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The understanding of narcolepsy has been enhanced by neurophysiologic investigations in humans and by pharmacologic and biochemical studies using the canine model of narcolepsy. Repetitive microsleeps have a more deleterious effect on performance than several short complete naps during the day. Under normal living conditions, the nocturnal sleep of narcoleptic patients is disrupted, and the spectral analysis of central EEG leads shows less delta power density per epoch than it does in age-matched controls, who have an absence or decrease of the usual decay in delta power across the night. Cataplexy is associated with a drop in H-reflex, even during partial cataplectic attacks. Monitoring of heart rate and intra-arterial blood pressure during cataplexy in humans shows a decrease in heart rate and an increase in blood pressure with onset of cataplexy, but the change in heart rate is secondary to the change in blood pressure. Investigations of narcoleptic Doberman pinschers have implicated several neurotransmitters in the brainstem and amygdala. In vivo dialysis and in situ injections of carbachol indicate that the pontine reticular formation is not the only muscarinic cholinergic region involved, but data support the existence of a multisynaptic descending pathway involved in the muscle atonia of cataplexy. Carbachol injections into the basal forebrain induce status cataplecticus. Experimental findings suggest a hypersensitivity of the overall muscarinic cholinergic system and that this hypersensitive cholinergic system is linked to the limbic system. An increase in the postsynaptic D2 dopaminergic receptor is observed in the amygdala of narcoleptic dogs compared with controls, with impairment of dopamine release. The associated findings suggest that an abnormal cholinergic-dopaminergic interaction could underlie the pathophysiology of narcolepsy.

Introduction Background: Several questionnaires have been used to screen for sleep-disordered breathing (SDB). Most of them have been validated in selected clinical populations, and little is known about their predictive performance in the general population. Objectives To investigate the accuracy of four questionnaires used for SDB screening in the general population: the Berlin Questionnaire (BQ), the Epworth Sleepiness Scale (ESS), the STOP-Bang (SB) and the adjusted-neck circumference (neck+). Materials and methods 2115 subjects (50.4% women, 58.4 ± 11.0 years old, BMI 26.2 ± 4.4 kg/m2) participating in an ongoing population-based sleep cohort study (HypnoLaus, Lausanne, Switzerland) underwent complete polysomnographic recordings at home. Respiratory events were scored according to the AASM 2013 criteria. Prevalence of SDB was determined for apnea–hypopnea index (AHI) thresholds of ⩾15 and ⩾30. Interviewers administered the BQ and the ESS and calculated SB and neck+. SB includes the following items: snoring, daytime Tiredness, Observed apnea, high blood Pressure, Body-mass index ⩾35 kg/m2, Age ⩾ 50 yr, Neck girth ⩾ 40 cm, and male Gender. Neck + is obtained by measuring the neck girth in cm and adding 3 cm for the presence of snoring, 3 cm for observed apnea and 4 cm for high blood pressure. Subjects were considered at increased risk for SDB if BQ is positive in ⩾2 categories, ESS score ⩾11, SB score ⩾3 and neck+ ⩾43 cm. Assessment of questionnaire included their sensitivity, specificity, positive-predicted value (PPV) and negative-predicted value (NPV). Results Prevalence of SDB with AHI thresholds of ⩾15 and ⩾30 were respectively 36.4% and 15.0%. Percentages of positive BQ was 25.3%, ESS:13.4%, SB: 41.3% and neck+:29.0%. For an AHI ⩾ 15, sensitivity, specificity, PPV and NPV were respectively: BQ (39.4%, 82.7%, 56.6% and 70.5%), ESS (13.5%, 86.7%, 35.8% and 64.5%), SB (67.3%, 72.8%, 57.3% and 80.4%) and neck+ (52.3%, 83.8%, 64.0% and 76.1%). For an AHI ⩾ 30, sensitivity, specificity, PPV and NPV were respectively: BQ (48.7%, 78.8%, 28.8% and 89.7%), ESS (13.1, 86.6%, 14.2% and 85.4%), SB (81.7%, 65.6%, 28.7% and 95.5%) and neck+ (69.8%, 77.9%, 34.6% and 93.9%). Conclusion Our population-based study suggests that questionnaires such as BQ, ESS, SB and neck+ could be used to rule out severe SDB considering their strong NPV. However they do not seem suitable to screen for moderate to severe SDB in the general population. Acknowledgements Funding : Ligue pulmonaire vaudoise, Fondation Leenaards, Fond national Suisse and GSK.

Introduction Restless Legs Syndrome (RLS) and periodic leg movements during sleep (PLMS) can occur as a primary disorder or as a secondary condition. The claim that antidepressant use induces RLS or PLMS is controversial and has significant implications considering the widespread use of these medications. The aim of this study was to explore the association between antidepressant drugs intake and the frequency of both RLS and PLMS in a large unselected middle-aged general population sample. Materials and methods Data from 5064 subjects (2542 women, mean age 56.7 ± 10.1) participating in an ongoing population-based cohort study (HypnoLaus, Lausanne, Switzerland) was collected. All them completed a series of sleep related questionnaires and 2019 underwent polysomnographic recordings at home. RLS was ascertained by the presence of the 4 basic diagnostic criteria of the International Restless Legs Syndrome Study Group. PLMS index (PLMSI) was determined according to AASM 2007 criteria. A PLMSI > 15/h was considered to be abnormal. Results Among the 5064 participants, 457 (9%) were taking antidepressive drugs: 291 (5.7%) took SSRIs, 44 (0.8%) tricyclics and 122 (2.4%) other antidepressive drugs (a heterogeneous group including Trazodone, Mirtazapine, Mianserine, Venlafaxine, Bupropion, Duloxetine). Overall, the prevalence of RLS in subjects taking antidepressive drugs was 21% vs 12.1% in the other subjects (p 0.001). Analyses of individual antidepressants class revealed an association between RLS and SSRIs (RR = 1.78, CI = 1.32–2.42) and for the group “other antidepressive drugs” (RR = 1.8, CI = 1.14–2.84) but no association was found for tricyclic antidepresants, after adjusting for age, gender, diabetes (yes/no), neuroleptic use (yes/no) and glomerular filtration rate. Among the 2019 participants that underwent PSG, 131 (6.5%) took SSRIs, 18 (0.9%) took tricyclics and 48 (2.4%) took other antidepressive drugs. The prevalence of PLMSI > 15/h in subjects taking antidepressive drugs was 34.4% (vs. 26.1%, p = 0.039). A significant association was found between PLMSI > 15/h and SSRIs (RR = 1.84, CI = 1.23–2.76) and tricyclics (RR = 3.84, CI = 1.44–10.2), but no for the group other antidepressants, after adjusting for confounding factors. Conclusion RLS and PLMS in the general population are associated with antidepressant use. SSRIs are associated with RLS and PLMS whereas tricyclic are associated only with PLMS. Acknowledgements Funding: Fondation Leenaards, FNS, GSK, Ligue Pulmonnaire Vaudoise and CIRS.

Introduction "Real altitude" (e.g. hypobaric hypoxia) has been reported to impair sleep and induce sleep disordered breathing (SDB). It is however not clear whether for the same ambient Oxygen pressure (PO2) "simulated altitude" in a hypoxic chamber (e.g. normobaric hypoxia;) generates similar sleep alterations. Materials and methods Full polysomnography was performed on 13 healthy volunteers (33.9±9.1y.o, BMI: 23.5±2.2kg/m 2 ) under three conditions: Hypobaric hypoxia (HH, Junfraujoch Switzerland, 3454m), normobaric hypoxia (NH, Sion, Switzerland, 500m, FiO 2 =0.138 ) and Normobaric normoxia (NN, control night, Sion). NN and NH recordings were performed in a hypoxic chamber (randomized order, double blind). Polysomnography recordings were performed and scored according to the AASM recommendations. Results For SDB, compared to NN condition, apnea hypopnea index (AHI) increased significantly in both hypoxic conditions (ANOVA): NN 7.1±1.2/h, NH 35.9±11.2/h ( p =0.04), HH 38.0±9.7/h (p=0.02). The same was found for hypopnea: NN 6.7±1.2, NH 18.3±4.4 ( p =0.04), HH 25.3±5.2 ( p =0.004), oxygen desaturation index (ODI3%): NN 3.8±0.5/h, NH 43.9±10.9/h ( p =0.008), HH 53.3±9.9/h ( p =0.0009) and mean oxygen saturation (SaO 2 ): NN 96.5±0.2%, NH 83.6±05% ( p p 2 : −2.4% ( p =0.04), and an increase in hypopnea index: +7/h ( p =0.04) but no difference in AHI or central sleep apnea. Regarding sleep, compared to NN, there was in NH and HH a significant decrease in total sleep time: NN 388±13min, NH 317±18min ( p =0.01), HH 351±17min ( p =0.05), a significant increase in microarousal index: NN 17.3±1.8/h, NH 26.2±3.9/h ( p =0.03), HH 24.6±3.8 ( p =0.05) and a decrease in sleep efficiency between NN and HH: 8.4% ( p =0.027). We also observed a significant increase in heart rate in hypoxic condition: NN 48.1±1.5, NH 54.7±1.6 ( p =0.001), HH 61.2±2.7 ( p =0.002). HR in HH was significantly higher (+6.5bpm, p =0.018) than in NH. Conclusion Compared to NN, both HH and NH conditions increased AHI, hypopnea index, ODI 3%, heart rate and decreased total sleep time and mean SaO2. There was a further decrease in mean SpO 2 and increase in HR and hypopnea in HH compared to NH, suggesting that HH and NH may have different physiological effect despite the same PO2. Acknowledgement Swiss national science foundation.

Introduction Recent research has identified relationships between sleep duration and quality and increased risk of cardiometabolic disorders. Most previous studies used self-reported sleep duration or quality, but little is known about the objective sleep parameters underlying these associations. The aim of this study was to explore the association between sleep structure measured by polysomnography (PSG) and cardiometabolic disorders in a large unselected middle-aged general population sample. Materials and methods 2019 subjects (49.9% males, 57.6 ± 11.1 years old, BMI 25.4 ± 4.4 kg/m2) participating in an ongoing population- based sleep cohort (HypnoLaus, Lausanne, Switzerland) underwent full PSG recordings at home. All subjects had an extensive clinical workup including medical history, fasting glucose, morning systolic (SBP) and diastolic (DBP) blood pressure measurements. PSG were scored according to AASM 2007 scoring criteria. Results For the whole group there was, after adjustment for age, statistically significant correlations between cardiometabolic disorders and sleep parameters. The highest correlation coefficient values were obtained for % of slow wave sleep (SWS) and SBP (r2 = −0.18, p 0.001), DBP (r2 = −0.13, p 0.01), glycemia (r2 = −0.18, p 0.001) and BMI (r2 = −0.17, p 0.001); and for total arousal index (AI) and SBP (r2 = 0.16, p 0.001), DBP (r2 = 0.13, p 0.01), glycemia (r2 = 0.19, p 0.001) and BMI (r2 = 0.19, p 0.001). After excluding subjects with sleep disordered breathing and periodic limb movements (those with an apnea/hypopnea index -AHI- > 15/h and a periodic leg movement index -PLMSI- > 15/h) significant correlations remained between: SWS and SBP (r2 = −0.17, p 0.05), glycemia (r2 = −0.22, p 0.01) and BMI (r2 = −0.25, p 0.01). Significant associations (age-adjusted) were found between: SWS and BMI categories (p 0.001), diabetes (p = 0.01), hypertension (p = 0.004) and metabolic syndrome (MetSynd,p = 0.002); and between AI and BMI categories (p 0.001), diabetes (p 0.001), hypertension (p 0.001) and MetSynd (p 0.001). After excluding subjects with abnormal AHI/PLMI significant associations remained between: SWS and BMI categories (p 0.001) and hypertension (p = 0.01); and between AI and BMI categories (p = 0.003), diabetes (p 0.001) and MetSynd (p = 0.02). Conclusion Objectively measured sleep fragmentation and reduced SWS are associated with cardiometabolic disturbances in the general population. Acknowledgements Funding: Fondation Leenaards, FNS, GSK, Ligue Pulmonnaire Vaudoise and CIRS.

Corrigendum: Genome-wide association study identifies new HLA class II haplotypes strongly protective against narcolepsy

Guidelines recommend cognitive behavioural therapy for insomnia (CBT-I) as first-line treatment for chronic insomnia, but it is not clear how many primary care physicians (PCPs) in Switzerland prescribe this treatment. We created a survey that asked PCPs how they would treat chronic insomnia and how much they knew about CBT-I. The survey included two case vignettes that described patients with chronic insomnia, one with and one without comorbid depression. PCPs also answered general questions about treating chronic insomnia and about CBT-I and CBT-I providers. Of the 820 Swiss PCPs we invited, 395 (48%) completed the survey (mean age 54 years; 70% male); 87% of PCPs prescribed sleep hygiene and 65% phytopharmaceuticals for the patient who had only chronic insomnia; 95% prescribed antidepressants for the patient who had comorbid depression. In each case, 20% of PCPs prescribed benzodiazepines or benzodiazepine receptor agonists, 8% prescribed CBT-I, 68% said they knew little about CBT-I, and 78% did not know a CBT-I provider. In the clinical case vignettes, most PCPs treated chronic insomnia with phytopharmaceuticals and sleep hygiene despite their lack of efficacy, but PCPs rarely prescribed CBT-I, felt they knew little about it, and usually knew no CBT-I providers. PCPs need more information about the benefits of CBT-I and local CBT-I providers and dedicated initiatives to implement CBT-I in order to reduce the number of patients who are prescribed ineffective or potentially harmful medications.

Medical use of chronic opioids has recently increased in Switzerland. Even though their effect on daytime vigilance tends to disappear after some time, 70% of chronic opioid users will suffer from sleep disordered breathing. Most of them will show an ataxic breathing during sleep with mostly central apnea alternating with short breathing periods, but long hypopnea may also occur. Treatment with continuous positive airway pressure (CPAP) is usually ineffective. More sophisticated ventilatory modes such as bilevel ventilation with backup respiratory rate or adaptive servoventilation are often required. Older patients with concomitant COPD or obstructive sleep apnea are at higher risk of developing nocturnal breathing disorders.

There are many case reports of serious complications and death among obstructive sleep apnea patients (OSA) during general anesthesia or postoperative analgesia. Sedatives and anesthetic agents, pharyngeal anatomy of these patients, opiates given for analgesia, and post operative REM sleep rebound represent potential hazards for general anesthesia in OSA patients. Ideally these patients should be treated with continuous positive airway pressure (CPAP) during premedication, directly after extubation and during postoperative analgesia. Unfortunately, only about 20% of these patients are diagnosed before surgery. A special attention should be given to the symptoms and signs suggestive of OSA during preoperative visits. Screening tests should be performed in patients with suspected OSA and, if positive, a treatment should be initiated.

The automatic detection of sleep apnea episodes, without the need of polysomnography and outside a clinical facility, could help facilitate the diagnosis of this disorder. In this work, features to detect sleep apnea events were computed from respiration and electrocardiogram recordings acquired with a wearable smart-shirt. First, a classical scheme exploiting the amplitude decrease of the respiration during apnea episodes was presented. Second, a novel measure of the phase coupling between the respiration and the respiratory sinus arrhythmia from the ECG was introduced. It was shown that these features were significantly different during sleep apnea episodes than for normal breathing.

Saugy, Jonas J., Laurent Schmitt, Sibylle Fallet, Raphael Faiss, Jean-Marc Vesin, Mattia Bertschi, Raphael Heinzer, and Gregoire P. Millet. Sleep disordered breathing during live high-train low in normobaric versus hypobaric hypoxia. High Alt Med Biol. 17:233–238, 2016.—The present study aimed to compare sleep disordered breathing during live high-train low (LHTL) altitude camp using normobaric hypoxia (NH) and hypobaric hypoxia (HH). Sixteen highly trained triathletes completed two 18-day LHTL camps in a crossover designed study. They trained at 1100–1200 m while they slept either in NH at a simulated altitude of 2250 m or in HH. Breathing frequency and oxygen saturation (SpO2) were recorded continuously during all nights and oxygen desaturation index (ODI 3%) calculated. Breathing frequency was lower for NH than HH during the camps (14.6 ± 3.1 breath × min−1 vs. 17.2 ± 3.4 breath × min−1, p