J Korean Med Sci.  2017 Jun;32(6):893-899. 10.3346/jkms.2017.32.6.893.

Obstructive Sleep Apnea Screening Using a Piezo-Electric Sensor

• Erdenebayar U
• Park JU
• Jeong P
• Lee KJ

• KMID: 2377717
• DOI: http://doi.org/10.3346/jkms.2017.32.6.893

Abstract

In this study, we propose a novel method for obstructive sleep apnea (OSA) detection using a piezo-electric sensor. OSA is a relatively common sleep disorder. However, more than 80% of OSA patients remain undiagnosed. We investigated the feasibility of OSA assessment using a single-channel physiological signal to simplify the OSA screening. We detected both snoring and heartbeat information by using a piezo-electric sensor, and snoring index (SI) and features based on pulse rate variability (PRV) analysis were extracted from the filtered piezo-electric sensor signal. A support vector machine (SVM) was used as a classifier to detect OSA events. The performance of the proposed method was evaluated on 45 patients from mild, moderate, and severe OSA groups. The method achieved a mean sensitivity, specificity, and accuracy of 72.5%, 74.2%, and 71.5%; 85.8%, 80.5%, and 80.0%; and 70.3%, 77.1%, and 71.9% for the mild, moderate, and severe groups, respectively. Finally, these results not only show the feasibility of OSA detection using a piezo-electric sensor, but also illustrate its usefulness for monitoring sleep and diagnosing OSA.

Keyword

Obstructive Sleep Apnea; Snoring Index; Pulse Rate Variability; Piezo-Electric Sensor; Support Vector Machine

MeSH Terms

Heart Rate
Humans
Mass Screening*
Methods
Sensitivity and Specificity
Sleep Apnea, Obstructive*
Sleep Wake Disorders
Snoring
Support Vector Machine

Figure

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  Fig. 1 Steps of the proposed method. OSA = obstructive sleep apnea, PP = pulse-to-pulse interval, SDPP = standard deviation of the pulse-to-pulse interval, rMSSD = root mean square of successive differences, LF = low-frequency, HF = high-frequency, SI = snoring index, SVM = support vector machine.

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  Fig. 2 Snoring detection process. (A) Piezo-electric sensor signal. (B) Filtered signal. (C) Energy signal. Dashed lines highlight the snoring threshold (10 dB). (D) Detected snoring episodes.

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  Fig. 3 Heartbeat detection process. (A) Piezo-electric sensor signal. (B) Filtered signal (+) in signal shows detected peak point. (C) Reference ECG signal. ECG = electrocardiogram.

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  Fig. 4 Scatter plot of the estimated AHI and annotated AHI values. ○ = mild OSA group, △ = moderate OSA group, ⬜ = severe OSA group, AHI = apnea-hypopnea index, OSA = obstructive sleep apnea.

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