OSAS detection in children by using PPG amplitude fluctuation decreases and pulse rate variability

An analysis of the pulse rate variability (PRV) during decreases in the amplitude fluctuations of pulse photoplethysmographic (PPG) signal (DAP) events, and their utility in obstructive sleep apnea syndrome (OSAS) screening is presented as an alternative to heart rate variability (HRV) which will save the need of electrocardiogram (ECG) recording. 21 polysomnographic registers from children whose age was 4.47 ± 2.04 (mean ± SD) years were manually labeled as OSAS (10 children) or not (11 children) following standard clinical procedures. Then DAP events were automatically detected and classified as apneic or non apneic by a linear discriminant analysis whose features come from the PRV. Subsequently, the apneic DAP event per hour index was used to discriminate OSAS from non-OSAS children. Results show an improvement in accuracy of subject classification with respect to the HRV analysis of 6.7%, reaching a 86.7% (100% for sensitivity and 71.4% for specificity). These results suggest that PRV can be used to discriminate apneic and non-apneic DAP events without introducing any additional signal and so a decision from just the PPG with same results as if the ECG were also considered, which takes special relevance in sleep studies.