Abstract: A method (an corresponding system) of processing recordings of a subject's breathing, the method comprising: obtaining a tracheal recording of the subject's breathing; dividing the tracheal recording into a plurality of segments, and, for each segment of the plurality of segments: computing energy of the tracheal recording of the segment; computing power spectral density of the tracheal recording of the segment; processing the computed power spectral density to form a set of poles for the segment; iterating through the set of poles from a lowest frequency to a highest frequency to produce a set of pitches for the segment by discarding all poles outside a defined range around 1.0, and upon finding a pole having a magnitude within a defined range around 1.