A method of characterizing a patient's disordered breathing during a sleeping period, comprising: receiving at least a first signal that is representative of the sounds occurring during at least a portion of the sleeping period in the vicinity of the patient; identifying in the at least first signal a plurality of segments by: subjecting at least a portion of the at least first signal to a linear prediction algorithm to obtain an excitation signal that is representative of the at least portion of the at least first signal, identifying as a plurality of candidate transition points in the excitation signal a plurality of simultaneous occurrences of a low energy level and a rapid change in the excitation signal between a negative slope and a positive slope, determining that a plurality of portions of the excitation signal that exist between pairs of candidate transition points are similar to one another based at least in part upon similarity of the period and the spectral content of the plurality of portions, and based at least in part upon the determining, concluding that the pairs of candidate transition points are actual transition points, a portion of the excitation signal that immediately precedes each actual transition point is an inhalation phase of a breathing cycle, and a portion of the excitation signal that immediately follows each actual transition point is an exhalation phase of a breathing cycle; and generating an output that comprises information that is based at least in part upon at least one of the inhalation phases and the exhalation phases. receiving at least a first signal that is representative of the sounds occurring during at least a portion of the sleeping period in the vicinity of the patient; identifying in the at least first signal a plurality of segments by: subjecting at least a portion of the at least first signal to a linear prediction algorithm to obtain an excitation signal that is representative of the at least portion of the at least first signal, identifying as a plurality of candidate transition points in the excitation signal a plurality of simultaneous occurrences of a low energy level and a rapid change in the excitation signal between a negative slope and a positive slope, determining that a plurality of portions of the excitation signal that exist between pairs of candidate transition points are similar to one another based at least in part upon similarity of the period and the spectral content of the plurality of portions, and based at least in part upon the determining, concluding that the pairs of candidate transition points are actual transition points, a portion of the excitation signal that immediately precedes each actual transition point is an inhalation phase of a breathing cycle, and a portion of the excitation signal that immediately follows each actual transition point is an exhalation phase of a breathing cycle; and subjecting at least a portion of the at least first signal to a linear prediction algorithm to obtain an excitation signal that is representative of the at least portion of the at least first signal, identifying as a plurality of candidate transition points in the excitation signal a plurality of simultaneous occurrences of a low energy level and a rapid change in the excitation signal between a negative slope and a positive slope, determining that a plurality of portions of the excitation signal that exist between pairs of candidate transition points are similar to one another based at least in part upon similarity of the period and the spectral content of the plurality of portions, and based at least in part upon the determining, concluding that the pairs of candidate transition points are actual transition points, a portion of the excitation signal that immediately precedes each actual transition point is an inhalation phase of a breathing cycle, and a portion of the excitation signal that immediately follows each actual transition point is an exhalation phase of a breathing cycle; and the pairs of candidate transition points are actual transition points, a portion of the excitation signal that immediately precedes each actual transition point is an inhalation phase of a breathing cycle, and a portion of the excitation signal that immediately follows each actual transition point is an exhalation phase of a breathing cycle; and generating an output that comprises information that is based at least in part upon at least one of the inhalation phases and the exhalation phases.