Measurement of acute psychological stress /
- Autores: Adriana Arza Valdés
- Directores de la Tesis: Jordi Aguiló Llobet (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: María Teresa Arredondo Waldmeyer (presid.), Theodora Tsapikouni (secret.), Driss Moussaoui (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Microelectrónica y Sistemas Electrónicos
- Materias:
- Enlaces
- Resumen
The incidents of anxiety, depression, epilepsy, multiple sclerosis, pathological stress, as well as other different stress related diseases have significantly increased in recent years and it is most probably due to dramatic changes in the daily lifestyle of citizens. The social and medical problems associated to stress are clearly on the rise and seriously affecting mental health and wellbeing not only in adults but also in young adults and children, according to the WHO (World Health Organization). There is currently an increased awareness of stress, specifically with regards to its medical, social and economic importance; and also, because there are several stress-related comorbidities that remain largely understudied. Therefore, stress has become one of the significant focal points of research interest. Despite the efforts made, a scientifically supported, repeatable and usable in daily life measurement method of stress is still not available. An objective and reliable measurement of stress level could be used to compare the level of stress’ severity in different individuals or between different sets of professionals. It would also be a crucial tool for the prevention, diagnosis and treatment of several diseases.
Stress can be defined as the disturbance of the homeostatic balance when facing a specific threat to the body (a stressor) that provokes a stress response. The stress response is the body’s attempt to deal with the stressor triggering the different reactions that can be broadly summarised as changes in the autonomous nervous system, a hormonal response (adrenal pituitary adrenal axis) and a behavioural change and/or a decrease in cognitive skills. The methods that have been proposed until now for measuring the different aspects of stress considering its multidimensional quality, can be gathered in three groups: psychometric tests, biochemical markers, and physiological markers. Although biochemical samples and psychometric questionnaires are commonly used stress markers, they do not allow continuous or even regular stress assessment. Therefore, the hypothesis of this PhD thesis is that the stress response level due to a psychological stressor can be determined from a set of physiological parameters, which can be noninvasively and continuously measured. Consequently, the methodology and analysis of results presented are focused on objectively quantifying the physiological component of the stress response level, which can be understood as how close or far an individual is from his/her state of homeostatic balance.
To this end, an experimental study was developed to quantify acute psychological stress in healthy young people using biomarkers from physiological signals, which can be continuously and noninvasively measured. An acute stress response was induced to 40 volunteers by applying a modification of the Trier Social Stress Test (TSST), a widely used and documented protocol for lab-induced stress. Standard psychological tests and biochemical stress markers were used as references for stress levels. A multivariable approach to stress measurement is proposed, which includes as stress biomarkers features derived from finger and face temperature, heart rate variability and pulse photoplethysmogram. The results obtained show that, under the given conditions, stress can be assessed and measured quantitatively and continuously from noninvasive biomarkers, as continuous stress measurement was performed every 1 minute. Based on this approach, a stress monitoring method could emerge in the near future.
Finally, based on the findings from the experimental study and literature review presented in this thesis, a set of guidelines for the development of a stress measurement system were suggested to delineate the specifications for a stress monitoring system in daily life conditions. Also, some key considerations and challenges of this emerging area of study are addressed.
