Nadi Yantra: a robust system design to capture the signals from the radial artery for assessment of the autonomic nervous system non-invasively


Ayurvedic and other alternative medical practi-tioners throughout the world have been using pulse diagnosis to detect disease and the organ at distress by feeling the palpations at three close yet precise positions of the radial artery. This paper presents a robust electro-mechanical system, ‘Nadi Yantra’ which uses piezoelectric based pressure sensors to capture the signals from the radial artery. Morphology of the waveforms obtained from our system concurs with standard physiological arterial signals. Reproducibility and stability of the system has been verified. Signal processing techniques were applied to obtain features such as amplitude, power spectral density, bandpower and spectral centroid to reflect variations in signals from the three channels. Further, wavelet based techniques were used to process the pressure signals and percussion peaks were identified. The interval between the percussion peaks was used to calculate Heart Rate Varibility (HRV), a useful tool for assessing the status of the autonomic nervous system of the human body non-invasively. Time domain indices were calculated from direct measurement of peak-peak (PP) intervals and from differences between the PP intervals. Frequency domain indices such as very low frequency (VLF) power, low frequency (LF) power, high frequency (HF) power, LF/HF ratio were also calculated. Thereafter, nonlinear Poincare analysis was carried out. A map of consecutive PP intervals was fitted to an ellipse using least squares method. Results from 7 datasets are depicted in this paper. A novel pressure pulse recording instrument is deve loped for the objective assessment of the ancient sci-ence of pulse diagnosis. The features calculated using multi resolution wavelet analysis show potential in the evaluation of the autonomic nervous system of the human body.

Share and Cite:

bhinav, A. , Sareen, M. , Kumar, M. , Santhosh, J. , Salhan, A. and Anand, S. (2009) Nadi Yantra: a robust system design to capture the signals from the radial artery for assessment of the autonomic nervous system non-invasively. Journal of Biomedical Science and Engineering, 2, 471-479. doi: 10.4236/jbise.2009.27068.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Yoon, Y., Lee, M., and Soh, K., (2000) Pulse type classi- fica-tion by varying contact pressure, IEEE Engineering in Medi-cine and Biology Magazine, 19, 106–110.
[2] Fuzzy Theory in Traditional Chinese Pulse Diagnosis, Pro-ceedings of 1993 International Joint Conference on Neural Networks.
[3] Wang, H. and Cheng, Y., (2005) A quantitative system for pulse diagnosis in traditional chinese medicine, IEEE EMBS, 5676–5679.
[4] Xu, L. S., Wang, K. Q., and Zhang, D., (2002) Modern re-searches on pulse waveform of TCPD, IEEE.
[5] Joshi, A., Kulkarni, A., Chandran, S., Jayaraman, V. K., and Kulkarni, B. D., Nadi tarangini: A pulse based diagnostic sys-tem, Proceedings of the 29th Annual International Conference of the IEEE EMBS.
[6] Grap, A., (1995) An introduction to wavelets, IEEE Comp. Sc. and Engg., 2(2).
[7] Torrence, C. and Compo, G. P., (1998) A practical guide to wavelet analysis, American Meteorological Society.
[8] Holger, G. and Adelmann, (1999) Design of a PC-based system for time-domain and spectral analysis of heart rate variability, Computers and Biomedical Research, 32, 77–92.
[9] Task Force of the European Society of Cardiology and The North American Society of Pacing and Electrophysiology, (1996) Heart rate variability standards of measurement, physiological interpretation and Clinical use, European Heart Journal, 17, 354–381.
[10] Malik, M., (1996) Heart rate variability–Standards of meas-urement, physiological interpretation and clinical use–Task Force–European Society of Cardiology and The North Ameri-can Society of Pacing and Electrophysi- ologu, Eur. Heart J., 17(354), 81.
[11] Brennan, M., Palaniswami, M., and Kamen, P., (2002) Poin-care plot interpretation using a physiological model of HRV based on a network of oscillators, Am. J. Physiol. 283: H1873-H1886.

Copyright © 2024 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.