A system and method for determining respiratory cycle-related EEG changes (RCREC) for a subject with sleep-disordered breathing are provided. The method includes receiving an EEG signal from the subject using at least one sensor, and defining at least two respiratory cycle segments within each respiratory cycle. The method further includes determining an EEG power of the EEG signal during each of the at least two respiratory cycle segments, and determining RCREC by calculating a difference between a maximum EEG segment power and a minimum EEG segment power.