Abstract
Analogue and digital instruments for non-invasive on-line measurement of muscle fibre conduction velocity (CV) have been designed, built and compared using test signals and real myo-electric signals. Their inputs consist of two single-differential or double-differential myo-electric signals, obtained using a three- or fourcontact surface electrode system. The analogue device computes CV by tracking the lag of the zero-crossing of the cross-correlation between the first signal and the derivative of the second. The digital device computes the peak of the cross-correlation function between the two signals by sampling them at 50 KHz for 20 ms (or longer, up to 320 ms), computing CV in about 30 ms (or longer, up to about 670 ms) and resuming sampligg. Both devices allow estimation of CV during either voluntary or electrically elicited contractions and include a stimulation stage and a signal conditioner with artefact suppression features. Both devices provide analogue and numerical outputs and allow interfacing with analogue and digital instrumentation. They can be used in clinical or in research environments for easy and quick identification of appropriate electrode locations and/or for monitoring CV during sustained voluntary or electrically elicited contractions. The digital version is more versatile and requires no adjustments; it provides an estimate based on intermittent reading of the signals and is more sensitive to noise and momentary CV fluctuations.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andreassen, S., andArendt-Nielsen, L. (1987): ‘Muscle fiber conduction velocity in motor units of the human anterior tibial muscle—a new size principle parameter’,J. Physiol.,391, pp. 561–571
Arendt-Nielsen, L., Zwarts, M. (1989): ‘Measurement of muscle fiber conduction velocity in humans: techniques and applications,’J. Clin. Neurophysiol.,6, pp. 173–190
Bonato, P., Knaflitz, M., Merletti, R., andBalestra, G. (1991): ‘Comparison between muscle fiber conduction velocity estimation techniques: spectral matching versus cross-correlation,in Anderson, P., Hobart, D., andDanoff, J. (Eds.): ‘Electromyographical kinesiology’ (Elsevier Science Publisher) pp. 19–22
Brody, L., Pollock, M. T., Roy, S. H., de Luca, C. J., andCelli, B. (1991): ‘pH induced effects on median frequency and conduction velocity of the myoelectric signal’,J. Appl. Physiol.,71, pp. 1878–1885
Broman, H., Bilotto, G., andde Luca, C. J. (1985): ‘A note on the non-invasive estimation of muscle fiber conduction velocity’,IEEE Trans.,BME-32, pp. 341–344
Derrico, P., Fiorito, A., andKnaflitz, M. (1991): ‘Real-time measurement of muscle fiber conduction velocity,’ Proc. First Italian Congress of ISEK, Pisa, Italy, pp. 36–37
Graham, A., Hudgins, B., andParker, P. (1984): ‘Polarity correlator for conduction velocity measurement’,IEEE Trans.,BME-31, pp. 675–679
Guglielminotti, P., andMerletti, R. (1992): ‘Effect of electrode location on surface myoelectric signal variables: a simulation study,’ Proc. 9th Int. Congress of ISEK, Firenze, Italy, p. 188
Harba, M., andNaief, A. (1985): ‘A microprocessor-based polarity correlator for the on-line measurement of muscle fiber conduction velocity’,IEEE Trans.,BME-32, pp. 1071–1077
Harba, M., Zaia, I., andNaief, A. (1988a): ‘On-line measurement of muscle fibre conduction velocity: analysis and optimisation of performance’,J. Biomed. Eng.,10, pp. 33–45
Harba, M., Zaia, I., Naief, A., andAbid-Ali, F. (1988b): ‘Fast on-line polarity correlation algorithms for muscle fibre conduction velocity measurement.,10, pp. 411–416
Jordan, J., andManook, B. (1981): ‘A correlation function peak tracking system,’Trans. Inst. Meas. & Control.,3, pp. 66–70
Knaflitz, M., andMerletti, R. (1988): ‘Suppression of stimulation artifacts from myoelectric evoked potential recordings,’IEEE Trans.,BME-35, pp. 758–763
Lynn, P. (1979): ‘Direct on-line estimation of muscle fiber conduction velocity by surface electromyography,’IEEE Trans.,BME-26, pp. 564–571
Masuda, T., Miyano, H., andSadoyama, T. (1982): ‘The measurement of muscle fiber conduction velocity using a gradient threshold zero-crossing method’,,BME-29, pp. 673–678
McGill, K., andDorfman, L. (1984): ‘High resolution alignment of sample waveforms,,BME-31, pp. 462–468
Merletti, R., Knaflitz, M., andde Luca, C. J. (1992a): ‘Electrically evoked myo-electric signals’,Crit. Rev. Biomed. Eng.,19, pp. 293–340
Merletti, R., Lo Conte, L. R., Cisari, C., andActis, M. V. (1992b): ‘Age related changes in surface myoelectric signals,’Scand. J. Rehab. Med.,24, pp. 25–26
Roy, S. H., de Luca, C. J., andSchneider, J. (1986): ‘Effects of electrode location on myoelectric conduction velocity and median frequency estimates,’J. Appl. Physiol.,61, pp. 1510–1517
Sadoyama, T., Masuda, T., Miyata, H., andKatsuta, S. (1988): ‘Fiber conduction velocity and fiber composition in human vastus lateralis,’Eur. J. Appl. Physiol.,57, pp. 767–771
Schneider, J., Silny, J., andRau, G. (1991): ‘Influence of tissue inhomogeneities on non-invasive muscle fiber conduction velocity measurements investigated by physical and numerical modelling,’IEEE Trans.,BME-39, pp. 851–860
Zorn, H., andNaeije, M. (1983): ‘On-line muscle fibre action potential conduction velocity measurements using the surface EMG cross-correlation technique,’Med. & Biol. Eng. & Comput.,21, pp. 239–240
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Fiorito, A., Rao, S. & Merletti, R. Analogue and digital instruments for non-invasive estimation of muscle fibre conduction velocity. Med. Biol. Eng. Comput. 32, 521–529 (1994). https://doi.org/10.1007/BF02515310
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02515310