In Japan, the number of latent patients of OSAHS (obstructive sleep apnea-hypopnea syndrome) is more than two million. But, only 20% of this number has undergone medical examination for OSAHS. Also, the inspection methods employed are polysomnography and simple polygraphy, which involve several sensors and electrodes and hence cause considerable inconvenience to the patient. To address this issue, in this study, we developed a throat sound measurement system. This system has a contact-type microphone attached to the neck and measures the sound at the time of breath (throat sound). I have already demonstrated that throat sounds are closely correlated with nasal airflow. In this study, I detected apnea-hypopnea using the developed throat sound measurement system. I formulated three methods of automatic detection and termed them "Time Interval of Peaks," "Moving Average," and "Binary Digit." I determined the detection rate and undetection rate of these methods. Six healthy subjects participated in this study. In addition, I examined whether this system automatically detected Apnea-Hypopnea of OSAHS. The analysis results for the healthy subjects showed the combined detection rate of the methods to be 100%. The undetection rates of "Time Interval of Peaks," "Moving Average," and "Binary Digit" were 8.6%, 14.5%, and 10.2%, respectively. Further, with regard to the OSAHS analysis, the combined detection rate of the methods was 100%. The undetection rates of "Time Interval of Peaks" and "Binary Digit" were both 0%. The undetection rate of "Moving Average" was 9.1%. Based on the above-mentioned results, I believe that the developed system is effective in OSAHS detection.
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