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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.
31

An?lise da rela??o entre altera??es do padr?o do sono e dor lombo-p?lvica em mulheres no segundo trimestre gestacional

Sousa, Vanessa Patricia Soares de 06 December 2011 (has links)
Made available in DSpace on 2014-12-17T15:16:17Z (GMT). No. of bitstreams: 1 VanessaPSS_DISSERT.pdf: 1275710 bytes, checksum: b09cbd6ee567f69dfc8faff3fa50a56f (MD5) Previous issue date: 2011-12-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / A gravidez caracteriza-se por diversas mudan?as no corpo da mulher. Essas altera??es contribuem para o surgimento da dor lombo-p?lvica (DLP), a qual pode influenciar no sono durante o per?odo grav?dico. O objetivo desta pesquisa foi analisar a rela??o entre as altera??es do sono e a DLP em mulheres gr?vidas. Trinta volunt?rias, divididas em grupo controle (GC; n=15) sem DLP e grupo de estudo (GE; n=15) com DLP, com faixa et?ria entre 19 e 36 anos (M= 27,8; DP= ?3,5) e idade gestacional compreendida entre 14 e 26 (M= 19,8; DP= ?3,3) semanas, foram avaliadas quanto ao padr?o do sono, por meio do ?ndice de Qualidade do Sono de Pittsburgh, Escala de Sonol?ncia de Epworth e actimetria. A dor lombo-p?lvica foi analisada utilizando-se a Escala Visual Anal?gica (EVA) e o Oswestry Disability Index. Os dados foram analisados pelos testes de Kolmogorov-Smirnov, Qui-quadrado, Teste-t de Student para amostras independentes, ANOVA e an?lise de regress?o linear. Os principais resultados, relativos ao sono, mostraram piora da qualidade subjetiva (IQSPT - 10; ?3,7; p=0,034), diminui??o do tempo total (TTSACT - 5,7; ?1,0; p=0,022), efici?ncia (EFACT - 62,1; ?5,0; p=0,001) e aumento da lat?ncia (LSACT - 26,4; ?84,0; p=0,001) nas gestantes do GE, quando comparado ao GC. Al?m disso, constatou-se que varia??es crescentes na intensidade dolorosa interferem significativamente na IQSPT (p=0,001), TTSACT (p=0,001), EFACT (p=0,001). Os achados desse estudo sugerem que a dor lombo-p?lvica ? um fator potencializador das altera??es do padr?o de sono em mulheres gr?vidas
32

Objective assessment of sleep in neurodevelopmental disorders : a study of children with mucopolysaccharidosis type III

Mahon, Louise January 2012 (has links)
This thesis, which focuses on sleep disturbance in people with neurodevelopmental disabilities, is divided into three sections. Paper one is a systematic review of the extant literature on objective studies of sleep in neurodevelopmental genetic disorders. Twenty papers met inclusion criteria and were subject to quality assessment, of which five were found to be high-quality, thirteen were medium-quality and two were low-quality. Studies were grouped by disorder and although there was some disparity across investigations, generally there was agreement about specific sleep difficulties in each disorder which seem to be part of the behavioural phenotypes. Overall a lack of total sleep, diminished REM sleep, and fragmented, less efficient sleep are prevalent across the disorders. Paper two is an empirical study which employed actigraphy to assess sleep in children with mucopolysaccharidosis type III (MPS III) and typically developing children. Parents completed a sleep diary, a sleep questionnaire and took saliva samples from their child. Actigraphic findings showed that MPS III patients had lengthened sleep onset latencies and greater daytime sleep than controls, but night-time sleep duration was within the normal range. In the MPS III group, some sleep problems correlated with age and progression of the disorder. Analysis of saliva samples revealed that children with MPS III had abnormal melatonin concentrations. Questionnaire responses demonstrated that children with MPS III had more sleep difficulties in all domains compared to controls. Implications for the management of sleep difficulties are discussed. Paper three is a critical appraisal of the research process which includes personal reflections on designing and conducting this research and a discussion of the principal issues which arose. Strengths and limitations of the research, ideas for further research and implications for clinical practice are considered.
33

Sleep, pain and daytime functioning in patients with fibromyalgia syndrome and osteoarthritis : a cross-sectional comparative study

Yeung, Wai January 2016 (has links)
Fibromyalgia syndrome (FMS) is a disorder characterised by chronic widespread pain, non-restorative sleep, fatigue and daytime dysfunction. Occurring in 2-5% of the population, the aetiology is largely unknown. Sleep dysfunction occurs in over 90% of FMS patients. While research has shown that both the macrostructure and microstructure of sleep may be altered, there remain inconsistencies in the polysomnographic (PSG) findings, and wide variations in methodological approaches. Few studies have controlled for symptom duration or the time elapsed between diagnosis and PSG sleep assessments. In addition, while psychometric analyses have suggested a distinctive FMS psychological profile (which includes higher levels of depressive symptoms, anxiety and fatigue) few studies have simultaneously, and thoroughly examined sleep and psychological status in the same participants. A frequently reported alteration found in the sleep microstructure of FMS patients is the alpha-delta sleep anomaly, characterised by an increase in alpha wave activity during slow wave sleep. Originally considered a possible neurological contribution to FMS, whether the alpha-delta sleep anomaly is fundamental to the development of fibromyalgia syndrome, or results mainly from the pain experience of FMS patients remains unknown. No previous study has directly compared the sleep of FMS and other (non-FMS) patients experiencing similar levels of chronic pain and sleep dysfunction. The present study was designed to examine sleep macrostructure and microstructure in FMS patients, and evaluate the role of the alpha-delta sleep anomaly as either a possible contributor to fibromyalgia syndrome, or a likely consequence of pain experience. In order to explore these relationships, detailed sleep, activity and psychological profiles were compared in 3 groups: 1) FMS patients (n = 19); 2) osteoarthritis patients with sleep disturbance (n = 17); and non-clinical (normal healthy) adults (n = 10). In order to standardise diagnostic reliability and symptom chronicity, the FMS group was recruited from a single rheumatology facility immediately following diagnosis. Guided by a series of formal research questions, analyses compared sleep macrostructure (using American Academy of Sleep Medicine criteria), sleep microstructure (using spectral analysis), and a range of psychological variables (including pain experience, sleepiness, fatigue, depression, anxiety, perceived social support, health locus of control, pain catastrophizing and personality). The results indicated that the alpha-delta sleep anomaly is not unique to FMS, but appears to be a feature found in the sleep of normal healthy adults and (to a greater extent) those with FMS and osteoarthritis. The incidence of the anomaly was statistically similar in both clinical (FMS and osteoarthritis) groups, a pattern consistent of its being a secondary feature of pain, rather than a primary abnormality of FMS. Overall, the psychometric assessments of state and trait anxiety and depression better discriminated between the three groups than did the sleep variables. Nevertheless, on measures of sleep, perceived social support, health locus of control, and pain catastrophizing, FMS and osteoarthritis patients were not significantly different, though both clinical groups differed on these variables from healthy controls.
34

The Association of Sleep Quality and Loneliness with Perceived Physical and Mental Health Status in Autistic Adults

Russell, Nicholas Charles Clark 10 August 2020 (has links)
Autistic individuals report a greater prevalence of physical and mental health difficulties, compared to the general population. This study examines factors which impact physical and mental health in the general population to evaluate whether they potentially underlie this increased prevalence in autistic individuals. We compared twenty-two autistic adults, twenty-three adults reporting symptoms of insomnia, and twenty-one neurotypical adults. The primary factors were sleep quality and insomnia; secondary factors were level of autistic traits, alexithymia, and prosocial behavior. Participants completed self-report measures looking at each of these factors as well as their perceived physical and mental health. Participants also wore an actigraphy watch for up to fourteen days to characterize their sleep behavior. This actigraphy data suggested that autistic adults slept longer than those with symptoms of insomnia and the neurotypical group. Multiple regressions identified which primary or secondary factors were associated with change in perceived physical and mental health. Transdiagnostic dimensional analyses suggested that both lower sleep quality and higher levels of loneliness predicted lower perceived physical and mental health, with the effect being greater for perceived mental health. The addition of secondary factors identified higher levels of alexithymia as a significant predictor of lower levels of perceived mental health but did not improve the model. For the autistic group, no factors were predictive of change in perceived physical health; however, follow-up analyses identified more insomnia symptoms as predicting reduced perceived physical health. Both reduced sleep quality and greater loneliness predicted lower perceived mental health in the autistic adults. More sleep impairment and more symptoms of insomnia also predicted lower perceived mental health but did not better explain this change when included together over when included separately. These study findings suggest that sleep quality and loneliness are salient factors in the mental health of autistic adults and that understanding these, and sleep factors in general, may help to explain mental health challenges in these individuals.
35

Real Time Tracking of Sleep Behaviors as a Predictor of Suicidal Ideation for Young Adults with Autism Spectrum Disorder and Social Anxiety

Lograsso, Yong Seuk Steven 22 August 2023 (has links) (PDF)
Suicide continues to be a critical concern for society as one of the leading causes of death in the United States, increasing from 10.4 to 13.5 per 100,000 from 2000 to 2016. This risk is further increased up to 8 times for individuals with Autism Spectrum Disorder. Suicidal thoughts and behaviors have been difficult to predict on a moment-by-moment basis, in part due to technological challenges. Suicidal ideation has been identified as an important indicator of suicidal behavior and an important measurement for predicting suicide in both neurotypical individuals and individuals with autism spectrum disorder. In particular, sleep disturbances are one risk factor for suicidal behavior. Important aims of this study include identifying personalized predictors of leading up to suicidal ideation, including how sleep activity patterns affect suicidal ideation, and how these risk factors differ between those with autism spectrum, socially anxious groups. This will give further insight into predictors of suicidal ideation, providing a better understanding for predicting changes in suicidal ideation, with aims to bring more clarity in this at-risk population and improve treatment options. To observe predictors of both long-term and short-term changes in suicidal ideation, I will analyze longitudinal data. The data includes daily phone questionnaires and actigraphy data tracking using GENEActiv wearable devices that includes sleep from individuals with autism spectrum and social anxiety with a history of suicidal ideation, and neurotypical individuals who are tracked over 24-36 weeks. Results of analysis indicate that sleep duration is not a significant predictor of suicidal ideation intensity, and that there is no difference between the autism spectrum and social anxiety groups in the predictive ability of sleep. Limitations of this study include local convenience sampling which includes a large majority of white participants, part of the study and data collected occurring during the COVID-19 pandemic, and potential response bias for such a sensitive topic. This study shows overall that there is a working model for this type of analysis, however many more features of sleep including movement during sleep and waking during sleep need to be analyzed to see if there is any predictive power in information from actigraphy, which would be a low invasive method for detecting increases in suicidal ideation risk.
36

Temporal patterns of sleep disturbance, anxiety, and depressed mood in generalized anxiety disorder

Bullis, Jacqueline 04 December 2016 (has links)
Studies suggest that sleep disturbance may be an important etiological factor in the development of comorbid anxiety and depressive disorders, whereby anxiety leads to sleep difficulties, which in turn increase the vulnerability for depression. The primary aim of this study was to determine whether the sequential comorbidity patterns observed at the disorder level (i.e., where anxiety disorders most often precede insomnia, and insomnia most often precedes depression) were also present in daily fluctuations of symptoms. The secondary aim was to explore possible moderators of any observed temporal associations. Participants were 15 patients with generalized anxiety disorder (GAD; mean age = 28.9 years, SD = 9.8) and 15 good sleeper controls (mean age = 27.1 years, SD = 8.3) who were comparable in female:male ratio (73% female vs. 67% female). For 14 days, participants wore an actigraph to objectively assess sleep quality (sleep onset latency, total sleep time, wake after sleep onset, sleep efficiency) and completed daily symptom ratings multiple times each day using their smartphones to assess symptoms of anxiety, depressed mood, and subjective sleep quality. Study aims were assessed using multilevel modeling, with daily symptoms nested within individuals. Many of the analyses were lagged such that the time-varying predictor variable preceded the time-varying outcome variable temporally. Consistent with hypotheses, results demonstrated that anxious mood was predictive of later subjective and objective sleep disturbance in individuals with GAD, and this effect was strongest among individuals with higher levels of neuroticism, negative affect, and dysfunctional beliefs about sleep. Anxious mood was not associated with later subsequent sleep disturbance in healthy controls. In the GAD group, subjective and objective sleep disturbance predicted later depressed mood; this effect was moderated by temperament and dysfunctional beliefs about sleep. For the control group, the effect of subjective sleep disturbance on later depressed mood was moderated by neuroticism and the effect of objective sleep disturbance was moderated by dysfunctional beliefs about sleep, suggesting that sleep disturbance may increase vulnerability for depressed mood even in healthy individuals. These results suggest that explicitly targeting sleep disturbance during the treatment of GAD may attenuate the experience of depressive symptoms.
37

Biological Rhythms, Sleep and Cognition in Mood Disorders

Allega, Olivia January 2016 (has links)
This thesis presents research investigating the relationship between, and methods of, measuring circadian rhythms in mood disorders in a population of currently depressed and euthymic individuals with both depression and bipolar disorder. This was first assessed by comparing group differences in subjective sleep and circadian measures with objective sleep and circadian measures. The objective circadian measures involved actigraphy and melatonin profiling. This analysis showed group differences in subjective sleep and circadian parameters compared to controls, however no robust differences between mood groups. Objective melatonin profiling showed a mild agreement with subjective circadian parameters. Next, we studied the external validity of a subjective rating scale measuring biological rhythm disturbance, the Biological Rhythms Interview for Assessment in Neuropsychiatry (BRIAN), against objective measures of sleep and circadian activity rhythmicity. The BRIAN demonstrated some promising external validity, namely correlations with wake after sleep onset (WASO) and sleep efficiency, as well as melatonin levels in each group. These studies provide evidence of the extent to which a self-report may help in assessing parameters of sleep and circadian rhythms in the clinical setting. In doing so, it is expected that the use of subjective ratings will provide insight into the impact of biological rhythms disturbances and mood disorders. Lastly, we conducted an overview of the preclinical and clinical literature investigating the impact of circadian disturbance on cognitive performance. The results from this literature review yielded patterns of rhythmicity in specific parameters in each of the attention, memory, and executive function domains in humans, whereas attention and memory are more of a primary focus in animal studies. However, we also found that there are significant gaps in the understanding of how disturbances in circadian rhythms may influence cognitive function. This review also highlights the importance of cross-species translational validity from a methodological perspective, in order to generate positive clinical results beginning at the preclinical stage in neuropsychiatric disorders. / Thesis / Master of Science (MSc)
38

Effets de l’exposition au bruit des avions sur la qualité du sommeil des riverains des aéroports français / Effects of aircraft noise exposure on the sleep quality in the population living near airports in France

Nassur, Ali Mohamed 07 December 2018 (has links)
Contexte : Le trafic aérien, en constante augmentation au cours de ces dernières décennies, n'est pas sans impact sur l'environnement et la population. En particulier, le bruit émis par les avions constitue une nuisance importante et un problème majeur de santé publique, notamment en termes de perturbations du sommeil. Pour autant, en France surtout, les conséquences de l'exposition au bruit des avions restent insuffisamment évaluées. Objectif : L'objectif de ce travail de thèse est de mieux connaître et de mieux quantifier les effets du bruit des avions sur la qualité du sommeil des riverains des aéroports en France, en distinguant qualité subjective et qualité objective. Méthodes : Pour répondre aux objectifs de cette thèse, nous avons utilisé les données recueillies dans un programme de recherche épidémiologique appelé DEBATS (Discussion sur les Effets du Bruit des Aéronefs Touchant la Santé). L'étude principale, dite « étude longitudinale », a inclus 1244 participants vivant à proximité de trois aéroports français d'importance : Paris-Charles de Gaulle, Lyon-Saint Exupéry et Toulouse-Blagnac. La qualité subjective du sommeil a été évaluée grâce à un questionnaire administré par des enquêteurs au domicile des sujets. Le niveau d'exposition au bruit des avions a été estimé à l'adresse du domicile de chaque participant à partir des cartes de bruit produites par la Direction Générale de l'Aviation Civile. Une étude complémentaire dite « étude sommeil » a permis d'évaluer la qualité objective du sommeil de 112 des 1244 participants à l'étude longitudinale grâce au port d'un actimètre pendant huit jours et d'un Actiheart (enregistreur de la fréquence cardiaque) pendant une nuit. Des mesures acoustiques ont été réalisées pendant ces huit jours en façade et à l'intérieur de la chambre à coucher des participants, afin de caractériser leur exposition au bruit des avions à l'aide d'indicateurs non seulement énergétiques (LAeq, LA90) mais aussi événementiels (nombre d'événements et niveau maximum de bruit de l'évènement ou LAmax). Résultats : L'analyse de « l'étude longitudinale » a permis de montrer une association entre l'exposition au bruit des avions la nuit (Lnight) et la qualité subjective du sommeil caractérisée par un risque de déclarer dormir moins de 6 heures par nuit (OR=1,63 pour 10 dB(A) ; IC 95% : 1,15-2,32) et de se sentir fatigué au réveil (OR=1,23 pour 10 dB(A) ; IC 95% : 1,00-1,54). Nous n'avons pas trouvé de relation significative avec les autres paramètres subjectifs de la qualité du sommeil rapportés par les sujets eux-mêmes, tels que le temps d'endormissement, les éveils nocturnes, la satisfaction du sommeil et la prise de médicaments pour dormir. Nous avons également montré une association entre l'exposition au bruit des avions et les paramètres objectifs de la qualité du sommeil avec une augmentation du temps d'endormissement et de la durée des éveils intra-sommeil, une diminution de l'efficacité du sommeil, mais aussi une augmentation du temps total de sommeil et du temps passé au lit (cette dernière pouvant être interprétée comme un mécanisme d'adaptation à la privation de sommeil). Les indicateurs énergétiques, mais plus encore les indicateurs liés aux événements de bruit, sont significativement associés aux paramètres objectifs de la qualité du sommeil. Par exemple, les événements de bruit d'avions détectés à l'intérieur de la chambre à coucher sont associés à une augmentation de la durée totale des éveils intra-sommeil supérieure à 30 minutes (OR=1,10 pour 10 événements ; IC 95% : 1,03-1,16). Enfin, nous avons observé une augmentation significative de l'amplitude de la fréquence cardiaque pendant un évènement sonore associé au passage d'un avion et le niveau maximum de bruit de cet évènement (LAmax) [etc...] / Background: Air traffic, in constant increase during the last decades, is not without impact on the environment and the population. Aircraft noise in particular represents a serious nuisance and a major issue for public health, particularly in terms of sleep disturbances. However, in France especially, the effects of aircraft noise exposure remain insufficiently evaluated. Objectives: The objective of this PhD is to better know and better quantify the effects of aircraft noise exposure on sleep quality in populations living near airports in France, while distinguishing subjective quality and objective quality. Methods: In order to meet the objectives of the PhD, we used the data collected in an epidemiological research program called DEBATS (Discussion on the Health Effects of Aircraft Noise). The main study, also called the “longitudinal study”, included 1,244 participants living near three French major airports: Paris-Charles de Gaulle, Lyon-Saint-Exupéry and Toulouse-Blagnac. The subjective quality of sleep was assessed using a questionnaire administered by interviewers at the place of residence of the participants. Aircraft noise levels were estimated at each participant's home address using noise maps produced by the French Civil Aviation Authority. A complementary, also called the “sleep study” allowed us to estimate the objective sleep quality of 112 of the 1,244 participants in the longitudinal study. These 112 participants have worn a wrist actigraph for eight nights and an Actiheart (heart rate recorder) for one night. Acoustic measurements were made during these eight days and nights, both inside the participants’ bedrooms and outside (at the exterior façade) in order to characterize their aircraft noise exposure using not only energy indicators (LAeq, LA90) but also events indicators (number of events and maximum level of an noise event or LAmax). Results: The “longitudinaly study” analysis showed an association between aircraft noise exposure during the night (Lnight) and the subjective quality of sleep characterized by a risk of reporting to sleep less than 6 hours per night (OR=1.63 for 10 dB(A); 95% CI: 1.15–2.32) and a risk of feeling tired while awakening in the morning (OR=1.23 for 10 dB(A); 95% CI: 1.00– 1.54). We did not find any significant relationship with the other subjective parameters of sleep quality reported by the subjects themselves, such as time to fall asleep, nocturnal awakenings, sleep satisfaction, and sleep medication intake. We also showed an association between aircraft noise exposure and the objective parameters of sleep quality with an increase in time of sleep onset and duration of wake after sleep onset, and a reduction in sleep efficiency. Aircraft noise exposure also increased total sleep time and time in bed (this could be a matter of behavioral adaption to sleep deprivation). The energy indicators, but more still events indicators, were significantly associated with the objective parameters of sleep quality. For example, aircraft noise events detected inside the bedroom were associated with an increase in total duration of wake after sleep onset greater than 30 minutes (OR=1.10 for 10 events; 95% CI: 1.03-1.16). Finally, we observed a significant increase in amplitude of heart rate during a noise event associated with the passage of an aircraft and the maximum noise level of this event (LAmax). Conclusions: These results, mostly similar to those obtained in the majority of studies in the international literature, confirm that exposure to aircraft noise can decrease both subjective and objective quality of sleep. They also contribute to support the hypothesis that acoustic events indicators could, better than energy indicators more widely used, characterize the effects of aircraft noise on sleep
39

Sleep-Wake-Activity and Health-Related Quality of Life in Patients with Coronary Artery Disease and evaluation of an individualized non-pharmacological programme to promote self-care in sleep

Johansson, Anna January 2012 (has links)
Sleep is a basic need, important to physical and psychological recovery. Insomnia implies sleep-related complaints, such as difficulty falling asleep, difficulty staying asleep, early awakening, or non-restorative sleep (NRS) in an individual who has adequate circumstances and opportunity to sleep.  Insomnia is also related to impairment of daytime functions. The prevalence of reported sleep disturbances varies between 15% and 60% in patients with coronary artery disease (CAD) up to five years after intervention. Disturbed sleep may have a negative impact on self-care capacity and behaviours. Little attention has been given to evaluation of sleep promotion through individualized non-pharmacological interventions among CAD patients. The overall aim of this thesis was to describe the impact of sleep quality and disrupted sleep on health-related quality of life (HRQoL) in patients with stable CAD, in comparison to a population-based group. The objective was also to evaluate an individualized non-pharmacological programme to promote self-care in sleep. Four studies were conducted during seven years, starting in 2001. Patients from six hospitals in the south of Sweden were invited to participate. In addition, an age and gender matched population-based group was randomly selected during the same period as the patients and was used for comparison with the CAD patients in two of the studies. Data was collected through interviews, self-reported questionnaires, a study specific sleep diary and actigraphy registrations. A pretest-posttest control design was used to evaluate whether an individualized non-pharmacological intervention programme could promote self-care in sleep-activity in CAD patients. The results showed a high prevalence of insomniac CAD patients out of whom a large proportion were non-rested insomniacs. This showed that NRS is one of the core symptoms of insomnia. On the other hand there were weak or non-significant gender differences with increasing insomnia severity. Severe insomniac CAD patients displayed a two or threefold higher presleep arousal or anxiety score and were more limited in taking physical exercise than the general population. Generally low sleep efficiency (SE%) was revealed in the studies, particularly among severe non-rested insomniac CAD patients. Among CAD patients, the individualized non-pharmacological programme to promote self-care in sleep-activity indicated improvements in sleep and HRQoL. This thesis elucidates the importance of focusing on the individual’s perception of their sleep-activity and health in their local context and supporting self-care management. Furthermore, it is of importance that nurses set individual goals together with the patient in order to increase self-efficacy to promote HRQoL.
40

Estudo da organiza??o funcional do sistema circadiano por meio de ferramentas computacionais e matem?ticas / Gon?alves, bsb. study of the functional organization of the circadian system through computer modeling and analysis mathematics. Tese de doutorado em psicobiologia, ufrn, 137 p?ginas, 2013

Gon?alves, Bruno da Silva Brand?o 03 April 2013 (has links)
Made available in DSpace on 2014-12-17T15:36:40Z (GMT). No. of bitstreams: 1 BrunoSBG_DISSERT.pdf: 3965357 bytes, checksum: 7e3aabdd040d50db3f4557799b032b1d (MD5) Previous issue date: 2013-04-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Circadian rhythms are variations in physiological processes that help living beings to adapt to environmental cycles. These rhythms are generated and are synchronized to the dark light cycle through the suprachiasmatic nucleus. The integrity of circadian rhythmicity has great implication on human health. Currently it is known that disturbances in circadian rhythms are related to some problems of today such as obesity, propensity for certain types of cancer and mental disorders for example. The circadian rhythmicity can be studied through experiments with animal models and in humans directly. In this work we use computational models to gather experimental results from the literature and explain the results of our laboratory. Another focus of this study was to analyze data rhythms of activity and rest obtained experimentally. Here we made a review on the use of variables used to analyze these data and finally propose an update on how to calculate these variables. Our models were able to reproduce the main experimental results in the literature and provided explanations for the results of experiments performed in our laboratory. The new variables used to analyze the rhythm of activity and rest in humans were more efficient to describe the fragmentation and synchronization of this rhythm. Therefore, the work contributed improving existing tools for the study of circadian rhythms in mammals / Os ritmos circadianos s?o varia??es em processos fisiol?gicos que auxiliam os seres vivos na adapta??o aos ciclos ambientais. Esses ritmos s?o gerados e se sincronizam ao ciclo claro escuro por meio do n?cleo supraquiasm?tico. A integridade da ritmicidade circadiana tem grande implica??o na sa?de dos seres humanos. Atualmente sabe-se que dist?rbios nos ritmos circadianos est?o relacionados com alguns problemas da atualidade como a obesidade, propens?o a determinados tipos de c?ncer e transtornos mentais por exemplo. A ritmicidade circadiana pode ser estudada por meio de experimentos com modelos animais e diretamente nos seres humanos. Nesse trabalho utilizamos modelos computacionais para reunir resultados experimentais da literatura e explicar resultados de nosso laborat?rio. Outro foco desse trabalho foi na an?lise de dados de ritmos de atividade e repouso obtidos experimentalmente. Aqui fizemos uma revis?o sobre o uso de vari?veis utilizadas para analisar esses dados e por ?ltimo propomos uma atualiza??o na forma de calcular essas vari?veis. Os nossos modelos foram capazes de reproduzir os principais resultados experimentais da literatura e nos forneceram explica??es para resultados de experimentos realizados em nosso laborat?rio. As novas vari?veis utilizadas para analisar o ritmo de atividade e repouso em humanos se mostraram mais eficiente para descrever a fragmenta??o e sincroniza??o desse ritmo. Assim esse trabalho contribuiu aperfei?oando as ferramentas existentes para o estudo da ritmicidade circadiana nos mam?feros

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