Introdução: A privação de sono (PdS) tem sido utilizada como um estratégia alternativa para o tratamento do Transtorno Depressivo Maior (TDM), contudo sua eficácia e efetividade carecem de estudos homogêneos e de bom delinemento para dar um grau de evidência científica para seu uso na prática diária. Assim sendo, desde a primeira publicação, em 1971, num relato de caso de um paciente com TDM grave tipo melancólico, por Plug e Tölle, o mesmo estava assintomático no dia seguinte à privação total de sono. Contudo, na noite seguinte de sono seus sintomas depressivos retornaram. Nestes quase 40 anos desde esta publicação houve dezenas de estudos em sua maioria relatos de caso, série de casos ou até estudos abertos só que misturando pacientes com TDM com Depressão Bipolar sem mesmo distinguir se tipo I ou II. A cafeína com seu efeito estimulador poderia ser uma alternativa para facilitar a privação de sono. No entanto, não há dados sobre o sua potencial influência no efeito antidepressivo da PdS. O objetivo deste estudo é avaliar o efeito da cafeína na PdS em pacientes deprimidos unipolares moderados a graves não psicóticos. Métodos: Ensaio Clínico randomizado, duplo cego, cruzado, comparando cafeína contra placebo em pacientes deprimidos moderados a graves submetidos à privação total de sono (PdS). Os pacientes foram avaliados por itens da escala de Lader, HAMD- 6 itens, CGI Severidade e Melhora Global. Resultados: Foram avaliados 20 pacientes. Os pacientes que usaram cafeína mantiveram o mesmo escore de energia pré e pós-privação de sono (item energético-letárgico da escala de Lader) enquanto os do grupo placebo diminuíram o escore de energia pós-privação de sono. (p = 0,0045). Não houve diferença entre o grupo cafeína e placebo nos demais itens da escala de Lader. Conclusão: O uso combinado de cafeína e PdS pode ser uma estratégia útil para manter os pacientes mais acordados sem o prejuízo do cansaço da PdS em pacientes ambulatoriais deprimidos. Contudo, mais estudos envolvendo pacientes que tenham 10 respondido à PdS são necessários para verificar se a cafeína também não interfere nos resultados deste grupo. / Introduction: Sleep deprivation (SD) has been used as an alternative approach to treat major depressive disorder (MDD), however the efficacy and the effectiveness needs studies with homogeneity and better delineament to strengthen the evidence based medicine to the use in the practical daily use. Besides, since the 1° puplication in 1971 of a case report, by Plug and Tölle, in that one patient with severe melancholic depressive disorder achieved remission in the next day after a total sleep deprivation. However his depressive sintomtology was back after the next night of sleep. Since this almost 40 years, a lot of papers were puplished, and the majority where case report, case reports and open trials with patients with MDD, bipolar depression without make difference between tipe I or II. Caffeine, due to its stimulating effect, could be an alternative to promote sleep deprivation. However, there are no data about its potential influence on the antidepressive effect of SD. The objective of this study is to assess the effect of caffeine on SD in non-psychotic patients with moderate to severe unipolar depression. Methods: Randomized, double-blind, crossover clinical trial comparing caffeine and placebo in moderate to severe depressed patients who underwent total sleep deprivation (SD). The patients were assessed with items of the Bond-Lader Scale, the 6-item Hamilton Depression Rating Scale (HAMD-6), and the Clinical Global Impression (CGI)-Severity/Improvement. Results: Twenty patients participated in this study. The patients who consumed caffeine presented the same score of energy before and after sleep deprivation (lethargicenergetic item of the Bond-Lader scale), while the patients in the placebo group had a reduced score of energy after sleep deprivation (p = 0.0045). There was no difference between the caffeine and placebo groups in the other items of the Bond-Lader scale. Conclusion: The combined use of caffeine and SD can be a useful strategy to keep the 12 patient awake without impairing the effect of SD on depressed outpatients. However, further studies involving patients who have responded to SD are needed in order to verify if caffeine also does not interfere with the results in this group.

- / Doctorat en Sciences Psychologiques et de l'éducation / info:eu-repo/semantics/nonPublished

Submitted in fulfilment of the requirements for the Degree of Masters in Technology: Environmental Health, Durban University of Technology, 2017. / Shift work is a necessity for many organizations. Reasons for shift work are mainly to ensure continuous and optimized operations. Many studies on shift workers have concluded that it can lead to adverse physiological, social and psychological health effects. This study examines challenges associated with working shifts at a biscuits manufacturing factory. Results should be able to assist the employer in implementing effective interventions directed at limiting the negative effects of shift work on employees. This is a convergent parallel design multi method stud among 152 shift workers in a biscuits manufacturer located in Durban, KwaZulu Natal. An abbreviated and modified form of the validated SSI questionnaire was used (Barton et al. 1995). The questionnaire contained a battery of items designed to examine the relationship of health and personal adjustment to shift work. Owing to the exploratory nature of the study, a focus group methodology was also used and this allowed for in-depth qualitative research which catered for a more comprehensive understanding of the current shift work issues. A retrospective review of injury records of employees who sustained occupational injuries between 2012 and 2013 was also conducted. The sample comprised of 85 (56%) males and 63 (42%) females. Logistic regression was used to estimate the association between shift work and the likelihood of sleep disturbance, poor health outcomes and limited time for social and domestic activities, adjusting for age, sex, partner working, years working night shift, marital status, job class and years employed. Odds ratio (OR) for reported sleep disturbance was slightly higher among women (OR=1.65; 95% CI = 0.25; 10.84; p < 0.05) compared to males, but this was not statistically significant. Longer shift work experience (i.e.11-20 years) was significantly associated with better health status (OR=0.18; 95%CI = 0.06; 0.46; p < 0.05). Shift work experience (11 to 20 years) was also found to be significantly associated with limited time for both social (OR = 0.10; 95%CI = 0.03; 0.30) and domestic activities (OR= 0.25; 95% CI = 0.11; 0.57; p < 0.05) (Table 4). Age had no effect on social and domestic activities, but those 40 years and above were more likely to have limited time for social and domestic activities (OR = 3.06; 95%CI =0.60; 15.60 and OR= 2.5; 95%CI=0.47; 13.06). Those with more shift work experience seemed to have more time for social and domestic activities compared to those with less than 10 years experience. Findings from the FGD’s revealed that most participants (91%) did not get sufficient sleep time after night shift; this was mainly because of the chores they had to do after getting home form night shift and disturbances from the household and neighbours. The average time spent sleeping by majority of participants after night shift was 5 hours. Swollen feet, gastric, sleep disorders, indigestion and headaches were some common complaints experienced by shift workers in this study. About 27% of participants reported to have been injured at work before. These incidents were reported to be related to drowsiness and fatigue. The company’s incident records showed a total of 160 injuires between 2012 and 2013, of which 38 occurred during night shift. In 2012, the company recorded 65 injuries which included 51 first aid (FA) injuries, 6 minor injuries (MI) and 8 lost time (LT) injuries, as categorized by the company. 2013 had the highest number of incidents, with 95 total injuries, averaging to 7.9 injuries annually. There were 84 first aid incidents recorded for year 2013, 9 minor injuries and only 2 lost time injuries. Twenty three percent (15, n=65) incidents occurred during night shift in year 2012, of which 11% (7, n=65) were females. The number of night shift incidents slightly increased to 24% (23, n=95) in 2013 and females accounted for 9.40%. The records showed that majority of injuries happened between 17h00 and 21h00 at night. Results of this study provides evidence that shift work impacts negatively on the lives of the employees and can lead to adverse health outcomes such as poor dietary intake, headaches and swollen feet to mention but a few. / M

La problématique de la performance des marins en navigation extrême, n’a été que très peu étudiée avec des méthodes scientifiques rigoureuses de façon systématique et sous un angle de vue global en conditions écologiques. Nos travaux se sont attachés à évaluer le comportement humain en conditions écologiques avec une approche environnementaliste et transactionnelle. L’objectif principal de cette thèse a été de comprendre quel est l’impact des facteurs environnementaux tels que la force du vent et la quantité de sommeil ainsi que d’une stimulation cognitive à l’aide d’un vidéo self-modeling sur la perception de l’anxiété, de la fatigue et la tolérance à l’effort à vitesse maximale aérobie. Les résultats de la première étude, en condition écologique, où l’influence du vent et de la privation du sommeil ont été modélisées grâce à l’outil des fonctions transferts, a permis de comprendre que le marin opère une régulation liée temporellement à son engagement et aux efforts ou privations comme par exemple celle du sommeil. Cette régulation est liée à la perception de l’anxiété et l’intensité de l’effort perçu et est influencée par les facteurs environnementaux comme le vent ou la privation de sommeil. Cette étude a aussi montré qu’il existe une relation entre la durée de l’engagement, mesurée par le nombre de jours passés en mer, et la quantité de sommeil nécessaire, permettant ainsi de résister aux conditions environnementales. Une seconde étude en milieu extrême, cette fois en équipage de deux personnes, en utilisant le même protocole a confirmé que la quantité de sommeil était le meilleur activateur pouvant agir sur l’anxiété et permettre au mieux sa régulation. Une troisième étude nous a permis de montrer que la tolérance à un effort, mesuré par la perception de l’effort, n’était pas couplée exclusivement à une réponse physiologique mais aussi à des facteurs cognitifs. Le résultat principal de cette étude pilote a été de montrer que l’utilisation du feedback vidéo comme stimulation cognitive diminue significativement la perception de l’effort à partir 50% de la durée de l’épreuve. Contrairement à ce qui aurait pu être attendu, aucun effet n’a été observé sur la fréquence cardiaque. L’ensemble de ces résultats tend à montrer l’importance de l’interaction environnement – individu en milieu extrême, ainsi que lors d’une épreuve menée jusqu’aux limites de l’épuisement. Ces résultats ouvrent des perspectives intéressantes dans les domaines de l’entraînement sportif et de la rééducation. / The problem of performance in extreme sailing navigation has been very little studied using rigorous scientific methods consistently and at an angle of view in global environmental conditions. Our work sought to evaluate human behavior in ecological conditions with environmentalist and transactional approach. The main objective of this thesis was to understand what the impact of environmental factors such as wind strength and the amount of sleep as well as cognitive stimulation using a video self-modeling on perception of anxiety, fatigue and exercise tolerance in maximal aerobic speed. The results of the first study, ecological condition, where the influence of wind and sleep deprivation were modeled using the tool transfers functions, has to understand that the sailor makes a time- dependent regulation of its commitment and efforts and hardships such as that of sleep. This regulation is related to the perception of anxiety and intensity of perceived fatigue and is influenced by environmental factors such as wind or sleep deprivation. This study also showed that there is a relationship between the duration of the engagement, as measured by the number of days at sea, and the amount of sleep needed, allowing withstand environmental conditions. A second study in extreme conditions, this time with a crew of two people using the same protocol confirmed that the amount of sleep was the best activator can act on anxiety and allow its better regulation. A third study, we showed that the tolerance to stress, as measured by perceived exertion, was not exclusively coupled to a physiological response but also cognitive factors. The main result of this pilot study was to show that the use of video feedback as cognitive stimulation significantly reduces the perception of effort from 50 % of the duration of the event. Contrary to what might be expected, no effect was observed on heart rate. All of these results suggest the importance of the interaction environment - individual in extreme environments, and in a test conducted to the limits of exhaustion. These results open interesting perspectives in the fields of sports training and rehabilitation.

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Modern day society is vastly complex, with information and data constantly being posted, shared, and collected everywhere. There is often an abundance of massive amounts of unlabeled data that can not be leveraged in a supervised machine learning context. Thus, there exists an incentive to research and develop machine learning methods which can learn without labels. Selfsupervised learning (SSL) is a newly emerged machine learning paradigm that aims to learn representations that can later be used in domain specific downstream tasks. In this degree project three SSL models based on the Simple Framework for Contrastive Learning of Visual Representations (SimCLR) are evaluated. Each model aims to learn sleep deprivation related representations on magnetoencephalography (MEG) measurements. MEG is a non-invasive neuroimaging technique that is used on humans to investigate neuronal activity. The data was acquired through a collaboration with Karolinska Institutet and Stockholm University, where the SLEMEG project was conducted to study the neurophysiological response to partial sleep deprivation. The features extracted by the SSL-models are analyzed both qualitatively and quantitatively, and also used to perform classification and regression tasks on subject labels. The results show that the evaluated Signal- and Recording SimCLR models can learn sleep deprivation related features, whilst simultaneously learning other co-occuring information also. Furthermore, the results indicate that the learned representations are informative and can be utilized for multiple downstream tasks. However, it is noted that what has been learned is mostly related to subject-specific individual variance, which leads to poor generalization performance on classification and regression downstream tasks. Thus, it is believed that the models would perform better with access to more MEG data, and that source localized MEG data could remove part of the individual variance that is learned. / Den moderna dagens samhälle är enormt komplext, information och data blir konstant postat, delat, och insamlat överallt. På grund av det så finns det ofta ett överflöd av massiva mängder omärkt data some inte kan användas i ett övervakat maskininlärnings-sammanhang. Därmed finns det ett incitament att forska om och utveckla maskininlärningsmetoder som kan lära modeller utan tillgång till märkningar. Självövervakad inlärning (SSL) är en modern metod som nyligen har fått mycket fokus, vars mål är att lära sig representationer av datat som sedan kan användas i domänspecifika nedströmsuppgifter. I det här examensarbetet så är tre SSL metoder evaluerade där de alla strävar efter att lära sig representationer relaterat till sömndeprivering på magnetoencefalografi (MEG) mätningar. MEG är en icke-invasiv metod som används på människor för att undersöka neuronal aktivitet. Datat var förvärvat genom ett sammarbeta med Karolinska Institutet och Stockholms Universitet, där SLEMEG studien hade blivit genomförd för att studera neurofysiologisk respons på sömndeprivering. De av SSL-modellerna extraherade särdragen är analyserade både kvalitativt samt kvantitativt, och sedan använda för att genomföra klassificerings och regressions-uppgifter. Resultaten visar på att de evaluerade Signal- och Recording SimCLR modellerna kan lära sig särdrag relaterade till sömndepriverad, men samtidigt också lära sig annan samförekommande information. Dessutom så indikerar resultaten att de lärda representationerna är informativa och kan då användas i flera olika nedströmsuppgifter. Dock så noteras det att det som blivit inlärt är mestadels relaterat till individ-specifik varians, vilket leder till dålig generaliseringsprestanda. Således är det trott att modellerna hade presterat bättre med tillgång till mer MEG data, samt att källlokalisering av MEG datat hade kunnat ta bort en del av den individuella variansen som blir inlärd.

睡眠是否能鞏固陳述性記憶目前尚無定論。過去研究一致較支持睡眠能增進相關字詞配對的學習，但睡眠是否能增進無關字詞配對的學習，目前仍存在不一致的發現。造成該差異的原因可能是：過去研究多採用的行為測量指標，或許無法充分反映出睡眠促進記憶新聯結（new association）產生的效果。事件關聯電位（Event-related potential, ERP）的N400反映出語意記憶系統內每個字詞彼此的相關程度，因此本研究使用N400來探討睡眠強化無關字詞配對形成新聯結的電生理歷程。30名健康受試者（15位男性與15位女性，平均年齡為20.7歲） 隨機分派至睡眠組或清醒組，第一晚在學習80組無關字詞配對後，接受第一次再認記憶測驗，同時進行ERP的記錄。隨後睡眠組接受睡眠記錄（PSG），清醒組則接受整晚的睡眠剝奪，兩組受試者皆在第二晚給予8小時的躺床時間，使他們有機會充足睡眠以恢復精神，於第三天早上接受第二次再認記憶測驗及ERP記錄。在記憶測驗時，無關字詞配對分別組成促發字（prime）與目標字（target）先後出現，受試者需判斷先後出現的字詞是否為先前學過的完整配對，在測試階段同時記錄腦電波訊號。行為測量結果顯示睡眠過後，再認表現的正確率顯著提高且反應時間明顯縮短，但在睡眠剝奪後則顯示相反的結果。電生理測量發現睡眠組的N400振幅在睡眠過後較清醒組明顯降低。另外，睡眠組較清醒組有較高的正確率與較短的反應時間。睡眠組再認測驗的進步量與慢波睡眠呈現負相關，而慢波睡眠與第一次再認測驗的正確率呈現正相關，根據二階段睡眠記憶鞏固理論，慢波睡眠涉及重新組織記憶的歷程（系統性固化），因此學習表現較佳的受試者出現較多的深度睡眠，可能反應其經歷系統性固化。本研究結果顯示睡眠對於產生新聯結有明顯的增強效果，而且慢波睡眠可能參與了記憶表徵重新分配的歷程。 / The effect of sleep on declarative memory remains contradictory. Prior studies show that sleep benefits the learning of related word pairs consistently, while the learning of unrelated word pairs, however, show mixed results. It is possible that the behavioral measures used in previous studies are not sensitive enough to reveal subtle effects of sleep on new associations. N400, an event-related potential (ERP) component reflecting relatedness among words in semantic memory, was used in the present study to investigate the effect of sleep on the physiological process underlying new associations of unrelated word pairs. Participants were randomly assigned to either a Sleep group or a Wakefulness group. In the learning phase, participants were asked to memorize 80 visually presented unrelated word-pairs, followed by a pre-test phase with a recognition task. The participants then underwent either a night of nocturnal sleep (Sleep group) or sleep deprivation (Wakefulness group). A post-test was conducted after subjects had one night of recovery sleep. During both pre-test and post-test sessions, prime and target words were presented successively for the subjects to judge whether they were among the original pairs or new pairs. ERPs were recorded during both test phases. The behavioral data show that differences in improvement of recognition and decreases in reaction time from pre-test to post-test are significant between Sleep and Wakefulness groups. N400 peak amplitude attenuated significantly after sleep but not after wakefulness. The improvement of recognition negatively correlates with slow wave sleep (SWS). The number of word-pairs acquired in the learning phase, however, correlates positively with SWS. According to the two-stage memory consolidation theory of sleep, SWS involves in redistribution of memory (systematic consolidation). Therefore, that the participants with high performance showed more SWS may reflect the process of systematic consolidation. These results suggest that the sleep has an enhancing effect on the formation of novel association, and SWS may be involved in the process of redistributing memory representations.