Elicitation techniques for the evaluation of speech under stress: Towards a framework for use in a controlled environment

Existing work in Computer Science and Electronic Engineering demonstrates that Digital Signal Processing techniques can effectively identify the presence of stress in the speech signal. These techniques use datasets containing real or actual stress samples i.e. real-life stress such as 911 calls and so on. Studies that use simulated or laboratory-induced stress have been less successful and inconsistent. Pervasive, ubiquitous computing is increasingly moving towards voice-activated and voice-controlled systems and devices. Speech recognition and speaker identification algorithms will have to improve and take emotional speech into account. Modelling the influence of stress on speech and voice is of interest to researchers from many different disciplines including security, telecommunications, psychology, speech science, forensics and Human Computer Interaction (HCI). The aim of this work is to assess the impact of moderate stress on the speech signal. In order to do this, a dataset of laboratory-induced stress is required. While attempting to build this dataset it became apparent that reliably inducing measurable stress in a controlled environment, when speech is a requirement, is a challenging task. This work focuses on the use of a variety of stressors to elicit a stress response during tasks that involve speech content. Biosignal analysis (commercial Brain Computer Interfaces, eye tracking and skin resistance) is used to verify and quantify the stress response, if any. This thesis explains the basis of the author’s hypotheses on the elicitation of affectively-toned speech and presents the results of several studies carried out throughout the PhD research period. These results show that the elicitation of stress, particularly the induction of affectively-toned speech, is not a simple matter and that many modulating factors influence the stress response process. A model is proposed to reflect the author’s hypothesis on the emotional response pathways relating to the elicitation of stress with a required speech content. Finally the author provides guidelines and recommendations for future research on speech under stress. Further research paths are identified and a roadmap for future research in this area is defined.

Gene × environment interactions in schizophrenia: evidence from genetic mouse models

The study of gene × environment, as well as epistatic interactions in schizophrenia, has provided important insight into the complex etiopathologic basis of schizophrenia. It has also increased our understanding of the role of susceptibility genes in the disorder and is an important consideration as we seek to translate genetic advances into novel antipsychotic treatment targets. This review summarises data arising from research involving the modelling of gene × environment interactions in schizophrenia using preclinical genetic models. Evidence for synergistic effects on the expression of schizophrenia-relevant endophenotypes will be discussed. It is proposed that valid and multifactorial preclinical models are important tools for identifying critical areas, as well as underlying mechanisms, of convergence of genetic and environmental risk factors, and their interaction in schizophrenia.

Management of safety climate and the psychosocial work environment – new challenges for occupational health and safety professionals?

Introduction: The work environment and Occupational Health and Safety (OHS) practice have changed over the last number of years. A holistic OHS approach has been recommended by the authorities in this field (e.g. World Health Organisation (WHO), European Agency for Safety and Health at Work (EU-OSHA) and the International Labour Organisation (ILO)). This involves a unified action engaging elements of the physical and psychosocial workplace with greater focus on prevention and promotion of health and wellbeing. The health and safety practitioner (HSP) has been recognised as one of the main agents for implementation of OHS. Within an organisation they act as a leader of change and a professional who shapes health and safety while safeguarding the wellbeing of individuals at work. Additionally, safety climate (SC) has been developed as an essential concept for OHS of an organisation, its productivity and the wellbeing of its workforce. Scholars and practitioners have recognised the great need for further empirical evidence on the HSP’s role in a changing work environment that increasingly requires the use of preventative measures and the assessment and management of psychosocial work-related risks. This doctoral research brings together the different concepts used in OHS and Public Health including SC, Psychosocial workplace risks, Health Promotion and OHS performance. The associations between these concepts are analysed bearing in mind the WHO Healthy Workplace Framework and three of its main components (physical and psychosocial work environment and health resources). This thesis aims to establish a deeper understanding of the practice and management of OHS in Ireland and the UK, exploring the role of HSPs (employed in diverse sectors of activity) and of SC in the OHS of organisations. Methods: One systematic review and three cross-sectional research studies were performed. The systematic review focussed on the evidence compiled for the association of SC with accidents and injuries at work, clarifying this concept’s definition and its most relevant dimensions. The second article (chapter 3) explored the association of SC with accidents and injuries in a sample of workers (n=367) from a pharmaceutical industry and compared permanent with non-permanent workers. Associations of safety climate with employment status and with self-reported occupational accidents/injuries were studied through logistic regression modelling. The third and fourth papers in this thesis investigated the main tasks performed by HSPs, their perceptions of SC, health climate (HC), psychosocial risk factors and health outcomes as well as work efficacy. Validated questionnaires were applied to a sample of HSPs in Ireland and UK, members of the Institute of Occupational Safety and Health (n=1444). Chi-square analysis and logistic regression were used to assess the association between HSPs work characteristics and their involvement in the management of Psychosocial Risk Factors, Safety Culture and Health Promotion (paper 3). Multiple linear regression analysis was used to determine the association between SC, HC, psychosocial risk factors and health outcomes (general health and mental wellbeing) and self-efficacy. Results: As shown in the systematic review, scientific evidence is unable to establish the widely assumed causal link between SC and accidents and injuries. Nevertheless, the current results suggested that, particularly, the organisational dimensions of SC were associated with accidents and injuries and that SC is linked to health, wellbeing and safety performance in the organisation. According to the present research, contingent workers had lower SC perceptions but showed a lower accident/injury rate than their permanent colleagues. The associations of safety climate with accidents/injuries had opposite directions for the two types of workers as for permanent employees it showed an inverse relationship while for temporary workers, although not significant, a positive association was found. This thesis’ findings showed that HSPs are, to a very small degree, included in activities related to psychosocial risk management and assessment, to a moderate degree, involved in HP activities and, to a large degree, engaged in the management of safety culture in organisations. In the final research study, SC and HC were linked to job demands-control-support (JDCS), health, wellbeing and efficacy. JDCS were also associated with all three outcomes under study. Results also showed the contribution of psychosocial risk factors to the association of SC and HC with all the studied outcomes. These associations had rarely been recorded previously. Discussion & Conclusions: Health and safety climate showed a significant association with health, wellbeing and efficacy - a relationship which affects working conditions and the health and wellbeing of the workforce. This demonstrates the link of both SC and HC with the OHS and the general strength or viability of organisations. A division was noticed between the area of “health” and “safety” in the workplace and in the approach to the physical and psychosocial work environment. These findings highlighted the current challenge in ensuring a holistic and multidisciplinary approach for prevention of hazards and for an integrated OHS management. HSPs have shown to be a pivotal agent in the shaping and development of OHS in organisations. However, as observed in this thesis, the role of these professionals is still far from the recommended involvement in the management of psychosocial risk factors and could have a more complete engagement in other areas of OHS such as health promotion. Additionally, a strong culture of health and safety with supportive management and buy-in from all stakeholders is essential to achieve the ideal unified and prevention-focussed approach to OHS as recommended by the WHO, EU-OSHA and ILO.