Thomas Penzel

Charité Universitätsmedizin Berlin | Charité · Interdisciplinary Center of Sleep Medicine

Objectives The emergence of sleep disturbances in response to major stressful events has been previously documented. Heart rate variability (HRV) is an objective marker that provides insight into autonomic nervous system dynamics. The aim of the present study was to examine the preliminary effectiveness of a one-shot session of cognitive behavioral...

Introduction The lack of a definitive measurement of excessive daytime sleepiness (EDS) represents a key challenge in studying this important symptom. The most common approach in research and clinical practice is to utilize the Epworth Sleepiness Scale (ESS), a brief questionnaire measuring the tendency to doze off in eight common situations [1]. H...

The polysomnogram (PSG) is the gold standard for evaluating sleep quality and disorders. Attempts to automate this process have been hampered by the complexity of the PSG signals and heterogeneity among subjects and recording hardwares. Most of the existing methods for automatic sleep stage scoring rely on hand-engineered features that require prio...

Introduction: Sleep is increasingly recognized as a major risk factor for neurodegenerative disorders such as Alzheimer's disease (AD). Methods: Using an magnetic resonance imaging (MRI)-based AD score based on clinical data from the Alzheimer's Disease Neuroimaging Initiative 1 (ADNI1) case-control cohort, we investigated the associations betwe...

Automatic sleep stage classification is vital for evaluating the quality of sleep. Conventionally, sleep is monitored using multiple physiological sensors that are uncomfortable for long-term monitoring and require expert intervention. In this study, we propose an automatic technique for multi-stage sleep classification using photoplethysmographic...

Zusammenfassung Leistungssportlerinnen und Leistungssportler sind hohen physischen und psychischen Anforderungen ausgesetzt, um optimale Ergebnisse zu erzielen. Dafür ist auch die Funktion der Regenerationsphase wichtig, zu der maßgeblich ein erholsamer Schlaf beiträgt. Es gibt jedoch Hinweise, dass bei Leistungssportlerinnen und Leistungssportlern...

Recent investigations show that many people affected by SARS‐CoV2 (COVID‐19) report persistent symptoms 2–3 months from the onset of the infection. Here, we report the Italian findings from the second International COVID‐19 Sleep Study survey, aiming to investigate sleep and dream alterations in participants with post‐acute symptoms, and identify t...

Purpose Despite polysomnography being the gold standard method of diagnosing obstructive sleep apnea (OSA), it is time-consuming and has long waiting lists. Alternative methods including questionnaires and portable sleep devices have been developed to increase the speed of diagnosis. However, most questionnaires such as the STOP-BANG questionnaire...

Cardiopulmonary coupling (CPC) is a technique that generates sleep spectrogram by calculating the cross-spectral power and coherence of heart rate variability and respiratory tidal volume fluctuations. There are several forms of CPC in the sleep spectrogram, which may provide information about normal sleep physiology and pathological sleep states....

The novel coronavirus disease-2019 (COVID-19) and the ensuing pandemic have greatly impacted the global healthcare system due to its high infectiousness, associated high mortality, and a complete lack of immunity in the population. Globally, the COVID-19 pandemic has unleashed a health crisis that has not only seriously disrupted people's lives but...

Here we discuss the current perspectives of comprehensive heart rate variability (HRV) analysis in electrocardiogram (ECG) signals as a non-invasive and reliable measure to assess autonomic function in sleep-related breathing disorders (SDB). It is a tool of increasing interest as different facets of HRV can be implemented to screen and diagnose SD...

Many people report suffering from post‐acute sequelae of COVID‐19 or “long‐COVID”, but there are still open questions on what actually constitutes long‐COVID and how prevalent it is. The current definition of post‐acute sequelae of COVID‐19 is based on voting using the Delphi‐method by the WHO post‐COVID‐19 working group. It emphasizes long‐lasting...

Die Basis evidenzbasierter Diagnostik in der Medizin soll durch sogenannte Health Technology Assessment (HTA)-Berichte gesichert werden. Für die Diagnostik der Schlafapnoe wurden ein HTA-Bericht in Deutschland und ein weiterer in den USA erarbeitet. Das diagnostische Vorgehen in der Schlafmedizin ist im klinischen Algorithmus Nicht erholsamer Schla...

Objectives The emergence of sleep disturbances in response to major stressful events has been documented previously. Insomnia and Heart rate variability (HRV) is an objective marker that provides insight into autonomic nervous system dynamics. The aim of the present study was to examine the preliminary efficacy and effectiveness of a one-shot sessi...

Cardiorespiratory interactions are important, both for understanding the fundamental processes of functioning of the human body and for development of methods for diagnostics of various pathologies. The properties of cardiorespiratory interaction are determined by the processes of autonomic control of blood circulation, which are modulated by the h...

For over 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...

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by frequent cessation of breathing during sleep, which cannot be easily diagnosed at the early stage due to the complexity and labor intensity of the polysomnography (PSG). Using a ECG device for OSA detection provides a convenient solution in the current Internet of Things scen...

Some details of cardiovascular and cardio-respiratory regulation and their changes during different sleep stages remain still unknown. In this paper we compared the fluctuations of heart rate, pulse rate, respiration frequency, and pulse transit times as well as EEG alpha-band power on time scales from 6 to 200 s during different sleep stages in or...

Objective Central sleep apnea (CSA) is associated with increased morbidity and mortality in patients with heart failure (HF). We aimed to explore the effectiveness of phrenic nerve stimulation (PNS) on CSA in patients with HF. Methods This was a prospective and non-randomized study. The stimulation lead was inserted into the right brachiocephalic...

Objective: A novel ring-worn oximeter (Circul) uses reflective photoplethysmography and automated signal processing to calculate oxygen desaturations. We evaluated the ability of Circul to detect obstructive sleep apnea in Chinese adults. Methods: We recruited 207 Chinese Han subjects: 70% males, mean age 48.2±14.7 years, mean BMI 27.6±4.8 kg/m2...

Purpose: The COVID-19 pandemic affects mental health and sleep, resulting in frequent nightmares. Therefore, identifying factors associated with nightmare frequency is important, as it can indicate mental health issues. The study aimed to investigate increases in nightmare frequency comparing the pre-pandemic and pandemic period, and identify its...

Sleep quality has a significant impact on human physical and mental health. The detection of sleep-wake states is thus of significant importance in the study of sleep. The performance of classical machine learning models for automated sleep detection depends on the signals considered and feature extraction methods. Moreover, hand-crafted features a...

Background: Obstructive sleep apnoea (OSA) causes, among other things, intermittent blood oxygen desaturations, increasing the sympathetic tone. Yet the effect of desaturations on heart rate variability (HRV), a simple and noninvasive method for assessing sympathovagal balance, has not been comprehensively studied. We aimed to study whether desatu...

Objectives Sleep disorders can arise from work. Employees who experience work overload are more likely to develop sleep problems. Poor sleep leads to decreased performance, sick leave, and accidents. Therefore, sleep disorders may be linked to workplace hazards as well as decreased occupational health, however, the relationship remains unknown. Me...

[This corrects the article DOI: 10.1007/s11818-022-00347-7.].

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...

The European Somnologist certification programme was developed by the European Sleep Research Society to improve patient care in sleep medicine by providing an independent evaluation of theoretical and practical knowledge. The examination of eligible experts plays a key role in this procedure. A process was started more than 15 years ago to create...

Abstract Purpose: Obstructive sleep apnea (OSA) may increase the risk of severe COVID-19; however, the level of potential modulation has not yet been established. The objective of the study was to determine the association between high risk of OSA, comorbidities, and increased risk for COVID-19, hospitalization, and intensive care unit (ICU) treatm...

Context: The use of daytime napping as a countermeasure in sleep disturbances has been recommended but its physiological evaluation at high altitude is limited. Objective: To evaluate the neuroendocrine response to hypoxic stress during a daytime nap and its cognitive impact. Design, Subject, and Setting: Randomized, single-blind, three period cros...

Objective This study aimed to evaluate the effect of sacubitril-valsartan (SV) on central apneas (CA) and obstructive apneas (OA) in patients with heart failure with reduced ejection fraction (HFrEF). Methods In patients with HFrEF, SV initiation was titrated to the highest tolerable dosage. Patients were evaluated with portable apnea monitoring,...

Purpose Socioeconomic factors are known to modulate health. Concerning sleep apnea, influences of income, education, work, and living in a partnership are established. However, results differ between national and ethnic groups. Results also differ between various clinical studies and population-based approaches. The goal of our study was to determi...

There has been increasing concern about the long‐term impact of coronavirus disease 2019 (COVID‐19) as evidenced by anecdotal case reports of acute‐onset parkinsonism and the polysomnographic feature of increased rapid eye movement sleep electromyographic activity. This study aimed to determine the prevalence and correlates of dream‐enactment behav...

Background: The WatchPAT (WP) device was shown to be accurate for the diagnosis of sleep apnea and is widely used worldwide as an ambulatory diagnostic tool. While it records peripheral arterial tone (PAT) and not electrocardiogram (ECG), the ability of it to detect arrhythmias is unknown and was not studied previously. Common arrhythmias such as...

The European Sleep Research Society (ESRS) has a strong focus on sleep research in Europe. In addition, the ESRS supports sleep medicine in Europe by providing a platform of exchange and communication for the national sleep societies of all European countries and by providing committees that support co‐ordination for important clinical activities....

Background There are studies about polysomnographic (PSG) characteristics of patients with either Obesity Hypoventilation Syndrome (OHS) or addiction. We aimed to investigate the PSG characteristics of OHS patients with opium addiction (OA) and those on methadone maintenance treatment (MMT) for treatment of addiction. Methods In this cross-sectiona...

Purpose Diagnosis and treatment of obstructive sleep apnea are traditionally performed in sleep laboratories with polysomnography (PSG) and are associated with significant waiting times for patients and high cost. We investigated if initiation of auto-titrating CPAP (APAP) treatment at home in patients with obstructive sleep apnea (OSA) and subsequ...

Sleep apnea is traditionally classified as obstructive sleep apnea (OSA), which occurs when the upper airway collapses due to the relaxation of oropharyngeal musculature, and central sleep apnea occurs when the brainstem cannot stimulate breathing. Most sleep apnea in patients with heart failure (HF) results from coexisting OSA and central sleep ap...

Introduction: A growing number of studies have demonstrated that the coronavirus disease-19 (COVID-19) pandemic has severely affected sleep and dream activity in healthy people. To date, no investigation has examined dream activity specifically in COVID-19 patients. Methods: As part of the International COVID-19 Sleep Study (ICOSS), we compared...

The increasing availability and complexity of sleep and circadian data are equally exciting and challenging. The field is in constant technological development, generating better high-resolution physiological and molecular data than ever before. Yet, the promise of large-scale studies leveraging millions of patients is limited by suboptimal approac...

The influence of higher nervous activity on the processes of autonomic control of the cardiovascular system and baroreflex regulation is of considerable interest, both for understanding the fundamental laws of the functioning of the human body and for developing methods for diagnostics and treatment of pathologies. The complexity of the analyzed sy...

This chapter reviews the common health data security and privacy challenges to provide an overview of the context—the concerns and the types of cybersecurity threats that healthcare institutions face. Also highlighted are the latest scientific work related to two primary solutions for protecting health data used for individual care, namely, access...

Recognition of sleep and wake states is one of the relevant parts of sleep analysis. Performing this measurement in a contactless way increases comfort for the users. We present an approach evaluating only movement and respiratory signals to achieve recognition, which can be measured non-obtrusively. The algorithm is based on multinomial logistic r...

Oscillometry or Forced Oscillation Technique, traditionally used in intermittent clinical measurements, has recently gained substantial attention from its application as a continuous monitoring tool for large and small airways. However, low frequency (< 8 Hz) continuous oscillometry faces high breathing noise, and hence requires high oscillation am...

This protocol paper describes the second survey produced by the International Covid Sleep Study (ICOSS) group with the aim to examine the associations between SARS-CoV-2 infection and sleep, sleepiness, and circadian problems as potential predisposing factors for more severe COVID-19 disease profile and for development of Long-COVID in the general...

Sleep health and tracking sleep with contemporary wearables have become more popular. Sleep disorders, in particular, sleep-disordered breathing, have a higher prevalence than estimated previously. Many patients with apnea and hypopnea events suffer whereas others do not report complaints or show cardiovascular consequences. Assessment with wearabl...

Objectives Sleep is important for human health and well-being. No previous study has assessed whether the COVID-19 pandemic impacts sleep and daytime function across the globe. Methods This large-scale international survey used a harmonised questionnaire. Fourteen countries participated during the period of May–August 2020. Sleep and daytime probl...

Sleep is increasingly recognised as a major risk‐factor for cognitive ageing and neurodegenerative disorders such as late‐onset Alzheimer’s Disease (LOAD). Poor sleep quality has been linked to impaired cerebral clearance of amyloid‐beta, neurofibrillary tangles and reduced cognitive function. Recent studies have also highlighted a relationship bet...

The deposition of amyloid-β (Aβ) in the brain is a risk factor for Alzheimer’s disease (AD). Therefore, new strategies for the stimulation of Aβ clearance from the brain can be useful in preventing AD. Transcranial photostimulation (PS) is considered a promising method for AD therapy. In our previous studies, we clearly demonstrated the PS-mediated...

Purpose: An early prescreening in suspected obstructive sleep apnea (OSA) patients is desirable to expedite diagnosis and treatment. However, the accuracy and applicability of current prescreening tools is insufficient. We developed and tested an unbiased scoring system based solely on objective variables, which focuses on the diagnosis of severe...

PAT Technology is a plethysmographic based measurement method which facilitates the accurate recording of the pulsatile volume changes of the arteries of peripheral vascular beds at the distal end of the fingers over sustained periods of time. It represents a departure from previously available plethysmographic methods, in so far as it applies a un...

Obstructive sleep apnea (OSA) is a sleep disorder in which repetitive upper airway obstructive events occur during sleep. These events can induce hypoxia, which is a risk factor for multiple cardiovascular and cerebrovascular diseases. Chronic obstructive pulmonary disease (COPD) is a disorder which induces a persistent inflammation of the lungs. T...

Purpose of the work is to identify the directional coupling between the structures of the brain and the autonomic control of the heart rate variability, to analyze the changes in these coupling in sleep and in wakefulness. Infra-slow oscillations of the electroencephalograms potential and low-frequency components (0.04-0.15 Hz) of the interbeat int...

Sleep staging is of paramount importance in children with suspicion of pediatric obstructive sleep apnea (OSA). Complexity, cost, and intrusiveness of overnight polysomnography (PSG), the gold standard, have led to the search for alternative tests. In this sense, the photoplethysmography signal (PPG) carries useful information about the autonomous...

This paper presents a generic method to enhance performance and incorporate temporal information for cardiorespiratory-based sleep stage classification with a limited feature set and limited data. The classification algorithm relies on random forests and a feature set extracted from long-time home monitoring for sleep analysis. Employing temporal f...

Importance: Underlying pathomechanisms of brain white matter hyperintensities (WMHs), commonly observed in older individuals and significantly associated with Alzheimer disease and brain aging, have not yet been fully elucidated. One potential contributing factor to WMH burden is chronic obstructive sleep apnea (OSA), a disorder highly prevalent i...

Guidelines for the evaluation and management of sleep disorders from national societies provide recommendations that may be regionally appropriate but may not always be practical or relevant in other parts of the world. A task force of experts from the World Sleep Society's (WSS) International Sleep Medicine Guidelines Committee and Sleep and Breat...

Background Prediction tools without patient-reported symptoms could facilitate widespread identification of obstructive sleep apnea (OSA). Research Question What is the diagnostic performance of machine-learning derived OSA prediction tools using readily available data without patient responses to questionnaires, and how do they compare to the STO...

A new approach for detection oscillatory patterns and estimation of their dynamics based by a modified CWT skeleton method is presented. The method opens up additional perspectives for the analysis of subtle changes in the oscillatory activity of complex nonstationary signals. The method was applied to analyze unique experimental signals obtained i...

Various novelties have emerged since the last update of the position paper on sleep medicine in cardiology of the German Cardiac Society in 2014, which is why this revision became necessary. This new version not only includes all new studies available up to the date of printing, including references, updates on pathophysiology, diagnostics, and tre...

Sleep-related breathing disorders are very common in cardiovascular disease patients with, for example, difficult-to-control arterial hypertension, coronary artery disease, valvular heart disease, cardiac arrhythmias, or heart failure, and are associated with a worse prognosis. The therapy of sleep-related breathing disorders can usefully complemen...

New trends in sleep medicine make use of the increased computational power of digital transformation. A current trend toward fewer sensors on the body of the sleeper and to more data processing from derived signals is observed. Telemedicine technologies are used for data transmission and for better patient management in terms of diagnosis and in te...

Objective: Many have reported odd dreams during the pandemic. Given that dreams are associated with mental health, understanding these changes could provide crucial information about wellbeing during the pandemic. This study explored associations between COVID-19 and dream recall frequency (DRF), and related social, health, and mental health facto...

Background: The changing responsibilities of pharmacists contribute to a lack of qualified pharmacists to fill vacant positions, particularly in rural areas. Consequently, pharmacy managers cover various duties, including an increasing number of nights being on duty that can impair daytime concentration and performance. The objective of the study...

Objective: Nocturnal recordings of heart rate and respiratory rate usually require several separate sensors or electrodes attached to different body parts -- a disadvantage for at-home screening tests and for large cohort studies. In this paper, we demonstrate that a state-of-the-art accelerometer placed at subjects' wrists can be used to derive r...