Sleep apnea: clinical investigations in humans

An evaluation of the change in serum SCUBE-1 levels with CPAP treatment in patients with severe obstructive sleep apnea

OBJECTIVE

Signal peptide CUB-EGF domain-containing protein 1 (SCUBE-1) is a cell surface protein, wherein inflammation causes an increase in serum. The aim of this study was to compare serum SCUBE-1 levels in OSA patients and to investigate the serum SCUBE-1 change with CPAP treatment.

METHODS

Blood samples were obtained from 61 severe OSA patients and from 25 control subjects evaluated as simple snorers. The 61 patients with severe OSA were treated with CPAP therapy and were recalled for follow up after 1 year. Evaluation was made after 1 year of CPAP therapy.

RESULTS

Serum SCUBE-1 values were significantly higher in patients with severe OSA. The SCUBE-1 values significantly decreased after treatment with CPAP.

CONCLUSION

Serum SCUBE-1 values in OSA patients showed a significant reduction in SCUBE-1 levels following 1 year of CPAP treatment.

Mitochondrial dysfunction is associated with cognitive impairment in adults with OSA without dementia

STUDY OBJECTIVES

Increased reactive oxygen species associated with loss of mitochondrial function affect synaptic activity, which is an important mechanism underlying cognitive decline. This study assesses the role of mitochondrial proteins in neuron-derived exosomes (NDEs) on cognitive impairment in patients with obstructive sleep apnea (OSA) without dementia.

METHODS

Analyses were conducted in 268 study participants with complete polysomnography data, cognitive tests, and important clinical data available. NDEs were isolated immunochemically for enzyme-linked immunosorbent assay quantification of mitochondrial proteins, i.e., humanin and mitochondrial open reading frame of the 12S rRNA-c (MOTS-c), and synaptic protein, i.e., neurogranin (NRGN). A mediation analysis of the relationship between sleep parameters and cognition was performed using humanin, MOTS-c, and NRGN values as a mediating factor. Twenty-two patients with moderate to severe OSA who received CPAP therapy were followed up, and humanin, MOTS-c and NRGN levels were reassessed after 1 year of treatment.

RESULTS

All participants were divided into the OSA + MCI group (n = 91), OSA-MCI group (n = 89), MCI group (MCI without OSA) (n = 38) and control group (normal cognitive state without OSA) (n = 50). The mean CD63-normalized NDE levels of humanin, MOTS-c, and NRGN in the OSA + MCI group were higher than those in the OSA-MCI and control groups. The NDE levels of humanin, MOTS-c, and NRGN in the MCI group were lower than those in controls. The odds of cognitive impairment in patients with OSA were higher with higher NDE levels of humanin, MOTS-c, and NRGN (odds ratio (OR): 2.100, 95 % confidence interval (CI): 1.646-2.679, P < 0.001; OR: 5.453, 95 % CI: 3.112-9.556, P < 0.001; OR: 3.115, 95 % CI: 2.163-4.484, P < 0.001). The impaired cognitive performance was associated with higher NDE levels of humanin (β: 0.505, SE: 0.048, P < 0.001), MOTS-c (β: 0.580, SE: 0.001, P < 0.001), and NRGN (β: 0.585, SE: 0.553, P < 0.001). The relationship between sleep parameters (mean SaO2 and T90) and MoCA scores was mediated by the NDE levels of humanin, MOTS-c, and NRGN with the proportion of mediation varying from 35.33 % to 149.07 %. Receiver operating characteristic curve revealed an area under the curve of 0.905 for humanin, 0.873 for MOTS-c, and 0.934 for NRGN to predict MCI in OSA patients without dementia. Increased humanin, MOTS-c, and NRGN levels significantly decreased after CPAP treatment.

CONCLUSIONS

Mitochondrial dysfunction is implicated in cognitive impairment in OSA patients without dementia, and mainly mediates the association between intermittent hypoxia and cognitive impairment in adults with OSA without dementia. Mitochondrial dysfunction can be partially reversible by CPAP treatment. Mitochondrial proteins can be used as markers of cognitive impairment in patients with OSA.

Exploring the Shared Genetic Architecture Between Obstructive Sleep Apnea and Body Mass Index

Purpose

The reciprocal comorbidity of obstructive sleep apnea (OSA) and body mass index (BMI) has been observed, yet the shared genetic architecture between them remains unclear. This study aimed to explore the genetic overlaps between them.

Methods

Summary statistics were acquired from the genome-wide association studies (GWASs) on OSA (Ncase = 41,704; Ncontrol = 335,573) and BMI (Noverall = 461,460). A comprehensive genome-wide cross-trait analysis was performed to quantify global and local genetic correlation, infer the bidirectional causal relationships, detect independent pleiotropic loci, and investigate potential comorbid genes.

Results

A positive significant global genetic correlation between OSA and BMI was observed (r g = 0.52, P = 2.85e-122), which was supported by three local signal. The Mendelian randomization analysis confirmed bidirectional causal associations. In the meta-analysis of cross-traits GWAS, a total of 151 single-nucleotide polymorphisms were found to be pleiotropic between OSA and BMI. Additionally, we discovered that the genetic association between OSA and BMI is concentrated in 12 brain regions. Finally, a total 134 expression-tissue pairs were observed to have a significant impact on both OSA and BMI within the specified brain regions.

Conclusion

Our comprehensive genome-wide cross-trait analysis indicates a shared genetic architecture between OSA and BMI, offering new perspectives on the possible mechanisms involved.

Sleep status of older adults with sleep apnoea syndrome may vary by body mass index

Obesity and ageing are the most important risk factors for sleep apnoea syndrome (SAS); however, the role of body mass index (BMI) on sleep status in healthy older adults is unclear. To explore sleep parameters according to BMI among active older adults, we cross-sectionally examined the relationship between sleep-related parameters and BMI in 32 Japanese adults aged from 83 to 95 years without long-term care who were unaware of having SAS. Correlation and linear regression analyses were performed. Moderate or severe SAS prevalence was high in both those with low (68.8%) and high (68.8%) BMI. A higher increase in apnoea-hypopnoea index (AHI) was negatively correlated with sleep depth in the high-BMI group. In the low-BMI group, the number of awakenings and age were positively correlated with AHI. Older adults may have SAS regardless of their BMI, and the sleep status of patients with SAS may vary by BMI.

A Novel Enhancement Approach Following MVMD and NMF Separation of Complex Snoring Signals

Snoring is a prominent characteristic of sleep-disordered breathing, and its detection is critical for determining the severity of the upper airway obstruction and improving daily quality of life. Home snoring analysis is a highly invasive method, but it becomes challenging when a sleeping partner also snores, leading to distorted evaluations in such environments. In this article, we tackle the problem of complex snore signal separation of multiple snorers. This article introduces two audio-based methods that efficiently extract an individual's snoring signal, allowing for the analysis of sleep-breathing disorders in a normal sleeping environment without isolating individuals. In the first method, Principal Component Analysis (PCA) identifies the source components from the finite number of modes generated by the decomposition of the snoring mixture using Multivariate Variational Mode Decomposition (MVMD). The second method applies Blind Source Separation (BSS) based on Non-Negative Matrix Factorization (NMF) to separate the single-channel snoring mixture. Furthermore, the decomposed signals are tuned using the iterative enhancement algorithm to adequately match the source snoring signals. These methods were evaluated by simulating various real-time snoring recordings of 7 subjects (2 men, 2 women, and 3 children). The correlation coefficient between the source and its separated signal was computed to assess the separation results, exhibiting good performance of the methods used. The enhancement approach also demonstrated its efficiency by increasing the correlation over to 80% in both methods. The experimental results show that the proposed algorithms are effective and practical for separating mixed snoring signals.

Electroencephalographic slowdowns during sleep are associated with cognitive impairment in patients who have obstructive sleep apnea but no dementia

OBJECTIVES

To research the relationship between quantitative electroencephalogram (qEEG) and impaired cognitive function patients who have obstructive sleep apnea (OSA) but no dementia.

METHODS

Subjects who complained of snoring between March 2020 and April 2021 in the Sleep Medicine Center of Weihai Municipal Hospital were included. All subjects underwent overnight in-laboratory polysomnography (PSG) and were assessed using a neuropsychological scale. Standard fast fourier transform (FFT) was used to obtain the electroencephalogram (EEG) power spectral density curve, and to calculate the delta, theta, alpha, and beta relative power and the ratio between slow and fast frequencies. Binary logistic regression was used to assess the risk factors for cognitive impairment in patients who had OSA but no dementia. Correlation analysis was performed to determine the relationship between qEEG and cognitive impairment.

RESULTS

A total of 175 participants without dementia who met the inclusion criteria were included in this study. There were 137 patients with OSA, including 76 with mild cognitive impairment (OSA + MCI), 61 without mild cognitive impairment (OSA-MCI), and 38 participants without OSA (non-OSA). The relative theta power in the frontal lobe in stage 2 of non-rapid eye movement sleep (NREM 2) in OSA + MCI was higher than that in OSA-MCI (P = 0.038) and non-OSA (P = 0.018). Pearson correlation analysis showed that the relative theta power in the frontal lobe in NREM 2 was negatively correlated with Mini-Mental State Examination (MMSE) scores, Montreal Cognitive Assessment (MoCA) Beijing version scores, and MoCA subdomains scores (visual executive function, naming, attention, language, abstraction, delayed recall and orientation) outside language.

CONCLUSIONS

In patients who had OSA but no dementia, the EEG slower frequency power increased. The relative theta power in the frontal lobe in NREM 2 was associated with MCI of patients with OSA. These results suggest that the slowing of theta activity may be one of the neurophysiological changes in the early stage of cognitive impairment in patients with OSA.

Frequency of Obstructive Sleep Apnea in Patients With Cystic Fibrosis and Non-cystic Fibrosis Bronchiectasis and Its Association With Clinical Findings

OBJECTIVE

This study was designed to assess obstructive sleep apnea (OSA) in adult patients with cystic fibrosis (CF) and non-CF bronchiectasis (BE) and to relate it with clinical characteristics.

METHODS

Thirty-five CF (27 years) and 35 non-CF (24 years) BE patients were included. Demographic characteristics, medications, comorbidities, BMI, dyspnea scales, pulmonary functions, sputum cultures, exacerbations, and hospitalizations were recorded. The Epworth Sleepiness Scale (ESS) questionnaire was filled and polysomnography was performed for each patient.

RESULTS

ESS scores did not show any significant difference between CF and non-CF BE patients. Thirty-seven (53%) of all patients had OSA. There was no significant difference in OSA risk between CF and non-CF BE patients (54% vs 51%, respectively). Male gender was found to be a risk factor for OSA (68% of males vs 41% of females, respectively, p:0.026). Total sleep time, sleep efficiency, sleep latency, time spent awake after falling asleep, oxygen desaturation index, apnea-hypopnea-index (AHI), AHI in the supine position, and rapid eye movement phase did not show any significant difference between CF and non-CF patients. CF patients had significantly lower mean oxygen saturation (p:0.001) and lowest oxygen saturation (p:0.0024) levels and higher heart rate (p:0.02) compared to non-CF BE patients. Multiple logistic regression analysis of all patients revealed male gender and disease duration as risk factors for OSA (p:0.023 and p:0.041 respectively).

CONCLUSION

It is remarkable that more than half of the patients in both CF and non-CF bronchiectasis groups had OSA. Male gender and disease duration were found as risk factors for OSA.

Complement protein levels in serum astrocyte-derived exosomes are associated with cognitive impairment in obstructive sleep apnea

STUDY OBJECTIVES

An association between neuroinflammation and cognitive decline has been established. The complement system regulates neuroinflammation. Dysregulation, impairment, or inadvertent activation of complement components contribute to preclinical Alzheimer's disease. The astrocyte-derived exosome (ADE) complement proteins, including C3b and C5b-9, may be predictive biomarkers of mild cognitive impairment conversion to Alzheimer's disease dementia. We hypothesized that complement proteins might be involved in cognitive impairment during obstructive sleep apnea (OSA). The aim of our study was to explore the correlation between the complement system and mild cognitive impairment (MCI) in patients with OSA.

METHODS

All participants with subjective snoring complaints from the Sleep Medicine Center underwent polysomnography. OSA was defined as apnea-hypopnea index ≥ 5 events/h. MCI was defined as the Montreal Cognitive Assessment < 26 and met the criteria: (1) a subjective cognitive impairment; (2) an objective impairment in 1 or more cognitive domains; (3) complex instrumental daily abilities can be slightly impaired but independent daily living abilities are maintained; and (4) no dementia. The ADEs were isolated immunochemically for enzyme-linked immunosorbent assay quantification of complement proteins, including C3b, C5b-9, and CD55. The participants who received continuous positive airway pressure were followed up and their complement protein levels were reassessed after 1 year of treatment.

RESULTS

A total of 212 participants (66.98% males; mean age of 56.71 ± 10.10 years) were divided into the OSA+MCI group (n = 90), OSA-MCI group (n = 79), and controls (normal cognitive state without OSA) (n = 43). The ADE levels of C3b and C5b-9 in the OSA+MCI group were higher than those in the OSA-MCI and control groups. The C3b and C5b-9 were independently associated with cognitive impairment in patients with OSA. The relationship between apnea-hypopnea index and Montreal Cognitive Assessment scores was mediated by C3b and C5b-9. We found no linear correlation between the complement proteins and the severity of OSA. The complement proteins were negatively correlated with global cognitive performance and cognitive subdomains. The complement protein levels significantly decreased after continuous positive airway pressure treatment.

CONCLUSIONS

Complement proteins were implicated in cognitive impairment in patients with OSA and may be promising biomarkers for predicting cognitive impairment in patients with OSA.

CLINICAL TRIAL REGISTRATION

Registry: Chinese Clinical Trial Registry; Name: Study on early diagnostic markers in patients with dementia and mild cognitive impairment; URL: https://www.chictr.org.cn/; Identifier: ChiCTR1900021544.

CITATION

Li M, Sun C, Xue S, et al. Complement proteins levels in serum astrocyte-derived exosomes are associated with cognitive impairment in obstructive sleep apnea. J Clin Sleep Med. 2023;19(4):727-739.

Risk of suicide after a diagnosis of sleep apnea: A nationwide longitudinal study

Previous studies have presented evidence on the association between sleep apnea and suicidal ideation and planning, but the relationship between a clinical diagnosis of sleep apnea and suicide attempts remains unknown. We investigated the risk of suicide after a diagnosis with sleep apnea using data from a nationwide community-based population database, i.e., the Taiwan National Health Insurance Research Database. We recruited 7,095 adults with sleep apnea and 28,380 age-, sex-, and comorbidity-matched controls between 1998 and 2010 and followed them up until the end of 2011. Individuals who exhibited any (once or repeated) suicide attempts were identified during the follow-up period. The E value was calculated for unmeasured bias. Sensitivity analysis was conducted. Patients with sleep apnea were more likely to carry out any suicide attempt (hazard ratio: 4.53; 95% confidence interval: 3.48-5.88) during the follow-up period than the controls after adjusting for demographic data, mental disorders, and physical comorbidities. The hazard ratio remained significant after excluding individuals with mental disorders (4.23; 3.03-5.92). The hazard ratio was 4.82 (3.55-6.56) for male patients and 3.86 (2.33-6.38) for female patients. Consistent findings of increased risk of repeated suicide attempt were found among patients with sleep apnea. No association was found between continuous positive airway pressure treatment and suicide risk. The calculated E values support suicide risk after the diagnosis of sleep apnea. The risk of suicide was 4.53-fold higher in patients diagnosed with sleep apnea than in their counterparts without sleep apnea.

Menopausal symptoms and quality of life in female survivors treated with hematopoietic stem cell transplantation

OBJECTIVES

To assess the severity of menopausal symptoms and the correlation among different quality of life questionnaires and compare the quality of life of patients who underwent hematopoietic stem cell transplantation (HSCT) for hematological disorders with the norm group in order to facilitate personalized and directed therapeutic intervention for patients.

METHODS

We recruited women who had premature ovarian failure (POF) after HSCT for hematologic diseases in the gynecological endocrinology outpatient clinic of Peking University People's Hospital. Women with HSCT were included in the study if they had 6 months of spontaneous amenorrhea with serum follicle-stimulating hormone levels greater than 40 mIU/mL taken 4 weeks apart. The patients who had other causes of POF were excluded. During the survey, all women were required to fill out the questionnaires [Quality of Life Questionnaire (MENQOL), Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), and 36-item Short-Form (SF-36)] online. We analyzed the severity of menopausal symptoms, anxiety, and depression in Participants. In addition, differences on the SF-36 scale scores between the study group and norm groups were examined.

RESULTS

In total, 227 (93.41%) patients completed the survey and were analyzed. The severity of all symptoms is "none and mild" in MRS, MENQOL, GAD-7, and PHQ-9. On the MRS, the most common symptoms were irritability, physical and mental exhaustion, and sleep problems. The severest symptoms were sexual problems (53, 73.82%), followed by sleep problems (44, 19.38%) and mental and physical exhaustion (39, 17.18%). In the MENQOL, the most common symptoms were psychosocial and physical symptoms. The severest symptoms were sexual symptoms (35, 48.75%) followed by psychosocial symptoms (23, 10.13%). Moderate-severe scores were shown in 11.89% (27) and 18.72% (42) cases in the GAD-7 and PHQ-9, respectively. Based on SF-36, in comparison with the norm group, the HSCT participants had higher vitality scores and lower role physical, physical functioning, and role emotional scores aged 18-45. In addition, the HSCT participants had lower mental health scores aged 18-25, and lower general health scores aged 25-45. No strong correlation was observed between questionnaires in our study.

CONCLUSION

Overall, menopausal symptoms are milder in female patients after HSCT. There is no single scale that comprehensively assesses the patient's quality of life after HSCT. We need to assess the severity of various symptoms in patients using different scales.

Paroxysmal slow wave events are associated with cognitive impairment in patients with obstructive sleep apnea

BACKGROUND

Increasing evidence has supported a link between obstructive sleep apnea (OSA) and cognition, and blood-brain barrier (BBB) dysfunction which can be reflected by paroxysmal slow wave events (PSWEs) may be a potential mechanism. The purpose of our study was to investigate the correlation between the PSWEs and cognitive impairment in patients with OSA, with a focus on the possible mechanism.

METHODS

In total, 339 subjects with subjective snoring complaints from the Sleep Medicine Center underwent magnetic resonance imaging and whole-night polysomnography. OSA was defined as apnea-hypopnea index (AHI) ≥ 5 events/h. MCI was defined as the MoCA < 26 and met the criteria: (1) subjective cognitive impairment; (2) objective impairment in one or more cognitive domains; (3) slightly impaired complex instrumental daily abilities, but independent daily living abilities; and (4) no dementia. The PSWEs calculated by self-developed Python scripts were defined for EEG recordings as a median power frequency of < 6 Hz for more than five consecutive seconds. Serum cyclophilin A (CyPA) and matrix metalloproteinase-9 (MMP-9) levels and amyloid-β 42 levels in neuron-derived exosomes were determined. The participants who received continuous positive airway pressure (CPAP) were followed up and their PSWEs were recalculated after 1 year of treatment.

RESULTS

A total of 339 participants were divided into the OSA+MCI group (n = 157), OSA-MCI group (n = 118), and controls (normal cognitive state without OSA) (n = 64). The total PSWEs and the occurrence per minute of PSWEs at stage REM in the OSA+MCI group were higher than those in the OSA-MCI and control groups. The duration ratio of PSWEs at stage REM in the OSA+MCI group significantly increased. The total PSWEs and PSWEs at the F4-M1, O1-M2, and O2-M1 channels in stage REM were independently associated with cognitive impairment in OSA patients. There were positive correlations between the PSWEs and serum CyPA and MMP-9 levels in patients with OSA. The mediation analysis showed that the relationship between mean SaO₂ and percentage of sleep time spent with oxygen saturation <90% with MoCA scores was mediated by the total PSWEs (proportion of mediation 77.89% and 82.89%). The PSWEs were negatively correlated with global cognitive performance and cognitive subdomains. After 1 year of CPAP treatment, the total PSWEs, PSWEs in stage REM, and serum CyPA and MMP-9 levels decreased significantly, and MoCA scores were improved compared with baseline.

CONCLUSIONS

The PSWEs were implicated in cognitive impairment in patients with OSA, and the mechanisms of cognitive impairment due to hypoxia in OSA patients could be BBB dysfunction. The PSWEs can be used as a marker of cognitive impairment in patients with OSA.

TRIAL REGISTRATION

This trial is registered on the Chinese Clinical Trial Registry, number ChiCTR1900021544. The trial was registered on February 27, 2019.

Mediating Effect of Self-Cognitive Oral Health Status on the Effect of Obstructive Sleep Apnea Risk Factors on Quality of Life (HINT-8) in Middle-Aged Korean Women: The Korea National Health and Nutrition Examination Survey

Background: Obstructive sleep apnea and oral health are highly correlated with quality of life. The purpose of this study is to determine the mediating effect of self-cognitive oral health status on the effect of obstructive sleep apnea (OSA) risk factors on quality of life in middle-aged Korean women using the 2019 National Health and Nutrition Examination Survey data. Methods: A hierarchical regression analysis was performed on the mediating effect of self-cognitive oral health status on the effects of OSA risk factors on health-related quality of life (Korean health-related quality of life instrument with 8 items; HINT-8). Results: Self-cognitive oral health status as a parameter had a significant effect on quality of life (β = 0.713, p < 0.001). Compared to the effect of the OSA risk factor of the second stage on the quality of life (β = −1.329, p < 0.001), the input of the third stage of self-cognitive oral health was partially mediated (β = −1.280, p <0.001). Conclusions: Therefore, if middle-aged women have OSA risk factors, they should try to improve their quality of life by managing oral health as well as OSA treatment.

Assessment of Central Sleep Apnea Events in Children with Sleep-Disordered Breathing

Purpose

To determine the prevalence of central apnea (CA) events and central sleep apnea (CSA) in children with sleep-disordered breathing (SDB) and to assess the effect of tonsillectomy and adenoidectomy (TA) on CSA in children with obstructive sleep apnea (OSA). Material and Methods. The medical charts of children with SDB were reviewed to obtain information on past medical history, polysomnography (PSG) findings, and surgical management. Counts and indexes of obstructive apnea, obstructive hypopnea, and central apnea were evaluated before and after TA. The prevalence of CSA and the effect of age, gender, obesity, and comorbid conditions on CSA were assessed in children with SDB as well as in children with PSG proven OSA.

Results

Seven hundred twelve children with SDB (age range: 1 to 18 yrs, mean: 5.8 ± 3.4) were identified. CA events occurred in 640 of 712 (89.5%) patients. Of the 712 patients, 315 (44.2%) met the criteria for the diagnosis of CSA. CSA was more prevalent in toddlers and preschoolers (p < 0.001). Obese children had a higher prevalence of CSA compared to nonobese children (p < 0.001). The prevalence of CSA in patients with OSA was 45.4%. The number of CA events, CAI, and OAHI after TA was less than that of before TA (p < 0.001). Residual CSA after TA occurred in 20 children (26%).

Conclusion

Central apnea events and central sleep apnea occur in children who present to a pediatric otolaryngology clinic for evaluation of sleep disordered breathing. Central sleep apnea and obstructive sleep apnea both improve after tonsillectomy and adenoidectomy.

OSAS Severity and Occlusal Parameters: A Prospective Study among Adult Subjects with Comorbidities

Introduction: OSAS is an emerging public health problem. Early diagnosis in adults with comorbidities is the gold standard to avoid complications caused by a late diagnosis. The aim of the study, part of the SLeeP@SA project, was to identify within a population with dysmetabolic comorbidities the association of occlusal clinical signs, defined by orthodontic parameters, and of the anthropometric phenotype, with the severity of OSAS. Materials and Methods: A dedicated questionnaire containing questions regarding the presence of deep bite, augmented overjet, partial edentulism, and bruxism was completed by clinic staff. OSAS was evaluated using an unattended home PSG device, which recorded the AHI value. BMI and neck circumference were also measured. The Kolmogorov-Smirnov test was performed to evaluate the association of the AHI with occlusal clinical signs. The significance was set at p ≤ 0.05. The association of AHI with BMI and neck circumference was evaluated with the Pearson correlation coefficient. Results: In total, 199 subjects were evaluated. No statistically significant association between occlusal parameters and AHI was found, while the AHI showed a positive correlation with BMI and neck circumference. The neck circumference seemed to be a better clinical predictor for OSAS severity than BMI, especially for females. Conclusions: These results highlight how the orthodontic clinical data alone are not sufficient to establish an association between occlusal anomalies and OSAS severity, but further investigation involving a specialist orthodontic diagnosis is necessary.

Systemic Administration of Tempol, a Superoxide Dismutase Mimetic, Augments Upper Airway Muscle Activity in Obese Zucker Rats

Obstructive sleep apnea (OSA) is characterized by repetitive partial/complete collapse of the pharynx during sleep, which results in apnea/hypopnea leading to arterial oxygen desaturations and arousals. Repetitive apnea/hypopnea-arousal episodes cause hypoxia/reoxygenation cycles, which increase free radical generation and oxidative stress that cause motor/sensory nerve impairments and muscle damage. We hypothesize that antioxidants may protect and/or reverse from oxidative stress-induced damage in OSA patients. To understand the acute protective effects of antioxidants on respiratory muscles, we studied the systemic effects of a membrane permeable superoxide dismutase mimetic, Tempol, on genioglossus (EMG_GG) and diaphragmatic (EMG_DIA) electro-myographic activities, hypoglossal motoneuron (HMN) nerve activity and cardiorespiratory parameters (mean arterial blood pressure, heart rate) in adult isoflurane-anesthetized obese Zucker rats (OZR) and age-matched lean Zucker rats (LZR). Tempol dose-dependently (1-100 mg/kg) increased EMG_GG without changing EMG_DIA in OZR and LZR. Tempol increased respiratory rate and tidal volume in OZR and LZR. Tempol (1-25 mg/kg) dose-dependently increased HMN nerve activity in healthy Sprague Dawley rats. Tempol (100 mg/kg) increased EMG_GG output by 189% in OZR and 163% in LZR. With respect to mechanisms of effect, Tempol (100 mg/kg) did not augment EMG_GG after bilateral HMN transection in Sprague Dawley rats. Although future studies are warranted, available data suggest that in addition to its antioxidant and antihypertensive properties, Tempol can selectively augment EMG_GG through modulating HMN and this effect may prevent collapsibility and/or improve stability of the upper airway pharyngeal dilator muscles during episodes of partial and/or complete collapse of the upper airway in OSA human subjects.

Cardiovascular and metabolic effects of a mandibular advancement device and continuous positive airway pressure in moderate obstructive sleep apnea: a randomized controlled trial

STUDY OBJECTIVES

It has been suggested that treatment for obstructive sleep apnea (OSA) reduces cardiovascular risk. So far, knowledge is limited about the difference in the reduction of this risk between mandibular advancement device (MAD) and continuous positive airway pressure (CPAP) therapy. The aim of this study was to compare the cardiovascular effects of MAD versus CPAP therapy in patients with moderate OSA.

METHODS

Patients with an apnea-hypopnea index (AHI) of 15-30 events/h were randomized to either MAD or CPAP therapy. At baseline and after 12-months follow-up, 24-hour ambulant blood pressure measurements (ABPM) and laboratory measurements were performed. ABPM consisted of 24-hour, daytime and night-time systolic (SBP) and diastolic blood pressure (DBP), and heart rate (HR) measurements. Laboratory measurements consisted of serum lipid values, creatinine, high-sensitivity c-reactive protein, plasma glucose, hemoglobin A1c (HbA1c), proinflammatory cytokines, soluble receptor for advanced glycation end products (sRAGE), chemokines and adhesion molecules.

RESULTS

Of the 85 randomized patients with moderate OSA, data were available for 54 patients (n=24 MAD, n=30 CPAP) at 12-month follow-up and showed that AHI significantly decreased with either therapy. In the MAD group, sRAGE and HbA1c were significantly higher after 12 months follow-up compared to baseline. No significant changes were found between MAD and CPAP treatment for all outcomes.

CONCLUSIONS

Treatment of patients with moderate OSA with either MAD or CPAP therapy had no profound effects on major cardiovascular risk factors after 12-months.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: MRA Therapy Versus CPAP Therapy in Moderate OSAS; Identifier: NCT01588275; URL: https://clinicaltrials.gov/ct2/show/NCT01588275.

AI-Enabled Algorithm for Automatic Classification of Sleep Disorders Based on Single-Lead Electrocardiogram

Healthy sleep is an essential physiological process for every individual to live a healthy life. Many sleep disorders both destroy the quality and decrease the duration of sleep. Thus, a convenient and accurate detection or classification method is important for screening and identifying sleep disorders. In this study, we proposed an AI-enabled algorithm for the automatic classification of sleep disorders based on a single-lead electrocardiogram (ECG). An AI-enabled algorithm—named a sleep disorder network (SDN)—was designed for automatic classification of four major sleep disorders, namely insomnia (INS), periodic leg movement (PLM), REM sleep behavior disorder (RBD), and nocturnal frontal-lobe epilepsy (NFE). The SDN was constructed using deep convolutional neural networks that can extract and analyze the complex and cyclic rhythm of sleep disorders that affect ECG patterns. The SDN consists of five layers, a 1D convolutional layer, and is optimized via dropout and batch normalization. The single-lead ECG signal was extracted from the 35 subjects with the control (CNT) and the four sleep disorder groups (seven subjects of each group) in the CAP Sleep Database. The ECG signal was pre-processed, segmented at 30 s intervals, and divided into the training, validation, and test sets consisting of 74,135, 18,534, and 23,168 segments, respectively. The constructed SDN was trained and evaluated using the CAP Sleep Database, which contains not only data on sleep disorders, but also data of the control group. The proposed SDN algorithm for the automatic classification of sleep disorders based on a single-lead ECG showed very high performances. We achieved F1 scores of 99.0%, 97.0%, 97.0%, 95.0%, and 98.0% for the CNT, INS, PLM, RBD, and NFE groups, respectively. We proposed an AI-enabled method for the automatic classification of sleep disorders based on a single-lead ECG signal. In addition, it represents the possibility of the sleep disorder classification using ECG only. The SDN can be a useful tool or an alternative screening method based on single-lead ECGs for sleep monitoring and screening.

Increased serum levels of cyclophilin a and matrix metalloproteinase-9 are associated with cognitive impairment in patients with obstructive sleep apnea

OBJECTIVES

To investigate the relationship between serum cyclophilin A (CyPA) and matrix metalloproteinase-9 (MMP-9) levels and mild cognitive impairment (MCI) in patients with obstructive sleep apnea (OSA).

METHODS

Study subjects underwent whole-night in-laboratory polysomnography (PSG), and all participants were scored using a neuropsychological scale and peripheral blood samples were collected the next morning. The presence and severity of OSA were assessed with the apnea hypopnea index (AHI), and OSA was defined as AHI ≥5 events/hour. MCI was defined as the MoCA ≤25, and met the revised Mayo Clinic criteria. Serum CyPA and MMP-9 levels were measured with enzyme-linked immunosorbent assays (ELISAs). A univariate analysis and a logistic model were used to assess risk factors for MCI in patients with OSA. A correlation analysis was performed to estimate whether a linear relationship existed between serum CyPA and MMP-9 levels and the severity of cerebral small vessel disease (CSVD) and white matter hyperintensities (WMHs). A linear regression analysis was used to clarify the relationship between serum CyPA and MMP-9 levels and the degree of cognitive impairment in patients with OSA.

RESULTS

The 186 patients who met the criteria for inclusion and exclusion comprised 71 patients with OSA presenting with MCI (OSA + MCI), 73 patients with OSA without MCI (OSA-MCI), and 42 controls. Patients with OSA + MCI presented higher serum CyPA and MMP-9 levels than patients in the OSA-MCI (11.56 ± 4.52 ng/ml vs 9.95 ± 3.63 ng/ml, p = 0.020; 597.71 ± 204.41 ng/ml vs 523.05 ± 205.47 ng/ml, p = 0.030) and control groups (11.56 ± 4.52 ng/ml vs 8.80 ± 3.71 ng/m, p = 0.001; 597.71 ± 204.41 ng/ml vs 490.39 ± 155.07 ng/ml, p = 0.002). The logistic regression analysis revealed that both CyPA (OR: 1.111, 95% CIs: 1.012-1.219, p = 0.027) and MMP-9 levels (OR: 1.003, 95% CIs: 1.000-1.004, p = 0.011) contributed significantly to MCI in patients with OSA. In the OSA + MCI group, positive correlations were observed between serum CyPA and MMP-9 levels with Scheltens scores (r = 0.437, p = 0.000; r = 0.613, p = 0.000, respectively) and total CSVD burden scores (r = 0.318, p = 0.003; r = 0.487, p = 0.000, respectively). Serum CyPA and MMP-9 levels were linearly negatively correlated with mean oxygen saturation during sleep (mean SaO2) (r = -0.595, p = 0.000; r = -0.570, p = 0.000). There was linear correlation between mean SaO2 and MoCA scores by Pearson's correlation coefficient (r = 0.403, p = 0.000). The linear regression analysis revealed negative correlations between serum CyPA and MMP-9 levels and the Montreal Cognitive Assessment (MoCA) scores (r = -0.528, p = 0.000; r = -0.459, p = 0.000, respectively), and serum CyPA levels were negatively correlated with score of cognitive subdomainss, including visuo-executive function, attention and delayed recall. However, serum MMP-9 levels were negatively correlated with score of cognitive subdomains, including visuo-executive function and delayed recall.

CONCLUSIONS

Increased serum levels of CyPA and MMP-9 are associated with MCI in OSA patients and directly related to the severity of CSVD and WMHs. The results suggest that damage to the blood-brain barrier (BBB) may be involved in the early stages of cognitive impairment in patients with OSA.

Intervention to enhance adherence to mandibular advancement appliance in patients with obstructive sleep apnoea: study protocol for a randomised clinical trial

Background

Obstructive sleep apnoea (OSA) is a sleep-related breathing disorder characterised by the repeated episodic collapse of the upper airway during sleep, resulting in sleep deprivation, giving rise to apnoeas and hypopnoeas. Based on the severity of OSA, there are two primary treatment modalities, continuous positive airway pressure (CPAP) and mandibular advancement appliances (MAA); both are adherence-dependent. MAA is offered to those with mild to moderate OSA and is prescribed as an alternative to patients intolerable to CPAP. However, adherence to MAA treatment is variable and declines over time. Hence, the current study aims to assess the effectiveness of the stage-matched intervention, the Health Action Process Approach (HAPA), on adherence to MAA in patients with OSA.

Methods

A single-centre randomised clinical trial will be undertaken at Bart’s Health NHS Trust. Fifty-six participants with newly diagnosed OSA are planned to be enrolled in the study and randomised to intervention care (IC) and standardised care (SC) groups. Participants in the SC group will receive routine care whilst participants in the IC group will receive the stage-matched intervention, developed using the HAPA model. Data indicating MAA adherence will be collected both objectively and subjectively, from micro-sensors embedded in the MAA design and sleep diaries, respectively at 3, 6, 18 and 36 months. In addition, a range of questionnaires designed to assess risk perception, outcome expectancy, and self-efficacy (SEMSA) and quality of sleep (PSQI and ESS) and life (EQ-5DL), socio-economic and social support scales will be used.

Discussion

The currently available treatments for obstructive sleep apnoea depend entirely on the patient’s acceptance and use. There are several factors that affect cooperation and wear for example patients’ awareness of their condition, social support and psychological behaviour. In addition, mood, such as anxiety, stress, and depression, may affect wear. At the same time, we know that interventions involving more education and behaviour approaches can help patients adapt more easily to some treatments. As a result, the present trial aims to explore the potential role of these factors to maximise treatment success and minimise side effects.

Trial registration

ClinicalTrials.gov NCT04092660. Registered on September 6, 2019

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05582-1.

Factors influencing adherence to oral appliance therapy in adults with obstructive sleep apnea: a systematic review and meta-analysis

STUDY OBJECTIVES

The review aimed to identify the factors influencing adherence to oral appliance therapy in adults with obstructive sleep apnea.

METHODS

The protocol was initially registered with the International Register of Systematic Reviews (Prospero: CRD42019122615) prior to undertaking a comprehensive electronic search of databases and references without language and date restrictions. Quality assessment was undertaken using the Cochrane Collaboration's risk of bias tool and Quality in Prognosis Studies (QUIPS) tool.

RESULTS

Studies exhibited low or unclear risk of bias for the domains assessed by the respective quality assessment tools. The influence of independent variables such as disease characteristics, patient characteristics, appliance features, and psychological and social factors on adherence levels was also assessed. There was a total of 31 included studies, which consisted of 8 randomized controlled trials, 2 controlled clinical trial, 7 prospective cohorts, 11 retrospective cohorts, and the remaining 3 studies were a case-series, case-control, and a mixed-methods. All 31 included studies were subject to qualitative analysis, with only 4 studies included in the quantitative analysis. Results of the meta-analysis demonstrated increased adherence with custom-made appliances, with a pooled mean difference of -1.34 (-2.02 to -0.66) and low levels of heterogeneity (I² = 0%).

CONCLUSIONS

A weak relationship was observed between objective adherence and patient and disease characteristics, such as age, sex, obesity, apnea-hypopnea index, and daytime sleepiness, to oral appliance therapy. Nonadherent patients reported more side effects with oral appliance therapy than users and tended to discontinue the treatment within the first 3 months. Custom-made oral appliances were preferred and increased adherence reported in comparison to ready-made appliances. Further research is imperative to examine the relationship between psychosocial factors and adherence to oral appliance therapy.

Relation between IL-8 level and obstructive sleep apnea syndrome

Objective

This meta-analysis was conducted to explore the relationship between serum level of IL-8 and obstructive sleep apnea syndrome (OSAS).

Methods

Electronic databases were retrieved according to the inclusion and exclusion criteria, relevant studies exploring the relationship between serum level of IL-8 and OSAS were enrolled. Statistical analysis was performed using STATA 12.0.

Results

Totally 199 studies were retrieved, among which 10 were qualified for the inclusion criteria and were finally included in the meta-analysis with 367 cases of OSAS patients and 335 control cases. Serum level of IL-8 was higher in patients than healthy controls (Standard mean difference (SMD) = 2.16, 95% CI = 1.17–3.15, P < 0.001). The subgroup analysis based on ethnicity revealed that average serum level of IL-8 were higher in Asian and Caucasian OSAS patients than healthy controls (Asian: SMD = 2.50, 95% CI = 1.13–3.87, P < 0.001; Caucasian: SMD = 1.59, 95% CI = 0.11–3.06, P = 0.035). Further subgroup analysis based on age indicated a statistical difference in serum level of IL-8 between adult OSAS patients and healthy counterparts (SMD = 2.73, 95% CI = 1.49–3.98, P < 0.001).

Conclusion

The level of IL-8 was related to OSAS in adult patients, and increased serum IL-8 level may increase the risk of OSAS.

EEG Power Spectral Analysis of Abnormal Cortical Activations During REM/NREM Sleep in Obstructive Sleep Apnea

Objective: To characterize electroencephalogram (EEG) power in different frequency bands during rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep in patients with obstructive sleep apnea (OSA). Methods: Retrospective data on 151 patients were collected and divided into three groups: primary snoring group (AHI < 5/h), mild-moderate OSA group (6 ≤ AHI < 30/h), and severe OSA group (AHI ≥ 30/h). EEG recordings in the frontal, central, and occipital regions were extracted from both REM and NREM sleep, to compute the normalized spectral power densities in the delta, theta, alpha, sigma, beta, and gamma frequency bands, using Fast Fourier Transform. Correlations between the computed EEG power and PSG parameters were analyzed. Results: In NREM sleep, elevated normalized power spectral density (PSD) in the delta band was observed in the severe OSA group compared to the other two groups. In contrast, the PSD of the other frequency bands showed a corresponding decrease in the severe OSA group. In REM sleep, similar changes were observed in the frontal region. Delta band PSD was positively correlated with Apnea Hypopnea Index (AHI) (r = 0.33), longest time of apnea, oxygen desaturation index (ODI) (r = 0.34), percent sleep time below 90% SaO₂ (T90%) (r = 0.30), Arousal Index (ArI) (r = 0.29), and negatively correlated with N3%, minimum oxygen saturation (minSaO₂). Conclusion: Our findings provide neurophysiological evidence for pathological cortical activation during REM/NREM sleep, which may be associated with the arousals and cognitive impairments in OSA. The technique of power spectral analysis could prove a potentially useful tool in complementing traditional PSG parameters in assessing disease burden to guide therapeutic decisions.

Pharyngeal Airway Morphology in Skeletal Class III With Mandibular Asymmetry is Improved After Bimaxillary Orthognathic Surgery

PURPOSE

The relationship between pharyngeal airway morphology and jawbone movements in skeletal Class III patients with mandibular asymmetry after orthognathic surgery remains unclear. This study was to measure the changes in pharyngeal airway morphology in skeletal Class III patients with mandibular asymmetry after bimaxillary surgery and evaluate associations between changes in pharyngeal airway morphology and skeletal movements.

METHODS

In this retrospective cohort study, skeletal Class III patients who underwent bimaxillary surgery were enrolled. The predictor variable was facial symmetry status divided into 2 groups, asymmetric (Group A) and symmetric (Group B). The primary outcome variables were changes in airway parameters, including cross-sectional linear distances, cross-sectional area (CSA), minimum CSA (Min-CSA), and volume; and airway asymmetry index between the preoperative and 6-month postoperative imaging studies. Correlation analysis was performed between upper airway and skeletal changes.

RESULTS

Twenty-five patients were included in this study, with 15 patients in Group A (mean age: 23.00 years; BMI: 22.83) and 10 patients in Group B (mean age: 22.30 years; BMI: 22.48). Group A showed a higher asymmetry index than Group B at T0; however, no significant differences compared to Group B at T1. The airway volume was significantly decreased in the oropharynx in Group A at T1, whereas it showed no significant differences in Group B (P < .05). Lateral movement of B point and Menton showed positive correlations with changes in Min-CSA in the oropharynx and negative correlations with changes in airway asymmetry index (P < .05).

CONCLUSIONS

Pharyngeal airway exhibited an asymmetrical and constricted morphology in Group A before surgery. The airway morphology in Group A showed a tendency to adopt a symmetrical and less constricted shape after surgery. The airway space was reduced in the oropharynx in Group A after surgery. Surgical correction of mandibular asymmetry correlated with the improvement of pharyngeal airway morphology.

Identification of Sleep Apnea Severity Based on Deep Learning from a Short-term Normal ECG

BACKGROUND

This paper proposes a novel method for automatically identifying sleep apnea (SA) severity based on deep learning from a short-term normal electrocardiography (ECG) signal.

METHODS

A convolutional neural network (CNN) was used as an identification model and implemented using a one-dimensional convolutional, pooling, and fully connected layer. An optimal architecture is incorporated into the CNN model for the precise identification of SA severity. A total of 144 subjects were studied. The nocturnal single-lead ECG signal was collected, and the short-term normal ECG was extracted from them. The short-term normal ECG was segmented for a duration of 30 seconds and divided into two datasets for training and evaluation. The training set consists of 82,952 segments (66,360 training set, 16,592 validation set) from 117 subjects, while the test set has 20,738 segments from 27 subjects.

RESULTS

F1-score of 98.0% was obtained from the test set. Mild and moderate SA can be identified with an accuracy of 99.0%.

CONCLUSION

The results showed the possibility of automatically identifying SA severity based on a short-term normal ECG signal.

Smoking and sleep apnea duration mediated the sex difference in daytime sleepiness in OSA patients

PURPOSE

Daytime sleepiness is a common symptom of obstructive sleep apnea (OSA) and is more common in men, but the underlying mechanism remains unclear. The aim of this study was to assess whether or not sex differences in daytime sleepiness persisted after controlling for age and OSA severity and to explore the factors contributing to daytime sleepiness in patients with OSA.

METHODS

A total of 104 pairs of patients with OSA, matched by age and apnea-hypopnea index (AHI), were enrolled in this retrospective study. Demographic data were collected; daytime sleepiness was measured by the Epworth Sleepiness Scale (ESS); and polysomnography (PSG) was performed on each participant. These measurements were compared between sexes, and the factors affecting daytime sleepiness were explored with correlation and multivariate linear regression analyses.

RESULTS

Men had significantly higher ESS scores (p = 0.021) than women. Regarding demographics, BMI, neck/height ratio, and proportion of habitual smoking and alcohol intake were significantly higher in men. Regarding PSG findings, men had more rapid eye movement sleep, a longer mean apnea-hypopnea duration, and a longer mean apnea duration (MAD). Regression analysis showed that two sex-associated variables, habitual smoking (β = 0.189, p = 0.006) and MAD (β = 0.154, p = 0.024), had the strongest association with ESS scores. Further analysis revealed that MAD was significantly influenced by apnea index (β = 0.306, p < 0.001) and sex (β = - 0.193, p = 0.003).

CONCLUSION

The sex difference in daytime sleepiness persists in patients with OSA, even after matching AHI and age. The difference is mediated by sex-specific smoking habits and sex differences in apnea duration.

Associations Between Morning Salivary and Blood Cortisol Concentrations in Individuals With Obstructive Sleep Apnea Syndrome: A Meta-Analysis

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) may be associated with an increase in hypothalamic-pituitary-adrenocortical axis activity (HPA AA). We reviewed research comparing morning salivary and blood (serum and plasma) cortisol concentrations of individuals with OSAS to those of healthy controls.

METHODS

We made a systematic search without any restrictions of the PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases for relevant articles published up to August 25, 2019.

RESULTS

Sixteen studies were analyzed in this meta-analysis; five studies compared morning salivary concentrations, five compared serum concentrations, four compared plasma cortisol concentrations, and two compared both salivary and plasma concentrations. In pediatric samples, compared to healthy controls, those with OSAS had significantly lower saliva morning cortisol concentrations (MD = -0.13 µg/dl; 95% CI: 0.21, -0.04; P = 0.003). In contrast, no significant differences were observed for serum cortisol concentrations, plasma cortisol concentrations, or salivary morning cortisol concentrations between adults with and without OSAS (p = 0.61, p = 0.17, p = 0.17).

CONCLUSION

Cortisol concentrations did not differ between adults with OSAS and healthy controls. In contrast, morning salivary cortisol concentrations were lower in children with OSAS, compared to healthy controls. Given that a reduced HPA AA is observed among individuals with chronic stress, it is conceivable that children with OSAS are experiencing chronic psychophysiological stress.

Arrhythmogenic mechanisms of obstructive sleep apnea in heart failure patients

Heart failure (HF) affects 23 million people worldwide and results in 300000 annual deaths. It is associated with many comorbidities, such as obstructive sleep apnea (OSA), and risk factors for both conditions overlap. Eleven percent of HF patients have OSA and 7.7% of OSA patients have left ventricular ejection fraction <50% with arrhythmias being a significant comorbidity in HF and OSA patients. Forty percent of HF patients develop atrial fibrillation (AF) and 30%-50% of deaths from cardiac causes in HF patients are from sudden cardiac death. OSA is prevalent in 32%-49% of patients with AF and there is a dose-dependent relationship between OSA severity and resistance to anti-arrhythmic therapies. HF and OSA lead to various downstream arrhythmogenic mechanisms, including metabolic derangement, remodeling, inflammation, and autonomic imbalance. (1) Metabolic derangement and production of reactive oxidative species increase late Na+ currents, decrease outward K+ currents and downregulate connexin-43 and cell-cell coupling. (2) remodeling also features downregulated K+ currents in addition to decreased Na+/K+ ATPase currents, altered Ca2+ homeostasis, and increased density of If current. (3) Chronic inflammation leads to downregulation of both Nav1.5 channels and K+ channels, altered Ca2+ homeostasis and reduced cellular coupling from alterations of connexin expression. (4) Autonomic imbalance causes arrhythmias by evoking triggered activity through increased Ca2+ transients and reduction of excitation wavefront wavelength. Thus, consideration of these multiple pathophysiological pathways (1-4) will enable the development of novel therapeutic strategies that can be targeted against arrhythmias in the context of complex disease, such as the comorbidities of HF and OSA.

Determinants of depressive mood in coronary artery disease patients with obstructive sleep apnea and response to continuous positive airway pressure treatment in non-sleepy and sleepy phenotypes in the RICCADSA cohort

We explored determinants of depressive mood in adults with coronary artery disease and obstructive sleep apnea and response to positive airway pressure treatment in sleepy and non‐sleepy phenotypes. In this secondary analysis of the RICCADSA trial conducted in Sweden, 493 cardiac patients with obstructive sleep apnea (n = 386) or no obstructive sleep apnea (n = 107) with complete Epworth Sleepiness Scale and Zung Self‐rating Depression Scale questionnaires were included. Sleepy (Epworth Sleepiness Scale ≥10) versus non‐sleepy (Epworth Sleepiness Scale <10) patients with depressive mood (Zung Self‐rating Depression Scale score ≥50) were evaluated after 3 and 12 months of positive airway pressure treatment. In all, 133 patients (27.0%) had depressive mood (29.3% of obstructive sleep apnea versus 18.7% of no obstructive sleep apnea; p = 0.029), with a higher percentage among the sleepy phenotype (36.9% versus 24.5%; p = 0.009). In multivariate analysis, depressive mood was significantly associated with female sex, body mass index and Epworth Sleepiness Scale. Among 97 obstructive sleep apnea patients with depressive mood at baseline, there was a significant reduction in the scores at follow‐up both in the sleepy and non‐sleepy patients allocated to positive airway pressure treatment, whereas no significant changes were observed in the untreated group (p = 0.033). The device use (hr/night) predicted improvement in mood (odds ratio, 1.33; 95% confidence interval, 1.10–1.61; p = 0.003) adjusted for age, female sex, body mass index, left ventricular ejection fraction, apnea–hypopnea index and delta Epworth Sleepiness Scale score. We conclude that obstructive sleep apnea was associated with depressive mood in adults with coronary artery disease. Treatment with positive airway pressure improved mood in both phenotypes, independent of the confounding factors.

Apnea-Hypopnea Index in Healthy Class III Patients Treated With Intraoral Vertical Ramus Osteotomy: A Prospective Cohort Study

PURPOSE

The study purpose was to assess whether mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) induces obstructive apnea and hypopnea in healthy Class III patients without a history of respiratory dysfunction. We hypothesized that the apnea-hypopnea index (AHI) would not exceed 5 events per hour after surgery.

PATIENTS AND METHODS

A prospective cohort study was conducted. The sample was composed of healthy Class III patients without a history of obstructive sleep apnea treated with isolated mandibular setback surgery by the IVRO procedure at a university hospital. In-home respiratory sleep recordings (Nox T3; Nox Medical, Reykjavik, Iceland) and self-administered questionnaires were obtained before and at least 3 months after surgery. The AHI was the primary outcome variable. Other study variables were as follows: peripheral capillary oxygen saturation, oxygen desaturation index, snore index, body mass index, Epworth Sleepiness Scale, and Oral Impact on Daily Performance index. Descriptive and bivariate statistics were computed, and the significance level was set at .05.

RESULTS

The sample was composed of 8 patients. The mean age at surgery was 23.2 years (range, 18.2 to 33.4 years). The mean amount of surgical setback was 4.3 mm (range, 2.5 to 7.4 mm). The mean body mass index was 24.2 kg/m² (standard error [SE], 1.3 kg/m²) and 23.9 kg/m² (SE, 1.4 kg/m²) at the presurgical and postsurgical sleep recordings, respectively. The mean AHI was 1.3 events per hour (SE, 0.3; range, 0.1 to 2.5) before surgery and 1.8 events per hour (SE, 0.4; range, 0.3 to 3.3) after surgery. No statistically significant changes in AHI (P = .412), peripheral capillary oxygen saturation (P = .443), oxygen desaturation index (P = .194), snore index (P = .363), or Epworth Sleepiness Scale (P = .812) were observed. The patients' self-reported oral health-related quality of life was statistically significantly improved after surgery (P = .034).

CONCLUSIONS

Mandibular setback surgery with the IVRO procedure in the range of 2.5 to 7.4 mm did not induce obstructive sleep apnea, measured as an AHI above 5 events per hour, in the 8 healthy, young adult Class III patients presented in this study. More studies including larger patient samples are needed.

Barriers to acceptance and adherence to continuous positive airway pressure therapy in patients with obstructive sleep apnea: a report from Kermanshah province, western Iran

PURPOSE

Continuous positive airway pressure (CPAP) is the gold standard treatment for obstructive sleep apnea (OSA). CPAP acceptance and adherence are critical issues for optimal treatment outcome. Identifying barriers to acceptance and adherence can improve intervention development and outcomes. This study aimed to investigate the barriers to CPAP acceptance/adherence in patients with OSA in western Iran.

PATIENTS AND METHODS

Patients with OSA, who had been prescribed CPAP by the Sleep Disorders Research Center of Kermanshah University of Medical Sciences, were recruited. They were interviewed via telephone regarding acceptance (ie, CPAP use during the first 2 weeks) and adherence (ie, CPAP use 4 h/d for 70% of the nights per week). Barriers to acceptance and adherence were solicited.

RESULTS

Out of a possible sample of 101, 97 patients (79 male) were reached and included in the study. They had a mean age of 48.76 years (SD =12.04) and mean apnea/hypopnea index score of 36.06 (SD =1.87). Patients were categorized into the following acceptance/adherence groups: nonacceptance (CPAP not purchased; 72.2%), poor adherence (5.2%), and adherent (22.7%). Inability to afford a CPAP device, perception of symptom reduction/no need for treatment, and dissatisfaction with treatment were among the most common reasons for nonacceptance and poor adherence.

CONCLUSION

CPAP acceptance and adherence in western Iran are low. Approximately 70% of the patients did not accept CPAP treatment (due to not obtaining the device) and 5% did not adhere. To improve acceptance/adherence, increased access (ie, reduced cost or increased insurance coverage) and enhanced education about the benefits of the treatment are recommended. Treatment monitoring via regular follow-ups may also prove beneficial.

A Randomized Crossover Trial of a Pressure Relief Technology (SensAwake™) in Continuous Positive Airway Pressure to Treat Obstructive Sleep Apnea

Objectives/Background

Improving adherence to CPAP devices is crucial to reduce the long-term morbidity associated with OSA. SensAwake is a unique pressure relief technology that aims to promptly reduce the pressure upon sensing irregular respiration indicative of wakefulness. The purpose of this study was to compare adherence and sleep-quality outcomes in patients treated by CPAP with and without SensAwake technology.

Methods

Participants with moderate-to-severe OSA were randomized to use CPAP devices with or without SensAwake (4 weeks) before crossing over.

Results

Sixty-five patients completed both arms of the trial. There were no statistically significant differences in CPAP adherence with or without SensAwake over the study period (SensAwake ON 272.67 ± 17.06 versus SensAwake OFF 289.09 ± 15.24; p = 0.180). SensAwake reported a significantly lower system leak, 90th percentile leak, and time spent with excessive (>60 L/min) leak. Subgroup analysis suggested a trend towards improved adherence in patients with moderate-to-severe insomnia when using SensAwake.

Conclusions

Using SensAwake incurred benefit in terms of reduced leaks; however, SensAwake did not improve CPAP adherence or objective sleep quality. Further studies should investigate the accuracy of observed trends towards increased adherence using SensAwake among patients with OSA and insomnia.

Chiari 1 Malformation in a Child with Febrile Seizures, Parasomnias, and Sleep Apnea Syndrome

Introduction

The type I is the most common Chiari malformation in children. In this condition, the lower part of the cerebellum, but not the brain stem, extends into the foramen magnum at the base of the skull leading to disturbances in cerebrospinal fluid circulation and to direct compression of nervous tissue.

Case report

We describe a 4-year-old Caucasian female child with febrile seizures, headache, parasomnias, and a delay of speech. The child underwent a magnetic resonance imaging to investigate these neurological signs, disclosing a Chiari malformation type 1. The polysomnography showed a mild-moderate sleep-disordered breathing, increased number of central sleep apneas, and generalized spike waves at sleep onset.

Conclusions

Seizures have been seldom described in CM1 patients. The main reasons for performing MRI in this case were frequent seizures, a delay of speech, and headache, leading to an unexpected diagnosis of CM1. Polysomnography detected a discrete SDB.

Sleep-Disordered Breathing in Children with Recurrent Wheeze/Asthma: A Single Centre Study

The relationship between asthma and sleep-disordered breathing is bidirectional due to common risk factors that promote airway inflammation. Obstructive sleep-disordered breathing and recurrent wheeze/asthma are conditions that involve the upper and the lower respiratory system, respectively. The aim of the present study was to investigate the sleep disordered breathing in children with recurrent wheeze/asthma. This was a retrospective study concerning children older than 2 years who underwent—between January 2014 and November 2016—an in-laboratory overnight polygraphic study. We match the children between those who do or do not have recurrent wheeze/asthma disease. We examined the clinical records of 137 children. We excluded eight patients because of neurological and genetic conditions. Children with recurrent wheeze/asthma (N = 28) were younger (p = 0.002) and leaner (p = 0.013) compared to non-affected children (N = 98). Children with wheeze/asthma and unaffected ones had a similar obstructive apnea-hypopnea index (p = 0.733) and oxygen desaturation index (p = 0.535). The logistic regression analysis, in which the condition of wheeze/asthma (yes/no) was a dependent variable, while demographic (age, sex, body mass index (BMI) Z-score) and polygraphic results during sleep (obstructive apnea-hypopnea index, central apnea index, peripheral oxygen saturation (SpO₂), and snoring) were covariates, showed that children with wheeze/asthma had higher central apnea index (Exp(B) = 2.212; Wald 6.845; p = 0.009). In conclusion, children with recurrent wheeze/asthma showed an increased number of central sleep apneas than unaffected children. This finding may suggest a dysfunction of the breathing control in the central nervous system during sleep. Systemic or central inflammation could be the cause.

Upper airway asymmetry in skeletal Class III malocclusions with mandibular deviation

The purpose of this study was to investigate the relationship between bilateral differences of upper airway and mandibular morphologic patterns in subjects with skeletal Class III mandibular deviation. 47 skeletal Class III (ANB < 0°) adult patients with and without mandibular deviation were divided into 2 groups. Bilateral differences of minimum cross-sectional area, mean cross-sectional area, volume of subdivisions (nasopharynx, palatopharynx, glossopharynx, hypopharynx) were assessed paired t test. Stepwise linear regression analysis and Pearson correlation coefficients were computed between a significant pair of upper airway variables and a pair of mandibular deviation variables to examine the quantitative relationship between the upper airway asymmetry and mandibular deviation. The mean cross-sectional area and the volume of palatopharynx on the deviated side in mandibular deviated group was significantly smaller than non-deviated side. The asymmetry index of the palatopharyngeal volume showed significant correlations with CRA asymmetry (r = 0.49) and Ramus asymmetry (r = 0.54). However, in the glossopharyngeal and hypopharyngeal segment, the mandibular deviated group showed significant asymmetry, characterized by larger mean cross-sectional area and volume in deviated side. The asymmetry index of the glossopharyngeal volume and hypopharyngeal volume showed significant correlations with CRA asymmetry (r = 0.42), Me-s (r = 0.72) and Me-s (r = 0.67) respectively.

Depression as a Manifestation of Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) often results in a wide range of comorbid conditions, predominantly of the cardiovascular/respiratory, endocrine/metabolic, and neuropsychiatric symptoms. In view of the ambiguity of literature regarding the association between OSA and depression, we conducted this study to show any association between the two disorders.

OBJECTIVE

The aim of the study was to see the association between OSA and depression and to study the prevalence of OSA in patients suffering from depression.

METHODS

We performed polysomnography (PSG) studies of patients that were referred from various subspecialty clinics from July 2011 to August 2013. Psychiatric diagnosis was done using mini international neuropsychiatric interview plus scale. This was followed by application of Hamilton Depression Rating Scale (HAM-D). Standard methods of statistical analysis were used for data analysis.

RESULTS

Out of 182 patients who underwent PSG, 47 were suffering from depression with a mean age significantly more (P < 0.001) than that of other population (58.60 years vs. 53.60 years). In our 47 depressed patients, 44 (93.6%) had abnormal PSG. Based on apnea-hypopnea index score, 3 (6.8%) patients had mild, 18 (40.9%) had moderate, and 23 (52.3%) had severe OSA. The mean HAM-D score was significantly more in depression patients, (17. 35 ± 5.45) as compared to non depressive patents (8.64 ± 6.24) (P = 0.0001).

CONCLUSION

This study demonstrates significant overlap between the sleep apnea and depression. Health specialists need more information about screening for patients with OSA to ensure proper diagnosis and treatment of those with the condition. Most of the clinicians do not suspect this important comorbidity of depression in the beginning resulting in delayed diagnosis.

Long-term influence of mandibular advancement on the volume of the posterior airway in skeletal Class II-patients: a retrospective analysis

In the past, maxillomandibular advancement has resulted in considerable improvement in the volume of the posterior airway space. The objective of the present study was to find out how mandibular advancement without maxillary involvement would affect the posterior airway space in patients with mandibular retrognathism. Cone-beam computed tomographic (CT) scans were done for 20 patients before, and six months after, mandibular advancement. Cephalometric analysis at both time points included 2-dimensional and 3-dimensional assessment of the upper airway. Eight men and 12 women presented a preoperative mean (SD) Wits value of 7.4 (1.54) mm, with an airway area of 7.11 (1.88) cm² and a volume of 14.92 (4.46) cm³. Six months postoperatively they showed a Wits value of 2.7 (0.41) mm, an airway area of 11.33 (3.49) cm², and a volume of 25.7 (6.10) cm³. There was a mean (range) enlargement of 59 (22-82) % of the area and 73 (29-108) % of the volume. A preoperative Wits value of 8mm or more correlated significantly with a larger increase of the posterior airway space (p=0.002). At the same time, an improvement in the Wits value of 4.5mm or more correlated significantly with an increase in volume (p=0.016). The effect of mandibular advancement on the posterior airway space was significant, and the volumetric effect seems to be even more relevant than the two-dimensional changes.

Evaluation of the central sleep apnea in asymptomatic children with Chiari 1 malformation: an open question

INTRODUCTION

Type I is the most common Chiari malformation in children. In this condition, the lower part of the cerebellum, but not the brain stem, extends into the foramen magnum at the base of the skull leading to intermittent brain hypertension. In symptomatic children, central sleep apneas are shown in polysomnography evaluation. A central apnea index of 1/h or more is considered abnormal, but >5/h is clearly considered pathological. Therefore, central sleep apnea evaluation in pediatric age may show great age-related variability.

METHOD AND SUBJECTS

We present three patients who were assessed by polysomnography with two different scores for central sleep apneas published in the literature: the method by Scholle (2011) and the American Academy of Sleep Medicine scoring system (2012).

CONCLUSIONS

We speculated that the Scholle scoring system can be more helpful in assessing children with asymptomatic Chiari 1 malformation for a closer follow-up. More studies are needed.

Memory and Executive Screening for the Detection of Cognitive Impairment in Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) is commonly associated with cognitive dysfunction, which is more apparent in severe OSA and impairs quality of life. However, the clinical screening methods for these impairments in OSA are still limited. In this study, we evaluated the feasibility of using the Memory and Executive Screening (MES) for assessing cognitive performance in OSA.

MATERIALS AND METHODS

Twenty-four patients with nonsevere OSA and 36 patients with severe OSA participated in this study. All participants underwent comprehensive, laboratory-based polysomnography and completed assessments of cognitive function, which included both the MES and the Beijing version of the Montreal Cognitive Assessment (MoCA-BJ).

RESULTS

Both the total MES scores and 5 recall scores of the MES (MES-5R) were significantly lower in the severe OSA group than those in the nonsevere OSA group. The patients with severe OSA performed worse on the memory subtests of the MES-5R, especially on immediate recall. The sensitivity and specificity of the MES for identifying cognitive impairment in patients with OSA were 63.89% and 66.67%, respectively, for a cutoff value of <92 out of 100 points. An optimal cutoff between nonsevere and severe OSA was also set at 45 points (MES-5R) and at 0.94 points (MES ratio). Compared with the MES, the MoCA-BJ had similar sensitivity (61.11%) and specificity (66.67%).

CONCLUSIONS

The MES is an acceptable tool for detecting cognitive dysfunction in patients with OSA. The sensitivity and specificity of the MES were similar to those of the MoCA-BJ. The MES-5R and total MES scores can assess the presence and severity of cognitive impairment in patients with severe OSA.

Cognitive problems following hematopoietic stem cell transplant: relationships with sleep, depression and fatigue

Cognitive problems are a significant, persistent concern for patients undergoing hematopoietic stem cell transplant (HSCT). Sleep is important for many cognitive tasks; however, the relationship between sleep and cognitive problems for HSCT patients is unknown. This study examined the relationship between sleep and cognitive problems for HSCT patients from pre to post transplant. Patients undergoing HSCT (N=138) completed questionnaires at pre-transplant and during the 12 months following transplant. Questionnaires assessed sleep and cognitive problems as well as commonly co-occurring symptoms: depressive symptoms, fatigue and pain. Post hoc analyses examined the relationship of specific sleep problems with cognitive problems. Sleep problems covaried with cognitive problems even after controlling for depressive symptoms, fatigue and pain. Depressive symptoms and fatigue were also uniquely related to cognitive problems. Post hoc analyses suggest that sleep somnolence, shortness of breath, snoring and perceptions of inadequate sleep may contribute to the association found between sleep and cognitive problems. Findings suggest that sleep problems are associated with and may contribute to cognitive problems for HSCT patients. However, sleep problems are rarely screened for or discussed during clinic visits. Assessing and treating specific sleep problems in addition to depressive symptoms and fatigue may have implications for improving cognitive problems for HSCT patients.

Factors affecting executive functions in obstructive sleep apnea syndrome and volumetric changes in the prefrontal cortex

PURPOSE

Obstructive sleep apnea syndrome (OSAS) is associated with cognitive changes and executive functions are among the cognitive domains most affected. However, it is not completely understood which of the factor(s) among hypoxemia, repeated arousal, and sleepiness affect the executive functions. This study aims to evaluate the possible relationship between the executive functions and nocturnal parameters, Epworth Sleepiness Scale (ESS) scores, and prefrontal cortex (PFC) volumes.

PATIENTS AND METHODS

A total of 28 patients aged between 18 and 60 years who were newly diagnosed with OSAS were included in this study. The Wisconsin Card Sorting Test (WCST) and Stroop test which were used in the evaluation of executive functions were applied to all patients. Cranial magnetic resonance imaging (MRI) and volumetric measurements of the PFC were performed. Polysomnography (PSG), WCST, Stroop test, and cranial MRI were also applied to the control group which consisted of age- and education status-matched 15 healthy subjects. The correlation of WCST and Stroop tests and PFC volume, PSG parameters, and ESS scale was examined.

RESULTS

The WCST-6 test scores were statistically significantly higher in the patient group (p = 0.022; p < 0.05). Additionally, the Stroop test 5 (p = 0.043) and Stroop test-5 correction (p = 0.005) measurements were statistically significantly higher in the patient group (p < 0.05). A negative and statistically significant correlation was found between the WCST-4 and WCST-10 and ESS measurements in the patient group (r -0.452; p 0.016; p < 0.05; r -0.437; p 0.020; p < 0.05). However, there was no correlation between the PSG parameters and WCST and Stroop test scores. No statistically significant differences in the MRI volumetric measurements of the PFC were found between the patient and control groups.

CONCLUSIONS

Impairment in the attentive and executive functions in OSAS is evident. The most influential factor is excessive daytime sleepiness, rather than hypoxemia and severity of the disease.

New Rule-Based Algorithm for Real-Time Detecting Sleep Apnea and Hypopnea Events Using a Nasal Pressure Signal

We developed a rule-based algorithm for automatic real-time detection of sleep apnea and hypopnea events using a nasal pressure signal. Our basic premise was that the performance of our new algorithm using the nasal pressure signal would be comparable to that using other sensors as well as manual annotation labeled by a technician on polysomnography study. We investigated fifty patients with sleep apnea-hypopnea syndrome (age: 56.8 ± 10.5 years, apnea-hypopnea index (AHI): 36.2 ± 18.1/h) during full night PSG recordings at the sleep center. The algorithm was comprised of pre-processing with a median filter, amplitude computation and apnea-hypopnea detection parts. We evaluated the performance of the algorithm a confusion matric for each event and statistical analyses for AHI. Our evaluation achieved a good performance, with a sensitivity of 86.4 %, and a positive predictive value of 84.5 % for detection of apnea and hypopnea regardless of AHI severity. Our results indicated a high correlation with the manually labeled apnea-hypopnea events during PSG, with a correlation coefficient of r = 0.94 (p < 0.0001) and a mean difference of -2.9 ± 11.6 per hour. The proposed new algorithm could provide significant clinical and computational insights to design a PSG analysis system and a continuous positive airway pressure (CPAP) device for screening sleep quality related in patients with sleep apnea-hypopnea syndrome.

Significance of vaspin in obstructive sleep apnea-hypopnea syndrome

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a commonly-diagnosed chronic sleep disorder. It is considered to be an important independent risk factor in the development of insulin resistance (IR). Patients with OSAHS exhibit a variety of metabolic disorders, including obesity and metabolic syndrome. Visceral adipose tissue-derived serpin (vaspin) is an adipokine that is considered to be a link between obesity and IR. The present study aimed to evaluate the levels of plasma vaspin in patients with OSAHS and examine their potential correlation with sleep characteristics. A total of 20 healthy male subjects and 42 male patients with OSAHS were selected, and patients were divided into mild (n=22) and severe (n=20) OSAHS groups. The 20 patients in the severe OSAHS group received nasal continuous positive airway pressure (nCPAP) treatment for 2 months. Venous blood samples were drawn from all patients in a fasting state prior to and subsequent to nCPAP treatment, which were used to measure the levels of biochemical indicators. The sleep parameters and serologic index changes were compared prior to and following treatment. The values of contractive pressure (SBP), neck circumference (NC), waist circumference (WC), waist-to-hip ratio (WHR), body mass index (BMI) and hip circumference (HC) in the two OSAHS groups were significantly increased compared with those in the control group. In addition, the levels of vaspin in OSAHS patients were markedly increased and vaspin was revealed to be positively associated with fasting blood sugar, fasting insulin, triglycerides, homeostasis model assessment-IR, apnea-hypopnea index (AHI), NC, WC, BMI and WHR (P<0.05). After 2 months of nCPAP treatment, the SBP and AHI were significantly reduced. In conclusion, vaspin may have an important role in OSAHS patients with IR and treatment using nCPAP may improve the condition of OSAHS patients.

Declarative and Non-declarative Memory Consolidation in Children with Sleep Disorder

Healthy sleep is essential in children’s cognitive, behavioral, and emotional development. However, remarkably little is known about the influence of sleep disorders on different memory processes in childhood. Such data could give us a deeper insight into the effect of sleep on the developing brain and memory functions and how the relationship between sleep and memory changes from childhood to adulthood. In the present study we examined the effect of sleep disorder on declarative and non-declarative memory consolidation by testing children with sleep-disordered breathing (SDB) which is characterized by disrupted sleep structure. We used a story recall task to measure declarative memory and Alternating Serial Reaction time (ASRT) task to assess non-declarative memory. This task enables us to measure two aspects of non-declarative memory, namely general motor skill learning and sequence-specific learning. There were two sessions: a learning phase and a testing phase, separated by a 12 h offline period with sleep. Our data showed that children with SDB exhibited a generally lower declarative memory performance both in the learning and testing phase; however, both the SDB and control groups exhibited retention of the previously recalled items after the offline period. Here we showed intact non-declarative consolidation in SDB group in both sequence-specific and general motor skill. These findings suggest that sleep disorders in childhood have a differential effect on different memory processes (online vs. offline) and give us insight into how sleep disturbances affects developing brain.

[The syndrome of increased upper airways resistance: What are the clinical features and diagnostic procedures?]

The upper airway resistance syndrome "UARS" is a poorly defined entity, often described as a moderate variant of the obstructive sleep apnea syndrome. It is associated with respiratory effort-related arousal, absence of obstructive sleep apnea, and absence of significant desaturation. It is a relatively common condition that predominantly affects non-obese young adults, with no predominance in either sex. The degree of upper airway collapsibility during sleep of patients with UARS is intermediate between that of normal subjects and that of patients with mild-to-moderate sleep apnea syndrome. Craniofacial and palatal abnormalities are often noted. Patients frequently complain of a functional somatic syndrome, especially daytime sleepiness and chronic fatigue. Polysomnography with esophageal pressure measurements remains the gold standard diagnostic test. The absence of any neurological abnormality gives UARS a good prognosis and it is potentially reversible if treated early. However, some studies suggest that untreated UARS has an increased risk of arterial hypertension. It can also evolve into obstructive sleep apnea.