A method of a device detects a respiratory effort-related arousal in a respiratory airflow signal of a patient. The method may include computing a measure of consistency of inspiratory flow limitation over a plurality of recent breaths from the signal. The method may further include computing a measure of step change in ventilation indicating a sudden big breath. The method may further include computing a measure indicating a degree of confidence of occurrence of a respiratory effort-related arousal from the measure of consistency of inspiratory flow limitation and the measure of the step change in ventilation.
