In patients with sleep related breathing disorders parallel evaluation of respiration, blood gases and the EEG are indispensible. Computerized methods can provide a detailed analysis of the interrelation of these parameters to enlighten the disturbed central regulation of respiration in these patients. These methods also can help to achieve a better differential diagnosis in routine clinical work. A new method is presented here which evaluates the signals of nasal airflow, thoracic and abdominal movements together with oxygen saturation and heart rate in parallel. The new method is validated using a detailed visual analysis. Results prove the usefulness of the new method. To apply the method the relationship between length of apnea and oxygen desaturation is evaluated for different sleep stages separately.