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Excessive daytime sleepiness (EDS) is a common complaint in the general population and is associated with cardiovascular disease and increased mortality. We aimed to investigate whether sleep duration is related to excessive daytime sleepiness in the general population, both in itself and in combination with other factors. We performed a cross-sectional analysis in the population-based Swedish CArdioPulmonary bioImage Study (SCAPIS) cohort (n = 27,976; 14,436 females; aged 50-64 years) to assess how sleep-related factors along with anthropometric, lifestyle, socioeconomic factors as well as somatic disease and psychological distress, were related with EDS assessed by the Epworth sleepiness scale (ESS). Analyses were performed using logistic regression modelling with EDS defined by an ESS score of ≥11 as the main outcome. Both short and long sleep duration were related to EDS with increasing ORs for decreasing sleep duration (7 h vs. reference (8 h): OR 1.2, 95% CI 1.02-1.3 to ≤4 h: 1.9; 1.4-2.5). In addition to sleep-related factors such as insomnia (1.3; 1.2-1.4), poor sleep quality (1.2; 1.04-1.4), snoring (1.5; 1.4-1.6), and nocturnal gastro-oesophageal reflux (1.5; 1.21-1.8), psychological distress showed a strong association with EDS. This included sadness/depression (1.2; 1.1-1.3), stress (some stress: 1.4; 1.1-1.7 to constant stress over 5 years: 1.7; 1.3-2.2), and self-rated "control in life" (lowest quartile: 1.7; 1.6-2.0). Daytime sleepiness is multifactorial and associated with both sleep duration and sleep quality. Strong associations were also established with factors related to psychological distress. Further research may investigate interventions targeting both sleep and psychological health to reduce daytime sleepiness at the societal level., (© 2025 The Author(s). Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Obstructive sleep apnea diagnosis is based on the manual scoring of respiratory events. The agreement in the manual scoring of the respiratory events lacks an in-depth investigation as most of the previous studies reported only the apnea-hypopnea index or overall agreement, and not temporal, second-by-second or event subtype agreement. We hypothesized the temporal and subtype agreement to be low because the event duration or subtypes are not generally considered in current clinical practice. The data comprised 50 polysomnography recordings scored by 10 experts. The respiratory event agreement between the scorers was calculated using kappa statistics in a second-by-second manner. Obstructive sleep apnea severity categories (no obstructive sleep apnea/mild/moderate/severe) were compared between scorers. The Fleiss' kappa value for binary (event/no event) respiratory event scorings was 0.32. When calculated separately within N1, N2, N3 and R, the Fleiss' kappa values were 0.12, 0.23, 0.22 and 0.23, respectively. Binary analysis conducted separately for the event subtypes showed the highest Fleiss' kappa for hypopneas to be 0.26. In 34% of the participants, the obstructive sleep apnea severity category was the same regardless of the scorer, whereas in the rest of the participants the category changed depending on the scorer. Our findings indicate that the agreement of manual scoring of respiratory events depends on the event type and sleep stage. The manual scoring has discrepancies, and these differences affect the obstructive sleep apnea diagnosis. This is an alarming finding, as ultimately these differences in the scorings affect treatment decisions., (© 2024 The Author(s). Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

In-laboratory polysomnography, the gold-standard for diagnosing sleep disorders, is resource-demanding and not conducive to multiple night evaluations. Ambulatory polysomnography, especially when self-applied, could be a viable alternative. This study aimed to assess the feasibility and reliability of self-applied polysomnography over three consecutive nights in untrained participants, assessing: technical success rate; comparing sleep diagnostic variables from single and multiple nights; and evaluating participants' subjective experience. Data were collected from 78 participants (55.1% females) invited to test a self-applicable polysomnography device for three consecutive nights at home. The technical success rate for valid sleep recordings was 82.5% out of 234 planned study nights, with 87.2% of participants obtaining at least two valid nights. Misclassification of obstructive sleep apnea severity was higher in participants with mild OSA (21.4%) compared with those with moderate-to-severe obstructive sleep apnea or no obstructive sleep apnea. Sleep efficiency and wake after sleep onset showed improvement from Night 1 to Night 3 (p < 0.001), and the mean polysomnography set-up time decreased significantly over this period. Participants reported moderate-to-high satisfaction with the device (System Usability Scale score 71.2 ± 12.4). The findings suggest that self-applied polysomnography is a feasible diagnostic method for untrained individuals at risk for sleep disorders, and that multiple night assessments can improve diagnostic precision for mild obstructive sleep apnea cases., (© 2024 The Author(s). Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

We recruited 5,970 hypertensive patients with obstructive sleep apnea (OSA) on current antihypertensive treatment from the European Sleep Apnea Database (ESADA) cohort. The group was subdivided into those receiving monotherapy (n = 3,594) and those receiving dual combined therapy (n = 2,376). We studied how major OSA confounders like age, gender, and body mass index as well as the degree of sleep apnea modified office systolic and diastolic blood pressure. Beta-blockers alone or in combination with a diuretic were compared with other antihypertensive drug classes. Monotherapy with beta-blocker was associated with lower systolic blood pressure, particularly in non-obese middle-aged males with hypertension. Conversely, the combination of a beta-blocker and a diuretic was associated with lower systolic and diastolic blood pressure in hypertensive patients with moderate-severe OSA. Systolic blood pressure was better controlled in female patients using this combined treatment. Our cross-sectional data suggest that specific clinical characteristics and type of antihypertensive medication influence the degree of blood pressure control in hypertensive OSA patients. Controlled trials are warranted., (© 2022 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Excessive daytime sleepiness (EDS) is a hallmark symptom in obstructive sleep apnea (OSA). It is commonly eliminated by obstructive sleep apnea therapy and constitutes a major treatment indication. This study aimed to identify determinants of excessive daytime sleepiness by the Epworth Sleepiness Scale (ESS) scores in the large, representative national obstructive sleep apnea patient cohort of the Swedish Sleep Apnea Registry (SESAR, www.sesar.se). Data from 34,684 patients with obstructive sleep apnea recruited at 23 sites (33% females, mean age 55.7 ± 13.7 years, BMI 30.2 ± 6.3 kg/m 2 , AHI 29.1 ± 22.3, and ODI 24.9 ± 21.4 events/h) had a mean ESS score in the mild to moderate excessive daytime sleepiness range (9.7 ± 4.9). The proportion of patients with excessive daytime sleepiness was 41.4% in men and 44.6% in women. Independent predictors of excessive daytime sleepiness included gender, age, and hypoxic markers (high ODI and low mean saturation). Univariate and multivariate analyses were used to identify significant predictors for the ESS score and for excessive daytime sleepiness (ESS ≥10) amongst anthropometric factors, sleep apnea frequency (apnea-hypopnea index (AHI)), markers of intermittent hypoxia (oxygen desaturation index (ODI), mean saturation (mSaO 2 )), as well as prevalent comorbidities. Depression was associated with higher ESS scores and hypertension/atrial fibrillation with lower scores. The oxygen desaturation index provided a stronger predictor of excessive daytime sleepiness than the apnea-hypopnea index. The severity of obstructive sleep apnea, captured as the apnea-hypopnea index, was only weakly associated with daytime sleepiness in this representative obstructive sleep apnea patient cohort. Age had different effects in men and women.The impact of obstructive sleep apnea in a wider patient related perspective needs to be determined after the inclusion of factors other than the apnea-hypopnea index., (© 2022 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Obstructive sleep apnea is linked to severe health consequences such as hypertension, daytime sleepiness, and cardiovascular disease. Nearly a billion people are estimated to have obstructive sleep apnea with a substantial economic burden. However, the current diagnostic parameter of obstructive sleep apnea, the apnea-hypopnea index, correlates poorly with related comorbidities and symptoms. Obstructive sleep apnea severity is measured by counting respiratory events, while other physiologically relevant consequences are ignored. Furthermore, as the clinical methods for analysing polysomnographic signals are outdated, laborious, and expensive, most patients with obstructive sleep apnea remain undiagnosed. Therefore, more personalised diagnostic approaches are urgently needed. The Sleep Revolution, funded by the European Union's Horizon 2020 Research and Innovation Programme, aims to tackle these shortcomings by developing machine learning tools to better estimate obstructive sleep apnea severity and phenotypes. This allows for improved personalised treatment options, including increased patient participation. Also, implementing these tools will alleviate the costs and increase the availability of sleep studies by decreasing manual scoring labour. Finally, the project aims to design a digital platform that functions as a bridge between researchers, patients, and clinicians, with an electronic sleep diary, objective cognitive tests, and questionnaires in a mobile application. These ambitious goals will be achieved through extensive collaboration between 39 centres, including expertise from sleep medicine, computer science, and industry and by utilising tens of thousands of retrospectively and prospectively collected sleep recordings. With the commitment of the European Sleep Research Society and Assembly of National Sleep Societies, the Sleep Revolution has the unique possibility to create new standardised guidelines for sleep medicine., (© 2022 European Sleep Research Society.)

Sleep is controlled by a circadian rhythmicity, via a reduction of arousal-promoting neuromodulatory activity, and by accumulation of somnogenic factors in the interstitial fluid of the brain. Recent experiments in mice suggest that a reduced neuronal excitability caused by a reduced concentration of potassium in the brain, concomitant with an increased concentration of calcium and magnesium, constitutes an important mediator of sleep. In the present study, we examined whether such changes in ion concentrations could be detected in the cerebrospinal fluid of healthy humans. Each subject underwent cerebrospinal fluid collection at three occasions in a randomized order: at 15:00 hours-17:00 hours during waking, at 06:00 hours-07:00 hours immediately following 1 night of sleep, and at 06:00 hours-07:00 hours following 1 night of sleep deprivation. When compared with wakefulness, both sleep and sleep deprivation produced the same effect of a small (0.1 mm, about 3%), but robust and highly significant, reduction in potassium concentration. Calcium and magnesium concentrations were unchanged. Our results support a circadian modulation of neuronal excitability in the brain mediated via changes of the interstitial potassium concentration., (© 2021 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Recent evidence supports the use of pulse wave analysis during sleep for assessing functional aspects of the cardiovascular system. The current study compared the influence of pulse wave and sleep study-derived parameters on cardiovascular risk assessment. In a multi-centric study design, 358 sleep apnea patients (age 55 ± 13 years, 64% male, body mass index 30 ± 6 kg m -2 , apnea-hypopnea index 13 [5-26] events per hr) underwent a standard overnight sleep recording. A novel cardiac risk index was computed based on pulse wave signals derived from pulse oximetry, reflecting vascular stiffness, cardiac variability, vascular autonomic tone and nocturnal hypoxia. Cardiovascular risk was determined using the ESC/ESH cardiovascular risk matrix, and categorized to high/low added cardiovascular risk. Comparisons between cardiac risk index and sleep parameters were performed for cardiovascular risk prediction. Apnea-hypopnea index, oxygen desaturation index and cardiac risk index were associated with high cardiovascular risk after adjustment for confounders (p = .002, .001, < .001, respectively). In a nested reference model consisting of age, gender and body mass index, adding cardiac risk index but not apnea-hypopnea index or oxygen desaturation index significantly increased the area under the receiver operating characteristic curve (p = .012, .22 and .16, respectively). In a direct comparison of oxygen desaturation index and cardiac risk index, only the novel risk index had an independent effect on cardiovascular risk prediction (p CRI  < .001, p ODI  = .71). These results emphasize the association between nocturnal pulse wave and overall cardiovascular risk determined by an established risk matrix. Thus, pulse wave analysis during sleep provides a powerful approach for cardiovascular risk assessment in addition to conventional sleep study parameters., (© 2021 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Patients with obstructive sleep apnea (OSA) are at increased risk of developing metabolic disease such as diabetes. The effects of positive airway pressure on glycemic control are contradictory. We therefore evaluated the change in glycated hemoglobin (HbA1c) in a large cohort of OSA patients after long-term treatment with positive airway pressure. HbA1c levels were assessed in a subsample of the European Sleep Apnea Database [n=1608] at baseline and at long-term follow up with positive airway pressure therapy (mean 378.9±423.0 days). In a regression analysis, treatment response was controlled for important confounders. Overall, HbA1c decreased from 5.98±1.01% to 5.93±0.98% (p=0.001). Patient subgroups with a more pronounced HbA1c response included patients with diabetes (-0.15±1.02, p=0.019), those with severe OSA baseline (-0.10±0.68, p=0.005), those with morbid obesity (-0.20±0.81, p<0.001). The strongest HbA1c reduction was observed in patients with a concomitant weight reduction >5 kilos (-0.38±0.99, p<0.001). In robust regression analysis, severe OSA (p=0.038) and morbid obesity (p=0.005) at baseline, and weight reduction >5 kilos (p<0.001) during follow up were independently associated with a reduction of HbA1c following PAP treatment. In contrast, PAP treatment alone without weight reduction was not associated with significant Hb1Ac reduction. In conclusion, positive airway pressure therapy is associated with HbA1c reduction in patients with severe OSA, in morbidly obese patients. and most obviously in those with significant weight lost during the follow-up. Our study underlines the importance to combine positive airway pressure use with adjustments in lifestyle to substantially modify metabolic complications in OSA., (© 2021 European Sleep Research Society.)

Whole blood carbonic anhydrase activity (CAa) is increased in patients with obstructive sleep apnea (OSA). Our study investigated the influence of positive airway pressure (PAP) or CA inhibitor acetazolamide (ACT) therapy on CAa, OSA and blood pressure. Thirty-three OSA patients (21 hypertensive, body mass index (BMI) 37 ± 7 kg/m 2 and apnea-hypopnea index (AHI) of 47 ± 31 events/hr) were followed-up after PAP treatment (compliance, 4.7 ± 1.5 hr/day; duration, median 6 [IQR 6,6] months) (Cohort A). A second OSA Cohort (B) contained nine hypertensive patients (BMI, 29 ± 4 kg/m 2 ; AHI, 39 ± 20 events/hr) with 2-week treatment of ACT, PAP or ACT + PAP in an open crossover study. CAa was assessed at baseline and at the end of each treatment period. In Cohort A, baseline CAa was higher in hypertensive, compared with normotensive, patients (1,033 ± 204 versus 861 ± 201 units, p = .028). PAP treatment reduced systolic/diastolic blood pressure but not CAa (-9 ± 11/-5 ± 7 mmHg and -20 ± 289 units, p < .001, <.001 and .70). In Cohort B, blood pressure was reduced in both ACT-treated groups (-10 ± 10/-5 ± 7 mmHg, p = .043 and .019; and -5 ± 5/-13 ± 13 mmHg, p < .001 and .009). AHI was reduced in both groups: ACT only, -17 ± 9 events/hr p = .001; and ACT + PAP, -39 ± 19 events/hr, p < .001. PAP did not change CAa (p = .98) but activity tended to decrease after ACT with or without PAP (p = .081 and .056). CAa is elevated in hypertensive OSA patients. Long-term PAP reduced blood pressure without affecting CAa. ACT reduced blood pressure and CAa. Increased CAa may constitute a physiological characteristic in OSA, contributing to comorbid hypertension., (© 2019 European Sleep Research Society.)

Obstructive sleep apnea (OSA) and asthma are often associated and several studies suggest a bidirectional relationship between asthma and OSA. This study analyzed the characteristics of patients with suspected OSA from the European Sleep Apnea Database according to presence/absence of physician-diagnosed asthma. Cross-sectional data in 16,236 patients (29.1% female) referred for suspected OSA were analyzed according to occurrence of physician-diagnosed asthma for anthropometrics, OSA severity and sleepiness. Sleep structure was assessed in patients studied by polysomnography (i.e. 48% of the sample). The prevalence of physician-diagnosed asthma in the entire cohort was 4.8% (7.9% in women, 3.7% in men, p < 0.0001), and decreased from subjects without OSA to patients with mild-moderate and severe OSA (p = 0.02). Obesity was highly prevalent in asthmatic women, whereas BMI distribution was similar in men with and without physician-diagnosed asthma. Distribution of OSA severity was similar in patients with and without physician-diagnosed asthma, and unaffected by treatment for asthma or gastroesophageal reflux. Asthma was associated with poor sleep quality and sleepiness. Physician-diagnosed asthma was less common in a sleep clinic population than expected from the results of studies in the general population. Obesity appears as the major factor raising suspicion of OSA in asthmatic women, whereas complaints of poor sleep quality were the likely reason for referral in asthmatic men., (© 2018 European Sleep Research Society.)

The effect of positive airway pressure treatment on weight and markers of central obesity in patients with obstructive sleep apnea remains unclear. We studied the change in body weight and anthropometric measures following positive airway pressure treatment in a large clinical cohort. Patients with obstructive sleep apnea with positive airway pressure treatment from the European Sleep Apnea Database registry (n = 1,415, 77% male, age 54 ± 11 [mean ± SD] years, body mass index 31.7 ± 6.4 kg/m 2 , apnea-hypopnea index 37 ± 24 n per hr, Epworth Sleepiness Scale 10.2 ± 5.0) were selected. Changes in body mass index and neck/waist/hip circumferences at baseline and at follow-up visit were analysed. Overall, body mass index (0.0 [95% confidence interval, -0.1 to 0.2] kg/m 2 ) and neck circumference (0.0 (95% confidence interval, -0.1 to 0.1] cm) were unchanged after positive airway pressure treatment compared with baseline (follow-up duration 1.1 ± 1.0 years and compliance 5.2 ± 2.1 hr per day). However, in non-obese (body mass index <30 kg/m 2 ) patients, positive airway pressure treatment was associated with an increased body mass index and waist circumference (0.4 [0.3-0.5] kg/m 2 and 0.8 [0.4-1.2] cm, respectively, all p < 0.05), and weight gain was significantly associated with higher positive airway pressure compliance and longer positive airway pressure treatment duration. In the obese subgroup, body mass index was reduced after positive airway pressure treatment (-0.3 [-0.5 to -0.1] kg/m 2 , p < 0.05) mainly in patients with a strong reduction in Epworth Sleepiness Scale. In conclusion, positive airway pressure therapy was not found to systematically change body mass index in the European Sleep Apnea Database cohort, but the response was heterogeneous. Our findings suggest that weight gain may be restricted to an obstructive sleep apnea phenotype without established obesity. Lifestyle intervention needs to be considered in both lean and obese patients with obstructive sleep apnea receiving positive airway pressure treatment., (© 2018 European Sleep Research Society.)

New European Union (EU) regulations state that untreated moderate to severe obstructive sleep apnea (OSA) coincident with excessive daytime sleepiness (EDS) constitutes a medical disorder leading to unfitness to drive. However, fitness to drive can be re-established by successful treatment of OSA and EDS. The aim of the current study was to compare patients undergoing the certification process with those of an unselected OSA patient cohort. The study compared consecutive patients in the certification group (n = 132) with a representative group of OSA patients with a current driving license and an Apnea Hypopnea Index (AHI) ≥ 15 n/h (n = 790). The adherence to positive airway pressure (PAP) therapy and the change in EDS (Epworth Sleepiness Scale [ESS] score) with treatment were analysed. Patient characteristics and severity of sleep apnea did not differ significantly between groups (certification/reference group: BMI 30 ± 5/31 ± 5 kg/m 2 , AHI 33 ± 20/36 ± 20 n/hr, ESS 12 ± 6/11 ± 5). However, the certification group was oversampled with elderly drivers (70-85 years: 22% vs. 9%, p = 0.001). PAP compliance was higher in the certification group than in the reference group (PAP use ≥ 4 hr/night in 96% vs. 53%, p = 0.001) and mean ESS reduction was -8.0 (-8.9 - -7.1) versus -4.0 (-4.4 - -3.5), respectively (p < 0.001). Patients attending the fitness to drive evaluation reported almost complete adherence to continuous positive airway pressure (CPAP) and elimination of EDS symptoms. Besides possible baseline differences, this strong response may be explained by factors such as a selection process of elderly patients, a self-rating component in the assessment of the treatment response and the threat of a driving license suspension. Our data suggest that an improved certification process with objective rather than subjective components, along with a reduced selection bias, is warranted., (© 2018 European Sleep Research Society.)

Sleep bruxism bears several similarities to restless legs syndrome, and a link to changes in central dopamine activity has been considered in both conditions. The dopamine agonist pramipexole is currently indicated for the symptomatic treatment of restless legs. The effect of pramipexole on sleep bruxism was investigated in subjects with 'probable bruxism' recruited at the Orofacial Pain Clinic. Thirteen patients underwent polysomnographic recordings, including bilateral masseter electromyographic activity. Following habituation to the recording equipment, a baseline registration was used to confirm bruxism [total episodes per hour, mean 11.3 (6.3)]. Following randomisation, subjects received no treatment or pramipexole titrated from 0.09 to 0.54 mg, o.d., for 3 weeks according to a crossover procedure. A polysomnographic-electromyographic registration was performed at the end of each period. Pramipexole was associated with more frequent awakenings and a reduction in rapid eye movement sleep (both P ≤ 0.02). Sleep apnea decreased marginally after pramipexole (apnea-hypopnea index 17.1 compared with control 21.5, P ≤ 0.05). The number of bruxism episodes, phasic, tonic and mixed per hour, remained unchanged after pramipexole [total episodes per hour 12.7 (8.5) and 9.8 (5.2) during pramipexole and control conditions, respectively]. It is concluded, from this pilot study, that sleep bruxism is not affected by the dopaminergic agent, pramipexole., (© 2016 European Sleep Research Society.)

The cross-sectional relationship of obstructive sleep apnea with moderate to severe chronic kidney disease, defined as an estimated glomerular filtration rate <60 mL min -1 ∙1.73 m -2 , was investigated in a large cohort of patients with suspected obstructive sleep apnea studied by nocturnal polysomnography or cardiorespiratory polygraphy. Data were obtained from the European Sleep Apnea Database, where information from unselected adult patients with suspected obstructive sleep apnea afferent to 26 European sleep centres had been prospectively collected. Both the Modification of Diet in Renal Disease and the Chronic Kidney Disease-Epidemiology Collaboration equations were used for the assessment of estimated glomerular filtration rate. The analysed sample included 7700 subjects, 71% male, aged 51.9 ± 12.5 years. Severe obstructive sleep apnea (apnea-hypopnea index ≥30) was found in 34% of subjects. The lowest nocturnal oxygen saturation was 81 ± 10.2%. Chronic kidney disease prevalence in the whole sample was 8.7% or 6.1%, according to the Modification of Diet in Renal Disease or the Chronic Kidney Disease-Epidemiology Collaboration equations, respectively. Subjects with lower estimated glomerular filtration rate were older, more obese, more often female, had worse obstructive sleep apnea and more co-morbidities (P < 0.001, each). With both equations, independent predictors of estimated glomerular filtration rate <60 were: chronic heart failure; female gender; systemic hypertension; older age; higher body mass index; and worse lowest nocturnal oxygen saturation. It was concluded that in obstructive sleep apnea, chronic kidney disease is largely predicted by co-morbidities and anthropometric characteristics. In addition, severe nocturnal hypoxaemia, even for only a small part of the night, may play an important role as a risk factor for kidney dysfunction., (© 2016 European Sleep Research Society.)

Polygraphy (PG) and polysomnography (PSG) are used in clinical settings in Europe for diagnosing obstructive sleep apnea (OSA), but their equivalence in unselected clinical cohorts is unknown. We hypothesized that the method would affect both diagnostic outcomes and disease severity stratification. Data from 11 049 patients in the multi-centre European Sleep Apnea Cohort (ESADA) with suspected OSA (male and female, aged 18-80 years) were used in two groups of patients to compare PG (n = 5745) and PSG (n = 5304). Respiratory events were scored using the 2007 American Association of Sleep Medicine (AASM) criteria. In subjects who underwent PSG, mean apnea-hypopnea index (AHI) using sleep time (AHIPSG 31.0 ± 26.1 h(-1) ) and total analysed time (TAT) (AHITAT 24.7 ± 22.0 h(-1) ) were higher than in subjects who underwent PG (AHIPG 22.0 ± 23.5 h(-1) ) (P < 0.0001). The oxygen desaturation index (ODI) was lower in subjects investigated with PG (ODIPG 18.4 ± 21.7 h(-1) ) compared to subjects investigated with PSG (ODIPSG 23.0 ± 25.3 h(-1) ) but not different when the PSG was indexed by TAT (ODITAT 18.6 ± 21.4 h(-1) , P < 0.65). The proportion of patients with an AHI ≥ 15 was 64% in the subjects who underwent PSG and 47% in the subjects who underwent PG (P < 0.001). Overall, patients investigated using PG are likely to have a 30% lower AHI on average, compared to patients investigated by PSG. This study suggests that PG interpreted using standard guidelines results in underdiagnosis and misclassification of OSA. We advocate the development of PG-specific guidelines for the management of OSA patients., (© 2015 European Sleep Research Society.)

Obstructive sleep apnea is associated with increased motor vehicle accident risk, and improved detection of patients at risk is of importance. The present study addresses potential risk factors in the European Sleep Apnea Database and includes patients with suspected obstructive sleep apnea [n = 8476, age 51.5 (12.5) years, body mass index 31.0 (6.6) kg m(-2) , 82.4% driver's licence holders]. Driving distance (km year(-1) ), driver's licence type, sleep apnea severity, sleepiness and comorbidities were assessed. Previously validated risk factors for accident history: Epworth Sleepiness Scale ≥16; habitual sleep time ≤5 h; use of hypnotics; and driving ≥15 000 km year(-1) were analysed across European regions. At least one risk factor was identified in male and female drivers, 68.75 and 51.3%, respectively. The occurrence of the risk factors was similar across Europe, with only a lower rate in the eastern region (P = 0.001). The mean number of risk factors increased across classes of sleep apnea severity. Frequent driving was prevalent [14.0 (interquartile range 8.0-20.0) × 10(3)  km year(-1) ] and 32.7% of drivers had severe obstructive sleep apnea [apnea-hypopnea index 50.3 (38.8-66.0) n h(-1) ]. Obesity, shorter sleep time and younger age were associated with increased traffic exposure (P ≤ 0.03). In conclusion, the risk factors associated with accident history were common among European patients with suspected obstructive sleep apnea, but varied between geographical regions. There was a weak covariation between occurrence of risk factors and clinically determined apnea severity but frequent driving, a strong risk factor for accidents, was over-represented. Systematic evaluation of accident-related risk factors is important to detect sleep apnea patients at risk for motor vehicle accidents., (© 2014 European Sleep Research Society.)

Hypoxemia is a powerful stimulus of glutamate release in the central nervous system (CNS) and a hallmark phenomenon in sleep disordered breathing (SDB). Glutamate effects that include neuronal damage and apoptosis following hypoxemia and apnea following microinjections in animal models are in part mediated via postjunctional N-methyl-D-aspartate (NMDA) receptors. This was a double blind, randomized, placebo-controlled single dose cross-over study of the NMDA receptor antagonist AR-R15896AR in 15 male patients with moderate to severe SDB. Seven patients received 120 mg and eight patients received 350 mg AR-R15896AR or corresponding placebo (given by 2 h infusion) starting half an hour before estimated sleep onset. AR-R15896AR concentrations were in line with the predicting kinetic model. A standard polysomnographic montage was applied. Repeated plasma samples were obtained in nine patients for analysis of plasma glutamate. Glutamate concentration in plasma did not change overnight and was unrelated to severity of SDB. Overall AHI (apnea-hypopnea index; primary efficacy variable) or investigated oxygen saturation variables were not significantly changed after AR-R15896AR at either dosage level. Side effects were mostly confined to the higher dose level and included vivid dreams, nightmares as well as in two cases mild hallucinations. The previously postulated role of glutamate in SDB could not be confirmed after AR-R15896AR induced NMDA-receptor blockade.

This paper deals with the potential role of two blood pressure regulatory systems in the development of hypertension in obstructive sleep apnoea (OSA). Beside the acute and long-term sympathoexcitation documented in this disease, there seems to be an impaired endothelium-dependent vascular relaxation. In particular, nitric oxide (NO)-mediated vasodilatation was impaired in patients with OSA. Both these changes act to increase blood pressure during physiological conditions. However, they may not be determinants for hypertension development in OSA as no differences between normo- and hypertensive patients with OSA were detected. Nevertheless, an altered balance between the vasoconstrictive influence of the sympathoadrenergic system and the vasodilatory action of NO-dependent vascular relaxation may be of importance in the development of sustained hypertension in OSA.