Severe Obstructive Sleep Apnea Syndrome Group Research Articles

Evaluation of Choroidal Thickness and Retinal Vessel Density with Serum HIF-1α and TNF-α Level in Patients with OSAS

Purpose To reveal changes in choroidal thickness, retinal vessel density, and serum HIF-1α and TNF-α levels in obstructive sleep apnea syndrome (OSAS) and their correlation. Methods This prospective case-control study included 118 patients divided into mild-to-moderate OSAS (n = 40), severe OSAS (n = 39), and a control group (n = 39). Choroidal thickness was evaluated with OCT, vessel density with OCTA, AHI index with polysomnography, and serum HIF-1α and TNF-α levels were analyzed using the enzyme-linked immunosorbent assay. Results The serum HIF-1α values of the participants in the mild-moderate OSAS and severe OSAS groups were [893.25(406.7–2068) and 1027(453–2527), respectively], and were both significantly higher than the control group [(521.5(231.6–2741))] (p < 0.001). Serum TNF-α levels did not differ significantly between the groups (p = 0.051).). Subfoveal choroidal thickness (SFCT) values of the severe OSAS groups were significantly lower than the control group (p < 0.05). The superficial and deep capillary plexus vascular density (SVD and DVD) values of the severe OSAS group were lower than the control group (p < 0.05). Serum HIF-1α and TNF-α levels of all participants were negatively correlated with both their SVD values (p < 0.05, r: –0.220 and p < 0.05, r: –0.252, respectively) and their DVD values (p < 0.001, r: –0.324 and p = 0.001, r: –0.299, respectively). Conclusions Increased serum levels of inflammatory mediators (HIF-1α ve TNF-α) in OSAS cause a decrease in SFCT, SVD, and DVD, which is an indication of systemic vascular damage. Further research on developing treatment strategies to modulate TNF-α ve HIF-1α may help recede vascular morbidity in OSAS patients.

Cephalometric analysis with magnetic resonance imaging in patients with obstructive sleep apnea syndrome

Objectives: The study aimed to assess soft tissues and bony structures in patients with snoring and obstructive sleep apnea syndrome (OSAS) by magnetic resonance imaging (MRI) cephalometry and to investigate the correlation between the degree of OSAS with cephalometric measures. Patients and Methods: The prospective study included 137 adult patients (86 males, 51 females; mean age: 44.2±11.8; range 21 to 70 years) admitted with complaints of snoring or witnessed apnea between December 2020 and June 2023. Polysomnography and MRI cephalometry were performed for each patient. According to the polysomnography results, patients were assigned to one of the following groups: simple snorers [apnea-hypopnea index (AHI) &lt;5; n=25], mild OSAS (AHI between 5 and 15; n=37), moderate OSAS (AHI between 15 and 30; n=36), and severe OSAS (AHI &gt;30; n=39). The SNA (sella, nasion-point A), SNB (sella, nasion-point B), submental fat thickness, retropalatal and retro glossal distance, tongue, uvula, basion, and hyoid-related cephalometric measurements were evaluated with MRI cephalometry. Results: The H-A (hyoid-point A) values were found to be higher in the severe OSAS patients than in other groups (p&lt;0.001, p&lt;0.001 and p&lt;0.05, respectively). The PNS-UT (posterior nasal spine-uvula tip) values of the patients in the severe OSAS group were found to be higher than patients in both the snoring and moderate OSAS groups (p&lt;0.001). The SNB values of the patients in the mild OSAS group were found to be higher than the patients in the snoring group (p&lt;0.05). In the parameters of UW (uvula thickness), PAS-RG (posterior airway space-retroglossal distance), and H-B (hyoid-point B), statistically meaningful differences were found only between the simple snorers group and the group with severe OSAS. Conclusion: In OSAS patients, some important distances, angles, and lengths can be evaluated by avoiding ionizing radiation with MRI cephalometry.

SnoreLab Application in the Assessment of Obstructive Sleep Apnea Syndrome: A Pilot Study

Background: SnoreLab (Version 5.3, Reviva Softworks Ltd., London, UK) is featured as the number one mobile application (app) for measuring snoring intensity and duration. The aim of this study was to conduct a comparative analysis between the results derived from SnoreLab and polysomnography (PSG). Methods: Male and female patients between 18 and 75 years of age, seeking medical counseling for suspected obstructive sleep apnea syndrome (OSAS), were considered eligible to participate in this study. Exclusion criteria were psychological or neurological disorders, drug or alcohol abuse, and inability to follow instructions. All patients underwent one overnight in-hospital PSG with simultaneous snoring recording using the SnoreLab app. Results: Nineteen patients (15 men, 4 women) aged 50.9 ± 10.5 years were included. The overall cohort exhibited a Snore Score of 24.8 ± 22.2 alongside an AHI of 15.1 ± 17.0, indicating moderate OSAS. Interestingly, elevated Snore Scores were observed in both the simple snoring (30.7 ± 19.2) and severe OSAS group (35.2 ± 21.4) (Kruskal–Wallis p-value = 0.176). The analysis of the Spearman’s test did not reveal a statistically significant correlation between PSG parameters and the Snore Score. Conclusions: While SnoreLab records snoring, it is not designed for screening sleep apnea. Although SnoreLab may not replace PSG for use in diagnosis, it could serve as a complementary tool for monitoring snoring and to improve the interaction between patients and clinicians when integrated into a suitable clinical assessment.

Prevalence of Obstructive Sleep Apnea Using Home Sleep Test in Taiwan During the Coronavirus Disease Pandemic.

Obstructive sleep apnea syndrome (OSAS) is a common disorder associated with serious sequelae. The current gold standard diagnostic method, polysomnography, is costly and time consuming and requires patients to stay overnight at a facility. This study aimed to reveal the prevalence of OSAS in general adult population using a home sleep test (HST) during the coronavirus disease 2019 (COVID-19) pandemic. This prospective cohort study was conducted by the Department of Otolaryngology, Taipei City Hospital, Taipei, Taiwan, between January 2020 and December 2021. A total of 1372 patients aged 30-70 years completed an HST using a Type 3 portable sleep monitor (PM). The apnea-hypopnea index (AHI) was analyzed to assess the association of OSAS with age, body mass index (BMI), sex, Epworth Sleepiness Scale (ESS) and the Sleep Apnea Risk Assessment questionnaire (STOP-Bang questionnaire) rating. The mean age of the patients (782 men, 57%; 590 women, 43%) was 49.24 ± 11.04 years. OSAS was detected in 954 (69.5%) patients with 399 (29.1%) mild OSAS; 246 (17.9%) moderate OSAS; and 309 (22.5%) severe OSAS. Among these, the prevalence of moderate-to-severe OSAS was 143 (10.4%) in women and 412 (30.0%) in men. The mean age was the highest (51.29 ± 11.29) in the mild OSAS group and lowest (47.08 ± 10.87) in the healthy group. OSAS severity was greater with increasing BMI, 23.39 ± 3.44 in the healthy group and 29.29 ± 5.01 in the severe OSAS group. A positive correlation was also noted between the ESS/STOP-Bang questionnaire rating and OSAS severity. The prevalence of OSAS in Taiwan was 69.5% in our study. It showed strong evidence that OSAS has important public health consequences and PMs are simple, fast, feasible, and cost-effective tools for OSAS screening in the home environment, especially during the COVID-19 pandemic.

Cognitive Functions in Patients with Moderate-to-Severe Obstructive Sleep Apnea Syndrome with Emphasis on Executive Functions and Decision-Making.

Patients with obstructive sleep apnea syndrome (OSAS) have cognitive dysfunction in many aspects, however, these patients' decision-making function remains unclear. In this study, the Game of Dice Task (GDT) was used to investigate the function of decision making in patients with OSAS. 30 participants with moderate to severe OSAS and 27 participants with no or mild OSAS diagnosed by sleep breathing monitor were selected from June 2021 to March 2022. Risky decision making was tested through the GDT with known risk probability. General demographic information and background cognitive functions, such as the overall cognitive functioning and executive functioning, were tested to establish baseline data. There were no significant differences in gender, age, and years of education between the two groups. During the GDT, the moderate to severe OSAS group opted for the safety option at a statistically significant lower rate when compared to the no or mild OSAS group (7.53 ± 4.43 vs. 10.26 ± 4.26, p = 0.022). The moderate to severe OSAS group utilized the higher risk option than the group with no or mild OSAS (10.47 ± 4.43 vs. 7.74 ± 4.26, p = 0.022). The utilization rate of negative feedback in the moderate and severe OSAS group was lower than that in the no or mild OSAS group (7.50, 52.50 vs. 28.57, 100.00, p = 0.001). At the end of the GDT, the moderate and severe OSAS group was more likely to have negative total assets than the patients with no or mild OSAS (-1846.67 ± 2587.20 vs. 300.00 ± 1509.97, p < 0.001). Multiple linear regression analysis shows that there is a negative correlation between the selection of risk options and negative feedback utilization in the GDT. Patients with moderate and severe OSAS displayed impaired decision-making throughout the study. Impaired decision-making is related to executive processes and may be caused by diminished prefrontal cortex functioning. However, the functions of memory, attention, language, abstraction, and orientation are relatively retained.

Alterations of ocular surface parameters in patients with obstructive sleep apnea syndrome.

This study aimed to evaluate changes in ocular surface parameters among obstructive sleep apnea syndrome (OSAS) patients. 44 healthy volunteers (88 eyes) and 27 OSAS patients (54 eyes) were recruited in our cross-sectional study. 14 patients were classified as mild&moderate OSAS, and 13 patients were classified as severe OSAS. For evaluating the ocular surface, the following tests were conducted: the height of tear meniscus (TMH), first non-invasive tear break-up time (FNITBUT), mean non-invasive tear break-up time (MNITBUT), the score of Meibomian gland dropout area (Meiboscore), the tear test of anesthesia-free Schirmer I (SIT), corneal fluorescein staining (CFS), partial blinks rate (PBR), the lipid layer thickness (LLT), ocular surface disease index (OSDI). The results obtained from the study were analyzed and compared among the groups. FNITBUT, MNITBUT, and TMH were lower. OSDI, CFS, Meiboscore and PBR were higher in the OSAS group than those in the control group. The mild&moderate as well as the severe OSAS subgroups had statistically significantly lower TMH, and higher OSDI and PBR than the control group. Meanwhile, we found there were no significant differences between two OSAS subgroups. CFS was higher in the severe OSAS group than the mild&moderate OSAS group. Significantly lower FNITBUT, MNITBUT and higher Meiboscore were observed in the severe OSAS subgroup than in the control group, and MNITBUT was higher in severe OSAS objects than in the mild&moderate OSAS objects. LLT and SIT did not exhibit significant differences among control and OSAS subgroups. FNITBUT and MNITBUT showed significantly negative correlations with BMI, while Meiboscore showed a significant positive correlation with AHI. Patients with OSAS have a tendence of dry eyes, whereas control subjects do not. This indicates us that the OSAS patients should pay more attention to ocular surface care.

Evaluation of the auditory findings of patients with obstructive sleep apnea syndrome

ObjectivesTo investigate the effects of hypoxia occurring in patients with Obstructive Sleep Apnea Syndrome (OSAS) on Auditory evoked late latency, Auditory brainstem response, and the contralateral suppression of otoacoustic emissions. Materials and methods46 patients diagnosed with OSAS were divided into groups as moderate and severe based on their Apnea Hipopnea Index (AHI) values. The control group consisted of 22 healthy individuals. All participants underwent an Auditory Brainstem Response (ABR) test, Auditory Evoked Late Latency Response (LLR), and Contralateral Suppression Otoacoustic Emission (CS-OAE). FindingsThere was no statistical difference between the OSAS group and the control group regarding P1 latency, N1 latency, and P1 and N1 wave amplitude (p > 0.05). In ABR, statistically significant differences were found between the control, moderate OSAS, and severe OSAS groups in wave I in the right and left ear (p < 0.05). In the analyses performed for the otoacoustic emission frequencies with and without contralateral suppression of the right and left ear, suppression was not observed at some frequencies, and this was regarded as statistically significant (p < 0.05). ConclusionIt is considered that OSAS does not have cortical effects but impacts the brainstem region and the cochlea. Bilateral impact, especially observed in wave I of ABR, is prominent on the auditory nerve. Considering that the medial olivo-cochlear (MOC) system is affected in patients with OSAS, it is thought that these patients are inadequate in suppressing noise, and this may cause various problems, particularly the inability to distinguish speech in noisy environments.

Agmatine, telomerase and trace minerals levels in patients with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a disease characterized by repetitive, partially or complete upper airway obstructions resulting in hypoxia and bioelectrical wakefulness reactions along with sleep. There is a limited and different information on the biochemical pathways that may determine harmful effects in OSAS patients with different disease severity. Hence, we aimed to estimate the plasma levels of polyamine agmatine, which has many effects on the central nervous system, telomerase and trace minerals in patients with OSAS. The study included 90 volunteer patients diagnosed with OSAS and divided into three groups of 30 people each according to the apnea-hypopnea index (AHI) score: mild, moderate and severe. Nocturnal blood oxygen saturation percentage (SpO2) and body mass index (BMI) were measured. Plasma agmatine level was defined by ultra-high-pressure liquid chromatography (UHPLC), plasma trace elements (Cu, Co, Mg, Mo, Zn, Se) level by inductively coupled plasma mass spectrometer (ICP-MS) and serum telomerase level by enzyme-linked immunosorbent assay (ELISA) method. It was found that SpO2 value decreased as the disease progressed and showed a negative correlation with BMI, Co and Se plasma levels. The levels of agmatine and telomerase were shown to lower in patients with severe OSAS group compared to other groups. Keywords: agmatine, sleep apnea syndrome, SpO2, telomerase, trace minerals

Relationships between 25-Hydroxyvitamin D Levels and Obstructive Sleep Apnea Severity in Children: An Observational Study.

The prevalence of hypovitaminosis D is increasing worldwide. Vitamin D deficiency is supposed to play a role in sleep disturbances, but the complex relationships between hypovitaminosis D and pediatric obstructive sleep apnea syndrome (OSAS) are still incompletely understood. This study was aimed to retrospectively investigate the vitamin D status and significant clinical, laboratory, and instrumental variables in a cohort of pediatric patients with OSAS and to assess the possible relationship between serum vitamin D levels and OSAS severity. We consecutively enrolled all children aged 2-14 years admitted to our Pediatric Clinic from 1 July 2018 to 30 November 2020 for sleep-disordered breathing. Each patient underwent standard overnight in-hospital polygraphic evaluation, measurement of serum 25-hydroxyvitamin D (25(OH)D) levels, and clinical and laboratory investigation. A total of 127 children with OSAS were included. The 25(OH)D levels and BMI of OSAS patients were compared with those of an age-matched control group: the serum 25(OH)D levels were significantly lower in OSAS patients than in controls (22.4 vs. 25.5 ng/mL; p-value = 0.009), whereas no differences in the BMI percentile were found between the two groups. The mean value of 25(OH)D was not significantly lower (20.9 ng/mL) in the severe OSAS group compared with the mild (23.0 ng/mL) and moderate (23.3 ng/mL) OSAS groups (p-value = 0.28). Our findings indicate a relationship between vitamin D status and OSAS in children and suggest that severe cases of OSAS have lower vitamin D levels. Future, more extensive prospective studies are needed to confirm such preliminary findings.

Ocular Surface in Patients With Obstructive Sleep Apnea Syndrome: Evaluation of Clinical Parameters and Impression Cytology.

To evaluate the effect of obstructive sleep apnea syndrome (OSAS) on the ocular surface and conjunctival cytology and the relationship between the findings and disease severity. One hundred six eyes of 106 patients (77 patients with OSAS and 29 control subjects) were included in the study. Twenty-three patients with an apnea-hypopnea index (AHI) of 5 to 15 were classified as mild OSAS (group 1), 27 patients with an AHI of 15 to 30 were classified as moderate OSAS (group 2), and 27 patients with an AHI≥30 were classified as severe OSAS (group 3). The following tests were used to evaluate the ocular surface: tear break-up time (TBUT), Schirmer I test, ocular surface disease index (OSDI), and conjunctival impression cytology (CIC). The results obtained from the tests were analyzed and compared between the groups. The mean value of the Schirmer I test was 15.03±10.16 (1-35) mm in the control group, whereas it was found as 13.39±8.80 (3-35) mm, 9.85±7.81 (1-30) mm, and 9.41±7.53 (2-35) mm in the mild, moderate, and severe OSAS groups, respectively, and the difference between the groups was significant ( P =0.002). Although the mean TBUT score was 9.83±5.03 (3-23) seconds in the control group, it was 11.04±6.22 (3-20), 6.26±3.48 (1-16), and 5.44±3.09 (1-10) in the mild, moderate, and severe OSAS groups, respectively, and the difference between the groups was significant ( P <0.001). Although the mean OSDI score was 12.76±14.84 (range, 0-41.65) in the control group, it was 11.52±12.95 (range, 0-44.40), 25.06±19.45 (range, 0-75), and 20.31±19.87 (range, 0-77.70) in the mild, moderate, and severe OSAS groups, respectively, and the difference between the groups was significant ( P =0.015). Although the mean CIC stage was 0.47±0.60 (0-2) in the control group, it was 0.89±0.74 (0-2), 1.52±0.75 (0-3), and 1.83±0.69 (1-3) in the mild, moderate, and severe OSAS groups, respectively, and the difference between groups was significant ( P <0.001). In addition to decreased tear production and TBUT, cytological changes including squamous metaplasia were detected between patients with OSAS and the control group.

Use of eustachian tube dysfunction questionnaire in obstructive sleep apnea syndrome

OBJECTIVE: This study aimed to investigate the eustachian tube dysfunction (ETD) of patients with obstructive sleep apnea syndrome (OSAS) using the Eustachian Tube Dysfunction Questionnaire-7 (ETDQ-7). METHODS: The study included 96 patients (78 males, 18 females; mean age 39.4±12.2 years; range 18 to 64 years) diagnosed with OSAS by polysomnographic evaluation. All patients were administered the ETDQ-7. Age, sex, presence of septum deviation, Epworth Sleepiness Scale, apnea-hypopnea index (AHI), lowest oxygen saturation, and oxygen desaturation index parameters were recorded. The patients were divided into mild, moderate, and severe OSAS groups according to the AHI score. The parameters of the cases in each group were compared, and their correlation with the ETDQ-7 scores was evaluated. RESULTS: The fourth question score and the total score in the group with severe OSAS were significantly higher than the groups with mild and moderate OSAS (p&lt;0.05 for all). The fourth question score and the total score were significantly higher in the group with moderate OSAS than the group with mild OSAS (p&lt;0.05 for all). There was a significant positive correlation between the oxygen desaturation index and the scores of questions 1, 3, 4, 6, and 7 and the total score (p&lt;0.05 for all). CONCLUSION: Questionnaire scores were higher in patients with severe OSAS compared to mild to moderate OSAS patients. Based on this data, we would like to emphasize that OSAS cases may develop ETD and other related pathologies.

Evaluation of the effect of obstructive sleep apnea syndrome on retinal microvascularity by optical coherence tomography angiography

PurposeUsing optical coherence tomography angiography (OCTA), we sought to determine whether there are retinal microvascular changes in patients with obstructive sleep apnea syndrome (OSAS). MethodThe study included 56 patients diagnosed with OSAS by polysomnography [21 patients with mild OSAS (group 1), 14 with moderate OSAS (group 2) and 21 with severe OSAS (group 3)], and 26 healthy individuals as a control group (group 4). The vascular densities of the superficial capillary plexus and deep capillary plexus of the retinal segmentations, together with the foveal avascular zone (FAZ) width, were measured for all participants, using OCTA. ResultCompared with the control group, vascular densitiy in whole image of superficial capillary plexus were found to be significantly lower in group 2. In addition, vascular densitiy in fovea region of superficial capillary plexus was significantly lower in group 1 than the control group. In deep capillary plexus, vascular densitiy of whole image, superior hemi and nasal regions were found to be significantly lower in group 2 and group 3 compared with the control group. Parafoveal region in group 3 had significantly lower vascular densities than the controls. A significantly larger FAZ was also found in group 1 and group 3 in the deep capillary plexus, compared with the controls. ConclusionWe detected smaller vascular densities in both the superficial capillary plexus and deep capillary plexus and a larger deep capillary plexus FAZ in OSAS patients. Therefore, OCTA may be useful as a non-invasive method to understand the systemic effects of OSAS.

The relationship between disease severity and GDF-15 in individuals diagnosed with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is characterized with interruption of sleep with apnea attacks and is associated with various diseases such as metabolic syndrome. GDF-15 (Growth differentiation factor 15) is a cytokine belonging to the transforming growth factor – β superfamily and it has been found to be associated with chronic heart failure, acute pulmonary embolism, and acute attacks of chronic obstructive pulmonary disease (COPD). It was aimed to evaluate the relationship between disease severity and mean GDF-15 in patients diagnosed with OSAS. Our study was carried out with 75 patients with OSAS. GDF-15 levels were checked by in the morning fasting blood test. Among the 75 patients, 27 constituted the mild, 22 constituted the moderate and 26 constituted the severe OSAS groups. The mean ages of the patients were not significantly different between groups (53.17±10, 54.61±10.2 and 53.5±11.6 respectively; p&gt;0,05). GDF-15 levels were not significantly different between groups separately (p&gt;0.05). There was only a weak positive relationship between GDF-15 and NREM and REM (p&lt;0.05). In our study, it was revealed that there was no significant relationship between the OSAS severity groups and GDF-15. Our determination of a positive relationship with NREM and REM may have been related to reduction of minute ventilation experienced in OSAS-diagnosed patients, tachycardic fluctuations, their more severe nature and increased right ventricular pressure. Consequently, our current knowledge indicates that GDF-15 is not much guiding in the prediction and monitoring of OSAS severity.

Do complete blood count parameters predict diagnosis and disease severity in obstructive sleep apnea syndrome?

Inflammation and platelet activation play a role in the pathogenesis of obstructive sleep apnea syndrome (OSAS). In this study, it was aimed to investigate the effectiveness of the systemic inflammation markers, the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and WMR (white blood cell count (WBC) to mean platelet volume (MPV) ratio), in determining the severity of OSAS. The study included 207 patients who visited the pulmonology polyclinic between 1 and 31 January 2020 with complaints of snoring, apnea periods during sleep and sleepiness and were assessed with polysomnography (PSG) with the indication of hospitalization. The patients were grouped based on their apnea-hypopnea index (AHI) scores as 54 patients with AHI<5 as the control group, 41 patients with AHI=5-15 as the mild, 54 patients with AHI=15-30 as the moderate and 58 patients with AHI>30 as the severe OSAS groups. From the complete blood counts of the patients, NLR, PLR and WMR were calculated. The demographic characteristics of the patient and control groups were assessed by comparing PSG and blood parameters. The mean age of the 207 patients included in the study was 54.56±10.24 years. Among the patients, 58.5% were male, and 41.5% were female. Between the control and OSAS groups, there were significant differences in terms of the WBC and lymphocyte counts (p=0.004 and p=0.035). In terms of the NLR and PLR values, there was no significant difference among the OSAS groups (p=0.723 and p=0.309). WMR had a significant difference in the OSAS groups (p=0.001). It was determined that WMR was valuable especially in distinguishing severe OSAS from the other groups. In our study, where OSAS severity and complete blood count parameters assessed as inflammatory markers were examined, it was identified that the NLR and PLR levels were not very determinant in predicting either OSAS or its severity, and among these parameters, WMR was more significant, and it was determinant in distinguishing severe OSAS. Therefore, we believe it is needed to plan new studies without losing time over these markers in the diagnosis of OSAS, determination of its severity and its monitoring.

Efficacy of a Smart Antisnore Pillow in Patients with Obstructive Sleep Apnea Syndrome.

Objective Untreated obstructive sleep apnea syndrome (OSAS) increases the risk of cardiovascular, dementia, and motor vehicle accident events. However, continuous positive airway pressure (CPAP) which is the gold standard treatment is not acceptable for many patients with OSAS. Development of devices for the patients of nonadherence to CPAP is necessary. Materials and Methods We evaluated the effect of the smart antisnore pillow (SAP) in patients with OSAS in a prospective, noncontrolled, nonrandomized, pilot study. According to the apnea-hypopnea index (AHI), they were divided into two groups: mild-to-moderate OSAS group and severe OSAS group. Single-night polysomnography (PSG) with application of a SAP was performed. Thirty patients, 15 males and 15 females, 33–82 years old (mean age, 59.3 ± 12.9 years), completed the smart antisnore pillow therapy test. Among them, 23 patients had mild-to-moderate OSAS. Results The SAP significantly improved the snore number (p = 0.018), snore index (p = 0.013), oxygen denaturation index (p = 0.001), total AHI (p = 0.002), and supine AHI (p = 0.002) in the mild-to-moderate OSAS group, but there was no significant improvement in the severe OSAS group. Conclusions We concluded that the SAP is an effective positional therapy device for patients with OSAS of mild-to-moderate severity.

Evaluation of retinal vessel density and foveal avascular zone measurements in patients with obstructive sleep apnea syndrome.

To compare retinal capillary plexus vessel densities, choroidal thickness, optic disc vessel densities and foveal avascular zone measurements between normal subjects and subjects with obstructive sleep apnea syndrome (OSAS) using spectral-domain OCT angiography (OCTA). Forty eyes of patients with overall OSAS, 20 eyes of patients with mild-moderate OSAS, 20 eyes of patients with severe OSAS on polysomnography and 21 controls were evaluated with the RTVue-XR Avanti OCTA (Optovue, Inc., Fremont, CA). Superficial and deep retinal capillary plexus vessel densities, choroidal thickness and foveal avascular zone (FAZ) parameters (area, diameter, acircularity index of the FAZ, foveal density-300) were measured for all subjects. Superficial capillary plexus vessel densities of the groups were similar. Deep capillary plexus (DCP) vessel densities of all three OSAS groups decreased in the parafoveal region (< 0.001). In the perifoveal region, DCP vessel densities were decreased in the Overall OSAS group (p = 0.023) and in the Severe OSAS group (p = 0.021), whereas it was similar in the Mild-moderate OSAS group. Choroidal thickness decreased in all three OSAS groups (p < 0.001). All FAZ measurements and foveal density-300 measurements were similar compared to the control group. Our findings indicate that in severe OSAS patients, deep parafoveal, perifoveal vascular densities decrease and the choroid layer becomes thinner. When evaluating a patient with OSAS, it should be kept in mind that there may be eye involvement due to the disease.

Lack of association between obstructive sleep apnea syndrome and specular microscopic features of thecorneal endothelium.

Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent episodes of hypoxemia and hypercapnia during sleep. The aim of this study was to determine whether OSAS causes significant changes in corneal endothelium detectable by specular microscopy. This prospective, cross-sectional study compared the specular microscopic features of the corneal endothelium of patients with OSAS and age-and gender-matched controls. Patients diagnosed with OSAS by polysomnography in the sleep unit were classified using apnea-hypopnea indexes into two groups as mild-moderate OSAS group and severe OSAS group. All participants were divided into three age groups: 30-45, 46-60, and > 60years. Corneal endothelial cell density (ECD), percentage of hexagonal cells (Hex), and coefficient of variation of cell area (CV) were obtained using a non-contact specular microscope. The measurements of each group were compared statistically. A total of 66 patients (51.1 ± 9.4years) and 88 controls (49.2 ± 10.5years) were examined. The mild-moderate OSAS group and the severe OSAS group had no significant differences in measures of specular microscopy compared with the controls (ECD, p = 0.84; Hex, p =0.18; CV, p = 0.41). The mean values of ECD, Hex, and CV were 2552.56 ± 302.49 cells/mm2, 54.13 ± 8.13%, and 36.41 ± 5.92, respectively, in the mild-moderate OSAS group; 2510.52 ± 377.12 cells/mm2, 54.85 ± 8.68%, and 34.77 ± 5.02, respectively, in the severe OSAS group; 2543.37 ± 286.94 cells/mm2, 51.89 ± 9.09%, and 36.03 ± 5.32, respectively, in the control group. There were no significant differences in corneal endothelial features between patients and controls. Although OSAS causes systemic hypoxia, its effects do not appear to result in corneal endothelial alterations detectable by specular microscopy.

Plasma Homocysteine and Autonomic Nervous Dysfunction: Association and Clinical Relevance in OSAS.

Objective Elevated plasma homocysteine (Hcy) is an independent risk factor for cardiovascular diseases, but the precise mechanism of Hcy in cardiovascular disease remains elusive. This study is aimed at evaluating the association between Hcy levels and autonomic nervous system and at investigating their clinical relevance in obstructive sleep apnea syndrome (OSAS). Methods A total of 191 subjects with OSAS were enrolled for this cross-sectional study. Heart rate variability (HRV) represents the status of the autonomic nervous system and is a well-known index that allows studying the autonomic modulation. HRV and polysomnography parameters were collected based on Holter monitors and polysomnography system. The software computed all the basic HRV parameters including SDANN, SDNN and pNN50. Correlation analyses between Hcy and HRV parameters and echocardiographic parameters were performed. Results Compared with the mild-moderate OSAS group, the prevalence of male and smoking and Hcy levels were considerably higher in the severe OSAS group (P = 0.01, P = 0.02, and P = 0.01, respectively). Also, there were significant linear relationships between Hcy quartiles with the proportion of severe OSAS (P = 0.01 for the trend). Interesting, there is a negative linear correlation between SDANN and Hcy quartiles (P = 0.02 for the trend). Spearman's correlation analysis showed a significant negative correlation between SDANN and Hcy levels (r = −0.17, P = 0.02). Interestingly, the relationship of it remains significant after adjustment for clinical covariates (r = −0.15, P = 0.04). However, echocardiographic parameters were not significantly correlated with Hcy or HRV parameters (all P > 0.05). Conclusions Elevated plasma Hcy level is linearly correlated with cardiac autonomic nervous function disorders in patients with OSAS.

Evaluation of effects of positive airway pressure treatment on retinal fiber thickness and visual pathways using optic coherence tomography and visual evoked potentials in the patients with severe obstructive sleep apnea syndrome.

Hypoxia during sleep in obstructive sleep apnea syndrome (OSAS) increases intracranial pressure, decreases cerebral perfusion pressure, and alters vascular supply to the optic nerve. Pattern visual evoked potential (pVEP) has revealed that it causes alterations in the optic nerve, and optic coherence tomography has shown that it causes alterations in the retinal and macular layers. To detect and compare possible alterations in macula and peripapillary retinal nerve fiber thickness (pRNFL) using OCT and in the optic nerve pathways using pVEP before and after positive airway pressure (PAP) in the patients with severe OSAS. Thirty patients who were diagnosed as having severe OSAS in the neurology-sleep outpatient clinic and 30 healthy control subjects were included in the study. Ophthalmic examinations were performed prior to (month 0) and after (month 6) PAP treatment, and pVEP (peak time [PT] and amplitude) and OCT parameters (peripapillary retinal-macular layers) were compared. In the comparison between the severe OSAS (before treatment) and control groups, thinning was found in pRNFL (average, nasal, inferior) and in the macular layers (external and internal superior quadrants) (p < 0.05). pVEP investigation revealed increased PT in P100 and N145 waves and decreased amplitude of N75-P100 waves. In the comparisons before and after PAP treatment, a decrease in PT of N75 and P100 waves and increase in N75-P100 amplitudes were found. In the pRNFL, significant thickening was found in the layers with thinning before treatment, whereas no significant thickening was found in macular layers, except for the fovea. It was shown that PAP treatment in patients with severe OSAS prevents hypoxia without causing alterations in intraocular pressure and thus reduces inflammation and causes thickening in the pRNFL and macular layers.

Correlation between severity of obstructive sleep apnea syndrome and red cell distribution width in elderly patients

To investigate the correlation between the severity of obstructive sleep apnea syndrome (OSAS) and red cell distribution width (RDW) in elderly patients. A cross-sectional study was conducted among 311 elderly patients diagnosed with OSAS in the snoring clinic between January, 2015 and October, 2016 and 120 healthy controls without OSAS from physical examination populations in the General Hospital of PLA. The subjects were divided into control group with apnea-hypopnea index (AHI) &lt;5 (n=120), mild OSAS group (AHI of 5.0-14.9; n=90), moderate OSAS group (AHI of 15.0-29.9; n=113) and severe OSAS group (AHI ≥ 30; n=108). The clinical characteristics and the results of polysomnography, routine blood tests and biochemical tests of the subjects were collected. Multiple linear regression analysis was used to examine the correlation between OSAS severity and RDW. The levels of RDW and triglyceride were significantly higher in severe OSAS group than in the other groups (P &lt; 0.01). The levels of fasting blood glucose and body mass index were significantly higher in severe and moderate OSAS groups than in mild OSAS group and control group (P &lt; 0.05 or P &lt; 0.01). Multiple linear regression analysis showed that AHI was positively correlated with body mass index (β=0.111, P=0.032) and RDW (β=0.106, P=0.029). The area under ROC curve of RDW for predicting the severity of OSAS was 0.687 (P=0.0001). The RDW increases as OSAS worsens and may serve as a potential marker for evaluating the severity of OSAS.