Male Obstructive Sleep Apnea Patients Research Articles

The association between endothelial dysfunction and subclinical myocardial injury in male OSA patients

BackgroundEndothelial dysfunction was shown to contribute significantly to the elevated cardiovascular risk observed in the general population. However, the relationship between endothelial dysfunction and subclinical myocardial injury in obstructive sleep apnea (OSA) patients remains unclear.MethodsThis cross-sectional study recruited 165 consecutive male patients diagnosed with OSA. All participants underwent overnight polysomnography to confirm the diagnosis and assess the severity of OSA. Subclinical myocardial injury was evaluated using high-sensitivity cardiac troponin I (hs-cTnI) measurements, while endothelial dysfunction was assessed through the peripheral arterial tonometry.ResultsEndothelial dysfunction was present in 80 (48.5%) of the subjects. Hs-cTnI was detectable in 147 (89.1%) of the participants. When compared to OSA patients without endothelial dysfunction, those with endothelial dysfunction exhibited significantly lower percentages of hypertension (23.8%versus43.5%, p=0.007) and abdominal obesity (76.3%versus88.2%, p=0.043). Patients with endothelial dysfunction frequently manifest a lower apnea-hypopnea index and oxygen desaturation index. Despite comparable median hs-cTnI levels, a higher proportion of subjects with detectable hs-cTnI levels was observed among those with endothelial dysfunction (95%versus83.5%, p=0.018). Logistic regression analysis indicated that endothelial dysfunction was significantly associated with a detectable level of hs-cTnI after adjustment for multiple confounders.ConclusionsIn male OSA patients, endothelial dysfunction appears to be potentially correlated with an increased risk of subclinical myocardial injury, as evidenced by the higher prevalence of detectable hs-cTnI levels. Further investigations are warranted to elucidate the role of endothelial dysfunction in predicting future cardiovascular mortality in this population.

The Swedish sleep apnea registry (SESAR) cohort – “Real world data” on a national level

IntroductionThe Swedish Sleep Apnea Registry (SESAR) collects clinical data from individual obstructive sleep apnea (OSA) patients since 2010. SESAR has recently been integrated with additional national healthcare data. The current analysis presents the SESAR structure and representative clinical data of a national sleep apnea cohort. MethodsClinical data from unselected patients with a diagnosis of OSA are submitted to the SESAR registry. 48 sleep centers report data from diagnosis, treatment starts with Continuous Positive Airway Pressure (CPAP), oral devices (OD), and Upper Airway Surgery (UAS). Data from follow-up are included. SESAR is linked to mandatory national healthcare data (mortality, comorbidities, procedures, prescriptions) and diagnosis-specific quality registries (e.g. stroke, heart failure, diabetes) within the DISCOVERY project. Results83,404 OSA patients have been reported during the diagnostic workup (age 55.4 ± 14.1 years, BMI 30.8 ± 6.5 kg/m2, AHI 25.8 ± 21.6n/h, respectively). At least one cardiometabolic and respiratory comorbidity is recognized in 57 % of female and 53 % of male OSA patients with a linear increase across OSA severity. In 54,468, 7,797, and 390 patients, start of CPAP, OD or UAS treatment is reported, respectively. OD patients have 4 units lower BMI and 10 units lower AHI compared to patients started on CPAP. UAS patients are characterized by 10 years lower age. The degree of daytime sleepiness is comparable between treatment groups with mean Epworth Sleepiness Scale Scores between 9 and 10. ConclusionSESAR is introduced as a large national registry of OSA patients. SESAR provides a useful tool to highlight OSA management and to perform relevant outcome research.

Sex Differences in the Expression of Cardiac Remodeling and Inflammatory Cytokines in Patients with Obstructive Sleep Apnea and Atrial Fibrillation.

Although there is a link between obstructive sleep apnea (OSA) and atrial fibrillation (AF) and numerous investigations have examined the mechanism of AF development in OSA patients, which includes cardiac remodeling, inflammation, and gap junction-related conduction disorder, there is limited information regarding the differences between the sexes. This study analyzes the impact of sex differences on the expression of cardiac remodeling, inflammatory cytokines, and gap junctions in patients with OSA and AF. A total of 154 individuals diagnosed with sleep-related breathing disorders (SRBDs) were enrolled in the study and underwent polysomnography and echocardiography. Significant OSA was defined as an apnea-hypopnea index (AHI) of ≥15 per hour. Exosomes were purified from the plasma of all SRBD patients and incubated in HL-1 cells to investigate their effects on inflammatory cytokines and GJA1 expression. The differences in cardiac remodeling and expression of these biomarkers in both sexes were analyzed. Of the 154 enrolled patients, 110 patients were male and 44 patients were female. The LA sizes and E/e' ratios of male OSA patients with concomitant AF were greater than those of control participants and those without AF (all p < 0.05). Meanwhile, female OSA patients with AF had a lower left ventricular ejection fraction than those OSA patients without AF and control subjects (p < 0.05). Regarding the expression of inflammatory cytokines and GJA1, the mRNA expression levels of GJA1 were lower and those of IL-1β were higher in those male OSA patients with AF than in those male OSA patients without AF and control subjects (p < 0.05). By contrast, mRNA expression levels of HIF-1α were higher in those female OSA patients with and without AF than in control subjects (p < 0.05). In conclusion, our study revealed sex-specific differences in the risk factors and biomarkers associated with AF development in patients with OSA.

Characteristics of genioglossus neuromuscular activity in patients with obstructive sleep apnea during drug-induced sleep

Objective: To analyze genioglossus (GG) activation responses to the negative pressure of upper airway cavity during awake and different sleep stages in patients with different obstructive sleep apnea (OSA) graduation. Methods: This prospective cohort study started from August 2019 to January 2021, recruited 42 male OSA patients aged from 21 to 59 (38.77±8.42) years. After completing whole night polysomnography (PSG) and upper airway CT, each subject underwent drug-induced sleep with simultaneous monitoring of genioglossal electromyography (GGEMG) and pressure of epiglottis (Pepi). Subjects were divided into three groups of mild OSA(7 males), moderate OSA(12 males), and severe OSA(23 males). The differences in upper airway CT measurements, parameters of GGEMG and Pepi during awake and induced sleep were compared. Statistical analysis was conducted by SPSS 21.0. Results: There was no significant difference in the GGEMG parameters between the mild and moderate groups. In wakefulness, the peak phasic GGEMG of the severe group was higher than the mild group (t=1.249, P=0.025), with no statistically difference in the corresponding Pepi. In the sleep onset, the GGEMG parameters and Pepi in severe group were higher than the other two groups. Linear regression analysis of the maximum GGEMG and maximum Pepi at the end of obstructive apnea (OA) in all moderate plus severe patients (n=35) was shown nonlinear correlation (r=0.28, P=0.694). The airway length of the glossopharyngeal cavity was linearly correlated with the maximum Pepi of OA (r=0.468, R2=0.219, P=0.005). Conclusions: The individual difference of GG activation in OSA patients is related to the severity of the disease (frequency of respiratory events) and negative pressure stimulation. In moderate and severe OSA patients, GG activity is not in harmony with the corresponding negative pressure stimulation, which may be one of the mechanisms leading to the aggravation of OSA.

Incidence disparities of obstructive sleep apnea-associated lung cancer by gender; Korean National Health Insurance data analysis.

Obstructive sleep apnea (OSA) is known to increase the risk of various cancers. By analyzing the Korea National Health Insurance Service (KNHIS) registry, the impact of OSA on the lung cancer incidence was analyzed in a retrospective cohort group. A retrospective cohort of adult patients newly registered with OSA in the KNHIS data from 2007 to 2017 was included and observed until December 2019 (12 years). The main outcome measure was newly diagnosed lung cancer. The control group was set with age and sex that matched those in the OSA group. The hazard ratio (HR) of OSA for lung cancer incidence showed a significantly reduced HR of 0.87 (95% CI, 0.82-0.93). The observed significance of this finding was limited to male OSA patients [HR, 0.84 (95% CI, 0.78-0.90)], while no significant association was found in female OSA patients [HR, 1.05 (95% CI, 0.91-1.21)], irrespective of their age. OSA patients have a lower risk of developing lung cancer, but this risk reduction is gender-specific, as female OSA patients do not show a reduction in hazard ratio.

Sex-specific associations between daytime sleepiness, chronic diseases and mortality in obstructive sleep apnea.

Excessive daytime sleepiness (EDS) is common in obstructive sleep apnea (OSA) and has been linked to adverse outcomes, albeit inconsistently. Furthermore, whether the prognostic impact of EDS differs as a function of sex is unclear. We aimed to assess the associations between EDS and chronic diseases and mortality in men and women with OSA. Newly-diagnosed adult OSA patients who underwent sleep evaluation at Mayo Clinic between November 2009 and April 2017 and completed the Epworth Sleepiness Scale (ESS) for assessment of perceived sleepiness (N = 14,823) were included. Multivariable-adjusted regression models were used to investigate the relationships between sleepiness, with ESS modeled as a binary (ESS > 10) and as a continuous variable, and chronic diseases and all-cause mortality. In cross-sectional analysis, ESS > 10 was independently associated with lower risk of hypertension in male OSA patients (odds ratio [OR], 95% confidence interval [CI]: 0.76, 0.69-0.83) and with higher risk of diabetes mellitus in both OSA men (OR, 1.17, 95% CI 1.05-1.31) and women (OR 1.26, 95% CI 1.10-1.45). Sex-specific curvilinear relations between ESS score and depression and cancer were noted. After a median 6.2 (4.5-8.1) years of follow-up, the hazard ratio for all-cause death in OSA women with ESS > 10 compared to those with ESS ≤ 10 was 1.24 (95% CI 1.05-1.47), after adjusting for demographics, sleep characteristics and comorbidities at baseline. In men, sleepiness was not associated with mortality. The implications of EDS for morbidity and mortality risk in OSA are sex-dependent, with hypersomnolence being independently associated with greater vulnerability to premature death only in female patients. Efforts to mitigate mortality risk and restore daytime vigilance in women with OSA should be prioritized.

Cortical thinning in male obstructive sleep apnoea patients with excessive daytime sleepiness.

Obstructive sleep apnoea is associated with excessive daytime sleepiness due to sleep fragmentation and hypoxemia, both of which can lead to abnormal brain morphology. However, the pattern of brain structural changes associated with excessive daytime sleepiness is still unclear. This study aims to investigate the effects of excessive daytime sleepiness on cortical thickness in patients with obstructive sleep apnoea. 61 male patients with newly diagnosed obstructive sleep apnoea were included in the present study. Polysomnography and structural MRI were performed for each participant. Subjective daytime sleepiness was assessed using the Epworth Sleepiness Scale score. Surface-based morphometric analysis was performed using Statistical Parametric Mapping 12 and Computational Anatomy 12 toolboxes to extract cortical thickness. Using the median Epworth Sleepiness Scale score, patients were divided into the non-sleepiness group and the sleepiness group. The cortical thickness was markedly thinner in the sleepiness group in the left temporal, frontal, and parietal lobe and bilateral pre- and postcentral gyri (pFWE < 0.05). There was a significant negative correlation between the cortical thickness and the Epworth Sleepiness Scale score. After adjusting for age, body mass index, and obstructive sleep apnoea severity, the Epworth Sleepiness Scale score remained an independent factor affecting the cortical thickness of the left middle temporal lobe, transverse temporal and temporal pole. Subjective daytime sleepiness is associated with decreased cortical thickness, and the Epworth Sleepiness Scale score may be of utility as a clinical marker of brain injury in patients with obstructive sleep apnoea.

Abnormal dynamic functional network connectivity in male obstructive sleep apnea with mild cognitive impairment: A data-driven functional magnetic resonance imaging study.

The purpose of this study was to investigate the dynamic functional network connectivity (FNC) and its relationship with cognitive function in obstructive sleep apnea (OSA) patients from normal cognition (OSA-NC) to mild cognitive impairment (OSA-MCI). Eighty-two male OSA patients and 48 male healthy controls (HC) were included in this study. OSA patients were classified to OSA-MCI (n = 41) and OSA-NC (n = 41) based on cognitive assessments. The independent component analysis was used to determine resting-state functional networks. Then, a sliding-window approach was used to construct the dynamic FNC, and differences in temporal properties of dynamic FNC and functional connectivity strength were compared between OSA patients and the HC. Furthermore, the relationship between temporal properties and clinical assessments were analyzed in OSA patients. Two different connectivity states were identified, namely, State I with stronger connectivity and lower frequency, and State II with lower connectivity and relatively higher frequency. Compared to HC, OSA patients had a longer mean dwell time and higher fractional window in stronger connectivity State I, and opposite result were found in State II, which was mainly reflected in OSA-MCI patients. The number of transitions was an increasing trend and positively correlated with cognitive assessment in OSA-MCI patients. Compared with HC, OSA patients showed extensive abnormal functional connectivity in stronger connected State I and less reduced functional connectivity in lower connected State II, which were mainly located in the salience network, default mode network, and executive control network. Our study found that OSA patients showed abnormal dynamic FNC properties, which was a continuous trend from HC, and OSA-NC to OSA-MCI, and OSA patients showed abnormal dynamic functional connectivity strength. The number of transformations was associated with cognitive impairment in OSA-MCI patients, which may provide new insights into the neural mechanisms in OSA patients.

Age Adjusted Sex Differences in Clinical Features of Korean Patients With Snoring or Sleep Apnea: A Single-Center Study

Background and Objectives Female are less likely to be diagnosed with obstructive sleep apnea (OSA) than male are and their symptoms are more likely to be overlooked because female usually show less typical classic symptoms of OSA, such as snoring, witnessed apnea, and daytime sleepiness. In this study, we identified sex effects among patients who complained of snoring or sleep apnea with adjusting for age.Subjects and Method This study design was retrospectively conducted to compare sex and age differences in 255 Korean patients complaining of snoring or sleep apnea by evaluating medical history, rhinomanometry, physical examination, and polysomnography.Results The sex difference in the apnea-hypopnea index decreased after 50 years of age. Female OSA patients complained of mild-to-moderate OSA with atypical symptoms. Male OSA patients showed Berlin questionnaire scores, retropalatal Muller maneuver grade, and high body mass index (BMI) as significant risk factors for OSA after adjusting for age. Female OSA patients showed retropalatal Muller maneuver grade and high BMI as significant risk factors. Berlin score was a typical risk factor in old male OSA patients.Conclusion Anatomical and hormonal factors were thought to be risk factors for OSA especially in females, but contrary to expectations, there were no risk factors in old females when adjusted for age. A careful approach should be taken to avoid overlooking sleep apnea in female.

Dynamic regional homogeneity alterations and cognitive impairment in patients with moderate and severe obstructive sleep apnea.

Background and purposePrevious studies have found that abnormal local spontaneous brain activity in patients with obstructive sleep apnea (OSA) was associated with cognitive impairment, and dynamic functional connections can capture the time changes of functional connections during magnetic resonance imaging acquisition. The purpose of this study was to investigate the dynamic characteristics of regional brain connectivity and its relationship with cognitive function in patients with OSA and to explore whether the dynamic changes can be used to distinguish them from healthy controls (HCs).MethodsSeventy-nine moderate and severe male OSA patients without any treatment and 84 HCs with similar age and education were recruited, and clinical data and resting functional magnetic resonance imaging data were collected. The dynamic regional homogeneity (dReHo) was calculated using a sliding window technique, and a double-sample t-test was used to test the difference in the dReHo map between OSA patients and HCs. We explored the relationship between dReHo and clinical and cognitive function in OSA patients using Pearson correlation analysis. A support vector machine was used to classify the OSA patients and HCs based on abnormal dReHo.ResultCompared with HCs, OSA patients exhibited higher dReHo values in the right medial frontal gyrus and significantly lower dReHo values in the right putamen, right superior temporal gyrus, right cingulate gyrus, left insula and left precuneus. The correlation analysis showed that the abnormal dReHo values in multiple brain regions in patients with OSA were significantly correlated with nadir oxygen saturation, the oxygen depletion index, sleep period time, and Montreal cognitive assessment score. The support vector machine classification accuracy based on the dReHo difference in brain regions was 81.60%, precision was 81.01%, sensitivity was 81.01%, specificity was 82.14%, and area under the curve was 0.89.ConclusionThe results of this study suggested that there was abnormal dynamic regional spontaneous brain activity in patients with OSA, which was related to clinical and cognitive evaluation and can be used to distinguish OSA patients from HCs. The dReHo is a potential objective neuroimaging marker for patients with OSA that can further the understanding of the neuropathological mechanism of patients with OSA.

Waist-hip ratio is an independent predictor of moderate-to-severe OSA in nonobese males: a cross-sectional study

BackgroundAdiposity is a well-established risk factor for obstructive sleep apnea (OSA), but whether a combination of preferable anthropometric measurements may improve the accuracy of detecting OSA is unknown. This study aimed to explore the accuracies of the waist-hip ratio (WHR) in conjunction with the body mass index (BMI) when identifying the severity of OSA.DesignA total of 2012 participants in the China-Japan Friendship Hospital from January 2018 to December 2019 underwent anthropometric measurements and an overnight home sleep test (HST). The 244 subjects who met the criteria for obstructive sleep apnea (apnea–hypopnea index (AHI) ≥ 5 events/hour) were divided into four groups: Group A (55 patients with WHR ≥ 0.9 and BMI ≥ 28 kg/m2); Group B (12 patients with WHR < 0.9 and BMI ≥ 28 kg/m2); Group C (69 patients with WHR ≥ 0.9 and BMI < 28 kg/m2); and group D (108 patients with WHR < 0.9 and BMI < 28 kg/m2).ResultsThe AHI, apnea index (AI), hypopnea index (HI), and oxygen desaturation index (ODI) were significantly different among the 4 groups (p < 0.05). The WHR was positively correlated with AHI (r = 0.22, p < 0.001), AI (r = 0.270, p = 0.004), and ODI (r = 0.286, p = 0.0022) and negatively correlated with lowest oxygen pulse saturation (LSpO2) (r = 0.246, p = 0.008) only in nonobese patients. Moreover, the WHR was found to be a screening marker for moderate-to-severe OSA in Group D (p < 0.05). When used to identify severe OSA in Group D, the WHR cut-off point of 0.873 yielded a sensitivity of 65% and specificity of 56% (p < 0.05).ConclusionIn nonobese male OSA patients, WHR is a moderate screening marker for moderate-to-severe OSA and an independent risk factor for OSA severity.

Aberrant Resting-State Functional Brain Connectivity of Insular Subregions in Obstructive Sleep Apnea.

The insular cortex is a cortical regulatory area involved in dyspnea, cognition, emotion, and sensorimotor function. Previous studies reported that obstructive sleep apnea (OSA) shows insular tissue damage and abnormal functional connections for the whole insula. The insula can be divided into different subregions with distinct functional profiles, including the ventral anterior insula (vAI) participating in affective processing, dorsal anterior insula (dAI) involved in cognitive processing, and posterior insula (PI) involved in the processing of sensorimotor information. However, the functional connectivity (FC) of these insular subregions in OSA has yet to be established. Hence, the purpose of this study was to explore the resting-state FC of the insular subregions with other brain areas and its relationship with clinical symptoms of OSA. Resting-state functional magnetic resonance imaging data from 83 male OSA patients and 84 healthy controls were analyzed by whole-brain voxel-based FC using spherical seeds from six insular subregions, namely, the bilateral vAI, dAI, and PI, to identify abnormalities in the insular subregions network and related brain regions. Ultimately, the Pearson correlation analysis was carried out between the dysfunction results and the neuropsychological tests. Compared with the healthy control group, the OSA patients exhibited disturbed FC from the dAI to areas relevant to cognition, such as the bilateral cerebellum posterior lobe, superior frontal gyrus, right middle frontal gyrus and middle temporal gyrus; decreased FC from the vAI to areas linked with emotion, such as the bilateral fusiform gyrus, superior parietal lobule, precuneus and cerebellum posterior lobe; and abnormal FC from the PI to the brain regions involved in sensorimotor such as the bilateral precentral gyrus, right superior/middle temporal gyrus and left superior frontal gyrus. The linear regression result showed that the apnea-hypopnea index was positively correlated with the increased FC between the right PI and the right precuneus (after Bonferroni correlation, P < 0.001) In conclusion, the abnormal FC between insular subregions and other brain regions were related to cognitive, emotional and sensorimotor networks in OSA patients. These results may provide a new imaging perspective for further understanding of OSA-related cognitive and affective disorders.

Characteristics of Patients with Obstructive Sleep Apnea at High Risk for Cardiovascular Disease.

Background and Objectives: To evaluate the influence of obstructive sleep apnea (OSA)-related symptoms on prevalent cardiovascular disease (CVD) in a large clinical population of patients. Materials and Methods: A total of 2127 patients (mean age 55 years, 24% women) underwent diagnostic polysomnography and were evaluated using the Epworth sleepiness scale (ESS), the Athens Insomnia Scale (AIS), and the Beck Depression Inventory (BDI). We investigated the predictive value of OSA-associated symptoms for prevalent cardiovascular disease, after adjustment for relevant confounding factors including age, obesity, and co-morbidities. Results: Patients with OSA and CVD were older and had a higher Body Mass Index (BMI); the percentage of obese patients was also higher (83% vs. 70%, p < 0001). They also had greater neck, waist, and hip circumferences and a higher waist-to-hip ratio. Excessive daytime sleepiness (ESS ≥ 10) [odds ratio (95% CI) 1.112 (0.708–1.748), p = 0.64], insomnia symptoms (AIS ≥ 6) [odds ratio (95% CI) 0.748 (0.473–1.184), p = 0.21], frequent awakenings [odds ratio (95% CI) 1.599 (1.019–2.508), p = 0.06], and nocturia [odds ratio (95% CI) 1.359 (0.919–2.009), p = 0.124] were not associated with CVD after adjustment for the previous confounders. On the other hand, depressive symptoms (BDI ≥ 10) independently predicted prevalent CVD [odds ratio (95% CI) 1.476 (1.154–1.887), p = 0.002]. Further analysis in subgroups stratified by age, BMI, and gender demonstrated that depressive symptoms predicted prevalent CVD but only in the subgroup of younger (age group < 60 years), obese (BMI group ≥ 30), and male (OR = 1.959, 95% CI = 1.209–3.175, p = 0.006) OSA patients. Conclusions: OSA patients with CVD were more likely to complain of less typical OSA symptoms and depressive symptoms compared to patients without CVD in this large clinical patient cohort, supportingthecomplexity and heterogeneityof OSA.

Clinical Factors Associated with Very Severe Obstructive Sleep Apnea in Mongolian Patients: A Case-Control Study

Objectives: To determine risk factors and clinical characteristics of obstructive sleep apnea patients (OSA) according to the severity of the value of AHI ≥ 60 (Apnea-Hypopnea Index). Methods: A hospital-based, case-control study, December 2018 - 2020. Patients were grouped by severity of AHI as moderate, severe, and very severe. Results: Of 103 male cases, 52 were very severe obstructive sleep apnea (vsOSA). The control group consisted of 16 moderate OSA (mOSA) and 35 severe OSA (sOSA) patients. The case group consisted of 52 vsOSA patients. The average age was 48.7 ± 12.6. There was statistically significant increased body mass index (p &lt; 0.003), systolic blood pressure, and abdominal circumference (p &lt; 0.006) in the vsOSA group. Moreover, on polysomnography there was less deep sleep (p &lt; 0.004), a greater arousal index (p &lt; 0.000), higher apnea-hypopnea index (p &lt; 0.000), and higher night systole pressure (p &lt; 0.010). According to a bivariate analysis, abdominal circumferences were the variable with the closest association to the vsOSA group (crude OR: 9.14, p &gt; 0.004), followed by decreased maximum saturation of O2 (crude OR: 6.6, p &gt; 0.451). Conclusion: Of male OSA patients, 50.1% have vsOSA (AHI &gt; 60) and most of them were obese and suffered from high blood pressure. Lower levels of O2 saturation and increased abdominal and neck circumferences were significant risk factors for the very severe obstructive sleep apnea group.

Microstructural changes in normal-appearing white matter in male sleep apnea patients are reversible after treatment: A pilot study.

Visually appreciable white matter (WM) changes have been described in obstructive sleep apnea (OSA). However, few data exist on the involvement of silent WM abnormalities. This prospective study investigated the microstructural integrity of normal-appearing white matter (NAWM) in male OSA patients before and after continuous positive airway pressure (CPAP) treatment, using a neuroimaging approach. Magnetic resonance imaging (MRI) was acquired from 32 participants (16 severe never-treated OSA and 16 controls). Diffusion tensor imaging (DTI) and Tract-Based Spatial Statistics (TBSS) were used to assess the microstructural NAWM changes in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). In order to evaluate the efficacy of the therapy, OSA patients underwent MRI evaluations at baseline and after 3months of treatment (follow-up). CPAP treatment significantly increased the FA in NAWM of the brain stem, corpus callosum and bilateral internal capsule of OSA patients at follow-up compared to baseline (p<0.05, TFCE-corrected). OSA patients also showed increases in AD in the corpus callosum, superior corona radiata, and internal capsule of the right hemisphere (p<0.05, TFCE-corrected) after CPAP treatment. A significant negative correlation was found between the FA of the corona radiata, corpus callosum, internal capsule, limbic structures, and neuropsychological scores at follow-up evaluation. No significant differences were found in MD and RD of NAWM in our patients after treatment. Our results demonstrate that FA and AD of NAWM in major tracts such as the corpus callosum and the internal capsule increased significantly after CPAP treatment, as a potential beneficial effect of ventilatory therapy. The recovery of NAWM alterations might also be related to the improvement in the neurocognitive profile, suggesting that nonclearly visible WM alterations may contribute to the physiopathology of OSA-related cognitive impairment.

Altered regional cerebral blood flow in obstructive sleep apnea is associated with sleep fragmentation and oxygen desaturation

Altered cerebral perfusion has been reported in obstructive sleep apnea (OSA). Using dynamic susceptibility contrast MRI, we compared cerebral perfusion between male OSA patients and male healthy reference subjects and assessed correlations of perfusion abnormalities of OSA patients with sleep parameters and neuropsychological deficits at 3 T MRI, polysomnography and neuropsychological tests in 68 patients with OSA and 21 reference subjects. We found lower global and regional cerebral blood flow and cerebral blood volume, localized mainly in bilateral parietal and prefrontal cortices, as well as multiple focal cortical and deep structures related to the default mode network and attention network. In the correlation analysis between regional hypoperfusion and parameters of polysomnography, different patterns of regional hypoperfusion were distinctively associated with parameters of intermittent hypoxia and sleep fragmentation, which involved mainly parietal and orbitofrontal cortices, respectively. There was no association between brain perfusion and cognition in OSA patients in areas where significant association was observed in reference subjects, largely overlapping with nodes of the default mode network and attention network. Our results suggest that impaired cerebral perfusion in important areas of functional networks could be an important pathomechanism of neurocognitive deficits in OSA.

Increased nocturnal arterial pulsation frequencies of obstructive sleep apnoea patients is associated with an increased number of lapses in a psychomotor vigilance task.

ObjectivesBesides hypoxaemia severity, heart rate variability has been linked to cognitive decline in obstructive sleep apnoea (OSA) patients. Thus, our aim was to examine whether the frequency domain features of a nocturnal photoplethysmogram (PPG) can be linked to poor performance in the psychomotor vigilance task (PVT).MethodsPPG signals from 567 suspected OSA patients, extracted from Type 1 diagnostic polysomnography, and corresponding results of PVT were retrospectively examined. The frequency content of complete PPGs was determined, and analyses were conducted separately for men (n=327) and women (n=240). Patients were grouped into PVT performance quartiles based on the number of lapses (reaction times ≥500 ms) and within-test variation in reaction times. The best-performing (Q1) and worst-performing (Q4) quartiles were compared due the lack of clinical thresholds in PVT.ResultsWe found that the increase in arterial pulsation frequency (APF) in both men and women was associated with a higher number of lapses. Higher APF was also associated with higher within-test variation in men, but not in women. Median APF (β=0.27, p=0.01), time spent under 90% saturation (β=0.05, p<0.01), female sex (β=1.29, p<0.01), older age (β=0.03, p<0.01) and subjective sleepiness (β=0.07, p<0.01) were significant predictors of belonging to Q4 based on lapses. Only female sex (β=0.75, p<0.01) and depression (β=0.91, p<0.02) were significant predictors of belonging to Q4 based on the within-test variation.ConclusionsIn conclusion, increased APF in PPG provides a possible polysomnography indicator for deteriorated vigilance especially in male OSA patients. This finding highlights the connection between cardiorespiratory regulation, vigilance and OSA. However, our results indicate substantial sex-dependent differences that warrant further prospective studies.

Effects of obstructive sleep apnoea severity on neurocognitive and brain white matter alterations in children according to sex: a tract-based spatial statistics study

ObjectivesTo investigate alterations in neurocognitive, attention, paediatric sleep questionnaire (PSQ) scores and whole brain white matter (WM) integrity between children with mild and severe obstructive sleep apnoea (OSA) according to sex and whether these changes are associated with OSA severity. MethodsFifty-seven children (36 males and 21 females) diagnosed with OSA were recruited for this study. Children of both sexes were divided into mild (male-MG, female-MG) and severe (male-SG, female-SG) groups according to OSA severity. Polysomnography (PSG), neurocognitive, attention and PSQ tests were compared between groups by one-way samples analysis of variance (ANOVA) F test. Diffusion tensor imaging (DTI) was scanned using a 3T GE MRI scanner and analysed by Tract-based Spatial Statistics (TBSS). Spearman correlation was calculated between DTI Eigenvalues and clinical characteristics. ResultsCompared to mild OSA patients, severe OSA patients presented greater severity of obstructive apnoea hypopnea index (OAHI), neurocognition, PSQ and attention tests in both male and female patients. Brain WM integrity in the male-SG, compared to the male-MG, demonstrated significantly reduced fractional anisotropy (FA) values in the right middle frontal gyrus and the right frontal sub-gyral regions and increased axial diffusivity (AD) values in the right inferior frontal gyrus, left parietal angular gyrus and sub-gyral regions, while no differences were found between the female-MG and female-SG. Alterations in male-SG brain regions were observably correlated with severity in male OSA patients. ConclusionsThe integrity of WM, which regulates autonomic, cognitive, and attention functions, is impaired in male, but not female, children with severe OSA.

0835 Elucidating the Effect of Sleep Apnea on Cognitive Health: A Preliminary Report

Abstract Introduction We aim to determine the cognitive domains associated with obstructive sleep apnea (OSA) age-related brain atrophy in a sample of middle-aged to older males. Methods We evaluated consecutive treatment naïve male OSA patients (AHI≥15) without dementia, stroke or heart disease (infarction, heart failure), from March to November of 2019. We obtained demographic variables, vascular risk factors, the Epworth sleepiness scale (ESS) and the Pittsburgh sleep quality index (PSQI). We also obtained computerized neurocognitive testing with the Go-NoGo Response Inhibition Test, Stroop Interference Test, Catch Game Test, Staged Information Processing Speed Test, Verbal Memory Test and Non-Verbal Memory Test. We derived domain-specific Z-scores age and education adjusted for global cognition, memory, attention, processing speed and executive function. Pearson correlation was used to evaluate bivariate associations between the sleep exposures and neurocognitive outcomes. Linear regression was used to evaluate associations between AHI and neurocognitive domains, adjusting for the ESS. Results A total of 15 participants 40 to 76 years of age, 73% of Hispanic/Latino background, completed neurocognitive testing. The average ESS was 8.2±6.0, PSQI=5.7±4.9, and AHI=48.9±25.5. Hypertension was seen in 66% and diabetes in 27%. The AHI was correlated with global cognition (r= -0.66; p=0.008), memory (r= -0.73; p=0.002) and attention (r= -0.67; p =0.007), but not executive function or processing speed. In addition, the AHI correlated with verbal memory (r= -0.76; p=0.001), but not with non-verbal memory. In adjusted models, the AHI was associated with global cognition (β= -0.60; p=0.05) and decreased memory (β= -0.85; p=0.006). However, the association with attention was explained by the ESS. The PSQI was not correlate with the cognitive domains. Conclusion In this pilot-study, the AHI was associated with decreased global cognition, and verbal memory accounting for sleepiness. Findings suggest the left-hippocampus as a region vulnerable to early age-related brain loss in OSA. Support Scientific Advisory Committee, Pilot grant, Miller School of Medicine; R21AG056952; R21HL140437.

0647 The Effect of CPAP on the Blood Flow to the Brain: A Preliminary Report

Abstract Introduction We aim to determine the effect of positive airway pressure (PAP) on total cerebral blood flow in a sample of middle-aged to older male patients with obstructive sleep apnea (OSA). Methods We evaluated consecutive treatment-naïve male OSA patients with Apnea hypopnea Index (AHI)≥15, from January to November of 2019. We obtained demographic variables, vascular risk factors, the Epworth sleepiness scale (ESS) and the Pittsburgh sleep quality index (PSQI). Brain magnetic resonance imaging (MRI) consisted of high resolution anatomical imaging and velocity encoded phase contrast MRI to measure volumetric blood flow rate to the brain, or the total cerebral blood flow (tCBF), by summation of the flow rate through the two internal carotid and vertebral arteries. Positive airway pressure at various pressures was provided during the MRI, while subjects were awake, starting at 0 cm H20, then 5 cmH20, 10, 15, and 20 cmH20. Each setting was applied for six minutes. Two subjects did not tolerate pressure setting of 20 cmH2O. Results We had a total of 11 participants’ age 40-73 years, 70% Hispanic/Latino background. The average ESS was 8.2±6.0, PSQI=5.7±4.9, and AHI=48.9±25.5. Five of the subjects had hypertension and a quarter had diabetes. In all subjects total CBF monotonically decreased with increasing PAP. The initial decreases in total CBF (PAP from 0 to 5 and 5 to 10) where significantly larger than the decrease in the higher pressure range. In two subjects the total decrease in tCBF was nearly 50%. The average tCBF was 682.3 mL/min at 0 cmH20 and 506.3 ml/min at 20 cmH20. Conclusion Incremental increases in PAP lead to substantial decrease in tCBF during wake. Substantial decrease in tCBF is possibly explained by decreasing end tidal CO2 pressure. The specific physiologic cause and the neurologic impact of prolonged decreased tCBF during CPAP therapy needs to be further investigated. Support Scientific Advisory Committee, Pilot grant, Miller School of Medicine; R21AG056952; R21HL140437; Jazz-Pharmaceutical.