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A wearable echomyography system based on a single transducer

Nature Electronics volume 7, pages 1035–1046 (2024)Cite this article

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Abstract

Wearable electromyography devices can detect muscular activity for health monitoring and body motion tracking, but this approach is limited by weak and stochastic signals with a low spatial resolution. Alternatively, echomyography can detect muscle movement using ultrasound waves, but typically relies on complex transducer arrays, which are bulky, have high power consumption and can limit user mobility. Here we report a fully integrated wearable echomyography system that consists of a customized single transducer, a wireless circuit for data processing and an on-board battery for power. The system can be attached to the skin and provides accurate long-term wireless monitoring of muscles. To illustrate its capabilities, we use this system to detect the activity of the diaphragm, which allows the recognition of different breathing modes. We also develop a deep learning algorithm to correlate the single-transducer radio-frequency data from forearm muscles with hand gestures to accurately and continuously track 13 hand joints with a mean error of only 7.9°.

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Fig. 1: Overview of the fully integrated wearable single-transducer EcMG system.
Fig. 2: Acousto-electric characterization.
Fig. 3: Continuous diaphragm monitoring using RF signals directly.
Fig. 4: Diaphragm monitoring of patients with COPD and healthy participant.
Fig. 5: Dynamic hand gesture tracking using deep learning.
Fig. 6: Human–machine interface using the wearable EcMG system.

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Data availability

All data are available in the Article or its Supplementary Information.

Code availability

Code used in this work is available via GitHub at https://github.com/XiaoxiangGao/single_transducer_project.

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Acknowledgements

The system was based on research sponsored by the National Institutes of Health (NIH) grant no. 1R21EB025521-01 (S.X.), grant no. 1R21EB027303-01A1 (S.X.), grant no. 3R21EB027303-02S1 (S.X.) and grant no. 1R01 EB033464-01 (S.X.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. All the biological experiments were conducted in accordance with the ethical guidelines with the approval of the Institutional Review Board of the University of California San Diego.

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Author notes

  1. These authors contributed equally: Xiaoxiang Gao, Xiangjun Chen, Muyang Lin, Wentong Yue.

Authors and Affiliations

  1. Aiiso Yufeng Li Family Department of Chemical and Nano Engineering, University of California San Diego, La Jolla, CA, USA

    Xiaoxiang Gao, Muyang Lin, Wentong Yue, Hongjie Hu, Zhiyuan Lou, Lu Yin, Hao Huang, Yizhou Bian, Xinyu Wang, Geonho Park, Ruotao Wang, Ray S. Wu, Joseph Wang & Sheng Xu

  2. Materials Science and Engineering Program, University of California San Diego, La Jolla, CA, USA

    Xiangjun Chen, Fangao Zhang, Sai Zhou, Xinyi Yang, Jing Mu & Sheng Xu

  3. Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA, USA

    Siyu Qin, Chengchangfeng Lu & Sheng Xu

  4. Terasaki Institute for Biomedical Innovation, Los Angeles, CA, USA

    Yangzhi Zhu

  5. Department of Medicine, University of California San Diego, La Jolla, CA, USA

    Jinghong Li

  6. Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, La Jolla, CA, USA

    Sheng Xu

  7. Department of Radiology, School of Medicine, University of California San Diego, La Jolla, CA, USA

    Sheng Xu

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Contributions

X.G. and S.X. conceived the study and designed the experiments. X.G., X.C., W.Y., S.Q., F.Z. and Z.L. performed the experiments. X.G. processed the data. M.L. designed the circuit. L.Y. fabricated the 3D-printed mould. J.L. recruited the patients. X.G., X.C., M.L., J.L. and S.X. wrote the manuscript. H. Hu, H. Huang, S.Z., Y.B., X.Y., Y.Z., J.M., X.W., G.P., C.L., R.W., R.S.W., J.W. and J.L. discussed the experimental results and reviewed the manuscript.

Corresponding author

Correspondence to Sheng Xu.

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The authors declare no competing interests.

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Peer review information

Nature Electronics thanks Yuan Huang, Alina Rwei and Lizhi Xu for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Notes 1–13, Figs. 1–32, Tables 1–5, captions for for Supplementary Videos 1–3 and references.

Reporting Summary

Supplementary Video 1

Simultaneous measurements of EcMG and EMG signals as the fingers bend and the wrist rotates.

Supplementary Video 2

Real-time virtual bird control by correlating the pitch angle of the wrist with the height of the virtual bird.

Supplementary Video 3

Real-time robotic arm control by correlating the pitch angle of the wrist and finger joint angle with motions of the robotic arm.

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Gao, X., Chen, X., Lin, M. et al. A wearable echomyography system based on a single transducer. Nat Electron 7, 1035–1046 (2024). https://doi.org/10.1038/s41928-024-01271-4

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