A method for monitoring the variations in the upper airway of individual OSAHS patients by observing two acoustic feature tracks

Monitoring the variations in the upper airway (UA) for individual Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS) patients by utilizing acoustic signal analysis methods is significant to research and develop convenient equipment to overcome the invasive airway pressure measurements. It is noticeable that acoustic features like formant frequencies and power ratios had achieved good results both on diagnosing OSAHS and revealing the relationship between properties and anatomical structure. We adopted the first formant frequency (F1) and power ratio at frequency of 800 Hz (PR800) as target values to observe the tracks of them in snore episodes before an apnea/hypopnea event, which could help doctors to know the structure variations in UA for OSAHS patients. Results showed that the tracks of the two acoustic features have a good performance on demonstrating the reasonable theoretical hypothesis. If we get enough prior knowledge by large scale of experiments and practices, we can even use the tracks of F1 and PR800 to find some more detailed information of UA like observing the electrocardiogram in cardiac healthcare and monitoring.