Patent ID: 8403848

Claim:
A method of evaluating a subject's sleep quality, comprising: accessing a first series of physiological data representing respiration data of the subject; accessing a second series of physiological data representing cardiac data of the subject, said second series being, temporally aligned with said first series; calculating a data series of coherent cross power based on the first and second series by determining a cross-spectra power and a coherence for each of a plurality of temporally aligned subsets of data from said first series and said second series and computing said coherent cross power for each temporally aligned subset, said coherent cross power being computed from the product of said cross-spectra power and said coherence of each temporally aligned subset; determining cardiopulmonary coupling from the data series of coherent cross power; and comparing the cardiopulmonary coupling to a detection threshold associated with sleep quality, wherein the method is executed in a processor of a computer system.