Heart rate variability in normal and pathological sleep

Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS), whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non-linear heart rate variability (HRV) analyses. the application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM) stage is characterized by a likely sympathetic predominance associated with a vagal withdrawal, while the opposite trend is observed during non-REM sleep. More recently, the use of non-linear tools, such as entropy-derived indices, have provided new insight on the cardiac autonomic regulation, revealing for instance changes in the cardiovascular complexity during REM sleep, supporting the hypothesis of a reduced capability of the cardiovascular system to deal with stress challenges. Interestingly, different HRV tools have been applied to characterize autonomic cardiac control in different pathological conditions, from neurological sleep disorders to sleep disordered breathing (SDB). in summary, linear and non-linear analysis of HRV are reliable approaches to assess changes of autonomic cardiac modulation during sleep both in health and diseases. the use of these tools could provide important information of clinical and prognostic relevance.European Regional Development Fund-Project FNUSA-ICRCUniv Milan, L Sacco Hosp, Dept Biomed & Clin Sci L Sacco, Div Med & Pathophysiol, I-20157 Milan, ItalyOsped Niguarda Ca Granda, Ctr Epilepsy Surg C Munari, Ctr Sleep Med, Dept Neurosci, Milan, ItalyUniversidade Federal de São Paulo, Inst Sci & Technol, Dept Sci & Technol, São Paulo, BrazilUniv Fdn Cardiol, Inst Cardiol Rio Grande do Sul, Porto Alegre, RS, BrazilFdn S Maugeri, Sleep Med Unit, Veruno, ItalySt Annes Univ Hosp, Int Clin Res Ctr, Brno, Czech RepublicUniversidade Federal de São Paulo, Inst Sci & Technol, Dept Sci & Technol, São Paulo, BrazilEuropean Regional Development Fund-Project FNUSA-ICRC: CZ.1.05/1.1.00/02.0123Web of Scienc

Effects of circadian rhythm phase alteration on physiological and psychological variables: Implications to pilot performance (including a partially annotated bibliography)

The effects of environmental synchronizers upon circadian rhythmic stability in man and the deleterious alterations in performance and which result from changes in this stability are points of interest in a review of selected literature published between 1972 and 1980. A total of 2,084 references relevant to pilot performance and circadian phase alteration are cited and arranged in the following categories: (1) human performance, with focus on the effects of sleep loss or disturbance and fatigue; (2) phase shift in which ground based light/dark alteration and transmeridian flight studies are discussed; (3) shiftwork; (4)internal desynchronization which includes the effect of evironmental factors on rhythmic stability, and of rhythm disturbances on sleep and psychopathology; (5) chronotherapy, the application of methods to ameliorate desynchronization symptomatology; and (6) biorythm theory, in which the birthdate based biorythm method for predicting aircraft accident susceptability is critically analyzed. Annotations are provided for most citations

A Review of Approaches for Sleep Quality Analysis

Sleep quality is directly related to overall wellness and can reveal symptoms of several diseases. However, the term ‘‘sleep quality’’ still lacks a definitional consensus and is commonly assessed in sleep labs with polysomnography, comprising high costs, or through sleep questionnaires, a highly subjective technique. Multiple methods have been proposed to address the estimation of sleep quality, and devices were developed to conduct the examination in the subject’s home. The objective of this paper is to analyze the methods and the devices presented in the literature, assessing the development of objective markers that could lead to an improvement of the subjective sleep experience understanding, leading to developments in the treatment of sleep quality deficits. A systematic review was conducted, selecting research articles published from 2000 to 2018, and two research questions were formulated, specifically, ‘‘what methods for sleep quality assessment have been developed’’ and ‘‘what kind of measures are employed by the devices that have been developed to estimate sleep quality.’’ The research trend for the assessment of sleep quality is based on the sleep macrostructure, and it was verified that despite the convenience and considerable popularity among the consumers of home health monitoring of devices, such as actigraphs, the validity of these tools regarding the estimation of sleep quality still needs to be systematically examined. A detailed resume of the key findings and the identified challenges are presented, ascertaining the main gaps in the current state of the art.info:eu-repo/semantics/publishedVersio

Automatic sleep staging based on classifícation methods

Dissertação de Mestrado em Engenharia Biomédica apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraDuring the sleep the brain generates different types of waves depending on the brain stage. To characterise these brain states, the two structures exist: the macrostructure and microstructure. The macrostructure is composed by five sleep stages (designated by N3, N2, N1, REM, W) whose classification is based on the present wave types. The microstructure is characterised by transitional states and the Cyclic Alternating Pattern (CAP) is an example of it. CAP is a periodic cerebral activity prevalent during NREM sleep-stage and composed by A-phases (A1, A2 or A3) and B-phases. The visual scoring of macro- and microstructure are important elements for the diagnosis and prognosis of some diseases. Although this task of both is a time consuming process, which demands automatic scoring. This thesis proposes different classifications methods (discriminate classifiers, kNN and SVM) to detect automatically the sleep stages and A-phases. The classifiers are validated with a dataset that comprise 30 patients. For sleep stages the better model is SVM which obtained an accuracy off 72%, the sensitivities for the each sleep stage are 62%, 54%, 73%, 83% and 69% for W, N1, N2, N3 and REM stages. Regarding the CAP staging the best classifier method is also SVM with an accuracy of 71%, the sensitivities are 76%, 58%, 44% and 24% for B, A1, A2 and A3, respectively. The prediction of A-phases with the SVM yield the best results to date.Durante o sono o c´erebro gera diferentes tipos de ondas, dependo do estado em que se encontra. Para caracterizar estes estados cerebrais existem duas estruturas: a macroestrutura e microestrutura. A macroestrutura ´e composta por cinco diferentes estados de sono (designados por N3, N2, N1, REM, W), cuja classifica¸c˜ao ´e baseada de acordo com o tipo de onda gerado. A microestrutura ´e caracterizada por estados transicionais, sendo um exemplo o Padr˜ao C´ıclico Alternante (CAP). O CAP ´e uma actividade cerebral peri´odica prevalente durando o estado de sono NREM e composto por fases A (A1, A2 e A3) e fases B. O estadiamento visual da macro e microestrutura s˜ao importante para o diagn´ostico e progn´ostico de algumas doen¸cas. Contudo, esta tarefa ´e um processo bastante demorado para ambas as estruturas, o que gera uma necessidade de um estadiamento autom´atico. Esta tese prop˜oes diferentes m´etodos de classifica¸c˜ao (classificadores discriminantes, k-NN e SVM) para detectar automaticamente os diferentes estados de sono e as fases A. Estes classificadores s˜ao validados com uma amostra composta por 30 pacientes. Para os estados de sono o melhor modelo ´e o SVM que obt´em uma taxa de sucesso de 72% e de sensibilidades para cada estado de sono W, N1, N2, N3 e REM de 62%, 54%, 73%, 83% e 69%, respectivamente. Quanto ao estadiamento do CAP o melhor m´etodo de classifica¸c˜ao ´e tamb´em o SVM com uma taxa de sucesso de 71% e sensibilidades de 76%, 58%, 44% e 24% para as fases B, A1, A2 e A3. As sensibilidades obtidas por este ´ultimo m´etodo s˜ao muito acima das encontradas na literatura at´e `a data

Big data analysis of cyclic alternating pattern during sleep using deep learning

Sleep scoring has been of great interest since the invention of the polysomnography method, which enabled the recording of physiological signals overnight. With the surge in wearable devices in recent years, the topic of what is high-quality sleep, how can it be determined and how can it be achieved attracted increasing interest. In the last two decades, cyclic alternating pattern (CAP) was introduced as a scoring alternative to traditional sleep staging. CAP is known as a synonym for sleep microstructure and describes sleep instability. Manual CAP scoring performed by sleep experts is a very exhausting and time-consuming task. Hence, an automatic method would facilitate the processing of sleep data and provide a valuable tool to enhance the understanding of the role of CAP. This thesis aims to expand the knowledge about CAP by developing a high-performance automated CAP scoring system that can reliably detect and classify CAP events in sleep recordings. The automated system is equipped with state-of-the-art signal processing methods and exploits the dynamic, temporal information in brain activity using deep learning. The automated scoring system is validated using large community-based cohort studies and comparing the output to verified values in the literature. Our findings present novel clinical results on the relationship between CAP and age, gender, subjective sleep quality, and sleep disorders demonstrating that automated CAP analysis of large population based studies can lead to new findings on CAP and its subcomponents. Next, we study the relationship between CAP and behavioural, cognitive, and quality-of-life measures and the effect of adenotonsillectomy on CAP in children with obstructive sleep apnoea as the link between CAP and cognitive functioning in children is largely unknown. Finally, we investigate cortical-cardiovascular interactions during CAP to gain novel insights into the causal relationships between cortical and cardiovascular activity that are underpinning the microstructure of sleep. In summary, the research outcomes in this thesis outline the importance of a fully automated end-to-end CAP scoring solution for future studies on sleep microstructure. Furthermore, we present novel critical information for a better understanding of CAP and obtain first evidence on physiological network dynamics between the central nervous system and the cardiovascular system during CAP.Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 202

Advances in Clinical Neurophysiology

Including some of the newest advances in the field of neurophysiology, this book can be considered as one of the treasures that interested scientists would like to collect. It discusses many disciplines of clinical neurophysiology that are, currently, crucial in the practice as they explain methods and findings of techniques that help to improve diagnosis and to ensure better treatment. While trying to rely on evidence-based facts, this book presents some new ideas to be applied and tested in the clinical practice. Advances in Clinical Neurophysiology is important not only for the neurophysiologists but also for clinicians interested or working in wide range of specialties such as neurology, neurosurgery, intensive care units, pediatrics and so on. Generally, this book is written and designed to all those involved in, interpreting or requesting neurophysiologic tests

Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 141)

This special bibliography lists 267 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1975

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 349)

This bibliography lists 149 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during April, 1991. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance