De nombreux événements cardiovasculaires se déroulent au cours du sommeil(13).Divers auteurs ont étudié la variabilité du rythme cardiaque durant les différentes phases du sommeil chez le sujet sain (2) ou souffrant de diverses pathologies (3,5). Seules quelques publications décrivent le lien entre le sommeil et la variabilité du rythme cardiaque (4). L’interaction entre la variabilité du rythme cardiaque et les spectres de puissance du signal EEG de sommeil peut être étudiée par une analyse de cohérence (12). Cette méthode donne les fonctions de cohérence, de gain et de décalage de phases entre deux signaux à une fréquence déterminée. Les signaux principaux utilisés pour cette analyse de cohérence sont la bande de puissance de haute fréquence (HF) de la variabilité de l’intervalle RR, reflet de l’activité cardiaque vagale (14), et la bande de puissance de fréquence delta du signal EEG, associée au sommeil lent profond (1), à la fréquence du maximum de cross-spectrum entre ces bandes de puissances. Dans le but de mieux comprendre cette interaction, diverses questions se posent : • Existe-t-il, chez l’homme jeune en bonne santé, une interaction entre les spectres de puissance de l’intervalle RR et du signal EEG ? • Quelle bande de fréquence des puissances du signal EEG est la plus liée à la bande de puissance de haute fréquence de la variabilité de l’intervalle RR au cours du sommeil ? • Quel est l’impact du vieillissement sur ce lien ? • Existe-t-il une altération complète (cohérence, gain, décalage de phase) de l’interaction entre la bande de puissance de HF de l’intervalle RR et la bande de puissance de fréquence delta de sommeil chez l’individu souffrant d’un syndrome d’apnées-hypopnées de sommeil (SAHS) modéré ou sévère ? • Y a-t-il une diminution des valeurs de la cohérence et une modification du décalage de phase entre les signaux de puissance des bandes de HF du signal ECG et de la fréquence delta de l’EEG au cours du sommeil de la personne souffrant d’insomnie chronique primaire? • Les valeurs du gain pourraient-elles être les seules à être altérées chez le patient souffrant d’un trouble dépressif majeur (TDM)? Pour répondre à ces questions, plusieurs groupes ont été constitués : 8 adultes jeunes (18-23 ans)(11), 19 hommes d’âge moyen (36-54 ans) vs. 16 adultes jeunes (16-28 ans)(10), 12 patients souffrant d’un SAHS sévère vs. 12 patients souffrant d’un SAHS modéré à sévère vs. 12 hommes contrôles (9), 14 hommes souffrant d’insomnie chronique primaire vs. 12 adultes contrôles (8), 10 hommes souffrant de TDM vs. 10 hommes contrôles(7). Aucun patient ne présente une autre pathologie que celle décrite et tous ont été sevrés d’éventuelles médications psychotropes. De ces analyses, il apparaît que, chez l’homme jeune en bonne santé, de toutes les bandes de puissance du signal EEG de sommeil, les modifications de la bande de puissance delta est la plus liée aux modifications de la bande de puissance de haute fréquence de la variabilité du rythme cardiaque (11); et que le lien entre les modifications observées entre les bandes de puissance delta et HF est stable malgré l’effet du vieillissement observé dans l’architecture du sommeil et le contrôle de l’activité cardiaque (10). Les patients souffrant de SAHS présentent une perte du contrôle du lien entre le sommeil et la variabilité du rythme cardiaque, avant même l’apparition des symptômes cliniques cardiaques (9). Les personnes souffrant d’insomnie chronique primaire montrent une diminution de la force, voire une instabilité, du lien dynamique entre l’activité cérébrale de sommeil et la variabilité du rythme cardiaque(8). Les patients souffrant de trouble dépressif majeur démontrent une diminution de l’efficacité du lien entre les structures impliquées dans le contrôle du sommeil et les centres cardiovasculaires, mais pas de la force de ce lien (7), comme suggéré par les observations d’une neuroplasticité altérée chez les personnes dépressives (6). L’étude de la relation entre l’activité cérébrale et la variabilité du rythme cardiaque au cours du sommeil pourrait donc permettre une meilleure compréhension des processus neuro-cérébraux impliqués dans le développement des maladies cardiovasculaires mais également des pathologies de sommeil et des maladies psychiatriques. Elle pourrait peut-être, à l’aide d’une technique simple comprenant des enregistrements ECG et EEG au cours du sommeil, anticiper l’apparition de maladies graves cardiovasculaires, bien avant les premiers signes de la pathologie et permettre ainsi l’application de mesures préventives plutôt que curatives. Références. 1. Aeschbach D, Borbély AA. All-night dynamics of the human sleep EEG. J Sleep Res 1993; 2:70-81. 2. Bonnet MH, Arand DL. Heart rate variability: sleep stage, time of night, and arousal influences. Electroencephalogr Clin Neurophysiol 1997; 102(5):390-396. 3. Bonnet MH, Arand DL. Heart rate variability in insomniacs and matched normal sleepers. Psychosom Med. 1998 Sep-Oct;60(5):610-5. 4. Brandenberger G, Viola AU, Ehrhart J, Charloux A, Geny B, Piquard F, Simon C. Age-related changes in cardiac autonomic control during sleep. J Sleep Res. 2003; 12(3):173-80. 5. Dingli K, Assimakopoulos T, Wraith PK, Fietze I, Witt C, Douglas NJ. Spectral oscillations of RR intervals in sleep apnoea/hypopnoea syndrome patients. Eur Respir J. 2003; 22: 943-50. 6. Fossati P, Radtchenko A, Boyer P. Neuroplasticity: from MRI to depressive symptoms. Eur Neuropsychopharmacol. 2004; 14 Suppl 5:S503-10. 7. Jurysta F, Kempenaers C; Lancini J; Lanquart JP; van de Borne P; Linkowski P. Altered interaction between cardiac vagal influence and delta sleep EEG suggests an altered neuroplasticity in patients suffering from major depressive disorder. Acta Psych Scand (in press) 8. Jurysta F, Lanquart J, Sputaels V, Dumont M, Migeotte PF, Leistedt S, Linkowski P, van de Borne P. The Impact of Chronic Primary Insomnia on the Heart Rate - EEG Variability Link. Clin. Neurophysiol. 2009; 120(6):1054-60. 9. Jurysta F, Lanquart JP, van de Borne P, Migeotte PF, Dumont M, Degaute JP, Linkowski P. The link between cardiac autonomic activity and sleep delta power is altered in men with sleep apnea-hypopnea syndrome. Am J Physiol Regul Integr Comp Physiol. 2006; 291(4):R1165-71. 10. Jurysta F, van de Borne P, Lanquart JP, Migeotte PF, Degaute JP, Dumont M, Linkowski P. Progressive aging does not alter the interaction between autonomic cardiac activity and delta EEG power. Clin Neurophysiol. 2005; 116(4):871-7. 11. Jurysta F, van de Borne P, Migeotte PF, Dumont M, Lanquart JP, Degaute JP, Linkowski P. A study of the dynamic interactions between sleep EEG and heart rate variability in healthy young men. Clin. Neurophysiol. 2003; 114(11):2146-55. 12. Koopmans LH. The Spectral Analysis of Time Series. Academic Press. New York and London, 1974. 13. Lavery CE, Mittleman MA, Cohen MC, Muller JE, Verrier RL. Nonuniform nighttime distribution of acute cardiac events: a possible effect of sleep states. Circulation. 1997; 96(10):3321-7. 14. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Heart rate variability. Standards of measurement, physiological interpretation, and clinical use. Eur Heart J 1996; 17: 354-381.

Cardiovascular risk in primary hyperparathyroidism (HPT) is controversial, and studies mainly from Europe associate HPT with increased cardiovascular morbidity and mortality. Cardiovascular morphology and function were evaluated prospectively in 31 consecutive HPT patients (mean serum calcium 2.97±0.04) and randomly enrolled controls matched for age and sex. Patients were re-examined at normocalcemia about one year after parathyroidectomy. HPT patients showed an operatively reversible disturbance in endothelial vasodilatory function that seemed unrelated to an early sign of atherosclerosis, i.e. thickness of carotid artery intima-media complex. Acute hypercalcemia in healthy subjects induced a similar impairment in endothelial function, which suggests a dependence on biochemical rather than structural vascular changes in HPT. Echocardiography showed left ventricular diastolic dysfunction and supernormal systolic performance being reversed after operation. Left ventricular mass tended to be irreversibly increased. During exercise HPT patients exhibited greater rise in systolic blood pressure compared to controls and an increased number of premature ventricular beats. This indicated increased work load and a propensity for fatal cardiac events. Following surgery, an improvement with less pronounced ST-segment depression was seen. 24-hour ambulatory blood pressure monitoring showed irreversibly increased levels despite maintained diurnal rhythm, while 24-hour heart rate variability analysis displayed blunted nocturnal increase of low and very low frequency bands that was corrected postoperatively. Parathyroidectomy seems to alleviate most of the cardiovascular disturbances in HPT, except for hypertension. This is consistent with the normalised longevity in HPT treated with parathyroidectomy and supports active treatment of HPT.

The effects of in-vehicle automation and driving assistant systems on the mental workload and situation awareness of drivers have been the interest of many studies; some of the implications of automation in such man-machine systems have been identified. Due to the introduction of advanced automated systems in agricultural machinery, farmers are currently working with semi-autonomous vehicles. A human factors perspective on the design of these systems will ensure safe and efficient operation of such man-machine systems. In this study, a systematic approach was utilized to address human factors issues associated with operating a semi-autonomous agricultural vehicle, and to provide design recommendations. The study was carried out in three stages. First, a task analysis was used to identify tasks associated with operating an agricultural vehicle and to select appropriate experimental variables. Next, a preliminary experiment was performed to validate the test procedure and measurement techniques. Finally, the main experiment was administered. Experiments were conducted using the Tractor Driving Simulator located in the Agricultural Ergonomics Laboratory at the University of Manitoba. Thirty young experienced tractor drivers participated in this study. The experiment investigated the effects of i) vehicle steering task automation (VSTA) and ii) implement control and monitoring task automation (ICMTA) on mental workload and situation awareness of drivers. It was found that ICMTA significantly affected situation awareness (and its underlying components) of the operator. The situation awareness of drivers increased as the automation support level increased, but the highest level of automation, where the participants were out of the task loop, resulted in low situation awareness, similar to the condition with no automation support. VSTA only reduced the attentional demand of the situation, one of the three components of the situation awareness, which had negative effect on overall situation awareness. Based on the results from a subjective mental workload measure, moderate levels of mental workload were reported when the participants were involved in the implement control and monitoring task loop. The highest level of ICMTA reduced the average mental workload by 18%. Reaction time of drivers and number of errors committed by drivers both decreased as the automation level increased. / October 2015

Στόχος της παρούσας εργασίας αποτελεί η έγκαιρη πρόβλεψη οξυαιμίας βασιζόμενη στην ανάλυση των πολύ χαμηλής συχνότητας συστατικών του εμβρυϊκού καρδιακού ρυθμού και των καταγραφών της εμβρυϊκής παλμικής οξυμετρίας (FSpO2) κατά τη διάρκεια του τοκετού. Για τη φασματική ανάλυση έγινε εφαρμογή του συνεχούς μετασχηματισμού κυματιδίων (CWT). Για την ανάλυση των καταγραφών του FSpO2 υπολογίστηκε το ποσοστό του συνολικού χρόνου όπου ο FSpO2 είναι κάτω του ορίου 30% (TFSpO2<30%). Όπως αποδείχθηκε τόσο από την εφαρμογή του CWT, όσο και από την παράμετρο TFSpO2<30%, οι κυματισμοί του εμβρυϊκού καρδιακού ρυθμού στην περιοχή συχνοτήτων του 0.01 Hz, παρουσιάζουν ικανοποιητική ευαισθησία (80% and 90%, αντίστοιχα) για την έγκαιρη πρόβλεψη οξυαιμίας, ενώ ο συνδυασμός τους παρουσιάζει υψηλή προσδιοριστικότητα (89%). Τα αποτελέσματα της ανάλυσης των δεδομένων όπως προκύπτουν από την ανάλυση του εμβρυϊκού καρδιακού ρυθμού – μέσω εφαρμογής του CWT – και των καταγραφών της εμβρυϊκής παλμικής οξυμετρίας δύναται να αποτελέσουν μια επιπρόσθετη πηγή πληροφορίας όσον αφορά την κατάσταση του εμβρύου βοηθώντας ταυτοχρόνως τον γυναικολόγο στην απόφαση για το χρόνο και τον τρόπο διεξαγωγής του τοκετού. / The objective of the present study is the prediction of fetal acidemia based on the Very Low Frequency (VLF) components of the Fetal Heart Rate (FHR) and Fetal Pulse Oximetry (FSpO2) recordings during labor. In order to perform the spectral analysis, we applied the Continuous Wavelet Transform (CWT). The evaluation of FSpO2 was based on calculating the time duration in which the FSpO2 was less than 30% (TFSpO2<30%). We demonstrate that the oscillating activity of the FHR of about 0.01 Hz identified by the CWT and the TFSpO2<30% parameter, show an adequate sensitivity (80% and 90%, respectively) in predicting fetal acidemia, whereas the combination of these two variables shows a very good specificity (89%). The results of the analysis of our data demonstrate that the analysis of the fetal heart rate by the CWT and the fetal pulse oximetry recordings may provide additional source of information about fetal status and to alert the clinician to decide under objective conditions when and how to perform the delivery.

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.

Vagal tone, a measure of parasympathetic activity via the vagus nerve, is known to be associated with positive emotion because it promotes social engagement and self-soothing behavior. Heart rate variability (HRV), especially high frequency oscillation, is a direct measure of vagal tone, and has been used in previous studies to test the correlation between vagal tone and positive emotion. This study aims to determine if the two major oscillations of heart rate variability, high frequency (HF-HRV) and low frequency (LF-HRV) can predict pro-social behavior, which is classified as giving donations to charities. Baseline LF- and HF-HRV levels were recorded, and compared to how much each participant donated after watching several donation appeals by charities. Results showed there was no significant difference in either LF- or HF-HRV levels between donors and non-donors. A negative correlation was found between both LF and HF-HRV levels and donation behavior, contradicting research that predicts a positive correlation between the two variables. There was no significant effect of gender on donation amount. This research gives insight in to how physiological changes can affect psychological processes, such as emotional expression.

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that attacks the motor system and contributes to a range of cognitive and behavioral impairments (e.g., behavioral and emotional disinhibition, planning and problem solving difficulties, impulsivity, attention, and personality change). This executive dysfunction may contribute to selfregulatory impairment across several domains, including cognitive skills, thought processes, emotion regulation, interpersonal skills, and physiology, that may be crucial to the quality of life (QOL), or well being, of patients and their caregivers. Given the relentless course and prognosis of ALS, palliative treatments for ALS should target the full range of self-regulatory deficits. Thirty-seven patient-caregiver pairs completed questionnaires regarding the patients’ ability to regulate emotions, social behavior, and thought patterns. Patients also completed neuropsychological measures of executive functions and provided measures of glycosylated hemoglobin (A1c) and heart rate variability (HRV). Results suggest that SR and EF deficits exist on a continuum in ALS, such that some patients evidence adequate or superior ability to self-regulate while others evidence deficits. Patient- caregiver agreement about patients’ selfregulatory capacity across domains was generally weak to moderate. Patients perceived themselves to have less capacity for global regulation than caregivers perceived them to have, patients perceived less dyadic cohesion than caregivers, and patients perceived themselves to ruminate more than caregivers indicated. Overall, caregivers tended to perceive a more pervasive pattern of deficits compared to patients. Additionally, measures of SR and EF were not strongly inter-correlated in general, challenging the idea that SR in different domains depends on a common resource. Accordingly, correlations among measures of theoretically similar constructs (i.e., EF and SR) were small to moderate in magnitude and non-significant. With regard to physiological functioning, when patients had better regulated glucose (A1c), patients and caregivers perceived better global regulation. A similar pattern emerged with patient ratings, with higher baseline HRV linked to less emotional lability. Last, mixed results were obtained when predicting patient and caregiver QOL. Less rumination, less dyadic cohesion and more social anxiety were associated with higher QOL for patients. Caregivers’ QOL was not significantly related to their perceptions of patients’ self-regulatory capacity in any area.

Playing violent video games may provoke aggression. Psycho-physiological methods may provide knowledge about the underlying psychological processes. Most previous studies have been performed in laboratory settings at daytime with adults. Thus the aim of this thesis was to investigate psycho-physiological (autonomic and HPA related reactions), sleep-related and emotional responses in teenage boys to playing a violent and a non-violent video game at home before going to sleep. In Study I the autonomic responses differed between the violent and the non-violent game during playing and more distinctly during sleep. In Study II the HPA axis was not affected by video gaming at all. In Study III, the effect of habits of playing violent games was assessed (≤ 1h/day and ≥ 3h/day). High versus low experience of violent gaming were related to different autonomic, sleep-related and emotional processes at exposure to a violent and a non-violent game, during playing and during sleep. The present thesis demonstrated that violent and non-violent games induce different autonomic responses during playing and – more distinctly – during sleep. Frequent gaming seems to influence physiological, sleep-related and emotional reactions, possibly as an expression of desensitization processes.

Heart rate variability (HRV), the changes in the beat-to-beat heart rate calculated from the electrocardiogram (ECG), is a key indicator of an individual's cardiovascular condition. Assessment of HRV has been shown to aid clinical diagnosis and intervention strategies. However, the variety of HRV estimation methods and contradictory reports in this field indicate that there is a need for a more rigorous investigation of these methods as aids to clinical evaluation. This thesis investigates the development of appropriate HRV signal processing techniques in the context of pilot studies in two fields of potential application, sleep and head-up tilting (HUT). A novel method for characterising normality in the ECG using both timing information and morphological characteristics is presented. A neural network, used to learn the beat-to-beat variations in ECG waveform morphology, is shown to provide a highly sensitive technique for identifying normal beats. Fast Fourier Transform (FFT) based frequency-domain HRV techniques, which require re-sampling of the inherently unevenly sampled heart beat time-series (RR tachogram) to produce an evenly sampled time series, are then explored using a new method for producing an artificial RR tachogram. Re-sampling is shown to produce a significant error in the estimation of an (entirely specified) artificial RR tachogram. The Lomb periodogram, a method which requires no re-sampling and is applicable to the unevenly sampled nature of the signal is investigated. Experiments demonstrate that the Lomb periodogram is superior to the FFT for evaluating HRV measured by the LF/HF-ratio, a ratio of the low to high frequency power in the RR tachogram within a specified band (0.04-0.4 Hz). The effect of adding artificial ectopic beats in the RR tachogram is then considered and it is shown that ectopic beats significantly alter the spectrum and therefore must be removed or replaced. Replacing ectopic beats by phantom beats is compared to the case of ectopic-realted RR interval removal for the FFT and Lomb methods for varying levels of ectopy. The Lomb periodogram is shown to provide a signficantly better estimate of the LF/HF- ratio under these conditions and is a robust method for measuring the LF/HF-ratio in the presence of (a possibly unknown number of) ectpoic beats or artefacts. The Lomb peridogram and FFT-based techniques are applied to a database of sleep apnoeic and normal subjects. A new method of assessing HRV during sleep is proposed to minimise the confounding effects on HRV of changes due to changing mental activity. Estimation of LF/HF-ratio using the Lomb technique is shown to separate these two patient groups more effectively than with FFT-based techniques. Results are also presented for the application of these methods to controlled (HUT) studies on subjects with syncope, an autonomic nervous system problem, which indicate that the techniques developed in this thesis may provide a method for differentiating between sub-classes of syncope.

Base teórica: Na apneia obstrutiva do sono (AOS) ocorrem obstruções totais ou subtotais da faringe, levando a despertares e/ou hipoxemia. Atinge principalmente pessoas acima de 70 anos. Causa despertares que contribuem para sonolência e diminuição da qualidade de vida. Nos despertares, ocorrem mudanças no controle autonômico. Indivíduos com dor possuem uma estimulação simpática constante durante o sono e episódios frequentes de excitação e despertar. Pacientes com dor e apneia apresentam redução da modulação vagal. O presente estudo avalia a atividade do sistema nervoso autonômico por meio de parâmetros cardíacos, sonolência, dimensões de dor com gravidade da apneia obstrutiva do sono em idosos. Métodos: Estudo transversal com indivíduos de ambos os sexos, com idade entre 65 a 80 anos, fisicamente independentes, com e sem dor crônica. A amostra foi dividida em dois grupos de acordo com a gravidade da AOS determinada pelo índice de apneiahipopneia (IAH) obtido por polissonografia portátil (IAH <15 / hora e IAH> 15 / hora). Questionários validados foram empregados para avaliar a dor e sonolência. Para avaliar a modulação simpática, utilizou-se análise espectral, avaliada durante 10 minutos de descanso, seguidos por 10 minutos de estimulação simpática com Stroop Color test. Resultados: Cinquenta e oito indivíduos, com idades entre 71 ± 4 anos, 40% homens, foram incluídos. Não foram observadas diferenças significativas em qualquer escala de dor ou sonolência entre grupos de gravidade da AOS. Os indivíduos com IAH> 15 mostraram atenuada resposta simpática ao estresse em comparação a indivíduos com IAH <15, apenas na presença de presença de dor crônica. Indivíduos com queixa de dor, mas com IAH <15 tiveram uma resposta simpática normal. Conclusão: Idosos com apneia, moderada a grave possuem atenuada reatividade simpática ao estresse mental na presença de dor crônica. / Background: In obstructive sleep apnea (OSA) occurs total or subtotal obstruction of the pharynx, leading to arousals and / or hypoxemia. Mainly affects people over 70 years. Awakenings contributing to cause drowsiness and decreased quality of life. In awakenings, changes occur in the autonomic control. People with pain have a constant sympathetic stimulation during sleep and frequent episodes of excitement and awakening. Patients with pain and apnea have reduced vagal modulation. This study evaluates the activity of the autonomic nervous system, drowsiness, score dimensions with severity of obstructive sleep apnea in the elderly. Methods: This cross-sectional study included individuals of both sexes, aged 65 to 80 years, physically independent, with and without chronic pain. The sample was divided in two groups according to OSA severity determined by the apnea-hypopnea index (AHI) obtained by out-of-center polysomnography (AHI< 15/hour and AHI>15/hour). Validated questionnaires were employed to assess pain and sleepiness. To assess sympathetic modulation, heart rate spectral analysis was evaluated during 10 minutes of rest, followed by 10 minutes of sympathetic stimulation with the Stroop Color Test. Results: Fifty-eight subjects, aged 71±4 years, 40% men, were included. No significant differences were seen in any scale of pain or sleepiness between OSA severity groups. Individuals with AHI>15 showed attenuated sympathetic response to stress compared to individuals with AHI<15, only in the presence of presence of chronic pain. Individuals reporting pain but with AHI<15 had a normal sympathetic response. Conclusion: Elderly subjects with moderate to severe sleep apnea present attenuated sympathetic reactivity to mental stress in the presence of chronic pain.