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Developing Normal Turns–Amplitude Clouds for Upper and Lower Limbs

Jabre, Joe F.; Nikolayev, Sergey G.; Babayev, Michael B.; Chindilov, Denis V.; Muravyov, Anatoly Y.

Journal of Clinical Neurophysiology: October 2016 - Volume 33 - Issue 5 - p 458–463
doi: 10.1097/WNP.0000000000000267
Original Research

Purpose: Turns and amplitude analysis (T&A) is a frequently used method for automatic EMG interference pattern analysis. The T&A normal values have only been developed for a limited number of muscles. Our objective was to obtain normal T&A clouds for upper and lower extremity muscles for which no normal values exist in the literature.

Methods: The T&A normative data using concentric needle electrodes were obtained from 68 men and 56 women aged 20 to 60 years.

Results: Normal upper and lower extremity T&A clouds were obtained and presented in this article.

Conclusion: The T&A normal values collected in this study maybe used to detect neurogenic and myopathic abnormalities in men and women at low-to-moderate muscle contractions. The effect of turns–amplitude data obtained at high force level of muscle contraction and its potential to falsely show neurogenic abnormalities are discussed.

*Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, U.S.A.;

Neurophysiological Centre, Elf Ltd Medical Company, Vladimir, Russia;

Innovations Department, Neurosoft Ltd, Ivanovo, Russia;

§Department of Mathematical Software, Neurosoft Ltd, Ivanovo, Russia; and

Department of Functional Diagnostics, Regional Hospital for War Veterans, Ivanovo, Russia.

Address correspondence and reprint requests to Joe F. Jabre, MD, 170 N Poinsettia Pl, Los Angeles, CA 90036, U.S.A.; e-mail:

The authors declare no conflicts of interest.

© 2016 by the American Clinical Neurophysiology Society