Vakgroep Menselijke fysiologie (MFYS)

Periodic breathing (PB) is a form of sleep-disordered breathing (SDB) characterized by instability in the respiratory pattern that shows an oscillatory behavior. PB is correlated with higher levels of mortality and can be found, e.g., in subjects with damaged respiratory centers, who are exposed to acute hypoxia or suffering from chronic heart failure.
To further explore PB, we conducted an experiment at the Concordia station in the framework of the European Space Agency’s Life Science campaign. In this experiment, that took part during the 2012 winter over, 13 healthy male participants were monitored using a wireless polysomnography. Because of its altitude, at approximately 3800 meters, Concordia provides a unique environment for the study of PB. This is to our knowledge the longest duration study about adaptation to hypoxia ever done. Therefore, the results from this study will provide new insights on the evolution of PB over time.
The standard measure for the diagnosis of sleep-related breathing disorders is the apnea/hypopnea index (AHI), which measures the proportion of apneic/hypopneic events during polysomnography. This measure just provides quantitative information regarding PB, instead of qualitative. Furthermore, Determining the AHI is labor-intensive, requires the simultaneous recording of four signals and visual checks by an expert scorer.  We are studying further other solutions for quantify PB in a qualitative, automated and simple way based on signal processing tools.
Mathematical models for studying PB are very important for understanding the process originating it. Most of the actual models assume a linear feedback control between central and peripheral chemoreceptors. Some recent studies may suggest that the feedback between chemoreceptors might rather be nonlinear.  In our research, we will further analyze if feedbacks that are more complex can better explain PB.
The multidisciplinary character of this project requires on the one hand an advance knowledge in human physiology, and on the other hand, expertise in signal processing and system modeling. Therefore, this PhD requires both the guidance and expertise from both worlds, engineering and life sciences. The part of the needed expertise in human physiology required for this research proposal is being provided by Prof. Dr. Meeusen Romain from the Faculty of Physical Education and Physical Therapy, Movement and Sports Training at the VUB. For the signal processing and system modeling knowledge, we are being guided by the expertise of Prof. Dr. Xavier Neyt, associate professor at the Communication, Information, Systems and Sensors department of the Royal Military Academy.