-inferior treatment efficacy and greater adherence compared to APAP in ePOSA suggesting that SPT is an effective treatment for this group.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: The POSAtive Study: Study for the Treatment of Positional Obstructive Sleep Apnea; Identifier: NCT03061071; URL: https://clinicaltrials.gov/ct2/show/NCT03061071.