Detection of airway obstruction and sleep apnea by analyzing the phase relation of respiration movement signals

The authors introduce a novel diagnostic method of a sleep disorder, sleep apnea syndrome (SAS), which may cause numerous irreversible complications with severe consequences without treatment. The sleep laboratory test called polysomnography is the main aid to the experts to recognize and obtain the grade of SAS. A polysomnographic record consists of several channels such as nasal air flow, blood pressure, abdominal and thoracic excursion, blood oxygen saturation etc. Several well-known methods exist to analyze one or more of these signals. We present a method, which uses the phase relation information between the abdominal and thoracic respiration movements in order to detect the grade and type of SAS