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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.
91

The correlation between Heart Rate Variability and Apnea-Hypopnea Index is BMI dependent

Wen, Hsiao-Ting 25 July 2012 (has links)
Great progress has been made in sleep medical research in recent years and sleep medicine has thus evolved into a specialized medical field. Sleep apnea syndrome is one of the mostly commonly seen sleep disorders. It is now clear that sleep apnea has adverse effects on the heart and is a risk factor for several cardiovascular diseases. Studies have found that decreased heart rate variability (HRV) is a prognostic factor for cardiovascular disease and it also associated with higher mortality rate. Considering the confounding effect of BMI and sleep apnea severity, this work investigates the correlation between heart rate variability and AHI (apnea-hypopnea index which is used to characterize the severity of sleep apnea) by dividing patients into different BMI subgroups. This work includes 1068 male subjects with complete overnight ECG recordings. The low-frequency (LF), the high-frequency (HF) component and the LF/HF ratio of HRV are computed for the 10 BMI subgroups. The Bootstrap method and the BCa technique for confidence interval estimation are employed to verify the linear association between the HRV measures and the severity of sleep apnea. The experimental results show that statically significant correlation exist between LF/HF ratio and AHI for BMI ¡Ù28 patient groups. Statically significant correlation between LF and AHI also exists for BMI ¡Ù27 patient groups. These results demonstrate that the associations between some of the HRV measures and AHI are clearly BMI dependent.
92

Physiological and Psychological Stress Markers in Concussed Athletes from Injury to Post-return to Play

Senthinathan, Arrani 27 November 2013 (has links)
Introduction: Concussions are a physiologically & psychologically stressful event. Stress markers may provide insight into concussion recovery, but have not been examined. Purpose & Method: To investigate the stress response of concussed athletes compared to controls from injury to post-RTP. Concussed athletes’ Mood states, Perceived Stress, HRV, and Morning & Afternoon Cortisol were assessed at 3 phases of recovery following concussion. Results: Repeated measures ANOVA revealed significant interactions for TMD, Depression, Anger, Confusion, Fatigue, HF norm (rest), LF norm (rest), HF norm (difference between sitting & standing), LF norm (difference between sitting & standing), and LF/HF ratio (difference between sitting & standing). Vigor & Tension demonstrated significant changes over time in the concussed group. Significant difference between the two groups for morning Cortisol levels at phase 3 was revealed. Conclusion: Concussed athletes display elevated levels of stress post-injury. Findings warrant further investigation of stress markers in concussed athletes during recovery.
93

Physiological and Psychological Stress Markers in Concussed Athletes from Injury to Post-return to Play

Senthinathan, Arrani 27 November 2013 (has links)
Introduction: Concussions are a physiologically & psychologically stressful event. Stress markers may provide insight into concussion recovery, but have not been examined. Purpose & Method: To investigate the stress response of concussed athletes compared to controls from injury to post-RTP. Concussed athletes’ Mood states, Perceived Stress, HRV, and Morning & Afternoon Cortisol were assessed at 3 phases of recovery following concussion. Results: Repeated measures ANOVA revealed significant interactions for TMD, Depression, Anger, Confusion, Fatigue, HF norm (rest), LF norm (rest), HF norm (difference between sitting & standing), LF norm (difference between sitting & standing), and LF/HF ratio (difference between sitting & standing). Vigor & Tension demonstrated significant changes over time in the concussed group. Significant difference between the two groups for morning Cortisol levels at phase 3 was revealed. Conclusion: Concussed athletes display elevated levels of stress post-injury. Findings warrant further investigation of stress markers in concussed athletes during recovery.
94

CARDIAC RHYTHM DURING MECHANICAL VENTILATION AND WEANING FROM VENTILATION

Hammash, Muna Hassan 01 January 2010 (has links)
The transition from mechanical ventilation (MV) to spontaneous ventilation during weaning is associated with hemodynamic alterations and autonomic nervous system (ANS) alterations (reflected by heart rate variability [HRV]). Although cardiac dysrhythmias are an important manifestation of hemodynamic alterations, development of dysrhythmias during MV and weaning and subsequent impact on length of MV has received little attention. The purposes of this dissertation were to 1) evaluate the relationship of heart rate variability (HRV) during weaning to the development of cardiac dysrhythmias and 2) determine the relationship of cardiac dysrhythmias to length of MV. A convenience sample of 35 patients (66.7% men; mean age 53.3 years) who required MV was enrolled in this study. Continuous 3-lead electrocardiographic data were collected for 24 hours at baseline during MV and for the first 2 hours during the initial weaning trial. HRV was evaluated using spectral power analysis. Twenty- seven patients out of 30 were exposed to a combination of pressure support (8-15 cm H2O) and continuous positive airway pressure 5 cm H2O during weaning trial. Three patients self- extubated and received supplemental oxygen through either a partial rebreathing or non-rebreathing mask. Low frequency (LF) power HRV decreased, while high frequency (HF) and very low frequency (VLF) power HRV did not change during weaning. Multiple regression analyses showed that LF and HF HRV were significant predictors of occurrence of ventricular and supraventricular ectopic beats during weaning, while VLF power predicted occurrence of ventricular ectopic beats only. The mean of occurrence of supraventricular ectopic beats per hour during weaning was double the mean at baseline, while the mean of ventricular ectopic beats per hour did not change. Mean number of supraventricular ectopic beats per hour during weaning was a significant predictor of length of MV. This dissertation has fulfilled an important gap in the evidence base for cardiac dysrhythmias during weaning from MV. Cardiac dysrhythmias and HRV alterations should be systemically evaluated during MV and weaning trials in order to decrease length of MV.
95

A CONTROLLED COMPARISON OF EMOTIONAL REACTIVITY AND PHYSIOLOGICAL RESPONSE IN CHRONIC OROFACIAL PAIN PATIENTS

Schmidt, John E 01 January 2007 (has links)
This study examined the emotional and physiological differences between masticatory muscle pain patients and age, height, and weight matched pain-free controls. Physiological activation and emotional reactivity were assessed in the 22 muscle pain patients and 23 pain-free controls during a baseline rest period, while discussing a personally relevant stressor, and during a post-stressor recovery period. Physiological activity was assessed through the use of the frequency domain heart rate variability indices. Activity in the high frequency heart rate variability range is an index of parasympathetic activity while activity in the low frequency heart rate variability range is an index of both sympathetic and parasympathetic activity (Akselrod, 1981). The muscle pain patients showed significantly more physiological activation during both the baseline rest and the post-stressor recovery periods. These physiological differences were quantified by higher low frequency heart rate variability and lower high frequency heart rate variability during these study periods. This pattern of higher activation was also present in the report of emotional reactivity in the muscle pain patients. The emotional and physiological differences between the groups across study periods were more pronounced in muscle pain patients who reported a traumatic life experience. These results provide evidence of physiological activation and emotional responding in masticatory muscle pain patients that differentiates them from matched pain-free controls. The use of HRV indices to measure physiological functioning quantifies the degree of sympathetic and parasympathetic activation. Study results suggest the use of these HRV indices will improve understanding of the role that excitatory and inhibitory mechanisms play in the onset and maintenance of chronic masticatory muscle pain conditions.
96

SELF-REGULATION IN OLDER ADULTS: THE PRIORITIZATION OF EMOTION REGULATION

Evans, Daniel R 01 January 2014 (has links)
Despite having fewer cognitive resources, older adults regulate their emotions as well as, if not better than, younger adults. This study aimed to (1) test the limits of older adults’ emotion regulation capacity and (2) gain a better understanding of how older adults use their more limited resources to regulate their emotions. Participants included 48 healthy older adults aged 65-85 from the community and 50 healthy younger adults aged 18-25 from the student population. They were randomly assigned to one of four experimental groups involving an initial activity that was high or low in self-regulatory demand followed by a test task of emotion regulation or attention regulation. As expected, older adults performed equally as well as younger adults on the emotion regulation test task, though worse on the attention regulation test task. Using resting heart rate variability (HRV) as a physiological measure of self-regulatory capacity, older adults appeared to allocate more resources toward the emotion regulation task compared to the attention regulation task, and relative to younger adults. The results suggest that older adults maintain their emotion regulation capacity in part by allocating more resources toward emotion regulation goals.
97

RELATIONSHIPS AMONG PAIN THRESHOLD, SELF-REGULATION, EXECUTIVE FUNCTIONING, AND AUTONOMIC ACTIVITY: A GENERAL INHIBITORY SYSTEM PERSPECTIVE

Boggero, Ian Andres 01 January 2013 (has links)
Chronic pain patients have poorer pain inhibition, self-regulatory ability, executive functioning and autonomic inhibition than those without pain, supporting the view that suppressing pain is mentally taxing. In the current study, an alternate explanation was proposed; namely, that pain inhibition, self-regulation, executive functions, and heart rate variability (HRV) are all controlled by the same general inhibitory system. To test this hypothesis, participants came into the laboratory for three sessions. At the first session, individual differences in pain thresholds, self-regulatory strength, executive functioning, and HRV were measured. At the second and third sessions, self-regulatory persistence and within-session changes in pain thresholds were measured under conditions of high and low self-regulatory fatigue. Results revealed that those low in inhibitory strength, operationalized as the aggregate of pain inhibition, self-regulation, executive functioning, and HRV, became more sensitive to pain under conditions of self-regulatory fatigue, whereas no significant changes in pain threshold were found for those high in inhibitory strength. Additional analyses revealed that high baseline pain threshold marginally protected against the effects of self-regulatory fatigue. The findings provide some support for a general inhibitory system and suggest that physiological inhibition of pain and autonomic activity may be influenced by phasic self-regulatory fatigue.
98

Avaliação cardíaca de cães com cinomose / Cardiac evaluation of dogs with distemper

Araujo, Juliana Bornhausen Cardoso 09 November 2017 (has links)
Submitted by Juliana Bornhausen Cardoso de Araujo null (jubsaraujo@gmail.com) on 2017-12-11T01:42:29Z No. of bitstreams: 1 defesa cest fini 10.12 c alteracoes v2.pdf: 1290180 bytes, checksum: eaea0777a91ea4b787d719a382f3dade (MD5) / Submitted by Juliana Bornhausen Cardoso de Araujo null (jubsaraujo@gmail.com) on 2017-12-11T18:47:11Z No. of bitstreams: 1 defesa cest fini 10.12 c alteracoes v2.pdf: 1290180 bytes, checksum: eaea0777a91ea4b787d719a382f3dade (MD5) / Approved for entry into archive by ROSANGELA APARECIDA LOBO null (rosangelalobo@btu.unesp.br) on 2017-12-12T12:42:54Z (GMT) No. of bitstreams: 1 araujo_jbc_me_bot.pdf: 1238650 bytes, checksum: 89edb88921e475bb18deb582a11ed4dd (MD5) / Made available in DSpace on 2017-12-12T12:42:55Z (GMT). No. of bitstreams: 1 araujo_jbc_me_bot.pdf: 1238650 bytes, checksum: 89edb88921e475bb18deb582a11ed4dd (MD5) Previous issue date: 2017-11-09 / A cinomose é uma relevante doença infectocontagiosa no Brasil e possui um crescente número de mortes em sua decorrência. É comprovado que esta doença causa importantes alterações histopatológicas cardíacas, porém seus efeitos sobre o sistema cardiovascular foram pouco descritos. O presente estudo teve como objetivo avaliar a atividade do vírus no coração por meio da ecocardiografia, da eletrocardiografia e da monitorização eletrocardiográfica ambulatorial, mais conhecida como método Holter. / Distemper is an important infectious disease in Brazil that unfortunately has a crescent death toll. It has been proven that the virus has important histopathologic effects over the cardiovascular system although that has been scarcely researched. The present study has the objective of evaluating the virus’s activity on the heart with the help of echocardiography, electrocardiography and Holter. The ambulatory electrocardiographic monitoring, also known as Holter exam, is an effective way of detecting cardiac arrhythmias and sometimes can help with early detection of cardiac lesions.
99

Unravelling the links between psychotic-like experiences, sleep and circadian rhythms

Cosgrave, Jan January 2017 (has links)
Psychotic-like experiences (PLEs) are prevalent occurrences deemed comparable with the symptoms of psychosis, but not sufficiently severe to warrant a diagnosis upon clinical presentation. Their presence is associated with several adverse clinical outcomes: the onset of various common mental health disorders (e.g. anxiety, mood, substance abuse), poorer functioning, non-remission and relapse. Sleep and circadian rhythm disruption (SCRD) is observed in 30-80% of patients with psychosis. The omnipotence of SCRD across all phases of the disorder (including the prodromal, acute, chronic and residual phases) raises the question as to whether SCRD may directly contribute to the development of psychosis. Assuming that PLEs are along the same continuum to developing psychosis, a logical next step to further disentangle the sleep-psychosis relationship is to examine whether SCRD relates to the experience of PLEs and whether this relationship is bi-directional. This thesis begins by examining the core predictions made by a continuum model of understanding psychosis and how specific parameters of sleep may influence PLEs. A smaller high-definition cross-sectional study follows, examining biological underpinnings (electroencephalography (EEG), electrocardiography (ECG), endogenous melatonin rhythms and actigraphy) of a complaint of poor sleep and their relation to the occurrence of PLEs. We then refocus on which parameters of sleep are most integral to the sleep-PLE relationship and close with an investigation of how Hypothalamic Pituitary Adrenal (HPA) axis activity may further our knowledge of this relationship. The findings of this thesis demonstrate specificity in the parameters of sleep shown to impact certain PLEs. The importance of objective sleep and biologically driven measures in this line of research are underscored, with group differences in EEG, ECG and melatonin. This thesis also highlights dissociative symptomatology as a candidate mediator for the sleep-psychosis relationship, and emphasises the ties between paranoia and negative affect. Finally, this thesis also illuminates the challenges of examining the relationship between sleep and PLEs in isolation, and suggests that they must be considered within the broader framework of co-existing mental health problems.
100

Avaliação do efeito da administração de piridostigmina sobre a variabilidade da frequência cardíaca em pacientes portadores de diabetes mellitus tipo 2 com neuropatia autonômica cardiovascular

Harthmann, Ângela d'Avila January 2010 (has links)
Objetivos/Hipótese: A Piridostigmina bloqueia a acetilcolinesterase, promove estimulação colinérgica e aumenta a variabilidade da freqüência cardíaca (VFC) em indivíduos saudáveis e com insuficiência cardíaca. Os efeitos sobre a modulação autonômica no diabetes mellitus tipo 2 (DM2) são desconhecidos. Nós testamos a hipótese de que a administração de piridostigmina aumenta a VFC em pacientes com DM2 e neuropatia autonômica cardiovascular (NAC). Métodos: Estudamos 34 pacientes com DM2 e NAC com idade entre 30 e 70 anos. Dezessete receberam 30 mg de piridostigmina via oral, de 8/8h por 24h (PI) e 17 receberam placebo (PL). A VFC foi avaliada pela média (RRMed) e desvio padrão dos intervalos RR (SDNN), pela raiz quadrada da média das diferenças sucessivas entre intervalos RR (RMSSD) e pelos índices do Mapa de Retorno Tridimensional P1, P2, P3 e MN. Resultados: Não houve diferenças significativas entre os grupos PI e PL quanto às características clínicas basais e à VFC sob efeito de piridostigmina e PL (RRMed - 748 ± 99 vs 733 ± 111ms; SDNN - 107 ± 26 vs 108 ± 36ms; RRMSD - 20,7 ± 12,7 vs 20,3 ± 10ms; P1 - 63 ± 11 vs 69 ± 14; P2 - 66 ±13 vs 63 ± 15; P3 - 86 ± 34 vs 80 ± 24 e MN - 392 ± 241 vs 369 ± 185). Conclusão: A piridostigmina não modifica a VFC em pacientes com DM2 e NAC. / Aims/Hypothesis: Pyridostigmine blocks acetylcholinesterase, promotes cholinergic stimulation and increases heart rate variability (HRV) in healthy individuals and with cardiac heart failure. The effects on the autonomic modulation in diabetes mellitus type 2 (DM2) are unknown. We have tested the hypothesis that the administration of pyridostigmine increases HRV in DM2 and CAN patients (CAN). Methods: We have studied 34 DM2 and CAN patients aged between 30 and 70 years old. Seventeen received 30mg of pyridostigmine via oral administration, every 8 hours during 24 hours (PY) and 17 received placebo (PL). HRV was assessed by the mean of all normal R-R intervals RR (mean RR) and the standard deviation of all normal R-R intervals (SDNN), by the root-mean-square of successive differences (RMSSD) and by the three-dimensional return map indices P1, P2, P3 and MN. Results: There were no significant differences between the PY and PL groups as to the baseline clinical characteristics and to HRV under the effect of pyridostigmine and PL (mean RR - 748 ± 99 vs 733 ± 111ms; SDNN - 107 ± 26 vs 108 ± 36ms; RRMSD - 20,7 ± 12,7 vs 20,3 ± 10ms; P1 - 63 ± 11 vs 69 ± 14; P2 - 66 ±13 vs 63 ± 15; P3 - 86 ± 34 vs 80 ± 24 e MN - 392 ± 241 vs 369 ± 185). Conclusion: Pyridostigmine does not modify HRV in DM2 and CAN patients.

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