Blunted Autonomic Reactivity to Mental Stress in Depression Quantified by Nonlinear Cardiorespiratory Coupling Indices

Spyridon Kontaxis1, Pablo Laguna2, Esther García Pages3, Mar Posadas-de Miguel4, Sara Siddi5, Maria Luisa Bernal6, Josep Maria Haro7, Jordi Aguiló3, Concepción de la Camara6, Raquel Bailón8, Eduardo Gil9
1Biomedical Research Networking Centre on Bioengineering, Biomaterials and Nanomedicine, 2Zaragoza University, 3CIBER de Bioingeniería, Biomateriales y Nanomedicina, Spain, Microelectronics and Electronic Systems Dept., Autonomous University of Barcelona, Spain, 4Instituto de Investigacíon Sanitaria de Aragón (IIS Arag´on), Zaragoza, Spain, 5CIBER de Salud Mental, Spain, 6Instituto de Investigación Sanitaria de Aragón (IIS Aragón), Zaragoza, Spain, 7CIBER de Salud Mental, Spain, Parc Sanitari Sant Joan de D´eu, Sant Boi de Llobregat, Barcelona, Spain, 8I3A, IIS, Universidad de Zaragoza, CIBER-BBN, 9University of Zaragoza


In this study, differences in autonomic reactivity to men- tal stress between Major Depressive Disorder (MDD) pa- tients and healthy control (HC) subjects are assessed by nonlinear cardiorespiratory coupling indices derived from the Real Wavelet Biphase. The degree and strength of Quadratic Phase Coupling (QPC) between interacting os- cillations of Heart Rate Variability (HRV) and respiration are quantified before, during and after the execution of a cognitive task. Results show that the QPC strength and QPC degree between the respiration and the respiratory si- nus arrhythmia component of HRV were lower in HC com- pared to MDD during stress, suggesting that the parasym- pathetic branch was less inhibited in MDD patients. Dur- ing recovery, only in HC group, this degree of QPC in- creased, while the respiratory rate was reduced, compared to the basal stage. The degree of QPC between the respi- ration and components of HRV in the low frequency band ([0.04, 0.15] Hz) increased in HC during stress, compared to the basal stage, while remained unchanged in MDD pa- tients. These results imply that depression is associated with blunted autonomic reactivity to mental stress.