Relationship between surface facial dimensions and upper airway structures in obstructive sleep apnea

The Global Burden of Obstructive Sleep Apnea

This study reviewed the global prevalence, health and socioeconomic impact, and management approaches of obstructive sleep apnea. The narrative review examined three key dimensions: (1) worldwide OSA prevalence across different regions, accounting for variations in diagnostic standards; (2) OSA's effects on health outcomes and socioeconomic conditions across diverse populations and healthcare systems; and (3) current global approaches to OSA diagnosis, treatment, and public health management. Despite advances in diagnosis and treatment, a large proportion of OSA cases remain undiagnosed or inadequately managed. The findings show that untreated OSA significantly increases public safety risks, particularly regarding motor vehicle and occupational accidents, while also creating a substantial pool of patients at high risk for systemic complications with severe impacts on overall health. There is a critical need for increased public awareness, universal screening approaches, and integrated care strategies to address this global health challenge and reduce its considerable socioeconomic burden. Our review uniquely addresses global disparities in OSA prevalence, clarifies the health and socioeconomic impacts that remain underexplored in the current literature, and suggests concrete strategies for public health and clinical management improvement worldwide.

Expert consensus on orthodontic treatment of protrusive facial deformities

Protrusive facial deformities, characterized by the forward displacement of the teeth and/or jaws beyond the normal range, affect a considerable portion of the population. The manifestations and morphological mechanisms of protrusive facial deformities are complex and diverse, requiring orthodontists to possess a high level of theoretical knowledge and practical experience in the relevant orthodontic field. To further optimize the correction of protrusive facial deformities, this consensus proposes that the morphological mechanisms and diagnosis of protrusive facial deformities should be analyzed and judged from multiple dimensions and factors to accurately formulate treatment plans. It emphasizes the use of orthodontic strategies, including jaw growth modification, tooth extraction or non-extraction for anterior teeth retraction, and maxillofacial vertical control. These strategies aim to reduce anterior teeth and lip protrusion, increase chin prominence, harmonize nasolabial and chin-lip relationships, and improve the facial profile of patients with protrusive facial deformities. For severe skeletal protrusive facial deformities, orthodontic-orthognathic combined treatment may be suggested. This consensus summarizes the theoretical knowledge and clinical experience of numerous renowned oral experts nationwide, offering reference strategies for the correction of protrusive facial deformities.

The future of paediatric obstructive sleep apnoea assessment: Integrating artificial intelligence, biomarkers, and more

Assessing obstructive sleep apnoea (OSA) in children involves various methodologies, including sleep studies, nocturnal oximetry, and clinical evaluations. Previous literature has extensively discussed these traditional methods. Despite this, there is no consensus on the optimal screening method for childhood OSA, further complicated by the complexity and limited availability of diagnostic polysomnography (PSG). Recent advancements, such as the integration of artificial intelligence, biomarkers, 3D facial photography, and wearable technology, offer promising alternatives for early detection and more accurate diagnosis of OSA in children. This article provides a comprehensive review of these innovative techniques, highlighting their potential to enhance diagnostic accuracy and overcome the limitations of current methods. With an emphasis on cutting-edge technologies and emerging biomarkers, we discuss the future directions for paediatric OSA assessments and their potential to revolutionise clinical practice.

Sleep disorders in individuals with dentofacial deformities: a preliminary study on the relationship with sex and serotonin levels

PURPOSE

It has been suggested that dentofacial deformities (DFD) can impair sleep quality. This pilot study aimed at evaluating sleep disorders in individuals with DFD before orthognathic surgery, correlating the clinical findings with salivary biomarker levels.

METHODS

This cross-sectional study enrolled ten males and ten females with DFD diagnoses under orthodontic treatment preceding orthognathic surgery. The participants responded to the Pittsburgh Sleep Quality Index (PSQI), the Epworth Sleepiness Scale (ESS), and the Fletcher and Luckett Sleep Questionnaire (FLSQ). Obstructive sleep apnea (OSA) was examined by the Home Sleep Apnea Test (HSAT). The salivary levels of interleukin-1β (IL-1β), glutamate, and serotonin were measured.

RESULTS

85% of individuals presented PSQI and FLSQ scores indicative of sleep alterations. Females had higher scores in part 2 of the FLSQ instrument, referring to sleepiness-associated complaints. HSAT analysis revealed a low number of symptomatic OSA individuals, with three males demonstrating altered oxygen desaturation rates. There was a significant negative correlation between the salivary levels of serotonin and the FLSQ results.

CONCLUSIONS

Individuals with DFD diagnosis showed poorer sleep quality, which is likely independent of sex and OSA diagnosis, and negatively correlated with salivary levels of serotonin.

Two-dimensional facial photography for assessment of craniofacial morphology in sleep breathing disorders: a systematic review

PURPOSE

Craniofacial morphology is integral to Sleep Breathing Disorders (SBD), particularly Obstructive Sleep Apnea (OSA), informing treatment strategies. This review assesses the utility of two-dimensional (2D) photogrammetry in evaluating these metrics among OSA patients.

METHODS

Following PRISMA guidelines, a systematic review was conducted. PubMed, Embase, and Lilacs databases were systematically searched for studies utilizing 2D photography in SBD. Findings were narratively synthesized.

RESULTS

Thirteen studies involving 2,328 patients were included. Significant correlations were found between craniofacial measurements-specifically neck parameters and facial width-and OSA severity, even after BMI adjustment. Ethnic disparities in craniofacial morphology were observed, with photogrammetry effective in predicting OSA in Caucasians and Asians, though data for other ethnicities were limited. Pediatric studies suggest the potential of craniofacial measurements as predictors of childhood OSA, with certain caveats.

CONCLUSION

2D photogrammetry emerges as a practical and non-invasive tool correlating with OSA severity across diverse populations. However, further validation in various ethnic cohorts is essential to enhance the generalizability of these findings.

OSA pathophysiology: a contemporary update

Defined as an elevated frequency of obstructive respiratory events in sleep, obstructive sleep apnoea (OSA) is driven by a combination of four pathophysiologic mechanisms: elevated upper airway collapsibility, unstable ventilatory control, impaired upper airway dilator muscle responsiveness and decreased arousal threshold. Established therapies such as continuous positive airway pressure (CPAP) and oral appliance therapy (OAT) work chiefly through targeting elevated collapsibility, which affects the majority of OSA patients. However, many patients respond poorly or do not tolerate these 'anatomic' therapies. The emerging field of 'precision sleep medicine' seeks to determine if novel treatment approaches specifically targeting the other, 'non-anatomic' mechanisms will improve treatment efficacy and acceptance. In this review, we consider the concepts underlying each pathophysiologic mechanism, the predisposing factors, and the potential implications for established and future OSA treatments.

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.

Predicting obstructive sleep apnea hypopnea syndrome using three-dimensional optical devices: A systematic review

Purpose

As a global health concern, the diagnosis of obstructive sleep apnea hypopnea syndrome (OSAHS), characterized by partial reductions and complete pauses in ventilation, has garnered significant scientific and public attention. With the advancement of digital technology, the utilization of three-dimensional (3D) optical devices demonstrates unparalleled potential in diagnosing OSAHS. This study aimed to review the current literature to assess the accuracy of 3D optical devices in identifying the prevalence and severity of OSAHS.

Methods

A systematic literature search was conducted in the Web of Science, Scopus, PubMed/MEDLINE, and Cochrane Library databases for English studies published up to April 2024. Peer-reviewed researches assessing the diagnostic utility of 3D optical devices for OSAHS were included. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) guideline was employed to appraise the risk of bias.

Results

The search yielded 3216 results, with 10 articles meeting the inclusion criteria for this study. Selected studies utilized structured light scanners, stereophotogrammetry, and red, green, blue-depth (RGB-D) cameras. Stereophotogrammetry-based 3D optical devices exhibited promising potential in OSAHS prediction.

Conclusions

The utilization of 3D optical devices holds considerable promise for OSAHS diagnosis, offering potential improvements in accuracy, cost reduction, and time efficiency. However, further clinical data are essential to assist clinicians in the early detection of OSAHS using 3D optical devices.

Anthropometric 3D evaluation of the face in patients with sleep related breathing disorders

PURPOSE

To evaluate craniofacial measurements on 3D-stereophotogrammetry and see if particular measurements are more typical in obstructive sleep apnea (OSA) and have a correlation with its severity.

METHODS

Subjects included were adults undergoing a diagnostic polysomnography. Age, BMI, neck, abdominal and hip circumference (cm) were recorded. 3D-stereophotogrammetry was performed and landmarks were placed on the 3D-image. Different linear, angular and volume measurements were performed to gauge facial and neck anatomy. The relationship between these measurements and the severity of OSA, based on the obstructive apnea/hypopnea index (OAHI, events/h), was assessed by multiple linear regression, and adjusted for BMI and sex.

RESULTS

Of 91 subjects included (61 male), mean age was 46 ± 12 years, BMI 30.1 ± 6.5 kg/m2, OAHI 19.3 ± 18.8/h. BMI was higher (p = 0.0145) in females (32.9 ± 7.7) than in males (28.6 ± 5.3). This was also true for hip circumference (118 ± 15 vs 107 ± 10, p = 0.0006), while the neck circumference was higher (p < 0.0001) in males (41 ± 4 vs 37 ± 4). The following parameters could predict the logOAHI (r2-adjusted = 0.51): sex (p < 0.0001), BMI (p = 0.0116), neck-depth/mandibular-length (p = 0.0002), mandibular-width angle (p = 0.0118), neck-depth euclidean distance/surface distance (E/S) (p = 0.0001) and the interaction terms between sex and neck-depth/mandibular-length (p = 0.0034), sex and neck-depth E/S (p = 0.0276) and BMI and neck-depth E/S (p = 0.0118). The interaction between sex and neck-depth/mandibular-length showed a steeper linear course in females. This is also true for the interaction term BMI with neck-depth E/S in patients with a higher BMI. With a same neck-depth ratio, the OAHI is larger in men.

CONCLUSION

Measurements involving the width of the face and addressing the soft tissue in the upper neck were found to have a significant relation with OSA severity. We found remarkable differences between non-obese/obese subjects and between males and females.

Deep learning technique to detect craniofacial anatomical abnormalities concentrated on middle and anterior of face in patients with sleep apnea

OBJECTIVES

The aim of this study is to propose a deep learning-based model using craniofacial photographs for automatic obstructive sleep apnea (OSA) detection and to perform design explainability tests to investigate important craniofacial regions as well as the reliability of the method.

METHODS

Five hundred and thirty participants with suspected OSA are subjected to polysomnography. Front and profile craniofacial photographs are captured and randomly segregated into training, validation, and test sets for model development and evaluation. Photographic occlusion tests and visual observations are performed to determine regions at risk of OSA. The number of positive regions in each participant is identified and their associations with OSA is assessed.

RESULTS

The model using craniofacial photographs alone yields an accuracy of 0.884 and an area under the receiver operating characteristic curve of 0.881 (95% confidence interval, 0.839-0.922). Using the cutoff point with the maximum sum of sensitivity and specificity, the model exhibits a sensitivity of 0.905 and a specificity of 0.941. The bilateral eyes, nose, mouth and chin, pre-auricular area, and ears contribute the most to disease detection. When photographs that increase the weights of these regions are used, the performance of the model improved. Additionally, different severities of OSA become more prevalent as the number of positive craniofacial regions increases.

CONCLUSIONS

The results suggest that the deep learning-based model can extract meaningful features that are primarily concentrated in the middle and anterior regions of the face.

Facial Contour Features Measured on CT Reflects Upper Airway Morphology in Patients With OSA

OBJECTIVE

To determine facial contour features, measured on computed tomography (CT), related to upper airway morphology in patients with obstructive sleep apnea (OSA); certain phenotype of facial abnormalities implying restriction of craniofacial skeleton and adipose tissue nimiety has predicted the value of the severity of OSA.

MATERIALS AND METHOD

Sixty-four male patients with OSA [apnea-hypopnea index (AHI) ≥10/h] who had upper airway CT were randomly selected to quantitatively measure indicators of facial contour and upper airway structures. Pearson correlation analyses were performed. Partial correlation procedure was used to examine correlations while controlling body mass index (BMI).

RESULTS

Upper airway anatomy can nearly all be reflected in the face, except retroglossal airway. Upper face width can be measured to assess the overall skeletal structures of the airway. Lower face width can be used to represent how much adipose tissue deposited. Hard palate, retropalatal, and hypopharyngeal airways have corresponding face indicators respectively. Midface width is a better predictor of AHI severity and minimum blood oxygen even than neck circumference because it contains the most anatomical information about the airway, including RP airway condition, soft palate length, tongue volume, etc. These correlations persisted even after correction for BMI.

CONCLUSIONS

All anatomical features of the upper airway except retroglossal airway can be reflected in the face, and midface width is the best predictor of AHI severity and minimum blood oxygen, even better than neck circumference and BMI.

Multi-stage Unet segmentation and automatic measurement of pharyngeal airway based on lateral cephalograms

OBJECTIVES

Orthodontic treatment profoundly impact the pharyngeal airway (PA) of patients. Airway examination is an integral part of daily orthodontic diagnosis, and lateral cephalograms (LC) are reliable to reveal PA structures. This study attempted to develop a simple method to help clinicians make a preliminary judgement of patients' PA conditions and assess the impact of orthodontic treatment on their airways.

METHODS

LCs of 764 patients were used to train a multistage unit segmentation model. Another 130 images were used to validate the model and more 130 images were used to test the model.

RESULTS

Unet was used as the backbone, with a mean dice value of 0.8180, precision of 0.8393, and recall of 0.8188. Furthermore, we identified seven key points and measured related indices. The length of the line separating the nasopharynx and oropharynx and the line separating the oropharynx and hypopharynx were manually measured thrice and the average values was compared. The intraclass correlation coefficient (ICC) for the two lines was 0.599 and 0.855. Then, we performed a single linear regression analysis, which indicated a strong correlation between the predictions and measurements for the two lines.

CONCLUSIONS

This method is reliable for segmenting three regions (nasopharynx, oropharynx, and hypopharynx) of the PA and calculating related indices. However, the predictions obtained from this model still have errors, and it is necessary for clinical practitioners to assess and adjust the predictions.

CLINICAL SIGNIFICANCE

Our model can help orthodontists formulate personalised treatment plans and evaluate the risk of airway stenosis during orthodontic treatment. This method may mark the beginning of a new and simpler approach for PA obstruction detection, specifically tailored to orthodontic patients.

Association of Backscattered Ultrasonographic Imaging of the Tongue With Severity of Obstructive Sleep Apnea in Adults

Importance

Determining interventions to manage obstructive sleep apnea (OSA) depends on clinical examination, polysomnography (PSG) results, and imaging analysis. There remains the need of a noninvasive and cost-effective way to correlate relevant upper airway anatomy with severity of OSA to direct treatment and optimize outcome.

Objective

To determine whether backscattered ultrasonographic imaging (BUI) analysis of the tongue is associated with severity of OSA in adults.

Design, Setting, and Participants

In this prospective, single-center, diagnostic study of a consecutive series of patients (aged ≥18 years) at a sleep surgery clinic, the 89 included patients had a PSG within 3 years at the time of ultrasonography and BUI analysis between July 2020 and March 2022. Patients were excluded if body mass index had changed more than 10% since time of PSG. A standardized submental ultrasonographic scan with laser alignment was used with B-mode and BUI analysis applied to the tongue. The B-mode and BUI intensity were associated with the apnea-hypopnea index (AHI), a measure of severity of apnea from normal (no OSA) to severe OSA.

Exposures

Ultrasonography and PSG.

Main Outcomes and Measures

The main outcomes were BUI parameters and their association with AHI value.

Results

Eighty-nine patients were included between July 2020 and March 2022. A total of 70 (78.7%) male patients were included; and distribution by race and ethnicity was 46 (52%) White participants, 22 (25%) Asian participants, and 2 (2%) African American participants, and 19 (21%) others. Median (IQR) age was 37.0 (29.0-48.3) years; median (IQR) BMI was 25.3 (23.2-29.8); and median (IQR) AHI was 11.1 (5.6-23.1) events per hour. At the middle to posterior tongue region, the 4 OSA severity levels explained a significant portion of the BUI variance (η2 = 0.153-0.236), and a significant difference in BUI values was found between the subgroups with AHI values of less than 15 (no OSA and mild OSA) and greater than or equal to 15 (moderate OSA and severe OSA) events per hour. The echo intensity showed no significant differences. The BUI values showed a positive association with AHI, with a Spearman correlation coefficient of up to 0.43. Higher BUI values remained associated with higher AHI after correction for the covariates of BMI and age.

Conclusions and Relevance

In this prospective diagnostic study, standardized BUI analysis of the tongue was associated with OSA severity. With the practicality of ultrasonography, this analysis is pivotal in connecting anatomy with physiology in treatment planning for patients with OSA.

Prediction of obstructive sleep apnea using deep learning in 3D craniofacial reconstruction

Background

Obstructive sleep apnea (OSA) is a common sleep disorder. However, current diagnostic methods are labor-intensive and require professionally trained personnel. We aimed to develop a deep learning model using upper airway computed tomography (CT) to predict OSA and to warn the medical technician if a patient has OSA while the patient is undergoing any head and neck CT scan, even for other diseases.

Methods

A total of 219 patients with OSA [apnea-hypopnea index (AHI) ≥10/h] and 81 controls (AHI <10/h) were enrolled. We reconstructed each patient's CT into 3 types (skeletal structures, external skin structures, and airway structures) and captured reconstructed models in 6 directions (front, back, top, bottom, left profile, and right profile). The 6 images from each patient were imported into the ResNet-18 network to extract features and output the probability of OSA using two fusion methods: Add and Concat. Five-fold cross-validation was used to reduce bias. Finally, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated.

Results

All 18 views with Add as the feature fusion performed better than did the other reconstruction and fusion methods. This gave the best performance for this prediction method with an AUC of 0.882.

Conclusions

We present a model for predicting OSA using upper airway CT and deep learning. The model has satisfactory performance and enables CT to accurately identify patients with moderate to severe OSA.

Classification of facial phenotypes in Asian patients with obstructive sleep apnea

BACKGROUD

The facial phenotypes of Asian obstructive sleep apnea (OSA) patients remain unclear.

OBJECTIVES

(1) To describe the facial features of OSA patients. (2) To develop a model based on facial contour indicators to predict OSA. (3) To classify the facial phenotypes of Asian OSA patients.

MATERIALS AND METHODS

110 patients with OSA (apnea-hypopnea index [AHI] ≥ 10/h) and 50 controls (AHI< 10/h) were selected to measure facial contour indicators. Indicators were compared between OSA patients and the control group. We used multivariable linear regression analysis to predict OSA severity and K-means cluster analysis to classify OSA patients into different phenotypes.

RESULTS

We built a model to predict OSA which explained 49.1% of its variance and classified OSA patients into four categories. Cluster 1 (Skeletal type) had the narrowest facial width indicators with narrowing of the retroglossal airway. Cluster 2 (Obese type) had the widest face, and narrowest hard palate, retropalatal, and hypopharyngeal airways. Cluster 3 (Nose type) had the narrowest nasal cavity. Cluster 4 (Long type) had the longest airway length.

CONCLUSIONS AND SIGNIFICANCE

Patients with OSA were classified into four categories, each of which identified different anatomic risk factors that can be used to select the treatment.

Obstructive sleep apnea

Obstructive sleep apnea (OSA) is a disease that results from loss of upper airway muscle tone leading to upper airway collapse during sleep in anatomically susceptible persons, leading to recurrent periods of hypoventilation, hypoxia, and arousals from sleep. Significant clinical consequences of the disorder cover a wide spectrum and include daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic dysfunction, respiratory failure, and pulmonary hypertension. With escalating rates of obesity a major risk factor for OSA, the public health burden from OSA and its sequalae are expected to increase, as well. In this chapter, we review the mechanisms responsible for the development of OSA and associated neurocognitive and cardiometabolic comorbidities. Emphasis is placed on the neural control of the striated muscles that control the pharyngeal passages, especially regulation of hypoglossal motoneuron activity throughout the sleep/wake cycle, the neurocognitive complications of OSA, and the therapeutic options available to treat OSA including recent pharmacotherapeutic developments.

Predicting sleep apnea from three-dimensional face photography

STUDY OBJECTIVES

Craniofacial anatomy is recognized as an important predisposing factor in the pathogenesis of obstructive sleep apnea (OSA). This study used three-dimensional (3D) facial surface analysis of linear and geodesic (shortest line between points over a curved surface) distances to determine the combination of measurements that best predicts presence and severity of OSA.

METHODS

3D face photographs were obtained in 100 adults without OSA (apnea-hypopnea index [AHI] < 5 events/h), 100 with mild OSA (AHI 5 to < 15 events/h), 100 with moderate OSA (AHI 15 to < 30 events/h), and 100 with severe OSA (AHI ≥ 30 events/h). Measurements of linear distances and angles, and geodesic distances were obtained between 24 anatomical landmarks from the 3D photographs. The accuracy with which different combinations of measurements could classify an individual as having OSA or not was assessed using linear discriminant analyses and receiver operating characteristic analyses. These analyses were repeated using different AHI thresholds to define presence of OSA.

RESULTS

Relative to linear measurements, geodesic measurements of craniofacial anatomy improved the ability to identify individuals with and without OSA (classification accuracy 86% and 89% respectively, P < .01). A maximum classification accuracy of 91% was achieved when linear and geodesic measurements were combined into a single predictive algorithm. Accuracy decreased when using AHI thresholds ≥ 10 events/h and ≥ 15 events/h to define OSA although greatest accuracy was always achieved using a combination of linear and geodesic distances.

CONCLUSIONS

This study suggests that 3D photographs of the face have predictive value for OSA and that geodesic measurements enhance this capacity.

Estimation of Apnea-Hypopnea Index using Deep Learning on 3D Craniofacial Scans

Obstructive sleep apnea (OSA) is characterized by decreased breathing events that occur through the night, with severity reported as the apnea-hypopnea index (AHI), which is associated with certain craniofacial features. In this study, we used data from 1366 patients collected as part of Stanford Technology Analytics and Genomics in Sleep (STAGES) across 11 US and Canadian sleep clinics and analyzed 3D craniofacial scans with the goal of predicting AHI, as measured using gold standard nocturnal polysomnography (PSG). First, the algorithm detects pre-specified landmarks on mesh objects and aligns scans in 3D space. Subsequently, 2D images and depth maps are generated by rendering and rotating scans by 45-degree increments. Resulting images were stacked as channels and used as input to multi-view convolutional neural networks, which were trained and validated in a supervised manner to predict AHI values derived from PSGs. The proposed model achieved a mean absolute error of 11.38 events/hour, a Pearson correlation coefficient of 0.4, and accuracy for predicting OSA of 67% using 10-fold cross-validation. The model improved further by adding patient demographics and variables from questionnaires. We also show that the model performed at the level of three sleep medicine specialists, who used clinical experience to predict AHI based on 3D scan displays. Finally, we created topographic displays of the most important facial features used by the model to predict AHI, showing importance of the neck and chin area. The proposed algorithm has potential to serve as an inexpensive and efficient screening tool for individuals with suspected OSA.

Evaluation and Management of Adults with Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is a common and underdiagnosed medical condition characterized by recurrent sleep-dependent pauses and reductions in airflow. While a narrow, collapsible oropharynx plays a central role in the pathophysiology of OSAS, there are other equally important nonanatomic factors including sleep-stage dependent muscle tone, arousal threshold, and loop gain that drive obstructive apneas and hypopneas. Through mechanisms of intermittent hypoxemia, arousal-related sleep fragmentation, and intrathoracic pressure changes, OSAS impacts multiple organ systems. Risk factors for OSAS include obesity, male sex, age, specific craniofacial features, and ethnicity. The prevalence of OSAS is rising due to increasing obesity rates and improved sensitivity in the tools used for diagnosis. Validated questionnaires have an important but limited role in the identification of patients that would benefit from formal testing for OSA. While an in-laboratory polysomnography remains the gold standard for diagnosis, the widespread availability and accuracy of home sleep apnea testing modalities increase access and ease of OSAS diagnosis for many patients. In adults, the most common treatment involves the application of positive airway pressure (PAP), but compliance continues to be a challenge. Alternative treatments including mandibular advancement device, hypoglossal nerve stimulator, positional therapies, and surgical options coupled with weight loss and exercise offer possibilities of an individualized personal approach to OSAS. Treatment of symptomatic patients with OSAS has been found to be beneficial with regard to sleep-related quality of life, sleepiness, and motor vehicle accidents. The benefit of treating asymptomatic OSA patients, particularly with regard to cardiovascular outcomes, is controversial and more data are needed.

The presence of insomnia and depression contributes to the acceptance of an initial treatment trial of continuous positive airway pressure therapy in patients with obstructive sleep apnea

The presence of comorbid insomnia and sleep apnea (COMISA) reduces the initial acceptance of continuous positive airway pressure (CPAP) therapy in 39-58% of patients with obstructive sleep apnea (OSA). Depressive disorders are reported in 5 to 63% of patients with OSA. Here we studied the co-occurrence of depression and insomnia in OSA patients and its impact on treatment acceptance in a real-life controlled trial.

METHODS

In this prospective, uncontrolled study, participants were recruited from January to December 2018, among adult patients who visited our sleep lab. Participants underwent polysomnography study and completed the Epworth Sleepiness Scale (ESS), Athens Insomnia Scale (AIS), and Zung Depression Rating Scale (ZDRS). All subjects were categorized into 8 groups: no OSA/no depression (apnea-hypopnea index [AHI] < 5/h, n = 34), mild OSA/no depression (AHI = 5-14/h, n = 22), moderate OSA/no depression (AHI = 15-29/h, n = 44), severe OSA/no depression (AHI ≥ 30/h, n = 45), no OSA/mild depression (AHI < 5/h, n = 31), mild OSA/mild depression (AHI = 5-14/h, n = 24), moderate OSA/mild depression (AHI = 15-29/h, n = 31), and severe OSA/mild depression (AHI ≥ 30/h, n = 40).

RESULTS

Over the one-year period, 272 participants (200 men, mean age 52.9 ± 13.0 years, BMI 33.6 ± 7.2 kg/m²) were enrolled. When the above 8 groups were subcategorized into the presence or absence of insomnia, we found no differences in CPAP trial acceptance between subgroups except in patients from the mild depression/severe OSA/insomnia subgroup who denied CPAP therapy more frequently (chi-squared test p = 0.016). We found, with a moderate efficiency indicated by the ROC curve, that patients with AHI > 15/h, AIS ≥ 11, and ZDRS > 44 were more likely to refuse an initial trial of CPAP treatment because of COMISA and depression (ROC curve area = 0.710, p = 0.049).

CONCLUSION

This study demonstrates that it is important to recognize a depressive mood disorder in patients with moderate/severe OSA and COMISA as the coexistence of these comorbidities impairs the rate of initial acceptance of CPAP treatment. Additionally, our study suggests the cut-off values from the AIS and ZDRS questionnaires to help lead clinicians to an early diagnostic evaluation of COMISA patients for the presence of depressive mood disorder.

Imaging of sleep-disordered breathing in adults

Sleep-disordered breathing (SDB) is a term that includes several chronic conditions in which partial or complete cessation of breathing occurs multiple times throughout the night. Central sleep apnoea (CSA) is uncommon and defined by the episodic cessation of airflow without respiratory effort. Lesions involving the respiratory centre in the brainstem or the origin of the phrenic nerve from the mid-cervical cord are the commonest structural causes of CSA; magnetic resonance imaging (MRI) will demonstrate the lesion and frequently suggest the likely aetiology. In contrast, obstructive sleep apnoea (OSA) is defined as upper airway obstruction despite ongoing respiratory effort. Repetitive episodes of narrowing or closure of the upper airway are the predominant cause leading to snoring and OSA, respectively. OSA affects 33-40% of the adult population and is associated with multiple adverse health consequences, including a significantly increased risk of serious morbidity and mortality. The incidence is increasing proportionally to the worldwide rise in obesity. Imaging, performed primarily without the involvement of radiologists, has been integral to understanding the anatomical basis of SDB and especially OSA. This article will review the pathophysiology, imaging findings, and sequelae of these common conditions. The role of imaging both in suggesting the incidental diagnoses of SDB and in the investigation of these conditions when the diagnosis is suspected or has been established are also discussed.

Defining Extreme Phenotypes of OSA Across International Sleep Centers

BACKGROUND

Extreme phenotypes of OSA have not been systematically defined.

RESEARCH QUESTION

This study developed objective definitions of extreme phenotypes of OSA by using a multivariate approach. The utility of these definitions for identifying characteristics that confer predisposition toward or protection against OSA is shown in a new prospective sample.

STUDY DESIGN AND METHODS

In a large international sample, race-specific liability scores were calculated from a weighted logistic regression that included age, sex, and BMI. Extreme cases were defined as individuals with an apnea-hypopnea index (AHI) ≥ 30 events/hour but low likelihood of OSA based on age, sex, and BMI (liability scores > 90th percentile). Similarly, extreme controls were individuals with an AHI < 5 events/hour but high likelihood of OSA (liability scores < 10th percentile). Definitions were applied to a prospective sample from the Sleep Apnea Global Interdisciplinary Consortium, and differences in photography-based craniofacial and intraoral phenotypes were evaluated.

RESULTS

This study included retrospective data from 81,338 individuals. A total of 4,168 extreme cases and 1,432 extreme controls were identified by using liability scores. Extreme cases were younger (43.1 ± 14.7 years), overweight (28.6 ± 6.8 kg/m²), and predominantly female (71.1%). Extreme controls were older (53.8 ± 14.1 years), obese (34.0 ± 8.1 kg/m²), and predominantly male (65.8%). These objective definitions identified 29 extreme cases and 87 extreme controls among 1,424 Sleep Apnea Global Interdisciplinary Consortium participants with photography-based phenotyping. Comparisons suggest that a greater cervicomental angle increases risk for OSA in the absence of clinical risk factors, and smaller facial widths are protective in the presence of clinical risk factors.

INTERPRETATION

This objective definition can be applied in sleep centers throughout the world to consistently define OSA extreme phenotypes for future studies on genetic, anatomic, and physiologic pathways to OSA.

Influence of tongue volume, oral cavity volume and their ratio on upper airway: A cone beam computed tomography study

Background

Our study aimed to measure the tongue volume (TV), oral cavity volume (OCV), and their ratio (TV/OCV) and correlate with upper airway using cone-beam computed tomography (CBCT).

Method

The volume of oral cavity, tongue and upper airway were obtained by the manual process of segmentation of CBCT data of 15 subjects. The mean age of the sample was 21.86 years (range 15-33 years). Segmentation of the upper airway, tongue and oral cavity was performed manually using Mimics 11.0 (Materialise, Leuven, Belgium) software at different thresholds for air and the tongue. The Hounsfield units (HU) for airway volume of the different facial region ranged from -1024 to -500. For tongue volume, Hounsfield units (HU), ranging from -200 to 200 was calculated.

Results

A significant negative correlation between TV/OCV and oropharynx (r = - 0.51; P = 0.04), TV/OCV and oral cavity airway volume (r = - 0.74; P = 0.002) was found. There was a significant and a positive correlation with TV/OCV and tongue volume (r = 0.65; P = 0.009).

Conclusion

A significant negative correlation established between TV/OCV, oropharynx and oral cavity airway volume. This finding indicates an influence tongue volume, oral cavity volume and their ratio on patency of the oropharynx.

TORS for OSA: a practice, pitfalls and literature review

PURPOSE

Trans-oral robotic surgery (TORS) is increasingly employed in obstructive sleep apnoea (OSA) management. Objective outcomes are generally assessed through polysomnography. Pre-operative magnetic resonance imaging (MRI) can be a useful adjunct in objective upper airway assessment, in particular the tongue base, providing useful information for surgical planning and outcome assessment, though care must be taken in patient positioning during surgery. The purpose of this paper is to identify pitfalls in this process and suggest a protocol for pre-operative MRI scanning in OSA.

DESIGN/METHODOLOGY/APPROACH

This study is a four-patient prospective case-series and literature review. Outcome measures include pre- and post-operative volumetric changes in the pharynx as measured on MRI and apnoea-hypopnea indices (AHI), with cure being OSA resolution or a 50 per cent reduction in AHI.

FINDINGS

All patients achieved AHI reduction and/or OSA cure following TORS, despite a decrease in pharyngeal volume measurements at the tongue base level. This study and others lacked standardisation in the MRI scanning protocol, which resulted in an inability to effectively compare pre- and post-operative scans. Pitfalls were related to variation in head/tongue position, soft-tissue marker usage and assessed area boundary limits.

PRACTICAL IMPLICATIONS

TORS appears to be effective in OSA management. A new protocol for patient positioning and anatomical landmarks is suggested.

ORIGINALITY/VALUE

The findings could provide directly comparable data between scans and may allow correlation between tongue base volumetric changes and AHI through subsequent and historical study meta-analysis.

Sleep Apnea Multilevel Surgery (SAMS) trial protocol: a multicenter randomized clinical trial of upper airway surgery for patients with obstructive sleep apnea who have failed continuous positive airway pressure

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a serious and costly public health problem. The main medical treatment, continuous positive airway pressure, is efficacious when used, but poorly tolerated in up to 50% of patients. Upper airway reconstructive surgery is available when medical treatments fail but randomized trial evidence supporting its use is limited. This protocol details a randomized controlled trial designed to assess the clinical effectiveness, safety, and cost-effectiveness of a multilevel upper airway surgical procedure for OSA.

METHODS

A prospective, parallel-group, open label, randomized, controlled, multicenter clinical trial in adults with moderate or severe OSA who have failed or refused medical therapies. Six clinical sites in Australia randomly allocated participants in a 1:1 ratio to receive either an upper airway surgical procedure consisting of a modified uvulopalatopharyngoplasty and minimally invasive tongue volume reduction, or to continue with ongoing medical management, and followed them for 6 months.

RESULTS

Primary outcomes: difference between groups in baseline-adjusted 6 month OSA severity (apnea-hypopnea index) and subjective sleepiness (Epworth Sleepiness Scale). Secondary outcomes: other OSA symptoms (e.g. snoring and objective sleepiness), other polysomnography parameters (e.g. arousal index and 4% oxygen desaturation index), quality of life, 24 hr ambulatory blood pressure, adverse events, and adherence to ongoing medical therapies (medical group).

CONCLUSIONS

The Sleep Apnea Multilevel Surgery (SAMS) trial is of global public health importance for testing the effectiveness and safety of a multilevel surgical procedure for patients with OSA who have failed medical treatment.

CLINICAL TRIAL REGISTRATION

Multilevel airway surgery in patients with moderate-severe Obstructive Sleep Apnea (OSA) who have failed medical management to assess change in OSA events and daytime sleepiness. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366019&isReview=true Australian New Zealand Clinical Trials Registry ACTRN12614000338662, prospectively registered on 31 March 2014.

From CPAP to tailored therapy for obstructive sleep Apnoea

Obstructive Sleep Apnoea (OSA) is a common sleep disorder that is associated with daytime symptoms and a range of comorbidity and mortality. Continuous Positive Airway Pressure (CPAP) therapy is highly efficacious at preventing OSA when in use and has long been the standard treatment for newly diagnosed patients. However, CPAP therapy has well recognised limitations in real world effectiveness due to issues with patient acceptance and suboptimal usage. There is a clear need to enhance OSA treatment strategies and options. Although there are a range of alternative treatments (e.g. weight loss, oral appliances, positional devices, surgery, and emerging therapies such as sedatives and oxygen), generally there are individual differences in efficacy and often OSA will not be completely eliminated. There is increasing recognition that OSA is a heterogeneous disorder in terms of risk factors, clinical presentation, pathophysiology and comorbidity. Better characterisation of OSA heterogeneity will enable tailored approaches to therapy to ensure treatment effectiveness. Tools to elucidate individual anatomical and pathophysiological phenotypes in clinical practice are receiving attention. Additionally, recognising patient preferences, treatment enhancement strategies and broader assessment of treatment effectiveness are part of tailoring therapy at the individual level. This review provides a narrative of current treatment approaches and limitations and the future potential for individual tailoring to enhance treatment effectiveness.

Insomnia symptoms combined with nocturnal hypoxia associate with cardiovascular comorbidity in the European sleep apnea cohort (ESADA)

Purpose

The aim of the current study was to further investigate the concept of previously reported high occurrence of comorbidities in obstructive sleep patients (OSA) with insomnia-like symptoms. We hypothesized that this finding at least partly is mediated by nocturnal hypoxia. Moreover, we speculated that the spectrum of the clinical OSA phenotypes differs between European geographical regions.

Methods

Cohort of the European Sleep Apnea Database (n = 17,325; 29.9% females) was divided into five subcohorts according to geographical region (North, East, South, West, Central) and further into four clinical presentation phenotypes based on daytime symptoms (EDS) and characteristics suggestive of insomnia.

Results

The insomnia phenotype (alone or together with EDS) dominated in all European regions. Isolated insomnia, however, was less common in the West. Insomnia phenotype was associated with the highest proportion of cardiovascular comorbidity (51.7% in the insomnia vs. 43.9% in the EDS type). Measures of nocturnal hypoxemia were independently associated with cardiovascular comorbidity in phenotypes with insomnia-like symptoms. The burden of comorbidities was high across all geographical regions and clinical phenotypes. Regional differences were clinically relevant for age (48 vs. 54 years), BMI (29 vs. 34 kg/m²), and ODI (15 vs. 32/h).

Conclusion

High prevalence of particularly cardiovascular comorbidity among patients with insomnia-like symptoms was linked to nocturnal hypoxemia. Considerable differences in clinical presentation were found among OSA patients across Europe. Our data underline that physicians should ask their patients with suspected OSA also for insomnia symptoms. It remains to be explored if a reduction of nocturnal hypoxemia predicts the improvement of insomnia symptoms.

Electronic supplementary material

The online version of this article (10.1007/s11325-018-1757-9) contains supplementary material, which is available to authorized users.

Choosing the right mask for your Asian patient with sleep apnoea: A randomized, crossover trial of CPAP interfaces

BACKGROUND AND OBJECTIVE

A major challenge with the treatment of obstructive sleep apnoea (OSA) is adherence to continuous positive airway pressure (CPAP) therapy. Mask tolerability is an important determinant of adherence, however evidence to guide selection of mask interfaces is lacking.

METHODS

We conducted a randomized crossover trial of mask interfaces in CPAP therapy for moderate-to-severe OSA to assess adherence and efficacy of CPAP therapy with nasal mask, nasal pillow and oronasal masks. Demographic data, Nasal Obstruction Symptom Evaluation (NOSE) scores and craniofacial measurements were also analysed for associations with adherence with oronasal masks.

RESULTS

Eighty-five patients were included in the study (mean ± SD age: 46 ± 12 years; body mass index: 29.9 ± 5.6 kg/m² ; apnoea-hypopnoea index (AHI): 53.6 ± 24.0 events/h). Patients had better adherence with nasal masks (average night use: 3.96 ± 2.26 h/night) compared to oronasal masks (3.26 ± 2.18 h/night, P < 0.001) and nasal pillows (3.48 ± 2.20 h/night, P = 0.007). Residual AHI was higher with oronasal masks (7.2 ± 5.2) compared to nasal masks (4.0 ± 4.2, P < 0.001) and nasal pillows (4.1 ± 3.3, P < 0.001). Twenty-two (25.9%) patients had the best adherence with oronasal masks (4.22 ± 2.14 vs 2.93 ± 2.12 h/night, P = 0.016). These patients had lower NOSE scores (15 (0-35) vs 40 (10-55), P = 0.024) and larger menton-labrale inferioris/biocular width ratios (31 ± 3% vs 28 ± 4%, P = 0.019).

CONCLUSION

Nasal masks are the preferred interface during CPAP initiation. Patients with less nasal obstruction and a proportionally increased chin-lower lip distance to mid-face width may have better CPAP adherence with an oronasal mask interface.

High Risk Characteristics for Recurrent Cardiovascular Events among Patients with Obstructive Sleep Apnoea in the SAVE Study

BACKGROUND

Obstructive sleep apnoea (OSA) is a common comorbidity in patients with cardiovascular (CV) disease. We aimed to identify specific OSA clinical phenotypes relating to risks of serious CV events and response to continuous positive airway pressure (CPAP) treatment.

METHODS

Post-hoc analyses of the Sleep Apnea Cardiovascular Endpoints (SAVE) study in participants with moderate-to-severe OSA and coronary artery disease (CAD) and/or cerebrovascular disease (CeVD) randomised to CPAP plus usual care or usual care alone. Latent class analysis (LCA) was used to identify OSA clinical phenotypes among 2649 (out of 2687 total) patients with complete data on 19 patient-centered variables, supported by Bayesian information criteria and clinical interpretability. Cox regression models were used to evaluate risks of composite cardiac and stroke outcome events in phenotype groups. Preferential response to CPAP treatment was evaluated using interaction terms as well as the Chi-square test.

FINDINGS

LCA identified four OSA clinical phenotypes: CAD alone and with diabetes mellitus (CAD + DM), and CeVD alone and with DM (CeVD + DM), in 39%, 15%, 37% and 9% of participants, respectively. The rates of composite CV events were the highest in CAD + DM phenotype (HR 2.08, 95% CI 1.57-2.76) and for stroke were highest in CeVD + DM phenotype (HR 6.84, 95% CI 3.77-12.42). Adherence to CPAP treatment (nil or < 4 h vs ≥ 4 h in the first two years of the study) was shown to influence the risk of composite CV outcome in the phenotypes (P-interaction = 0.04); CPAP adherent patients of the CeVD + DM phenotype had the lowest risk of CV outcome (P = 0.02).

INTERPRETATION

High risk clinical phenotypes were identified in relation to CV events and response to CPAP treatment, which may allow improved targeting of therapies in OSA patients.

FUNDING

The National Health and Medical Research Council (NHMRC) of Australia, Fisher & Paykel Healthcare, and ResMed.

Craniofacial Phenotyping in Chinese and Caucasian Patients With Sleep Apnea: Influence of Ethnicity and Sex

STUDY OBJECTIVES

Craniofacial abnormalities are a risk factor for obstructive sleep apnea (OSA). We have previously shown that phenotypic information derived from craniofacial photographs predict OSA in sleep clinic populations. However, there are likely ethnic and sex differences in craniofacial phenotypes related to OSA. We aimed to assess the use of craniofacial photography to identify interactions between OSA, ethnicity, and sex in craniofacial phenotype.

METHODS

Frontal and profile craniofacial photographs were analyzed from two sleep clinic populations of different ethnicity (Hong Kong Chinese, Australian Caucasians). OSA was defined as apnea-hypopnea index (AHI) > 10 events/h. Ten craniofacial measurements (three angles relating to jaw position and seven ratios describing proportions of the face) were examined for interactions between OSA status and sex or ethnicity) using factorial analysis of variance.

RESULTS

A total of 363 subjects (25% female) were included (n = 200 Chinese, n = 163 Caucasian), of which 33% were controls. There were two-way interactions for OSA with both sex (mandibular plane angle [F = 7.0, P = .009], face / eye width ratio [F = 4.7, P = .032], maxillary / mandibular volume ratio [F = 9.2, P = .003]) and ethnicity (face / nose width ratio [F = 4.0, P = .045], mandibular width / length ratio [F = 5.1, P = .024], maxillary / mandibular volume ratio [F = 11.0, P = .001]).

CONCLUSIONS

We provide evidence of ethnic and sex differences in facial phenotype related to OSA. Furthermore, we demonstrate that craniofacial photography can be used as a phenotypic tool to assess these differences and allow investigation of OSA phenotypes in large samples. This has relevance to personalizing OSA recognition strategies across different populations.

Rationale and Design of the Turkish Sleep Apnea Database - TURKAPNE: A National, Multicenter, Observational, Prospective Cohort Study

OBJECTIVES

The primary aim of The Turkish Sleep Apnea Database (TURKAPNE) study is to generate a cross-sectional nationwide database for defining the clinical and polysomnographic characteristics of the patients with obstructive sleep apnea (OSA) in Turkey.

MATERIALS AND METHODS

In this ongoing project, all consecutive adults with suspected OSA are recruited from the sleep centers of the university and research hospitals in Turkey. Information on anthropometric data, educational status, driving license, smoking habits, alcohol use, comorbidities, drug use, questionnaires, polysomnographic, and/or cardiorespiratory polygraphic findings are recorded in a systematized Web-based report form. Blood glucose, lipids and other biochemical markers, lung function, and echocardiography measurements are optionally included. Follow-up data regarding treatment modality and compliance is assessed. Cross-sectional and longitudinal associations between OSA phenotypes and metabolic, pulmonary, and cardiovascular comorbidities as well as traffic accidents, and the impact of treatment will be further explored. We target a total sample of 10,000 participants.

RESULTS

The study was registered with ClinicalTrials.gov (NCT02784977) in May 2016 and the first patient was recruited in October 2017. A total of 1911 participants from 19 centers have been enrolled in the study by May 31, 2018.

CONCLUSION

The TURKAPNE study will contribute to a better understanding of the health-related burden of OSA phenotypes and its association with the comorbidities and adverse outcomes, including traffic accidents in Turkey. The results may also contribute to a more personalized approach and better management of varying OSA phenotypes with concomitant disorders.

Evaluation of tongue volume and oral cavity capacity using cone-beam computed tomography

The aims of this study were to reveal the usefulness of a newly developed method for measuring tongue volume (TV) and oral cavity capacity (OCC) and to assess the relationship between them. The tongue was coated with a contrast agent, and the TV and OCC were determined using cone-beam computed tomography (CBCT). We enrolled 20 adults who were scheduled to undergo CBCT to evaluate the relationship of the third molar roots to the alveolar nerve before molar extraction. Each participant’s tongue was coated with a contrast agent, and CBCT of the tongue and oral cavity was performed. Using computer software, we evaluated reconstructed 3D images of the TV, oral cavity proper volume (OCPV), and OCC. The mean TV was 47.07 ± 7.08 cm³. The mean OCPV and OCC were 4.40 ± 2.78 cm³ and 51.47 ± 6.46 cm³, respectively. There was a significant correlation between TV and OCC (r = 0.920; p < 0.01) but not between TV and OCPV. The mean TV/OCC ratio was 91 ± 5%. The proposed method produced CBCT images that enabled effective measurement of TV and OCC. This simple method of measuring TV and OCC will be useful in the diagnosis on the tongues with abnormal size.

Three-dimensional photography for the evaluation of facial profiles in obstructive sleep apnoea

BACKGROUND AND OBJECTIVE

Craniofacial structure is an important determinant of obstructive sleep apnoea (OSA) syndrome risk. Three-dimensional stereo-photogrammetry (3dMD) is a novel technique which allows quantification of the craniofacial profile. This study compares the facial images of OSA patients captured by 3dMD to three-dimensional computed tomography (3-D CT) and two-dimensional (2-D) digital photogrammetry. Measurements were correlated with indices of OSA severity.

METHODS

Thirty-eight patients diagnosed with OSA were included, and digital photogrammetry, 3dMD and 3-D CT were performed. Distances, areas, angles and volumes from the images captured by three methods were analysed.

RESULTS

Almost all measurements captured by 3dMD showed strong agreement with 3-D CT measurements. Results from 2-D digital photogrammetry showed poor agreement with 3-D CT. Mandibular width, neck perimeter size and maxillary volume measurements correlated well with the severity of OSA using all three imaging methods. Mandibular length, facial width, binocular width, neck width, cranial base triangle area, cranial base area 1 and middle cranial fossa volume correlated well with OSA severity using 3dMD and 3-D CT, but not with 2-D digital photogrammetry.

CONCLUSION

3dMD provided accurate craniofacial measurements of OSA patients, which were highly concordant with those obtained by CT, while avoiding the radiation associated with CT.

Obstructive Sleep Apnea in Women: Study of Speech and Craniofacial Characteristics

Background

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by frequent cessation of breathing lasting 10 seconds or longer. The diagnosis of OSA is performed through an expensive procedure, which requires an overnight stay at the hospital. This has led to several proposals based on the analysis of patients’ facial images and speech recordings as an attempt to develop simpler and cheaper methods to diagnose OSA.

Objective

The objective of this study was to analyze possible relationships between OSA and speech and facial features on a female population and whether these possible connections may be affected by the specific clinical characteristics in OSA population and, more specifically, to explore how the connection between OSA and speech and facial features can be affected by gender.

Methods

All the subjects are Spanish subjects suspected to suffer from OSA and referred to a sleep disorders unit. Voice recordings and photographs were collected in a supervised but not highly controlled way, trying to test a scenario close to a realistic clinical practice scenario where OSA is assessed using an app running on a mobile device. Furthermore, clinical variables such as weight, height, age, and cervical perimeter, which are usually reported as predictors of OSA, were also gathered.

Acoustic analysis is centered in sustained vowels. Facial analysis consists of a set of local craniofacial features related to OSA, which were extracted from images after detecting facial landmarks by using the active appearance models. To study the probable OSA connection with speech and craniofacial features, correlations among apnea-hypopnea index (AHI), clinical variables, and acoustic and facial measurements were analyzed.

Results

The results obtained for female population indicate mainly weak correlations (r values between .20 and .39). Correlations between AHI, clinical variables, and speech features show the prevalence of formant frequencies over bandwidths, with F2/i/ being the most appropriate formant frequency for OSA prediction in women. Results obtained for male population indicate mainly very weak correlations (r values between .01 and .19). In this case, bandwidths prevail over formant frequencies. Correlations between AHI, clinical variables, and craniofacial measurements are very weak.

Conclusions

In accordance with previous studies, some clinical variables are found to be good predictors of OSA. Besides, strong correlations are found between AHI and some clinical variables with speech and facial features. Regarding speech feature, the results show the prevalence of formant frequency F2/i/ over the rest of features for the female population as OSA predictive feature. Although the correlation reported is weak, this study aims to find some traces that could explain the possible connection between OSA and speech in women. In the case of craniofacial measurements, results evidence that some features that can be used for predicting OSA in male patients are not suitable for testing female population.

Differences in respiratory arousal threshold in Caucasian and Chinese patients with obstructive sleep apnoea

BACKGROUND AND OBJECTIVE

Ethnic differences in obstructive sleep apnoea (OSA) phenotype may not be limited to obesity and craniofacial factors. The aims of the study were to (i) compare the proportion of Caucasians and Chinese patients with a low respiratory arousal threshold (ArTH) and (ii) explore the influence of anatomical compromise on ArTH.

METHODS

Interethnic comparison was conducted between cohorts of Caucasian and Chinese patients from specialist sleep disorder clinics. Polysomnography and craniofacial photography were performed. A low respiratory ArTH was determined by an ArTH score of 2 or above (one point for each: apnoea-hypopnoea index (AHI) < 30/h, nadir oxygen saturation (SaO₂ ) > 82.5%, fractions of hypopnoeas > 58.3%). Anatomical compromise was stratified according to the photographic face width measurement.

RESULTS

A total of 348 subjects (163 Caucasians and 185 Chinese) were analysed. There was a significantly lower proportion of Chinese patients with moderate-severe OSA (AHI ≥ 15) who had a low ArTH (28.4% vs 48.8%, P = 0.004). This difference remained significant among those with severe OSA (AHI ≥ 30) (2.6% vs 17.1%, P = 0.02). The proportion of moderate-severe OSA Caucasians with a low ArTH was significantly less in those with severe anatomical compromise (36.6% vs 61.0%, P = 0.03), whereas there was no difference in Chinese patients (25.5% vs 31.5%, P = 0.49).

CONCLUSION

Compared to Caucasians with severe OSA, a low respiratory ArTh appears to be a less common pathophysiological mechanism in Chinese patients. Caucasians with less severe anatomical compromise exhibit evidence of a lower ArTh, an association which is absent in Chinese patients. Our data suggest that OSA mechanisms may vary across racial groups.

Three-Dimensional Evaluation of the Upper Airway in Children of Skeletal Class III

The present study was aimed to investigate the relationship of the upper airway size and craniofacial structures in 3 dimensions in growing children of skeletal Class III. Forty-seven children (19 boys and 28 girls, 9.6 ± 1.3 years of age, range 8.0-12.4 years) were selected. Twenty-three children with normal vertical development were divided into groups of insufficient maxilla and overdeveloped mandible for the airway comparison between different sagittal skeletal patterns. Thirty-two children with the same sagittal development were divided into groups of low angle, normal angle, and high angle for the comparison between different vertical skeletal developments. The upper airway and craniofacial structures were measured in cone beam computed tomography images using DOLPHIN 11.7 software. Mann-Whitney U test and Kruskal-Wallis test were used to analyze the airway differences between groups. Spearman correlated analysis was done between the upper airway size and the craniofacial pattern in the transverse dimension. The results showed that the nasopharynx was the only affected airway part between groups of insufficient maxilla and overdeveloped mandible (P <0.05). The high angle group showed smaller upper airway compared with the groups of normal angle and low angle (P <0.05). The skeletal transverse dimension was correlated with the height of velopharynx, hypopharynx, and total airway with small gender differences.

Facial phenotype in obstructive sleep apnea-hypopnea syndrome: a systematic review and meta-analysis

This systematic review and meta-analysis explores the association between facial phenotype and obstructive sleep apnea-hypopnea syndrome in adults. A comprehensive electronic (Medline via Ovid, Scopus, and Embase) database and reference search were undertaken in relation to imaging modalities for surface craniofacial assessments in subjects with sleep apnea. The outcome measures were surface facial dimensions, morphology and profile. The quality of studies was assessed and a meta-analysis conducted. The studies were weighted using the inverse variance method, and the random effects model was used to analyse data. This systematic review identified eight case-control studies. In five studies (906 participants), adults with sleep apnea showed increased weighted mean differences in neck circumference by 1.26 mm (P = 0.0001) with extensive heterogeneity between studies (I² = 93%). Only two studies (467 participants) shared the following outcomes: mandible length, lower facial height, mandible width and anterior mandible height parameters. The pooled results demonstrated obstructive sleep apnea syndrome was associated with larger parameters than controls. In conclusion, the surface facial assessment was able to demonstrate some characteristic morphological features, facilitating a meta-analysis, in adults with obstructive sleep apnea-hypopnea syndrome. The strength of these findings, however, was limited by the heterogeneity of the studies precluding the identification of a clear phenotype.

Clinical Phenotypes and Comorbidity in European Sleep Apnoea Patients

BACKGROUND

Clinical presentation phenotypes of obstructive sleep apnoea (OSA) and their association with comorbidity as well as impact on adherence to continuous positive airway pressure (CPAP) treatment have not been established.

METHODS

A prospective follow-up cohort of adult patients with OSA (apnoea-hypopnoea index (AHI) of ≥5/h) from 17 European countries and Israel (n = 6,555) was divided into four clinical presentation phenotypes based on daytime symptoms labelled as excessive daytime sleepiness ("EDS") and nocturnal sleep problems other than OSA (labelled as "insomnia"): 1) EDS (daytime+/nighttime-), 2) EDS/insomnia (daytime+/nighttime+), 3) non-EDS/non-insomnia (daytime-/nighttime-), 4) and insomnia (daytime-/nighttime+) phenotype.

RESULTS

The EDS phenotype comprised 20.7%, the non-EDS/non-insomnia type 25.8%, the EDS/insomnia type 23.7%, and the insomnia phenotype 29.8% of the entire cohort. Thus, clinical presentation phenotypes with insomnia symptoms were dominant with 53.5%, but only 5.6% had physician diagnosed insomnia. Cardiovascular comorbidity was less prevalent in the EDS and most common in the insomnia phenotype (48.9% vs. 56.8%, p<0.001) despite more severe OSA in the EDS group (AHI 35.0±25.5/h vs. 27.9±22.5/h, p<0.001, respectively). Psychiatric comorbidity was associated with insomnia like OSA phenotypes independent of age, gender and body mass index (HR 1.5 (1.188-1.905), p<0.001). The EDS phenotype tended to associate with higher CPAP usage (22.7 min/d, p = 0.069) when controlled for age, gender, BMI and sleep apnoea severity.

CONCLUSIONS

Phenotypes with insomnia symptoms comprised more than half of OSA patients and were more frequently linked with comorbidity than those with EDS, despite less severe OSA. CPAP usage was slightly higher in phenotypes with EDS.

Novel Approaches to the Management of Sleep-Disordered Breathing

In the last several years, a variety of novel approaches to the treatment of sleep-disordered breathing have emerged. This new technology holds promise in serving to re-engage with patients who have previously been lost to follow-up due to continuous positive airway pressure intolerance. With more tools at our disposal, in turn more options can be offered to patients' growing demand for alternatives that are tailored to their individual needs. The key to proper deployment of alternative therapies will often depend on identification of certain phenotypic traits that trend toward a reasonable response to a given therapy.

Facial morphology and obstructive sleep apnea

Objective:

This study aimed at assessing the relationship between facial morphological patterns (I, II, III, Long Face and Short Face) as well as facial types (brachyfacial, mesofacial and dolichofacial) and obstructive sleep apnea (OSA) in patients attending a center specialized in sleep disorders.

Methods:

Frontal, lateral and smile photographs of 252 patients (157 men and 95 women), randomly selected from a polysomnography clinic, with mean age of 40.62 years, were evaluated. In order to obtain diagnosis of facial morphology, the sample was sent to three professors of Orthodontics trained to classify patients' face according to five patterns, as follows: 1) Pattern I; 2) Pattern II; 3) Pattern III; 4) Long facial pattern; 5) Short facial pattern. Intraexaminer agreement was assessed by means of Kappa index. The professors ranked patients' facial type based on a facial index that considers the proportion between facial width and height.

Results:

The multiple linear regression model evinced that, when compared to Pattern I, Pattern II had the apnea and hypopnea index (AHI) worsened in 6.98 episodes. However, when Pattern II was compared to Pattern III patients, the index for the latter was 11.45 episodes lower. As for the facial type, brachyfacial patients had a mean AHI of 22.34, while dolichofacial patients had a significantly statistical lower index of 10.52.

Conclusion:

Patients' facial morphology influences OSA. Pattern II and brachyfacial patients had greater AHI, while Pattern III patients showed a lower index.

Speech Signal and Facial Image Processing for Obstructive Sleep Apnea Assessment

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by recurring breathing pauses during sleep caused by a blockage of the upper airway (UA). OSA is generally diagnosed through a costly procedure requiring an overnight stay of the patient at the hospital. This has led to proposing less costly procedures based on the analysis of patients' facial images and voice recordings to help in OSA detection and severity assessment. In this paper we investigate the use of both image and speech processing to estimate the apnea-hypopnea index, AHI (which describes the severity of the condition), over a population of 285 male Spanish subjects suspected to suffer from OSA and referred to a Sleep Disorders Unit. Photographs and voice recordings were collected in a supervised but not highly controlled way trying to test a scenario close to an OSA assessment application running on a mobile device (i.e., smartphones or tablets). Spectral information in speech utterances is modeled by a state-of-the-art low-dimensional acoustic representation, called i-vector. A set of local craniofacial features related to OSA are extracted from images after detecting facial landmarks using Active Appearance Models (AAMs). Support vector regression (SVR) is applied on facial features and i-vectors to estimate the AHI.