The relationship between periodic limb movement during sleep and dyslipidaemia in patients with obstructive sleep apnea.

Periodic limb movements during sleep and obstructive sleep apnea are both associated with increased sympathetic tone, and have been proposed as risk factors for heart diseases and, in particular, cardiovascular disease. As sympathetic system activation may lead to dyslipidaemia, periodic limb movements during sleep could be an additional risk factor for cardiovascular disease in patients with obstructive sleep apnea. The aim of the study was to determine whether the presence of periodic limb movements during sleep affects serum lipid levels in obstructive sleep apnea. Total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, non- high-density lipoprotein cholesterol and triglyceride levels were investigated in 4138 patients with obstructive sleep apnea in the European Sleep Apnea Database (ESADA) cohort, divided into those with periodic limb movements during sleep index ≥ 15 per hr (n = 628) and controls (n = 3510). ANCOVA adjusted for age, sex, body mass index, apnea-hypopnea index, alcohol intake, smoking status, diabetes, insomnia and study site was used to assess differences in lipids between periodic limb movements during sleep and controls. Patients with periodic limb movements during sleep (24% female, 54.4 ± 12.1 years, body mass index 31.9 ± 5.8 kg m-2 , apnea-hypopnea index 36.7 ± 25.4 per hr) had higher triglyceride (1.81 ± 1.04 versus 1.69 ± 0.90 mmol L-1 , p = 0.002) and lower high-density lipoprotein cholesterol (1.19 ± 0.34 versus 1.24 ± 0.37 mmol L-1 , p = 0.002) levels, whilst there was no difference in either total cholesterol (4.98 ± 1.10 versus 4.94 ± 1.07 mmol L-1 ), low-density lipoprotein cholesterol (3.04 ± 0.96 versus 2.98 ± 0.98 mmol L-1 ) or non- high-density lipoprotein cholesterol (3.78 ± 1.10 versus 3.70 ± 1.05 mmol L-1 ) concentrations (all p > 0.05). The results remained unchanged after most sensitivity analyses. Patients with obstructive sleep apnea with periodic limb movements during sleep had more prevalent cardiovascular disease (11% versus 6%, p < 0.01). Periodic limb movements during sleep in obstructive sleep apnea is associated with dyslipidaemia independently of important confounders. Our results highlight periodic limb movements during sleep as an additional risk factor for cardiovascular disease in obstructive sleep apnea.

Periodontitis severity in obstructive sleep apnea patients.

OBJECTIVES: This cross-sectional study investigated the stages of periodontitis in obstructive sleep apnea (OSA) patients and risk factors associated with periodontitis severity among them. MATERIALS AND METHODS: A total of 194 patients underwent a polysomnography/polygraphy and were referred to periodontal examination. According to apnea-hypopnea index (AHI), patients were classified as mild OSA (AHI < 15) and moderate to severe OSA (AHI ≥ 15), whereas periodontitis severity was determined by the clinical attachment level (CAL) according to the recent Classification of Periodontal Diseases and Conditions. Patients were grouped into two categories: stages 1 and 2, and stages 3 and 4. RESULTS: Higher AHI values were reported in OSA patients exhibiting periodontitis stages 3 and 4 compared to OSA patients with periodontitis stages 1 and 2 (p = 0.043) and the non-periodontitis group (p = 0.044). A positive correlation was found between AHI and mean CAL (r = 0.215; p = 0.004), and between AHI and plaque scores (r = 0.292; p < 0.001). Following a multivariable regression analysis, AHI was a significant predictor of mean CAL (ß = 0.169; p = 0.031), explaining 16.4% of variability in mean CAL (adjusted R2 = 0.164; p < 0.001). Older patients had higher odds for an increased mean CAL (ß = 0.266; p = 0.001), as well as patients smoking or formerly smoking (ß = 0.305; p < 0.001) whereas visiting a dental medicine doctor once a year or more often was associated with a decreased mean CAL (ß = - 0.182; p = 0.02). CONCLUSIONS: OSA was associated with severe stages of periodontitis along with increased age, smoking, low frequency of dental visits, and poor oral hygiene. CLINICAL RELEVANCE: Screening for periodontitis is recommended for patients with more severe forms of OSA.

The COVID-19 lockdown promotes changes in sleep habits in the Croatian general population.

AIM: To investigate the effects of the coronavirus disease 2019 (COVID-19) lockdown on sleep habits in the Croatian general population. METHODS: In this cross-sectional study, 1173 respondents from the general population (809 women) completed a self-report online questionnaire that gathered demographic data and data on sleep habits and mood changes before and during the COVID-19 lockdown. RESULTS: During the lockdown, bedtime (from 23:11±1:07 to 23:49±1:32 h, P<0.001) and waketime were delayed (from 6:51±1:09 to 7:49±1:40 h, P<0.001). Sleep latency increased from 10 (5-20) to 15 (10-30) minutes (P<0.001). Bedtime and waketime delays were more pronounced in women and respondents younger than 30. Compared with other age groups, respondents younger than 30 more frequently reported insomnia for the first time during the lockdown and had less frequent night-time awakenings (P<0.001), less common problems falling asleep (P<0.001), less frequently felt calm (P<0.001) and rested (P<0.001), but more frequently felt sadness (P<0.001) and fear (P=0.028). CONCLUSION: The effect of the lockdown on sleep needs to be better understood. Sleep hygiene education could serve a first-line lifestyle intervention for people in lockdown experiencing sleep disruption.

The construction of the Split Sleep Questionnaire on sleep habits during the COVID-19 pandemic in the general population.

AIM: To construct a single-format questionnaire on sleep habits and mood before and during the COVID-19 pandemic in the general population. METHODS: We constructed the Split Sleep Questionnaire (SSQ) after a literature search of sleep, mood, and lifestyle questionnaires, and after a group of sleep medicine experts proposed and assessed questionnaire items as relevant/irrelevant. The study was performed during 2021 in 326 respondents distributed equally in all age categories. Respondents filled out the SSQ, the Pittsburgh Sleep Quality Index (PSQI), and State Trait Anxiety Inventory (STAI), and kept a seven-day sleep diary. RESULTS: Cronbach alpha for Sleep Habits section was 0.819, and 0.89 for Mood section. Test-retest reliability ranged from 0.45 (P=0.036) for work-free day bedtime during the pandemic to 0.779 (P<0.001) for sleep latency before the pandemic. Workday and work-free day bedtime during the COVID-19 pandemic assessed with SSQ were comparable to the sleep diary assessment (P=0.632 and P=0.203, respectively), as was the workday waketime (P=0.139). Work-free day waketime was significantly later than assessed in sleep diary (8:19±1:52 vs 7:45±1:20; P<0.001). No difference in sleep latency was found between the SSQ and PSQI (P = 0.066). CONCLUSION: The SSQ provides a valid, reliable, and efficient screening tool for the assessment of sleep habits and associated factors in the general population during the COVID-19 pandemic.

Impact of Sleep Apnea on Cardioembolic Risk in Patients With Atrial Fibrillation: Data From the ESADA Cohort.

BACKGROUND AND PURPOSE: An accurate determination of the cardioembolic risk in patients with atrial fibrillation (AF) is crucial to prevent consequences like stroke. Obstructive sleep apnea (OSA) is a known risk factor for both AF and stroke. We aim to explore a possible association between OSA and an increased cardioembolic risk in patients with AF. METHODS: We assessed data from the ESADA (European Sleep Apnea Database) cohort where patients with known AF and OSA were included. Parameters of OSA severity and related hypoxia like lowest Spo2 and 4% oxygen desaturation index were analyzed. Patients were stratified according to their cardioembolic risk estimated with the CHA2DS2-VASc score. RESULTS: From the initial cohort of 14 646 patients, a final set of 363 patients were included in the analysis. Indices of hypoxia during sleep were associated with increased CHA2DS2-VASc score (4% oxygen desaturation index 17.9 versus 29.6 versus 30.5 events/hour and the lowest Spo2 81.2 versus 77.8 versus 77.5% for low, moderate, and high cardioembolic risk, respectively, P<0.05). CONCLUSIONS: These results support the potential role of OSA-related hypoxia in the risk for cardioembolic complications such as stroke in patients with AF.

Sleep medicine catalogue of knowledge and skills - Revision.

The 'catalogue of knowledge and skills' for sleep medicine presents the blueprint for a curriculum, a textbook, and an examination on sleep medicine. The first catalogue of knowledge and skills was presented by the European Sleep Research Society in 2014. It was developed following a formal Delphi procedure. A revised version was needed in order to incorporate changes that have occurred in the meantime in the International Classification of Sleep Disorders, updates in the manual for scoring sleep and associated events, and, most important, new knowledge in sleep physiology and pathophysiology. In addition, another major change can be observed in sleep medicine: a paradigm shift in sleep medicine has taken place. Sleep medicine is no longer a small interdisciplinary field in medicine. Sleep medicine has increased in terms of recognition and importance in medical care. Consequently, major medical fields (e.g. pneumology, cardiology, neurology, psychiatry, otorhinolaryngology, paediatrics) recognise that sleep disorders become a necessity for education and for diagnostic assessment in their discipline. This paradigm change is considered in the catalogue of knowledge and skills revision by the addition of new chapters.

Clusters of sleep apnoea phenotypes: A large pan-European study from the European Sleep Apnoea Database (ESADA).

BACKGROUND AND OBJECTIVE: To personalize OSA management, several studies have attempted to better capture disease heterogeneity by clustering methods. The aim of this study was to conduct a cluster analysis of 23 000 OSA patients at diagnosis using the multinational ESADA. METHODS: Data from 34 centres contributing to ESADA were used. An LCA was applied to identify OSA phenotypes in this European population representing broad geographical variations. Many variables, including symptoms, comorbidities and polysomnographic data, were included. Prescribed medications were classified according to the ATC classification and this information was used for comorbidity confirmation. RESULTS: Eight clusters were identified. Four clusters were gender-based corresponding to 54% of patients, with two clusters consisting only of men and two clusters only of women. The remaining four clusters were mainly men with various combinations of age range, BMI, AHI and comorbidities. The preferred type of OSA treatment (PAP or mandibular advancement) varied between clusters. CONCLUSION: Eight distinct clinical OSA phenotypes were identified in a large pan-European database highlighting the importance of gender-based phenotypes and the impact of these subtypes on treatment prescription. The impact of cluster on long-term treatment adherence and prognosis remains to be studied using the ESADA follow-up data set.

Using Cutaneous Receptor Vibration to Uncover the Effect of Transcranial Magnetic Stimulation (TMS) on Motor Cortical Excitability.

BACKGROUND Little is known about how vibrational stimuli applied to hand digits affect motor cortical excitability. The present transcranial magnetic stimulation (TMS) study investigated motor evoked potentials (MEPs) in the upper extremity muscle following high-frequency vibratory digit stimulation. MATERIAL AND METHODS High-frequency vibration was applied to the upper extremity digit II utilizing a miniature electromagnetic solenoid-type stimulator-tactor in 11 healthy study participants. The conditioning stimulation (C) preceded the test magnetic stimulation (T) by inter-stimulus intervals (ISIs) of 5-500 ms in 2 experimental sessions. The TMS was applied over the primary motor cortex for the hand abductor pollicis-brevis (APB) muscle. RESULTS Dunnett's multiple comparisons test indicated significant suppression of MEP amplitudes at ISIs of 200 ms (P=0.001), 300 ms (P=0.023), and 400 ms (P=0.029) compared to control. CONCLUSIONS MEP amplitude suppression was observed in the APB muscle at ISIs of 200-400 ms, applying afferent signaling that originates in skin receptors following the vibratory stimuli. The study provides novel insight on the time course and MEP modulation following cutaneous receptor vibration of the hand digit. The results of the study may have implications in neurology in the neurorehabilitation of patients with increased amplitude of MEPs.

The effect of COVID-19 lockdown on lifestyle and mood in Croatian general population: a cross-sectional study.

AIM: To investigate the effect of the coronavirus 2019 (COVID-19) lockdown on lifestyle behaviors and mood changes in the Croatian general population. METHODS: During ten days of the COVID-19 lockdown in Croatia, 3027 respondents (70.3% female) from the general population completed an online, self-report questionnaire. Demographic data and data on lifestyle habits and mood changes before and during the COVID-19 lockdown were collected. RESULTS: A total of 95.64% of respondents reported to follow most or all restrictions, with female sex (P<0.001) and higher education level (P<0.001) being associated with higher restriction compliance. Women smoked an increased number of cigarettes (P<0.001). The proportion of respondents of both sexes who did not drink or drank 7 drinks per week or more increased (P<0.001). Women also reported lower frequency (P=0.001) and duration of physical exercise (P<0.001). In total, 30.7% of respondents gained weight, with female sex (OR, 2.726) and higher BMI (OR, 1.116; both P<0.001) being associated with an increased likelihood of gaining weight. Both men and women felt more frequently afraid (P<0.001), discouraged (P<0.001), and sad (P<0.001). CONCLUSION: Public health authorities should promote the adoption of healthy lifestyles in order to reduce long-term negative effects of the lockdown.

The effect of age and gender on cognitive and psychomotor abilities measured by computerized series tests: a cross-sectional study.

AIM: To assess age- and gender-associated differences in cognitive and psychomotor abilities measured by the Complex Reactionmeter Drenovac (CRD-series) tests. METHODS: This cross-sectional study, conducted between 2009 and 2019, enrolled 3420 participants (2012 women) in the age ranging from 18 to 88 years. The participants solved three CRD-series chronometric tests: discrimination of the light signal position (CRD311), complex psychomotor coordination (CRD411), and simple arithmetic operations (CRD11). We analyzed total test solving time (TTST), minimum single task solving time (MinT), number of errors, initial dissociation, and start, end, and total ballasts as measures of wasted time in the first half of the test, second half of the test, and total test time, respectively. RESULTS: Age was positively associated with MinT and TTST in all used tests (P<0.001), while initial dissociation, start ballast, and end ballast significantly increased with age (P<0.001). On the CRD11 test, men had shorter TTST than women (P=0.012), shorter start, end, and total ballasts (P<0.001), and made fewer errors than women (P<0.001). On the CRD311 test, women had shorter start (P=0.002), end, and total ballast (P<0.001) than men. On the CRD411 test, men performed better than women on all variables (P<0.001). CONCLUSION: Decreased cognitive and psychomotor abilities measured by the CRD-series tests were associated with advanced age. Men performed better than women on simple arithmetic and complex psychomotor coordination tests, whereas women lost less time on the test of light signal position discrimination.

Catestatin serum levels are increased in male patients with obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is a complex sleep disorder associated with autonomic and sympathetic dysregulation. To the contrary, catestatin, an endogenous pleiotropic peptide cleaved from chromogranin A, is known for its inhibitory effects on catecholamine release and sympathetic activity. The aims of the study were to determine catestatin serum levels among male OSA patients compared to healthy control subjects and to explore associations of catestatin with anthropometric, polysomnographic, and lipid profile parameters. METHODS: Seventy-eight male OSA patients aged 50.3 ± 8.8 years and 51 age/sex/BMI-matched control subjects aged 50.4 ± 7.8 years were enrolled in the study. Catestatin serum levels were determined by an enzyme-linked immunosorbent assay (ELISA). RESULTS: Catestatin serum levels were significantly higher among OSA patients compared to control subjects (2.9 ± 1.2 vs. 1.5 ± 1.1 ng/mL, p < 0.001). Serum catestatin levels significantly correlated with apnea-hypopnea index (AHI) among non-obese OSA subjects (r = 0.466, p = 0.016; ß = 0.448, p = 0.026), while in whole OSA population, catestatin levels significantly correlated with neck circumference (r = 0.318, p < 0.001; ß = 0.384, p < 0.001) and high-density lipoprotein (HDL) cholesterol (r = - 0.320, p < 0.001; ß = - 0.344, p < 0.001). In multivariate-adjusted regression model, serum catestatin was significant and independent predictor of OSA status (OR 4.98, 95% CI 2.17-11.47, p < 0.001). CONCLUSIONS: Catestatin serum levels are significantly increased in male OSA population and positively correlate with disease severity in non-obese patients. OSA status is independently predicted by catestatin levels; however, this finding is restricted to patients with moderate-to-severe disease. Further studies are necessary to elucidate the mechanistic role of catestatin in the complex pathophysiology of OSA.

Effects of CPAP therapy on cognitive and psychomotor performances in patients with severe obstructive sleep apnea: a prospective 1-year study.

STUDY OBJECTIVES: We prospectively investigated the effects of continuous positive airway pressure (CPAP) on long-term cognitive and psychomotor performances, and excessive daytime sleepiness in severe obstructive sleep apnea (OSA) patients. METHODS: A total of 40 patients were recruited and 23 patients with severe OSA fully completed the study protocol to investigate the effects of CPAP therapy on psychomotor performance at 1, 3, and 6 months and 1 year following initiation of the therapy. Psychomotor CRD-series tests measuring reaction times of light stimulus perception, solving simple arithmetic operations, and complex psychomotor limb coordination, were used in this study. The data collected following CPAP therapy were compared to baseline values prior to the CPAP treatment for each patient. RESULTS: All of the measured variables improved following CPAP treatment. However, the most pronounced effect was observed in improvement of reaction times to complex psychomotor limb coordination test (p < 0.05). Self-reported evaluation of excessive daytime sleepiness measured by Epworth Sleepiness Scale (ESS) showed significant decrease from 10.0 ± 1.1 before to 3.5 ± 0.5 (p < 0.001), after 1 year on CPAP therapy. CONCLUSIONS: The CPAP therapy improved cognitive and psychomotor performance on CRD-series tests with the most significant improvement observed in complex psychomotor limb coordination of severe OSA patients.

Prevalence of obstructive sleep apnea in male patients with surgically treated maxillary and zygomatic fractures

Background: Midface fractures can cause airway obstruction and breathing disturbances. The purpose of the present study was to determine the prevalence of undiagnosed obstructive sleep apnea (OSA) among patients with surgically treated maxillary and zygomatic fractures. Methods: We retrospectively analyzed the medical records of 44 patients who had undergone surgical treatment of maxillary or zygomatic fractures between Jan. 1, 2003, and Dec. 31, 2013 at a single centre. All participants underwent polygraphy testing and were asked to complete the STOP (snoring, tiredness, observed apnea and high blood pressure) questionnaire, Nasal Obstruction Symptom Evaluation (NOSE) scale and Epworth Sleepiness Scale. Results: There were 27 participants (61%) with maxillary fracture and 17 (39%) with zygomatic fracture. Obstructive sleep apnea was diagnosed in 24 (54%) of the 44 participants, of whom 15 (62%) had maxillary fractures and 9 (38%) had zygomatic fractures. Participants with OSA had a mean Apnea­Hypopnea Index (AHI) of 15.5 (standard deviation [SD] 9.7) events/h, compared to 2.4 (SD 1.5) events/h for those without OSA (p < 0.001). Of the 30 participants with nose obstruction, 18 (60%) had an AHI of 5 or greater. Conclusion: The results suggest that the prevalence of OSA was higher in surgical patients with midface fractures, independent of the type of fracture, than in the general population. The NOSE scale results showed significant correlation with the presence of OSA.

Contexte: Les fractures affectant la portion médiane du visage peuvent provoquer une obstruction des voies respiratoires et gêner la respiration. La présente étude avait pour but de déterminer la prévalence de l'apnée obstructive du sommeil (AOS) non diagnostiquée chez des patients ayant été traités chirurgicalement pour des fractures du maxillaire et de l'os zygomatique. Méthodes: Nous avons analysé rétrospectivement les dossiers médicaux de 44 patients ayant subi un traitement chirurgical pour une fracture du maxillaire ou de l'os zygomatique entre le 1er janvier 2003 et le 31 décembre 2013 dans un seul établissement. Tous les participants ont subi un test polygraphique et ont été invités à répondre aux questionnaires STOP (snoring, tiredness, observed apnea et high blood pressure), NOSE (Nasal Obstruction Symptom Evaluation), de même qu'à l'échelle de somnolence d'Epworth. Résultats: Vingt-sept participants (61 %) avaient subi une fracture du maxillaire et 17 (39 %) de l'os zygomatique. L'AOS a été diagnostiquée chez 24 participants sur 44 (54 %), dont 15 (62 %) avaient subi une fracture du maxillaire et 9 (38 %) une fracture de l'os zygomatique. Les participants qui présentaient une AOS avaient un indice d'apnée-hypopnée (IAH) moyen de 15,5 (écart-type [É.-T.] 9,7) événements/h, contre 2,4 (É.-T. 1,5) événement/h pour les participants indemnes d'ASO (p < 0,001). Parmi les 30 participants qui avaient une obstruction nasale, 18 (60 %) avaient un IAH de 5 ou plus. Conclusion: Ces résultats donnent à penser que la prévalence de l'AOS était plus élevée chez les patients opérés pour une fracture affectant la portion médiane du visage (indépendamment du type de fracture) que dans la population générale. Les résultats au questionnaire NOSE ont montré une corrélation significative avec la présence d'AOS.

Phrenic long-term depression evoked by intermittent hypercapnia is modulated by serotonergic and adrenergic receptors in raphe nuclei.

Intermittent hypercapnia evokes prolonged depression of phrenic nerve activity (phrenic long-term depression, pLTD). This study was undertaken to investigate the role of 5-HT and α2-adrenergic receptors in the initiation of pLTD. Adult male urethane-anesthetized, vagotomized, paralyzed, and mechanically ventilated Sprague-Dawley rats were exposed to a protocol of acute intermittent hypercapnia (AIHc; 5 episodes of 15% CO2 in air, each episode lasting 3 min). The experimental group received microinjection of the selective 5-HT1A receptor agonist 8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT), the broad-spectrum 5-HT antagonist methysergide, or the α2-adrenergic antagonist yohimbine, whereas the control group received microinjection of 0.9% saline into the caudal raphe region. Peak phrenic nerve activity (pPNA) and burst frequency ( f) were analyzed during baseline (T0), during 5 hypercapnic episodes (THc1-THc5), and at 15, 30, and 60 min after the end of the last hypercapnic episode. In the control group, pPNA decreased 60 min after the end of the last hypercapnic episode compared with baseline values, i.e., pLTD developed ( P = 0.023). In the 8-OH-DPAT group, pPNA significantly decreased at T15, T30, and T60 compared with baseline values, i.e., pLTD developed ( P = 0.01). In the methysergide and yohimbine groups, AIHc did not evoke significant changes of the pPNA at T15, T30, and T60 compared with baseline values. In conclusion, activation of 5-HT1A receptors accentuated induction of pLTD, whereas blockade of α2-adrenergic receptors prevented development of pLTD following AIHc in anesthetized rats. These results suggest that chemical modulation of 5-HT and α2-adrenergic receptors in raphe nuclei affects hypercapnia-induced pLTD, offering important insights in understanding the mechanisms involved in development of respiratory plasticity. NEW & NOTEWORTHY Hypercapnia is a concomitant feature of many breathing disorders, including obstructive sleep apnea. In this study, acute intermittent hypercapnia evoked development of phrenic long-term depression (pLTD) 60 min after the last hypercapnic episode that was preserved if the selective 5-HT1A receptor agonist 8-hydroxy-2-(dipropylamino)tetralin hydrobromide was microinjected in the caudal raphe region before the hypercapnic stimulus. This study highlights that both 5-HT and adrenergic receptor activation is needed for induction of pLTD in urethane-anesthetized rats following intermittent hypercapnia exposure.

Clinical presentation of patients with suspected obstructive sleep apnea and self-reported physician-diagnosed asthma in the ESADA cohort.

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.

Good and poor sleepers among OSA patients: sleep quality and overnight polysomnography findings.

Previous studies aimed to determine if Pittsburgh sleep quality index (PSQI) is a valid screening instrument for obstructive sleep apnea, indicating its disadvantages. However, the rationale of PSQI use in sleep clinics is not the screening, but the assessment of sleep quality itself. Therefore, the aims of this study were to investigate the sleep quality in obstructive sleep apnea patients and to identify the cutoff point for differentiation of "good" and "poor" sleepers among them. We constructed the Croatian version of PSQI and assessed its psychometric properties. The protocol of the study included the assessment of sleep quality in 130 obstructive sleep apnea patients and 75 healthy control subjects. All subjects completed the Croatian version of the PSQI, and the patients underwent overnight polysomnography screening. Obstructive sleep apnea patients had higher values of the global PSQI component score, indicating lower sleep quality, compared to a healthy control group (p < 0.001). The psychometric properties of PSQI scores in the prediction of normal sleep efficiency indicate that the cutoff score of 9.5 differentiates patients in total sleep time (p <  0.001), REM duration (p = 0.014), sleep efficiency (p = 0.001), time spent awake during sleep (p = 0.006), after sleep (p = 0.024), and after sleep onset (p = 0.001). In OSA patients, a PSQI cutoff score of 9.5 differentiated good and poor sleepers significantly in total sleep time, REM duration, time spent awake during sleep, and WASO time. Current findings enhance the interpretability of PSQI results in a population of OSA patients.

Intermittent hypercapnia-induced phrenic long-term depression is revealed after serotonin receptor blockade with methysergide in anaesthetized rats.

NEW FINDINGS: What is the central question of this study? Intermittent hypercapnia is a concomitant feature of breathing disorders. Hypercapnic stimuli evoke a form of respiratory plasticity known as phrenic long-term depression in experimental animals. This study was performed to investigate the putative role of serotonin receptors in the initiation of phrenic long-term depression in anaesthetized rats. What is the main finding and its importance? Phrenic nerve long-term depression was revealed in animals pretreated with the serotonin broad-spectrum antagonist, methysergide. This study highlights that serotonin receptors modulate respiratory plasticity evoked by acute intermittent hypercapnia in anaesthetized rats. This study was performed to test the hypothesis that intermittent hypercapnia can evoke a form of respiratory plasticity known as long-term depression of the phrenic nerve (pLTD) and that 5-HT receptors play a role in the initiation of pLTD. Adult male urethane-anaesthetized, vagotomized, paralysed, mechanically ventilated Sprague-Dawley rats were exposed to an acute intermittent hypercapnia protocol. One group received i.v. injection of the non-selective 5-HT receptor antagonist methysergide and another group received i.v. injection of the selective 5-HT1A receptor antagonist WAY-100635 20 min before exposure to intermittent hypercapnia. A control group received i.v. injection of saline. Peak phrenic nerve activity and respiratory rhythm parameters were analysed at baseline (T0), during each of five hypercapnic episodes, and 15, 30 and 60 min (T60) after the last hypercapnia. Intravenous injection of methysergide before exposure to acute intermittent hypercapnia induced development of amplitude pLTD at T60 (decreased by 46.1 ± 6.9%, P = 0.003). Conversely, in control and WAY-100635-pretreated animals, exposure to acute intermittent hypercapnia did not evoke amplitude pLTD. However, a long-term decrease in phrenic nerve frequency was evoked both in control (42 ± 4 breaths min(-1) at T0 versus 32 ± 5 breaths min(-1) at T60; P = 0.036) and in methysergide-pretreated animals (42 ± 2 breaths min(-1) at T0 versus 32 ± 3 breaths min(-1) at T60; P = 0.028). In WAY-100635 pretreated animals, frequency pLTD was prevented. These results suggest that 5-HT receptors modulate respiratory plasticity induced by acute intermittent hypercapnia in anaesthetized rats.

Reduced evoked motor and sensory potential amplitudes in obstructive sleep apnea patients.

It is unknown to what extent chronic intermittent hypoxaemia in obstructive sleep apnea causes damage to the motor and sensory peripheral nerves. It was hypothesized that patients with obstructive sleep apnea would have bilaterally significantly impaired amplitudes of both motor and sensory peripheral nerve-evoked potentials of both lower and upper limbs. An observational study was conducted on 43 patients with obstructive sleep apnea confirmed by the whole-night polysomnography, and 40 controls to assess the relationship between obstructive sleep apnea and peripheral neuropathy. All obstructive sleep apnea subjects underwent standardized electroneurographic testing, with full assessment of amplitudes of evoked compound muscle action potentials, sensory neural action potentials, motor and sensory nerve conduction velocities, and distal motor and sensory latencies of the median, ulnar, peroneal and sural nerves, bilaterally. All nerve measurements were compared with reference values, as well as between the untreated patients with obstructive sleep apnea and control subjects. Averaged compound muscle action potential and sensory nerve action potential amplitudes were significantly reduced in the nerves of both upper and lower limbs in patients with obstructive sleep apnea compared with controls (P < 0.001). These results confirmed that patients with obstructive sleep apnea had significantly lower amplitudes of evoked action potentials of both motor and sensory peripheral nerves. Clinical/subclinical axonal damage exists in patients with obstructive sleep apnea to a greater extent than previously thought.

Effects of mandibular advancement device treatment on arterial stiffness and glucose metabolism in patients with mild to moderate obstructive sleep apnea: a prospective 1 year study.

STUDY OBJECTIVES: An independent association between obstructive sleep apnea (OSA) and cardiovascular events has been reported, suggesting that OSA may lead to cardiometabolic dysregulation. We prospectively investigated the effect of mandibular advancement device (MAD) treatment on arterial stiffness, glucose metabolism, and certain inflammatory markers as predictors of cardiometabolic risk in mild to moderate OSA patients. METHODS: A total of 18 patients with mild to moderate OSA were prospectively enrolled in the study to determine the effects of MAD treatment at 3 months and 1 year following initiation of the treatment. Sleep studies, arterial stiffness assessment, and laboratory analyses were obtained at the baseline and at the time of follow-up. The data collected at 1 year were compared to baseline values. RESULTS: There was a significant decrease in apnea-hypopnea index (AHI) after 1 year of treatment when compared to baseline (22.9 ± 5.9 to 9.7 ± 4.5, P < 0.001). Furthermore, MAD treatment was associated with reduced levels of fasting plasma glucose values after 1 year of treatment (5.3 ± 0.5 to 4.9 ± 0.5 mmol/L, P < 0.001), as well as fasting plasma insulin values (14.1 ± 7.8 to 10.9 ± 6.4 µU/mL, P < 0.05) and HOMA-IR (3.3 ± 1.8 to 2.4 ± 1.4, P < 0.001). There was significant improvement in pulse wave velocity (9.3 ± 1.9 m/s at baseline to 8.1 ± 1.7 m/s, P < 0.05) after 1 year of treatment. Plasma level of an inflammatory marker fibrinogen decreased significantly from 3.4 ± 0.7 at baseline to 3.0 ± 0.9, (P < 0.05) at 1-year follow-up. CONCLUSIONS: The MAD treatment improved arterial stiffness, glucose metabolism, and insulin resistance in mild to moderate OSA patients after 1 year of treatment.

No difference in the intention to engage others in academic transgression among medical students from neighboring countries: a cross-national study on medical students from Bosnia and Herzegovina, Croatia, and Macedonia.

AIM: To asses if the level of intention to engage others in academic transgressions was comparable among medical students from five schools from neighboring Southern-European countries: Croatia, Bosnia and Herzegovina, and Macedonia; and medical students from western EU studying at Split, Croatia. METHODS: Five medical schools were surveyed in 2011, with ≥87% of the targeted population sampled and a response rate of ≥76%. Students' intention to engage a family member, friend, colleague, or a stranger in academic transgression was measured using a previously validated the Intention to Engage Others in Academic Transgression (IEOAT) questionnaire and compared with their intention to ask others for a non-academic, material favor. Data on students' motivation measured by Work Preference Inventory scale, and general data were also collected. Multiple linear regression models of the intention to engage others in a particular behavior were developed. RESULTS: The most important determinants of the intention to engage others in academic transgression were psychological factors, such as intention to ask others for a material favor, or students' motivation (median determinant's ß of 0.18, P≤0.045 for all), whereas social and cultural factors associated with the country of origin were either weak (median ß of 0.07, P≤0.031) or not relevant. A significant proportion of students were aware of the ethical violations in academic transgressions (P≤0.004 for all transgressions), but a large proportion of students also perceived academic cheating as a collective effort and were likely to engage people randomly (P≤0.001 for all, but the most severe transgression). This collective effort was more pronounced for academic than non-academic behavior. CONCLUSION: Culture differences among neighboring Southern-European countries were not an important determinant of the intention to engage others in academic cheating.