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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

Les effets d’un effort cognitif prolongé chez des athlètes ayant subi une commotion cérébrale

Caron, Gabriel 05 1900 (has links)
La fatigue est l’un des symptômes les plus fréquents et persistants chez les victimes de commotion cérébrale. Au cours des dernières années, des signes d’altérations cognitives post-commotionnelles à la suite d’un effort aérobie, soit une forme de fatigue dont la cause est physique plus que cognitive, ont été trouvés à court et à long terme chez des athlètes étudiants. Or, puisque ces athlètes évoluent dans un contexte où ils doivent non seulement performer dans leur discipline sportive, mais aussi à l’école ou au travail, il convient de se demander si un effort mental soutenu n’aurait pas le même effet chez cette population. L’objectif de cette étude était donc de déterminer si des athlètes étudiants ayant subi une commotion cérébrale (groupe HC) se sentent plus fatigués ou ont davantage tendance à se fatiguer mentalement que ceux n’ayant jamais subi de commotion cérébrale (groupe ST). Les sujets devaient répondre à une série de questionnaires auto-rapportés. Ils devaient aussi compléter une tâche informatisée recrutant les fonctions exécutives avant et après avoir répondu à une épreuve de raisonnement, d’une durée d’une heure, visant à simuler un examen scolaire. Leur réaction physiologique à la tâche était mesurée via un appareil d’électroencéphalographie et un cardiofréquencemètre. Si dans l’ensemble les résultats n’appuient pas l’hypothèse initiale, les deux groupes ont montré des différences notables dans leur façon de répondre à la tâche. Nous avons notamment constaté l’absence d’un effet de pratique à la condition la plus facile ainsi qu’une variabilité de la performance généralement plus élevée chez les sujets avec un historique de commotion cérébrale. De plus, contrairement au groupe témoin, ceux qui rapportaient des symptômes plus importants de fatigue cognitive quotidienne, de somnolence et de dépression montraient également une moins bonne précision à la tâche après un effort cognitif soutenu. Ces résultats suggèrent que les commotions cérébrales pourraient avoir pour effet d’accroître la sensibilité de certains individus à l’effort cognitif. De futures études devraient se pencher sur cette relation afin de la confirmer et d’en comprendre les causes. / Fatigue is one of the most common and persistent symptoms in concussion victims. In recent years, signs of post-concussive cognitive impairment following aerobic exertion, a form of fatigue whose cause is more physical than cognitive, have been found in both shortand long-term in student athletes. However, since these athletes evolve in a context where they must not only perform in their sport, but also at school or at work, it is worth asking whether sustained mental effort would have the same effect in this population. The objective of this study was therefore to determine whether student athletes who have suffered a concussion (HC group) feel more tired or are more likely to become mentally fatigued than those who have never suffered a concussion (ST group). Subjects were asked to complete a series of self-report questionnaires. They were also required to complete a computerized task recruiting executive functions before and after completing a one-hour reasoning test meant to simulate a school examination. Their physiological response to the task was measured using electroencephalography and a heart rate monitor. While the results do not support the original hypothesis, the groups showed significant differences in the way they responded to the task. Particularly, we found the absence of a practice effect at the easiest condition as well as a generally higher performance variability in subjects with a history of concussion. In addition, unlike the control group, those who reported greater symptoms of daily cognitive fatigue, drowsiness and depression also showed poorer task accuracy after sustained cognitive effort. These results suggest that concussions may have the effect of increasing the sensitivity of some individuals to cognitive effort. Future studies should investigate this relationship in order to confirm it and understand its causes.
352

Analyse de la variabilité de la fréquence cardiaque chez les femmes enceintes atteintes d'apnée obstructive du sommeil

Laramée, Mathieu 03 1900 (has links)
Objectif: Les troubles respiratoires du sommeil (TRS) sont courants pendant la grossesse et sont associés à des conséquences néfastes pour la santé de la mère et du fœtus. Ceux-ci peuvent être causés par des changements dans l'équilibre sympathovagal (ESV), qui peuvent être estimés par des analyses de la variabilité de la fréquence cardiaque (VFC). Le but de l'étude est d'évaluer la VFC chez les femmes enceintes souffrant d'apnée obstructive du sommeil (AOS) à l’aide d’enregistrements polysomnographiques (PSG) à trois moments. Matériel et méthode: Dix-sept femmes enceintes diagnostiquées avec une AOS légère à modérée ont effectué des PSGs: au 2e trimestre (PSG1), au 3e trimestre, traitées avec une orthèse d’avancement mandibulaire (OAM) titrée (PSG2) et 3-6 mois post-partum (PSG3). Les données ont été analysées par conditions en intervalles cumulés de 5 minutes d’état de base (Baseline) et en intervalles cumulés de 3 minutes avant le début des événements d'AOS (Event) pour chaque stade du sommeil (NREM2, NREM3, REM) au cours de la nuit. Résultats: Le ESV (rapport de puissance spectrale basses fréquences / hautes fréquences) était statistiquement significatif pour toutes les PSGs cumulatifs par conditions (stades de sommeil Baseline p <0,01 et stades de sommeil Event p <0,01; REM> NREM2> NREM3). Une diminution significative de l'indice d'apnée-hypopnée (IAH) a été observée à PSG2 (PSG1 vs PSG2; p < 0,01). À l'analyse post hoc, à PSG2 uniquement, l'activité parasympathique (puissance spectrale des hautes fréquences normalisées (% HF normalisé)) en condition Event diminue significativement dans les stades de sommeil NREM2 (p = 0,01) et NREM3 (p <0,01) par rapport au % HF normalisé en condition Baseline pour les mêmes stades de sommeil. Conclusions: Bien que l’IAH soit réduit avec le traitement de l’OAM pendant la grossesse, l’influence du système nerveux autonome sur les évènements respiratoires semble modérée. / Purpose: Sleep breathing disorders are common during pregnancy and are associated with adverse consequences for the health of the mother and the fetus. These can be caused by changes in sympatho-vagal balance (SVB), which can be estimated through heart rate variability (HRV) analyses. The aim of the study is to assess the HRV in pregnant women with obstructive sleep apnea (OSA) at three time points. Methods: Seventeen pregnant women diagnosed with mild to moderate OSA performed 3 polysomnographic recordings (PSG): in the second trimester (PSG1), in the third trimester treated with a titrated oral appliance (OA) (PSG2) and 3-6 months post-partum. Data were analyzed in cumulative 5 minutes baseline interval samples (Baseline) and in cumulative 3 minutes interval samples before the onset of the OSA events (Event) for each sleep stages (NREM2, NREM3, REM) over the course of the night. Results: SVB (Low-/High-Frequency power ratio) was statistically significant for all cumulative PSGs per samples (Baseline sleep stages p < 0.01 and Event sleep stages p < 0.01 ; REM > NREM2 > NREM3). Significant diminution of apnea-hypopnea index (AHI) was observed at PSG2 (PSG1 vs PSG2; p < 0,01). In post hoc analysis, at PSG2 only, Event parasympathetic activity (Normalized High-Frequency % (Normalized HF %)) decreases significantly in NREM2 (p = 0.01) and NREM3 (p < 0.01) when compared to respective Baseline Normalized HF %. Conclusions: Results suggest normal shifts in SVB across sleep stages. Although AHI is reduced with the treatment of OA during pregnancy, the influence of the autonomic nervous system on respiratory events seems to remain mild.
353

Methods for assessment of autonomic nervous system activity from cardiorespiratory signals

Tiinanen, S. (Suvi) 20 August 2019 (has links)
Abstract A cardiorespiratory system is highly regulated via the autonomic nervous system (ANS), whose function can be quantified noninvasively by analyzing electrocardiogram (ECG), blood pressure (BP) and respiration signals. Several conditions and illnesses are linked with imbalance of the ANS. This thesis aimed to develop methods for describing the ANS regulation of a cardiovascular system from short-term cardiorespiratory measurements. More specifically, the role of breathing rate and its effects on traditional frequency domain based cardiovascular indexes describing ANS control is addressed. The main contributions are as follows: 1) an adaptive filtering based method to remove respiratory influences from cardiovascular signals and indexes was developed. The adaptive filter reduced the bias caused by low respiration rate, enabling the usage of spontaneous respiration measurement protocol over controlled respiration. 2) Methods to quantify respiratory sinus arrhythmia (RSA) index from cardiovascular signals were developed as well: two methods utilizes adaptive filtering and either the measured respiration signal or the ECG-derived respiration signal and one method uses independent component analysis. Developed RSA index methods allow varying respiration rates making them physiologically more accurate than traditional high frequency power with fixed respiration rate, often used as RSA index. 3) Tools for studying the power and the frequency of low frequency (LF) oscillations of cardiovascular signals were developed, including a time-frequency representation for analyzing varying data. An experimental study was conducted with patients of continuum of cardiovascular risks. According to results, aging decreased the frequency of LF oscillation, whereas coronary artery disease decreased it further. 4) Two new ECG-derived respiration (EDR) methods utilizing decomposition techniques were developed. The proposed methods yielded statistically significant improvements over previously developed EDR methods. EDR method enables to get respiratory information from ECG, which in its turn reduces needed modalities in ANS quantification. This thesis provides methods to quantify indexes describing the ANS function more accurately by acknowledging the respiration effects. The results of this thesis may be utilized in various application areas, ranging from clinical to physiology research up to commercial health, wellness and sport products. / Tiivistelmä Autonominen hermosto säätelee tarkasti sydän- ja verenkiertoelimistöä sekä hengitystä. Autonomisen hermoston toimintaa voidaan analysoida laskennallisin menetelmin noninvasiivisesti mitatuista elektrokardiogrammi- (EKG, sydänsähkökäyrä), verenpaine- ja hengityssignaaleista. Useita tekijöitä ja sairauksia voidaan yhdistää autonomisen hermoston epätasapainoon. Väitöskirjassa kehitettiin menetelmiä sydän- ja verisuonijärjestelmän autonomisen säätelyn kuvaamiseksi lyhytaikaisista kardiorespiratorisista tallenteista. Erityistä huomiota on kiinnitetty hengityksen vaikutukseen perinteisiin taajuustasosta laskettaviin muuttujiin, jotka kuvaavat autonomisen hermoston toimintaa. Väitöskirjan päätuloksia ja -tuotoksia ovat: 1) uusi adaptiiviseen suodatukseen pohjautuva laskennallinen menetelmä hengitysvaikutuksien poistamiseksi sydän- ja verisuonisignaaleista. Adaptiivinen suodatin vähensi matalan hengitystaajuuden aiheuttamaa vääristymää hermoston toimintaa kuvaavista parametreistä. Uusi menetelmä mahdollistaa kontrolloimattoman eli vapaan hengitystaajuus-protokollan käytön autonomisen hermoston toiminnan mittauksissa. 2) Uusia menetelmiä respiratorisen sinus arrytmian (RSA) määrittämiseksi sydän- ja verisuonisignaaleista. Kehitetyissä menetelmistä kahdessa käytetään adaptiivista suodatusta hyödyntäen joko mitattua hengityssignaalia tai EKG:stä johdettua hengityssignaalia. Kolmas menetelmä pohjautuu itsenäisten komponenttien analyysiin. Kehitetyt menetelmät RSA:n laskemiseksi sallivat hengitystaajuuden vaihtelun mittauksien aikana, mikä tekee ne fysiologisesti tarkemmaksi kuin perinteisesti käytetty korkeataajuinen (HF) komponentti, joka lasketaan taajuustasossa tietyltä kaistalta riippumatta hengitystaajuudesta. 3) Kehitettiin ja sovellettiin menetelmiä EKG:n ja verenpaineen matalataajuisten (LF) heilahtelujen tutkimista varten. Yhdessä tutkimuksessa sovellettiin aika-taajuustason esitystapaa vaihtelevan datan analysoimiksi. Kokeellinen tutkimus tehtiin aineistolla, joka oli jatkumo sydän- ja verisuonitautien riskejä omaavista potilaista jo sairastuneisiin potilaisiin. Ikääntyminen pienensi matalataajuisen heilahtelun taajuutta ja sepelvaltimosairaus pienensi sitä edelleen. 4) Kaksi uutta hajotelmatekniikoita hyödyntävää menetelmää, joilla lasketaan EKG:stä hengitysvirtausignaali-estimaatti (EDR). Kehitettyjen EDR-menetelmien suorituskyky osoittautui tilastollisesti paremmaksi kuin aikaisemmat menetelmät. Koska hengityssignaali ja -taajuus voidaan johtaa suoraan EKG:stä, tarvittavien mittaussensoreiden määrää vähenee. Lisäksi EDR:ää voidaan hyödyttää autonomisen hermoston toimintaa kuvaavien parametrien estimoinnissa. Väitöskirja tarjoaa menetelmiä autonomisen hermoston toiminnan mittaamiseksi huomioiden erityisesti hengityksen vaikutus estimoitaviin parametreihin. Väitöskirjan tuloksia voidaan soveltaa useissa kardiorespiratorisia signaaleja hyödyntävissä sovelluksissa aina kliinisestä työstä fysiologian tutkimukseen ja kaupallisiin hyvinvointi-, terveys- ja urheilusovelluksiin. / Huomautus/Notice Painetussa virheellinen ISBN: 978-952-62-2312-4, oikea 978-952-62-2310-0. Printed version has incorrect ISBN: 978-952-62-2312-4, it should be 978-952-62-2310-0.
354

Wearing the Inside Out: The Effects of Exogenous Oxytocin, Reading, and Stress on the Expression of Empathy for Victims of Trauma

Seddio, Kaylee Rae 12 1900 (has links)
Considerable psycho-physiological research on empathy examines biological structures such as the hypothalamic-pituitary-adrenal axis (HPA-axis) and oxytocin systems as efficacious methods for strengthening positive emotional responses. This study recruited 76 adult participants (54 female, 23 male) for the purpose of evaluating the effects oxytocin and fiction reading have on empathetic responses. Participants completed a measure of trauma and received either intranasal oxytocin, a story created to induce emotional responses, or a neutral non-fiction story. Stressors were counterbalanced as a family or non-family stimuli to assess changes in stress response measured by salivary cortisol and heart rate variability. Results supported existing research stating that heart rate variability (HRV) is a more sensitive measure of stress. HRV statistically significantly interacted between type of stressor and PTSD symptomology (1, 70) = 5.018, p = .028, η2 =0.06. Scores on the Interpersonal Reactivity Index (IRI) indicated there were increases in empathy across time, but were not impacted by exposure to stress or treatment condition. Trauma was identified as a statistically significant factor on heart rate variability F(1, 70) = 8.39, p = .005, η2 = .10. Treatment condition did not impact cortisol levels across time F(2, 71) = .2.532, p = .087, η2 = .11. Taken together, these results suggest support for the use of biomarkers in measuring the rate of stress and recovery for those with and without trauma. These findings suggest potential avenues for translational research and implications for theory and practice.
355

Cardiac Vagal Tone & Attentional Control Settings in Adaptive Choice

Speller, Lassiter Freeman, M.A. 05 October 2021 (has links)
No description available.
356

Nové metody pro analýzu spánku a klasifikaci / Novel methods for sleep analysis and classification

Navrátilová, Markéta January 2020 (has links)
Tato diplomová práce se zabývá metodami pro analýzu a klasifikaci spánku. Popisuje jakjednotlivé spánkové fáze a vzorce biosignálů v průběhu spánku, tak metody pro klasifi-kaci. Příznaky jsou extrahovány na dodaných biosignálech ECG, EDA a RIP. Na základětěchto příznaků jsou klasifikovány jednotlivé spánkové fáze s využitím klasifikátoru ná-hodný les. Parametry klasifikátoru jsou optimalizovány a následně jsou vyhodnocenydosažené výsledky. Pomocí metod pro redukci dimenzionality je soubor příznaků analy-zován a výsledky jsou porovnány s výsledky ze standardní klasifikace. Řešení pro vizuali-zaci jak samotných nezpracovaných signálů, tak extrahovaných příznaků je navrhnuto aimplementováno. Dosažené výsledky jsou porovnány s publikovanými metodami.
357

Software pro ruční rozměření signálů EKG / Software for manual delineation of ECG signals

Jež, Radek January 2011 (has links)
This thesis deals with evaluation EKG in terms of classification rhythm and analysis HRV. In theoretic part of work are described basics of heart physiology and its usual pathology, basics of electrocardiography, evaluation EKG and standard methods of HRV evaluation. In practical part are described algorithms used in created application. Mainly describes technique of rhythm evaluation, ectopic rhythms and delineation error elimination, data preparing for HRV evaluation, drift removal from DES and HRV evaluation methods. Created program was tested on CSE and MIT- BIH database records. For lack of suitable data and absence of tested data, it wasn’t possible to test all the classification rules of used algorithms. Tested part of program appears reliable and functional.
358

Mobilní systém pro monitorování sportovní aktivity / Mobil system for monitoring of sports activity

Maleňák, Filip January 2015 (has links)
The aim of this master’s thesis is to analyse methods that are used for monitoring athlete’s activities and a description of current technical solutions with a focus on heart rate and respiratory rate monitoring. The presented solution shows the possibilities of using available open source SW and HW technologies and their implementation in the design of an integrated tool for monitoring sports activities with the iOS operating system.
359

Pilotstudie zur Evaluierung fetaler Herzratenvariabilitätsparameter bei frühem vorzeitigem Blasensprung mittels abdominaler fetaler Elektrokardiographie

Schmieder, Claudia 14 April 2015 (has links)
Die nicht-invasive Analyse der fetalen Herzratenvariabilität mittels abdominaler Elektrokardiographie stellt eine neue Methode zur Beurteilung des fetalen Zustandes dar. Die Herzratenvariabilität gilt hier als ein sensitives Maß der autonomen Regulation. Bereits mit Beginn der zweiten Schwangerschaftshälfte ist es möglich, über das mütterliche Abdomen ein fetales Elektrokardiogramm abzuleiten und einer Herzratenvariabilitätsanalyse zuzuführen. Das Untersuchungskollektiv dieser Arbeit umfasste Frauen mit frühem vorzeitigem Blasensprung als Modell einer pathologischen Alteration des fetalen Zustandes sowie Frauen mit normalen Schwangerschaften zwischen der 20. und 28. Schwangerschaftswoche. Die technische Umsetzung und Analyse der fetalen Herzratenvariabilität erfolgte in Kooperation mit dem Institut für Biomedizinische Technik der TU Dresden. Insgesamt wurden 25 Datensätze der Auswertung zugeführt. Eine Reifung des autonomen Nervensystems des Feten mit ansteigendem Gestationsalter konnte mittels der Herzratenvariabilitätsanalyse gezeigt werden. Zur Risikostratifizierung der Feten bei frühem vorzeitigem Blasensprung konnten bei der Betrachtung der Herzratenvariabilitätsparameter keine signifikanten Unterschiede zum Normalkollektiv erhoben werden. Die Analyse der Parameter erfolgte hierbei unabhängig von den fetalen Verhaltenszuständen. Es konnte gezeigt werden, dass die nicht-invasive Analyse der Herzratenvariabilitätsanalyse methodisch und technisch in der Lage ist, den Fetalzustand und dessen Alterationen zu erfassen.
360

Ambulatory monitoring of electrodermal and cardiac functioning in anxiety and worry

Doberenz, Sigrun 11 October 2011 (has links)
Emotions are an integral part of the human experience and their interpretation can provide valuable but also misleading clues about oneself and other people’s state of mind. Negative emotional states can be perceived as uncomfortable and – when experienced chronically – can develop into anxiety and mood disorders. The more pervasive these disorders the more severely they affect and disable a person’s everyday functioning and often their sleep as well. According to Lang and colleagues (1998), emotions may be expressed verbally, behaviorally, and physiologically, i.e., emotions can be reported, observed, and objectively measured. Each measurement approach provides important, unique, and often conflicting information that can be used in the assessment and treatment evaluation of psychological disorders affecting the emotions. Autonomic measures have been used to indicate the physiological components of emotions, such as those along the worry-anxiety-fear-panic spectrum. Worry has been shown to suppress cardiac responses to imaginal feared material (see Borkovec, Alcaine, & Behar, 2004) and reduce autonomic variability (Hoehn-Saric, McLeod, Funderburk, & Kowalski, 2004; Hoehn-Saric, McLeod, & Zimmerli, 1989). Results for panic and anticipatory anxiety are less conclusive but theoretically these states should go along with increased autonomic arousal. Abnormal autonomic arousal might also be present during sleep as both panic disorder and worrying have been associated with sleeping difficulties. However, most empirical research has been confined to the laboratory where high internal validity is achieved at the cost of poor ecological validity. Thus, the purpose of this doctoral dissertation is to extend and validate laboratory findings on worry, anticipatory anxiety, and panic using ambulatory monitoring. Twenty-four hour monitoring not only can give valuable insights into a person’s daytime emotional experience but also allows observing how these emotions might affect their sleep in their natural environment. In the following chapter, the reader will be introduced to a conceptual framework that ties together worry, anxiety, fear, and panic, and related anxiety disorders (section 2.1), to autonomic arousal and electrodermal and cardiac arousal in particular (section 2.2), to sleep and its relation to autonomic arousal and anxiety disorders (section 2.3), and to ambulatory monitoring (section 2.4). After illustrating the aims of this thesis (chapter 3), chapters 4 to 6 present the results of three empirical studies conducted as part of this doctoral research. The first study deals solely with electrodermal monitoring and how it is affected by confounding variables in an ambulatory context (chapter 4). The next study then seeks to investigate the relationship between electrodermal arousal and anticipatory anxiety and panic in a sample of panic disorder patients and healthy controls. The last study focuses primarily on the effect of trait and state worry on subjective and objective sleep and electrodermal and cardiac arousal in a group of high and low worriers. Chapters 7 to 9 summarize and integrate the findings from these three empirical studies, discuss methodological limitations, and provide an outlook into future research.

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