I feel terrible! Can you measure that? : Exploring psychophysiological stress responses and their interactions with performance, subjective reports and health status

Despite recent research advances, there are still several common medical conditions whose underlying mechanisms are poorly understood. In conditions with few or diffuse physical findings, it can be difficult to diagnose and determine the state of the condition and its effects on working ability or performance, and the health care practitioners have to rely on the patient’s self-reports. Identification of objective measurements that are sensitive enough to aid in diagnosis or determination of the state of these conditions would thus be valuable. Psychophysiological measurements are generally non-invasive and have the potential to serve as such diagnostic or prognostic tools. In this thesis, psychophysiological reactions to different stressors were recorded in two selected medical conditions; namely motion sickness and chronic trapezius myalgia (musculoskeletal pain). These subjective conditions are unpleasant, unwanted and apparently serve no survival purpose. It is therefore important to elucidate any physical findings associated with them to, eventually, find new means to prevent the development of these conditions or to ameliorate symptoms. The overall aim of the thesis was to explore the development of psychophysiological responses to stressors in relation to performance and subjective reports in healthy individuals and in women with chronic trapezius myalgia. More in detail, the purpose was to identify psychophysiological responses that could provide information about the mechanisms behind, or serve as candidates for characterization of motion sickness and chronic trapezius myalgia, respectively. Responses to motion sickness, triggered by optokinetic stimulation, were studied in healthy individuals, whereas responses to repetitive low-force work and psychosocial stress were studied in women with chronic trapezius myalgia and in pain-free controls. In both medical conditions, the psychophysiological responses were accompanied by subjective reports. The effects of