Sleep apnea syndrome testing apparatus, test method for sleep apnea syndrome and tangible recording medium recording program

摘要

A sleep apnea syndrome testing apparatus includes: an analyzing unit that analyzes every unit time a sound signal resulting from a subject during sleep; a determining unit that determines whether a unit time of the sound signal includes a breath sound or a characteristic sound produced when a patient with sleep apnea syndrome recovers from an apneic state into a breathing state, and the determining unit that determines that the sleep state of the subject in the unit time is any one of “breathing restored state,” “state with breathing,” and “state without breathing;” a storage unit in which a sleep state of the subject in each unit time is stored; and a detecting unit that detects an apneic state of the subject if a history of the sleep states of the subject indicates at least a transition from the “state without breathing” to the “breathing restored state.”

主权项

1. A sleep apnea syndrome testing apparatus comprising:
an analyzing unit configured to analyze a sound signal resulting from a subject during sleep and collected by a sound pickup device; and to calculate frequency characteristics of a partial sound signal being a sound produced by the subject and being included in the sound signal; and a determining unit configured to:
calculate, based on the calculated frequency characteristics, duration of the partial sound signal;determine whether or not the duration and the frequency characteristics of the partial sound signal match a characteristic sound; anddetermine whether or not the sound signal includes a characteristic sound produced when a sleep state of the subject recovers from an apneic state into a breathing state, wherein the analyzing unit is configured to divide the sound signal in a unit of time into M time intervals by a predetermined time interval length, wherein M is a natural number not including zero, and calculate a power spectrum in each time interval, and wherein the determining unit is configured to calculate the duration of the partial sound signal by:
calculating a correlation coefficient between a power spectrum of a sound signal in a time interval T, wherein T is greater than or equal to zero and less than or equal to M−1, and a power spectrum of a sound signal in a time interval (T-t), wherein t is a positive integer;comparing the correlation coefficient with a threshold value;when the correlation coefficient is greater than the threshold value, detecting a sound signal continuing from the time interval (T-t) to the time interval T; increasing a value of the t by one; and repeating the calculation of the correlation coefficient,wherein, when the t is equal to or greater than two, the determining unit performs the calculation of the correlation coefficient regarding the time the time interval T and the time interval (T-t) which are not adjacent;repeating the calculation of the correlation coefficient until the correlation coefficient is smaller than the threshold value; andcalculating duration of the sound signal based on the detection of the sound signal continuing from time interval (T-t) to the time interval T.