Developing Normal Turns-Amplitude Clouds for Upper and Lower Limbs

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.