Suppression of stimulus artifact contaminating electrically evoked electromyography. NeuroRehabilitation 2014;34(2):381-9
Date
01/15/2014Pubmed ID
24419021Pubmed Central ID
PMC4000584DOI
10.3233/NRE-131045Scopus ID
2-s2.0-84901919221 (requires institutional sign-in at Scopus site) 18 CitationsAbstract
BACKGROUND: Electrical stimulation of muscle or nerve is a very useful technique for understanding of muscle activity and its pathological changes for both diagnostic and therapeutic purposes. During electrical stimulation of a muscle, the recorded M wave is often contaminated by a stimulus artifact. The stimulus artifact must be removed for appropriate analysis and interpretation of M waves.
OBJECTIVES: The objective of this study was to develop a novel software based method to remove stimulus artifacts contaminating or superimposing with electrically evoked surface electromyography (EMG) or M wave signals.
METHODS: The multiple stage method uses a series of signal processing techniques, including highlighting and detection of stimulus artifacts using Savitzky-Golay filtering, estimation of the artifact contaminated region with Otsu thresholding, and reconstruction of such region using signal interpolation and smoothing. The developed method was tested using M wave signals recorded from biceps brachii muscles by a linear surface electrode array. To evaluate the performance, a series of semi-synthetic signals were constructed from clean M wave and stimulus artifact recordings with different degrees of overlap between them.
RESULTS: The effectiveness of the developed method was quantified by a significant increase in correlation coefficient and a significant decrease in root mean square error between the clean M wave and the reconstructed M wave, compared with those between the clean M wave and the originally contaminated signal. The validity of the developed method was also demonstrated when tested on each channel's M wave recording using a linear electrode array.
CONCLUSIONS: The developed method can suppress stimulus artifacts contaminating M wave recordings.
Author List
Liu J, Li S, Li X, Klein C, Rymer WZ, Zhou PAuthor
Xiaoyan Li PhD Assistant Professor in the Neurology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
ArmArtifacts
Electric Stimulation
Electromyography
Humans
Image Processing, Computer-Assisted
Muscle Contraction
Muscle, Skeletal
Software