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The host immune response plays a critical role in the immunopathology of SARS-CoV2. Here the authors combine a systems biology approach to implicate monocytes as key drivers of cytokine storm and disturbed neutrophil activation in COVID-19 disease severity.

Wearable electroencephalography devices emerge as a cost-effective and ergonomic alternative to gold-standard polysomnography, paving the way for better health monitoring and sleep disorder screening. Machine learning allows to automate sleep stage classification, but trust and reliability issues have hampered its adoption in clinical applications. Estimating uncertainty is a crucial factor in enhancing reliability by identifying regions of heightened and diminished confidence. In this study, we used an uncertainty-centred machine learning pipeline, U-PASS, to automate sleep staging in a challenging real-world dataset of single-channel electroencephalography and accelerometry collected with a wearable device from an elderly population. We were able to effectively limit the uncertainty of our machine learning model and to reliably inform clinical experts of which predictions were uncertain to improve the machine learning model's reliability. This increased the five-stage sleep-scoring accuracy of a state-of-the-art machine learning model from 63.9% to 71.2% on our dataset. Remarkably, the machine learning approach outperformed the human expert in interpreting these wearable data. Manual review by sleep specialists, without specific training for sleep staging on wearable electroencephalography, proved ineffective. The clinical utility of this automated remote monitoring system was also demonstrated, establishing a strong correlation between the predicted sleep parameters and the reference polysomnography parameters, and reproducing known correlations with the apnea-hypopnea index. In essence, this work presents a promising avenue to revolutionize remote patient care through the power of machine learning by the use of an automated data-processing pipeline enhanced with uncertainty estimation., (© 2024 European Sleep Research Society.)

Obstructive sleep apnea increases morbidity and mortality risks. The most common treatment is continuous positive airway pressure, with nasal mask usage being important, but not always optimal. While most research on treatment adherence focuses on the patient, the bed partner's involvement may be detrimental. Our study aim is to obtain a European-wide picture of the bed partner's attitude and support towards continuous positive airway pressure therapy, including effects on relationship satisfaction and intimacy. The English translation of a German bed partner questionnaire, assessing relationship satisfaction and three major components (general attitude, perceived mask looks, intimacy effects) was distributed within the European Sleep Apnea Database Network and translated in participating countries' local language. Data were collected for 2 years. In total, 10 European countries (13 sleep centres) participated with 1546 questionnaires. Overall, 91% of bed partners had a positive attitude towards continuous positive airway pressure therapy, 86% perceived mask looks not negative, 64% stated no negative intimacy effects. More specifically, 71% mentioned improved sleep quality, 68% supported nightly device usage. For 41% of bed partners, relationship satisfaction increased (no change for 47%). These results were significantly more pronounced in Eastern/Southern Europe compared with Middle Europe, especially regarding intimacy effects. However, increased continuous positive airway pressure therapy length affected attitude negatively. These results provide necessary information to improve treatment strategies by including educational couple-focused approaches. Among others, we revealed that negative intimacy effects are not considered a barrier to continuous positive airway pressure adherence. These results may inspire more research identifying regional gaps with need for treatment adjustments., (© 2023 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

Both sleep alterations and epileptiform activity are associated with the accumulation of amyloid-β and tau pathology and are currently investigated for potential therapeutic interventions in Alzheimer's disease (AD). However, a bidirectional intertwining relation between sleep and neuronal hyperexcitability might modulate the effects of AD pathology on the corresponding associations. To investigate this, we performed multiple day simultaneous foramen ovale (FO) plus scalp EEG and polysomnography (PSG) recordings and acquired 18F-MK6240 tau PET-MR in three patients in the prodromal stage of AD and in two patients with mild and moderate dementia due to AD, respectively. As an eligibility criterion for the present study, subjects either had a history of a recent seizure (n = 2) or subclinical epileptiform activity (SEA) on a previous scalp EEG taken in a research context (n = 3). The 18F-MK6240 standard uptake value ratio (SUVR) and asymmetry index (AI) were calculated in a priori defined volumes of interest (VOIs). Linear mixed effects models were used to study associations between interictal epileptiform discharges (IEDs), PSG parameters and 18F-MK6240 SUVR. Epileptiform activity was bilateral but asymmetrically present on FO electrodes in all patients and ≥ 95% of IEDs were not visible on scalp EEG. In one patient two focal seizures were detected on FO electrodes, both without visual scalp EEG correlate. We observed lateralized periodic discharges, brief potentially ictal rhythmic discharges and lateralized rhythmic delta activity on FO electrodes in four patients. Unlike scalp EEG, intracranial electrodes showed a lateralization of epileptiform activity. Although the amount of IEDs on intracranial electrodes was not associated to the 18F-MK6240 SUVR binding in different VOIs, there was a congruent asymmetry of the 18F-MK6240 binding towards the most epileptic hemisphere for the mesial (P = 0.007) and lateral temporal cortex (P = 0.006). IEDs on intracranial electrodes were most abundant during slow wave sleep (SWS) (92/h) and N2 (81/h), followed by N1 (33/h) and least frequent during wakefulness (17/h) and REM sleep (9/h). The extent of IEDs during sleep was not reflected in the relative time in each sleep stage spent (REM% (P = 0.415), N1% (P = 0.668), N2% (P = 0.442), SWS% (P = 0.988)), and not associated with the arousal index (P = 0.317), apnea-hypopnea index (P = 0.846) or oxygen desaturation index (P = 0.746). Together, our observations suggest a multi-directional interaction between sleep, epileptiform activity and tau pathology in AD., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Objectives: To investigate the efficacy of closed-loop acoustic stimulation (CLAS) during slow-wave sleep (SWS) to enhance slow-wave activity (SWA) and SWS in patients with Alzheimer's disease (AD) across multiple nights and to explore associations between stimulation, participant characteristics, and individuals' SWS response., Design: A 2-week, open-label at-home intervention study utilizing the DREEM2 headband to record sleep data and administer CLAS during SWS., Setting and Participants: Fifteen older patients with AD (6 women, mean age: 76.27 [SD = 6.06], mean MOCA-score: 16.07 [SD = 6.94]), living at home with their partner, completed the trial., Intervention: Patients first wore the device for two baseline nights, followed by 14 nights during which the device was programmed to randomly either deliver acoustic stimulations of 50 ms pink noise (± 40 dB) targeted to the slow-wave up-phase during SWS or only mark the wave (sham)., Results: On a group level, stimulation significantly enhanced SWA and SWS with consistent SWS enhancement throughout the intervention. However, substantial variability existed in individual responses to stimulation. Individuals received more stimulations on nights with increased SWS compared to baseline than on nights with no change or a decrease. In individuals, having lower baseline SWS correlated with receiving fewer stimulations on average during the intervention., Conclusion: CLAS during SWS is a promising nonpharmacological method to enhance SWA and SWS in AD. However, patients with lower baseline SWS received fewer stimulations during the intervention, possibly resulting in less SWS enhancement. Individual variability in response to stimulation underscores the need to address personalized stimulation parameters in future research and therapy development., Competing Interests: DISCLOSURE The authors report no conflicts with any product mentioned or concept discussed in this article., (Copyright © 2024. Published by Elsevier Inc.)

Introduction: Central sleep apnea (CSA) is a sleep-related breathing disorder in which the effort to breathe is intermittently diminished or absent. CSA is a common disorder among patients with different cardiovascular disorders, including heart failure. In addition, a growing number of medications have been shown to induce CSA and CSA can emerge after initiation of treatment for obstructive sleep apnea. Accumulating evidence shows that CSA is a heterogeneous disorder with individual differences in clinical and biological characteristics and/or underlying pathophysiological mechanisms., Areas Covered: This narrative review offers an overview of the diagnostic aspects and classification of CSA, with an emphasis on heart failure patients, patients with CSA due to a medication and treatment-emergent CSA. The importance of evaluation of prognostic biomarkers in patients with different types of CSA is discussed. This narrative review synthesizes literature on CSA sourced from the PubMed database up to February 2024., Expert Opinion: CSA presents a remarkably diverse disorder, with treatment modalities exhibiting potentially varied efficacy across its various phenotypes. This highlights the imperative for tailored management strategies that are rooted in phenotype classification.

Objectives: In psychogeriatric units for patients with dementia and behavioral problems, aggression is prevalent. Predictions and timely interventions of aggression are essential to create a safe environment and prevent adverse outcomes. Our study aimed to determine whether aggression severity early during admission to these units could be used as an indicator of adverse outcomes., Design: During one year, all aggressive incidents on a psychogeriatric unit were systematically recorded using the Revised Staff Observation of Aggression Scale (SOAS-R). The study investigated the link between the severity of incidents within the first 48 hours of admission and adverse outcomes., Setting and Participants: All patients included in the study were admitted to a psychogeriatric unit for dementia and behavioral problems between November 2020 and October 2021., Methods: The study population was categorized into groups according to the level of aggression severity during the first 48 hours of admission. The impact of aggression severity on the duration of admission, aggression frequency and severity during admission, medication usage at discharge, discharge destination, and mortality risk were examined., Results: During the initial 2 days of admission, 9 of 88 patients had 1 or more severe aggression incidents. An early manifestation of severe aggression was significantly associated with more incidents during hospitalization, a higher total SOAS-R score, and a sevenfold higher 1-year mortality risk compared with patients who did not or only mildly manifested aggression in the first 48 hours of admission., Conclusions and Implications: An early manifestation of aggression not only poses a direct safety risk to all involved but is also an early indicator of patients at risk for more detrimental outcomes, specifically mortality risk. By identifying patients at higher risk for adverse outcomes early, health care providers can provide preventive or timelier interventions, mitigating the risk of adverse outcomes and optimizing care services., Competing Interests: Disclosure The authors declare no conflicts of interest., (Copyright © 2023 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

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., (© 2023 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.)

The topic of sleep-related breathing disorders is always evolving, and during the European Respiratory Society (ERS) International Congress 2023 in Milan, Italy, the latest research and clinical topics in respiratory medicine were presented. The most interesting issues included new diagnostic tools, such as cardiovascular parameters and artificial intelligence, pathophysiological traits of sleep disordered breathing from routine polysomnography or polygraphy signals, and new biomarkers and the diagnostic approach in patients with excessive daytime sleepiness. This article summarises the most relevant studies and topics presented at the ERS International Congress 2023. Each section has been written by early career members of ERS Assembly 4., Competing Interests: Conflict of interest: M. Bradicich reports an ERS faculty participation grant for the ERS International Congress 2023, outside the submitted work; payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from ERS faculty participation grant for the ERS International Congress 2023, outside the submitted work; support for attending meetings and/or travel from ERS faculty participation grant for the ERS International Congress 2023, outside the submitted work; and is ERS ECMC Representative for Assembly 4, outside the submitted work. Conflict of interest: D. Testelmans reports payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from Resmed and Nyxoah, outside the submitted work. Conflict of interest: M. Sánchez-de-la-Torre reports grants or contracts from Instituto de Salud Carlos III (Spain Goverment), outside the submitted work; payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from Jazz Pharmaceuticals and Philips, outside the submitted work; and support for attending meetings and/or travel from Jazz Pharmaceuticals and Resmed, outside the submitted work. Conflict of interest: W. Randerath is an associate editor of this journal. Conflict of interest: E.I. Schwarz reports grants or contracts from Philips Respironics, Löwenstein and the Swiss National Science Foundation, outside the submitted work; payment or honorara for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from ResMed, outside the submitted work; leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid for ERS Secretary of Assembly 4, outside the submitted work. Conflict of interest: S. Schiza reports being ERS secretary of Assembly 4 (until September 2023), unpaid, outside the submitted work. Conflict of interest: The remaining authors have nothing to disclose., (Copyright ©The authors 2024.)

With the increasing prevalence of machine learning in critical fields like healthcare, ensuring the safety and reliability of these systems is crucial. Estimating uncertainty plays a vital role in enhancing reliability by identifying areas of high and low confidence and reducing the risk of errors. This study introduces U-PASS, a specialized human-centered machine learning pipeline tailored for clinical applications, which effectively communicates uncertainty to clinical experts and collaborates with them to improve predictions. U-PASS incorporates uncertainty estimation at every stage of the process, including data acquisition, training, and model deployment. Training is divided into a supervised pre-training step and a semi-supervised recording-wise finetuning step. We apply U-PASS to the challenging task of sleep staging and demonstrate that it systematically improves performance at every stage. By optimizing the training dataset, actively seeking feedback from domain experts for informative samples, and deferring the most uncertain samples to experts, U-PASS achieves an impressive expert-level accuracy of 85% on a challenging clinical dataset of elderly sleep apnea patients. This represents a significant improvement over the starting point at 75% accuracy. The largest improvement gain is due to the deferral of uncertain epochs to a sleep expert. U-PASS presents a promising AI approach to incorporating uncertainty estimation in machine learning pipelines, improving their reliability and unlocking their potential in clinical settings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Study Objectives: Sleep disturbances are common in people with Alzheimer's disease (AD), and a reduction in slow-wave activity is the most striking underlying change. Acoustic stimulation has emerged as a promising approach to enhance slow-wave activity in healthy adults and people with amnestic mild cognitive impairment. In this phase 1 study we investigated, for the first time, the feasibility of acoustic stimulation in AD and piloted the effect on slow-wave sleep (SWS)., Methods: Eleven adults with mild to moderate AD first wore the DREEM 2 headband for 2 nights to establish a baseline registration. Using machine learning, the DREEM 2 headband automatically scores sleep stages in real time. Subsequently, the participants wore the headband for 14 consecutive "stimulation nights" at home. During these nights, the device applied phase-locked acoustic stimulation of 40-dB pink noise delivered over 2 bone-conductance transducers targeted to the up-phase of the delta wave or SHAM, if it detected SWS in sufficiently high-quality data., Results: Results of the DREEM 2 headband algorithm show a significant average increase in SWS (minutes) [ t (3.17) = 33.57, P = .019] between the beginning and end of the intervention, almost twice as much time was spent in SWS. Consensus scoring of electroencephalography data confirmed this trend of more time spent in SWS [ t (2.4) = 26.07, P = .053]., Conclusions: Our phase 1 study provided the first evidence that targeted acoustic stimuli is feasible and could increase SWS in AD significantly. Future studies should further test and optimize the effect of stimulation on SWS in AD in a large randomized controlled trial., Citation: Van den Bulcke L, Peeters A-M, Heremans E, et al. Acoustic stimulation as a promising technique to enhance slow-wave sleep in Alzheimer's disease: results of a pilot study. J Clin Sleep Med . 2023;19(12):2107-2112., (© 2023 American Academy of Sleep Medicine.)

Study Objectives: Catathrenia, derived from the Greek κατά (kata) meaning below and θρηνώ (threnia) to lament, is characterized by expiratory groaning episodes during sleep. In a case series of nine patients with severe obstructive sleep apnea, we observed a peculiar groaning entity that has not been described before., Methods: We described and illustrated the cases with polysomnographic tracings and additional audio recordings., Results: All patients were men, obese (body mass index 39 ± 6 kg/m 2 ) with an apnea-hypopnea index ranging from 47 to 125/h. In addition, we identified groaning events that were consistently preceded by a cortical arousal associated with a "rescue" respiration after an obstructive hypopnea or apnea. These events exhibited characteristics of "mixed apnea's", but the "central apnea-like part" was a prolonged expiratory groaning phase, with immediately after the terminal expiratory snort appearance of an obstructive apnea. In case the duration of this expiration was at least 10 s we calculated these events separately and the index was 8.4 ± 7.7/h. More rarely (index 0.6 ± 0.5/h) a "central apnea mimicking event" with groaning not followed by an obstruction, was observed. We also observed groaning episodes during expiration with a shorter duration (less than 10 s), not calculated separately. Positive airway pressure, which was well tolerated, eliminated these events., Conclusions: This novel catathrenia entity preceded by a cortical arousal and "rescue" respiration in response to obstructive events is intriguing. Possible explanations for these observations are further discussed in this article., Competing Interests: Declaration of competing interest This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Introduction: Subclinical epileptiform activity (SEA) and sleep disturbances are frequent in Alzheimer's disease (AD). Both have an important relation to cognition and potential therapeutic implications. We aimed to study a possible relationship between SEA and sleep disturbances in AD., Methods: In this cross-sectional study, we performed a 24-h ambulatory EEG and polysomnography in 48 AD patients without diagnosis of epilepsy and 34 control subjects., Results: SEA, mainly detected in frontotemporal brain regions during N2 with a median of three spikes/night [IQR1-17], was three times more prevalent in AD. AD patients had lower sleep efficacy, longer wake after sleep onset, more awakenings, more N1%, less REM sleep and a higher apnea-hypopnea index (AHI) and oxygen desaturation index (ODI). Sleep was not different between AD subgroup with SEA (AD-Epi+) and without SEA (AD-Epi-); however, compared to controls, REM% was decreased and AHI and ODI were increased in the AD-Epi+ subgroup., Discussion: Decreased REM sleep and more severe sleep-disordered breathing might be related to SEA in AD. These results could have diagnostic and therapeutic implications and warrant further study at the intersection between sleep and epileptiform activity in AD., (© 2023 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)

Obstructive sleep apnea (OSA) is a high-prevalence disease in the general population, often underdiagnosed. The gold standard in clinical practice for its diagnosis and severity assessment is the polysomnography, although in-home approaches have been proposed in recent years to overcome its limitations. Today's ubiquitously presence of wearables may become a powerful screening tool in the general population and pulse-oximetry-based techniques could be used for early OSA diagnosis. In this work, the peripheral oxygen saturation together with the pulse-to-pulse interval (PPI) series derived from photoplethysmography (PPG) are used as inputs for OSA diagnosis. Different models are trained to classify between normal and abnormal breathing segments (binary decision), and between normal, apneic and hypopneic segments (multiclass decision). The models obtained 86.27% and 73.07% accuracy for the binary and multiclass segment classification, respectively. A novel index, the cyclic variation of the heart rate index (CVHRI), derived from PPI's spectrum, is computed on the segments containing disturbed breathing, representing the frequency of the events. CVHRI showed strong Pearson's correlation (r) with the apnea-hypopnea index (AHI) both after binary (r=0.94, p 0.001) and multiclass (r=0.91, p 0.001) segment classification. In addition, CVHRI has been used to stratify subjects with AHI higher/lower than a threshold of 5 and 15, resulting in 77.27% and 79.55% accuracy, respectively. In conclusion, patient stratification based on the combination of oxygen saturation and PPI analysis, with the addition of CVHRI, is a suitable, wearable friendly and low-cost tool for OSA screening at home.

One fifth of today's workforce is engaged in shift work and exposed to various mental and physical health risks including shift work disorder. Efficiently recovering from shift work through physical and mental interventions allows us to mitigate negative effects on health, enables a better work-life balance and enhances our overall wellbeing. The aim of this review is to provide a state-of-the-art overview of the available literature. The role of sleep timing and naps, light therapy and psychotherapy, diet and exercise in recovery from shift work is presented here. We further review the impact of shift schedules and social support on post-shift unwinding., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kalkanis, Demolder, Papadopoulos, Testelmans and Buyse.)

Aims: We analysed longitudinal blood pressure (BP) data from hypertensive obstructive sleep apnoea (OSA) patients in the European Sleep Apnea Database cohort. The study investigated the interaction between positive airway pressure (PAP)-induced BP change and antihypertensive treatment (AHT)., Methods and Results: Hypertensive patients with AHT [monotherapy/dual therapy n = 1283/652, mean age 59.6 ± 10.7/60.6 ± 10.3 years, body mass index (BMI) 34.2 ± 6.5/34.8 ± 7.0 kg/m 2 , apnoea-hypopnoea index 46 ± 25/46 ± 24 n/h, proportion female 29/26%, respectively] started PAP treatment. Office BP at baseline and 2- to 36-month follow-up were assessed. The interaction between AHT drug classes and PAP on BP was quantified and the influences of age, gender, BMI, co-morbidities, BP at baseline, and study site were evaluated. Following PAP treatment (daily usage, 5.6 ± 1.6/5.7 ± 1.9 h/day), systolic BP was reduced by -3.9 ± 15.5/-2.8 ± 17.7 mmHg in mono/dual AHT and diastolic BP by -3.0 ± 9.8/-2.7 ± 10.8 mmHg, respectively, all P < 0.0001. Systolic and diastolic BP control was improved following PAP treatment (38/35% to 54/46% and 67/67% to 79/74%, mono/dual AHT, respectively). PAP treatment duration predicted a larger BP improvement in the monotherapy group. Intake of renin-angiotensin blockers [angiotensin converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB)] alone or in any AHT combination was associated with better BP control. The AHT-dependent BP improvement was independent of confounders., Conclusion: In this pan-European OSA patient cohort, BP control improved following initiation of PAP. Longer PAP treatment duration, was associated with a favourable effect on BP. Our study suggests that ACEI/ARB, alone or in combination with other drug classes, provides a particularly strong reduction of BP and better BP control when combined with PAP in OSA., Competing Interests: Conflict of interest: The ESADA study group received unrestricted funding grants from Respironics and Resmed Foundations (2008–11) and an unrestricted collaboration grant from Bayer AG (2018–22). S.S., corresponding author, reports no COI. He has grants from the Swedish Heart and Lung Foundation. J.H. reports no COI related to the content of the manuscript. He has institutional grants from Gothenburg University, Swedish Government Research and Educational grant LUA/ALF and grants from the Swedish Heart and Lung Foundation. Outside of the current manuscript, he has EU grants Horizon 2020, Eureka, and Inter Funding: Sleep Across Waters. He has consulting fees from SomnoMed (advisory input), has received research equipment from Itamar, and owns stock in Cereus Pharma. S.B. reports no COI. F.F. reports no COI. H.H. reports no COI. C.L. reports no COI. O.L. reports no COI. S.M. reports no COI. G.P. reports no COI; he has honoraria for lectures from Merck. A.P. reports no COI. S.S. reports no COI. S.T. reports no COI. D.T. reports no COI; he has payment to his Institution for lectures from Nyxoah. D.Z. reports no COI. L.G. reports no COI related to the content of the manuscript. He has institutional grants from LUA/ALF and the Swedish Heart and Lung Foundation. Outside the current manuscript, he provided lectures for Resmed, Philips, Astra Zeneca, and Lundbeck; and he has ownership in a patent licensed to Desitin GMBH related to sleep apnoea therapy., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Unilateral diaphragm dysfunction (UDD) is an underdiagnosed cause of dyspnoea. Inspiratory muscle training (IMT) is the only conservative treatment for UDD, but the mechanisms of improvement are unknown. We characterised the effects of IMT on dyspnoea, exercise tolerance and respiratory muscle function in people with UDD., Methods: 15 people with UDD (73% male, 61±8 years) were randomised to 6 months of IMT (50% maximal inspiratory mouth pressure ( P I,max ), n=10) or sham training (10% P I,max , n=5) (30 breaths twice per day). UDD was confirmed by phrenic nerve stimulation and persisted throughout the training period. Symptoms were assessed by the transitional dyspnoea index (TDI) and exercise tolerance by constant-load cycle tests performed pre- and post-training. Oesophageal ( P es ) and gastric ( P ga ) pressures were measured with a dual-balloon catheter. Electromyography (EMG) and oxygenation (near-infrared spectroscopy) of respiratory muscles were assessed continuously during exercise., Results: The IMT group (from 45±6 to 62±23% P I,max ) and sham group (no progression) completed 92 and 86% of prescribed sessions, respectively. P I,max , TDI scores and cycle endurance time improved significantly more after IMT versus sham (mean between-group differences: 28 (95% CI 13-28) cmH 2 O, 3.0 (95% CI 0.9-5.1) points and 6.0 (95% CI 0.4-11.5) min, respectively). During exercise at iso-time, P es , P ga and EMG of the scalene muscles were reduced and the oxygen saturation indices of the scalene and abdominal muscles were higher post- versus pre-training only in the IMT group (all p<0.05)., Conclusion: The effects of IMT on dyspnoea and exercise tolerance in UDD were not mediated by an improvement in isolated diaphragm function, but may reflect improvements in strength, coordination and/or oxygenation of the extra-diaphragmatic respiratory muscles., Competing Interests: Conflict of interest: Training devices were provided on loan for the study duration by HaB International Ltd. R. Gosselink reports personal fees from Elsevier. D. Langer reports a grant from Research Foundation Flanders and a leadership role with the European Respiratory Society. M.R. Schaeffer, Z. Louvaris, A. Rodrigues, D. Poddighe, G. Gayan-Ramirez, T. Gojevic, L. Geerts, E. Heyndrickx, M. Van Hollebeke, L. Janssens and D. Testelmans do not have any disclosures., (Copyright ©The authors 2023.)

The present study aimed to evaluate whether titration of fixed continuous positive airway pressure at home using telemonitoring produces patient outcomes equal to auto-adjusting positive airway pressure titration at home for patients with moderate obstructive sleep apnea. Patients were randomized with a 1:1 allocation ratio to receive either auto-adjusting positive airway pressure titration based on the median of the 95th percentile pressure across seven nights or fixed continuous positive airway pressure titration based on a fixed calculated pressure and specific adaptations after telemonitoring of device data after 3 and 7 nights. The results of the ambulatory titration were evaluated with in-laboratory polysomnography after 2 weeks. We hypothesized that fixed continuous positive airway pressure titration would be non-inferior to auto-adjusting positive airway pressure titration in respect to continuous positive airway pressure adherence at a 3-month follow-up. A non-inferiority margin of -0.75 hr was prespecified. One-hundred and four patients were randomly allocated to fixed continuous positive airway pressure (n = 52) and auto-adjusting positive airway pressure (n = 52) titration. The mean difference and the 95% confidence intervals in continuous positive airway pressure adherence after 3 months between the two arms were 0.80 (-0.08, 1.69) hr. The non-inferiority hypothesis was confirmed as the lower one-sided 97.5% confidence interval for the mean difference was above the prespecified margin. Patients in the fixed continuous positive airway pressure titration arm were titrated at significantly lower pressure level and had a significantly lower amount of average leaks compared with auto-adjusting positive airway pressure-titrated patients, while there was no difference in residual obstructive apnea-hypopnea index on polysomnography. Telemonitoring enables ambulatory continuous positive airway pressure titration with fixed pressure that is non-inferior to ambulatory titration with auto-adjusting pressure in patients with moderate obstructive sleep apnea., (© 2023 European Sleep Research Society.)

This paper presents some of the highlights of the Sleep and Breathing Conference 2023 https://bit.ly/46MxJml., Competing Interests: Conflict of interest: M. Bradicich reports receiving support to attend meetings and/or travel from the European Respiratory Society as an ERS officer and ERS International Congress faculty; and is the early career member representative of ERS Assembly 4, disclosure made outside the submitted work. W. Randerath reports payment or honoraria for lectures, presentations, speakers’ bureaus, manuscript writing or educational events from Heinen & Löwenstein, Philips Respironics, and Habel Medizintechnik, outside the submitted work; and is Head of ERS Assembly 4, Sleep Disordered Breathing (unpaid position) and the German Respiratory Society Secretary General (unpaid position), disclosures made outside the submitted work. J. Cruz is the early career member representative of ERS Assembly 9, disclosure made outside the submitted work. The remaining authors have nothing to disclose., (Copyright ©ERS 2023.)

Obstructive sleep apnea (OSA) is a sleeping disorder caused by complete or partial disturbance of breathing during the night. Existing screening methods include questionnaire-based evaluations which are time-consuming, vary in specificity, and are not globally adopted. Point-of-care ultrasound (PoCUS), on the other hand, is a painless, inexpensive, portable, and useful tool that has already been introduced for the evaluation of upper airways by anesthetists. PoCUS could also serve as a potential screening tool for the diagnosis of OSA by measuring different airway parameters, including retropalatal pharynx transverse diameter, tongue base thickness, distance between lingual arteries, lateral parapharyngeal wall thickness, palatine tonsil volume, and some non-airway parameters like carotid intima-media thickness, mesenteric fat thickness, and diaphragm characteristics. This study reviewed previously reported studies to highlight the importance of PoCUS as a potential screening tool for OSA.

During the European Respiratory Society (ERS) International Congress 2022 in Barcelona, Spain, the latest research and clinical topics in respiratory medicine were presented. The sleep medicine-focused presentations and symposia provided novel insights into the pathophysiology of sleep disordered breathing, its diagnostics, and new trends in translational research and clinical applications. The presented research trends focused mainly on the assessment of sleep disordered breathing-related intermittent hypoxia, inflammation and sleep fragmentation, and their implications, especially cardiovascular. The most promising methods for assessing these aspects encompass genomics, proteomics and cluster analysis. The currently available options include positive airway pressure and a combination of it and pharmacological agents ( e.g. sulthiame). This article summarises the most relevant studies and topics on these subjects presented at the ERS International Congress 2022. Each section has been written by Early Career Members of the ERS Assembly 4., Competing Interests: Conflict of interest: M. Bradicich declares support from the European Respiratory Society for acting as faculty at the society's 2022 International Congress; and an unpaid role as Early Career Member Representative for European Respiratory Society Assembly 4 (Sleep Disordered Breathing). W. Randerath declares payment or honoraria from Heinen & Löwenstein, Resmed, Jazz Pharmaceuticals, Inspire, Philips Respironics, Bioprojet and Westfalen Medical; support for attending meetings and/or travel from Heinen & Löwenstein, Jazz Pharmaceuticals, Philips Respironics and Bioprojet; and participation on a data safety monitoring or advisory board from Bioprojet, Jazz Pharmaceuticals, Philips Respironics and Procter & Gamble, all in the 36 months prior to manuscript submission; as well as an unpaid role as head of European Respiratory Society Assembly 4 (Sleep Disordered Breathing). He is an associate editor of this journal. All other authors declare no competing interests., (Copyright ©The authors 2023.)

The American Academy of Sleep Medicine (AASM) uses similar apnea-hypopnea index (AHI) cut-off values to diagnose and define severity of sleep apnea independent of the technique used: in-hospital polysomnography (PSG) or type 3 portable monitoring (PM). Taking into account that PM theoretically might underestimate the AHI, we explored whether a lower cut-off would be more appropriate. We performed mathematical re-calculations on the diagnostic PSG-AHI (scored using AASM 1999 rules) of 865 consecutive patients with an AHI of ≥20 events/h who started continuous positive airway pressure (CPAP). For a PSG-AHI of ≥15 events/h re-scored using AASM 2012 rules (PSG-AHI AASM2012 ), a PM-respiratory event index (REI) AASM2012 cut-off point of ≥15 events/h resulted in a post-test probability of 100% of having the disease, but with negative tests in 57.1%. A PM-REI AASM2012 cut-off of 8 events/h, still resulted in a positive post-test probability of 100% but with negative tests in only 34.3%. Combination of the cut-off values with clinical estimation of being 'at high risk' based on Epworth Sleepiness Scale (ESS) and Berlin Questionnaire scores only resulted in a small reduction in the percentage of negative tests (respectively 52.7% and 32.7%). After 6 months, CPAP adherence was not lower using the PM-REI AASM 2012 cut-off ≥8 events/h in comparison to ≥15 events/h (median 5.7 vs. 5.8 h/night, p = 0.368) and the reduction in ESS was similar too (median -4 and -5 points, p = 0.083). Consequently, using a lower PM-REI AASM2012 cut-off could result in cost savings because of less negative studies and lesser need for a confirmatory PSG or a performance of a CPAP trial., (© 2022 European Sleep Research Society.)

For more than three decades, type III devices have been used in the diagnosis of sleep disordered breathing in supervised as well as unsupervised settings. They have satisfactory positive and negative predictive values for detecting obstructive and central sleep apnoea in populations with moderately high pre-test probability of symptoms associated with these events. However, standardisation of commercially available type III devices has never been undertaken and the technical specifications can vary widely. None have been subjected to the same rigorous processes as most other diagnostic modalities in the medical field. Although type III devices do not include acquisition of electroencephalographic signals overnight, the minimum number of physical sensors required to allow for respiratory event scoring using standards outlined by the American Academy of Sleep Medicine remains debatable. This technical standard summarises data on type III studies published since 2007 from multiple perspectives in both adult and paediatric sleep practice. Most importantly, it aims to provide a framework for considering current type III device limitations in the diagnosis of sleep disordered breathing while raising research- and practice-related questions aimed at improving our use of these devices in the present and future., Competing Interests: Conflict of interest: T. Penzel reports personal speaker fees from Cerebra, Jazz Pharma, Löwenstein Medical, National Sleep Foundation and Neuwirth; consulting fees from Bayer Healthcare and Cerebra; travel support from Jazz Pharma and Nukute; participation on advisory boards for Nukute and Cerebra; stock or stock options with The Siestagroup, Nukute and Advanced Sleep Research; receipt of equipment from Neurovirtual; institutional fees and research grants from Bayer Healthcare, Cidelec, Löwenstein Medical, Novartis and Springer Publisher. T. Penzel also reports the following leadership roles: German Sleep Society (president, unpaid), IEEE Engineering in Medicine and Biology (advisory committee member, unpaid), German Society on Biomedical Engineering (board member, unpaid), DIN – German standardization body (committee member, unpaid). W. Randerath reports institutional fees, research grants and speaking fees from Philips Respironics, Heinen & Löwenstein, Jazz Pharmaceuticals, Weinmann, Resmed, Inspire, Vanda Pharma and Bioprojet, and is head of European Respiratory Society assembly 4 (Sleep Disordered Breathing). R.L. Riha reports one-off personal speaker fees and participation on an advisory board from Jazz Pharmaceuticals, and is also co-director of Sleep Consultancy Ltd. D. Testelmans reports institutional fees and educational grants from AirLiquide, Philips Respironics and Resmed. J. Verbraecken reports institutional fees and educational grants from Accuramed, Agfa-Gevaert, AirLiquide, AstraZeneca, Bekaert Deslee Academy, Bioprojet, Desitin, Ectosense, Fisher & Paykel, Heinen & Löwenstein, Idorsia, Inspire, Jazz Pharmaceutics, Medidis, Mediq Tefa, MSD, NightBalance, OSA Academy, OSG, Oxford Pharmagenesis, Philips Respironics, ResMed, Sanofi, SomnoMed, Springer, Total Care, UCB Pharma, Vivisol, Wave Medical and Westfalen Medical; consulting fees from Vermedia; and reports the following leadership roles: president (up to August 2021) and past president of the Belgian Association for Sleep research and Sleep medicine (since September 2021). M. Celmina reports lecture honoraria from Rare Diseases Conference and Latvian Medical Association; support to attend various conferences (IPSA, Baltic Sleep Meeting, Nordic Sleep Meeting) provided by Children's Clinical University Hospital (Riga, Latvia); and is a member of the board of the Latvian Sleep Medicine Society. A. Morley reports lecture honoraria from Sleep Consultancy Ltd and Sleep Scotland; participation on advisory board for the BTS Guideline for Pediatric Sleep Disorders; and is a board member of Association of Respiratory Technology and Physiology – Sleep. L. Roberti reports grants/funding to AAI ETS patient organisations from Resmed, Fisher & Paykel, Jazz Ph, Bioprojet, Vitalaire, Linde, Medicair, Philips, Olympus, Respiraire and Vivisol; and also reports the following leadership roles: President of Associazione Apnoici Italiani ETS (Italian Sleep Apnoea Patient Association), Sleep Apnoea Patient Representative of EMA, and Member of ELF Sleep Apnoea PAG. W. Ruehland reports travel support from Institute for Breathing and Sleep to attend Sleep Downunder and TSANZSRS Conferences, and from Australian and New Zealand Sleep Science Association to attend Sleep Downunder conference; and also reports the following leadership roles: board member of the Australian and New Zealand Sleep Science Association, committee member of the Medical and Scientific Research Committee, Institute for Breathing and Sleep, and is director of Respiratory Quality Assurance Pty Ltd, which provides PSG scoring external proficiency testing program (QSleep) for sleep centres. G. Grundström is Chairman of the Swedish Sleep Apnea Association. B. Cooper, R. Hamutcu-Ersu, A. Kaditis, A. Pataka and A. van Eyck have no conflict of interest to disclose related to the topic discussed in this technical standard., (Copyright ©The authors 2023. For reproduction rights and permissions contact permissions@ersnet.org.)

Study Objectives: To evaluate (determinants of) treatment success of mandibular advancement device application in a selected phenotype of patients with obstructive sleep apnea (OSA)., Methods: Ninety nonobese patients with moderate OSA (obstructive apnea-hypopnea index [OAHI] ≥ 15 and < 30 events/h) without comorbidities were prospectively included. Polysomnography was performed at baseline and with a mandibular advancement device. A drug-induced sleep endoscopy with jaw thrust was performed in 83%., Results: OAHI reduction ≥ 50% was observed in 73%, OAHI reduction ≥ 50% with OAHI < 10 events/h in 70%, and complete OSA resolution (OAHI < 5 events/h) in 40%. Patients with nonpositional OSA showed a significantly higher rate of complete OSA resolution: Posttest probability increased to 67%. In patients with total disappearance of collapse at velum level and at all levels during drug-induced sleep endoscopy with jaw thrust, the drop in OAHI was impressive with an infinitively high positive likelihood ratio. However, the proportion of patients having nonpositional OSA or the drug-induced sleep endoscopy characteristics as described above was < 20%. The change in snoring disturbance based on a visual analog scale was 76% (interquartile range 40-89%, P < .001) and a statistically significant amelioration in Epworth Sleepiness Scale (especially in somnolent subjects) was observed. High adherence was reported., Conclusions: In this predefined OSA phenotype, a mandibular advancement device was effective in reduction of OAHI and in amelioration of symptoms. Stratification by nonpositional OSA and findings on drug-induced sleep endoscopy with jaw thrust increased treatment success defined as reduction in OAHI. However, the clinical relevance can be questioned because only a small number of patients demonstrated these characteristics., Citation: Buyse B, Nguyen PAH, Leemans J, et al. Short-term positive effects of a mandibular advancement device in a selected phenotype of patients with moderate obstructive sleep apnea: a prospective study. J Clin Sleep Med . 2023;19(1):5-16., (© 2023 American Academy of Sleep Medicine.)

Lung cancer is considered one of the most fatal malignant neoplasms because of its late detection. Detecting molecular markers in samples from routine bronchoscopy, including many liquid-based cytology procedures, such as bronchoalveolar lavage fluid (BALF), could serve as a favorable technique to enhance the efficiency of a lung cancer diagnosis. BALF analysis is a promising approach to evaluating the tumor progression microenvironment. BALF's cellular and non-cellular components dictate the inflammatory response in a cancer-proliferating microenvironment. Furthermore, it is an essential material for detecting clinically significant predictive and prognostic biomarkers that may aid in guiding treatment choices and evaluating therapy-induced toxicities in lung cancer. In the present article, we have reviewed recent literature about the utility of BALF analysis for detecting markers in different stages of tumor cell metabolism, employing either specific biomarker assays or broader omics approaches.

Background: Immune checkpoint inhibitor (ICI)-related pneumonitis is the most frequent fatal immune-related adverse event associated with programmed cell death protein-1/programmed death ligand-1 blockade. The pathophysiology however remains largely unknown, owing to limited and contradictory findings in existing literature pointing at either T-helper 1 or T-helper 17-mediated autoimmunity. In this study, we aimed to gain novel insights into the mechanisms of ICI-related pneumonitis, thereby identifying potential therapeutic targets., Methods: In this prospective observational study, single-cell RNA and T-cell receptor sequencing was performed on bronchoalveolar lavage fluid of 11 patients with ICI-related pneumonitis and 6 demographically-matched patients with cancer without ICI-related pneumonitis. Single-cell transcriptomic immunophenotyping and cell fate mapping coupled to T-cell receptor repertoire analyses were performed., Results: We observed enrichment of both CD4+ and CD8+ T cells in ICI-pneumonitis bronchoalveolar lavage fluid. The CD4+ T-cell compartment showed an increase of pathogenic T-helper 17.1 cells, characterized by high co-expression of TBX21 (encoding T-bet) and RORC (ROR-γ), IFN-G (IFN-γ), IL-17A , CSF2 (GM-CSF), and cytotoxicity genes. Type 1 regulatory T cells and naïve-like CD4+ T cells were also enriched. Within the CD8+ T-cell compartment, mainly effector memory T cells were increased. Correspondingly, myeloid cells in ICI-pneumonitis bronchoalveolar lavage fluid were relatively depleted of anti-inflammatory resident alveolar macrophages while pro-inflammatory 'M1-like' monocytes (expressing TNF , IL-1B , IL-6 , IL-23A, and GM-CSF receptor CSF2RA, CSF2RB ) were enriched compared with control samples. Importantly, a feedforward loop, in which GM-CSF production by pathogenic T-helper 17.1 cells promotes tissue inflammation and IL-23 production by pro-inflammatory monocytes and vice versa, has been well characterized in multiple autoimmune disorders but has never been identified in ICI-related pneumonitis., Conclusions: Using single-cell transcriptomics, we identified accumulation of pathogenic T-helper 17.1 cells in ICI-pneumonitis bronchoalveolar lavage fluid-a phenotype explaining previous divergent findings on T-helper 1 versus T-helper 17 involvement in ICI-pneumonitis-,putatively engaging in detrimental crosstalk with pro-inflammatory 'M1-like' monocytes. This finding yields several novel potential therapeutic targets for the treatment of ICI-pneumonitis. Most notably repurposing anti-IL-23 merits further research as a potential efficacious and safe treatment for ICI-pneumonitis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: In 2010, a questionnaire-based study on obstructive sleep apnea (OSA) management in Europe identified differences regarding reimbursement, sleep specialist qualification, and titration procedures. Now, 10 years later, a follow-up study was conducted as part of the ESADA (European Sleep Apnea Database) network to explore the development of OSA management over time., Methods: The 2010 questionnaire including questions on sleep diagnostic, reimbursement, treatment, and certification was updated with questions on telemedicine and distributed to European Sleep Centers to reflect European OSA management practice., Results: 26 countries (36 sleep centers) participated, representing 20 ESADA and 6 non-ESADA countries. All 21 countries from the 2010 survey participated. In 2010, OSA diagnostic procedures were performed mainly by specialized physicians (86%), whereas now mainly by certified sleep specialists and specialized physicians (69%). Treatment and titration procedures are currently quite homogenous, with a strong trend towards more Autotitrating Positive Airway Pressure treatment (in hospital 73%, at home 62%). From 2010 to 2020, home sleep apnea testing use increased (76%-89%) and polysomnography as sole diagnostic procedure decreased (24%-12%). Availability of a sleep specialist qualification increased (52%-65%) as well as the number of certified polysomnography scorers (certified physicians: 36%-79%; certified technicians: 20%-62%). Telemedicine, not surveyed in 2010, is now in 2020 used in diagnostics (8%), treatment (50%), and follow-up (73%)., Conclusion: In the past decade, formal qualification of sleep center personnel increased, OSA diagnostic and treatment procedures shifted towards a more automatic approach, and telemedicine became more prominent., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In the past, there was limited research relating to the role of sleep in respiratory diseases. Physicians treating these patients tended to focus mainly on the daily disabling symptoms, overlooking the possible significant role of coexisting sleep disorders such as obstructive sleep apnoea (OSA). Nowadays, OSA has been recognised as an important, highly prevalent comorbidity for respiratory diseases such as COPD, asthma and interstitial lung diseases (ILDs). Overlap syndrome refers to the coexistence of chronic respiratory disease and OSA in the same patient. Although, in the past, overlap syndromes have been poorly studied, recent data underline that they result in increased morbidity and mortality compared with either underlying disorder alone. OSA and respiratory disease may be of different severity, and this, along with the existence of various clinical phenotypes, points to the necessity of an individualised therapeutic plan. Early recognition and OSA management could offer key benefits, such as improved sleep, quality of life and disease outcomes., Educational Aims: Describe pathophysiological aspects of OSA in chronic respiratory diseases such as COPD, asthma and ILDs.Understand the bidirectional clinical importance when OSA coexists in chronic respiratory diseases.Review current knowledge of treatment strategies towards an individualised therapeutic plan resulting in patient-centric outcomes., Competing Interests: Conflict of interest: All authors have no financial or other relationships and no conflict of interest to declare., (Copyright ©ERS 2022.)

While continuous positive airway pressure (CPAP) therapy has a strong evidence base for the treatment of obstructive sleep apnoea (OSA), its impact on cardiovascular comorbidity remains unclear. This journal club reviews three recent randomised controlled trials aimed to evaluate the impact of CPAP therapy in secondary prevention of cerebrovascular and coronary heart disease (SAVE trial), comorbid coronary heart disease (RICCADSA trial) and in patients admitted with acute coronary syndrome (ISAACC trial). All three trials included patients with moderate-to-severe OSA and excluded patients with severe daytime sleepiness. When CPAP was compared with usual care, they all reported no difference in a similar primary composite end-point including death from cardiovascular disease, cardiac events, and strokes. These trials faced the same methodological challenges, including a low primary end-point incidence, the exclusion of sleepy patients, and a low CPAP adherence. Therefore, caution must be taken when broadening their results to the wider OSA population. Although randomised controlled trials provide a high level of evidence, they may not be sufficient to capture the diversity of OSA. Large-scale, real-world data may be able to provide a more rounded and generalisable picture of the effects of routine clinical use of CPAP on cardiovascular morbimortality., Competing Interests: Conflicts of interest: The authors have no conflict of interest to declare., (Copyright ©ERS 2022.)

Objective. The recent breakthrough of wearable sleep monitoring devices has resulted in large amounts of sleep data. However, as limited labels are available, interpreting these data requires automated sleep stage classification methods with a small need for labeled training data. Transfer learning and domain adaptation offer possible solutions by enabling models to learn on a source dataset and adapt to a target dataset. Approach. In this paper, we investigate adversarial domain adaptation applied to real use cases with wearable sleep datasets acquired from diseased patient populations. Different practical aspects of the adversarial domain adaptation framework are examined, including the added value of (pseudo-)labels from the target dataset and the influence of domain mismatch between the source and target data. The method is also implemented for personalization to specific patients. Main results. The results show that adversarial domain adaptation is effective in the application of sleep staging on wearable data. When compared to a model applied on a target dataset without any adaptation, the domain adaptation method in its simplest form achieves relative gains of 7%-27% in accuracy. The performance in the target domain is further boosted by adding pseudo-labels and real target domain labels when available, and by choosing an appropriate source dataset. Furthermore, unsupervised adversarial domain adaptation can also personalize a model, improving the performance by 1%-2% compared to a non-personalized model. Significance. In conclusion, adversarial domain adaptation provides a flexible framework for semi-supervised and unsupervised transfer learning. This is particularly useful in sleep staging and other wearable electroencephalography applications. (Clinical trial registration number: S64190.)., (© 2022 IOP Publishing Ltd.)

Objectives: Continuous positive airway pressure (CPAP) is the 'gold standard' treatment for moderate-to-severe obstructive sleep apnea (OSA); adherence is an important issue. The aim of this paper is to review Belgian data on CPAP users and their adherence over a period of 11 years., Methods: Data delivered annually by the CPAP centers to the Belgian National Institute for Health Insurance (RIZIV/INAMI) were studied. Comments on these results were embedded in a narrative review., Results: On 1 January 2008 27.266 Belgian patients were treated with CPAP, at the end of 2018 this number increased to 121.605. In 2018, the short-term adherence (≤3 months) to CPAP was at least twice as high compared to the United States: the CPAP termination rate in Belgium (mainly due to stop of reimbursement because adherence <4 h/night) was estimated to be 12.4%, considerably lower than the 31.1% of patients on CPAP in the United States using the device <4 h., Conclusion: We speculate that this good adherence might be attributed to a stringent Belgian diagnostic and treatment convention model. This model uses 'gold standard' techniques (including in-hospital polysomnography), imposes a minimum capacity of medical doctors and paramedical collaborators, a strict follow-up of the patients, multidisciplinary care and proof of competency. Taking into account the increasing number of patients, a change in the Belgian care strategy is under consideration focusing on more out-of-centre patient's management; we propose a step-by step approach with careful monitoring of the impact of changing policy on adherence.

We conducted a prospective single-center observational study to determine lung ultrasound reliability in assessing global lung aeration in 38 hospitalized patients with non-critical COVID-19. On admission, fixed chest CT scans using visual (CTv) and software-based (CTs) analyses along with lung ultrasound imaging protocols and scoring systems were applied. The primary endpoint was the correlation between global chest CTs score and global lung ultrasound score. The secondary endpoint was the association between radiographic features and clinical disease classification or laboratory indices of inflammation. Bland−Altman analysis between chest CT scores obtained visually (CTv) or using software (CTs) indicated that only 1 of the 38 paired measures was outside the 95% limits of agreement (−4 to +4 score). Global lung ultrasound score was highly and positively correlated with global software-based CTs score (r = 0.74, CI = 0.55−0.86; p < 0.0001). Significantly higher median CTs score (p = 0.01) and lung ultrasound score (p = 0.02) were found in severe compared to moderate COVID-19. Furthermore, we identified significantly lower (p < 0.05) lung ultrasound and CTs scores in those patients with a more severe clinical condition manifested by SpO2 < 92% and C-reactive protein > 58 mg/L. We concluded that lung ultrasound is a reliable bedside clinical tool to assess global lung aeration in hospitalized non-critical care patients with COVID-19 pneumonia.

Purpose: Obstructive sleep apnea (OSA) is a prevalent and multifaceted disease. To date, the presence and severity of objectively identified comorbidities and their association with specific OSA phenotypes, CPAP adherence, and survival remain to be elucidated. The aim of this study is to cluster patients with OSA based on 10 clinically important objectively identified comorbidities, and to characterize the comorbidity clusters in terms of clinical and polysomnographic characteristics, CPAP adherence, and survival., Study Design and Methods: Seven hundred ten consecutive patients starting CPAP for moderate-to-severe OSA were included. Comorbidities were based on generally accepted cutoffs identified in the peer-reviewed literature. Self-organizing maps were used to order patients based on presence and severity of their comorbidities and to generate clusters., Results: The majority of patients were men (80%). They were generally middle-aged (52 years) and obese (BMI: 31.5 kg/m 2 ). Mean apnea-hypopnea index (AHI) was 41 ± 20 per h of sleep. More than 94% of the patients had one or more comorbidities with arterial hypertension, dyslipidemia, and obesity being the most prevalent. Nine comorbidity clusters were identified. The clinical relevance of these comorbidity clusters was highlighted by the difference in symptoms, PSG parameters, and cardiovascular risk. Also, differences in CPAP adherence, improvements in ESS, and long-term survival were present between the clusters., Conclusion: Comorbidity prevalence in patients with OSA is high, and different comorbidity clusters, demonstrating differences in cardiovascular risk, CPAP adherence, and survival, can be identified. These results further substantiate the need for a comprehensive assessment of patients with OSA beyond the AHI., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Rapid Eye Movement sleep behavior disorder (RBD) is a parasomnia causing sufferers to physically act out their dreams. These behaviors can disrupt sleep and sometimes lead to injuries in patients and their bed-partners. Clonazepam and melatonin are the first-line pharmacological treatment options for RBD based on direct uncontrolled clinical observations and very limited double-blind placebo-controlled trials. Given the risk for adverse outcomes, especially in older adults, it is of great importance to assess the existing level of evidence for the use of these treatments. In this update, we therefore critically review the clinical and scientific evidence on the pharmacological management of RBD in people aged over 50. We focus on the first-line treatments, and provide an overview of all other alternative pharmacological agents trialed for RBD we could locate as supplementary materials. By amalgamating all clinical observations, our update shows that 66.7% of 1,026 RBD patients reported improvements from clonazepam and 32.9% of 137 RBD patients reported improvements from melatonin treatment on various outcome measures in published accounts. Recently, however, three relatively small randomized placebo-controlled trials did not find these agents to be superior to placebo. Given clonazepam and melatonin are clinically assumed to majorly modify or eliminate RBD in nearly all patients-there is an urgent need to test whether this magnitude of treatment effect remains intact in larger placebo-controlled trials., (© 2021. The Author(s).)

Background. Respiratory sinus arrhythmia (RSA) is a form of cardiorespiratory coupling. Its quantification has been suggested as a biomarker to diagnose different diseases. Two state-of-the-art methods, based on subspace projections and entropy, are used to estimate the RSA strength and are evaluated in this paper. Their computation requires the selection of a model order, and their performance is strongly related to the temporal and spectral characteristics of the cardiorespiratory signals. Objective. To evaluate the robustness of the RSA estimates to the selection of model order, delays, changes of phase and irregular heartbeats as well as to give recommendations for their interpretation on each case. Approach. Simulations were used to evaluate the model order selection when calculating the RSA estimates introduced before, as well as three different scenarios that can occur in signals acquired in non-controlled environments and/or from patient populations: the presence of irregular heartbeats; the occurrence of delays between heart rate variability (HRV) and respiratory signals; and the changes over time of the phase between HRV and respiratory signals. Main results. It was found that using a single model order for all the calculations suffices to characterize RSA correctly. In addition, the RSA estimation in signals containing more than 5 irregular heartbeats in a period of 5 min might be misleading. Regarding the delays between HRV and respiratory signals, both estimates are robust. For the last scenario, the two approaches tolerate phase changes up to 54°, as long as this lasts less than one fifth of the recording duration. Significance. Guidelines are given to compute the RSA estimates in non-controlled environments and patient populations., (© 2021 Institute of Physics and Engineering in Medicine.)

Objective: SARS CoV-2 is an epidemic viral infection that can cause mild to severe lung involvement. Newly apprehended knowledge on thoracic imaging abnormalities and the growing clinical experience on the evolution of this disease make the radiographic follow-up of hospitalized patients relevant. The value of consecutive bedside lung ultrasonography in the follow-up of hospitalized patients with SARS CoV-2 pneumonia and its correlation with other clinical and laboratory markers needs to be evaluated., Methods: We assessed 39 patients [age: 64 y(60.1-68.7)] with confirmed SARS CoV-2 pneumonia. A total of 24 patients were hospitalized until the follow-up test, 9 were discharged early and 6 required a transfer to critical care unit. Two ultrasound scans of the lung were performed on day 1 and 4 of patients' hospitalization. Primary endpoint was the magnitude of association between a global lung ultrasound score (LUS) and clinical and laboratory markers. Secondary endpoint was the association between the evolution of LUS with the corresponded changes in clinical and laboratory outcomes during hospitalization period., Results: LUS score on admission was higher among the deteriorating patients and significantly (P=0.038-0.0001) correlated (Spearman's rho) with the levels of C-reactive protein (0.58), lymphocytes (-0.33), SpO 2 (-0.48) and oxygen supplementation (0.48) upon admission. The increase in LUS score between the two scans was significantly correlated (0.544, P=0.006) with longer hospital stay., Conclusion: Lung ultrasound assessment can be a useful as an imaging modality for SARS CoV-2 patients. Larger studies are needed to further investigate the predictive role of LUS in the duration and the outcome of the hospitalization of these patients., (Copyright © 2021 SPLF and Elsevier Masson SAS. All rights reserved.)

Obstructive sleep apnea (OSA) patients would strongly benefit from comfortable home diagnosis, during which detection of wakefulness is essential. Therefore, capacitively-coupled electrocardiogram (ccECG) and bioimpedance (ccBioZ) sensors were used to record the sleep of suspected OSA patients, in parallel with polysomnography (PSG). The three objectives were quality assessment of the unobtrusive signals during sleep, prediction of sleep-wake using ccECG and ccBioZ, and detection of high-risk OSA patients. First, signal quality indicators (SQIs) determined the data coverage of ccECG and ccBioZ. Then, a multimodal convolutional neural network (CNN) for sleep-wake prediction was tested on these preprocessed ccECG and ccBioZ data. Finally, two indices derived from this prediction detected patients at risk. The data included 187 PSG recordings of suspected OSA patients, 36 (dataset "Test") of which were recorded simultaneously with PSG, ccECG, and ccBioZ. As a result, two improvements were made compared to prior studies. First, the ccBioZ signal coverage increased significantly due to adaptation of the acquisition system. Secondly, the utility of the sleep-wake classifier increased as it became a unimodal network only requiring respiratory input. This was achieved by using data augmentation during training. Sleep-wake prediction on "Test" using PSG respiration resulted in a Cohen's kappa (κ) of 0.39 and using ccBioZ in κ = 0.23. The OSA risk model identified severe OSA patients with a κ of 0.61 for PSG respiration and κ of 0.39 using ccBioZ (accuracy of 80.6% and 69.4%, respectively). This study is one of the first to perform sleep-wake staging on capacitively-coupled respiratory signals in suspected OSA patients and to detect high risk OSA patients based on ccBioZ. The technology and the proposed framework could be applied in multi-night follow-up of OSA patients.

Transfer entropy (TE) has been used to identify and quantify interactions between physiological systems. Different methods exist to estimate TE, but there is no consensus about which one performs best in specific applications. In this study, five methods (linear, k-nearest neighbors, fixed-binning with ranking, kernel density estimation and adaptive partitioning) were compared. The comparison was made on three simulation models (linear, nonlinear and linear + nonlinear dynamics). From the simulations, it was found that the best method to quantify the different interactions was adaptive partitioning. This method was then applied on data from a polysomnography study, specifically on the ECG and the respiratory signals (nasal airflow and respiratory effort around the thorax). The hypothesis that the linear and nonlinear components of cardio-respiratory interactions during light and deep sleep change with the sleep stage, was tested. Significant differences, after performing surrogate analysis, indicate an increased TE during deep sleep. However, these differences were found to be dependent on the type of respiratory signal and sampling frequency. These results highlight the importance of selecting the appropriate signals, estimation method and surrogate analysis for the study of linear and nonlinear cardio-respiratory interactions.

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

Competing Interests: Disclosure: There is no conflict of interest or other disclosures.

Objectives: Sleep time information is essential for monitoring of obstructive sleep apnea (OSA), as the severity assessment depends on the number of breathing disturbances per hour of sleep. However, clinical procedures for sleep monitoring rely on numerous uncomfortable sensors, which could affect sleeping patterns. Therefore, an automated method to identify sleep intervals from unobtrusive data is required. However, most unobtrusive sensors suffer from data loss and sensitivity to movement artifacts. Thus, current sleep detection methods are inadequate, as these require long intervals of good quality. Moreover, sleep monitoring of OSA patients is often less reliable due to heart rate disturbances, movement and sleep fragmentation. The primary aim was to develop a sleep-wake classifier for sleep time estimation of suspected OSA patients, based on single short-term segments of their cardiac and respiratory signals. The secondary aim was to define metrics to detect OSA patients directly from their predicted sleep-wake pattern and prioritize them for clinical diagnosis. Methods: This study used a dataset of 183 suspected OSA patients, of which 36 test subjects. First, a convolutional neural network was designed for sleep-wake classification based on healthier patients (AHI < 10). It employed single 30 s epochs of electrocardiograms and respiratory inductance plethysmograms. Sleep information and Total Sleep Time (TST) was derived for all patients using the short-term segments. Next, OSA patients were detected based on the average confidence of sleep predictions and the percentage of sleep-wake transitions in the predicted sleep architecture. Results: Sleep-wake classification on healthy, mild and moderate patients resulted in moderate κ scores of 0.51, 0.49, and 0.48, respectively. However, TST estimates decreased in accuracy with increasing AHI. Nevertheless, severe patients were detected with a sensitivity of 78% and specificity of 89%, and prioritized for clinical diagnosis. As such, their inaccurate TST estimate becomes irrelevant. Excluding detected OSA patients resulted in an overall estimated TST with a mean bias error of 21.9 (± 55.7) min and Pearson correlation of 0.74 to the reference. Conclusion: The presented framework offered a realistic tool for unobtrusive sleep monitoring of suspected OSA patients. Moreover, it enabled fast prioritization of severe patients for clinical diagnosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Huysmans, Borzée, Buyse, Testelmans, Van Huffel and Varon.)

In this work, a detection and classification method for sleep apnea and hypopnea, using photopletysmography (PPG) and peripheral oxygen saturation (SpO 2 ) signals, is proposed. The detector consists of two parts: one that detects reductions in amplitude fluctuation of PPG (DAP)and one that detects oxygen desaturations. To further differentiate among sleep disordered breathing events (SDBE), the pulse rate variability (PRV) was extracted from the PPG signal, and then used to extract features that enhance the sympatho-vagal arousals during apneas and hypopneas. A classification was performed to discriminate between central and obstructive events, apneas and hypopneas. The algorithms were tested on 96 overnight signals recorded at the UZ Leuven hospital, annotated by clinical experts, and from patients without any kind of co-morbidity. An accuracy of 75.1% for the detection of apneas and hypopneas, in one-minute segments,was reached. The classification of the detected events showed 92.6% accuracy in separating central from obstructive apnea, 83.7% for central apnea and central hypopnea and 82.7% for obstructive apnea and obstructive hypopnea. The low implementation cost showed a potential for the proposed method of being used as screening device, in ambulatory scenarios.

Objective: The performance of a novel unobtrusive system based on capacitively-coupled electrocardiography (ccECG) combined with different respiratory measurements is evaluated for the detection of sleep apnea., Approach: A sleep apnea detection algorithm is proposed, which can be applied to electrocardiography (ECG) and ccECG, combined with different unobtrusive respiratory measurements, including ECG derived respiration (EDR), respiratory effort measured using the thoracic belt (TB) and capacitively-coupled bioimpedance (ccBioz). Several ECG, respiratory and cardiorespiratory features were defined, of which the most relevant ones were identified using a random forest based backwards wrapper. Using this relevant feature set, a least-squares support vector machine classifier was trained to decide if a one minute segment is apneic or not, based on the annotated polysomnography (PSG) data of 218 patients suspected of having sleep apnea. The obtained classifier was then tested on the PSG and capacitively-coupled data of 28 different patients., Main Results: On the PSG data, an AUC of 76.3% was obtained when the ECG was combined with the EDR. Replacing the EDR with the TB led to an AUC of 80.0%. Using the ccECG and ccBioz or the ccECG and TB resulted in similar performances as on the PSG data, while using the ccECG and ccECG-based EDR resulted in a drop in AUC to 67.4%., Significance: This is the first study which tests an apnea detection algorithm on capacitively-coupled ECG and bioimpedance signals and shows promising results on the capacitively-coupled data set. However, it was shown that the EDR could not be accurately estimated from the ccECG signals. Further research into the effect that respiration has on the ccECG is needed to propose alternative EDR estimates.

Clinical activities regarding sleep disordered breathing (SDB) have been sharply interrupted during the initial phase of the coronavirus disease 2019 (COVID-19) epidemic throughout Europe. In the past months, activities have gradually restarted, according to epidemiological phase of COVID-19 and national recommendations. The recent increase in cases throughout Europe demands a reconsideration of management strategies of SDB accordingly. Diagnosis of SDB and initiation of treatment pose some specific problems to be addressed to preserve the safety of patients and health personnel. This perspective document by a group of European sleep experts aims to summarise some different approaches followed in Europe and United States, which reflect national recommendations according to the epidemiological phase of the COVID-19 infection. Respiratory sleep medicine is likely to change in the near future, and use of telemedicine will grow to avoid unnecessary risks and continue to provide optimal care to patients. In addition, the document covers paediatric sleep studies and indications for titration of noninvasive ventilation, as well as precautions to be followed by patients who are already on positive airway pressure treatment. A single consensus document developed by the European Respiratory Society and national societies would be desirable to harmonise SDB management throughout Europe., Competing Interests: Conflict of interest: S. Schiza has nothing to disclose. Conflict of interest: A. Simonds has nothing to disclose. Conflict of interest: W. Randerath has nothing to disclose. Conflict of interest: F. Fanfulla has nothing to disclose. Conflict of interest: D. Testelmans has nothing to disclose. Conflict of interest: L. Grote has nothing to disclose. Conflict of interest: J.M. Montserrat has nothing to disclose. Conflict of interest: J-L. Pepin has nothing to disclose. Conflict of interest: J. Verbraecken has nothing to disclose. Conflict of interest: R. Ersu has nothing to disclose. Conflict of interest: M.R. Bonsignore has nothing to disclose., (Copyright ©ERS 2021.)

Becker muscular dystrophy (BMD) is a rare hereditary neuromuscular disease, caused by a genetic defect in the Duchenne Muscular Dystrophy (DMD) gene. We studied the natural history of respiratory function and its affecting factors in 23 adult BMD patients. These important data are needed for (future) clinical trials in BMD but are largely lacking. Patients had a median age of 51 years (28-78y) and median follow-up duration of 14 years (2-25y). We analysed 190 pulmonary function measurements with a median interval of one year (1-17y) and measured a 1.00% decline of Forced Vital Capacity percent predicted (FVC%pred) per year (p = 0.004). Loss of ambulation significantly increased the annual rate of FVC decline and was dependent of patient's body mass index (BMI; p = 0.015), with increases in BMI correlating with an even more rapid deterioration of FVC. A decline in Medical Research Council (MRC) sum score was significantly correlated with a decline in FVC (p = 0.003). We conclude that adult BMD patients experience a significant but mild respiratory decline. However, this decline is significantly more rapid and clinically relevant after loss of ambulation, which warrants a more vigilant follow-up of respiratory function in this subgroup., Competing Interests: Declaration of Competing Interest KGC is Chairholder of the Emil von Behring Chair for Neuromuscular and Neurodegenerative Disorders by CSL Behring. KGC and several authors of this publication are member of the European Reference Network for Rare Neuromuscular Diseases (ERN EURO-NMD) and of the European Reference Network for Rare Neurological Diseases (ERN-RND). The authors have no competing interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

How the innate and adaptive host immune system miscommunicate to worsen COVID-19 immunopathology has not been fully elucidated. Here, we perform single-cell deep-immune profiling of bronchoalveolar lavage (BAL) samples from 5 patients with mild and 26 with critical COVID-19 in comparison to BALs from non-COVID-19 pneumonia and normal lung. We use pseudotime inference to build T-cell and monocyte-to-macrophage trajectories and model gene expression changes along them. In mild COVID-19, CD8 + resident-memory (T RM ) and CD4 + T-helper-17 (T H17 ) cells undergo active (presumably antigen-driven) expansion towards the end of the trajectory, and are characterized by good effector functions, while in critical COVID-19 they remain more naïve. Vice versa, CD4 + T-cells with T-helper-1 characteristics (T H1 -like) and CD8 + T-cells expressing exhaustion markers (T EX -like) are enriched halfway their trajectories in mild COVID-19, where they also exhibit good effector functions, while in critical COVID-19 they show evidence of inflammation-associated stress at the end of their trajectories. Monocyte-to-macrophage trajectories show that chronic hyperinflammatory monocytes are enriched in critical COVID-19, while alveolar macrophages, otherwise characterized by anti-inflammatory and antigen-presenting characteristics, are depleted. In critical COVID-19, monocytes contribute to an ATP-purinergic signaling-inflammasome footprint that could enable COVID-19 associated fibrosis and worsen disease-severity. Finally, viral RNA-tracking reveals infected lung epithelial cells, and a significant proportion of neutrophils and macrophages that are involved in viral clearance.

Respiratory sinus arrhythmia (RSA) is a form of cardiorespiratory coupling. It is observed as changes in the heart rate in synchrony with the respiration. RSA has been hypothesized to be due to a combination of linear and nonlinear effects. The quantification of the latter, in turn, has been suggested as a biomarker to improve the assessment of several conditions and diseases. In this study, a framework to quantify RSA using support vector machines is presented. The methods are based on multivariate autoregressive models, in which the present samples of the heart rate variability are predicted as combinations of past samples of the respiration. The selection and tuning of a kernel in these models allows to solve the regression problem taking into account only the linear components, or both the linear and the nonlinear ones. The methods are tested in simulated data as well as in a dataset of polysomnographic studies taken from 110 obstructive sleep apnea patients. In the simulation, the methods were able to capture the nonlinear components when a weak cardiorespiratory coupling occurs. When the coupling increases, the nonlinear part of the coupling is not detected and the interaction is found to be of linear nature. The trends observed in the application in real data show that, in the studied dataset, the proposed methods captured a more prominent linear interaction than the nonlinear one., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Morales, Borzée, Testelmans, Buyse, Van Huffel and Varon.)

The electrocardiogram (ECG) is an important diagnostic tool for identifying cardiac problems. Nowadays, new ways to record ECG signals outside of the hospital are being investigated. A promising technique is capacitively coupled ECG (ccECG), which allows ECG signals to be recorded through insulating materials. However, as the ECG is no longer recorded in a controlled environment, this inevitably implies the presence of more artefacts. Artefact detection algorithms are used to detect and remove these. Typically, the training of a new algorithm requires a lot of ground truth data, which is costly to obtain. As many labelled contact ECG datasets exist, we could avoid the use of labelling new ccECG signals by making use of previous knowledge. Transfer learning can be used for this purpose. Here, we applied transfer learning to optimise the performance of an artefact detection model, trained on contact ECG, towards ccECG. We used ECG recordings from three different datasets, recorded with three recording devices. We showed that the accuracy of a contact-ECG classifier improved between 5 and 8% by means of transfer learning when tested on a ccECG dataset. Furthermore, we showed that only 20 segments of the ccECG dataset are sufficient to significantly increase the accuracy.