Automated detection of obstructive apnea and hypopnea events from oxygen saturation signal

Abstract

Our objective is to automate the detection of apnea and hypopnea events in obstructive sleep apnea hypopnea (OSAH) syndrome based on analysis of arterial oxygen saturation signal alone. This is the first attempt where wavelet is used to detect OSAH events. Detection of OSAH events through wavelet depends on the fluctuations in the magnitude of the transformed coefficients, thus circumventing the problem of variability in the criteria on the magnitude and duration of the signal. Our work evaluates the performance of the wavelet transform to detect OSAH events against three conventional amplitude and duration algorithms. High performance in the detection of OSAH events can be achieved through the wavelet algorithm (score 96.55%, sensitivity 95.74% and specificity 97.02%) if the threshold on wavelet coefficients is individually tuned for each study. However, this is impossible in clinical practice. It is interesting to observe that the conventional methods based on amplitude and duration are able to attain a performance as close as this. The Nervus algorithm obtains the best result (score 96.66%, sensitivity 95.26% and specificity 97.46%) compared to the amplitude duration algorithm, the drop duration algorithm and the wavelet algorithm with global threshold, in descending order of performance.

Assessment of computerized analysis algorithms for one dimension physiologic data with multiple databases

“…Several issues contributing to this are suggested and publications pertaining to this are invited. It is a surprise that our research into the computerized analysis of oxygen saturation to detect for desaturation events [2][3] reveals supportive evidence to issues raised in [1].…”

Multiresolution wavelet analysis for efficient analysis, compression and remote display of long-term physiological signals

“…Desaturation events in Sp02: Oximetry is one of the simpler and cheaper alternatives to polysomnograph for diagnosing obstructive sleep apnoea (OSA) 19 . MrWA is shown to be capable of detecting both the deep and fluctuating desaturation patterns in oxygen saturation, which define abnormal oximetry 20 .…”

A System for the Analysis of Snore Signals

“…Current methods alternative to PSG are: overnight oximetry, which measures a patient's oxygen saturations throughout the night [6], ECG [7] or snore monitoring [8]. Overnight oximetry is not considered completely adequate as a screening test, since the oxygen levels in the blood of many patients with SAS do not provide the information needed to understand their condition.…”