In the decade before 2005, South African organisations have had to cope with an ever-increasing rate of local and global changes. There have been considerable and ongoing socio-political changes, resulting from new Government regulations. Most organisations have experienced some type of downturn, whether due to external business factors or poor internal performance. A typical response to organisational decline is retrenchment. Retrenchment is attributed to cyclical downturns, market losses or other economic factors, which oblige the employer to reduce the labour force numbers. Though there are so many ways of responding to organisational failure, this study focused only on retrenchment. A number of psychologists and human sciences researchers have studied the results of job loss due to retrenchment. Retrenchment brings loss of skills, loss of morale and commitment, as well as physical and mental health degradation, including stress that results in employees withdrawing physically and emotionally. The main purpose of this study was to outline the employees’ perceptions of the effects of retrenchment on job stress and organisational commitment in a mining company. The research methodology used in this study is a combination of a literature review and an empirical study. The probability sampling technique, which entails using simple random sampling, was used to select the sample of the study. The primary data were collected using a questionnaire. The measuring instrument contained 43 items. The measuring instrument was pilot-tested with 50 respondents three weeks before the main survey; the questionnaire was self-administered to the participants. For the main survey, data from 294 respondents were collected and analysed. Participants in the study involved surface employees, including management, administrators, engineers and artisans. Data were analysed with the Statistical Package for Social Sciences (SPSS) version 23.0. The Cronbach’s alpha coefficients of the various sections of the measuring instrument were computed to establish construct validity. Content validity was ascertained by pre-testing the questionnaire with the employees in the mine in question. Correlations were used to establish convergent validity of the constructs. Convergent validity was assessed to measure the degree of linear association of variables using Pearson’s correlation coefficient. Discriminant validity was achieved by using regression analysis to show items loaded onto different factors in various sections which had more than one factor. Analysis was done using descriptive statistics on the demographic information of respondents. The results were also interpreted through correlation and regression analysis. The results showed that the effects of retrenchment did not have a negative impact on job stress (time stress and anxiety). This may be due to the mine in question planning and consulting with the employees prior to the retrenchment process. The results also showed that job stress (time stress and anxiety) is negatively associated with organisational commitment. Subsequent to these findings, it is recommended that employees (survivors) be updated on their future in the company in question. This could be done through regular workshops and counselling of employees. In order to motivate and engage employees, and thereby contribute to employee commitment, it was also recommended that organisations create open, supportive and fair organisational and team cultures, and ensure jobs are clearly aligned with organisational goals and have appropriate levels of autonomy, support and career development. Given that job satisfaction plays a huge role in organisational commitment, it was further recommended that managers need to actively improve their organisation’s job satisfaction to employees in order to achieve a higher level of organisational commitment. The study concludes by recommending that communication between employees and management should take place on a regular basis which can serve as a fundamental tool to retrenchment in the following manner: • Survivors will feel more committed to the organisation when the basis of retrenchment addresses the circumstances in the external environment, rather than the enrichment of shareholders or top management. • Communicating a clear vision of how retrenchment will benefit stakeholders, increases commitment since survivors can see a clear future for the organisation. • When survivors are treated with dignity and respect, they will feel more committed to the organisation because they feel appreciated.

No description available.

Mental health professionals are at high risk of experiencing work-related stress and burnout due to the challenging and highly emotive environments in which they work. This may lead to a range of physical and psychological symptomology which may affect them and also the quality of care provided to patients. This thesis presents a systematic review of the literature regarding the effectiveness of workplace interventions designed to reduce or prevent work-related stress and burnout when compared to no intervention or alternative interventions for mental health professionals working in adult mental health settings. The thesis then presents an empirical study, using the Job Demands-Resources model of burnout. Personal resources (styles of coping, self-compassion, cognitive fusion and valued living) were tested as (a) moderators of the relationship between job demands and exhaustion and (b) mediators of the relationship between job resources and disengagement within a sample of mental health nurses. Methods: A systematic review and meta-analysis of randomised controlled trials (RCTs), non-randomised controlled trials (N-RCTs), controlled before and after (CBA) and interrupted time series workplace (ITS) interventions were conducted. Primary outcomes were occupational stress and burnout. An assessment of strength of evidence was made using GRADE criteria. A quantitative cross-sectional survey of 214 mental health nurses was used to examine the role of: self-compassion, cognitive fusion, engaged living and coping in the development of burnout. Results Thirteen eligible studies were identified comprising 11 RCTs and 2 CBA’s. Overall, there was no beneficial effect of organisational and relaxations intervention was found for reducing burnout or work-related stress. There are some promising findings for the effectiveness of staff training and psychosocial interventions in the short and medium-term. Overall, the quality of studies was low due to risk of bias and a lack of precision due to low number of participants in each study. In the empirical paper, the moderating role of personal resources in the development of exhaustion was not supported. By contrast the mediating role of personal resource between job resources and disengagement was supported. Discussion At present, there is limited evidence for the effectiveness of workplace interventions. This is influenced by the low number of intervention studies and the quality of interventions to date for mental health professionals. There is preliminary evidence for the potential for third-wave cognitive behavioural interventions such as acceptance commitment therapy in reducing disengagement in mental health nurses. Interventions to reduce exhaustion need to include strategies to reduce job demands.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Educação Física, Programa de Pós-Graduação Stricto Sensu em Educação Física, 2015. / Submitted by Albânia Cézar de Melo (albania@bce.unb.br) on 2016-01-05T14:23:06Z No. of bitstreams: 1 2015_RafaelGauche.pdf: 3313333 bytes, checksum: 1c2b862969484fe4800fda18a7aa636f (MD5) / Approved for entry into archive by Guimaraes Jacqueline(jacqueline.guimaraes@bce.unb.br) on 2016-01-06T11:30:51Z (GMT) No. of bitstreams: 1 2015_RafaelGauche.pdf: 3313333 bytes, checksum: 1c2b862969484fe4800fda18a7aa636f (MD5) / Made available in DSpace on 2016-01-06T11:30:51Z (GMT). No. of bitstreams: 1 2015_RafaelGauche.pdf: 3313333 bytes, checksum: 1c2b862969484fe4800fda18a7aa636f (MD5) / OBJETIVO: Verificar as respostas hemodinâmicas e autonômicas ao exercício resistido em idosas hipertensas medicadas, comparando-se os métodos tradicional e de circuito. METODOLOGIA: Dez mulheres idosas (71,1 ± 5,5 anos; 1,5 ± 0,1 m; 56,1 ± 9,8 kg; 24,2 ± 3,9 IMC) com hipertensão controlada participaram do estudo. As voluntárias foram submetidas a 4 sessões de familiarização e determinação de carga, e a 2 sessões experimentais de exercício resistido (tradicional e circuito). A carga foi determinada por meio da escala de percepção de esforço OMNI-RES, com o protocolo experimental composto por 3 séries de 12 repetições em 7 exercícios. A pressão arterial, a variabilidade da frequência cardíaca (VFC) e a reatividade pressórica ao estresse mental (teste de Stroop) foram avaliadas antes e após as sessões experimentais. Um teste t pareado foi utilizado para as comparações das variáveis hemodinâmicas e autonômicas de repouso e demais características das sessões experimentais. Análises de variância de medidas repetidas foram executadas para verificação dos efeitos dos dois métodos de exercício resistido na pressão arterial, VFC e reatividade da pressão arterial ao estresse mental. A significância estatística adotada foi de p < 0,05. RESULTADOS: O exercício resistido não promoveu alterações na pressão arterial pós-exercício para dos métodos estudados, em relação aos valores de repouso. Uma depressão vagal foi observada durante 15 minutos para a análise realizada no domínio de frequência da VFC, não confirmada por análise no domínio de tempo. A complexidade da frequência cardíaca foi reduzida por 45 minutos após o exercício, sem diferença entre as sessões. Pela primeira vez, foi verificada uma atenuação na reatividade da pressão arterial ao estresse mental após o exercício resistido, sem diferença entre os métodos estudados. Essa atenuação pode ser justificada, em parte, por uma redução na ativação simpática durante o estresse mediada pelo exercício. CONCLUSÕES: O exercício resistido é uma ferramenta eficaz na redução da reatividade pressórica ao estresse mental, o que pode estar associado a uma redução aguda no risco cardiovascular. Esses resultados apresentam implicação clínica de relevância, e se agregam a evidências prévias que recomendam essa modalidade de treino como importante componente de um programa de treinamento físico para idosos e para portadores da HA. __________________________________________________________________________________ ABSTRACT / OBJECTIVES: Verify the hemodynamic and autonomic responses to resistance exercise in elderly hypertensive women in use of medication, comparing traditional vs circuit-weight methods. METHODOLOGY: Ten elderly women (71,1 ± 5,5 years; 1,5 ± 0,1 m; 56,1 ± 9,8 kg; 24,2 ± 3,9 BMI) with controlled hypertension participated in the study. Volunteers were subjected to 4 familiarization and load determination sessions, and to 2 resistance exercise experimental sessions (traditional and circuit). Load was determined with the perceived exertion OMNI-RES scale, with the experimental protocol consisting in 3 series of 12 repetitions in 7 exercises. Blood pressure, heart rate variability (HRV) and blood pressure reactivity (Stroop color-word test) were evaluated before and after experimental sessions. A paired t-test was used for comparison of hemodynamic and autonomic variables at rest, and for further experimental sessions characteristics. Repeated analysis of variance were utilized to verify the effects of the 2 resistance exercise methods employed on blood pressure, HRV and blood pressure reactivity to mental stress. Significance level was set at p < 0.05. RESULTS: No changes on blood pressure were observed after exercise in any resistance exercise method employed, in relation to rest values. A vagal depression was observed during 15 minutes by frequency domain analysis of HRV, not confirmed by analysis in time domain. Heart rate complexity was reduced by 45 minutes post-exercise, with no difference between sessions. It was demonstrated, for the first time and similarly for both methods, that resistance exercise attenuated blood pressure reactivity to mental stress. This attenuation may be justified, in part, by an exercise-mediated reduction in sympathetic activation during stress. CONCLUSIONS: Resistance exercise is an effective tool to reduce blood pressure reactivity to mental stress, which could therefore be associated with an acute reduction on cardiovascular risk. This result presents relevant clinical implications, joining previous evidence that recommend this training modality as an important component of an exercise program designed for the elderly and hypertensive subjects.

In recent years, the interest in mental strain has increased, mainly due to the increasing demands of the individual professions. The consequences of mental strain can also influence private life, so it is important to solve such situation. The diploma thesis deals with the psychological burden of the employees in a private company that produces CNC machine parts. The aim was to find out what the level of mental strain on all employees of the company is, using the method of quantitative and qualitative research. Three research questions have been identified. I have examined whether the demographic factors of the worker, the physical factors in the working environment and the way of rest after work affect the psychological burden. The investigation was carried out using three hypotheses. I assumed that a significant level of psychological burden would be present in relation to the age and that it would also vary by gender. I also expected that the differences in the level of psychological burden would be present depending on the length of the years worked in the company. A qualitative survey was conducted using sixteen open questions in a semi-structured interview. The results were divided into eleven categories and there was a mind map created for each of them. For better understanding of the mind maps, the data was extended by quantitative questionnaire research, which was implemented using standardized CBI questionnaires (Copenhagen Burnout Inventory) and the Meister questionnaire. Questionnaire survey was carried out at each workplace of the surveyed company. The data were processed statistically and graphically. Mixed research has not shown a significant level of mental strain on company employees. When compared the ratio of mental strain in relation to gender, it has shown that the strain on both men and women is the same. The length of employment in the company has not reflected into increased rates of mental strain.

Mental disorders are now the most common disorders for sick leave benefit and the second most common for long periods of sick leave. They are also the most common reason for receiving disability pensions. Long term work-stress or burnout is a prevalent cause of mental disorders and since it’s causes could be clinical or societal, there is a need to systematically address it from different perspectives. The aim of this thesis is to construct an overarching model that encompasses more than the medical side to help local authorities develop a mental health strategy for work-stress mental health illnesses. The work-stress mental health situation in Stockholm is addressed using a systems mapping approach to visualize the effect of future strategies of relevant institutions. Literature is reviewed to understand the national context of mental health in Sweden, identify relevant actors which affect work stress mental health and highlight their roles. This is then presented in a systems map through which the impact of policies can be shown across sub-systems. It is presented to several experts for validation which results in agreement on the accuracy and relevance of the model, identification of more sub-systems, actors that can be added to the model and the limitations of important actors such as occupational health centres and primary care. The exercise also entailed insights on how national and local level mental health policies could factor in the individuals’ resources and support employers with wellness and rehabilitation to counteract stress at workplace. / Psykiska störningar är nu de vanligaste sjukdomarna för sjukfrånvaro och de näst vanligaste under långa sjukperioder. De är också det vanligaste skälet för att få invaliditetspension. Långvarig arbetstress eller utbrändhet är en vanlig orsak till psykiska störningar och eftersom orsakerna kan vara kliniska eller samhälleliga finns det ett behov av att systematiskt ta itu med det ur olika perspektiv. Syftet med denna avhandling är att konstruera en övergripande modell som omfattar mer än den medicinska sidan för att hjälpa lokala myndigheter att utveckla en mentalhälsostrategi för psykiska sjukdomar i arbetet. Arbetsstressens mentalhälsosituation i Stockholm behandlas med hjälp av en systemkartläggningsmetod för att visualisera effekten av framtida strategier för relevanta institutioner. Litteraturen granskas för att förstå den nationella kontexten för psykisk hälsa i Sverige, identifiera relevanta aktörer som påverkar arbetsstress mental hälsa och belyser deras roller. Detta presenteras sedan i en systemkarta genom vilken effekterna av policyer kan visas över delsystemen. Det presenteras för flera experter för validering som resulterar i en överenskommelse om modellens noggrannhet och relevans, identifiering av fler delsystem, aktörer som kan läggas till modellen och begränsningarna för viktiga aktörer som arbetshälsocentraler och primärvård . Övningen innehöll också insikter om hur psykisk hälsopolitik på nationell och lokal nivå skulle kunna påverka individens resurser och stödja arbetsgivare med wellness och rehabilitering för att motverka stress på arbetsplatsen.

Refugees who have fled from the ongoing civil war in Syria that arrived in Germany often develop post-traumatic stress symptoms (PTSS). The aim of this study was to determine health care services utilization (HCSU), health care costs and health-related quality of life (HrQoL) of Syrian refugees with mild to moderate PTSS without current treatment in Germany. The study was based on the baseline sample of a randomized controlled trial of a self-help app for Syrian refugees with PTSS (n = 133). HCSU and HrQoL based on the EQ-5D-5L and its visual analogue scale (EQ-VAS) were assessed with standardized interviews. Annual health care costs were calculated using extrapolated four-month HCSU and standardized unit costs. Associations between health care costs, HrQoL and PTSS severity were examined using generalized linear models. Overall, 85.0% of the sample utilized health care services within four months. The mean total annual health care costs were EUR 1920 per person. PTSS severity was not associated with health care costs. The EQ-5D-5L index score and the EQ-VAS score was 0.82 and 73.6, respectively. For Syrian refugees with higher PTSS severity, the EQ-5D-5L index score was lower (−0.17; p < 0.001). The HCSU and the resulting health care costs of Syrian refugees with mild to moderate PTSS without current treatment are low and those with a higher PTSS severity had a lower HrQoL.

Acute mental stress is an everyday phenomenon that has evidently intensified over the past decades and poses significant health risks. Conventional methods for stress assessment are not suitable for everyday use. They are suitable only for clinical and laboratory assessment because they require full attention, limit the freedom of movement (sensors, cables), often require trained personnel or special equipment, and thus are cost-intensive. This work investigates camera-based photoplethysmography (cbPPG), a non-contact technique for the monitoring of cardiovascular vital signs, as an alternative for the assessment of acute mental stress that is suitable for everyday use. As a non-contact technique cbPPG is considered susceptible to artifacts. To overcome limitations of existing cbPPG methods, this work covers essential developments for the robust extraction of non-contact vital signs in addition to the assessment of acute mental stress. An experimental study was designed and conducted with 65 healthy participants to gain a database for cbPPG including synchronized reference measurements (e.g. electrocardiography, skin conductance, salivary cortisol concentration). The experimental study resulted in the „Dresden Multimodal Biosignal Dataset for the Mannheim Multi-component Stress Test“ (DMBD). In addition, the „Binghamton-Pittsburgh-RPI Multimodal Spontaneous Emotion Database“ (BP4D+) was utilized. For robust extraction of non-contact vital signs measured with cbPPG, a novel method for the extraction of cbPPG signals was developed: O3C. O3C optimizes the combination of the color channels of RGB cameras with an evaluation metric in a specialized, systematic grid search. Several investigations on properties of the novel method revealed that the grid search always identified a global optimum. O3C was independent of different skin tones and the choice of evaluation metric. Temporal normalization of the RGB color channels improved the transferability of O3C between datasets (DMBD, BP4D+). At the example of breath rate measurement, it was shown that the method behind O3C is transferable from pulse rate to other vital signs. In addition, a novel method for automatic, reference-free identification of erroneous measurements was developed on the basis of signal quality indexes (SQIs). The developments on robust extraction of non-contact vital signs contribute to the fundamentals of cardiovascular monitoring that is suitable for everyday use. Among other aspects, this forms the basis for non-contact assessment of acute mental stress with cbPPG. In the experimental study (DMBD), conventional reference methods showed distinct changes in psychometric variables, chemical biomarkers, and contact-based vital signs during acute mental stress. The results are widely in line with existing literature and indicated successful activation of the hypothalamic-pituitary-adrenal axis (HPA axis) as well as sympathetic activation of the autonomic nervous system. A special characteristic of this investigation on stress assessment resides in the large variety of synchronized reference parameters, which allows a side-by-side comparison of the effectiveness of different measurement techniques. To assess the physiological reaction to acute mental stress with non-contact technique, ten vital signs derived with cbPPG were analyzed. The cbPPG vital signs registered positive chronotropy, peripheral vasoconstriction, and altered respiration in accordance with reference measurements. Thus, they also successfully indicated sympathetic activation of the autonomic nervous system. In a machine learning approach, the cbPPG vital signs were effective in detecting the immediate stress response with a fairly high temporal resolution of 30 s. These investigations are unique in terms of their extent and the possibility to adduce diverse synchronized reference measurements for comparison. They provide valuable insights into capabilities and effectiveness of cbPPG for non-contact assessment of acute mental stress. The findings of this work pave the way for robust non-contact monitoring with cbPPG. At the example of acute mental stress, a method for physiological assessment of the human state that is suitable for everyday use has been presented. This provides new opportunities to make use of the great potential that cbPPG offers for numerous everyday applications (e.g. telemedical video consultations, adaptive human-machine interfaces).:1 Introduction .. 1.1 Relevance .. 1.2 Scope .. 1.3 Outline .. 1.4 Delineation 2 Physiological Fundamentals .. 2.1 Stress and Strain .. .. 2.1.1 Historical Development .. .. 2.1.2 Definition .. 2.2 Endocrine System .. 2.3 Autonomic Nervous System .. 2.4 Cardiovascular System .. .. 2.4.1 Heart .. .. 2.4.2 Vascular System .. .. 2.4.3 Facial Vasculature .. 2.5 Skin 3 Methods to Assess the Human Response to Acute Mental Stress .. 3.1 Clinical and Laboratory Procedures .. .. 3.1.1 Stress Induction .. .. 3.1.2 Stress Response Assessment .. 3.2 Biomedical Engineering Techniques .. .. 3.2.1 Conventional Techniques .. .. .. 3.2.1.1 Electrocardiography .. .. .. 3.2.1.2 Photoplethysmography .. .. .. 3.2.1.3 Blood Pressure Measurement .. .. .. 3.2.1.4 Electrodermal Activity .. .. .. 3.2.1.5 Vital Signs of Conventional Techniques .. .. 3.2.2 Non-contact Techniques .. .. .. 3.2.2.1 Overview .. .. .. 3.2.2.2 Comparison .. 3.3 Summary 4 Camera-based Photoplethysmography .. 4.1 Functional Principle .. 4.2 Measurement Technology .. 4.3 Pulse Rate Measurement .. 4.4 Algorithms for Signal Extraction .. .. 4.4.1 Image Processing .. .. 4.4.2 Channel Combination .. .. 4.4.3 Signal Processing .. .. 4.4.4 Excursus: A Note on Deep Learning .. .. 4.4.5 Summary .. 4.5 Application to Stress Assessment 5 Study Design .. 5.1 Binghamton-Pittsburgh-RPI Multimodal Spontaneous Emotion Database .. 5.2 Dresden Multimodal Biosignal Dataset for the Mannheim Multicomponent Stress Test .. .. 5.2.1 Protocol .. .. 5.2.2 Setup .. .. 5.2.3 Annotations .. .. 5.2.4 Cohort Summary 6 Investigations on Robust Extraction of Non-contact Vital Signs .. 6.1 Color Space Transformations .. 6.2 Novel Method for the Optimization of Color Channel Combinations .. 6.3 Impact of Skin Tone on the Optimal Color Channel Combination .. 6.4 Impact of Normalization on the Optimal Color Channel Combination .. 6.5 Impact of Evaluation Metric on the Optimal Color Channel Combination .. 6.6 Optimal Color Channel Combination for Breath Rate Measurement .. 6.7 Signal Quality Index Filtering .. 6.8 Summary 7 Investigations on the Assessment of Acute Mental Stress .. 7.1 Examination of Reference Parameters .. 7.2 Examination of Camera-based Vital Signs .. 7.3 Prediction from Camera-based Vital Signs .. 7.4 Summary 8 Conclusion .. 8.1 Summary .. 8.2 Outlook References Appendix .. A Schematic Structure of the Autonomic Nervous System .. B Other Conventional Techniques for Biosignal Acquisition .. C Recording and Synchronization of the Dresden Multimodal Biosignal Dataset for the Mannheim Multicomponent Stress Test .. D Definition of Regions of Interest From Facial Landmarks .. E Definition of Color Space Transformations .. F Extended Results of Camera-based Pulse Rate Measurement With Different Color Spaces and Regions of Interest .. G Level-Set Regions of Interest in the Experimental Study .. H Relative Accuracy Differences Across the Hemispherical Surface Grid for Multiple Settings .. I Descriptive Statistics for the Reference Vital Signs of the Experimental Study .. J Insignificant Reference Vital Signs of the Experimental Study .. K Statistics for the Binary Logistic Regression with Forward Selection .. .. K.1 Omnibus Tests of Model Coefficients .. .. K.2 Model Summary .. .. K.3 Hosmer and Lemeshow Test .. .. K.4 Classification Table .. .. K.5 Equation Variables / Akuter mentaler Stress ist ein alltägliches Phänomen, dass sich im Laufe der vergangenen Jahrzehnte nachweislich intensiviert hat und ein Risiko für die Gesundheit darstellt. Herkömmliche Methoden zur Stressbewertung sind nicht alltagstauglich. Sie eignen sich nur für Klinik und Labor, da sie volle Aufmerksamkeit erfordern, Bewegungsfreiheit einschränken (Sensoren, Kabel), zumeist Fachpersonal oder Spezialausrüstung voraussetzen und entsprechend kostenintensiv sind. Diese Arbeit beschäftigt sich mit der kamerabasierten Photoplethysmographie (cbPPG), einer kontaktlosen Technik zum Monitoring kardiovaskulärer Vitalparameter, als alltagstaugliche Alternative zur Bewertung der physiologischen Reaktion auf akuten mentalen Stress. Als kontaktlose Technologie gilt cbPPG allerdings als artefaktanfällig. Um Limitationen bestehender Methoden zu überwinden, umfasst diese Arbeit neben der Stressbewertung mit cbPPG essenzielle Weiterentwicklungen zur robusten Extraktion kontaktloser Vitalparameter. Um eine Datenbasis für cbPPG mit zahlreichen Referenzmessverfahren (z. B. Elektrokardiografie, Hautleitfähigkeit, Speichelkortisolkonzentration) zu schaffen, wurde eine Experimentalstudie mit 65 gesunden Probanden aufgesetzt. Daraus resultierte das „Dresden Multimodal Biosignal Dataset for the Mannheim Multi-component Stress Test“ (DMBD). Zusätzlich fand die „Binghamton-Pittsburgh-RPI Multimodal Spontaneous Emotion Database“ (BP4D+) Anwendung. Für die robuste Extraktion von Vitalparametern mit cbPPG wurde eine neuartige Methodik zur Signalextraktion entwickelt: O3C. O3C optimiert die Kombination der Farbkanäle einer RGB-Kamera in einer spezialisierten, systematischen Rastersuche anhand einer Evaluationsmetrik. Die Untersuchung zentraler Eigenschaften von O3C zeigte, dass stets ein globales Optimum der Rastersuche existiert und die neue Methode robust gegenüber verschiedenen Hauttönen und Evaluationsmetriken ist. Zeitliche Normalisierung der RGB-Farbkanäle verbesserte die Übertragbarkeit von O3C zwischen verschiedenen Datensätzen (DMBD, BP4D+). Am Beispiel der Atemratenmessung wurde gezeigt, dass die Methodik von O3C auf andere Vitalparameter übertragbar ist. Darüber hinaus wurde eine neue Methode zur referenzfreien Identifikation fehlerhafter Messungen mittels Signalqualitätsindizes (SQIs) entwickelt. Die Entwicklungen zur robusten Extraktion von Vitalparametern leisten einen grundlegenden Beitrag für das alltagstaugliche kardiovaskuläre Monitoring mit cbPPG. Damit schaffen sie unter anderem die Voraussetzung für die kontaktlose Stressbewertung mit cbPPG. Die Referenzmessverfahren der Experimentalstudie (DMBD) zeigten bei akutem mentalem Stress deutliche Veränderungen psychometrischer Variablen, chemischer Biomarker und kontaktbasiert erfasster Vitalparameter. Die Ergebnisse stehen in weitreichender Übereinstimmung mit bisheriger Literatur und wiesen die erfolgreiche Aktivierung der Hypothalamus-Hypophysen-Nebennierenrinden-Achse und die sympathische Aktivierung des autonomen Nervensystems aus. Eine Besonderheit dieser Untersuchung zur Stressbewertung liegt in der Vielfalt synchronisierter Referenzparameter, mit der sich die Effektivität verschiedener Referenzmessverfahren direkt gegenüberstellen lässt. Für die kontaktlose Bewertung der physiologischen Reaktion auf akuten mentalen Stress wurden zehn cbPPG Vitalparameter analysiert. Die cbPPG Vitalparameter erfassten positive Chronotropie, periphere Vasokonstriktion und veränderte Atmung, und zeigten damit ebenfalls die sympathische Aktivierung des autonomen Nervensystems erfolgreich an. Die cbPPG Vitalparameter eigneten sich darüber hinaus zur zuverlässigen automatisierten Detektion der unmittelbaren Stressreaktion mit einer hohen zeitlichen Auflösung von 30 s. Die Untersuchungen sind einzigartig in ihrem Umfang und der Möglichkeit, diverse Referenzmessverfahren zum Vergleich heranzuziehen. Sie liefern damit wertvolle Erkenntnisse über Möglichkeiten und Leistungsfähigkeit von cbPPG zur kontaktlosen Stressbewertung. Die Ergebnisse dieser Arbeit ebnen den Weg für ein robustes kontaktloses Monitoring mittels cbPPG. Am Beispiel akuten mentalen Stresses wurde eine Methode zur alltagstauglichen Bewertung physiologischer Zustände aufgezeigt. Damit eröffnen sich neue Möglichkeiten, das große Potenzial von cbPPG für zahlreiche Anwendungsfälle (z. B. adaptive Mensch-Maschine-Schnittstellen, telemedizinische Videokonsultationen) alltagstauglich zu erschließen.:1 Introduction .. 1.1 Relevance .. 1.2 Scope .. 1.3 Outline .. 1.4 Delineation 2 Physiological Fundamentals .. 2.1 Stress and Strain .. .. 2.1.1 Historical Development .. .. 2.1.2 Definition .. 2.2 Endocrine System .. 2.3 Autonomic Nervous System .. 2.4 Cardiovascular System .. .. 2.4.1 Heart .. .. 2.4.2 Vascular System .. .. 2.4.3 Facial Vasculature .. 2.5 Skin 3 Methods to Assess the Human Response to Acute Mental Stress .. 3.1 Clinical and Laboratory Procedures .. .. 3.1.1 Stress Induction .. .. 3.1.2 Stress Response Assessment .. 3.2 Biomedical Engineering Techniques .. .. 3.2.1 Conventional Techniques .. .. .. 3.2.1.1 Electrocardiography .. .. .. 3.2.1.2 Photoplethysmography .. .. .. 3.2.1.3 Blood Pressure Measurement .. .. .. 3.2.1.4 Electrodermal Activity .. .. .. 3.2.1.5 Vital Signs of Conventional Techniques .. .. 3.2.2 Non-contact Techniques .. .. .. 3.2.2.1 Overview .. .. .. 3.2.2.2 Comparison .. 3.3 Summary 4 Camera-based Photoplethysmography .. 4.1 Functional Principle .. 4.2 Measurement Technology .. 4.3 Pulse Rate Measurement .. 4.4 Algorithms for Signal Extraction .. .. 4.4.1 Image Processing .. .. 4.4.2 Channel Combination .. .. 4.4.3 Signal Processing .. .. 4.4.4 Excursus: A Note on Deep Learning .. .. 4.4.5 Summary .. 4.5 Application to Stress Assessment 5 Study Design .. 5.1 Binghamton-Pittsburgh-RPI Multimodal Spontaneous Emotion Database .. 5.2 Dresden Multimodal Biosignal Dataset for the Mannheim Multicomponent Stress Test .. .. 5.2.1 Protocol .. .. 5.2.2 Setup .. .. 5.2.3 Annotations .. .. 5.2.4 Cohort Summary 6 Investigations on Robust Extraction of Non-contact Vital Signs .. 6.1 Color Space Transformations .. 6.2 Novel Method for the Optimization of Color Channel Combinations .. 6.3 Impact of Skin Tone on the Optimal Color Channel Combination .. 6.4 Impact of Normalization on the Optimal Color Channel Combination .. 6.5 Impact of Evaluation Metric on the Optimal Color Channel Combination .. 6.6 Optimal Color Channel Combination for Breath Rate Measurement .. 6.7 Signal Quality Index Filtering .. 6.8 Summary 7 Investigations on the Assessment of Acute Mental Stress .. 7.1 Examination of Reference Parameters .. 7.2 Examination of Camera-based Vital Signs .. 7.3 Prediction from Camera-based Vital Signs .. 7.4 Summary 8 Conclusion .. 8.1 Summary .. 8.2 Outlook References Appendix .. A Schematic Structure of the Autonomic Nervous System .. B Other Conventional Techniques for Biosignal Acquisition .. C Recording and Synchronization of the Dresden Multimodal Biosignal Dataset for the Mannheim Multicomponent Stress Test .. D Definition of Regions of Interest From Facial Landmarks .. E Definition of Color Space Transformations .. F Extended Results of Camera-based Pulse Rate Measurement With Different Color Spaces and Regions of Interest .. G Level-Set Regions of Interest in the Experimental Study .. H Relative Accuracy Differences Across the Hemispherical Surface Grid for Multiple Settings .. I Descriptive Statistics for the Reference Vital Signs of the Experimental Study .. J Insignificant Reference Vital Signs of the Experimental Study .. K Statistics for the Binary Logistic Regression with Forward Selection .. .. K.1 Omnibus Tests of Model Coefficients .. .. K.2 Model Summary .. .. K.3 Hosmer and Lemeshow Test .. .. K.4 Classification Table .. .. K.5 Equation Variables