Journal of Sensor Science and Technology (센서학회지)

The Korean Sensors Society (한국센서학회)
권호 표지
DOI QR코드

DOI QR Code

Measurement of Apnea Using a Polyvinylidene Fluoride Sensor Inserted in the Pillow

베게에 삽입된 PVDF센서를 이용한 무호흡증 측정

  • Keum, dong-Wi (Department of Electonic Engineering, Hoseo University) ;
  • Kim, Jeong-Do (Department of Electonic Engineering, Hoseo University)
  • 금동위 (호서대학교 전자공학과) ;
  • 김정도 (호서대학교 전자공학과)
  • Received : 2018.11.07
  • Accepted : 2018.11.28
  • Published : 2018.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

Most sleep apnea patients exhibit severe snoring, and long-lasting sleep apnea may cause insomnia, hypertension, cardiovascular diseases, stroke, and other diseases. Although polysomnography is the typical sleep diagnostic method to accurately diagnose sleep apnea by measuring a variety of bio-signals that occur during sleep, it is inconvenient as the patient has to sleep with attached electrodes at the hospital for the diagnosis. In this study, a diagnostic pillow is designed to measure respiration, heart rate, and snoring during sleep, using only one polyvinylidene fluoride (PVDF) sensor. A PVDF sensor with piezoelectric properties was inserted into a specially made instrument to extract accurate signals regardless of the posture during sleep. Wavelet analysis was used to identify the extractability and frequency domain signals of respiration, heart rate, and snoring from the signals generated by the PVDF sensor. In particular, to separate the respiratory signal in the 0.2~0.5 Hz frequency region, wavelet analysis was performed after removing 1~2 Hz frequency components. In addition, signals for respiration, heart rate, and snoring were separated from the PVDF sensor signal through a Butterworth filter and median filter based on the information obtained from the wavelet analysis. Moreover, the possibility of measuring sleep apnea from these separated signals was confirmed. To verify the usefulness of this study, data obtained during sleeping was used.

Keywords

HSSHBT_2018_v27n6_407_f0001.png 이미지

Fig. 1. Appearance and structure of PVDF sensor

HSSHBT_2018_v27n6_407_f0002.png 이미지

Fig. 2. Structure of Sleep Diagnosis Pillow

HSSHBT_2018_v27n6_407_f0003.png 이미지

Fig. 3. Signal of PVDF sensor measured during sleep

HSSHBT_2018_v27n6_407_f0004.png 이미지

Fig. 4. Analysis results through STFT (a) 0~5,000 Hz, (b) 0~200Hz

HSSHBT_2018_v27n6_407_f0005.png 이미지

Fig. 5. Analysis results through Wavelet Transform

HSSHBT_2018_v27n6_407_f0006.png 이미지

Fig. 6. Wavelet analysis of low frequency range

HSSHBT_2018_v27n6_407_f0007.png 이미지

Fig. 7. Breathing signals acquired through 4th Butterworth low-pass filtering (Cut-off Frequency= 0.25 Hz)

HSSHBT_2018_v27n6_407_f0008.png 이미지

Fig. 8. Structure for extracting heart rate signal

HSSHBT_2018_v27n6_407_f0009.png 이미지

Fig. 9. R-peak detection using median filter

HSSHBT_2018_v27n6_407_f0010.png 이미지

Fig. 10. Snoring signal synchronized with breathing signal

HSSHBT_2018_v27n6_407_f0011.png 이미지

Fig. 11. Snoring signal acquired through 4th HPF

HSSHBT_2018_v27n6_407_f0012.png 이미지

Fig. 12. High-frequency noise-canceled snoring signal

HSSHBT_2018_v27n6_407_f0013.png 이미지

Fig. 13. Median filter obtained snoring signal

HSSHBT_2018_v27n6_407_f0014.png 이미지

Fig. 14. Extraction of proposed snoring signal

HSSHBT_2018_v27n6_407_f0015.png 이미지

Fig. 15. Heart rate signal obtained using Median Filter and heart rate signal obtained using MP150 system

HSSHBT_2018_v27n6_407_f0016.png 이미지

Fig. 16. Respiratory and snoring signals (a) not using the median filter (b) using median filter

HSSHBT_2018_v27n6_407_f0017.png 이미지

Fig. 17. Comparison of breathing and noise signals (a) not using the median filter (b) using median filter

HSSHBT_2018_v27n6_407_f0018.png 이미지

Fig. 18. Respiratory and Snoring Signals in Patients with Apnea (a) not using the median filter (b) using median filter

HSSHBT_2018_v27n6_407_f0019.png 이미지

Fig. 19. Comparison of Respiratory Signals and Snoring Signals in Patients with Apnea (105~165 secs) (a) not using the median filter (b) using median filter

References

  1. S. Javaheri, F. Barbe, F. Campos-Rodriguez, J. A. Dempsey, R. Khayat, S. Javaheri, A. Malhotra, M. A. Martinez-Garcia, R. Mehra, A. I. Pack, V. Y. Polotsky, MD, S. Redline, V. K. Somers, Sleep Apnea : Types, Mechanisms, and Clinical Cardiovascular Consequences", Journal of the American College of Cardiology, Vol.69 No.7, pp.841-858, 2017 https://doi.org/10.1016/j.jacc.2016.11.069
  2. S. Choi and Z. Jiang, "A novel wearable sensor device with conductive fabric and PVDF film for monitoring cardiorespiratory signals", Sens. Actuators. A, Vol. 128, No. 2, pp. 317-326, 2006. https://doi.org/10.1016/j.sna.2006.02.012
  3. A. Vehkaoja, A. Kontunen, J. Lekkala, "Effects of sensor type and sensor location on signal quality in bed mounted ballistocardiographic heart rate and respiration monitoring", Proc. Of 37th Annu. Int. Conf. of IEEE Engineering in Medicine and Biological Society, pp.4383-4386, Milano, Italy, 2015.
  4. I. Mahbub, S. Islam, S. Shamsir, S. A. Pullano, A. S. Fiorillo, M. S. Gaylord and V. Lorch, V, "A low power wearable respiration monitoring sensor using pyroelectric transducer", Conf. of U. S. Natl . Comm. of URSI Natl, Boulder, Colorado, USA., 2017.
  5. V. K. Nithya, P. K. S. Kumar, and A. V. Juliet, "Design of a MEMS sensor for sleep apnea detection", 10th Int. Conf. on Intelligent systems and Control, pp.1-5, Coimbatore, India 2016.
  6. S. Uchida, T. Endo, K. Suenaga, H. Iwami, S. Inoue, E. Fujioka, A. Imamura, T. Atsumi, Y. Inagaki, and A. Kamei, "Sleep evaluation by a newly developed PVDF sensor noncontact sheet: a comparison with standard polysomnography and wrist actigraphy", Sleep and Biol. Rhythms, Vol. 9, No. 3, pp.178-187, 2011. https://doi.org/10.1111/j.1479-8425.2011.00506.x
  7. F. K. Shiomi, I. T. Pisa, and C. J. Campos, "Computerized analysis of snoring in Sleep Apnea Syndrome", Braz. J. Otorhinolaryngol. Vol. 77, No. 4, pp. 488-98, 2011. https://doi.org/10.1590/S1808-86942011000400013