Abstract
A microelectromechanical system is recently used for measurements of vital signs. Although the neck is regarded as an alternate observatory location of heartbeats, there have not been reports to monitor respiration electrically. The purpose of this preliminary study is to compare respiratory signals based on acceleration on the neck and humidity in exhaled air. An accelerometer on the side of the neck was used to measure respiration. The accelerometer was hooked on a neck lanyard and gently contacted the skin close to a branch of the carotid artery. We performed a frequency domain analysis (lower than 0.5 Hz for respiration and 20–40 Hz for heartbeat) to separate respiratory signals by filtering via the fast-Fourier transform. We compared the signals based on acceleration and air humidity using a respiratory sensor, which comprised of a nanoparticle film on gold microelectrodes. The two measurements of a correlation coefficient, bias, and standard deviation of a Bland–Altman plot were 0.61, 0.41, and 2.5 bpm, respectively. Additionally, we conducted tests to measure the respiration and heartbeat of a walking person. These results show that the accelerometer gently contacting the skin is capable of monitoring the respiration of people undergoing minor movements such as sitting on a chair or standing.
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Acknowledgements
We acknowledge Hirotada Hirama (National Institute of Advanced Industrial Science and Technology (AIST)) for the discussions regarding the manuscript and Thanh-Vinh Nguyen (AIST) for the advice regarding pulse wave measurements. We would like to thank Editage (www.editage.com) for English language editing.
Funding
This research was partly supported by JSPS KAKENHI (Grant Number 18K13767) and Funding of Leading Initiative for Excellent Young Researchers.
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Kano, S., Mekaru, H. Preliminary comparison of respiratory signals using acceleration on neck and humidity in exhaled air . Microsyst Technol 27, 1–9 (2021). https://doi.org/10.1007/s00542-020-04889-4
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DOI: https://doi.org/10.1007/s00542-020-04889-4