Limitations and Applications of ICA for Surface Electromyogram

This paper reports research conducted to evaluate the use of sparse ICA for the separation of muscle activity from SEMG. It discusses some of the conditions that could affect the reliability of the separation and evaluates issues related to the properties of the signals and number of sources. The paper reports tests using Zibulevsky´s method of temporal plotting to identify number of independent sources in SEMG recordings. The theoretical analysis and experimental results demonstrate that sparse ICA is not suitable for SEMG signals. The results identify that the technique is unable to identify finite number of active muscles. The work demonstrates that even at extremely low level of muscle contraction, and with filtering using wavelets and band pass filters, it is not possible to get the data sparse enough to identify number of independent sources using Zibulevsky´s sparse decomposition technique