Obstructive Sleep Apnea Syndrome Subjects Research Articles

Association between Red Blood Cell Distribution Width and Obstructive Sleep Apnea Syndrome: A Systematic Review and Meta-Analysis.

Although polysomnography is the gold standard method to diagnose obstructive sleep apnea syndrome (OSAS), there is an ongoing quest for simpler and relatively inexpensive biomarkers of disease presence and severity. To address this issue, we conducted a systematic review of the potential diagnostic role of the red blood cell distribution width (RDW), a routine hematological parameter of red blood cell volume variability, in OSAS. A total of 1478 articles were initially identified in the databases PubMed, Web of Science, Scopus, Embase, and Google Scholar, from their inception to February 2023, and 20 were selected for final analysis. The RDW was significantly higher in OSAS than in non-OSAS subjects (SMD = 0.44, 95% CI 0.20 to 0.67, p < 0.001; low certainty of evidence). In univariate meta-regression, the mean oxygen saturation (SpO2) was significantly associated with the effect size. No significant between-group differences were observed in subgroup analyses. Notably, in OSAS subjects, the RDW SMD progressively increased with disease severity. In conclusion, these results suggest that the RDW is a promising biomarker of OSAS (PROSPERO registration number: CRD42023398047).

Saliva Analysis of pH and Antioxidant Capacity in Adult Obstructive Sleep Apnea Patients.

Background: Obstructive sleep apnea syndrome (OSAS) may be associated with and activates the stress response system, and variation in the physiological antioxidant capacity of body fluids. Our aim was to evaluate the variation of pH and antioxidant capacity on the saliva of obstructive sleep apnea subjects (OG) compared to a control group (CG). Method: Fifty subjects with moderate/severe OSAS were recruited in Tor Vergata Hospital and compared with 20 healthy subjects CG. The buffer and the antioxidant capacity of the samples were quantified measuring the pH and the percentage of total salivary antioxidant capacity (%TAC), which refers to the reduced glutathione salivary concentration (GSH). Moreover, the protein concentration and the gelatinolytic activity of metalloproteinases were quantified. Results: The data showed that the pH value is slightly more alkaline in OSAS subjects; however, it is not directly related to the severity of OSAS. The %TAC was found to be significantly reduced by 86.2% in the OG. Proteins of saliva from the OG were found 1.5 times more concentrated than in the healthy sample. The gelatinolytic activity of metalloproteinases of healthy and OSA did not show statistically significant changes. Conclusions: The salivary samples from OSAS compared to CG show an alteration of the oxidative state, the pH buffering power, and protein concentrations, inducing conditions that can easily evolve chronic gingivitis. Further investigations are necessary to evaluate the feasibility of using salivary fluid for the early diagnosis of oral or systemic problems in OSAS subjects.

Obstructive Sleep Apnea and Periodontal Disease: A Systematic Review.

Background and Objectives: The objective of this study was to evaluate the association between periodontal disease and obstructive sleep apnea syndrome (OSAS). Materials and Methods: Electronic search using PubMed, Scopus, LILACS, and Cochrane library was carried out for randomized controlled trials, cohort, case-control, longitudinal and epidemiological studies on humans published from January 2009 until September 2020. The participants had to be male and female adults who were diagnosed with OSAS either by overnight polysomnography (carried out at a sleep laboratory or at home) or by a home sleep testing monitor (Apnea Risk Evaluation System). Methodological quality assessment was carried out using the Newcastle-Ottawa Quality Assessment Scale (NOS) for case-control studies while an adapted form of NOS was used for cross-sectional studies. Results: Ten studies fulfilled the inclusion criteria of our review, 5 were case-control studies, and 5 cross-sectional. Sample size ranged from 50 to 29,284 subjects, for a total of 43,122 subjects, 56% of them were male, their age ranged from 18 to 85 years old. The heterogeneity among the studies regarding the classification of periodontal disease, and the different methods for OSAS severity assessment, complicated the comparison among the studies. Conclusions: There is low evidence of a possible association between OSAS and periodontitis. The pathophysiological mechanism, cause-effect, or dose-response relationship are still unclear. Further studies are needed and should use a precise classification of OSAS subjects, while the new classification of periodontitis from the World Workshop of Chicago 2017 should be used for the periodontal assessment.

Obstructive Sleep Apnea Syndrome: A Preliminary Navigated Transcranial Magnetic Stimulation Study.

PurposeAn increase in resting motor threshold (RMT), prolonged cortical silent period duration (CSP), and reduced short-latency afferent inhibition (SAI), confirmed with previous transcranial magnetic stimulation (TMS), suggest decreased cortical excitability in obstructive sleep apnea syndrome (OSAS). The present study included MRI of OSAS patients for navigated TMS assessment of the RMT, as an index of the threshold for corticospinal activation at rest, and SAI as an index of cholinergic neurotransmission. We hypothesize to confirm findings on SAI and RMT with adding precision in the targeting of motor cortex in OSAS.Subjects and MethodsAfter acquiring head MRIs for 17 severe right-handed OSAS and 12 healthy subjects, the motor cortex was mapped with nTMS to assess the RMT and SAI, with motor evoked potentials (MEPs) recorded from the abductor-pollicis brevis (APB) muscle. The 120%RMT intensity was used for the SAI by a paired-pulse paradigm in which the electrical stimulation to the median nerve is followed by magnetic stimulation of the motor cortex at inter-stimulus intervals (ISIs) of 18–28 ms (ISIs18-28). The SAI control condition included a recording of MEPs without peripheral stimulation. Latency and amplitude of MEP at RMT at 120%RMT for eleven different at ISIs18-28 were analyzed.ResultsThe study showed a significantly lower percentage deviation of MEP amplitude at ISIs(18-28ms) from the control condition between OSAS and healthy subjects (U=44.0, p=0.01). The intensity of stimulation at RMT was significantly higher in OSAS subjects (U=55.0, p=0.04*). Correlation analysis showed that BMI significantly negatively correlated (ρ=−0.47) with MEP amplitude percentage deviation in OSAS patients.ConclusionThe nTMS study results in increased RMT, and reduced cortical afferent inhibition in OSAS patients for SAI at ISIs18-28, confirming previous findings of impaired cortical afferent inhibition in OSAS. Future nTMS studies are desirable to elucidate the role of RMT and SAI in diagnostics and treatment of OSAS, and to elucidate the usefulness of nTMS in OSAS research.

Behaviour of carbonyl groups in several clinical conditions: Analysis of our survey.

Protein carbonylation is a marker of oxidative protein damage, that is likely involved in the pathogenesis of several diseases. The aim of this study was to evaluate the protein carbonyl (PC) groups in different clinical conditions. It included different groups of subjects: 81 trained subjects; 23 subjects with mild essential hypertension; 31 middle-aged subjects with metabolic syndrome (MS); 106 subjects with MS not selected for age (subdivided into two subgroups, with and without diabetes mellitus); 91 obese adults subdivided in two subgroups (BMI 30-35 Kg/m2 and BMI > 35 kg/m2); 48 subjects with obstructive sleep apnea syndrome (OSAS) subdivided in accordance with the apnea/hypopnea index (AHI); 27 subjects with chronic kidney disease (CKD) on conservative therapy; 31 subjects with CKD on haemodialysis treatment; and 50 subjects with juvenile myocardial infarction. PC groups were reduced in trained subjects in comparison with sedentary controls, while no variation was observed in mild essential hypertension. PC groups were increased in MS subjects and in adult obese subjects. In MS subjects the PC groups were not influenced by the presence of diabetes mellitus and in adult obese subjects were not influenced by the obesity degree. In OSAS subjects only those with AHI > 30 showed an increase of PC groups. PC groups increased in CKD subjects undergoing conservative treatment and haemodialysis therapy. In dialyzed subjects, after a standard dialysis session, there was a marked increase in PC groups. In juvenile myocardial infarction PC groups were higher than in controls; there was no difference between STEMI and NSTEMI and their concentration was unaffected by the number of cardiovascular risk factors or stenosed coronary vessels.

Employing Neural Network Methods to Label Sleep EEG Micro-Arousals in Obstructive Sleep Apnea Syndrome

Well-designed studies are essential to screen suspected cases of Obstructive Sleep Apnea Syndrome (OSAS) using the widely-referenced questionnaires and then to confirm the diagnosis by means of full Polysomnography (PSG), and finally to assess various variables of treatment efficacy and safety. Defining the severity index of OSAS based on the Apnea-Hypopnea Index (AHI), sleep marco- and micro-structural features (i.e. hypnogram and cyclic alternating patterns or CAPs), and neurocognitive functions would help better explain the treatment outcome. Using the neural network models on sleep data in OSAS sufferers is potentially expected to help the above goals. Determination of neurocognitive impairments in OSAS subjects in relation with disease severity indices and subsequent changes in microstructural changes (i.e. CAPs) in sleep Electroencephalography (EEG), would therefore be useful in defining individualized care and cognitive rehabilitation plans. The present methodology paper has attempted to address the above hypothesis in a clinical population from a hospital-based sleep disorders laboratory.

Emotional Intelligence in Children with Severe Sleep-Related Breathing Disorders.

Background Obstructive sleep apnea syndrome (OSAS) affects up to 4% of a pediatric population, with many comorbidities in the medium-long term. Functional alterations in the prefrontal cortex (PFC) may explain why OSAS impacts aspects such as executive functions, memory, motor control, attention, visual-spatial skills, learning, and mood regulation. Emotional intelligence (EI) is a complex neuropsychological function that could be impaired in many clinical conditions. Purpose The aim of the study is to evaluate the difference in emotional intelligence skills among children with OSAS and healthy subjects (nOSAS). Methods 129 children (72 males; mean age 7.64 ± 1.98 years) affected by OSAS were compared to 264 non-OSAS (nOSAS) children (138 males; mean age 7.98 ± 2.13) similar for gender, age, and socioeconomic status. In order to assess the emotional quotient, the Bar-On Emotional Quotient Inventory: Youth Version (EQ-i:YV) was used. Results The comparison for means and standard deviation between OSAS children and nOSAS children for EQ-i:YV scores showed significant differences for Interpersonal, Adaptability, and Stress Management scales and EQ Total score. Conclusions Our findings highlighted the role of intermittent hypoxia in the genesis of the effects of sleep-related respiratory disorders, which involves also aspects different from physical impairments.

Correlation of serum meteorin-like concentration with the presence and severity of obstructive sleep apnoea syndrome.

Objective Inflammatory processes that occur in subjects with obstructive sleep apnoea syndrome may contribute to progressive atherosclerosis and increased cardiovascular and cerebrovascular morbidity. Meteorin-like protein, which is also known as subfatin, is transcribed similarly to meteorin protein. Meteorin-like alleviates skeletal muscle inflammation. We aimed to investigate the serum meteorin-like status of obstructive sleep apnoea syndrome subjects and determine the potential link between serum meteorin-like concentration with the presence and severity of obstructive sleep apnoea syndrome. Methods The obstructive sleep apnoea syndrome group was composed of 207 obstructive sleep apnoea syndrome subjects diagnosed via polysomnography. A total of 106 healthy volunteers without clinical symptoms of obstructive sleep apnoea syndrome were recruited as the control group. Blood samples were obtained from all subjects to evaluate the serum meteorin-like concentrations via enzyme-linked immunosorbent assay method. Results Decreased serum meteorin-like concentration was found in obstructive sleep apnoea syndrome subjects compared with the controls. Serum meteorin-like concentration was associated with a reduced OR for having obstructive sleep apnoea syndrome (OR 0.97, 95% CI 0.961 to 0.98; P &lt; 0.001). Severe obstructive sleep apnoea syndrome subjects showed significantly lower meteorin-like concentration compared with mild and moderate cases. Moderate subjects exhibited decreased serum meteorin-like concentration compared with mild cases. Pearson correlation analysis revealed that serum meteorin-like concentration was negatively correlated with obstructive sleep apnoea syndrome severity. Serum meteorin-like concentration negatively correlated with body mass index, low-density lipoprotein cholesterol, apnoea–hypopnea index, number of arousals, hypopnoea and apnoea in subjects with obstructive sleep apnoea syndrome. Conclusion Serum meteorin-like concentration is inversely correlated with the presence and severity of obstructive sleep apnoea syndrome.

Proteomic biomarkers of cognitive impairment in obstructive sleep apnea syndrome.

There are currently no biomarkers that are associated with cognitive impairment (CI) in patients with obstructive sleep apnea syndrome (OSAS). This pilot study performed an exploratory plasma proteomic analysis to discover potential biomarkers and explore proteomic pathways that differentiate OSAS subjects with and without CI. Participants were selected from a cohort of women within 5years of menopause not on hormone replacement therapy between the ages of 45-60years. The Berlin questionnaire was used to select OSAS participants who then completed the MCFSI (Mail-In Cognitive Function Screening Instrument) to measure cognition. Six subjects with the highest MCFSI scores (≥ 5 denoting CI) were compared to six with normal scores. Proteomic analysis was done by Myriad RBM using a targeted ELISA for 254 serum proteins. Pathway analysis of differentially expressed proteins was performed using STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) software. Distinct proteomic signatures were seen in OSAS subjects with CI as compared to those without CI. Proteins including insulin, prostasin, angiopoietin-1, plasminogen activator inhibitor 1, and interleukin-1 beta were overexpressed in OSAS subjects with CI. Proteins underexpressed in CI participants included cathepsin B, ceruloplasmin, and adiponectin. Pathway analysis revealed prominence of insulin-regulated vascular disease biomarkers. Proteomic biomarkers in participants with cognitive impairment suggest roles for insulin, and vascular signaling pathways, some of which are similar to findings in Alzheimer's disease. A better understanding of the pathogenic mechanisms of CI in OSAS will help focus clinical trials needed in this patient population.

Does the neutrophil-to-lymphocyte ratio have any importance between subjects with obstructive sleep apnea syndrome with obesity and without obesity?

An increase in the incidence of OSAS (obstructive sleep apnoea syndrome) has been seen due to the reported association between OSAS and obesity. Subjects are predisposed to cardiovascular disease due to systemic inflammation caused by the interactions between obesity and OSA. Inflammatory markers could be used to predict the degree of systemic inflammation, which could be a prognostic factor for future adverse events such as metabolic risks. One marker that has recently started being used as an indicator of systemic inflammation is neutrophil-to-lymphocyte ratio (NLR). The aim is to evaluate NLR, which is a easily measured parameter of systemic inflammation in OSAS subjects with and without obesity. 155 subjects were assigned to four different groups according to their body mass indices. Comparisons of white blood cell, neutrophil, lymphocyte, NLR values and anthropometric measurements were done for each group. The NLR and neutrophil counts of group 4 were statistically significant and higher than those of groups 1, 2 and 3. The lymphocyte counts of group 4 were the lowest amongst all groups, these values were lower than the lymphocyte counts of groups 1, 2 and 3 with statistically significant differences (p< 001). A positive correlation was found between the body mass index and lymphocyte count values of obese OSAS subjects (r= 0.027, p= 353). The NLR ratio was found to be increasing by obesity grade and reveals that the associated inflammatory response also increases. The NLR ratio might be used as an inflammatory marker in obese OSAS subjects.

Nocturnal blood pressure fluctuation and associated influential factors in severe obstructive sleep apnea patients with hypertension

Obstructive sleep apnea syndrome (OSAS) can induce dramatic blood pressure (BP) fluctuations during sleep and it can be associated with hypertension. We investigated the properties and associated influential factors of BP fluctuation in severe OSAS with and without hypertension. Two hundred one severe OSAS subjects were divided into hypertensive and normotensive groups. BP was continuously monitored via measurement of pulse transmit time (PTT). The value of apnea-related systolic BP elevation (ΔSBP) was used to reflect the amplitude of BP fluctuation, and the SBP index (the number of ΔSBP > 10mmHg per hour of sleep time) was used to stand for the frequency of significant BP fluctuations. Compared with the normotensive group, △SBP and SBP index were higher in the hypertensive group (13.8 ± 4.4mmHg vs 10.9 ± 3.1mmHg; 44.8 ± 21.3 events/h vs 26.8 ± 15.8 events/h, all p < 0.001). Multiple regression analysis showed that percentage of sleep time with oxygen saturation < 90% (TST90) and SBP index correlated more with mean level of awakeness and sleep SBP than with apnea-hypopnea index (AHI). Analysis of all apnea events demonstrated that △SBP and the frequency of BP fluctuations were more remarkable following hypoxia than following arousal; △SBP correlated more with oxygen desaturation degree (r = 0.388, p < 0.01) and minimal SpO2 (r = 0.392, p < 0.01) than with apnea length and desaturation duration. In severe OSAS, nocturnal and awake BP levels are associated more with the nocturnal hypoxic duration and BP fluctuation than with AHI. Nocturnal BP fluctuation can be induced by both hypoxia and arousal, and especially by hypoxia. NCT02876471.

Antero-cervical thermophysiological characterization of obstructive sleep apnea patients.

Obstructive sleep apnea syndrome (OSAS) is characterized by upper airway inflammation. The aim of this study was to characterize thermal profile of the antero-cervical region in OSAS patients through medical thermal imaging and to compare the respective subjects with non-OSAS individuals. Image capture followed the Glamorgan Protocol. A dynamic thermographic examination of the anterior cervical region (at baseline and after a cold stimulus) was conducted in 26 patients diagnosed with overnight polysomnography (PSG). PSG results stratified the subjects into OSAS and non-OSAS groups and their thermograms were compared. Eleven non-OSAS and 15 OSAS subjects were evaluated. Antero-cervical right side (RS) temperature was higher in OSAS group at baseline (p = 0.014). Right side index (RSI) temperature-the difference between RS and submental region, considered as control-was lower in OSAS subjects at baseline (p = 0.020) and 10min after the cold stimuli was applied (p = 0.008), indicating higher absolute temperatures in this group. Left side index (LSI) was also lower at 10min in OSAS group (p = 0.021). Statistical correlation was found between apnea-hypopnea index and RS at baseline (r = 0.424, p = 0.031) and at 10min (r = 0.403, p = 0.041) and RSI at baseline (r = - 0.458, p = 0.019) and 10min after cold provocation was applied (r = - 0.435, p = 0.025). OSAS patients have shown higher antero-cervical temperatures compared with non-OSAS counterparts and temperature was associated with severity of the condition. Medical thermography may be a suitable tool in the setting of OSAS suspicion.

Gamma-glutamyl transferase activity as a predictive marker for severity of obstructive sleep apnea syndrome and concomitant hypertension.

Chronic intermittent hypia, inflammation and oxidative stress are involved in resultant obstructive sleep apnea syndrome (OSAS), which may affect numerous regulatory mechanisms that play a role in the regulation of blood pressure. Gamma-glutamyl transferase (GGT) is a novel marker in the prediction of cardiovascular risk. The objective of this study was to investigate the correlation of serum levels of GGT with hypertension and the degree of the upper airway obstruction in subjects with OSAS. A total of 270 subjects that met the inclusion criteria were enrolled in the study. The subjects were divided into four separate groups according to the apnea-hypopnea index (AHI) scores as the control group (AHI<5), mild OSAS group (AHI 5-15), moderate OSAS group (AHI 16-30) and severe OSAS group (AHI >30). A further classification of the OSAS subjects was made in two groups based on the presence of hypertension. The study included 43 control individuals and 59 subjects with mild, 54 subjects with moderate and 114 subjects with severe OSAS. The serum levels of GGT were found to be significantly correlated with OSAS severity (control group: 18±3.3, mild OSAS: 23.6±7.3, moderate OSAS: 26.4±7.5 and severe OSAS: 39.8±12). Serum levels of GGT were found to be significantly higher in OSAS subjects with concomitant hypertension than in the group without associated hypertension (P<.05). The results showed that the adjusted mean GGT under OSA without hypertension (Madj =28.76, SE=0.71) was significantly lower than in cases with OSA with hypertension (Madj =42.79, SE=1.19). The present study indicated a strong correlation between high serum levels of GGT and concomitant hypertension in subjects with obstructive sleep apnea. This biomarker may be helpful in grading the severity of obstructive sleep apnea and correlated with hypertension in this population.

Sleep microstructure dynamics and neurocognitive performance in obstructive sleep apnea syndrome patients.

The present study examined the relationship between the increment in cyclic alternating patterns (CAPs) in sleep electroencephalography and neurocognitive decline in obstructive Sleep Apnea Syndrome (OSAS) patients through source localization of the phase-A of CAPs. All-night polysomnographic recordings of 10 OSAS patients and 4 control subjects along with their cognitive profile using the Addenbrooke's Cognitive Examination (ACE) test were acquired. The neuropsychological assessment involved five key domains including attention and orientation, verbal fluency, memory, language and visuo-spatial skills. The standardized low-resolution brain electromagnetic tomography (sLORETA) tool was used to source-localize the phase-A of CAPs in sleep EEG aiming to investigate the correlation between CAP phase-A and cognitive functions. Our findings suggested a significant increase in CAP rates among OSAS subjects versus control subjects. Moreover, sLORETA revealed that CAP phase-A is mostly activated in frontoparietal cortices. As CAP rate increases, the activity of phase-A in such areas is dramatically enhanced leading to arousal instability, lower sleep efficiency and a possibly impaired cortical capacity to consolidate cognitive inputs in frontal and parietal areas during sleep. As such, cognitive domains including verbal fluency, memory and visuo-spatial skills which predominantly relate to frontoparietal areas tend to be affected. Based on our findings, CAP activity may possibly be considered as a predictor of cognitive decline among OSAS patients.

État des lieux des connaissances et attitudes des médecins de Brazzaville sur le syndrome d’apnée obstructive du sommeil

Obstructive sleep apnea syndrome (OSAS) is the leading sleep-related breathing disorder. Its complications and its repercussions on the quality of life of patients make the OSAS a real public health problem. The objective of this study is to both asses physicians knowledge of OSAS and describe their attitudes towards suspect subjects in Brazzaville. This was a cross-sectional study of 230 doctors practicing in various hospitals in the city of Brazzaville. The data collection was done by a self-questionnaire developed after a bibliographic analysis on the OSAS. The questionnaire was completed without recourse to a source of information. Our sample consisted of 141 (70.50%) general practitioners and 59 (29.50%) specialist physicians. The average of the knowledge score was 9.34 points±3.03 points. The general level of physician knowledge about SAS was good in 2% of cases, average in 44% of cases and low in 54% of cases. The level of knowledge was related to the number of times the OSAS diagnosis was mentioned by the physician in his practice (P<0.001), to the doctor's grade (P=0.003); to his university of origin and to the quantity of sources of information. When faced with suspects OSAS subjects, the doctor, the doctor directed the patient in 62% of the cases in ENT and in 49% in the pulmonology. The knowledge of the doctors on the OSAS are weak; this results in poor management of this pathology in the Congo.

A NONINVASIVE METHOD TO EVALUATE THE DEGREE OF UPPER AIRWAY STENOSIS

Purpose: This paper presented a new approach to noninvasively evaluate the upper airway stenosis for obstructive sleep apnea syndrome (OSAS) patients. Methods: In the proposed method, thoracic and abdominal movements were selected to calculate the respiratory movement (RM) and to indicate the change of lung volume. Due to the cumulative effect of thermal sensor, the oronasal-thermistor signal (T_flow) is applied to estimate the air mass change in lung. Based on the mathematical relationship, the “RM–T_flow curves”, drawn by RM and T_flow, together with the correlation coefficients ([Formula: see text] were used to analyze the upper airway stenosis. Results: This method was verified through portable monitoring (PM) based experiments, and numerical analysis of the polysomnography (PSG) data from 20 OSAS patients and 15 non-OSAS controls. Our results indicate the [Formula: see text] values decrease with the narrowing of the upper airway. At each sleep stage, the [Formula: see text] mean values of OSAS subjects are significantly ([Formula: see text]) smaller than those of the controls. These facts demonstrate that the [Formula: see text] value can be used to quantify the upper airway stenosis and the analysis of “RM–T_flow curves” is an efficient way to assess upper airway condition associated with the breathing phase. Conclusions: As this method can be used in spontaneous sleep and home sleep testing, we believe it will benefit the popularity of the diagnosis and evaluation of OSAS.

Integrating postural and vestibular dimensions to depict impairment in moderate-to-severe obstructive sleep apnea syndrome patients.

Vestibular dysfunction was linked to moderate-to-severe obstructive sleep apnea syndrome (OSAS) patients in literature. However, due to a lack of knowledge among valid and recent implementations conceived to study postural control on static posturography (SP) and vestibulo-ocular reflex (VOR) gain under physiological conditions (video Head Impulse Test; vHIT), the aim of this work was to integrate (i) VOR changes via vHIT implementation, (ii) postural arrangement by studying both classical parameters and frequency spectra (PS) and (iii) correlation between these findings, polygraphic (PG) and subjective scores along Dizziness Handicap Inventory (DHI) and Epworth Sleepiness Scale (ESS). Thus, 32 moderate-to-severe OSAS patients and 32 healthy subjects - studied by using PG, DHI and ESS - underwent vHIT and SP posturographic assessment. Analysis of variance was performed to disclose between-group effects and correlation analysis was implemented between otoneurological, PG, DHI and ESS values. OSAS group demonstrated a significant decay of VOR gain and an increase in both frequency spectra PS values, especially within the low-frequency interval, and in classical posturographic SP parameters. Further, positive and negative correlations between mean SaO2 and gain and low frequency interval spectra PS were found, respectively. Strengthening previous hypothesis related to brainstem chronic hypoxemia phenomena affecting vestibular network, implementation of these data could generate future attentions (i) for screening under physiological conditions postural and vestibular detriments in OSAS subjects, especially exposed at risk settings, and (ii) among PG parameters, such as mean SaO2 , to propose further reliable tools in monitoring postural and vestibular decay in these patients demonstrating PG parameters detriments.

The Effects of Obstructive Sleep Apnea Syndrome on the Dentate Gyrus and Learning and Memory in Children.

Obstructive sleep apnea syndrome (OSAS) is associated with intermittent hypoxia and sleep loss. In children, impairments of cognitive function are important manifestations, but the underlying pathology is unknown. We hypothesized that OSAS would affect the dentate gyrus, a hippocampal subdivision essential to neurogenesis and cognition, and that this impact would further affect cognitive function in children. In children with OSAS (n = 11) and control subjects (n = 12; age and sex matched), we performed diffusion tensor imaging and structural MRI, polysomnography, and neuropsychological assessments. We found that OSAS was associated with decreased mean diffusivity of the left dentate gyrus (p = 0.002; false discovery rate corrected; adjusting for sex, age, and body mass index), showing a large effect size (partial η2 = 0.491), but not with any other structural measures across the brain. Decreased dentate gyrus mean diffusivity correlated with a higher apnea hypopnea index (Spearman's r = -0.50, p = 0.008) and a greater arousal index (r = -0.44, p = 0.017). OSAS did not significantly affect neuropsychological measures (p values >0.5); however, a lower verbal learning score correlated with lower dentate gyrus mean diffusivity (r = 0.54, p = 0.004). Path analysis demonstrated that dentate gyrus mean diffusivity mediates the impact of OSAS on verbal learning capacity. Finally, the diagnostic accuracy of a regression model based on dentate gyrus mean diffusivity reached 85.8% (cross validated). This study demonstrates a likely pathway of effects of OSAS on neurocognitive function in children, as well as potential utility of the dentate gyrus mean diffusivity as an early marker of brain pathology in children with OSAS.SIGNIFICANCE STATEMENT In this study we investigate the relationships between dentate gyrus structure, hippocampus-dependent cognition, and obstructive sleep apnea syndrome (OSAS). We demonstrate lower mean diffusivity of the dentate gyrus in children with OSAS, which correlates with a lower verbal learning and memory score. This study provides new evidence of disrupted microstructure of the dentate gyrus in children with OSAS that may help explain some of the neurocognitive deficits described in these children.

Adenotonsillectomy can decrease enuresis and sympathetic nervous activity in children with obstructive sleep apnea syndrome

The nocturnal intermittent hypoxia caused by obstructive sleep apnea syndrome (OSAS) can provoke the sympathetic nervous activity (SNA). Salivary alpha-amylase (sAA) is a sensitive, non-invasive biomarker for reflecting the SNA, and a useful marker for pediatric OSAS subjects. Adenotonsillar hypertrophy (ATH) is the most commonly identified risk factor in OSAS childhood, therefore, several studies showed that the adenotonsillectomy (T&A) may alleviate nocturnal enuresis (NE) in children with OSAS. The present study was to investigate the effect of T&A on NE, the change of sAA value in ATH and OSAS children, with/without NE, and with/without the operation. 37 children (Group A) were admitted for ATH and NE. The saliva samples were taken before and after polysomnography for the measure of sAA. After the T&A, the children were followed-up for 1 year. 35 OSAS children with NE but no T&A were as a NE watchful-waiting group (Group B), 32 subjects without OSAS or NE were as non-OSAS control (Group C), 42 cases who underwent T&A but did not have NE were admitted to evaluate the SNA (Group D). Follow-up included evaluations for NE, sAA and urinary catecholamine after the T&A or at the equivalent time points. The observational results in the present study showed a significant rate of the disappearance of NE 1 month after the T&A and had an almost complete resolution 1 year later. OSAS may irritate oxidative stress and increase SNA in pediatric subjects, which reflected by increased levels of sAA and urinary catecholamine, while the T&A can decrease enuresis and the SNA in children with OSAS (Figure). Little research has previously focused on the relationship between childhood OSAS and the SNA. No data are currently available regarding comparisons of sAA levels before and after the T&A in children with OSAS and enuresis. Our findings in this present study showed that there was a resolution or decrease in enuresis events and drops in sAA levels following T&A, which were consistent with earlier study. However, there was no significant difference in the urinary catecholamine levels was found between OSAS groups with or without NE. Furthermore, there was no correlation between the urinary catecholamine and polysomnography parameters. T&A has a favorable therapeutic effect on NE and may decrease SNA in children with OSAS. sAA might be associated with instability of ANS by OSAS and have a consistent relationship with the apnea-hypopnea index. Our studying aims had been met.

Erythrocyte deformability, plasma lipid peroxidation and plasma protein oxidation in a group of OSAS subjects.

Considering that obstructive sleep apnea syndrome (OSAS) is usually associated with endothelial dysfunction, atherosclerosis and cardiovascular disorders, our aim was to examine the erythrocyte deformability and the oxidative status in a group of OSAS subjects. We consecutively enrolled 48 subjects with OSAS defined after a 1-night cardiorespiratory sleep study, subsequently subdivided according to the apnea/hypopnea index (AHI) value in two subgroups: Low (L = 21 subjects with AHI<30) and High (H = 27 subjects with AHI>30). We evaluated the erythrocyte deformability, expressed as elongation index (EI) and the parameters of the oxidative status, such as lipid peroxidation (expressed as thiobarbituric acid-reactive substances - TBARS) and protein oxidation (measured as carbonyl groups - PC). In the entire group and in the two subgroups of OSAS subjects we found a decreased erytrocyte deformability at all shear stresses, not correlated with the plasmatic oxidative stress nor with the polysomnographic parameters. Lipid peroxidation was increased in the whole group and in the H subgroup of OSAS while protein oxidation showed a different trend. As in OSAS the osmotic fragility and the metabolism of the red cells seem to be not impaired, the oxidative damage to the red cell membrane proteins might be responsible for the reduced erythrocyte deformability. This rheological alteration, in addition to the increase in whole blood and plasma viscosity and to the erythrocyte hyperaggregation, could influence the microcircolatory profile in OSAS subjects.