Skip to main content

Development of a practicable non-contact bedside autonomic activation monitoring system using microwave radars and its clinical application in elderly people

Abstract

We developed a practicable, non-contact, autonomic activation monitoring system using microwave radars without imposing any stress on monitored individuals. Recently, the rapid increase in the aging population has raised concerns in developed countries. Thus, hospitals and care facilities will need to perform long-term health monitoring of elderly patients. The system allows monitoring of geriatric autonomic dysfunctions caused by chronic diseases, such as diabetes or myocardial infarction (MI), while measuring vital signs in non-contact way. The system measures heart rate variability (HRV) of elderly people in bed using dual, 24-GHz, compact microwave radars attached beneath the bed mattress. HRV parameters (LF, HF, and LF/HF) were determined from the cardiac peak-to-peak intervals, which were detected by radars using the maximum entropy method. We tested the system on 15 elderly people with and without diabetes or MI (72–99 years old) from 7:00 p.m. to 6:00 a.m. at a special nursing home in Tokyo. LF/HF obtained by the system correlated significantly (R = 0.89; p < 0.01) with those obtained by Holter electrocardiography (ECG). Diabetic subjects showed significantly lower LF (radar) than non-diabetic (119.8 ± 57.8 for diabetic, 405.9 ± 112.6 for non-diabetic, p < 0.01). HF (radar) of post-MI subjects was significantly lower than that of non-MI (219.7 ± 131.7 for post-MI and 580.0 ± 654.6 for non-MI, p < 0.05). Previous studies using conventional ECG reveal that diabetic neuropathy decreases LF, and also MI causes parasympathetic attenuation which leads to HF reduction. Our study showed that average SDNN of post-MI patients is smaller than 50 ms which is known to have high mortality. The non-contact autonomic activation monitoring system allows a long-term health management especially during sleeping hours for elderly people at healthcare facilities.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10

References

  1. 1.

    Fujimoto Y, Fukuki M, Hoshio A, Sasaki N, Hamada T, Tanaka Y, Yoshida A, Shigemasa C, Mashiba H. Decreased heart rate variability in patients with diabetes mellitus and ischemic heart disease. Jpn Circ J. 1996;60(12):925–32.

    PubMed  Article  CAS  Google Scholar 

  2. 2.

    Jakobsen J, Christiansen JS, Kristoffersen I, Christensen CK, Hermansen K, Schmitz A, Mogensen CE. Autonomic and somatosensory nerve function after 2 years of continuous subcutaneous insulin infusion in type I diabetes. Diabetes. 1988;37(4):452–5.

    PubMed  Article  CAS  Google Scholar 

  3. 3.

    Orlov S, Bril V, Orszag A, Perkins BA. Heart rate variability and sensorimotor polyneuropathy in type 1 diabetes. Diabetes Care. 2012;35(4):809–16. Epub 2012.

    PubMed  Article  Google Scholar 

  4. 4.

    Craelius W, Akay M, Tangella M. Heart rate variability as an index of autonomic imbalance in patients with recent myocardial infarction. Med Biol Eng Comput. 1992;30(4):385–8.

    PubMed  Article  CAS  Google Scholar 

  5. 5.

    Counihan PJ, Fei L, Bashir Y, Farrell TG, Haywood GA, McKenna WJ. Assessment of heart rate variability in hypertrophic cardiomyopathy. Association with clinical and prognostic features. Circulation. 1993;88(4 Pt 1):1682–90.

    Article  Google Scholar 

  6. 6.

    Maestri R, Raczak G, Danilowicz-Szymanowicz L, Torunski A, Sukiennik A, Kubica J, La Rovere MT, Pinna GD. Reliability of heart rate variability measurements in patients with a history of myocardial infarction. Clin Sci. 2009;118(3):195–201.

    PubMed  Article  Google Scholar 

  7. 7.

    Matsui T, Arai I, Gotoh S, Hattori H, Takase B, Kikuchi M, Ishihara M. A novel apparatus for non-contact measurement of heart rate variability: a system to prevent secondary exposure of medical personnel to toxic materials under biochemical hazard conditions, in monitoring sepsis or in predicting multiple organ dysfunction syndrome. Biomed Pharmacother. 2005;59(Suppl 1):S188–91.

    PubMed  Article  CAS  Google Scholar 

  8. 8.

    Suzuki S, Matsui T, Imuta H, Uenoyama M, Yura H, Ishihara M, Kawakami M. A novel autonomic activation measurement method for stress monitoring: non-contact measurement of heart rate variability using a compact microwave radar. Med Biol Eng Comput. 2008;46(7):709–14. Epub 2008.

    PubMed  Article  Google Scholar 

  9. 9.

    Statistics Bureau and the Director-General for Policy Planning of Japan http://www.stat.go.jp/english/index.htm.

  10. 10.

    Kagawa M, Yoshida Y, Kubota M, Kurita A, Matsui T. Non-contact heart rate monitoring method for elderly people in bed with random body motions using 24 GHz dual radars located beneath the mattress in clinical settings. J Med Eng Technol. 2012. [Epub ahead of print].

  11. 11.

    Matsui T, Hakozaki Y, Suzuki S, Usui T, Kato T, Hasegawa K, Sugiyama Y, Sugamata M, Abe S. A novel screening method for influenza patients using a newly developed non-contact screening system. J Infect. 2010;60(4):271–7. Epub 2010.

    PubMed  Article  Google Scholar 

  12. 12.

    Uenoyama M, Matsui T, Yamada K, Suzuki S, Takase B, Suzuki S, Ishihara M, Kawakami M. Non-contact respiratory monitoring system using a ceiling-attached microwave antenna. Med Biol Eng Comput. 2006;44(9):835–40. Epub 2006.

    PubMed  Article  Google Scholar 

  13. 13.

    Matsui T, Hagisawa K, Ishizuka T, Takase B, Ishihara M, Kikuchi M. A novel method to prevent secondary exposure of medical and rescue personnel to toxic materials under biochemical hazard conditions using microwave radar and infrared thermography. IEEE Trans Biomed Eng. 2004;51(12):2184–8.

    PubMed  Article  Google Scholar 

  14. 14.

    Chen KM, Huang Y, Zhang J, Norman A. Microwave life-detection systems for searching human subjects under earthquake rubble or behind barrier. IEEE Trans Biomed Eng. 2000;47(1):105–14.

    PubMed  Article  CAS  Google Scholar 

  15. 15.

    Kleiger RE, Miller JP, Bigger JT Jr. Moss AJ Decreased heart rate variability and its association with increased mortality after acute myocardial infarction. Am J Cardiol. 1987;59(4):256–62.

    PubMed  Article  CAS  Google Scholar 

  16. 16.

    Pontet J, Contreras P, Curbelo A, Medina J, Noveri S, Bentancourt S, Migliaro ER. Heart rate variability as early marker of multiple organ dysfunction syndrome in septic patients. J Crit Care. 2003;18(3):156–63.

    PubMed  Article  Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Takemi Matsui.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Matsui, T., Yoshida, Y., Kagawa, M. et al. Development of a practicable non-contact bedside autonomic activation monitoring system using microwave radars and its clinical application in elderly people. J Clin Monit Comput 27, 351–356 (2013). https://doi.org/10.1007/s10877-013-9448-3

Download citation

Keywords

  • Autonomic activation
  • Non-contact
  • Microwave radar
  • Heart rate variability
  • Nursing home
  • Elderly people